The URL can be used to link to this page

Home My WebLink About; ; Municipal NPDES Permit Order No. 2001-01; 2005-12-01Prepared for: County of San Diego 9325 Hazard Way, MS 0326 San Diego, California 92123 December 2005 Prepared for: County of San Diego 9325 Hazard Way, MS 0326 San Diego, California 92123 December 2005 2433 Impala Drive Carlsbad, CA 92010 In association with: EnviroMatrix Analytical, Inc. SAN DIEGO COUNTY MUNICIPAL COPERMITTEES 2004-2005 URBAN RUNOFF MONITORING Final Report SAN DIEGO COUNTY MUNICIPAL COPERMITTEES 2004-2005 URBAN RUNOFF MONITORING Final Report SOLUTIONSSOLUTIONS SAN DIEGO COUNTY MUNICIPAL COPERMITTEES 2004-2005 URBAN RUNOFF MONITORING Final Report Prepared for: County of San Diego 9325 Hazard Way, MS 0326 San Diego, California 92112 Prepared by: Weston Solutions, Inc. 2433 Impala Drive Carlsbad, CA 92010 In association with: EnviroMatrix Analytical, Inc. December 2005 Table of Contents 2004-2005 Urban Runoff Monitoring Report i VOLUME I LIST OF TABLES.......................................................................................................................................... ix LIST OF FIGURES.......................................................................................................................................xiv LIST OF ACRONYMS AND ABBREVIATIONS.......................................................................................xviii LIST OF CONTRIBUTORS........................................................................................................................xxi EXECUTIVE SUMMARY .........................................................................................................................ES-1 1.0 INTRODUCTION........................................................................................................................1-1 1.1 Background......................................................................................................................1-1 1.2 Monitoring Program History............................................................................................1-3 1.2.1 1993-1994 Objectives and Key Elements...........................................................1-3 1.2.2 1994-1995 Objectives and Key Elements...........................................................1-4 1.2.3 1995-1996 Objectives and Key Elements...........................................................1-5 1.2.4 1996 – 2000 Objectives and Key Elements........................................................1-7 1.2.5 2000-2001 Objectives and Key Elements...........................................................1-8 1.2.6 2001-2002 Objectives and Key Elements...........................................................1-8 1.2.6.1 Water Quality Monitoring at the Mass Loading Stations....................1-9 1.2.6.2 Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring.....1-10 1.2.6.3 Rapid Stream Bioassessment Monitoring..........................................1-10 1.2.6.4 Toxic Hot Spot Monitoring in San Diego Bay...................................1-10 1.2.6.5 Coastal Outfall Monitoring ...............................................................1-11 1.2.7 2002 – 2003 Objectives and Key Elements......................................................1-11 1.2.7.1 Water Quality Monitoring at the Mass Loading Stations..................1-11 1.2.7.2 Ambient Bay, Lagoon and Coastal Receiving Water Monitoring......1-11 1.2.7.3 Rapid Stream Bioassessment Monitoring..........................................1-12 1.2.7.4 Toxic Hot Spot Monitoring in San Diego Bay...................................1-12 1.2.7.5 Coastal Outfall Monitoring ...............................................................1-12 1.2.8 2003 – 2004 Objectives and Key Elements......................................................1-12 1.2.8.1 Water Quality Monitoring at the Mass Loading Stations..................1-12 1.2.8.2 Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring.....1-13 1.2.8.3 Rapid Stream Bioassessment Monitoring..........................................1-13 1.2.8.4 Toxic Hot Spot Monitoring in San Diego Bay...................................1-14 1.2.8.5 Coastal Outfall Monitoring ...............................................................1-14 1.3 2004-2005 Scope of Work.............................................................................................1-14 1.3.1.1 Water Quality Monitoring at the Mass Loading Stations..................1-14 1.3.1.2 Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring.....1-18 1.3.1.3 Rapid Stream Bioassessment Monitoring..........................................1-18 1.3.1.4 Toxic Hot Spot Monitoring in San Diego Bay...................................1-19 1.3.1.5 Coastal Outfall Monitoring ...............................................................1-19 1.4 Report Organization ......................................................................................................1-19 2.0 STUDY AREA DESCRIPTION......................................................................................................2-1 2.1 Regional Setting................................................................................................................2-1 2.1.1 Geomorphology..................................................................................................2-1 2.1.2 Significant Regional Events..................................................................................2-3 2.1.2.1 Wildfires..............................................................................................2-3 2.1.2.2 Large Storms and Record Rainfall.......................................................2-3 2.1.3 Rainfall and Climate.............................................................................................2-4 Table of Contents 2004-2005 Urban Runoff Monitoring Report ii 2.1.4 Hydrology...........................................................................................................2-7 2.1.5 Land Areas........................................................................................................2-13 2.1.6 Land Use...........................................................................................................2-15 2.1.7 Population.........................................................................................................2-18 2.2 Monitoring Site Descriptions .........................................................................................2-20 2.3 Storm Event Summary...................................................................................................2-24 2.3.1 Representative Storm Event.............................................................................2-24 2.3.2 Precipitation During Monitored Events............................................................2-26 2.3.3 Storm Water Runoff During Monitored Events................................................2-26 3.0 STORM WATER MONITORING METHODS AND RESULTS ...................................................3-1 3.1 Storm Water Monitoring Methods ..................................................................................3-1 3.1.1 Mass Loading Station (MLS) Site Selection..........................................................3-1 3.1.2 Monitoring Equipment........................................................................................3-1 3.1.3 Sampling Procedures ..........................................................................................3-2 3.1.3.1 Grab Samples......................................................................................3-2 3.1.3.2 Composite Samples............................................................................3-2 3.1.4 Stream Rating Methods.......................................................................................3-3 3.1.5 Sample Handling and Processing.........................................................................3-3 3.1.6 Laboratory Analysis.............................................................................................3-4 3.1.6.1 Chemical Constituents .......................................................................3-4 3.1.6.2 Toxicity Testing..................................................................................3-4 3.1.6.3 Microbiology Testing..........................................................................3-9 3.2 Rapid Stream Bioassessment Methods ..........................................................................3-10 3.2.1 Materials and Methods......................................................................................3-11 3.2.2 Monitoring Reaches ..........................................................................................3-11 3.2.3 Monitoring Reach Delineation..........................................................................3-15 3.2.4 Sample Collection.............................................................................................3-15 3.2.5 Physical Habitat Quality Assessment................................................................3-15 3.2.6 Laboratory Processing and Analysis..................................................................3-16 3.2.7 Data and Statistical Analysis..............................................................................3-16 3.3 Ambient Bay and Lagoon Monitoring.............................................................................3-18 3.3.1 Objectives and Approach..................................................................................3-18 3.3.2 Validation of Approach .....................................................................................3-19 3.3.3 Phase I – Contaminant Targeting......................................................................3-21 3.3.3.1 Site Locations....................................................................................3-21 3.3.3.2 Sampling Design................................................................................3-23 3.3.3.3 Sample Collection.............................................................................3-25 3.3.4 Phase II – Sediment Assessment.......................................................................3-25 3.3.4.1 Priority Ranking ................................................................................3-25 3.3.4.2 Sample Collection.............................................................................3-26 3.3.4.3 Water Quality...................................................................................3-26 3.3.4.4 Sediment Chemistry.........................................................................3-26 3.3.4.5 Sediment Toxicity.............................................................................3-27 3.3.4.6 Benthic Infauna .................................................................................3-27 3.3.5 Data Assessment...............................................................................................3-29 3.3.5.1 Sediment Chemistry.........................................................................3-29 3.3.5.2 Sediment Toxicity.............................................................................3-31 3.3.5.3 Benthic Infauna Data.........................................................................3-31 3.3.5.4 Data Integration................................................................................3-31 Table of Contents 2004-2005 Urban Runoff Monitoring Report iii 3.4 Watershed Management Area Assessment and Long-Term Effectiveness Assessment Rating Methods...........................................................................................3-32 3.4.1 Watershed Management Area Assessment Methods.......................................3-32 3.4.2 Long-Term Effectiveness Assessment–Water Quality Priority Rating Methodology..................................................................................................................3-41 3.5 Watershed Assessment Statistical Methods...................................................................3-47 3.5.1 Relationships and Trends..................................................................................3-47 3.6 Cross Watershed Statistical Methods............................................................................3-48 3.6.1 COC Comparisons...........................................................................................3-48 3.6.2 Relationships between Toxicity and COC........................................................3-49 3.6.2.1 Multiple Regression Analysis of Toxicity Data..................................3-49 3.6.2.2 Threshold Analyses...........................................................................3-50 4.0 SANTA MARGARITA RIVER WMA..............................................................................................4-1 4.1 Monitoring Site Descriptions ...........................................................................................4-1 4.2 Storm Water Monitoring Summary .................................................................................4-4 4.2.1 2004/2005Results................................................................................................4-4 4.2.2 Relationships/Analyses ........................................................................................4-7 4.2.3 TIEs...................................................................................................................4-10 4.2.4 Summary and Conclusions................................................................................4-10 4.3 Stream Bioassessment....................................................................................................4-10 4.3.1 Results and Discussion......................................................................................4-10 4.3.2 Summary and Conclusions................................................................................4-14 4.4 Ambient Bay and Lagoon Monitoring Program..............................................................4-14 4.4.1 Results and Discussion for Santa Margarita River Estuary................................4-14 4.4.1.1 Phase I Results and Discussion for Santa Margarita River Estuary....4-14 4.4.1.2 Phase II Results and Discussion for Santa Margarita River Estuary...4-15 4.4.1.3 Summary and Conclusions for Santa Margarita River Estuary..........4-17 4.4.2 Results and Discussion for Oceanside Harbor..................................................4-18 4.4.2.1 Phase I Results and Discussion for Oceanside Harbor.....................4-18 4.4.2.2 Phase II Results and Discussion for Oceanside Harbor....................4-19 4.4.2.3 Summary and Conclusions for Oceanside Harbor...........................4-21 4.5 WMA Assessment..........................................................................................................4-21 4.6 Conclusions and Recommendations..............................................................................4-26 5.0 SAN LUIS REY RIVER WATERSHED MANAGEMENT AREA.....................................................5-1 5.1 Monitoring Site Descriptions ...........................................................................................5-1 5.2 Storm Water Monitoring Summary .................................................................................5-4 5.2.1 2004/2005 Results...............................................................................................5-4 5.2.2 Relationships/Analyses ........................................................................................5-4 5.2.3 TIEs...................................................................................................................5-10 5.2.4 Summary and Conclusions................................................................................5-10 5.3 Stream Bioassessment....................................................................................................5-10 5.3.1 Results and Discussion......................................................................................5-10 5.3.2 Summary and Conclusions................................................................................5-14 5.4 Ambient Bay and Lagoon Monitoring Program..............................................................5-14 5.4.1 Results and Discussion......................................................................................5-14 5.4.1.1 Phase I Results and Discussion..........................................................5-14 5.4.1.2 Phase II Results and Discussion.........................................................5-15 5.4.1.3 Summary and Conclusions................................................................5-17 Table of Contents 2004-2005 Urban Runoff Monitoring Report iv 5.5 WMA Assessment..........................................................................................................5-17 5.6 Conclusions and Recommendations..............................................................................5-22 6.0 CARLSBAD WATERSHED MANAGEMENT AREA.....................................................................6-1 6.1 Monitoring Site Descriptions ...........................................................................................6-1 6.2 Storm Water Monitoring Summary .................................................................................6-6 6.2.1 2004/2005 Results...............................................................................................6-6 6.2.2 Relationships/Analyses ......................................................................................6-11 6.2.3 Third Party Data...............................................................................................6-16 6.2.4 TIEs...................................................................................................................6-17 6.2.5 Summary and Conclusions................................................................................6-17 6.3 Stream Bioassessment....................................................................................................6-17 6.3.1 Results and Discussion......................................................................................6-17 6.3.2 Summary and Conclusions................................................................................6-21 6.4 Ambient Bay and Lagoon Monitoring Program..............................................................6-22 6.4.1 Results and Discussion Buena Vista Lagoon......................................................6-22 6.4.1.1 Phase I Results and Discussion..........................................................6-22 6.4.1.2 Phase II Results and Discussion.........................................................6-23 6.4.1.3 Summary and Conclusions................................................................6-25 6.4.2 Results and Discussion for Agua Hedionda Lagoon..........................................6-26 6.4.2.1 Phase I Results and Discussion..........................................................6-26 6.4.2.2 Phase II Results and Discussion.........................................................6-27 6.4.2.3 Summary and Conclusions................................................................6-29 6.4.3 Results and Discussion for Batiquitos Lagoon...................................................6-30 6.4.3.1 Phase I Results and Discussion..........................................................6-30 6.4.3.2 Phase II Results and Discussion.........................................................6-31 6.4.3.3 Summary and Conclusions................................................................6-33 6.4.4 Results and Discussion for San Elijo Lagoon.....................................................6-34 6.4.4.1 Phase I Results and Discussion..........................................................6-34 6.4.4.2 Phase II Results and Discussion.........................................................6-35 6.4.4.3 Summary and Conclusions................................................................6-36 6.5 WMA Assessment..........................................................................................................6-37 6.6 Conclusions and Recommendations..............................................................................6-46 7.0 SAN DIEGUITO RIVER WATERSHED MANAGEMENT AREA..................................................7-1 7.1 Monitoring Site Descriptions ...........................................................................................7-1 7.2 Storm Water Monitoring Summary .................................................................................7-4 7.2.1 2004-2005 Results ..............................................................................................7-4 7.2.2 Relationships/Analyses ........................................................................................7-7 7.2.3 TIEs...................................................................................................................7-10 7.2.4 Summary and Conclusions................................................................................7-10 7.3 Stream Bioassessment....................................................................................................7-10 7.3.1 Results and Discussion......................................................................................7-10 7.3.2 Summary and Conclusions................................................................................7-13 7.4 Ambient Bay and Lagoon Monitoring.............................................................................7-13 7.4.1 Results and Discussion......................................................................................7-13 7.4.1.1 Phase I Results and Discussion..........................................................7-13 7.4.1.2 Phase II Results and Discussion.........................................................7-14 7.4.1.3 Summary and Conclusions................................................................7-16 7.5 WMA Assessment..........................................................................................................7-17 7.6 Conclusions and Recommendations..............................................................................7-21 Table of Contents 2004-2005 Urban Runoff Monitoring Report v 8.0 LOS PEÑASQUITOS CREEK WATERSHED MANAGEMENT AREA.........................................8-1 8.1 Monitoring Site Descriptions ...........................................................................................8-1 8.2 Storm Water Monitoring Summary .................................................................................8-4 8.2.1 2004-2005 Results ..............................................................................................8-4 8.2.2 Relationships/Analyses ........................................................................................8-7 8.2.3 Third Party Data.................................................................................................8-9 8.2.4 TIEs.....................................................................................................................8-9 8.2.5 Summary and Conclusions..................................................................................8-9 8.3 Stream Bioassessment....................................................................................................8-11 8.3.1 Results and Discussion......................................................................................8-11 8.3.2 Summary and Conclusions................................................................................8-14 8.4 Ambient Bay and Lagoon Monitoring.............................................................................8-14 8.4.1 Results and Discussion......................................................................................8-14 8.4.1.1 Phase I Results and Discussion..........................................................8-14 8.4.1.2 Phase II Results and Discussion.........................................................8-15 8.4.1.3 Summary and Conclusions................................................................8-17 8.5 WMA Assessment..........................................................................................................8-18 8.6 Conclusions and Recommendations..............................................................................8-22 9.0 MISSION BAY WATERSHED MANAGEMENT AREA.................................................................9-1 9.1 Monitoring Site Descriptions ...........................................................................................9-1 9.2 Storm Water Monitoring Summary .................................................................................9-4 9.2.1 2004-2005 Results ..............................................................................................9-4 9.2.2 Relationships/Analyses ........................................................................................9-8 9.2.3 Third Party Data...............................................................................................9-10 9.2.4 TIEs...................................................................................................................9-12 9.2.5 Summary and Conclusions................................................................................9-12 9.3 Stream Bioassessment....................................................................................................9-12 9.3.1 Results and Discussion......................................................................................9-12 9.3.2 Summary and Conclusions................................................................................9-15 9.4 Ambient Bay and Lagoon Monitoring.............................................................................9-15 9.4.1 Results and Discussion......................................................................................9-15 9.4.1.1 Phase I Results and Discussion..........................................................9-15 9.4.1.2 Phase II Results and Discussion.........................................................9-16 9.4.1.3 Summary and Conclusions................................................................9-18 9.5 WMA Assessment..........................................................................................................9-19 9.6 Conclusions and Recommendations..............................................................................9-24 10.0 SAN DIEGO RIVER WATERSHED MANAGEMENT AREA......................................................10-1 10.1 Monitoring Site Descriptions .........................................................................................10-1 10.2 Storm Water Monitoring Summary ...............................................................................10-4 10.2.1 2004-2005 Results ............................................................................................10-4 10.2.2 Relationships/Analyses ......................................................................................10-7 10.2.3 Third Party Data...............................................................................................10-9 10.2.4 TIEs...................................................................................................................10-9 10.2.5 Summary and Conclusions................................................................................10-9 10.3 Stream Bioassessment..................................................................................................10-11 10.3.1 Results and Discussion....................................................................................10-11 10.3.2 Summary and Conclusions..............................................................................10-14 10.4 Ambient Bay and Lagoon Monitoring...........................................................................10-14 Table of Contents 2004-2005 Urban Runoff Monitoring Report vi 10.5 WMA Assessment........................................................................................................10-14 10.6 Conclusions and Recommendations............................................................................10-19 11.0 SAN DIEGO BAY WATERSHED MANAGEMENT AREA.........................................................11-1 11.1 Monitoring Site Descriptions .........................................................................................11-1 11.2 Storm Water Monitoring Summary ...............................................................................11-8 11.2.1 2004-2005 Results ............................................................................................11-8 11.2.2 Relationships/Analyses ....................................................................................11-14 11.2.3 TIEs.................................................................................................................11-20 11.2.4 Summary and Conclusions..............................................................................11-20 11.3 Stream Bioassessment..................................................................................................11-20 11.3.1 Results and Discussion....................................................................................11-20 11.3.2 Summary and Conclusions..............................................................................11-24 11.4 Ambient Bay and Lagoon Monitoring Program............................................................11-24 11.4.1 Results and Discussion....................................................................................11-24 11.4.1.1 Phase I Results and Discussion........................................................11-24 11.4.1.2 Phase II Results and Discussion.......................................................11-25 11.4.1.3 Summary and Conclusions..............................................................11-27 11.5 WMA Assessment........................................................................................................11-27 11.6 Conclusions and Recommendations............................................................................11-36 12.0 TIJUANA RIVER WATERSHED MANAGEMENT AREA ...........................................................12-1 12.1 Monitoring Site Descriptions .........................................................................................12-1 12.2 Storm Water Monitoring Summary ...............................................................................12-4 12.2.1 2004-2005 Results ............................................................................................12-4 12.2.2 Relationships/Analyses ......................................................................................12-7 12.2.3 TIEs.................................................................................................................12-11 12.2.4 Summary and Conclusions..............................................................................12-11 12.3 Stream Bioassessment..................................................................................................12-11 12.3.1 Results and Discussion....................................................................................12-11 12.3.2 Summary and Conclusions..............................................................................12-14 12.4 Ambient Bay and Lagoon Monitoring...........................................................................12-15 12.4.1 Results and Discussion....................................................................................12-15 12.4.1.1 Phase I Results and Discussion........................................................12-15 12.4.1.2 Phase II Results and Discussion.......................................................12-16 12.4.1.3 Summary and Conclusions..............................................................12-18 12.5 WMA Assessment........................................................................................................12-19 12.6 Conclusions and Recommendations............................................................................12-24 13.0 REGIONAL ASSESSMENTS........................................................................................................13-1 13.1 Cross Watershed Comparison ......................................................................................13-1 13.1.1 Statistical Analyses ............................................................................................13-5 13.1.1.1 Magnitude of WQO Exceedance and Trend Analysis Results..........13-5 13.1.1.2 ANOVA Results..............................................................................13-18 13.1.1.3 Cluster Results................................................................................13-21 13.1.2 Relationships Between Toxicity and Constituents of Concern ......................13-23 13.2 Storm Water Modeling ................................................................................................13-31 13.2.1 Static Storm Water Modeling..........................................................................13-31 13.2.1.1 Model Description..........................................................................13-31 13.2.1.2 Model Results and Discussion.........................................................13-34 13.2.2 Water Quality Variability during Storm Events...............................................13-36 Table of Contents 2004-2005 Urban Runoff Monitoring Report vii 13.3 Dry Weather Data Analysis Results .............................................................................13-38 13.4 Rapid Stream Bioassessment Results ...........................................................................13-44 13.4.1 Results and Discussion....................................................................................13-44 13.4.1.1 Regional Benthic Community Structure.........................................13-44 13.4.1.2 Physical Habitat and Water Quality................................................13-48 13.4.1.3 Index of Biotic Integrity ..................................................................13-49 13.4.1.4 Seasonal and Annual Trend Analysis...............................................13-52 13.4.2 Summary and Conclusions..............................................................................13-55 13.5 Ambient Bay and Lagoon Monitoring...........................................................................13-56 13.6 Coastal Outfall Data.....................................................................................................13-78 13.6.1 Coastal Outfall Data Analysis Results for San Diego County..........................13-78 13.6.2 Coastal Lagoon Outfall Data Analysis Results for San Diego County.............13-86 13.7 Third Party Regional Data............................................................................................13-93 13.7.1 Surface Water Ambient Monitoring Program (SWAMP)................................13-93 13.7.2 Padre Dam Water Quality Monitoring Program ............................................13-94 13.7.2.1 Summary of Third Party Data Monitoring Locations......................13-94 13.7.2.2 Padre Dam Data Summary.............................................................13-97 13.7.3 Third Party Data Conclusions.........................................................................13-98 13.8 Regional Water Quality Priority Rating........................................................................13-98 14.0 CONCLUSIONS AND RECOMMENDATIONS.......................................................................14-1 14.1 Conclusions....................................................................................................................14-1 14.1.1 Wet Weather Monitoring Conclusions.............................................................14-1 14.1.2 Stream Bioassessment Conclusions..................................................................14-3 14.1.3 Ambient Bay and Lagoon Program Conclusions...............................................14-4 14.1.4 Watershed Assessment Conclusions................................................................14-5 14.1.4.1 Santa Margarita River Watershed Management Area.......................14-5 14.1.4.2 San Luis Rey River Watershed Management Area............................14-5 14.1.4.3 Carlsbad Watershed Management Area...........................................14-5 14.1.4.4 San Dieguito River Watershed Management Area ...........................14-6 14.1.4.5 Los Peñasquitos Creek Watershed Management Area....................14-7 14.1.4.6 Mission Bay Watershed Management Area......................................14-7 14.1.4.7 San Diego River Watershed Management Area ...............................14-7 14.1.4.8 San Diego Bay Watershed Management Area..................................14-8 14.1.4.9 Tijuana River Watershed Management Area....................................14-9 14.2 Program Review.............................................................................................................14-9 14.3 Recommendations .......................................................................................................14-12 14.3.1 2005-2006 Recommendations........................................................................14-12 14.3.2 2007-2010 Recommendations........................................................................14-14 14.3.2.1 Recommended 2008/2009 Program ..............................................14-17 14.3.2.2 Sampling Schedule ..........................................................................14-17 14.3.2.3 Consistency with SMC 2004 Document ........................................14-17 15.0 REFERENCES ....................................................................................................................15-1 Table of Contents 2004-2005 Urban Runoff Monitoring Report viii APPENDICES A Hydrographs B Stream Bioassessment Data C Scatterplots and Trend Data D Dry Weather Data Land Use and MS4 Type by Watershed E Attachment A - Coastal Storm Drain Monitoring F Attachment B - Toxic Hot Spots Monitoring G Long-Term Effectiveness Assessment Tables H Third Party Data I Response to Comments List of Tables 2004-2005 Urban Runoff Monitoring Report ix LIST OF TABLES 1-1. Analytical requirements for each type of monitoring site as specified in RWQCB Order 95-76 (Woodward-Clyde 1998)..............................................................................................................1-6 1-2. Wet-weather monitoring stations 1993-1994 through 2004-2005.................................................1-15 1-3. Analytical requirements for Mass Loading Stations 2004-2005.......................................................1-17 1-4. Additional constituents analyzed for Mass Loading Stations 2004-2005. ........................................1-18 1-5. Report Organization........................................................................................................................1-19 2-1. Rainfall statistics for San Diego International Airport (1948 through 1986)......................................2-6 2-2. Hydrologic Areas in the San Diego Region........................................................................................2-9 2-3. Reservoirs in the San Diego Region.................................................................................................2-12 2-4. Watershed Management Areas in the San Diego Hydrologic Region..............................................2-13 2-5. Watershed Acreages by Jurisdiction................................................................................................2-15 2-6. Land Use Distribution in San Diego Region (2000 Estimates).........................................................2-16 2-7. Land Use Acreage for Portions of the Watersheds in San Diego County (2000 Estimates)..........2-17 2-8. Planned Land Use of Vacant/Undeveloped Land for Watersheds Entirely Within the San Diego Region. ........................................................................................................................................2-17 2-9. Population Distribution in San Diego County (Census 2000). ........................................................2-18 2-10. 1990, 1997, and 2015 Population for Watersheds Entirely Within the San Diego Region............2-19 2-11. Rainfall Summary by Mass Loading Station for Monitored Storm Events......................................2-26 3-1. Analytical requirements for mass loading stations.............................................................................3-5 3-2. San Diego County: Stream Bioassessment Monitoring Sites. June 2001 to May 2005....................3-11 3-3. Bioassessment Metrics Used to Characterize BMI Communities...................................................3-17 3-4. Results of ANOVA on 1994 Newport Bay data..............................................................................3-20 3-5. Coastal embayments monitored in the Ambient Bay and Lagoon Monitoring Program.................3-21 3-6. Ambient Bay and Lagoon Phase I site locations...............................................................................3-23 3-7. Summary of Phase I field and analytical activities of the Ambient Bay and Lagoon Monitoring Program. .....................................................................................................................................3-25 3-8. Analytical parameters for the Ambient Bay and Lagoon Monitoring Program................................3-28 3-9. Summary of Phase II field and analytical activities of the Ambient Bay and Lagoon Monitoring Program. .....................................................................................................................................3-29 3-10. Sediment Effects Guideline Values.................................................................................................3-30 3-11. Water Quality Objectives for Wet Weather Monitoring at Mass Loading Stations.......................3-33 3-12. Toxicity Water Quality Objectives for wet weather monitoring at Mass Loading Stations.........3-35 3-13. Dry Weather Action Levels for 2002. ...........................................................................................3-36 3-14. Triad Definitions for San Diego Storm Water Monitoring Program. ............................................3-36 3-15. Tabular Decision Matrix – chemical, toxicity, and benthic assemblage data available (adapted from SMC Model Storm Water Monitoring Program, 2004). ....................................................3-37 3-16. Matrix of Findings. .........................................................................................................................3-39 3-17. Interim Criteria for Evaluating Mass Loading and Dry Weather Station Data...............................3-40 3-18. Summary of Water Quality Exceedance Scale...............................................................................3-43 3-19. Summary of MLS -Wet Weather Water Quality Exceedance Scale.............................................3-44 3-20. Summary of Wet Weather Benthic Alterations Scores. ................................................................3-44 3-21. Summary of Sediment Scoring Criteria. ........................................................................................3-45 3-22. Summary of ABLM Scoring Criteria. .............................................................................................3-45 3-23. Summary of Toxicity Scoring Criteria............................................................................................3-46 List of Tables 2004-2005 Urban Runoff Monitoring Report x 4-1. Beneficial uses within the Santa Margarita watershed.......................................................................4-1 4-2. Water bodies on the SWRCB 303(d) list in the Santa Margarita watershed.....................................4-3 4-3. Analytes measured at the Santa Margarita River mass loading station..............................................4-5 4-4. Santa Margarita River WMA 2004 dry weather exceedance matrix. ................................................4-8 4-5. Selected Biological Metrics and Physical Measures of the Santa Margarita River WMA. ................4-11 4-6. Santa Margarita River WMA Community Summary........................................................................4-12 4-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Santa Margarita River Estuary...............................................................................................................4-15 4-8. Summary of chemistry, toxicity, and benthic community structure in Santa Margarita River Estuary. .......................................................................................................................................4-15 4-9. Dominant infaunal species found in the Santa Margarita River Estuary during the 2004 ABLM Program. .....................................................................................................................................4-16 4-10. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Oceanside Harbor.......................................................................................................................4-18 4-11. Summary of chemistry, toxicity, and benthic community structure in Oceanside Harbor...........4-19 4-12. Dominant infaunal species found in Oceanside Harbor during the 2004 ABLM Program............4-20 4-13. Constituent exceedances in the Santa Margarita River WMA.......................................................4-22 4-14. Decision matrix results for Santa Margarita River WMA...............................................................4-24 4-15. Baseline Long-Term Effectiveness Assessment (BLTEA) ratings for the Santa Margarita River WMA...........................................................................................................................................4-25 5-1. Beneficial uses within the San Luis Rey watershed............................................................................5-3 5-2. Water bodies on the SWRCB 303(d) list in the San Luis Rey watershed..........................................5-3 5-3. Analytes measured at the San Luis Rey River mass loading station...................................................5-5 5-4. San Luis Rey WMA 2004 dry weather exceedance matrix................................................................5-8 5-5. Selected Biological Metrics and Physical Measures of the San Luis Rey River WMA. .....................5-11 5-6. San Luis Rey River WMA Community Summary.............................................................................5-12 5-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at San Luis Rey River Estuary.................................................................................................................5-15 5-8. Summary of chemistry, toxicity, and benthic community structure in San Luis Rey River Estuary. .......................................................................................................................................5-15 5-9. Dominant infaunal species found in the San Luis Rey River Estuary during the 2004 ABLM Program. .....................................................................................................................................5-16 5-10. Constituent exceedances in the San Luis Rey River WMA............................................................5-18 5-11. Decision matrix results for San Luis Rey River WMA....................................................................5-20 5-12. Baseline Long-Term Effectiveness Assessment (BLTEA) ratings for the San Luis Rey River WMA...........................................................................................................................................5-21 6-1. Beneficial uses within the Carlsbad watershed..................................................................................6-3 6-2. Water bodies on the SWRCB 303(d) list in the Carlsbad watershed................................................6-3 6-3. Analytes measured at the Agua Hedionda Creek mass loading station.............................................6-7 6-4. Analytes measured at the Escondido Creek mass loading station.....................................................6-9 6-5. Agua Hedionda 2004 dry weather Exceedance Matrix...................................................................6-12 6-6. Escondido Creek 2004 dry weather Exceedance Matrix................................................................6-15 6-7. Selected Biological Metrics and Physical Measures of the Carlsbad WMA. ....................................6-18 6-8. Carlsbad WMA Community Summary............................................................................................6-19 6-9. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Buena Vista Lagoon.....................................................................................................................6-23 6-10. Summary of chemistry, toxicity, and benthic community structure in Buena Vista Lagoon. ........6-23 List of Tables 2004-2005 Urban Runoff Monitoring Report xi 6-11. Dominant infaunal species found in Buena Vista Lagoon during the 2004 ABLM Program. .........6-25 6-12. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Agua Hedionda Lagoon...............................................................................................................6-27 6-13. Summary of chemistry, toxicity, and benthic community structure in Agua Hedionda Lagoon. ..6-27 6-14. Dominant infaunal species found in the Agua Hedionda Lagoon during the 2004 ABLM Program. .....................................................................................................................................6-28 6-15. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Batiquitos Lagoon........................................................................................................................6-31 6-16. Summary of chemistry, toxicity, and benthic community structure in Batiquitos Lagoon............6-31 6-17. Dominant infaunal species found in the Batiquitos Lagoon during the 2004 ABLM Program.......6-32 6-18. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at San Elijo Lagoon.................................................................................................................................6-34 6-19. Summary of chemistry, toxicity, and benthic community structure in San Elijo Lagoon...............6-35 6-20. Dominant infaunal species found in the San Elijo Lagoon during the 2004 ABLM Program. ........6-36 6-21. Constituent exceedances in Agua Hedionda Creek......................................................................6-39 6-22. Decision matrix result for Agua Hedionda Creek.........................................................................6-41 6-23. Constituents of concern measured at Escondido Creek...............................................................6-42 6-24. Decision matrix results for Escondido Creek................................................................................6-44 6-25. Baseline Long-Term Effectiveness Assessment (BLTEA) ratings for the Carlsbad WMA.............6-45 7-1. Beneficial uses within the San Dieguito River watershed..................................................................7-1 7-2. Water bodies on the SWRCB 303(d) list in the San Dieguito River watershed. ...............................7-3 7-3. Analytes measured at the San Dieguito River mass loading station...................................................7-5 7-3. Continued..........................................................................................................................................7-6 7-4. San Dieguito River WMA 2004 dry weather exceedance matrix......................................................7-8 7-5. Selected Biological Metrics and Physical Measures of the San Dieguito River WMA......................7-11 7-6. San Dieguito River WMA Community Summary.............................................................................7-12 7-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at San Dieguito Lagoon..........................................................................................................................7-14 7-8. Summary of chemistry, toxicity, and benthic community structure in............................................7-15 San Dieguito Lagoon. ...............................................................................................................................7-15 7-9. Dominant infaunal species found in the San Dieguito Lagoon during the 2004 ABLM Program. ...7-16 7-10. Constituent exceedances in the San Dieguito River WMA. ..........................................................7-17 7-11. Decision matrix results for San Dieguito River WMA. ..................................................................7-19 7-12. Baseline Long-Term Effectiveness Assessment (BLTEA) ratings for the San Dieguito River WMA...........................................................................................................................................7-20 8-1. Beneficial uses within the Los Peñasquitos watershed......................................................................8-1 8-2. Water bodies on the SWRCB 303(d) list in the Los Peñasquitos watershed....................................8-3 8-3. Analytes measured at the Los Peñasquitos Creek mass loading station............................................8-5 8-4. Los Peñasquitos WMA 2004 dry weather exceedance matrix..........................................................8-8 8-5. Selected Biological Metrics and Physical Measures of the Los Peñasquitos WMA..........................8-12 8-6. Los Peñasquitos WMA Community Summary.................................................................................8-13 8-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Los Peñasquitos Lagoon. ...................................................................................................................8-15 8-8. Summary of chemistry, toxicity, and benthic community structure in Los Peñasquitos Lagoon. ...8-16 8-9. Dominant infaunal species found in the Los Peñasquitos Lagoon during the 2004 ABLM Program. .....................................................................................................................................8-17 8-10. Constituent exceedances in the Los Peñasquitos WMA. ..............................................................8-19 List of Tables 2004-2005 Urban Runoff Monitoring Report xii 8-11. Decision matrix results for the Los Peñasquitos WMA.................................................................8-19 8-12. Baseline Long-Term Effectiveness Assessment (BLTEA) ratings for the Los Peñasquitos WMA...........................................................................................................................................8-21 9-1. Beneficial uses within the Mission Bay watershed (Rose and Tecolote Creeks)...............................9-3 9-2. Water bodies on the SWRCB 303(d) List in the Mission Bay watershed..........................................9-3 9-3. Analytes measured at the Tecolote Creek mass loading station.......................................................9-5 9-4. Mission Bay WMA 2004 dry weather exceedance matrix...............................................................9-10 9-5. Selected Biological Metrics and Physical Measures of the Mission Bay WMA.................................9-13 9-6. Mission Bay WMA Community Summary........................................................................................9-14 9-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Rose Creek and Tecolote Creek outfalls in Mission Bay.....................................................................9-16 9-8. Summary of chemistry, toxicity, and benthic community structure in Mission Bay........................9-17 9-9. Dominant infaunal species found in the Mission Bay during the 2004 ABLM Program...................9-18 9-10. Constituent exceedances in the Mission Bay WMA......................................................................9-20 9-11. Decision matrix results for the Mission Bay WMA........................................................................9-22 9-12. Baseline Long-Term Effectiveness Assessment (BLTEA) ratings for the Mission Bay WMA. .......9-23 10-1. Beneficial uses within the San Diego River watershed..................................................................10-3 10-2. Water bodies on the SWRCB 303(d) list in the San Diego River watershed.................................10-3 10-3. Analytes measured at the San Diego River mass loading station...................................................10-5 10-4. San Diego River WMA 2004 dry weather exceedance matrix......................................................10-8 10-5. Selected Biological Metrics and Physical Measures of the San Diego River WMA......................10-12 10-6. San Diego River WMA Community Summary.............................................................................10-13 10-7. Constituent exceedances in the San Diego River WMA..............................................................10-15 10-8. Decision matrix results for San Diego River WMA. ....................................................................10-17 10-9. Baseline Long-Term Effectiveness Assessment (BLTEA) ratings for the San Diego River WMA.........................................................................................................................................10-18 11-1. Beneficial uses within the Pueblo San Diego watershed. ..............................................................11-3 11-2. Water bodies on the SWRCB 303(d) list in the Pueblo San Diego watershed..............................11-4 11-3. Beneficial uses within the Sweetwater watershed. .......................................................................11-5 11-4. Water bodies on the SWRCB 303(d) list in the Sweetwater watershed.......................................11-5 11-5. Beneficial uses within the Otay watershed....................................................................................11-7 11-6. Water bodies on the SWRCB 303(d) list in the Otay watershed..................................................11-7 11-7. Analytes measured at the Chollas Creek mass loading station......................................................11-9 11-8. Analytes measured at the Sweetwater River mass loading station..............................................11-12 11-9. Pueblo San Diego 2004 dry weather exceedance matrix............................................................11-17 11-10. Sweetwater River 2004 dry weather exceedance matrix.........................................................11-19 11-11. Selected Biological Metrics and Physical Measures of the San Diego Bay WMA.......................11-21 11-12. San Diego Bay WMA Community Summary. ............................................................................11-22 11-13. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Sweetwater River Estuary.........................................................................................................11-25 11-14. Summary of chemistry, toxicity, and benthic community structure in Sweetwater River Estuary. .....................................................................................................................................11-25 11-15. Dominant infaunal species found in the Sweetwater River Estuary during the 2004 ABLM Program. ...................................................................................................................................11-26 11-16. Constituent exceedances in the Chollas sub-watershed...........................................................11-29 11-17. Constituent exceedances in the Sweetwater watershed..........................................................11-32 List of Tables 2004-2005 Urban Runoff Monitoring Report xiii 11-18. Decision matrix results for the Chollas Sub-watershed............................................................11-34 11-19. Decision matrix results for the Sweetwater Watershed...........................................................11-34 11-20. Baseline Long-Term Effectiveness Assessment (BLTEA) ratings for the San Diego Bay WMA.........................................................................................................................................11-35 12-1. Beneficial uses within the Tijuana River watershed.......................................................................12-3 12-2. Water bodies on the SWRCB 303(d) list in the Tijuana River watershed.....................................12-4 12-3. Analytes measured at the Tijuana River mass loading station........................................................12-5 12-4. Tijuana River WMA 2004 dry weather exceedance matrix...........................................................12-9 12-5. Selected Biological Metrics and Physical Measures of the Tijuana River WMA...........................12-12 12-6. Tijuana River WMA Community Summary..................................................................................12-13 12-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Tijuana River Estuary.................................................................................................................12-16 12-8. Summary of chemistry, toxicity, and benthic community structure in the Tijuana River Estuary ......................................................................................................................................12-17 12-9. Dominant infaunal species found in Tijuana River Estuary during the 2004 ABLM Program......12-17 12-10. Constituent exceedances in the Tijuana River WMA................................................................12-20 12-11. Decision matrix results for Tijuana River watershed.................................................................12-22 12-12. Baseline Long-Term Effectiveness Assessment (BLTEA) ratings for the Tijuana River WMA. .12-23 13-1. Results of Wet Weather Monitoring in 2004-2005........................................................................13-2 13-2. Multiple regression results...........................................................................................................13-25 13-3. Multiple regression results for 2001-02, 2002-03, 2003-04, and 2004-05 combined.................13-27 13-4. EMC Input Parameters for each Land Use Category, 2003-2004...............................................13-31 13-5. Discrete Water Quality Results at Agua Hedionda Creek, March 22, 2005...............................13-37 13-6. Dry Weather Exceedance Matrix (2004). ...................................................................................13-39 13-7. COC by land use category (2004 dry weather monitoring data)................................................13-40 13-8. COC ranking by land use category (2002 – 2004 dry weather monitoring data).......................13-41 13-9. COC by MS4 conveyance type (2004 dry weather monitoring data).........................................13-42 13-10. Bioassessment Metrics Used to Characterize BMI Communities.............................................13-45 13-11. Index of Biotic Integrity Scoring Ranges. ...................................................................................13-50 13-12. Coastal embayments monitored in the summer of 2004 for the Ambient Bay and Lagoon Monitoring Program..................................................................................................................13-56 13-13. Ambient Bay and Lagoon Phase I TOC and grain size results...................................................13-59 13-14. Concentration of COCs in sediment for each coastal embayment compared to sediment quality guidelines (ERL and ERM)..............................................................................................13-62 13-15. Results of sediment toxicity tests for each embayment in the ABLM Program. .......................13-66 13-16. Summary of major benthic infauna classifications collected from sediments in the 12 coastal embayments monitored in the ABLM Program........................................................................13-67 13-17. Summary of the most abundant and most common taxa collected at all 12 coastal embayments monitored in the ABLM Program........................................................................13-67 13-18. Indices of community structure in Ambient Bay and Lagoon Monitoring Program from samples collected in the summer of 2004. Values represent the mean of three sites per embayment unless otherwise noted.........................................................................................13-68 13-19. Chemistry and toxicity results and the associated relative ranks for each embayment.............13-73 13-20. Benthic community structure indices results and relative ranking for each embayment..........13-74 13-21. Relative rankings based on chemistry, toxicity, and benthic community structure for each embayment. ..............................................................................................................................13-75 13-22. Enterococci water quality objectives for saltwater in REC-1 waterbodies...............................13-89 List of Tables 2004-2005 Urban Runoff Monitoring Report xiv 13-23. Padre Dam Water Quality Monitoring results...........................................................................13-95 13-24. Number of Padre Dam field and analytical samples by station (2004)......................................13-97 14-1. Mass Loading Station Persistent Wet Weather Constituents and Trends.....................................14-2 14-2. Recommended actions from the triad assessment......................................................................14-13 List of Figures 2004-2005 Urban Runoff Monitoring Report xv LIST OF FIGURES 1-1. Wet-weather monitoring stations for 1993 through 2005..............................................................1-16 2-1. San Diego County Geology. ..............................................................................................................2-1 2-2. San Diego - Lindberg Field Monthly Precipitation Summary 2004-2005. .........................................2-5 2-3. San Diego - Lindberg Field Storm Season Rainfall 1960 to 2004.......................................................2-6 2-4. San Diego Watersheds.......................................................................................................................2-7 2-5. San Diego Watershed Management Areas........................................................................................2-8 2-6. Major Ground Water Basins in San Diego County..........................................................................2-10 2-7. San Diego Reservoirs.......................................................................................................................2-11 2-8. Watershed Areas of the San Diego Hydrologic Region...................................................................2-14 2-9. Land Ownership in San Diego Watersheds.....................................................................................2-14 2-10. Land Use in San Diego Watersheds...............................................................................................2-16 2-11. Population Per Acre for Watersheds Entirely within the San Diego Region.................................2-19 2-12. Population for Watershed Management Areas Entirely Within the San Diego Region.................2-20 2-13. Mass Loading Station Locations.....................................................................................................2-21 2-14. Contributing Runoff Land Use Acreages by Mass Loading Station................................................2-22 2-15. Contributing Runoff Land Use Percentages by Mass Loading Station...........................................2-23 2-16. San Diego County Daily Rainfall Totals..........................................................................................2-24 2-17. San Diego County Daily Rainfall Distribution................................................................................2-25 3-1. Stream Bioassessment Sites Sampled October 2004 and May 2005...............................................3-14 3-2. Map of coastal embayments monitored in the Ambient Bay and Lagoon Monitoring Program. ....3-22 3-3. Water quality priority rating methodology......................................................................................3-42 4-1. Santa Margarita River Watershed Management Area........................................................................4-2 4-2. Santa Margarita River water quality ratios.........................................................................................4-8 4-3. Santa Margarita River WMA dry weather exceedance map..............................................................4-9 4-4. Map of Phase I site locations in Santa Margarita River Estuary........................................................4-14 4-5. Relative rankings for sediment in Santa Margarita River Estuary.....................................................4-17 4-6. Map of Phase I site locations in Oceanside Harbor.........................................................................4-18 4-7. Relative rankings for sediment in Oceanside Harbor......................................................................4-20 4-8. Stacked bar chart of the number of wetweather exceedances of constituent groups in Santa Margarita River............................................................................................................................4-23 5-1. San Luis Rey River Watershed Management Area.............................................................................5-2 5-2. San Luis Rey River water quality ratios..............................................................................................5-8 5-3. San Luis Rey WMA dry weather exceedance map............................................................................5-9 5-4. Map of Phase I site locations in San Luis Rey River Estuary.............................................................5-14 5-5. Relative Rankings for sediment in San Luis Rey River Estuary.........................................................5-17 5-6. Stacked bar chart of the number of wet weather exceedances of constituent groups in San Luis Rey River..............................................................................................................................5-20 6-1. Carlsbad Watershed Management Area............................................................................................6-2 6-2. Agua Hedionda Creek water quality ratios. ....................................................................................6-12 6-3. Carlsbad WMA dry weather exceedance map................................................................................6-14 6-4. Escondido Creek water quality ratios. ............................................................................................6-15 6-5. Map of Phase I site locations in Buena Vista Lagoon .......................................................................6-22 List of Figures 2004-2005 Urban Runoff Monitoring Report xvi 6-6. Relative rankings for sediment in Buena Vista Lagoon. ...................................................................6-25 6-7. Map of Phase I site locations in Agua Hedionda Lagoon .................................................................6-26 6-8. Relative rankings for sediment in Agua Hedionda Lagoon...............................................................6-29 6-9. Map of Phase I site locations in Batiquitos Lagoon..........................................................................6-30 6-10. Relative rankings for sediment in Batiquitos Lagoon.....................................................................6-33 6-11. Map of Phase I site locations in San Elijo Lagoon...........................................................................6-34 6-12. Relative rankings for sediment in San Elijo Lagoon........................................................................6-36 6-13. Stacked bar chart of the number of wet weather exceedances of constituent groups in Agua Hedionda Creek..........................................................................................................................6-40 6-14. Stacked bar chart of the number of wet weather exceedances of constituent groups in Escondido Creek.........................................................................................................................6-43 7-1. San Dieguito River Watershed Management Area. ...........................................................................7-2 7-2. San Dieguito River water quality ratios..............................................................................................7-8 7-3. San Dieguito River WMA dry weather exceedance map. .................................................................7-9 7-4. Map of Phase I site locations in San Dieguito Lagoon......................................................................7-13 7-5. Relative rankings for sediment in San Dieguito Lagoon...................................................................7-16 7-6. Stacked bar chart of the number of wet weather exceedances of constituent groups in San Dieguito River. ............................................................................................................................7-19 8-1. Los Peñasquitos Watershed Management Area................................................................................8-2 8-2. Los Peñasquitos Creek water quality ratios......................................................................................8-8 8-3. Los Peñasquitos WMA dry weather exceedance map....................................................................8-10 8-4. Map of Phase I site locations in Los Peñasquitos Lagoon ................................................................8-14 8-5. Relative rankings for sediment in the Los Peñasquitos Lagoon.......................................................8-17 8-6. Stacked bar chart of the number of wet weather exceedances of constituent groups in Los Peñasquitos Creek......................................................................................................................8-20 9-1. Mission Bay Watershed Management Area.......................................................................................9-2 9-2. Tecolote Creek water quality ratios..................................................................................................9-9 9-3. Mission Bay WMA dry weather exceedance map...........................................................................9-11 9-4. Map of Phase I site locations in Mission Bay....................................................................................9-15 9-5. Relative rankings for sediment in Mission Bay.................................................................................9-18 9-6. Stacked bar chart of the number of wet weather exceedances of constituent groups in Mission Bay WMA....................................................................................................................................9-21 10-1. San Diego River Watershed Management Area. ...........................................................................10-2 10-2. San Diego River water quality ratios..............................................................................................10-8 10-3. San Diego River WMA dry weather exceedance map. ...............................................................10-10 10-4. Stacked bar chart of the number of wet weather exceedances of constituent groups in San Diego River. ..............................................................................................................................10-16 11-1. San Diego Bay Watershed Management Area...............................................................................11-2 11-2. Chollas Creek water quality ratios..............................................................................................11-16 11-3. San Diego Bay WMA dry weather exceedance map...................................................................11-18 11-4. Sweetwater River water quality ratios. .......................................................................................11-19 11-5. Map of Phase I site locations in Sweetwater River Estuary. Sites in red were selected for Phase II assessment...................................................................................................................11-24 11-6. Relative rankings for sediment in Sweetwater River...................................................................11-27 List of Figures 2004-2005 Urban Runoff Monitoring Report xvii 11-7. Stacked bar chart of the number of wet weather exceedances of constituent groups in Chollas Creek. ..........................................................................................................................11-30 11-8. Stacked bar chart of the number of wet weather exceedances of constituent groups in Sweetwater watershed.............................................................................................................11-33 12-1. Tijuana River Watershed Management Area.................................................................................12-2 12-2. Tijuana River water quality ratios..................................................................................................12-9 12-3. Tijuana River WMA dry weather exceedance map.....................................................................12-10 12-4. Map of Phase I site locations in Tijuana River Estuary.................................................................12-15 12-5. Relative rankings for sediment in Tijuana River Estuary..............................................................12-18 12-6. Stacked bar chart of the number of wet weather exceedances of constituent groups in Tijuana River..............................................................................................................................12-21 13-1. Regional Comparison of Mean Annual Concentration to WQO Ratio – Conventionals – Total Suspended Solids and Total Dissolved Solids..............................................................................13-7 13-2. Regional Comparison of Significant Trends – Conventionals – Total Suspended Solids, Turbidity and Conductivity. ........................................................................................................13-8 13-3. Regional Comparison of Mean Annual Concentration to WQO Ratio – Nutrients – Ammonia and Total Phosphorus...............................................................................................................13-10 13-4. Regional Comparison of Significant Trends – Nutrients – Nitrate and Total Phosphorus..........13-11 13-5. Regional Comparison of Mean Annual Concentration to WQO Ratio – Pesticides – Diazinon and Chlorpyrifos........................................................................................................................13-12 13-6. Regional Comparison of Significant Trends – Pesticides – Diazinon...........................................13-13 13-7. Regional Comparison of Mean Annual Concentration to WQO Ratio – Metals – Copper and Zinc...........................................................................................................................................13-14 13-8. Regional Comparison of Significant Trends – Metals – Total Lead. ............................................13-15 13-9. Regional Comparison of Mean Annual Concentration to WQO Ratio – Toxicity – Ceriodaphnia Survival and Reproduction..................................................................................13-16 13-10. Regional Comparison of Mean Annual Concentration to WQO Ratio – Bacteria – Fecal Coliform....................................................................................................................................13-17 13-11. Regional Comparison of Significant Trends – Bacteria – Enterococcus and Fecal Coliform.....13-17 13-12. Results of MLS Comparisons by Analysis of Variance (ANOVA). .............................................13-20 13-13. Results of Cluster Analysis for Wet Weather Data....................................................................13-22 13-14. Relationships of Ceriodaphnia dubia acute survival with significant regressors from multiple regression analysis.....................................................................................................................13-25 13-15. Relationships of Ceriodaphnia dubia reproduction with significant regressors from multiple regression analysis.....................................................................................................................13-26 13-16. Relationships of Ceriodaphnia dubia acute survival with significant regressors from multiple regression analysis. Dashed line shows literature threshold.....................................................13-27 13-17. Relationships of Ceriodaphnia dubia chronic survival with significant regressors from multiple regression analysis. Dashed line shows literature threshold.......................................13-28 13-18. Relationships of Ceriodaphnia dubia reproduction with significant regressors from multiple regression analysis. Dashed line shows literature threshold.....................................................13-29 13-19. GIS data layer input into the EMC model..................................................................................13-33 13-20. Monitored vs. Modeled Event Mean Concentration Values......................................................13-35 13-21. Hydrograph of Constituents during the March 22, 2005 storm event......................................13-37 13-22. Monitoring sites with analytes above the action level by conveyance type...............................13-43 13-23. Index of Biotic Integrity Scores for San Diego County Bioassessment Sites. October 2004...13-51 13-24. Index of Biotic Integrity Scores for San Diego County Bioassessment Sites.............................13-52 List of Figures 2004-2005 Urban Runoff Monitoring Report xviii 13-25. Index of biotic integrity trends for San Diego County watersheds. May 2001 – May 2005.....13-53 13-26. Whisker box plot of all San Diego County bioassessment monitoring sites, May 2001-May 2005. .........................................................................................................................................13-54 13-27. Map of coastal embayments sampled in the summer of 2004 for the Ambient Bay and Lagoon Monitoring Program.....................................................................................................13-57 13-28. Mean percent fines and TOC content of sediment at ABLM Program embayments. ..............13-60 13-29. Relationship between percent fines and TOC content.............................................................13-60 13-30. Mean ERM quotients by embayment. Bars below the red line have a low probability of effects on biota (from Long et al. 1998)....................................................................................13-63 13-31. Mean ERM-Q values for each embayment versus TOC (A) and grain size (B) and mean ERM-Q rank for each embayment versus the TOC and grain size summed rank (C).............13-65 13-32. Taxa Richness among embayments...........................................................................................13-68 13-33. Taxa Abundance among embayments.......................................................................................13-69 13-34. Shannon Weiner Diversity Index among embayments..............................................................13-69 13-35. Taxa Evenness among embayments..........................................................................................13-69 13-36. Taxa Dominance among embayments. .....................................................................................13-70 13-37. Results of cluster analyses for coastal embayments and benthic taxa relative abundance........13-71 13-38. Relative ranking correlations between toxicity and chemistry (A), benthic community and chemistry (B), and benthic community and toxicity (C)...........................................................13-76 13-39. Relative ranking comparison between the 2003 and 2004 ABLM Programs............................13-77 13-40. Total coliform at coastal outfall receiving water stations (2004-05). ........................................13-80 13-41. Fecal coliform at coastal outfall receiving water stations (2004-05)..........................................13-81 13-42. Enterococcus at coastal outfall receiving water stations (2004-05). .........................................13-82 13-43. Total coliform at coastal storm drain outfalls (2004-05)...........................................................13-83 13-44. Fecal coliform at coastal storm drain outfalls (2004-05). ..........................................................13-84 13-45. Enterococcus at coastal storm drain outfalls (2004-05)............................................................13-85 13-46. Total coliform at coastal lagoon outfall receiving water stations (2004-05)..............................13-87 13-47. Fecal coliform at coastal lagoon outfall receiving water stations (2004-05)..............................13-88 13-48. Enterococcus at coastal lagoon outfall receiving water stations (2004-05)...............................13-89 13-49. Total coliform at coastal lagoon storm drain outfall stations (2004-05)....................................13-90 13-50. Fecal coliform at coastal lagoon storm drain outfall stations (2004-05)....................................13-91 13-51. Enterococcus at coastal lagoon storm drain outfall stations (2004-05).....................................13-92 13-52. Watershed Water Quality Priority Rating for Heavy Metals. ..................................................13-101 13-53. Sub-Watershed Water Quality Priority Rating for San Diego Bay WMA - Heavy Metals. .....13-102 13-54. Watershed Water Quality Priority Rating for Organics...........................................................13-103 13-55. Watershed Water Quality Priority Rating for Oil and Grease.................................................13-105 13-56. Watershed Water Quality Priority Rating for Sediment..........................................................13-106 13-57. Watershed Water Quality Priority Rating for Pesticides.........................................................13-107 13-58. Watershed Water Quality Priority Rating for Nutrients..........................................................13-108 13-59. Watershed Water Quality Priority Rating for Gross Pollutants...............................................13-109 13-60. Watershed Water Quality Priority Rating for Bacteria/Pathogens..........................................13-111 13-61. Sub-Watershed Water Quality Priority Rating for Tijuana WMA – Bacteria...........................13-112 14-1. Recommended Monitoring Stations in an Idealized Watershed..................................................14-15 List of Acronyms and Abbreviations 2004-2005 Urban Runoff Monitoring Report xix LIST OF ACRONYMS AND ABBREVIATIONS ABLM Ambient Bay and Lagoon Monitoring Program ADCP Acoustic Doppler Current Profiler AH1 Agua Hedionda Creek AHC Agua Hedionda Creek ANOVA analysis of variance BMI benthic macroinvertebrates BMP best management practices BOD biochemical oxygen demand BPTCP Bay Protection and Toxic Cleanup Program BVL Buena Vista Lagoon BWQMP Binational Water Quality Monitoring Program CC Chollas Creek CDFG California Department of Fish and Game COC constituents of concern COD chemical oxygen demand CSBP California Stream Bioassessment Procedure CWA U.S. Clean Water Act DO dissolved oxygen DOC dissolved organic carbon DWS dry weather sampling EC Escondido Creek EDTA ethylenediaminetetraacetic acid ELISA enzyme-linked immunosorbant assay EMC event mean concentrations EPA U.S. Environmental Protection Agency EPT Ephemeroptera, Plecoptera, and Trichoptera ERL effect range low ERM effect range median ERM-Q effect range median quotient FFG functional feeding groups FHWA Federal Highway Administration GIS geographic information system GPS global positioning system HA hydrologic areas HSA hydrologic subareas HU hydrologic units IBI Index of Biotic Integrity IC25 concentration that causes 25 percent inhibition in growth IC50 concentration that causes 50 percent inhibition in growth ICID Illicit connections and illegal discharges ISWP Inland Surface Waters Plan LC25 concentration that causes 25 percent mortality LC50 concentration that causes 50 percent mortality MBAS Methylene Blue Active Substances MH macrophyte herbivore MLLW mean lower low water List of Acronyms and Abbreviations 2004-2005 Urban Runoff Monitoring Report xx MLS mass loading stations MPN most probable number MS4 municipal separate storm sewers MSE mean square error NOAA National Oceanic and Atmospheric Administration NOEC No Observed Effect Concentration NPDES National Pollutant Discharge Elimination System NTU nephelometric turbidity units NURP Nationwide Urban Runoff Program O&G Oil and Grease OM omnivore OR Otay River PAH polycyclic aromatic hydrocarbons PC Peñasquitos Creek PCA principal component analysis PCB polychlorinated biphenyls PH piercer herbivore POTW Publicly Owned Treatment Works RSB Rapid Stream Bioassessment RWQCB Regional Water Quality Control Board SANDAG San Diego Association of Governments SCCWRP Southern California Coastal Waters Research Project SD5 Tecolote Creek SD8 Chollas Creek SDC San Dieguito Creek SDG&E San Diego Gas & Electric SDR San Diego River SLR San Luis Rey River SMC Stormwater Monitoring Coalition SME Santa Margarita Estuary SMR Santa Margarita River SR Sweetwater River SWMM Storm Water Management Model TC Tecolote Creek TDS total dissolved solids THSWG Toxic Hot Spot Work Group TIE Toxicity Identification Evaluation TJR Tijuana River TKN Total Kjeldahl Nitrogen TMDL Total Maximum Daily Loads TOC total organic carbon TSS total suspended solids TU toxic units TUa toxic units acute TUc toxic units chronic TV tolerance values URMP Urban Runoff Management Plans USEPA U.S. Environmental Protection Agency List of Acronyms and Abbreviations 2004-2005 Urban Runoff Monitoring Report xxi USGS U.S. Geological Survey WER water effects ratio WMA watershed management areas XY xylophages List of Contributors 2004-2005 Urban Runoff Monitoring Report xxii LIST OF CONTRIBUTORS Principal Investigator/ Technical Advisor Lisa Marie Kay Project Manager David Pohl Assistant Project Manager Chris Warn Wet Season Monitoring Task Leader Chris Warn and Tommy Wells Field Monitoring Team Mike Anghera, Nicole Apel, Laurence Campagna, Melanie Craig, Carla Cummings, Rosabel Dias, Ryan Ericson, Michelle Evans, Bruce Ferguson, Steve Gruber, Amy Hamilton, Sheila Holt, Jamie Hultman, Bill Isham, Grover Jeane, Dan McCoy, Damon Owen, Brian Riley, Kevin Sampson, Lucretia Shatzer, Tracy Schuh, Susie Watts, Alison Witheridge, Satomi Yonemasu, Jeff Yu Bioassay Emma Cook, Rosabel Dias, Tom Gerlinger, Brian Hester, Amy Margolis, Robert Marshall, Dan McCoy, Chris Osuch, Dan Sowersby, Tracy Staker, Jay Word Chemistry EnviroMatrix Analytical, Inc. Microbiology Larissa Aumand, Rosabel Dias, Lucretia Shatzer Quality Assurance Oversight Lin Craft, Rosabel Dias Data Management Susie Watts, Ryan Ericson, Bruce Ferguson Stream Bioassessment Monitoring Task Leader Bill Isham Field Surveys Chris Clark, Michelle Evans, Jamie Hultman, Bill Isham, Damon Owen, Dan Tracy Schuh, Kasey Skrivseth, Sowersby Sample Processing Michelle Evans, Jamie Hultman, Bill Isham, Andrew Lovell, Damon Owen, Tracy Schuh Taxonomy Michelle Evans, Alison Witheridge (Crustacea), Sheila Holt (Mollusca), Bill Isham (Insecta and other Phyla) Data Management Bruce Ferguson, Bill Isham, Samantha Leskie, Susie Watts List of Contributors 2004-2005 Urban Runoff Monitoring Report xxiii Ambient Bay and Lagoon Program Task Leader Steve Gruber Lagoon Sampling Team Laurence Campagna, Steve Gruber, Amy Hamilton, Grover Jeane, Andrew Martin, Dan McCoy, Brian Riley, Chris Warn, Alison Witheridge Weston Laboratory Analysis Michelle Evans, Laurence Campagna, Amy Hamilton, Sheila Holt, Tracy Schuh, Alison Witheridge, Satomi Yonemasu Data Management Ryan Ericson, Bruce Ferguson, Susie Watts Watershed Assessments Authors Amy Hamilton, Cathy Hartman, Dave Renfrew Annual Report Report Authors Mike Anghera, Melanie Craig, Ryan Ericson, Jayna Ericson, Amy Hamilton, Brian Hester, Bill Isham, Lisa Marie Kay, David Pohl, Dave Renfrew, Chris Warn, Susie Watts, Tommy Wells Data Management Bruce Ferguson, Samantha Leskie, Susie Watts Modeling Bruce Ferguson Graphics Bruce Ferguson, Samantha Leskie, Michelle Patzius Report Production Valerie Arsenault, Teri Blackburn, Gwen Chavez, Michelle Patzius Editors Amy Hamilton, Lisa Kay, Chris Warn EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-1 ES.1 Introduction This document presents the results of the 2004-2005 municipal urban runoff monitoring conducted by Weston Solutions, Inc. (formerly MEC Analytical Systems, Inc-Weston and referred to as Weston) on behalf of the San Diego County Municipal Copermittees identified as dischargers of urban runoff in Order No. 2001-01 of the San Diego Regional Water Quality Control Board (RWQCB). This report fulfills the requirements of Order No. 2001-01 Attachment B, IV. Submittal of Receiving Waters Monitoring Requirements for Long-term Mass Loading Monitoring; Urban Stream Bioassessment Monitoring; Ambient Bay and Lagoon Monitoring, and Coastal Receiving Water Monitoring. A general overview of coastal storm drain outfall monitoring is provided in Section 13. Coastal storm drain outfall monitoring and San Diego Bay toxic hotspots monitoring, also required in Attachment B of Order 2001-01, (carried out by the appropriate jurisdictions and not conducted by Weston) are included as attachments to this document. This report discusses activities and findings comprised of the following: ♦ Chemical and toxicity testing of storm water runoff from 11 mass loading stations located within major watersheds of the County of San Diego. ♦ Rapid stream bioassessments at 27 stations in Fall 2004 and Spring 2005. ♦ Phase l and ll results of Ambient Bay and Lagoon monitoring at 12 coastal embayments. ♦ Dry weather, coastal outfall, and (limited) third party data as it relates to watershed water quality assessment. The main objectives of this monitoring program are to comply with NPDES Order 2001-01 and determine the ecological health of receiving waters in the region based on chemical, physical, and biological evidence. ES.2 Methods ES.2.1 Storm Water Methods Mass loading stations were located at the base of each selected watershed as far downstream as possible in each watershed and upstream of any tidal influence. Mass loading stations for this season were located along the Santa Margarita River (by Camp Pendleton), San Luis Rey River, Agua Hedionda Creek, Escondido Creek, San Dieguito River, Peñasquitos Creek, Tecolote Creek, San Diego River, Chollas Creek, Sweetwater River, and Tijuana River. Three storm events were monitored during the 2004-2005 wet-weather monitoring season at each mass loading station with the exception of the Santa Margarita River which was not sampled by Navy personnel due to equipment loss. ES.2.1.1 Stream Flow Rating During storms, the flow rate at each of the monitoring sites was determined by water velocity and stream stage (water level) sensors that are typically secured to the bottom of the channel. However, to better quantify flow rates and produce a more complete rating curve, each of the streams was also assessed using the classical stream rating method developed by the U.S. Geological Survey. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-2 ES.2.1.2 Storm Water Constituents Storm water samples were analyzed for conventional chemical constituents, total and dissolved metals (antimony, arsenic, cadmium, chromium, copper, lead, nickel, selenium, and zinc), organophosphate pesticides (Diazinon and Chlorpyrifos), and toxicity to bioassay test organisms. These constituent(s) of concern (COC) were measured from flow-weighted composite samples. Grab samples were used to measure some of the general physical parameters (pH, conductivity, biochemical oxygen demand, and oil and grease) and bacterial indicators (total coliform, fecal coliform, and enterococcus). ES.2.1.3 Toxicity Testing Toxicity testing was performed to assess the potential toxicity of storm water runoff at mass loading stations. Freshwater species used in chronic tests included a freshwater cladoceran (Ceriodaphnia dubia), acute tests with a freshwater amphipod (Hyalella azteca), and chronic tests with a freshwater alga (Selenastrum capricornutum). ES.2.2 Stream Bioassessment Monitoring Weston conducted stream bioassessments pursuant to RWQCB Order No. 2001-01 to assess the ecological health of the watershed units in San Diego County. The assessments were undertaken utilizing a protocol that samples and analyzes populations of benthic macroinvertebrates. A total of 27 different stream monitoring reaches were assessed in San Diego County in the surveys of October 2004 and May 2005. Four of these sites were considered to represent reference conditions. The stream bioassessment monitoring includes sampling and identification of benthic macroinvertebrates present, assessment of the physical habitat of the stream, and water quality measurements, including water temperature, specific conductance, pH, dissolved oxygen, and chlorophyll. ES.2.3 Ambient Bay and Lagoon Monitoring Under the NPDES permit granted to the County of San Diego by the RWQCB, the Copermittees are required to develop and implement a program to assess the overall health of the receiving waters and monitor the impact of urban runoff on ambient receiving water quality. To implement the Ambient Bay and Lagoon Monitoring Program (ABLM), evaluations of sediment chemistry, sediment toxicity, and ecological community (benthic infauna) structure in 12 coastal embayments in San Diego County were monitored. The data assessed in this report were from samples collected in the summer of 2004. The program was conducted in two phases: • Phase I – Contaminant Targeting: three areas in each embayment with the finest grain size and highest total organic carbon (TOC) concentration were identified using a stratified random design. • Phase II – Sediment Assessment: the areas identified in Phase I were assessed using the same “triad” approach that is being utilized for the storm water runoff program: chemistry, toxicity, and biology of the sediments. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-3 ES.2.4 Watershed Management Area Assessment Methods The watershed assessment included an identification and prioritization of COC based upon the prioritization system developed in the interim guidance document “Watershed Data Assessment Framework” (June 2004). Wet weather results were compared to water quality objectives to identify COC that were above criteria and persistently occurred within the watershed. Dry weather information was assessed from locations upstream of the mass loading stations and compared to wet weather constituents of concern. Toxicity was evaluated for persistence in each watershed and the triad data assessment approach was applied to determine if Toxicity Identification Evaluations were needed in the watersheds. Frequency of occurrence within each watershed was examined using the interim guidance and a matrix of findings was developed to prioritize COCs as high, medium, or low. The intent of the identification of frequency of occurrence is to provide a tool to watershed groups for prioritizing water quality concerns and identifying activities and actions. Water quality priority ratings are also presented based on the methodology presented in the Baseline Long-Term Effectiveness Assessment (BLTEA) report (WESTON, MOE, & LWA 2005). Constituent groups and stressor groups were given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicated that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on the data from the BLTEA report and included current results presented in this 2004-2005 annual report. Statistical Methods Relationships between toxicity and COC were examined by MLS to determine which COC may have an effect on toxicity. Additionally, long-term trends in the data for Agua Hedionda Creek, Tecolote Creek, and Chollas Creek were examined by regression analysis to determine whether an observed upward or downward tendency of the data was statistically significant. ES.3 Cross Watershed Comparison Statistical Methods A cross-watershed comparison was performed to assess all information from each watershed together in order to evaluate and rank watersheds across the region. Statistical tools used for the cross watershed comparison include scatterplot analysis, regression analysis, analysis of variance (ANOVA), and multivariate cluster analysis. The relationship between toxicity and constituents of concern for the cross watershed analysis was evaluated by two methods. The first method uses a multiple regression model to correlate changes in toxicity to changes in COC levels in the water. The second method, a threshold analysis, was used to clarify relationships following the regression analyses using the COC that were significant components of the final multiple regressions. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-4 ES.4 Urban Runoff Monitoring Results Results of the monitoring and assessment conducted for the 2004-2005 program are presented on a watershed basis, which meets the requirements set forth in Order 2001-01. It is important to note that value can also be derived through examination of region-wide trends and relationships presented in Section 13, Regional Assessments, in this report. ES.4.1 Santa Margarita River WMA The Santa Margarita River watershed is the second largest in the San Diego hydrologic region. The primary land use within the contributing runoff area is undeveloped (64%). The Santa Margarita River watershed management area has one mass loading station established in 2001 to characterize storm water runoff within the watershed. Sample collection is coordinated by the US Navy in Camp Pendleton for security reasons. Storm Water Monitoring The Navy did not collect samples during 2004-2005 at the Santa Margarita River location due to equipment loss in excessive flooding during the first storm event of the 2004-2005 monitoring season. The Navy indicated they would not sample the remainder of the 2004-2005 monitoring season. Stream Bioassessment Stream bioassessment monitoring in the Santa Margarita River WMA included two lower watershed urban affected sites in Santa Margarita River proper, as well as two reference sites in the upper tributaries. All of the sites had mostly undisturbed conditions, and the Index of Biotic Integrity (IBI) quality ratings ranged from Poor to Good in the 2004-2005 surveys. As in previous surveys, the Santa Margarita River monitoring sites were among the highest rated of the urban affected sites in San Diego County, although the IBI scores in May 2005 were lower than usual. Biological metric values and water quality measures indicated that this watershed is one of the least impacted in San Diego County. Ambient Bay and Lagoon Monitoring Sediments in Santa Margarita River Estuary and Oceanside Harbor were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found. These sites were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that six metals, including arsenic, chromium, copper, lead, nickel, and zinc, were found in Santa Margarita River Estuary sediments. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. No metal exceeded its respective ERL in Santa Margarita River Estuary, the mean ERM-Q for Santa Margarita River Estuary was the lowest of any of the 12 embayments assessed in the ABLM Program and was well below the threshold of 0.10. Sediments with mean ERM-Q values below this threshold have a low probability of producing adverse biological EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-5 effects (Long et al. 1998). There were no PAHs, PCBs, or pesticides found above the detection limit in the Santa Margarita River Estuary. In Oceanside Harbor, seven metals, including arsenic, chromium, copper, lead, nickel, selenium and zinc, were detected in the sediments. Two metals (copper and zinc) exceeded the ERL in Oceanside Harbor. The mean ERM-Q for Oceanside Harbor was above 0.10. There were no PAHs, PCBs, or pesticides found above the detection limit in Oceanside Harbor. Sediment toxicity was not significantly different from that of the control sample at both locations. Benthic community indices suggested that biotic community in the Estuary sediments were similar to other embayments in the County and was dominated by a gammarid amphipod and polychaete worms. For the Santa Margarita River Estuary the relative ranks were one for chemistry, two for toxicity, and five for benthic community structure. The relative ranks for Oceanside Harbor were ten for chemistry, six for toxicity, and two for benthic community. The relative quality for both Santa Margarita River Estuary and Oceanside Harbor increased from the 2003 ABLM monitoring year. WMA Assessment The ability to apply the triad decision matrix was limited due to the lack of data from the Santa Margarita River MLS during the 2004-2005 monitoring season. For the Santa Margarita River WMA, turbidity and fecal coliform were identified as high frequency of occurrence COC, TSS was identified as a medium frequency of occurrence COC, and TDS and nitrate were identified as low frequency of occurrence COC. There was no evidence of persistent toxicity and no indications of benthic alteration found in the Santa Margarita River. Based on the triad matrix, there was evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and no indications of benthic alteration. The WMA assessment findings agreed with the BLTEA rating priorities for the Santa Margarita River WMA, which found sediments to be a high priority (A rating) constituent. The BLTEA ratings indicated a B rating for nutrients, bacteria, gross pollutants and benthic alteration. ES.4.2 San Luis Rey River Watershed Management Area The San Luis Rey River watershed is the third largest watershed in San Diego County. The contributing runoff area is representative of the entire watershed which is approximately 29% open space and 25% agricultural. Storm Water Monitoring Summary Total dissolved solids continue to be the primary water quality concern in the watershed for wet weather events. Concentrations of other constituents, including BOD, pH, Diazinon, and fecal coliform have exceeded WQO occasionally. There is an increasing trend in indicator bacteria concentrations. The San Luis Rey River has not been identified as a TIE candidate site based upon the Triad Decision Matrix. Stream Bioassessment The San Luis Rey River WMA was sampled at three sites, two urban affected sites in the San Luis Rey River, and one reference site in Doane Creek, a small tributary on Mt. Palomar. The San Luis Rey River sites had Index of Biotic Ratings of Very Poor for both sites and both surveys. The in-stream physical habitat of these sites was marginal, which could limit macroinvertebrate colonization. The high specific conductivity readings in October 2004, and the high silt deposits in May 2005 at Benet Road indicate that water quality may also have been a factor. The reference site in Doane Creek, while not ecologically EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-6 representative of the other sites in the program, provided interesting and valuable data for the region and was rated Very Good during both surveys. Ambient Bay and Lagoon Monitoring Program Sediments in San Luis Rey River Estuary were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COCs were most likely to be found. These sites were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that six metals, including arsenic, chromium, copper, lead, nickel, and zinc, were found in the Estuary sediments. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. Concentrations of metals were low and only one (nickel) exceeded the ERL value. The mean ERM quotient was 0.122. This value exceeded the ERM-Q threshold of 0.10. There were no PAHs, PCBs, or pesticides found above the detection limit in San Luis Rey River Estuary. Sediment toxicity was not significantly different from that of the control sample. Benthic community indices suggested that the biotic community in the Estuary ranked low compared to other embayments in San Diego County. For San Luis Rey River Estuary, the relative ranks were five for chemistry, four for toxicity, and eight for benthic community structure. Based on the 2004 ABLM monitoring program, the relative quality of San Luis Rey River Estuary decreased compared to the 2003 rankings. WMA Assessment For the San Luis Rey River WMA, TDS was the only high frequency of occurrence COC followed by turbidity, nitrate, ammonia, and all three bacterial indicators which were all low frequency of occurrence COC. There was no evidence of persistent toxicity in San Luis Rey River, however, the benthic community appeared to be limited by unknown factors. While elevated TDS levels may be affecting diversity, there may be other constituents not measured that are impacting the benthic invertebrate community. Only total dissolved solids was identified as having a high frequency of occurrence. However, TDS is not considered in the triad decision making process since the water quality objectives for this parameter as defined in the Basin Plan are established for municipal drinking water and do not necessarily reflect impacts on the ecology of the watersheds. Therefore, based on the triad decision matrix, there was no evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and indications of benthic alteration. In addition to the WMA assessment findings, the LTEA findings suggest that sediments and bacteria are also high priority (A rated) constituents followed by benthic alteration which was given a B rating. All other constituents were given either a C or D rating. ES.4.3 Carlsbad Watershed Management Area The Carlsbad watershed is the third most densely populated watershed in the San Diego region. This program monitors mass loading stations in the Agua Hedionda and Escondido Creek sub-watershed areas. For the Agua Hedionda sub-watershed which accounts for 11% of the Carlsbad watershed, land EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-7 use within the contributing runoff area is primarily residential (33%), undeveloped (25%), and agriculture (11%). For the Escondido Creek sub-watershed which accounts for approximately 33% of the Carlsbad watershed, land use within the contributing runoff area is predominantly undeveloped (35%), residential (25%), and parks (16%). Storm Water Monitoring Summary Both the Escondido Creek sub-watershed and the Agua Hedionda sub-watershed have similar water quality concerns. Bacteria, total dissolved solids, total suspended solids, and turbidity have consistently exceeded water quality objectives. Last year, the watersheds also had exceedances of BOD and COD. In Agua Hedionda Creek, increasing trends were observed for fecal coliform, TSS, turbidity, COD, TKN, total and dissolved phosphorus and total lead. Since no toxicity at Agua Hedionda Creek was observed in Ceriodaphnia toxicity tests during the 2004- 2005 storm season, TIE testing was not performed. The absence of toxicity in the Escondido Creek storm water samples excluded the need for TIE testing. Stream Bioassessment The Carlsbad WMA included four bioassessment monitoring sites, two on Agua Hedionda Creek and two on Escondido Creek. Index of Biotic Integrity scores rated the benthic communities Very Poor at all four sites during both surveys, with the exception of Escondido Creek in Elfin Forest, which was rated Poor in the October 2004 survey. A substantial amount of sedimentation occurred due to the heavy winter rains between the October and May surveys in Escondido Creek. The Aqua Hedionda Creek sites both had marginal in-stream habitat conditions, which may have limited macroinvertebrate colonization. Ambient Bay and Lagoon Monitoring Program There are four coastal embayments in the Carlsbad WMA that were monitored in the ABLM Program: Buena Vista Lagoon, Agua Hedionda Lagoon, Batiquitos Lagoon, and San Elijo Lagoon. Buena Vista Lagoon is unique in comparison to all other embayments assessed in the ABLM Program. Because this Lagoon is closed to the ocean, it receives no tidal exchange, has no salt water influence, and functions more as a freshwater lake or wetland than a coastal estuary. In Phase I, a stratified random approach was used at all four sites to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size). Sites in the Buena Vista Lagoon were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven of the nine metals analyzed were found above the reporting limit, including arsenic, cadmium, chromium, copper, lead, nickel, and zinc. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. Concentrations of all the metals were below their respective ERLs except for copper and zinc. The mean ERM quotient was 0.204. This value exceeded the threshold of 0.10. The mean ERM-Q for Buena Vista Lagoon was the third highest among the embayments assessed in the ABLM Program. There were no PAHs, PCBs, or pesticides found above the detection limit in Buena Vista Lagoon. Sediment toxicity to E. estuarius was not significantly different from that of the control sample. Buena Vista Lagoon had the lowest abundance and number of species than any other embayment assessed. The low rankings are likely due to the influence of fresh water and lack of tidal flushing in the Lagoon rather than a greater than average contaminant loading. For Buena Vista Lagoon, the relative ranks were nine for chemistry, one for EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-8 toxicity, and nine for benthic community structure. The relative quality of Buena Vista Lagoon increased compared with the 2003 ranking. Sediments in Agua Hedionda Lagoon were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that six metals (arsenic, chromium, copper, lead, nickel, and zinc) were found in Agua Hedionda Lagoon at concentrations above the detection limit. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. Concentrations were slightly higher than those found in other embayments, but only arsenic exceeded the respective ERL. The mean ERM-Q for Agua Hedionda Lagoon was 0.122 which just exceeds the threshold value of 0.10. The mean ERM-Q for Agua Hedionda Lagoon was the fifth highest among the embayments assessed in the ABLM Program. There were no PAHs, PCBs, or pesticides found above the detection limit in Agua Hedionda Lagoon. Percent survival of E. estuarius exposed to Agua Hedionda Lagoon sediments was 85%, which was not significantly different from that of the control. Benthic community indices suggested that the biotic community in the Lagoon sediments was intermediate compared to other embayments in San Diego County. The infaunal community was dominated by the sea slug Acteocina inculta, which accounted for 37.2 % of the taxa collected. For Agua Hedionda Lagoon, the relative ranks were five for chemistry, seven for toxicity, and six for benthic community structure. Agua Hedionda Lagoon experienced an increase in relative quality compared with last year’s ranking. Sediments in Batiquitos Lagoon were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that six metals were found in Batiquitos Lagoon, including arsenic, chromium, copper, lead, nickel, and zinc. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. Concentrations of metals were low and only arsenic exceeded the ERL. The mean ERM-Q for Batiquitos Lagoon based on these constituents was 0.124, which exceeded the threshold of 0.10. There were no PAHs, PCBs, or pesticides found above the detection limit in Batiquitos Lagoon. The percent survival of test organisms exposed to sediments from Batiquitos Lagoon was 67% and was significantly different than that of the control, suggesting the presence of toxic elements in the Lagoon. However, analyses of benthic community indices suggested that the biotic community in Batiquitos Lagoon ranked high compared to the other embayments. Three taxa dominated the infaunal community in Batiquitos Lagoon: the barley snail, Barleeia sp, the herbivorous amphipod, Ampithoe longimana, and the sea slug, Acteocina inculta. For Batiquitos Lagoon, the relative ranks were 6 for chemistry, 10 for toxicity, and 2 for benthic community structure. The relative quality in Batiquitos Lagoon increased in 2004 compared with the 2003 ranking. Sediments in San Elijo Lagoon were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven of the nine metals assessed were found in the Lagoon sediments, including arsenic, cadmium, chromium, copper, lead, nickel, and zinc. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. None of the metals detected exceeded its respective ERL value. The mean ERM-Q for San Elijo Lagoon was 0.076, which did not exceed the threshold value of 0.10 and therefore does not suggest the potential for increased toxicity. There were no PAHs, PCBs, or pesticides found above the detection limit in San Elijo Lagoon. Percent survival of E. estuarius exposed to San Elijo Lagoon sediments was 88%, but was not statistically different from that of the control. Benthic community indices suggested that the biotic community in the Lagoon sediments EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-9 ranked low compared to other embayments in San Diego County. This was primarily due to the lack of organisms found at Site 3L-2, which is located in the inner-most part of the Lagoon and receives minimal tidal flushing. The infaunal community was dominated by polychaete worms and amphipods. For San Elijo Lagoon, the relative ranks were two for chemistry, five for toxicity, and seven for benthic community structure. The relative quality in San Elijo Lagoon increased compared with the 2003 ABLM ranking. Third Party Data Third party data was collected from 10 locations in 2002 within the Carlsbad watershed under the Surface Water Ambient Monitoring Program (SWAMP) and was provided by the San Diego Regional Water Quality Control Board. Sampling sites were located on Loma Alta Creek, Buena Vista Creek, Buena Creek, Agua Hedionda Creek, San Marcos Creek, Encinitas Creek, Cottonwood Creek, and Escondido Creek. Data collected from Agua Hedionda Creek and Escondido Creek were compared to the mass loading station and dry weather data results to provide qualitative assessments with current wet and dry weather results. The remaining stations within the watershed were too spatially disconnected from the MLS to correlate the data with any of the wet and dry weather monitoring results, however, exceedances were noted. The station located on Agua Hedionda Creek upstream of the MLS had consistent water quality objective exceedances for sulfate, manganese and toxicity. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedances were for toxicity to Ceriodaphnia and Hyalella. Two sampling locations were located on Escondido Creek: one station was located upstream of the MLS while the second location was located in the same vicinity as the MLS. There were water quality objective exceedances for pH, sulfate, manganese, Diazinon, and toxicity at both stations. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedances were for Diazinon and Ceriodaphnia survival and reproduction. Exceedances observed at the other seven stations within the Carlsbad watershed were similar to exceedances in Agua Hedionda Creek and Escondido Creek. Sulfate, manganese, and toxicity consistently exceeded objectives at all sites. Other parameters, including pH, nitrate and nitrite as N, and Diazinon exceeded objectives sporadically. WMA Assessment For Agua Hedionda Creek, TSS, turbidity, fecal coliform, and enterococcus were identified as high frequency of occurrence COC, TDS and diazinon were identified as medium frequency of occurrence COC, and pH, COD, ammonia, and total coliform were identified as low frequency of occurrence COC. For Escondido Creek, TDS, turbidity, total coliform, and fecal coliform were identified as high frequency of occurrence COC, enterococcus was identified as a medium frequency of occurrence COC, and TSS and nitrate were identified as low frequency of occurrence COC. Based on the triad matrix for Agua Hedionda and Escondido Creeks, there was evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and indications of benthic alteration. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-10 The WMA assessment findings agreed with the BLTEA rating priorities, which found sediments and bacteria to be high priority (A rating) constituents followed by nutrients and benthic alteration which were given a B rating. ES.4.4 San Dieguito River Watershed Management Area The San Dieguito River MLS run-off area accounts for only 8% of the overall San Dieguito WMA. Approximately 86% of the watershed lies behind dams (Coastal Conservancy 2001). The major land uses within the contributing runoff area are undeveloped (24%), parks (24%), residential (21%), and agricultural (18%). Storm Water Monitoring Summary Elevated levels of TDS during wet weather continues to be the primary water quality concern in the watershed. Concentrations of other constituents, particularly fecal coliform bacteria, exceeded WQO occasionally. There were three dry weather monitoring sites located upstream of the mass loading station, but the data suggested that there was no clear link between dry and wet weather constituents. This mass loading station has not been identified as a TIE candidate site based upon the Triad Decision Matrix. Stream Bioassessment The San Dieguito River WMA was sampled at two sites, Green Valley Creek at West Bernardo Drive, and San Dieguito River below Lake Hodges in October 2004 and May 2005. The macroinvertebrate community of Green Valley Creek had an Index of Biotic Integrity rating of Poor and Very Poor for the October and May surveys, respectively. San Dieguito River was rated Very Poor in October and Poor in May. At the San Dieguito River site, nine individuals of the sensitive caddisfly, Oxyethira, were collected. Ambient Bay and Lagoon Monitoring Sediments in San Dieguito Lagoon were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COCs were most likely to be found (i.e., those with the highest TOC and smallest grains size). These sites were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven metals (arsenic, cadmium, chromium, copper, lead, nickel, and zinc), which were common to all the embayments assessed, were found in the Lagoon sediments. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. Only cadmium exceeded the ERL value. The mean ERM-Q for San Dieguito Lagoon was 0.088 which is below the threshold of 0.10 and suggests a low probability of producing adverse biological effects (Long et al. 1998). There were no PAHs, PCBs, or pesticides found above the detection limit in San Dieguito Lagoon. However, percent survival of test organisms exposed to San Dieguito Lagoon sediments was 66%, which is significantly different from that of the control, indicating that the sediments were toxic to the test organisms. The polychaete, Capitella capitata, dominated the benthic community in the Lagoon, accounting for 42.5 % of all the animals collected. For San Dieguito Lagoon, the relative ranks were 3 for chemistry, 10 for toxicity, and 4 for benthic community structure. The relative quality decreased in 2004 compared with the 2003 ranking. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-11 WMA Assessment For the San Dieguito River, only TDS was identified as a high frequency of occurrence COC, fecal coliform was identified as a medium frequency of occurrence COC, and turbidity, total coliform, and enterococcus were identified as low frequency of occurrence COC. The in-stream benthic community appears to be limited by unknown factors, and while elevated TDS levels may be affecting diversity, there may be other constituents not measured that are impacting the benthic community. Only total dissolved solids was identified as having a high frequency of occurrence. However, TDS is not considered in the triad decision making process since the water quality objectives for this parameter as defined in the Basin Plan are established for municipal drinking water and do not necessarily reflect impacts on the ecology of the watersheds. Therefore, based on the triad decision matrix, there was no evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and indications of benthic alteration. In addition to the WMA assessment findings, the BLTEA ratings found sediments as a high priority (A) rating followed by gross pollutants, bacteria, benthic alteration, and toxicity which were given a B rating. ES.4.5 Los Peñasquitos Creek Watershed Management Area The Los Peñasquitos Creek run-off area accounts for approximately 60% of the Los Peñasquitos watershed management area. The major land uses within the contributing runoff area are parks (29%), residential (28%), and undeveloped (24%). Storm Water Monitoring Summary Elevated levels of TDS during wet weather continues to be the primary water quality concern in the watershed. Elevated levels of other constituents, particularly fecal coliform bacteria, occur occasionally. There is a significant decreasing trend in Diazinon concentrations. There has been no toxicity associated with storm water in any of the 12 storms assessed since 2001. The only COC that was common between wet and dry weather monitoring was turbidity. This mass loading station has not been identified as a TIE candidate site based upon the Triad Decision Matrix. Stream Bioassessment The Los Peñasquitos WMA was sampled at two sites. The upstream site was in Los Peñasquitos Creek in Poway, and the downstream site was in Carroll Canyon Creek in Sorrento Valley. Both of the sites had Index of Biotic Integrity ratings of Very Poor or Poor categories. The Carroll Canyon Creek site was rated slightly higher than the upstream site on Los Peñasquitos Creek, possibly due to different watershed areas contributing to the different streams. Ambient Bay and Lagoon Monitoring Sediments in Los Peñasquitos Lagoon were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COCs were most likely to be found (i.e., those with the highest TOC and smallest grains size). These sites were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-12 The results of the chemistry assessment indicated that seven of the nine metals assessed were found in the Lagoon sediments, including arsenic, chromium, copper, lead, nickel, selenium, and zinc. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. Only arsenic exceeded the ERL value. The mean ERM-Q for Los Peñasquitos Lagoon was 0.111, which was slightly above the threshold value of 0.10 and suggests a small potential for increased toxicity. There were no PAHs, PCBs, or pesticides found above the detection limit in Los Peñasquitos Lagoon during the 2004 program. Percent survival of test organisms exposed to Los Peñasquitos Lagoon sediments was 96% and was not statistically different than that of the control. Benthic community indices suggested that the biotic community in the Lagoon sediments was intermediate in comparison to other embayments in San Diego County. The infaunal community was dominated by the crustacean, Grandidierella japonica and Phoronids. For Los Peñasquitos Lagoon, the relative ranks were four for chemistry, three for toxicity, and six for benthic community structure. The relative quality of the Lagoon increased in 2004 compared with last year’s ranking. Third Party Data Third party data was collected from three locations in 2002 within Los Peñasquitos watershed under the Surface Water Ambient Monitoring Program (SWAMP) and was provided by the San Diego Regional Water Quality Control Board. Sampling sites were located on Los Peñasquitos Creek, Soledad Canyon Creek, and Poway Creek. Data collected from Los Peñasquitos Creek were compared to the mass loading station and dry weather data results to provide qualitative assessments with current wet and dry weather results. The other two stations within the watershed were too spatially disconnected from the MLS to correlate the data with any of the wet and dry weather monitoring results, however, exceedances were noted. The station located on Los Peñasquitos Creek in the same vicinity as the mass loading station had water quality objective exceedances for turbidity, pH, sulfate, Diazinon, methyl parathion, and toxicity. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedances were for turbidity during wet and dry weather and Diazinon during wet weather, however these exceedances were not persistent. Exceedances observed at the other two stations within Los Peñasquitos watershed were similar to exceedances that were found in Los Peñasquitos Creek. Sulfate, manganese and toxicity consistently exceeded objectives at all sites. WMA Assessment For the Los Peñasquitos Creek WMA, only TDS was identified as a high frequency of occurrence COC, fecal coliform was identified as a medium frequency of occurrence COC, and turbidity, ammonia, orthophosphate, total coliform, and enterococcus were identified as low frequency of occurrence COC. Third party data collected in 2002 under SWAMP indicated that sulfate, manganese, and toxicity had exceedances of the water quality objective throughout Los Peñasquitos watershed. The in-stream benthic community appears to be limited by unknown factors, and while high TDS levels may be enough of a stress to insects, other constituents not monitored in the Los Peñasquitos Creek MLS watershed may also be affecting the benthic invertebrate community. Only total dissolved solids was identified as having a high frequency of occurrence. However, TDS is not considered in the triad decision making process since the water quality objectives for this parameter as EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-13 defined in the Basin Plan are established for municipal drinking water and do not necessarily reflect impacts on the ecology of the watersheds. Therefore, based on the triad decision matrix, there was no evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and indications of benthic alteration. In addition to the WMA assessment findings, the BLTEA ratings found sediments and bacteria to be the highest priority (A rated) constituents for the Los Peñasquitos WMA followed by benthic alteration which was given a B rating. ES.4.6 Mission Bay Watershed Management Area The Mission Bay watershed management area includes three hydrologic areas: Scripps, Miramar, and Tecolote. This program monitors a mass loading station only in the Tecolote Creek sub-watershed. For the Tecolote Creek sub-watershed, which accounts for approximately 14% of the Mission Bay watershed management area, the primary land uses within the contributing runoff area are residential (43%) and transportation (21%). Storm Water Monitoring Summary Four parameters appear to frequently exceed the water quality objectives in storm water runoff at the Tecolote Creek MLS: fecal coliform bacteria, TSS, turbidity, and Diazinon. Concentrations of MBAS, BOD, ammonia as N, Diazinon, and two metals (total cadmium and total lead) have shown statistically significant decreasing trends, while increasing trends have been observed for total phosphorus and enterococcus. The constituents that had exceedances during both dry and wet weather monitoring in 2004-2005 include total phosphorus and turbidity. There has been toxicity associated with storm water, but it appears to be related to specific storm events rather than a persistent pattern. This mass loading station has not been identified as a TIE candidate site based upon the Triad Decision Matrix. Stream Bioassessment The Mission Bay WMA was sampled at two sites. One site was in Rose Creek, downstream of Highway 52, and the other site was in Tecolote Creek in Tecolote Canyon Natural Park. The macroinvertebrate community of both sites had Index of Biotic Integrity ratings of Poor in October and Very Poor in May, with substantial seasonal variation in the total IBI scores. Seasonal community dynamics showed similar patterns at both sites, with percent collector filterers plus collector gatherers (represented at both sites by Simulium, Chironomids, and Ostracods) and macroinvertebrate density much higher in May, and with percent predators, taxa richness, and overall IBI score higher in October. Ambient Bay and Lagoon Monitoring Sediments in Mission Bay were monitored as part of the 2003 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COCs were most likely to be found (i.e., those with the highest TOC and smallest grains size). These sites were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven of the nine metals assessed were found in Mission Bay sediments, including arsenic, chromium, copper, lead, nickel, selenium, and zinc. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-14 comparison purposes only and are not water or sediment quality objectives. Of the metals detected, arsenic, copper, lead, and zinc exceeded their respective ERL values, but all concentrations were well below their respective ERMs. There were no PAHs, PCBs, or pesticides found above the detection limit in Mission Bay during the 2004 program. The mean ERM-Q for Mission Bay was the highest of any embayment assessed in the ABLM Program (0.299). In contrast to the sediment chemistry results, the percent survival of test organisms exposed to Mission Bay sediments was not significantly different from that of the control, suggesting that the sediments were not significantly toxic to the test organisms. Benthic community indices suggested that the biotic community in Mission Bay had the lowest combined index score of all the embayments assessed in the ABLM Program. The infaunal community was dominated by the barley snail, Barleeia sp., and the polychaetes, Exogone lourei, and Aphelochaeta sp. For Mission Bay, the relative ranks were 11 for chemistry, 8 for toxicity, and 1 for benthic community structure. Mission Bay experienced a decrease in relative quality compared with last year’s ranking. Third Party Data Third party data was collected from two locations in 2002 within the Mission Bay watershed under the Surface Water Ambient Monitoring Program (SWAMP) and was provided by the San Diego Regional Water Quality Control Board. The sampling sites were located on Tecolote Creek near the mass loading station and on Rose Canyon Creek. Data collected from Tecolote Creek were compared to the mass loading station and dry weather data results to provide qualitative assessments with current wet and dry weather results. The Rose Canyon Creek station was too spatially disconnected from the MLS to correlate the data with any of the wet and dry weather monitoring results, however, exceedances were noted. There were consistent water quality objective exceedances for sulfate, manganese, and toxicity at the Tecolote Creek station. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedance was for toxicity during wet weather. Exceedances observed at Rose Canyon Creek included sulfate, manganese, turbidity, pH, Diazinon, and toxicity. WMA Assessment For the Mission Bay WMA, turbidity, and all three bacterial indicators were identified as high frequency of occurrence COC, TSS and Diazinon were identified as medium frequency of occurrence COC, and ph, COD, and orthophosphate were identified as low frequency of occurrence COC. Third party data collected in 2002 under SWAMP indicated that sulfate, manganese, and toxicity had exceedances of water quality objectives at the Tecolote Creek monitoring station. There was no evidence of persistent toxicity associated with samples collected from the Tecolote Creek MLS. However, the in-stream benthic community was ranked as poor and very poor, suggesting evidence of benthic alteration. Physical habitat disturbance may play a role in the limited benthic community. Insecticides such as Diazinon, which had a medium frequency of occurrence in the watershed, may also be a limiting factor. Synergistic effects and unknown contaminants in the Mission Bay watershed may also be harming the benthic invertebrate community but more study is needed. Based on the triad decision matrix, there was evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and indications of benthic alteration. In addition to the WMA assessment findings, the BLTEA ratings found heavy metals and bacteria were the highest priority (A rated) constituents for the Mission Bay WMA followed by sediments, nutrients, and bacteria which were given B ratings. The heavy metals priority rating found in the BLTEA rating was EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-15 primarily due to the 303(d) listings for metals in the Miramar and Tecolote sub-watersheds even though the WMA assessment did not indicate metals were an overall priority. ES.4.7 San Diego River Watershed Management Area The San Diego River watershed is the second largest watershed in San Diego County. The contributing runoff area to the MLS is approximately 39% of the San Diego watershed land area. The major land uses within the contributing runoff area are residential (29%), parks (24%), and undeveloped (21%). Storm Water Monitoring Summary Turbidity and bacterial indicators appear to be the most consistent, primary water quality concerns within the watershed. A significant downward trend in Diazinon concentrations has been observed. The exceedances that were common between the wet and dry weather monitoring program were fecal coliform and turbidity. This mass loading station has not been identified as a TIE candidate site based upon the Triad Decision Matrix. Stream Bioassessment The San Diego River WMA was sampled at two monitoring sites on San Diego River, one in Mission Trails Regional Park, and one near Morena Blvd. in Mission Valley. The Mission Trails site had an Index of Biotic Integrity rating of Poor in October and Very Poor in May, and the Mission Valley site had an IBI rating of Very Poor for both surveys. The Mission Valley site was one of the lowest rated sites in the San Diego County Storm water program for both the October and May surveys, but increased substantially from the previous years surveys. Ambient Bay and Lagoon Monitoring No sampling was performed at the mouth of the San Diego River as part of the Ambient Bay and Lagoon Monitoring program. Third Party Data Third party data was provided by Padre Dam Municipal Water District (Padre Dam). Monthly monitoring results collected from January 2004 through December 2004 at six locations upstream from the MLS were evaluated and compared to wet weather and dry weather sample results. Parameter groups that were included in the Padre Dam data include nutrients, conventionals, and microbiology. The sample results from Padre Dam represent a snapshot of the water quality conditions upstream of the MLS throughout the year. For parameters on the 303(d) list for the lower San Diego River, results from Padre Dam exceeded the Basin Plan WQO for TDS in 52 of 72 samples; turbidity exceeded the WQO in 8 of 72 samples; dissolved oxygen exceeded the WQO in 33 of 72 samples, fecal coliform exceeded the WQO in 17 of 72 samples, and E.coli exceeded the WQO in 20 out of 72 samples. Parameters that exceeded water quality objectives in Padre Dam data, dry weather data, and wet weather MLS data include TDS, turbidity, fecal coliform, and total coliform. WMA Assessment For the San Diego River WMA, turbidity and all three bacterial indicators were identified as high frequency of occurrence COC followed by TDS, which was identified as a medium frequency of occurrence COC. TDS during wet weather monitoring and monthly monitoring within the watershed by Padre Dam showed a medium frequency of occurrence but appears to be related to groundwater EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-16 influences and local conditions. As noted in Section 10.2.3, the TDS water quality objective may not accurately reflect the natural conditions of the San Diego River WMA. Dissolved oxygen in samples collected by Padre Dam exceeded the Basin Plan water quality objective 46% of the time. Although ammonia and orthophosphate in dry weather data may indicate localized issues within the WMA, the evaluation and combination of Padre Dam data in the assessment process suggests that on a regional scale these constituents do not frequently exceed water quality objectives. The occurrence of these constituents may be a result of numerous activities or sources. The stream habitat quality was rated Poor in Mission Trails, a large open recreation space, and Very Poor in Mission Valley, a highly urbanized residential and commercial corridor. The Very Poor rating in Mission Valley may be a result of physical disturbances to habitat, insecticides or other COC that are not analyzed for in this program, or algal growth observed and measured as chlorophyll within the stream. Based on the triad decision matrix, there was evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and indications of benthic alteration. In addition to the WMA assessment findings, the BLTEA ratings found sediments, bacteria, and benthic alteration were the highest priority (A rated) constituents for the San Diego River WMA followed by pesticides which was given a B rating. ES.4.8 San Diego Bay Watershed Management Area The San Diego Bay watershed management area consists of three major watersheds, including the Pueblo San Diego watershed, the Sweetwater watershed, and the Otay watershed. The Chollas sub-watershed within the Pueblo San Diego watershed and the Sweetwater watershed are currently monitored in this program. The Otay watershed has not been sampled during this monitoring program since the majority of runoff is captured in the Otay reservoir and is prevented from flowing downstream. The differences in water quality between the Pueblo San Diego and Sweetwater watersheds likely reflect the differences in land uses. The Chollas sub-watershed within the Pueblo San Diego watershed drains a very densely populated, urban area. Nearly 65% of the drainage area is residential and another 17% is commercial. The Sweetwater watershed drainage area consists of 50% vacant or undeveloped land, 30% residential and only 10% commercial. Storm Water Monitoring Summary Water quality concerns within Chollas Creek are typical of heavily residential and commercial areas with frequent water quality exceedances of turbidity, TSS, bacterial indicators, total and dissolved copper, and total zinc. Turbidity, fecal coliform, ammonia, and copper (total during wet weather and dissolved during dry weather) were the only constituents that exceeded during wet weather monitoring and the 2004 dry weather monitoring efforts. Sweetwater watershed has nearly 50% open space and a lower percentage of residential (30%) and commercial (10%) than Chollas Creek. Aside from bacterial indicators, TDS, and turbidity, Sweetwater River does not have other persistent exceedances of water quality objectives. Fecal coliform was the only constituent identified as a high frequency COC during wet weather and only total and fecal coliform concentrations exceeded objectives during the 2004 dry weather monitoring efforts. Chollas Creek and Sweetwater River were identified as potential TIE candidate sites based on toxicity to Hyalella and Selenastrum, respectively. Since the toxicity was not consistent among events and was relatively slight, a standard TIE would not likely determine the cause. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-17 Stream Bioassessment Three monitoring sites were sampled in the San Diego Bay WMA. One site was in Chollas Creek at Federal Blvd., and two sites were in Sweetwater River, at Highway 94 in Rancho San Diego and along Bonita Road. Chollas Creek had Index of Biotic Integrity ratings of Poor and Very Poor, and the Sweetwater River sites were rated Very Poor for both sites and for both surveys. The Sweetwater River sites had in-stream physical characteristics that provided little stable habitat for macroinvertebrate colonization, which may have negatively affected the IBI scores. Ambient Bay and Lagoon Monitoring Program Sediments in the Sweetwater River Estuary were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COCs were most likely to be found (i.e., those with the highest TOC and smallest grains size). These sites were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that six of the nine metals assessed were found in Sweetwater River sediments, including arsenic, chromium, copper, lead, nickel, and zinc. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. None of the metals detected exceeded their respective ERL or ERM values. The mean ERM-Q for Sweetwater River Estuary was 0.140, the fourth highest of any embayment assessed in the ABLM Program. There were no PAHs, PCBs, or pesticides found above the detection limit in Sweetwater River Estuary during the 2004 program. Percent survival of E. estuarius exposed to Sweetwater River Estuary sediments was 79% and was not different from that of the control. The benthic community structure had a low combined index score. The infaunal community was dominated by a genus of barley snail, polychaete worms, and mussels. For Sweetwater River Estuary, the relative ranks were eight for chemistry, nine for toxicity, and three for benthic community structure. The relative quality in Sweetwater River Estuary increased in 2004 compared with the 2003 ranking. No sampling was performed at the mouth of Chollas Creek as part of the Ambient Bay and Lagoon Monitoring program. WMA Assessment The Chollas sub-watershed within the Pueblo San Diego watershed drains a very densely populated, urban area. Nearly 65% of the drainage area is residential and another 17% is commercial. Turbidity, all three indicator bacteria, Diazinon, total and dissolved copper, and total zinc were identified as high frequency of occurrence COC. Medium frequency of occurrence COC were identified for COD and TSS, followed by BOD, MBAS, ammonia, orthophosphate, and total lead which were identified as low frequency of occurrence COC. Based on the triad decision matrix for Chollas Creek, there was evidence of persistent water quality objective exceedances, there was evidence of persistent toxicity, and evidence of benthic alteration. The benthic community impacts and stream habitat impairments may be a result of elevated COC or physical alterations to the riparian corridor. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-18 The Sweetwater watershed drainage area consists of 50% vacant or undeveloped land, 30% residential, and only 10% commercial. The contrast in land use compared to Chollas Creek may likely be the reason for better observed (based on data assessed) water quality in Sweetwater River. Only fecal coliform was identified as a high frequency of occurrence COC within Sweetwater River. TDS was identified as a medium frequency of occurrence COC, followed by turbidity, total coliform, enterococcus, and Diazinon, which were identified as low frequency of occurrence COC. The bioassessment monitoring identified Sweetwater River as having a Very Poor IBI score and was the lowest rated site in the county in the October Survey. Based on the triad decision matrix for Sweetwater River, there was no evidence of persistent water quality objective exceedances, there was evidence of persistent toxicity, and evidence of benthic alteration. The BLTEA ratings for the overall San Diego Bay WMA found that sediment was rated as the highest priority constituent (A) followed by pesticides, bacteria, and benthic alterations which were given B ratings. All other constituents were given either a C or D rating. The BLTEA findings are similar to the WMA assessments for both Chollas Creek and Sweetwater River. Turbidity, bacteria, and Diazinon had a high frequency of occurrence in Chollas Creek, while bacteria had a high frequency of occurrence in Sweetwater River. There was evidence of benthic alteration in both sub-watersheds. ES.4.9 Tijuana River Watershed Management Area The Tijuana River watershed management area is the largest of the San Diego watersheds covering over 1.1 million acres. Mexico governs the majority of the Tijuana River watershed (73%) with the remaining areas belonging to the United States. Undeveloped areas account for 58% of U.S. lands, with another 25% devoted to parks. The River flows through Tijuana, Mexico and runoff contributions come from both Mexico and the United States. Storm Water Monitoring Summary Constituents most prevalent in Tijuana River that pose the greatest concern are typical of conditions found with untreated wastewater. All three bacterial indicators, BOD, COD, TSS, turbidity, and nutrients (un-ionized ammonia as N and total phosphorus) consistently exceeded water quality objectives. In addition, pesticides are also prevalent in elevated concentrations. Diazinon, in particular, has exceeded water quality objectives in 11 of the last 12 storms and has been identified as the likely cause of toxicity in the Tijuana River. Tijuana River was identified as a TIE candidate site based on the Triad Decision Matrix and TIE testing was conducted on the February 11 and 18, 2005 samples. These investigations were inconclusive due to the loss of toxicity in the unmanipulated sample at the time of testing. Heavy particulate load within the sample may have ameliorated the toxic effects of the sample by binding to the contaminants. Non-polar organic compounds were identified in the 2002-2003 and 2003- 2004 TIE testing. Diazinon was the suspect contaminant in these testing periods as determined by methanol fractionation procedures. Stream Bioassessment Stream bioassessment monitoring in the Tijuana River WMA included two lower urban affected sites, one in Campo Creek and one on the Tijuana River at Dairy Mart Road, and one reference site on Wilson Creek. The Campo Creek site is upstream of any influence from the City of Tijuana and surrounding communities and is not representative of the lower reaches of the Tijuana River directly affected by runoff from these communities. The Index of Biotic Integrity rating for Campo Creek was Very Poor for EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-19 both surveys, but there were several organisms collected that were otherwise found only at reference sites. The Tijuana River site had an IBI rating of Poor in May (the site was not sampled in October due to dry conditions) and the IBI rating for the reference site was Fair. Ambient Bay and Lagoon Monitoring Sediments in the Tijuana River Estuary were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COCs were most likely to be found (i.e., those with the highest TOC and smallest grain size). These sites were sampled in Phase II of the assessment and sediments were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven metals (arsenic, cadmium, chromium, copper, lead, nickel, and zinc) common to all embayments were also found in the Tijuana River Estuary sediments. Sediment chemistry data were compared to the ERL and the ERM data. These values (ERL and ERM) are for comparison purposes only and are not water or sediment quality objectives. Of the metals detected, concentrations were low and none exceeded their respective ERLs. In addition, there were no PAHs, PCBs, or pesticides found in the Estuary above the detection limit. The mean ERM-Q for the Tijuana River Estuary was 0.128 which exceeds the ERM-Q threshold of 0.10. Percent survival of E. estuarius exposed to Tijuana River Estuary sediments was 97% and was not significantly different from that of the control, suggesting that the sediments were not toxic to the test organisms. Benthic community indices suggested that the biotic community in Tijuana River Estuary was intermediate compared to the other embayments assessed. The infaunal community was co-dominated by three taxa: a polychaete worm, a genus of clam that was unique to the Tijuana River Estuary, and a gammarid amphipod. For the Tijuana River Estuary, the relative ranks were seven for chemistry, two for toxicity, and six for benthic community structure. The relative quality in the Tijuana River Estuary decreased in 2004 compared with the 2003 ranking. WMA Assessment For the Tijuana River WMA, TSS, turbidity, all three bacterial indicators, and Diazinon were identified as high frequency of occurrence COC, followed by BOD, COD, ammonia, and total phosphorus which were identified as medium frequency of occurrence COC, and MBAS, dissolved phosphorus, Chlorpyrifos, Malathion, and total copper were identified as low frequency of occurrence COC. The elevated densities of all three bacterial indicators and elevated levels of BOD, COD, and nutrients (un- ionized ammonia as N and total phosphorus) are indicative of wastewater discharges. Pesticides have also had persistent exceedances of water quality objectives in the watershed. Stream bioassessment monitoring rated the Tijuana River site as Poor, but the investigators in this study feel that this rating is much higher than the actual benthic community quality suggests. The two other bioassessment sites are upstream of any influence from the City of Tijuana and surrounding communities and are not representative of the lower reaches of the Tijuana River directly affected by runoff from these communities. Based on the triad decision matrix, there was evidence of persistent water quality objective exceedances, there was evidence of persistent toxicity, and indications of benthic alteration. The TIEs conducted in 2003-2004 confirmed initial results performed in 2002-2003 indicating Diazinon and methyl dihydrojasmonate were the primary contributors of toxicity in the Tijuana River. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-20 The BLTEA rating priorities agreed with the WMA assessment findings for the Tijuana Valley sub- watershed but since this sub-watershed is only 7% of the entire Tijuana River WMA, it suggests that the high priorities and COCs may be more localized to the area near the MLS. The Tijuana River WMA did not have any high priority (A) ratings for the overall WMA. The highest rated constituents were sediments, nutrients, gross pollutants, bacteria, and benthic alteration which were all given a B rating. ES.5 Regional Assessments ES.5.1 Cross Watershed Comparison Comparisons between watersheds were performed using several different statistical tools, including scatterplot analysis, regression analysis, analysis of variance (ANOVA), multivariate cluster analysis, and multiple regression. Summary of Statistical Analyses The single event and annual mean concentrations for key constituents and toxicity at Tijuana River MLS were statistically different and had higher magnitude of exceedances of WQO compared to all the other MLS, particularly those associated with untreated wastewater and highly urbanized land use. The constituents that consistently exceeded the WQO include fecal coliform, TSS, turbidity, BOD, ammonia, total phosphorus, and Diazinon. This is a finding that has been consistent throughout the past four years of monitoring. This MLS has also had the most consistent toxicity results with toxic reactions for all tests except those for Selenastrum. Notable patterns seen at other MLS include lower concentrations of Diazinon than observed in earlier years; decreasing trends for total lead, total cadmium, ammonia, and BOD at Tecolote Creek; increasing turbidity and nitrite in Chollas Creek, and increasing TSS, COD, turbidity, TKN, phosphorus, lead and fecal coliform at Agua Hedionda Creek. On a regional basis, TSS annual mean concentrations have exceeded the WQO in 7 of the 11 MLS over the last four years indicating that TSS, which is an indicator of sediment loading, is a regional water quality issue. Across watersheds, the highest exceedances were observed for the 2004-2005 period which corresponds to the year of greatest precipitation. Larger and greater intensity storm events will mobilize a greater amount of sediment that would then correlate to greater TSS concentrations. Higher TSS may be associated with an increase in land disturbance activities in the watershed, and increased impervious areas upstream of creek and river sections that may be subject to bank erosion from greater and more sustained peak flows. Temporal patterns in TSS concentrations indicate higher concentrations during greater intensity storm events. Cluster analysis showed the differences between Tijuana River and the other MLS primarily, followed by differences between years which may be related to the differing amounts of rainfall in the past four years. Relationships between toxicity and COC based on the four years of data showed strong relationships for increasing toxicity with higher amounts of Diazinon, TSS, and dissolved nickel. Strong relationships based on the threshold analysis were also found for Diazinon. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-21 ES.5.2 Storm Water Modeling ES.5.2.1 Static Storm Water Modeling Static storm water modeling, described here, predicts average flows and contaminant concentrations based on watershed characteristics. Predicted pollutant loads and event mean concentrations (EMCs) expected from mass loading stations were calculated using a spreadsheet model. The static pollutant loadings model consists of a Microsoft ExcelTM spreadsheet that calculates annual pollutant loads expressed in pounds per year. The loadings and EMCs were estimated based upon land use types within the mass loading station watersheds, associated EMC values representative of each land use, and volume of runoff from the watershed. The spreadsheet was used to estimate annual runoff pollution loads and EMCs for the following constituents: nutrients (dissolved phosphorus and total Kjeldahl nitrogen); selected heavy metals (lead, copper, zinc, and cadmium); oxygen demand (BOD5 and COD); and total suspended solids (TSS). Estimated chemical oxygen demand matched measured concentrations for most mass loading stations. However, measured COD values were much higher than estimated values at Chollas Creek, Agua Hedionda Creek, the San Diego River, and the Tijuana River during storm events, which may be indicative of potential sewage spill or overflow. Other monitoring stations had lower variability and concentrations closer to the modeled value. Dissolved phosphorus had measured EMC values that were higher than the modeled values. Measured values of dissolved phosphorus during all three events at the Tijuana River and Agua Hedionda Creek were well above the estimated concentrations. Estimated total suspended solid concentrations were very close to values measured during monitored storm events for many of the mass loading stations. The Tijuana River and Agua Hedionda Creek mass loading stations had a high degree of variability in TSS measurements between storms and all measured values were above estimated concentrations calculated from the model. Other stations had results that were often relatively low as estimated by the model. The model predicts slightly higher concentrations of total copper from drainage areas that are highly urbanized. Most measured values were close to the predicted ones. However, the Chollas Creek mass loading station had a measured copper concentration during the October 17, 2004 storm that was several times higher than the estimated concentration. The primary factor influencing water quality in the static model is land use while the primary factor in calculation of the mass load emanating from each hydrologic unit is contributing area. A secondary, but significant factor for mass loading is annual precipitation. While the EMC model appears to estimate chemical oxygen demand, total Kjeldahl nitrogen, and dissolved phosphorus well, the potential for improvements in the model exists in estimates for metals. The model predicts higher EMCs for metals during wet weather compared to the actual measurements. Observations based on the model help provide quantitative support to the intuitive concept that pollutant reduction strategies should: EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-22 1. Focus on improving water quality emanating from particular watersheds by developing and implementing BMPs that are designed to specifically reduce pollutants associated with certain land uses. 2. Focus sediment and pollutant accumulation monitoring activities below areas that drain large watersheds where the largest potential pollutant loads are expected. ES.5.3 Dry Weather Data Analysis Results The data used in this assessment was collected from May 1 through September 30, 2004. Among individual watersheds and jurisdictions, the number of sites monitored and the sampling frequency varied. Several reasons that account for this variability between watersheds are the number of jurisdictions implementing the program, the number of sites monitored by each individual jurisdiction, and the number of sub-watersheds. In each of the monitored watersheds, the number of exceedances also varied, resulting in a range of total exceedances per watershed from 2 for the Tijuana River area to as many as 133 for Carlsbad. During the 2004 monitoring period, 485 samples exceeded established dry weather action levels. This sample volume has increased significantly since the 2003 monitoring period, when 373 samples exceeded. The parameter which most frequently exceeded was total coliform, which accounted for 114 (23.5%) of all exceedances. Turbidity and enterococcus were the next highest, with respective contributions of 15.9% and 12.6%. Other parameters which each individually contributed 10-5% of the exceedances were ammonia, nitrate, orthophosphate, and fecal coliform (in descending order). The remaining parameters contributed to less than 5% of the total exceedances combined (conductivity, pH, dissolved copper, MBAS, Diazinon, oil and grease, dissolved cadmium, and Chlorpyrifos). There were no exceedances of dissolved lead or zinc. Comparison of current data to that collected in 2002 and 2003 reveals several clear trends in the frequency of various contaminant exceedances based on major land use categories. In comparing residential, commercial, industrial, and agricultural land uses, it is apparent that total coliform has frequently exceeded water quality objectives during the past three years of monitoring. Specifically for the residential and commercial categories, total coliform has been the first ranked COC during all three years. Also notable are the frequent exceedances for fecal coliform, enterococcus, and turbidity. Though it did not appear as a priority COC for any of the land uses in 2004, fecal coliform ranked second in 2003 for residential and commercial, and third for residential (2002), industrial (2002 and 2003), and agriculture (2003). Enterococcus was also consistently high, with rankings of first for commercial in 2002, second for industrial (2003 and 2004) and residential (2002), and third for residential (2003 and 2004) and commercial (2004). Turbidity was the second most frequently exceeded parameter for all the land uses in 2004. In addition, it was ranked second in 2003 for industrial and agricultural land uses. Comparison of the 2003 and 2004 dry weather data by land use reveals some minor change in the COC found in the major land use categories. The potential benefits of annually updating the list of COC by land use category are: • the ability to assess the effectiveness of structural BMPs • the ability to select non-structural BMPs (outreach) • customizing inspections EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-23 • predicting water quality impacts • determining overall changes in the prevalence of COC The Municipal Separate Storm Sewer System (MS4) conveyance type at each dry weather sampling location was logged by each jurisdiction. Based on the 8 conveyance types, sites were categorized by construction material as either natural or manmade. Representing the data in this way allows for the identification of the most prevalent pollutants by type of MS4 conveyance system. The natural conveyance systems had notable exceedances for total coliform, turbidity, and nitrates, with proportions of 10%, 18%, and 20%, respectively. About half of the sampling sites for natural conveyances were associated with agricultural or rural residential land uses which may account for the higher frequencies for nitrate; the higher turbidity is likely due to the potential for erosion in earthen waterways. The manmade conveyance systems had exceedances at 10% or more stations of seven parameters. Ammonia, nitrate, and orthophosphate exceeded at 10-20% of the sites, while turbidity exceeded at approximately 27% of the sites. The fecal coliform WQO was exceeded at 13% of the sites, whereas total coliform exceeded the WQO at 42% of the sites and 23% of sites had exceedances of enterococcus. The two parameters that consistently exceeded throughout all conveyance types were total coliform and turbidity. The potential benefits of annually updating the list of COC by MS4 conveyance type are: • selecting BMPs for each type based on pollutants found • selecting cleaning procedures or methods to target pollutants by MS4 type • using land use and conveyance type COC data to minimize water quality impacts from new development • prioritizing cleaning frequency of MS4 based on COC in the sub-watershed and/or 303(d) listings ES.5.4 Rapid Stream Bioassessment Results A total of 27 different stream monitoring reaches were assessed in San Diego County in the surveys of October 2004, and May 2005. Four of these sites were considered to represent reference conditions. A total of 49 different monitoring reaches have been sampled since May 2001. Taxonomic identification of samples collected October 2004 produced 110 taxa from a total of 18,460 individuals. The May 2005 samples produced 91 taxa from 21,534 individuals. The most abundant organisms in October 2004 in the study region were the black fly, Simulium; Chironomid midges; the amphipod, Hyalella; Ostracods (seed shrimp), and Oligochaetes (earthworms). The most abundant organisms in May 2005 in the study region were the black fly, Simulium; the mayfly, Baetis; Chironomid midges; Oligochaetes, and the mayfly, Fallceon quilleri. The majority of organisms from the urban affected sites were moderately or highly tolerant to stream impairments. Organisms highly intolerant to impairments were encountered infrequently at the urban affected sites, but their presence even in low numbers is significant. Non-reference sites that supported highly intolerant organisms included San Dieguito River-Del Dios Highway and Santa Margarita River-Willow Glen Road. The Index of Biotic Integrity ratings of the monitoring sites ranged from Very Good to Very Poor in October 2004 and May 2005. IBI scores for the reference sites were always higher than the scores for the urban influenced sites. The May 2005 survey produced consistently lower IBI scores across the entire region than in the October 2004 survey. Comparison of IBI scores with the in-stream physical habitat quality of the monitoring reaches indicated a poor correlation between habitat quality and benthic macroinvertebrate community quality. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-24 Of all of the watersheds in San Diego County, the Santa Margarita River Watershed was the least impacted. The remaining watersheds have substantially greater amounts of urbanization, and the IBI results generally indicate that greater water quality impacts occur in the lower portions of the watersheds, as the impacts of urban runoff become cumulative. After 4½ years of bioassessment surveys, long-term trend analysis is becoming possible. The most significant observation is that the macroinvertebrate community quality has not shown any trend towards degradation or improvement. IBI scores for most of the San Diego sites were similar between May 2001 to May 2005. Individual seasons or years have produced varying conditions for the macroinvertebrates, and many of the monitoring sites have shown a parallel response to the variability of the conditions. ES.5.5 Ambient Bay and Lagoon Monitoring In the summer of 2004 sediments in the twelve major coastal embayments in San Diego County were monitored to assess the potential for adverse effects from the watershed and to compare sediment quality among the embayments. In Phase I, a stratified random approach was used to identify the three sites in each embayment where COCs were most likely to be found (i.e., those with the highest TOC and smallest grains size). Buena Vista Lagoon had a much higher percentage of TOC and fine grained sediments than the other embayments. In contrast, sediments in the Santa Margarita River Estuary contained a much lower TOC content and percentage of fine-grained particles than the other embayments. This pattern was also seen in the 2003 ABLM sampling. In Phase II of the assessment, the three sites identified in Phase I for each embayment were sampled and analyzed for chemistry, toxicity, and benthic community structure. For the chemistry assessment, composite sediment samples from each embayment were analyzed for metals, PCBs, PAHs, and pesticides. PCBs, PAHs, and pesticides were not detected in any of the embayments. A suite of six metals was found in all 12 embayments: arsenic, chromium, copper, lead, nickel, and zinc. In general, concentrations of metals were low in all embayments and there were no metals that exceeded their ERM thresholds. However, several metals exceeded ERL values, including copper (exceeded the ERL at three sites), arsenic (exceeded the ERL at four sites), zinc (exceeded the ERL at three sites), and lead (exceeded the ERL at one site). The mean ERM-Q value, which represents the cumulative impact from all COCs for which ERMs are available, was greatest at Mission Bay and Oceanside Harbor and lowest at the Santa Margarita River Estuary and San Elijo Lagoon. For the toxicity assessment, the percent survival of a marine amphipod exposed to sediments from each of the embayments was compared to that of a control. Percent survival was not significantly different from that of the control for ten embayments: the Santa Margarita River Estuary, Oceanside Harbor, the San Luis Rey River Estuary, Buena Vista Lagoon, Agua Hedionda Lagoon, San Elijo Lagoon, Los Peñasquitos, Mission Bay, Sweetwater River Estuary, and the Tijuana River Estuary. The two remaining embayments where percent survival was significantly different from that of the control were Batiquitos Lagoon and San Dieguito Lagoon. For the benthic community assessment, animals collected from the sediment at three sites in each embayment were identified to the lowest possible taxonomic level. Several indices of benthic community structure were then calculated, including abundance, richness, diversity, evenness, and dominance. For each embayment the scores from these indices were ranked and the summed ranks were used to compare the benthic communities among the 12 embayments. Based on this overall ranking, the EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-25 embayments with the best relative benthic communities were Mission Bay, Sweetwater River Estuary, Batiquitos Lagoon, Oceanside Harbor, the Santa Margarita River Estuary, and San Dieguito Lagoon. Those with the worst relative benthic communities were Buena Vista Lagoon, Agua Hedionda Lagoon, Los Peñasquitos Lagoon, the Tijuana River Estuary, the San Luis Rey River Estuary, and San Elijo Lagoon. The experimental design for the ABLM Program was based on a presumed positive correlation between COC, TOC content, and grain size, where higher COC concentrations are expected in areas with higher TOC and smaller grain size. The results of the ABLM Program indicate a strong, positive relationship between mean ERM-Qs, TOC content, and percentage of fine-grained sediments. These results help validate the approach utilized in the ABLM Program. However, the relationships between sediment chemistry, toxicity, and benthic community structure were weak. This is likely due to the dynamic nature of coastal estuaries and a limited number of samples and analyses. Results from samples collected in subsequent years of the ABLM Program may help to strengthen these relationships. ES.5.6 Coastal Outfall Data The data used in this assessment was collected from April 1, 2004 through March 31, 2005 by the Copermittees. Coastal Outfall Data Analysis Results for San Diego County During the 2004-05 coastal outfall monitoring period, 35 stations were monitored from San Diego County beaches with paired samples (one from the shore and one from the storm drain) and were analyzed for bacterial indicators. The data evaluated for this monitoring period indicate that there are occasional bacterial exceedances in the receiving water and storm drain outfall sampling locations and in the coastal outfall program receiving water sampling stations. Coastal Lagoon Outfall Data Analysis Results for San Diego County During the 2004-05 coastal lagoon outfall monitoring period, 25 stations were monitored from San Diego County lagoon outfalls and/or receiving waters and were analyzed for bacterial indicators. In some cases, paired samples (one from the storm drain and one from the shore) were collected. During dry weather eight outfalls had exceedances of at least one bacterial indicator in both the storm drain and receiving water samples. There were no exceedances in any of the samples collected during wet weather. ES.5.7 Third Party Regional Data The Padre Dam Water Quality Monitoring Program for 2004 was comprised of six stations, including three located on the San Diego River, two on tributary creeks (Forrester Creek and Sycamore Creek), and one station on one of the Mission Ponds. Water samples are collected for 13 analytical measurements and 8 field measurements. Sediment samples were also collected at these sites. Exceedances were noted for dissolved oxygen, turbidity, E. coli, fecal coliform, and TDS. The most notable result was the 91.7% exceedance rate (11 exceedances out of 12 samples) for TDS in Forrester Creek. In addition, all six stations exceeded the WQO for fecal coliform in the month of December, and five stations also exceeded the WQO for E. coli. EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-26 ES.6 Program Review During the 2001-01 permit issuance, the Copermittees were required to review historical data and develop future recommendations. This was developed in the “San Diego Region Previous Storm Water Monitoring and Future Recommendations Report” (MEC 2001). The program design that was implemented in the 2001-2002 permit year was intended to provide: • Information relating to chemical, physical, and biological impacts to receiving waters resulting from urban runoff, • Indication of the overall health and long-term trends in water quality in the receiving waters. To date these two over-arching goals have been met by the monitoring design, however, additional questions resulting from the collected data have yet to be answered. Such questions include “What are the dry weather (ambient) concentrations of the urban runoff constituents?” and “How do the constituents of concern vary throughout the watershed?” Since the 2001-2002 monitoring year (the first year of monitoring under Order 2001-01) significant information has been gathered about each watershed management area in San Diego County under the monitoring program and associated assessments. This information forms the basis of existing knowledge about water quality that was not available for all watershed management areas prior to 2001-2002. Using this information, the Copermittees can refine their monitoring program to better address specific management questions and yield more baseline information against which improvements in water quality can be measured. As the Copermittees enter into a new permit cycle in 2006-2007, it presents an opportune time to reassess the existing monitoring program together with the management questions to define the future monitoring program approach for the next permit cycle. ES.7 Recommendations The recommended actions from the triad assessments are summarized in Section 14. All watersheds should continue water quality monitoring to gather long-term trend information and upstream sources of contaminants should be investigated. In addition, TIEs in Chollas Creek and Sweetwater River should be conducted. Additional recommendations for 2005-2006 are to conduct a qualitative assessment of streambank erosion around mass loading and stream bioassessment stations, as well as to monitor for organochlorine and organophosphate pesticides, PAHs, PCBs, and synthetic pyrethroids at the Ambient Bay and Lagoon sampling locations. The recommended program for 2007-2010 will advance the understanding of conditions in San Diego County watersheds. It is a holistic program that uses both a weight-of-evidence plus a compliance approach. The program is designed to better address the five Stormwater Monitoring Coalition (SMC) key management questions and provide an integration with the jurisdictional dry weather IC/ID program. Through segmenting the watersheds and adding new stations it will provide additional watershed information relative to magnitude and extent, as well as provide increased spatial coverage to focus management efforts. Linkage with the jurisdictional dry weather IC/ID program and watershed segmentation will provide a better mechanism to identify potential sources. Further, the recommended program provides an integration of program elements, including wet and dry weather monitoring, upstream watershed assessments, bioassessment monitoring, triad assessment, and ABLM monitoring, while resulting in little loss of the ability to detect trends. The program will strive to encourage pollution prevention, storm water educational outreach, and source control measures. Moreover, the EXECUTIVE SUMMARY 2004-2005 Urban Runoff Monitoring Report ES-27 recommended program provides a more comprehensive view of the watersheds with the addition of dry weather monitoring to complete the loading picture and provide increased information value for future TMDLs. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-1 1.0 INTRODUCTION 1.1 Background National Pollutant Discharge Elimination System (NPDES) permitting requirements are mandated by the Federal Clean Water Act (CWA). In 1987, the CWA was amended by the Water Quality Act to require the U.S. Environmental Protection Agency (EPA) to develop discharge permits under the NPDES program. In California, the municipal permit program is overseen by the State Water Resources Control Board (SWRCB) and Regional Water Quality Control Boards (RWQCB) in accordance with the November 1990 Federal Regulations (40 CFR Part 122) and the Porter-Cologne Act. These regulations require all municipal separate storm sewer systems (MS4s) that serve populations over 100,000 to obtain coverage under an NPDES discharge permit. In the San Diego area, the San Diego Regional Water Quality Control Board (RWQCB) oversees the NPDES permit program. The County of San Diego, the City of San Diego, the San Diego Unified Port District, the San Diego Regional Airport Authority and 17 other cities (collectively referred to as Copermittees) are covered under a municipal NPDES permit for discharge of urban runoff to waters of the United States. The participating Copermittees share the costs of monitoring required for compliance with this permit. Copermittees include: Cities: Carlsbad Chula Vista Coronado Del Mar El Cajon Encinitas Escondido Imperial Beach La Mesa Lemon Grove National City Oceanside Poway San Diego San Marcos Santee Solana Beach Vista County: Unincorporated areas of San Diego County within the Urban Limit Line Other: San Diego Unified Port District San Diego Regional Airport Authority (added as a Copermittee on August 13, 2003 under Addendum No. 1 to Order 2001-01) This report provides a summary of the 2004-2005 Receiving Waters Monitoring Program for the Copermittees identified as dischargers of urban runoff in Order No. 2001-01 (the permit) of the RWQCB, and fulfills the requirements of Order No. 2001-01 Attachment B, IV, Submittal of Receiving Waters Monitoring Requirements. Order No. 2001-01 requires the implementation of a countywide or watershed-based Receiving Waters Monitoring Program that includes the following components: ♦ Urban Stream Bioassessment Monitoring ♦ Long-term Mass Loading Monitoring ♦ Coastal Storm Drain Outfall Monitoring ♦ Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring ♦ Toxic Hot Spots Monitoring in San Diego Bay. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-2 The Core Receiving Waters Monitoring Program was developed by the Copermittee Monitoring Workgroup and described in the Previous Monitoring and Future Recommendations Report (MEC 2001) required by the permit. The three elements of the recommended monitoring framework include: Regional Monitoring Programs that provide baseline datasets for comparing information from local monitoring programs. These programs encompass a large spatial area (e.g., San Diego Region, entire southern California bight), and look at many elements potentially impacted by storm water runoff. This type of monitoring takes a long-term view of the ultimate receiving waters, the coastal bays, lagoons, and the ocean. Regional monitoring is designed to answer questions concerning the ecological health of a large geographic region and encompass numerous components, including water and sediment quality, fish, benthos, birds, etc. An example of regional monitoring is the Southern California Coastal Waters Research Project (SCCWRP) Bight Monitoring that is conducted every five years. Core Monitoring is long-term monitoring with the objective of tracking compliance with regulatory requirements or limits, or to track trends over time. Core monitoring programs typically involve sampling at fixed stations that are sampled routinely through time. Individual monitoring components are designed to evaluate the long-term changes in water quality and mass loading to MS4 and receiving waters. Assessing concentrations of chemical constituents, toxicity to test organisms, and benthic assemblages provides indications of long-term trends and effects between and within watersheds. Special Studies supplement both the Core Monitoring and the Regional Monitoring. Special Studies are focused evaluations designed to answer specific questions. These are typically short-term efforts intended to answer specific questions that may be raised during assessment of core monitoring results. Some examples of Special Studies include evaluation of the link between storm water discharges and Toxic Hot Spots, conducting DNA-ribotyping for bacterial source identification in a watershed, and source identification studies used for the development of Total Maximum Daily Loads (TMDLs) for 303(d) listed impaired waterbodies. This report summarizes the results of monitoring activities that took place in 2004-2005. The primary short-term objectives of the Core Receiving Waters Monitoring Program activities are to: ♦ Determine the ecological health of receiving waters in the county based on chemical, physical, and biological evidence. ♦ Assess compliance with RWQCB order No. 2001-01. The long-term objectives include: ♦ Predict short- and long-term impacts to receiving waters that result from changes in land-use within each watershed, and provide data that can be analyzed to develop pollutant reduction strategies for those impacts. ♦ Measure the effectiveness of Urban Runoff Management Plans (URMPs) and other potential pollutant reduction strategies. ♦ Develop and implement a program that integrates with other regional programs involved in assessing the overall health of receiving waters in San Diego County and Southern California. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-3 1.2 Monitoring Program History The San Diego Regional Storm Water Monitoring Program was first mandated by the RWQCB under Order No. 90-42, NPDES Permit CA 0108758 issued on July 16, 1990 and implemented in 1993-1994. This permit was scheduled to expire on July 15, 1995; however, coverage was extended pending the issuance of a new permit. To facilitate continuation of monitoring activities, revised monitoring requirements were published on October 31, 1995 under the RWQCB Monitoring and Reporting Program Order No. 95-76. Alterations to Order No. 95-76 were made through Technical Change Order No. 1, published in January 1996. Changes to the program implemented during wet-weather season 1998/99 were authorized under Technical Change Order No. 2, dated December 3, 1998. Technical Change Order No. 3 addressed changes to the program during the 1998/1999 wet-weather season. Technical Change Order No. 4 documents program changes for the 1999/2000 wet-weather monitoring effort. On February 21, 2001 the RWQCB adopted a new permit for the region, Order No. 2001-01. The following is a chronological summary of storm water monitoring programs in the San Diego region over the past ten years from the Previous Storm Water Monitoring and Future Recommendations Report (MEC 2001). Emphasis is placed on reviewing the progression of monitoring objectives and methodologies. 1.2.1 1993-1994 Objectives and Key Elements The primary objective of this program was to measure pollutant concentrations and provide preliminary estimates of pollutant loads for use in establishing storm water management program priorities (Kinnetic Laboratories 1994). The first year’s monitoring program was designed by a task force of the Copermittees, and approved by the RWQCB. Storm water monitoring in the 1993-1994 season was performed at 15 sites. Each of these sites utilized flow-composited storm water monitoring stations. Six sites with relatively small catchments and one dominant land use per drainage were classified as land use stations. Different land uses that were evaluated include residential, commercial, industrial, and construction. The purpose of these land use stations was to identify the concentration of constituents of concern (COC) that result from the net effect of activities within each different land use type. Two construction sites and seven mass loading stations (MLS) were also monitored in the 1993-1994 season. These MLS were selected to directly measure pollutant loading for typical storm events from major watersheds. Criteria for selecting which watersheds would be monitored included choosing those with more populated urban portions of the region and those jurisdictions that discharge into the bays and coastal ocean waters. Land use sampling station sites included: ♦ Residential Sites – Jeremy and Park ♦ Commercial Sites – Wal-Mart and Yuma ♦ Industrial Sites – Vernon and Yarrow ♦ Construction Sites – Top Gun and Proctor Mass loading sites included: ♦ Carroll ♦ Rose ♦ Tecolote Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-4 ♦ San Diego River ♦ Switzer ♦ Chollas ♦ Otay The primary variable used to assess COC concentrations from storm water data collected during the 1993-1994 season was the event mean concentration (EMC). The EMC was defined as the total pollutant load divided by the total runoff volume per storm event. EMC estimates were directly assessed by measurement of COC concentrations in the flow-weighted composite samples, which is a mechanical technique of obtaining the values. The 1993-1994 monitoring program mandated collection of two storm events at each of the 15 sites. The storm water data collected in the 1993-1994 season was compared against the Nationwide Urban Runoff Program (NURP) data (EPA 1983), land use water quality data from other regional studies in California, and water quality objectives adopted in the Water Quality Control Plan for the Inland Surface Waters of California (ISWP). The results of the land use monitoring in San Diego County showed: ♦ Lead concentrations in San Diego County were lower than NURP estimates, while the concentration of most other metals was comparable to the results of NURP sites. ♦ San Diego County nutrient data was elevated compared to similar regional sites. ♦ Concentrations of bacterial indicators were high, but in line with NURP data. 1.2.2 1994-1995 Objectives and Key Elements The RWQCB issued a new Monitoring and Reporting Program on June 30, 1994 for the second year of the San Diego Regional Storm Water Monitoring Program. This program was similar to the first year’s program, but included additional land use stations and eliminated some of the previous mass loading stations. Toxicity testing and sampling and testing of sediments in Chollas Creek and the nearby San Diego Bay sediments were also added. Construction site monitoring was also eliminated. The primary objectives of the storm water monitoring program for the 1994-1995 season (Kinnetic Laboratories 1995) were: ♦ Directly measure pollutant loadings during typical storm events from highly urbanized San Diego area watersheds that discharge directly into important bay and stream receiving waters. The purpose of these stations was to evaluate area-wide contributions of storm water pollutant loadings to receiving waters. ♦ Characterize storm water runoff discharges from small, relatively homogeneous drainages identified as representative of residential, commercial, and industrial land use activities within San Diego County. The purpose of gathering these data was to identify and monitor the effectiveness of specific best management practices (BMPs) associated with land use activities (however, these specific BMPs are not addressed in the final report). Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-5 ♦ Investigate receiving water impacts by measuring aquatic toxicity of storm water runoff and sediments in San Diego Bay at the discharge area of one of the urban creeks (Chollas Creek). While the 1993-1994 monitoring program mandated collection of two storm events at each of the 15 sites, the 1994-1995 monitoring program required three storm events at each of the 12 locations chosen for monitoring. Flow-weighted composites were taken and discharge volumes for each storm event were recorded. Grab samples were collected for measuring pollutant constituents in storm water not amenable to composite sampling techniques. EMC were calculated for each COC. Similar to the 1993-1994 season, data from the 1994-1995 season were compared against NURP data, land use water quality data from other regions, and water quality objectives. In addition, sediment samples from four locations within Chollas Creek and in San Diego Bay at the mouth of Chollas Creek were evaluated for physical, chemical, and toxicity attributes. New land use sites included Landis (residential), Bramson (commercial), and Crosby (industrial). The findings of the land use monitoring were similar to those in 1993-1994 with the addition that mean EMC data from San Diego County for copper were lower than NURP values. Nitrogen concentrations that were slightly elevated in 1993-1994 were reduced and consistent with NURP data in 1994-1995. 1.2.3 1995-1996 Objectives and Key Elements Storm water monitoring requirements for the 1995-1996 season were published on October 31, 1995 under tentative RWQCB Order No. 95-76. The objective of the monitoring and reporting program was to characterize storm water pollutant loading and concentrations, including long-term trends during the wet-weather season, which was defined as October 1 to April 30 of each year (Woodward-Clyde 1996). The 1995-1996 monitoring program consisted of sampling three storm events at 12 stations. Stations included nine land use and three MLS sites. The nine land use sites were clustered in three geographic areas including North County, South County, and a heavily populated urban area of the City of San Diego. MLS were located at Tecolote, Switzer, and Chollas Creeks. The list of analytes specified in Order No. 95-76 included many of those chemicals listed under 40 CFR 122, Appendix D, Table II and III, as well as pollutant indicators listed in 40 CFR 122.26(d)(2)(iii)(A)(3). Those analytical parameters are listed in Table 1-1. For this wet-weather season, Technical Change Order No. 1 authorized the analysis for Total Recoverable Metals instead of Dissolved Metals. Pre- and post-wet season sediment samples were taken upstream of the MLS location in Chollas Creek and at the mouth of Chollas Creek in San Diego Bay to evaluate storm water effects on the receiving water environment by assessing bottom sediments. Samples were collected within the two-week periods prior to October 1, 1995 and after April 30, 1996 in accordance with tentative RWQCB Order No 95-76. Physical, chemical, and toxicity analyses were performed on the sediment samples as specified in the RWQCB Order. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-6 Table 1-1. Analytical requirements for each type of monitoring site as specified in RWQCB Order 95-76 (Woodward-Clyde 1998). Monitored Station Designation Constituent Land Use Mass Loading Creek and Bay Sediments General Physical and Inorganic Non-Metals z z Total Dissolved Solids (TDS) z z Total Suspended Solids (TSS) z z Turbidity z z Total Hardness z z pH z z Specific Conductance z z Temperature z z Total Phosphorus z z Dissolved Phosphorus z z Nitrate and Nitrite z z Total Kjeldahl Nitrogen (TKN) z z Ammonia z z Total Cyanide z z Biological Oxygen Demand, 5-day z z Chemical Oxygen Demand z z Percent Solids z Grain Size z Organics Total Petroleum Hydrocarbons z z Oil and Grease z z Total Phenols z z Acid/Base/Neutral Extractable Compounds z z z Chlorinated Pesticides z z z Methylene Blue Active Substances z z Total Organic Carbon z Metals, Total Recoverable Antimony z z Arsenic z z z Beryllium z z Cadmium z z z Chromium z z z Copper z z z Lead z z z Mercury z z z Nickel z z z Selenium z z Silver z z z Thallium z z Zinc z z z Bacteriological Total Coliform z z Fecal Coliform z z Fecal Streptococcus z z Toxicity Ceriodaphnia dubia z Pimephales promelas z Eohaustorius estuarius z Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-7 1.2.4 1996 – 2000 Objectives and Key Elements The objectives of the Copermittee storm water monitoring program did not change significantly from those defined for the 1995-1996 permit year over the period covering 1996 through 2000. Changes in the administration of the program from 1996 through 2000 are summarized below. ♦ In 1996-1997, storm water monitoring was conducted at the previous nine land use stations and four MLS. Two of the MLS were monitored in the previous years. A new MLS on Chollas Creek replaced one that was tidally influenced, and new MLS were added at California Creek and Los Peñasquitos Creek at Sorrento Valley at the request of the RWQCB. The Switzer Creek location was eliminated because it was tidally influenced. Polycyclic aromatic hydrocarbons (PAH) were analyzed using ultra-low detection limits during the 1996-1997 wet-weather monitoring season as a one-time study to quantify the levels present in storm water runoff. The levels were generally one order of magnitude lower than those measured by the U.S. Navy in Paleta Creek and the Sweetwater River. The ultra-low detection limit PAH analysis was discontinued in subsequent years primarily because it was intended as a special study and the results did not warrant its continuation. ♦ The 1997-1998 monitoring program consisted of pre- and post-season sediment sampling at two locations and storm water sampling during rain events at 12 locations in San Diego County. The eight land use stations and four MLS monitored in 1997-1998 were the same stations monitored in 1996- 1997. ♦ In 1998-1999, the scope of the storm water monitoring program was changed significantly based on discussions and research by a Storm Water Monitoring Working Group of Copermittees that met during September and October in 1998 and again in the fall of 1999. The Storm Water Monitoring Program Working Group evaluated new ways to obtain useful data by conducting focused monitoring for wet-weather season 1999-2000. Recommendations from the group and documented in Technical Change Order Nos. 2 and 3 included: • Elimination of eight land use stations from the program, as the previous five years of monitoring data were determined to be adequate for modeling purposes. Monitoring was conducted at the four MLS monitored in the previous year. A fifth MLS (AH1 – Agua Hedionda), which also served as a bacteria monitoring station, and four other bacteria monitoring stations were added to the program for a focused monitoring study in the Agua Hedionda watershed to determine sources of fecal contamination in runoff. • Elimination of constituents that were non-detect in 90 percent or more of the samples analyzed (included most semivolatile organic compounds, all organochlorine pesticides and polychlorinated biphenyls (PCBs), total cyanide, total beryllium, silver, mercury, and thallium). • Addition of Diazinon and Chlorpyrifos as new parameters. • The amphipod Hyalella azteca was used when performing toxicity tests in lieu of the fish Pimephales promelas. ♦ For the 1999-2000 wet-weather season, the RWQCB approved the proposed program in Technical Change Order No. 4 to the Monitoring and Reporting Order 95-76 dated November 5, 1999. This provided for additional studies of Diazinon usage in San Diego County and follow-up bacterial source tracking studies in Agua Hedionda Lagoon and Watershed. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-8 1.2.5 2000-2001 Objectives and Key Elements The storm water monitoring conducted in the 2000-2001 storm season was conducted under Order 95- 76; however, Order 2001-01 was imminent and the Copermittees had several coordination meetings with the RWQCB to discuss the monitoring scope for the wet season. The Copermittees proposed a historical and statistical review of all prior years’ monitoring results. This review was to include recommendations for the design of the next five years of monitoring (refer to San Diego Region Previous Storm Water Monitoring Review and Future Recommendations, Final Report, submitted August 20, 2001). Until results of the historical review and design of the next five years of monitoring were completed, the MLS wet-weather monitoring sites were retained at the same five MLS as the prior year. The RWQCB requested the addition of stream health indicator studies at 23 stations pursuant to the California Department of Fish and Game (CDFG) Rapid Stream Bioassessment (RSB) Monitoring Program to supplement on-going monitoring in other areas of the County by the CDFG. Sediment sampling at Chollas Creek both upstream and in San Diego Bay was conducted in October prior to the wet season. Post-wet season sampling in Chollas Creek and San Diego Bay was not conducted in order to allow Copermittees to provide sampling in support of the San Diego Bay Toxic Hot Spot Working Group (THSWG). The group was working on a monitoring study design to be conducted by SCCWRP and the US Navy. The RWQCB agreed to allow the Copermittees to direct resources at providing supplemental monitoring to the THSWG in lieu of monitoring post-wet season in 2001. The Copermittee monitoring support to the THSWG consisted of the collection of fine grain accumulated sediments within upstream reaches of Chollas and Paleta Creeks to assess contaminants available for discharge to the Bay during storm events. 1.2.6 2001-2002 Objectives and Key Elements Order 2001-01 was adopted in February 2001 and the 2001-2002 monitoring season was conducted under this document. The Copermittee's activities in the 2001-2002 monitoring year included the following activities. Details of each activity are provided in the following pages. ♦ Chemical and toxicity testing of storm water runoff from 12 MLS located within major watersheds of the County of San Diego. ♦ Rapid stream bioassessments at 23 stations in Fall 2001 and Spring 2002. ♦ Development of an ambient bay and lagoon monitoring program using information from other bay and lagoon monitoring studies performed in southern California. ♦ Coastal outfall monitoring. ♦ Toxic hot spot monitoring. The primary objective of this monitoring program was to determine the ecological health of receiving waters in the region based on chemical, physical, and biological evidence. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-9 1.2.6.1 Water Quality Monitoring at the Mass Loading Stations Twelve MLS were monitored during the wet-weather season over three separate viable storm events. A storm event was considered viable with a minimum of 0.1 inch of rainfall. Per RWQCB guidance, each storm of at least 0.1 inch of rainfall was separated by a minimum of 72 hours of rainfall, and the forecasted storm volume was within ±50% of the average storm volume and duration for the region. The 12 MLS are located within the following streams: Santa Margarita River San Luis Rey River Agua Hedionda Creek Escondido Creek San Dieguito River Peñasquitos Creek Tecolote Creek San Diego River Chollas Creek Sweetwater River Otay River Tijuana River The monitoring at Santa Margarita River was performed by the Navy Public Works Center under the supervision of Storm Water/Solid Waste Branch Head, Camp Pendleton Marine Corps Base for security reasons. The MLS at Otay River did not receive any runoff during 2001-2002, therefore this site was not sampled. All sampling and analyses conducted at MLS were in accordance with applicable USEPA regulations and RWQCB guidance. One flow-weighted composite was collected along with one grab sample at each station during each storm. Grab samples were generally taken after the first hour of increased flow during the storm. The Santa Margarita and San Diego River monitoring stations were co-located with United States Geological Survey (USGS) flow measuring stations. Flow rates at the other stations were monitored using an American Sigma flow meter with an ultrasonic sensor and/or a submerged pressure transducer. The sensor continuously measured stage and relayed that information to the flow meter. The flow meter continually calculated flow rates by inserting the stage information into the preprogrammed discharge equation. Field crews measured the flow rate of streams at stations not rated using USGS stream profiling guidelines prior to the beginning of the storm season and periodically throughout the storm season. This was accomplished by manual rating techniques using a hand-held flow meter. The resulting discharge rates were used to calculate a discharge equation, which was utilized by the flow monitoring equipment at some stations. Other stations utilized velocity/stage measurements to calculate discharge rates. The flow-weighted composite water samples were analyzed for the following parameters: Inorganic chemicals – Ammonia, chemical oxygen demand (COD), total and dissolved phosphorus, nitrate, nitrite, total hardness, Total Kjeldahl Nitrogen (TKN), total dissolved solids (TDS), total suspended solids (TSS), turbidity, and methylene blue active substances (MBAS); Metals (Total and Dissolved) – Antimony, arsenic, cadmium, chromium, copper, lead, nickel, selenium, and zinc; Organophosphate pesticides – Diazinon and Chlorpyrifos; Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-10 Toxicity Testing - At each station using Ceriodaphnia dubia, Selenastrum capricornutum, and Hyalella azteca. Grab samples were analyzed for the following parameters: Temperature, pH, specific conductance, oil and grease, biological oxygen demand (BOD), total coliform, fecal coliform, and enterococcus. 1.2.6.2 Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring The objective of 2001-2002 ambient bay, lagoon, and coastal receiving water monitoring program was to design a program that would be implemented in the 2002-2003 monitoring year to assess the conditions in the receiving waters. The 2001-2002 effort focused on reviewing results from other studies conducted in lagoons and bays in southern California. This review provided initial information regarding monitoring methods and statistical designs to develop an effective monitoring program for the Copermittee Storm Water Program. 1.2.6.3 Rapid Stream Bioassessment Monitoring This task monitored stream health pursuant to California Department of Fish and Game (CDFG) Rapid Stream Bioassessment Monitoring (RSB) procedures. Sampling and analysis of substrate samples for benthic infauna from each of 20 bioassessment monitoring stations and three reference stations (established in 2001) were conducted. Field measurements included pH, temperature, dissolved oxygen (DO), conductivity, flow rate, percent gradient, sampling area physiography, and overall assessment of physical habitat (e.g., vegetative cover and bank stability) at each station. Samples were analyzed in the MEC taxonomy laboratory pursuant to the CDFG procedure. A 10% quality assurance check was performed on taxonomic identification by the CDFG laboratory. Sample data from all RSB Monitoring stations on the receiving waters within the jurisdictions of the Copermittees were analyzed. Multivariate assemblage analyses were conducted to simultaneously evaluate all the populations of benthic invertebrates to provide a relative assessment of ecological health. 1.2.6.4 Toxic Hot Spot Monitoring in San Diego Bay The California Bay Protection and Toxic Cleanup Program (BPTCP) 1996 report identified areas of sediment contamination, benthic community impairment and toxicity to marine organisms in San Diego Bay. Based upon findings in the report, five specific areas in San Diego Bay were designated as toxic hot spots. Most of the areas lie at the outlets of creeks or storm drains, suggesting urban runoff is contributing to sediment toxicity at the toxic hot spots. Subsequently, four of the five sites were placed on the State’s 303(d) list as impaired water bodies, leading to formal requirements for the establishment of TMDLs for those sites. In 1999, the U.S. Navy, the San Diego Unified Port District, and the City of San Diego formed a partnership, the Toxic Hot Spot Work Group (THSWG), to begin addressing these areas of concern. Monitoring for those sites was designed to support the development of TMDLs. For program consistency and to avoid duplicative efforts, the monitoring required by the permit was conducted within the context of and included the active involvement of the THSWG. The THSWG, working with the RWQCB and SCCWRP, developed a workplan to study two of the five toxic hotspots beginning in July 2001. This work was conducted by the U.S. Navy and SCCWRP and Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-11 focused on evaluating sediment chemistry, sediment toxicity, and benthic communities at the discharges of Paleta and Chollas Creeks. To augment the THSWG study, the Copermittees re-allocated monitoring efforts from the 2000-2001 wet-weather program’s sediment monitoring of Chollas Creek. In lieu of conducting the second sediment sampling at the mouth of Chollas Creek in San Diego Bay, sampling upstream at two locations in Paleta Creek and three upstream locations in Chollas Creek was performed. The sediment samples were collected upstream of tidal influence and just below main tributaries to provide initial screening information about potential sources of bedload sediment contamination available for transport downstream to San Diego Bay. Sediment samples were analyzed for the same chemical parameters as proposed in the U.S. Navy/SCCWRP work. The study performed by the Copermittees provides supplementary information useful to the SCCWRP/Navy investigation at both Chollas and Paleta Creeks in San Diego Bay. The THSWG will utilize the results of this initial Copermittee monitoring program to design the next phase of investigation in San Diego Bay. The THSWG monitoring process is designed to be adaptive and based upon questions and answers elucidated from the results of this initial study. 1.2.6.5 Coastal Outfall Monitoring Coastal Outfall Monitoring was conducted and reported by coastal jurisdictions. 1.2.7 2002 – 2003 Objectives and Key Elements The monitoring conducted in 2002-2003 continues the monitoring program initiated in the 2001-2002 storm season. 1.2.7.1 Water Quality Monitoring at the Mass Loading Stations Water quality monitoring at the MLS during the 2002-2003 wet-season was conducted following the methods described in Order 2001-01 and established during the 2001-2002 monitoring season. As indicated in the 2001-2002 Urban Runoff Monitoring Report, the MLS at Otay River never received any runoff; therefore, this station was removed from the 2002-2003 monitoring program. The Navy Public Works Center continued to perform monitoring on the Santa Margarita River. The 2002-2003 MLS were: Santa Margarita River (Navy Site) San Luis Rey River Agua Hedionda Creek Escondido Creek San Dieguito River Peñasquitos Creek Tecolote Creek San Diego River Chollas Creek Sweetwater River Tijuana River Total organic carbon (TOC) and dissolved organic carbon (DOC) were added to the analytical requirements for each sample. All other testing and analyses were similar to those performed in 2001- 2002 and were conducted in accordance with applicable USEPA regulations and RWQCB guidance. 1.2.7.2 Ambient Bay, Lagoon and Coastal Receiving Water Monitoring The 2002-2003 monitoring season was the second year of this program, but the first year for sample collection, analysis and reporting. The program was designed to monitor the greatest potential water quality impact from urban runoff in a bay or lagoon (embayment). Based on a literature review, areas with the smallest sediment grain size and greatest TOC were most likely to reveal the water quality Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-12 impacts to the receiving water. Due to spatial and temporal variability, these areas are not permanently fixed. Therefore an embayment was most effectively monitored with a two-phase sampling program. In Phase I the embayment was stratified and sampled randomly within strata. These samples were analyzed and ranked based on grain size and TOC concentrations. In Phase II three sites representing areas of finest grain size and highest TOC were selected and resampled. These samples were subjected to toxicological testing and chemical and biological analyses. The selected smaller suite of samples were then tested individually or as a single composite. Twelve coastal embayments were monitored. These included: Santa Margarita River Estuary Oceanside Harbor San Luis Rey River Estuary Buena Vista Lagoon Agua Hedionda Creek Batiquitos Lagoon San Elijo Lagoon San Dieguito Lagoon Los Peñasquitos Lagoon Mission Bay Sweetwater River Estuary Tijuana River Estuary 1.2.7.3 Rapid Stream Bioassessment Monitoring During the 2002-2003 monitoring season, the methods for the rapid stream bioassessment monitoring program remained the same as the previous year, with minor changes. First, the monitoring sites were re-located to be correlated with the mass loading stations. This was performed in order to sample two sites of the water body within each hydrologic unit that had a mass loading station. One site was located as far downstream as possible, and the other site was located as far upstream as possible and still be located within an urban runoff receiving area. In 2001-2002, the sites were co-located with sites previously monitored by CDFG. Data analysis was performed utilizing the San Diego Index of Biotic Integrity (IBI) score. This score provided a quantitative ranking of sites based on expected reference conditions. Originally, sites were relatively compared to each other utilizing the Benthic Macroinvertebrate Index (BMI). 1.2.7.4 Toxic Hot Spot Monitoring in San Diego Bay Toxic Hot Spot Monitoring was conducted outside of this monitoring program by the RWQCB, the Port of San Diego, and the City of San Diego in collaboration with SCCWRP and the US Navy. 1.2.7.5 Coastal Outfall Monitoring The individual coastal jurisdictions performed and reported on the monitoring efforts. 1.2.8 2003 – 2004 Objectives and Key Elements The monitoring conducted in 2003-2004 continued the monitoring program initiated in the 2001-2002 storm season. 1.2.8.1 Water Quality Monitoring at the Mass Loading Stations Water quality monitoring at the MLS during the 2003-2004 wet-season was conducted following the methods described in Order 2001-01 and established during the 2001-2002 monitoring season. As indicated in the 2001-2002 Urban Runoff Monitoring Report, the MLS at Otay River never received any Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-13 runoff; therefore, this station was removed during the 2002-2003 monitoring program. The Navy Public Works Center continued to perform monitoring on the Santa Margarita River. The 2003-2004 MLS were: Santa Margarita River (Navy Site) San Luis Rey River Agua Hedionda Creek Escondido Creek San Dieguito River Peñasquitos Creek Tecolote Creek San Diego River Chollas Creek Sweetwater River Tijuana River All testing and analyses were similar to those performed in 2002-2003 and were conducted in accordance with applicable USEPA regulations and RWQCB guidance. 1.2.8.2 Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring The 2003-2004 monitoring season was the third year of this program, and the second year for sample collection, analysis and reporting. The program was designed to monitor the greatest potential water quality impact from urban runoff in a bay or lagoon (embayment). Based on a literature review, areas with the smallest sediment grain size and greatest TOC were most likely to reveal the water quality impacts to the receiving water. Due to spatial and temporal variability, these areas are not permanently fixed. Therefore an embayment was most effectively monitored with a two-phase sampling program. In Phase I, the embayment was stratified and sampled randomly within strata. These samples were analyzed and ranked based on grain size and TOC concentrations. In Phase II, three sites representing areas of finest grain size and highest TOC were selected and resampled. These samples were subjected to toxicological testing and chemical and biological analyses. The selected smaller suite of samples was then tested individually or as a single composite. Twelve coastal embayments were monitored. These included: Santa Margarita River Estuary Oceanside Harbor San Luis Rey River Estuary Buena Vista Lagoon Agua Hedionda Creek Batiquitos Lagoon San Elijo Lagoon San Dieguito Lagoon Los Peñasquitos Lagoon Mission Bay Sweetwater River Estuary Tijuana River Estuary 1.2.8.3 Rapid Stream Bioassessment Monitoring During the 2003-2004 monitoring season, the methods for the rapid stream bioassessment monitoring program remained the same as the previous year, with minor changes. A couple of the monitoring sites were relocated due to dry conditions. In addition, the San Diego Index of Biotic Integrity (IBI) was replaced by a more comprehensive Southern California IBI (Ode et al. 2005). The new IBI rating system covers a geographic range from southern Monterey County to the Mexican Border and inland to the eastern extent of the southern Coast Ranges. The new IBI is also tiered to account for elevation effects on benthic communities. The biological metrics used in the new IBI are different, and show a better response to watershed scale and stream reach scale disturbance gradients. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-14 1.2.8.4 Toxic Hot Spot Monitoring in San Diego Bay Toxic Hot Spot Monitoring was conducted outside of this monitoring program by the RWQCB, the Port of San Diego, and the City of San Diego in collaboration with SCCWRP and the US Navy. 1.2.8.5 Coastal Outfall Monitoring The individual coastal jurisdictions performed and reported on the monitoring efforts. 1.3 2004-2005 Scope of Work The monitoring conducted in 2004-2005 continues the monitoring program initiated in the 2001-2002 storm season. A summary of the wet-weather monitoring program stations from 1993 through 2005 is provided in Table 1-2, and the station locations are shown on Figure 1-1. 1.3.1.1 Water Quality Monitoring at the Mass Loading Stations Water quality monitoring at the MLS during the 2004-2005 wet-season was conducted following the methods described in Order 2001-01 and established during the 2001-2002 monitoring season. The Navy Public Works Center did not perform monitoring on the Santa Margarita River during the 2004- 2005 season due to sampling equipment being lost in flooding during the first rain event. The Navy indicated they would not sample during the remainder of the 2004-2005 wet-season. The 2004-2005 MLS were: San Luis Rey River Agua Hedionda Creek Escondido Creek San Dieguito River Peñasquitos Creek Tecolote Creek San Diego River Chollas Creek Sweetwater River Tijuana River All testing and analyses were similar to those performed in 2003-2004 with the exception that the analysis for Chlorpyrifos and Diazinon by ELISA methodology was discontinued. Low level Chlorpyrifos and Diazinon analysis by EPA Method 625 (GC/MS) was continued as in the previous year which allows for monitoring of additional organophosphate pesticides. All tests and analyses were conducted in accordance with applicable USEPA regulations and RWQCB guidance. Table 1-3 presents a listing of all constituents required to be analyzed and the analytical methods utilized. Table 1-4 presents a listing of additional constituents not required by the permit, but are included as part of the methodology used during the determination of Chlorpyrifos and Diazinon. For the 2004-2005 monitoring season, one toxicity identification evaluation (TIE) was performed at the Tijuana River site where toxicity was present. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-15 Table 1-2. Wet-weather monitoring stations 1993-1994 through 2004-2005. Site Name Type 1993/94 1994/95 1995/96 1996/97 1997/98 1998/99 1999/00 2000/01 2001/02 2002/03 2003/04 2004/05 NC1-Yuma Commercial z z z z z NC2-Park Residential z z z z z NC3-Yarrow Industrial z z z z z SC1-Jeremy Residential z z z z z SC2-Vernon Industrial z z z z z SC3-Walmart Commercial z z z z z SD1-Top Gun Construction z SD2-Proctor Construction z SD3-Carroll Mass loading z SD4-Rose Mass loading z SD5-Tecolote Mass loading z z z z z z z z z z z z SD6-San Diego River Mass loading z SD7-Switzer Mass loading z z z z z SD8-Chollas Mass loading z z z z z z z z z z z z SD9-Otay* Mass loading SD10-Bramson Commercial z z z z SD11-Crosby Industrial z z z z SD12-Landis Residential z z SD13-California Mass loading z z z z z SV1-Sorrento Valley Mass loading z z z z z AH1-Agua Hedionda Mass loading z z z z z z z AH-Re-Residential Bacteria z z AH-Co-Commercial Bacteria z z AH-Os-Open Space Bacteria z AH-L-Lagoon Bacteria z z AH-Lc-Lagoon Bacteria z AH-Lm-Lagoon Bacteria z AH-Rec-Residential Bacteria z AH-Coc-Commercial Bacteria z SMR-Santa Margarita River ** Mass loading z z z SLR-San Luis Rey River Mass loading z z z z EC-Escondido Creek Mass loading z z z z SDC-San Dieguito Creek Mass loading z z z z PC-Peñasquitos Creek Mass loading z z z z SDR-San Diego River Mass loading z z z z SR-Sweetwater River Mass loading z z z z OR-Otay River*** Mass loading z TJR-Tijuana River Mass loading z z z z *This station was established in the 1993/94 wet-weather monitoring season, but was vandalized before any sampling was performed. **This station was not sampled by the Navy DPW in 2004/05 due to equipment loss during the first rain event. ***This station was decommissioned at the end of the 2001/02 season. No flow was ever recorded at this site. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-16 Figure 1-1. Wet-weather monitoring stations for 1993 through 2005. Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-17 Table 1-3. Analytical requirements for Mass Loading Stations 2004-2005. Constituent Volume Required Method Reporting Limit Units Holding Time General Physical and Inorganic Non-Metals Total Dissolved Solids (TDS) 100 mL SM 2540 C 20 mg/L 7D Total Suspended Solids (TSS) 100 mL SM 2540 D 40 mg/L 7D Turbidity 100 mL SM 2130 A-B 0.1 NTU 48H Total Hardness 150 mL EPA 200.7 10 mg CaCO3/L 6M pH In field EPA 150.1 0.1 S.U. I Specific Conductance In field SM 2510 B 1.0 umhos/cm 28D Temperature In field I Dissolved Phosphorus 250 mL SM 4500 B,E 0.05 mg/L 48H Total Phosphorus 250 mL SM 4500 B,E 0.10 mg/L 28D Nitrite as N 200 mL SM 4500 NO2 B 0.05 mg/L 48H Nitrate as N 200 mL SM 4500 NO3 E 0.1 mg/L 48H Total Kjeldahl Nitrogen (TKN) 500 mL SM 4500N C 0.5 mg/L 28D Ammonia as N 250 mL SM 4500 NH3B,C 0.1 mg/L 28D Biological Oxygen Demand, 5-day (BOD) 1000 mL SM 5210 B 2 mg/L 48H Chemical Oxygen Demand (COD) 25 mL EPA 410.4 25 mg/L 28D Dissolved Organic Carbon (DOC) 200 mL EPA 415.1 1.0 mg/L Total Organic Carbon (TOC) 200 mL EPA 415.1 1.0 mg/L Methylene Blue Active Substances (MBAS) 250 mL SM 5540 C 0.5 mg/L 48H Organics Oil and Grease (O&G) 500 mL EPA 413.2 1.0 mg/L 14D Diazinon 1 L EPA 625 0.05 μg/L 14D Chlorpyrifos 1 L EPA 625 0.05 μg/L 14D Metals, Dissolved Antimony (Sb) 75 mL EPA 200.8 0.006 mg/L 6M Arsenic (As) 75 mL EPA 200.8 0.002 mg/L 6M Cadmium (Cd) 75 mL EPA 200.8 0.001 mg/L 6M Chromium (Cr) 75 mL EPA 200.8 0.005 mg/L 6M Copper (Cu) 75 mL EPA 200.8 0.010 mg/L 6M Lead (Pb) 75 mL EPA 200.8 0.005 mg/L 6M Nickel (Ni) 75 mL EPA 200.8 0.005 mg/L 6M Selenium (Se) 75 mL EPA 200.8 0.005 mg/L 6M Zinc (Zn) 75 mL EPA 200.8 0.02 mg/L 6M Metals, Total Antimony (Sb) 75 mL EPA 200.8 0.006 mg/L 6M Arsenic (As) 75 mL EPA 200.8 0.002 mg/L 6M Cadmium (Cd) 75 mL EPA 200.8 0.001 mg/L 6M Chromium (Cr) 75 mL EPA 200.8 0.005 mg/L 6M Copper (Cu) 75 mL EPA 200.8 0.010 mg/L 6M Lead (Pb) 75 mL EPA 200.8 0.005 mg/L 6M Nickel (Ni) 75 mL EPA 200.8 0.005 mg/L 6M Selenium (Se) 75 mL EPA 200.8 0.005 mg/L 6M Zinc (Zn) 75 mL EPA 200.8 0.02 mg/L 6M Bacteriological Total Coliform 200 mL SM 9221 B * MPN/100 mL 6H Fecal Coliform 200 mL SM 9221 E * MPN/100 mL 6H Enterococcus 200 mL SM 9230 * MPN/100 mL 6H Toxicity 20 L 7-day chronic test with the cladoceran Ceriodaphnia dubia Chronic test with the freshwater algae Selenastrum capricornutum Acute survival test with the amphipod Hyalella azteca. * Bacteriological methods are quantified from 20-16,000,000 MPN/100 mL Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-18 Table 1-4. Additional constituents analyzed for Mass Loading Stations 2004-2005. Constituent Volume Required Method MDL Units Holding Time Organophosphorus Pesticides Bolstar 1 L EPA 625 0.010 μg/L 14D Coumaphos 1 L EPA 625 0.010 μg/L 14D Demeton (Total) 1 L EPA 625 0.010 μg/L 14D Dichlorvos 1 L EPA 625 0.010 μg/L 14D Disulfoton 1 L EPA 625 0.010 μg/L 14D Ethoprop 1 L EPA 625 0.010 μg/L 14D Fensulfothion 1 L EPA 625 0.010 μg/L 14D Fenthion 1 L EPA 625 0.010 μg/L 14D Guthion 1 L EPA 625 0.010 μg/L 14D Malathion 1 L EPA 625 0.005 μg/L 14D Merphos 1 L EPA 625 0.010 μg/L 14D Mevinphos 1 L EPA 625 0.010 μg/L 14D Parathion, methyl 1 L EPA 625 0.010 μg/L 14D Phorate 1 L EPA 625 0.010 μg/L 14D Ronnel 1 L EPA 625 0.010 μg/L 14D Stirofos 1 L EPA 625 0.010 μg/L 14D Tokuthion 1 L EPA 625 0.010 μg/L 14D Trichloronate 1 L EPA 625 0.010 μg/L 14D 1.3.1.2 Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring The 2004-2005 monitoring season was the fourth year of this program, and the third year for sample collection, analysis, and reporting. The methods for the ambient bay, lagoon and coastal receiving water monitoring program remained the same as the previous year. Twelve coastal embayments were monitored. These included: Santa Margarita River Estuary Oceanside Harbor San Luis Rey River Estuary Buena Vista Lagoon Agua Hedionda Creek Batiquitos Lagoon San Elijo Lagoon San Dieguito Lagoon Los Peñasquitos Lagoon Rose and Tecolote Creek deltas Sweetwater River Estuary Tijuana River Estuary This report contains the results for the Phase II sampling conducted during the 2003-2004 monitoring season, and station location information and results for the Phase I sampling conducted during the 2004- 2005 monitoring season. 1.3.1.3 Rapid Stream Bioassessment Monitoring During the 2004-2005 monitoring season, the methods for the rapid stream bioassessment monitoring program remained the same as the previous year. Rapid stream bioassessment sampling occurred in October 2004 and May 2005. Rapid stream bioassessments were performed following the Southern California IBI rating system (Ode et al. 2005). Introduction SECTION 1 2004-2005 Urban Runoff Monitoring Report 1-19 1.3.1.4 Toxic Hot Spot Monitoring in San Diego Bay Toxic Hot Spot Monitoring was conducted outside of this monitoring program by the RWQCB, the Port of San Diego, and the City of San Diego in collaboration with SCCWRP and the US Navy. 1.3.1.5 Coastal Outfall Monitoring The individual coastal jurisdictions continued to perform and report on the monitoring efforts. These data were analyzed and utilized in this report during the process of conducting the watershed management area assessments. 1.4 Report Organization This report is organized to represent a watershed approach to reviewing the results. The methods for the storm water monitoring, rapid stream bioassessments, ambient bay and lagoon monitoring, and the WMA assessments are combined into a single section (Section 3). Sections 4 – 12 each represent a single WMA and results for each of the monitoring programs and watershed assessments specific to each WMA are presented together. Similar to previous years, a cross watershed comparison follows the watershed management area results. Table 1-5 provides a brief layout of this year’s report organization: Table 1-5. Report Organization. Section Description 2 Describes the study area on a regional and watershed scale. 3 Provides methods for the storm water monitoring, rapid stream bioassessment, and ambient bay and lagoon monitoring programs, and watershed management area assessments. 4 Santa Margarita River WMA results, including monitoring site descriptions, storm water monitoring (not performed at this site in 2004-2005), stream bioassessment, and ambient bay and lagoon monitoring. Results of each program are combined and an assessment of the watershed management area is presented. 5 San Luis Rey River WMA results, presented in a similar fashion as Section 4. 6 Carlsbad WMA results, presented in a similar fashion as Section 4. 7 San Dieguito River WMA results, presented in a similar fashion as Section 4. 8 Los Peñasquitos River WMA results, presented in a similar fashion as Section 4. 9 Mission Bay WMA results, presented in a similar fashion as Section 4. 10 San Diego River WMA results, presented in a similar fashion as Section 4. 11 San Diego Bay WMA results, presented in a similar fashion as Section 4. 12 Tijuana River WMA results, presented in a similar fashion as Section 4. 13 Provides a regional overview of findings and a statistical comparison of the region’s watersheds. 14 Provides conclusions and recommendations for the 2005-2006 Receiving Waters Monitoring Program. 15 References Appendix Appendices A through I Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-1 2.0 STUDY AREA DESCRIPTION 2.1 Regional Setting A summary of the general geographical setting of San Diego County including the regional topography, climate, hydrology, land use, and population is presented in this section. 2.1.1 Geomorphology San Diego County can be divided between three distinct geomorphic regions: the Coastal Plain Region as exposed west of the Peninsular Ranges, the Peninsular Range Region, and the Salton Trough Region as exposed east of the Peninsular Ranges (Figure 2-1). This geomorphic division reflects a basic geologic difference between the three regions; with Mesozoic metavolcanic, metasedimentary, and plutonic rocks predominating in the Peninsular Ranges, and Cenozoic sedimentary rocks predominating to the west and east of the central mountain range. The irregular contact between these geologic regions reflects the ancient topography of this area before it was buried by the thick sequence of Cretaceous and Tertiary sedimentary rocks deposited over the last 75 million years by ancient rivers and in ancient seas. Figure 2-1. San Diego County Geology. In the Coastal Plain region, resistant peaks composed of Mesozoic crystalline rocks extrude through the younger Cretaceous and Tertiary sedimentary cover and demonstrate the amount of topographic relief on the buried landscape of western San Diego County. The Coastal Plain Region is underlain by a sequence of marine and non-marine sedimentary rock units. Faulting has broken up this sedimentary sequence into a number of distinct fault blocks in the southwestern part of the county. North of La Jolla the effects of faulting are not as great and the rock units here are relatively undeformed. The Peninsular Ranges Region is underlain primarily by plutonic rocks that formed from the cooling of molten magmas deep within the earth’s crust. These magmas were generated during subduction of an oceanic crustal plate that was converging on the North American Plate between 140 and 90 million years ago. Over this long period of time, extensive masses of granitic rocks accumulated at depth to form the Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-2 Southern California Batholith. Intense heat associated with these plutonic magmas metamorphosed the ancient sedimentary rocks into which the plutons intruded. These metasediments are now preserved in the Peninsular Range Region as marbles, slates, schist, quartzites and gneiss. Approximately the eastern one-third of San Diego County falls within the Salton Trough Region. The Salton Trough is the northern landward extension of the Gulf of California and is undergoing active deformation related to faulting along the San Jacinto and Elsinore fault zones. These fault zones are in turn related to the major tectonic feature in the region, the San Andreas Fault. Much of the land surrounding the Salton Sea in the Imperial and Coachella valleys is below present sea level. This is the result of crustal thinning and subsidence caused by the same extensional tectonics that continue to form the Gulf of California today. As a result of this rifting and subsidence, the Salton Trough has been filled with sediments to a depth of up to five miles since the early Miocene, approximately 24 million years ago. The source of these sediments has been the local mountain ranges, as well as the ancestral and modern Colorado River (Deméré 2005). San Diego County is located within the Peninsula Range Physiographic Province of California. One of the most prominent physical features in the region is the northwest-trending Peninsula Range which includes, from north to south, the Santa Ana, Agua Tibia, Palomar, Volcan, Cuyamaca and Laguna Mountains. Generally, the region exhibits a gently sloping, dissected western surface and a steep eastern slope. The province is separated from the Salton Trough west of the Colorado River by abrupt fault scarps of marked relief (RWQCB 1994). The San Diego Region is divided into a coastal plain area, a central mountain-valley area, and an eastern mountain-valley area. The coastal plain area is a series of wave cut platforms overlain by thin terrace deposits. This terraced surface has been deeply incised by streams draining generally westward to the sea, and has been smoothed and rounded by local erosion. Local elevations range from sea level to approximately 1,500 feet. The coastal plain extends from the coast inland, along a band approximately 10 miles in width. The central mountain-valley area is characterized by ridges and intermountain basins that extend from the coastal plain, northeastward to the Elsinore fault zone. The basins or valleys range in elevation from approximately 500 to 5,000 feet, are generally of fault block origin, and have been altered by erosion. The floors of the intermountain valleys are generally underlain by moderate thicknesses of alluvium. Notable examples of this occur near El Cajon, Escondido, and Ramona where elevations range from approximately 500 to 1,500 feet above sea level. At higher elevations ranging from 2,000 to 6,000 feet near the Laguna Mountains, Santa Ysabel, and Valley Center, plateau surfaces have been developed in the central mountain-valley area. To the northeast of the Elsinore fault zone, the region has been designated as the eastern mountain- valley area. This area is comprised of broad, relatively flat valleys which are structurally of fault block origin. Locally, the down-dropped grabens contain thick sections of alluvial deposits. These valleys generally rise to the southeast from approximately 1,000 feet in elevation near Temecula to the rolling plateaus of Glenoak, Lewis, and Reed valleys which range from 3,000 to 3,500 feet in elevation. Surrounding mountains include Red Mountain, Cahuilla Mountain, and Bachelor Mountain and elevations range from 4,000 to 7,500 feet above sea level (RWQCB 1994). Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-3 2.1.2 Significant Regional Events Southern California has experienced several notable events over the past two years that are likely to impact water quality throughout the WMAs. These events include the wildfires of 2003-2004, a prolonged dry period, and the record rainfall and flooding of 2004-2005. 2.1.2.1 Wildfires Wildfires tore through large parts of San Diego County in October of 2003. A total of 600 square miles were burnt. Homes and lives were lost, wildlife habitat was devastated, air quality deteriorated, and land cover was lost. Burned areas have the potential to adversely affect water quality by increasing the nutrient load for several years to come. Additionally, the burned areas greatly increase the potential for flooding, erosion, and higher peak flows in the short term (Meixner 2004) The Cedar Fire was the largest of the 2003 burns and affected the upper portions of the Los Peñasquitos, Mission Bay, San Diego River, and San Diego Bay WMAs. Over 280,000 acres were burnt over a ten-day period. The Paradise Fire covered 57,000 acres of the San Luis Rey, Carlsbad, and San Dieguito WMAs. The Otay Fire affected 45,000 acres of the San Diego Bay and Tijuana River WMAs. The most impacted WMA was the San Diego River WMA, where 74 % (over 200,000 acres) of the watershed was impacted by the fires. The 2003 wildfires are discussed in greater detail in the 2003-2004 Urban Runoff Monitoring Report for San Diego County (MEC-Weston 2005). Wildfire activity, while not as severe as the October 2003 burns, continued in the region during the first half of 2004 when several fires broke out in the southwest portion of neighboring Riverside County. Three of these fires (Eagle, Melton, and Pleasure) totaling more than 17,000 acres in burned area, have the potential to affect WMAs of northwest San Diego County. 2.1.2.2 Large Storms and Record Rainfall October 2004 became the wettest on record for most areas, and in a few cases, broke records that stood since the 1800s. The rainfall came a day after San Diego’s Lindbergh Field set a new mark for consecutive days with no measurable rainfall at 182. The rainy period from October 17 to October 21 resulted in widespread urban and small stream flooding. Some flash flooding and mud, rock, and debris flows were reported in the burn areas. After a few days to dry out, a second storm moved through the region from October 26 through October 28. Very heavy rain and strong wind accompanied the storm, which resulted in most monitoring stations receiving precipitation well in excess of ten times the amount of a typical San Diego County storm. The San Diego River overflowed its banks for a period of time (NWS 2005a). Local urban and small stream flooding continued in November due to more showers and thunderstorms. Two- to three-inch rains were common in late December 2004 and early January 2005, resulting in the San Diego River cresting very close to flood stage. The storms caused millions of dollars of flood and storm-related damage throughout southern California. Numerous mudslides occurred throughout the region. All major river basins in southern California were impacted to some degree by the sheer volume of precipitation that fell from the combined storm periods (NWS 2005). Substantial rainfall continued throughout January and February, and into March, resulting in widespread flooding in many areas due to the saturated soils. The 2004-2005 season total precipitation for the San Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-4 Diego area was 22.49 inches, the third wettest on record and 209% of normal. This marked the first time since recordkeeping began in 1850 that four inches or more of rain has fallen in four separate months (October, December, January, and February) in a single season (NWS 2005b). 2.1.3 Rainfall and Climate The San Diego Region coastal climate is generally mild with annual average temperatures near 65°F. As elevations increase inland, average temperatures decrease to approximately 57°F in the higher mountain areas. Hot winds are predominant in the fall, resulting in the highest temperatures during the months of September and October. January is usually the coldest month of the year. The coastal portions of San Diego County receive annual average rainfall amounts ranging from less than 9 inches in the extreme southwest to 11 inches in the north. The foothills to the east of the coastal plain receive rainfall amounts ranging from 17 inches in the north to 14 inches in the south. Mountain area rainfall ranges from 45 inches at Palomar Mountain in the north, to 39 inches at Lake Cuyamaca, and 21 inches at Laguna Mountain in the south. On an annual basis, there are two distinct climatic periods: a dry (semi-arid) period from late April to mid-October, and a wet period from mid-October through late April. For the coastal and inland areas, the wet period typically provides 85 to 90 percent of the annual average rainfall, with the remaining rainfall attributed to residual storms and occasional “summer monsoons.” Rainfall during 2004-2005 was generally above historical averages. The majority of the rain fell during October, December, January, and February and was well above the average for those months (Figure 2-2). Seasonally, the 2004-2005 wet season had the most rain on record at Lindbergh Field since 1940. This was preceded by a very dry season (Figure 2-3). Rainfall statistics for the San Diego region were developed at the request of the EPA by Steuber and Nold (1986), based upon the historical data records from the National Oceanic and Atmospheric Administration (NOAA) rain gauge at San Diego International Airport’s Lindbergh Field (Table 2-1). A 39-year record from 1948 through 1986 (Table 2-1) was used to statistically analyze rainfall at this site. Results of this analysis indicated that an average of 18 storm events occur each year. The average yield of each event is 0.38 inches of rain over an approximate nine-hour period. Storm events were defined as a total accumulation of at least 0.1-inch of precipitation, together with intensities averaging at least 0.01 inches of precipitation per hour. Additionally, estimation of a representative storm event for the San Diego region was based on a statistical evaluation of this record. Based on the results of this statistical analysis, the typical storm event for the San Diego region yields 0.19 to 0.57 inches of rain and lasts 6 to 12 hours. Figure 2-3 presents a 44-year summary of annual rainfall at San Diego's Lindberg Field. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-5 MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR Mean 2004/05 0.00 1.00 2.00 3.00 4.00 5.00 6.00 Precipitation (in)Month Mean 2004/05 Source: National Weather Service 2004 Figure 2-2. San Diego - Lindbergh Field Monthly Precipitation Summary 2004-2005. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-6 0 5 10 15 20 25 196019611962196319641965196619671968196919701971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004Storm Season (Oct 1 - Apr 30)Precipitation (in) Source: National Weather Service 2005 Figure 2-3. San Diego - Lindberg Field Storm Season Rainfall 1960 to 2004. Table 2-1. Rainfall statistics for San Diego International Airport (1948 through 1986). Month Average Total (inches) Average Event Duration (hours) Average Event (inches) Average Number of Events January 2.05 11.78 0.51 3.51 February 1.96 11.10 0.43 2.94 March 1.81 10.80 0.45 3.37 April 0.75 6.31 0.23 1.77 May 0.20 2.41 0.09 0.51 June 0.07 1.07 0.08 0.19 July 0.02 0.28 0.00 0.03 August 0.07 1.07 0.08 0.19 September 0.19 2.77 0.10 0.31 October 0.42 4.31 0.18 0.78 November 1.07 8.19 0.38 2.28 December 1.74 9.29 0.37 2.53 Annual Average 10.44 9.24 0.38 18.33 Source: Steuber and Nold 1986 Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-7 2.1.4 Hydrology San Diego County has two major drainage basins; the Pacific and the Salton Sea Basin. The majority of San Diego County and all major population centers in the region are contained within the Pacific Basin (Figure 2-4). The Pacific Basin drains from the highlands in the east portion of the county to the Pacific Ocean in the west. The San Diego Region covers most of San Diego County and parts of southwestern Riverside and Orange Counties. The region is divided into nine WMAs, 11 major hydrologic units (HU), 54 hydrologic areas (HA), and 147 hydrologic subareas (HSA) (Figure 2-5 and Table 2-2). Figure 2-4. San Diego Watersheds. Source: San Diego County 2002 Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-8 Figure 2-5. San Diego Watershed Management Areas. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-9 Table 2-2. Hydrologic Areas in the San Diego Region. Watershed Management Area Hydrologic Unit HU # Hydrologic Area HA # Santa Margarita Santa Margarita 902.00 Ysidora DeLuz Murrieta Auld Pechanga Wilson Cave Rocks Aguanga Oakgrove 902.10 902.20 902.30 902.40 902.50 902.60 902.70 902.80 902.90 San Luis Rey San Luis Rey 903.00 Lower San Luis Monserate Warner Valley 903.10 903.20 903.30 Carlsbad Carlsbad 904.00 Loma Alta Buena Vista Creek Agua Hedionda Encinas San Marcos Escondido Creek 904.10 904.20 904.30 904.40 904.50 904.60 San Dieguito San Dieguito 905.00 Solana Beach Hodges San Pasqual Santa Maria Valley Santa Isabel 905.10 905.20 905.30 905.40 905.50 Peñasquitos Peñasquitos 906.00 Miramar Reservoir Poway 906.10 906.20 Mission Bay Peñasquitos 906.00 Scripps Miramar Tecolote 906.30 906.40 906.50 San Diego River San Diego 907.00 Lower San Diego San Vincente El Capitan Boulder Creek 907.10 907.20 907.30 907.40 San Diego Bay Pueblo San Diego Sweetwater Otay 908.00 909.00 910.00 Point Loma San Diego Mesa National City Lower Sweetwater Middle Sweetwater Upper Sweetwater Coronado Otay Valley Dulzura 908.10 908.20 908.30 909.10 909.20 909.30 910.10 910.20 910.30 Tijuana Tijuana 911.00 Tijuana Valley Potrero Barrett Lake Monument Morena Cottonwood Cameron Campo 911.10 911.20 911.30 911.40 911.50 911.60 911.70 911.80 Source: RWQCB 2001 Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-10 Most of the surface water streams of San Diego County are interrupted in character, having both perennial and ephemeral components. This is a result of the regional rainfall pattern and the development of surface water impoundments. Most of the major surface water streams are captured by impoundments. Many of these surface water impoundments store both natural runoff and imported water. Ground water throughout San Diego County occurs in basins that are relatively small in area and usually shallow. Nearly all of the ground water basins in the county have been intensively developed for municipal and agricultural supply purposes. Figure 2-6 illustrates the regional ground water basins and Figure 2-7 and Table 2-3 present the regional reservoirs. Source: SDCWA 2000 Figure 2-6. Major Ground Water Basins in San Diego County. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-11 Figure 2-7. San Diego Reservoirs. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-12 Table 2-3. Reservoirs in the San Diego Region. Reservoir Watershed Owner Year Built Water Source Capacity (AF) Elevation (Ft) Lake Henshaw San Luis Rey Vista Irrigation District 1923 Natural Runoff 51,774 2,656.92 Lake Wohlford Carlsbad City of Escondido 1924 Natural Runoff/ Upstream Releases 6,506 1,460.30 Dixon Carlsbad City of Escondido 1970 First Aqueduct 2,606 1,042.80 Sutherland San Dieguito City of San Diego 1953 Natural Runoff 29,685 72.90 Lake Hodges San Dieguito City of San Diego 1918 First Aqueduct/ Natural Runoff 33,550 84.58 Olivenhain San Dieguito San Diego County Water Authority 2003 Natural Runoff 24,364 989.5 San Dieguito San Dieguito San Dieguito Water District/ Santa Fe Irrigation district 1918 Second Aqueduct/ Upstream Releases 883 243.60 Lake Ramona San Dieguito Ramona Municipal Water District 1980 First Aqueduct 12,000 1,248.60 Lake Poway San Dieguito City of Poway 1971 First Aqueduct 3,330 930.80 Lake Miramar Peñasquitos City of San Diego 1960 Second Aqueduct 7,185 105.87 Lake Cuyamaca San Diego Helix Water District 1887 Natural Runoff 8,195 4,622.20 San Vincente San Diego City of San Diego 1943 First Aqueduct/ Natural Runoff/ Upstream Releases 90,230 175.38 El Capitan San Diego City of San Diego 1934 First Aqueduct/ Natural Runoff 112,807 116.58 Lake Jennings San Diego Helix Water District 1962 First Aqueduct 9,790 677.25 Lake Murray San Diego City of San Diego 1918 Second Aqueduct/ Upstream Releases 4,818 90.86 Loveland Sweetwater Sweetwater Authority 1945 Natural Runoff 25,400 1,298.36 Sweetwater Sweetwater Sweetwater Authority 1888 Natural Runoff 30,079 203.82 Lower Otay Otay City of San Diego 1919 Second Aqueduct/ Natural Runoff/ Upstream Releases 49,510 128.14 Barrett Lake Tijuana City of San Diego 1922 Natural Runoff/ Upstream Releases 37,947 104.34 Lake Morena Tijuana City of San Diego 1912 Natural Runoff 50,207 103.36 Source: SDCWA 2000 Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-13 2.1.5 Land Areas The WMA boundaries are jurisdictional group boundaries set by the RWQCB rather than natural hydrologic drainage area boundaries. In most cases, the WMA and the watershed cover the same geographic area. There are two exceptions: the Peñasquitos and Mission Bay WMAs split the Peñasquitos watershed. Figure 2-4 indicates the WMA boundaries. The San Diego Bay WMA combines the Pueblo San Diego, Sweetwater, and Otay watersheds. Table 2-4 presents the land areas for each WMA and the percentage of land that falls within San Diego County. Although, the Tijuana watershed is the largest of the San Diego area watersheds, only 27% actually lies within the San Diego region (Table 2-4 and Figure 2-8). Table 2-4. Watershed Management Areas in the San Diego Hydrologic Region. Watershed Management Area Total Acres Acres Inside San Diego Region Acres Outside San Diego Region Percent Inside San Diego Region Santa Margarita 473,971 125,777 348,194 27 San Luis Rey 359,893 359,244 649 100 Carlsbad 135,322 135,322 0 100 San Dieguito 221,307 221,307 0 100 Peñasquitos 60,418 60,418 0 100 Mission Bay 43,244 43,244 0 100 San Diego River 277,543 277,543 0 100 San Diego Bay 282,553 282,553 0 100 Tijuana 1,100,831 299,002 801,829 27 Total 3,272,614 1,901,203 1,371,411 58 Watershed areas are geographical boundaries that define a watercourse and its associated drainage basin. A single watershed can cross multiple jurisdictional boundaries. Table 2-5 presents the multi- jurisdictional composition of each watershed. Land ownership for the San Diego watersheds is primarily private. Approximately 58% of the San Diego watersheds are privately owned (Figure 2-9). Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-14 0 200,000 400,000 600,000 800,000 1,000,000 1,200,000 Tijuana RiverSanta Margarita RiverSan Luis Rey RiverSan Diego RiverSan Dieguito CreekSweetwaterCarlsbadPenasquitosOtayPueblo San DiegoacresOutside the San Diego Region Inside the San Diego Region Source: SANDAG 2000 Figure 2-8. Watershed Areas of the San Diego Hydrologic Region. 0% 20% 40% 60% 80% 100%CarlsbadOtayPenasquitosPueblo San DiegoSan DiegoSan DieguitoSan Luis ReySweetwaterPrivate Local State Federal Data source: SANDAG 2000 Figure 2-9. Land Ownership in San Diego Watersheds. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-15 Table 2-5. Watershed Acreages by Jurisdiction. Watershed Jurisdiction Acres Percent of Watershed Watershed Jurisdiction Acres Percent of Watershed Oceanside 155 0.0 El Cajon 9,245 3.3 Unincorporated 125,622 26.5 La Mesa 3,031 1.1 Riverside County 348,194 73.5 Poway 587 0.2 Santa Margarita Total 473,971 100 San Diego 46,765 16.8 Santee 10,581 3.8 Escondido 52 0.0 Unincorporated 207,334 74.7 Oceanside 15,883 4.4 San Diego Total 277,543 100 Vista 743 0.2 Unincorporated 342,566 95.2 La Mesa 1,613 4.5 Riverside County 649 0.2 Lemon Grove 1,646 4.6 San Luis Rey Total 359,893 100 National City 2,535 7.0 San Diego 30,146 83.6 Carlsbad 25,013 18.5 Unincorporated 121 0.3 Encinitas 12,396 9.2 Pueblo San Diego Total 36,061 100 Escondido 17,460 12.9 Oceanside 10,946 8.1 Chula Vista 13,406 9.1 San Marcos 15,459 11.4 La Mesa 1,136 0.8 Solana Beach 588 0.4 Lemon Grove 857 0.6 Vista 11,161 8.2 National City 2,130 1.4 Unincorporated 42,299 31.3 San Diego 2,046 1.4 Carlsbad Total 135,322 100 Unincorporated 128,463 86.8 Sweetwater Total 148,038 100 Del Mar 991 0.4 Escondido 5,659 2.6 Chula Vista 17,331 17.6 Poway 9,016 4.1 Coronado 5,105 5.2 San Diego 27,345 12.4 Imperial Beach 721 0.7 Solana Beach 1,605 0.7 National City 127 0.1 Unincorporated 176,691 79.8 San Diego 6,596 6.7 San Dieguito Total 221,307 100 Unincorporated 68,653 69.7 Otay Total 98,533 100 Del Mar 151 0.1 Poway 15,450 14.9 Imperial Beach 2,119 0.2 San Diego 86,250 83.2 San Diego 13,981 1.3 Unincorporated 1,861 1.8 Unincorporated 282,902 25.7 Peñasquitos Total 103,712 100 Mexico 801,829 72.8 Tijuana Total 1,100,831 100 Source: SANDAG 1998 2.1.6 Land Use Land use within San Diego County varies considerably from undeveloped vacant land to industrial (Table 2-6). Overall land use in the county is dominated by undeveloped vacant land and park/recreational areas. These two land uses encompass nearly 75% of the total land area in the region. Residential and agricultural land uses comprise approximately 10% and 7%, respectively. Military, transportation, communication, and utilities land uses comprise approximately 6% combined. All other land use categories, including industrial and commercial, make up the remaining 2% (SANDAG 2000). Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-16 Table 2-6. Land Use Distribution in San Diego Region (2000 Estimates). Land Use Total Acres Percentage Vacant\Underdeveloped 1,080,947 40.0% Parks and Recreation 932,706 34.5% Residential 265,233 9.8% Agriculture 192,695 7.1% Public Facilities and Utilities 160,247 5.9% Transportation 25,665 0.9% Commercial and Office 20,135 0.8% Industrial 21,265 0.8% Total 2,698,893 100% Source: SANDAG 2000 Land use within watersheds is highly variable. The San Luis Rey watershed contains the smallest amount of urban area compared with the Pueblo San Diego watershed, which contains the largest amount (Figure 2-10). Table 2-7 presents land use statistics for each of the San Diego watersheds. Land use type can affect both the amount of runoff and the constituents of concern detected in runoff. Highly urban areas usually contain more impervious surfaces that generally produce more runoff per unit of rain than undeveloped areas. As development increases, impervious surface within the watershed increases, thereby producing more runoff and a larger peak storm flow, which occurs sooner during a storm event than in undeveloped areas (TNS 2002). Table 2-8 presents planned land use statistics for vacant/undeveloped land in each of the San Diego watersheds. 0% 20% 40% 60% 80% 100%CarlsbadOtayPenasquitosPueblo San DiegoSan Diego RiverSan Dieguito CreekSan Luis Rey RiverSweetwaterVacant & Undeveloped Parks, Open Space & Agriculture Urban Source: SANDAG 2000 Figure 2-10. Land Use in San Diego Watersheds. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-17 Table 2-7. Land Use Acreage for Portions of the Watersheds in San Diego County (2000 Estimates). Watershed Total Agriculture Commercial Industrial Parks and Recreation Public Facilities/ Utilities Residential Transportation Vacant /Undeveloped Santa Margarita River 125,507 11,304 175 303 19,077 37,157 4,174 779 52,537 San Luis Rey 357,586 84,807 778 766 30,307 11,778 29,997 1,917 197,236 Carlsbad 133,661 14,100 4,165 4,671 14,197 4,129 47,774 2,242 42,382 San Dieguito River 219,559 43,110 1,019 794 29,650 1,297 29,361 1,001 113,327 Peñasquitos 101,456 2,139 3,706 5,587 21,851 6,716 31,629 3,658 26,170 Pueblo San Diego 35,908 17 2,842 1,172 3,028 4,585 19,281 2,507 2,475 San Diego River 273,196 6,590 4,221 3,880 41,492 6,375 48,163 4,430 158,046 Sweetwater River 146,590 4,630 1,735 1,265 34,946 2,974 31,892 1,939 67,210 Otay River 97,356 2,349 752 1,900 25,983 4,248 10,158 1,466 50,500 Tijuana River (US) 296,518 12,238 394 738 71,532 1,039 6,958 3,879 199,740 Grand Total 1,787,422 181,290 19,788 21,079 292,083 80,298 259,400 23,824 909,660 Source: SANDAG 2000 Table 2-8. Planned Land Use of Vacant/Undeveloped Land for Watersheds Entirely Within the San Diego Region. Developable Acres Watershed Total Vacant/ Undeveloped Constrained1 Percent Constrained Total Residential Commercial / Office Industrial Public Facilities & Utilities Parks & Recreation Agriculture Mixed Use San Luis Rey2 197,790 134,278 68 63,512 62,815 206 55 264 17 149 6 Carlsbad 43,825 18,984 43 24,840 20,959 941 1,960 562 144 0 275 San Dieguito 118,814 64,144 54 54,669 53,971 76 159 43 321 52 47 Peñasquitos 27,190 18,189 67 9,002 5,932 245 2,150 457 119 0 99 San Diego 162,084 101,723 63 60,361 59,096 294 598 208 89 0 77 Pueblo San Diego 2,115 1,674 79 441 290 31 41 26 9 0 44 Sweetwater 73,498 39,176 53 34,322 33,465 235 132 339 113 0 38 Otay 65,533 38,664 59 26,870 25,209 298 694 434 189 0 46 Total 690,849 416,832 60 274,017 261,737 2326 5,789 2,333 1,001 201 630 1 Constrained acres are areas not available for development due to physical features or local policy. 2 Total acres shown for the San Luis Rey watershed include 649 acres that fall outside the San Diego region. Source: SANDAG 2020 Forecast Planned Land Use (SANDAG 1998) Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-18 2.1.7 Population San Diego County currently has an estimated population of 2,813,833 (Table 2-9). The City of San Diego comprises a large proportion of this population with approximately 44% of the total county population living within the city limits. Unincorporated areas of the County represent another 16% of the overall population. Cumulatively, the remaining seventeen cities comprise 40% of the population although individually, each of these cities represents less than 7% of the total population in the County. Table 2-9. Population Distribution in San Diego County (Census 2000). Location Population Percentage Carlsbad 78,247 2.8% Chula Vista 173,556 6.2% Coronado 24,100 0.9% Del Mar 4,389 0.2% El Cajon 94,869 3.4% Encinitas 58,014 2.1% Escondido 133,559 4.7% Imperial Beach 26,992 1.0% La Mesa 54,749 1.9% Lemon Grove 24,918 0.9% National City 54,260 1.9% Oceanside 161,029 5.7% Poway 48,044 1.7% San Diego 1,223,400 43.5% San Marcos 54,977 2.0% Santee 52,975 1.9% Solana Beach 12,979 0.5% Vista 89,857 3.2% Unincorporated 442,919 15.7% Total 2,813,833 100% Sources: Census 2000, U.S. Census Bureau; SANDAG Residential areas tend to be concentrated along the coast, extending up to 30 miles inland in areas of favorable terrain. Inland urban expansion has resulted in the development of major transportation corridors to accommodate newer residential tracts. Strip commercial zones are common along the larger transportation corridors. Industrial centers are generally situated in areas adjoining military facilities, along transportation corridors, and on San Diego Unified Port District property. Population density within the watersheds mirrors urban development, with the San Luis Rey Watershed being the least densely populated and the Pueblo San Diego watershed being the most densely populated (Figure 2-11). Increase in population leads to increase in development, which generally leads to more impervious areas, which leads to more runoff. Table 2-10 presents the population cycle for the San Diego County watersheds. More than 55% of the area's population lives in the three most populated watersheds (Table 2-10). Water quality concerns will most likely become more of an issue in the watersheds that are projected to have significant population growth. The three least densely populated watersheds: Otay, San Dieguito, and San Luis Rey are projected to grow at the fastest rate with projected population increases of 88%, 70%, and 80%, respectively (Table 2-10). The Carlsbad, San Diego Bay, and San Diego River Watershed Management Areas stand out as having the largest populations (Figure 2-12). Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-19 SANDAG 2000 Figure 2-11. Population Per Acre for Watersheds Entirely within the San Diego Region. Table 2-10. 1990, 1997, and 2015 Population for Watersheds Entirely Within the San Diego Region. Total Population Percent Change Persons Per Acre Watershed 1990 1997 2015 1990- 1997 1997- 2015 1990- 2015 1997 2015 San Luis Rey 116,413 134,482 242,069 16 80 108 0.37 0.67 Carlsbad 426,141 472,334 706,617 11 50 66 3.49 5.22 San Dieguito 114,097 126,237 214,214 11 70 88 0.57 0.97 Peñasquitos 387,603 442,731 560,555 14 27 45 4.27 5.40 San Diego 476,304 506,420 620,542 6 23 30 1.82 2.24 Pueblo San Diego 455,238 472,204 591,162 4 25 30 13.09 16.39 Sweetwater 265,053 295,270 359,420 11 22 36 1.99 2.43 Otay 133,220 143,916 270,549 8 88 103 1.46 2.75 Total 2,374,069 2,593,594 3,565,128 9 37 50 1.36 1.88 Source: 1990 Census and SANDAG’s Population Estimates and Interim Series 8 Forecast (SANDAG 1998) Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-20 San Diego County Population Forecast derived from SANDAG 2005 demographic data estimates 0 200,000 400,000 600,000 800,000 1,000,000 1,200,000 1,400,000 Santa Margarita River San Luis Rey River Carlsbad San Dieguito River Penasquitos Mission Bay San Diego River San Diego Bay Tijuana River Watershed Management AreaPopulation20002005201020202030 Figure 2-12. Population for Watershed Management Areas Entirely Within the San Diego Region. 2.2 Monitoring Site Descriptions Monitoring site locations for the 2004-2005 MLS are shown in Figure 2-13, along with outlines of their respective runoff areas. Land use differs substantially within each catchment area and is discussed in the following sections and presented in Figures 2-14 and 2-15 (US and Mexico data included). Open land identified in the catchment area is typically covered by chaparral. The following sections summarize the major characteristics of each MLS. MLS are described in each respective WMA (Section 2.3). Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-21 Figure 2-13. Mass Loading Station Locations. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-22 0 200000 400000 600000 800000 1000000 1200000 SME SLR AHC EC SDC PC TC CC SDR SR TJRacresUnder Construction Transportation Residential Public Facility Military Industrial Indian Reservations Commercial Commercial Recreation Agriculture Parks Undeveloped Figure 2-14. Contributing Runoff Land Use Acreages by Mass Loading Station. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-23 0% 20% 40% 60% 80% 100% SME SLR AHC EC SDC PC TC CC SDR SR TJR Under Construction Transportation Public Facility Residential Military Industrial Indian Reservations Commercial Recreation Commercial Agriculture Parks Undeveloped Figure 2-15. Contributing Runoff Land Use Percentages by Mass Loading Station. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-24 2.3 Storm Event Summary 2.3.1 Representative Storm Event Estimation of a representative storm event in the San Diego region was based on the statistical evaluation of the long-term data records from the National Weather Service rain gauge located at Lindbergh Field. Based on the results of this statistical analysis, the “typical” storm event at Lindbergh Field yields 0.19 to 0.57 inches of rain and lasts 6 to 12 hours. Since the depth and duration of a typical storm event varies in different parts of the county where monitoring stations are located, storm events that were preceded by 72 hours of dry weather and were forecast to be greater than 0.10 inches were considered viable events for mobilization. A look at the 2004-2005 rain data together with the total rainfall for the year shows that representative storm events that were suitable to monitor occurred in October, January, and February. Figures 2-16 and 2-17 summarize daily rainfall totals and distributions within San Diego County. The monitored storms were preceded by at least 72 hours of dry weather. Average Daily Rainfall in San Diego County 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 10/1/200411/1/200412/1/20041/1/20052/1/20053/1/20054/1/2005Rain Figure 2-16. San Diego County Daily Rainfall Totals Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-25 Figure 2-17. San Diego County Daily Rainfall Distribution. Study Area Description SECTION 2 2004-2005 Urban Runoff Monitoring Report 2-26 2.3.2 Precipitation During Monitored Events Rainfall during the 2004-2005 wet season was well above the average of 10.44 inches (NWS 2005). Rainfall totals for each MLS are presented in Table 2-11 for each of the monitored storm events. Rainfall distributions and totals were calculated by interpolating between rainfall amounts from available National Weather Service and San Diego County rain gages for the San Diego County area and data available from rain gauges installed at the MLS. Interpolation of the rainfall over each watershed was interpolated and calculated in ArcView GIS. Table 2-11. Rainfall Summary by Mass Loading Station for Monitored Storm Events. MLS 17 Oct 04 27 Oct-04 11 Feb-05 17 Feb 05 Santa Margarita River San Luis Rey River 1.17 0.30 0.56 Agua Hedionda Creek 0.27 0.28 0.54 Escondido Creek 0.39 0.05 0.47 San Dieguito Creek 0.10 0.08 0.13 Peñasquitos Creek 0.27 0.31 0.43 Tecolote Creek 1.70 0.39 0.54 San Diego River 1.16 0.34 0.47 Chollas Creek 1.97 0.31 0.47 Sweetwater River 0.26 0.22 0.44 Tijuana River 1.61 0.86 0.51 2.3.3 Storm Water Runoff During Monitored Events The design of the storm water monitoring program is based upon the isolation of individual storm events. Storm water runoff sampling protocol requires that a flow-weighted composite sample be obtained over the duration of runoff in order to sample total flow resulting from the precipitation event. Water quality sampling was terminated based upon the end of the precipitation and cessation of storm water flow. In larger watersheds with extended periods of runoff response, it was often necessary to manually terminate the automated samplers in order to avoid sampling ground water with runoff. Hydrographs for each monitored event at the eleven mass loading stations that recorded flow are presented in Appendix A. The Navy did not submit flow data for the Santa Margarita River MLS during 2004-2005. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-1 3.0 STORM WATER MONITORING METHODS AND RESULTS 3.1 Storm Water Monitoring Methods The core monitoring program includes collection and analysis of storm water runoff at mass loading stations. Storm water was collected during three storm events at each mass loading station and analyzed for chemical constituents, indicator bacteria, and toxicity to bioassay test organisms. This section describes storm water monitoring methodology. 3.1.1 Mass Loading Station (MLS) Site Selection The 2004-2005 storm water monitoring program included eleven mass loading monitoring stations. The mass loading stations monitor large drainage areas with mixed land use characteristics. Their locations are shown in Figure 2-13. In 2000, the mass loading monitoring site locations were selected by Weston, working with the San Diego Copermittees’ Monitoring Workgroup, and approved by the San Diego RWQCB. The primary site selection factors included: ● Suitability of the site drainage area to monitor area-wide contributions of storm water pollutant loading; ● Suitability of the site’s hydrological characteristics to enable practical measurement of flow and collection of representative storm water samples; ● Maintenance of long-term data collection at appropriate existing monitoring stations (Agua Hedionda Creek, Tecolote Creek, and Chollas Creek); ● Safety from traffic and other hazards; ● Suitable siting for sampling equipment; ● Accessibility to phone lines (convenient, though not necessary for modem communications); and ● Crew access for retrieving samples and maintaining equipment during storm conditions. The mass loading sites were selected to directly measure pollutant loads being discharged into San Diego’s receiving waters by the major watersheds within the San Diego region. Monitoring sites were installed where flow from the catchment area passes a single hydrologically ratable point, and is suitable for measurements and sampling. In some instances, sites were located upstream of the drainage area discharge point for accessibility and/or to avoid tidal influences. 3.1.2 Monitoring Equipment Flow was monitored at all stations using American Sigma flow meters. A variety of flow measurement technologies were utilized to accurately measure flow rates including ultrasonic sensors, bubblers, and submerged pressure transducers. The sensors provided a continuous measurement of river or stream stage (height) and relayed that information to the flow meter. The flow meter continually calculated flow rates by inserting the stage information into the preprogrammed discharge equation. Two stations are co-located with U.S. Geological Survey (USGS) stream gauging stations. At these sites the USGS rating curves were used. Field crews measured the flow rate of streams using USGS stream profiling guidelines prior to the beginning of the storm season, and periodically throughout the storm season. This was accomplished by manual rating techniques using a hand held flow meter. The resulting discharge rates were used to calculate a discharge equation, which was utilized by the flow monitoring equipment at some stations. At Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-2 other stations where a discharge equation could not be developed, velocity/stage measurements were utilized to calculate discharge rates using the area velocity method. 3.1.3 Sampling Procedures 3.1.3.1 Grab Samples Grab samples were collected for those constituents that are not amenable to composite sampling. The grab samples were analyzed for the following parameters: Temperature pH Specific Conductance Biochemical Oxygen Demand Oil and grease Total coliform Fecal coliform Enterococcus Samples were collected from the horizontal and vertical center of the channel if possible and kept clear from uncharacteristic floating debris. Because oil and grease and other petroleum hydrocarbons tend to float, oil and grease grab samples were collected at the air/water interface. Bacteria samples were collected in a sterile sample bottle and then placed in a clean Ziploc bag and put on ice for transport to the laboratory for analysis within 6 hours. 3.1.3.2 Composite Samples Storm water samples were flow-weighted composites of the storm event. Where practical, the entire event was sampled. At some monitoring stations this was not practical due to the runoff characteristics of the watershed. For example, San Luis Rey and San Diego Rivers are large water bodies that continue to rise following the initial flow of runoff during storm events and it is not uncommon to see a double peak in the hydrographs. The first peak (usually smaller than the second) is the immediate response from runoff. The second peak is the result of groundwater flowing from the unsaturated zone that appears as a much larger peak, usually hours or days after rainfall has stopped. Sampling this flow would dilute the constituents of concern in the composite sample and may skew results when compared with other watersheds that see only immediate runoff response. For large watersheds, the sampling strategy was determined by using best professional judgment to monitor rainfall and runoff and determine the appropriate time to terminate sampling. In general, a larger concentration of pollutants from urban runoff enters the storm drainage system during the initial stages of flow and during peak flow and/or peak rainfall intensity for small rainfall events, which are typical in our region (Tiefenthaler et al. 2001; City of Austin 1990). Therefore a successful event was determined by capturing (at a minimum) the initial peak of runoff from the storm event. Storm teams evaluated telemetry data from the monitoring sites during storms to ensure all of these conditions were met before terminating sampling. Storm hydrographs for each of the monitored events are presented in Appendix A. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-3 Stream rating on Peñasquitos Creek 3.1.4 Stream Rating Methods During storms, the flow rate at each of the monitoring sites was determined by water velocity and stream stage (water level) sensors that are typically secured to the bottom of the channel. However, to better quantify flow rates and produce a more complete rating curve, each of the streams was also assessed using the classical stream rating method developed by the USGS. The materials used for the stream rating included a Marsh- McBirney Model 2000 Portable Flow Meter connected via a cable to an electromagnetic open channel velocity sensor. The sensor is attached to a stainless steel top-setting wading rod. To make a flow measurement, a tape measure was stretched across the stream, perpendicular to flow and secured on both banks of the stream. The tape was positioned so that it was suspended approximately one foot above the surface of the water. The distance on the tape directly above the waterline (where the water met the bank) was then recorded as the initial point. Generally, depth and flow were both zero at this point unless the bank was very steep. The first measurement was then made at the first point where there was adequate depth (at least 0.2 feet) and measurable velocity. At this point three measurements were made: water depth, velocity, and distance from the bank (the initial point). Subsequent depth, velocity, and distance measurements were then made incrementally across the entire width of the channel so that a minimum of ten points were measured per site. Water depth was determined from calibrations on the wading rod in tenths of feet. Velocity measurements were made at each point along the transect by positioning the velocity sensor perpendicular to flow at 60% of the water depth (from the surface) to attain an average velocity. The top setting wading rod is designed so that the sensor can be conveniently positioned at the appropriate depth. Water velocity was measured in feet per second. Data from the field measurements were entered into a computer model that calculates the stream’s cross-sectional profile from the depth and distance from bank measurements. Total flow across the channel was determined by integrating the velocity measurements over the cross-sectional surface area of the stream channel. The result is an instantaneous flow measurement in cubic feet per second. Several stream ratings were measured for each of the streams where flow was measurable after a storm and combined to produce a rating curve for each stream. Information from the rating curve was used to more accurately predict expected flow rates and appropriate sampling frequencies during storms. 3.1.5 Sample Handling and Processing In accordance with USEPA sampling protocols and the Weston Quality Assurance Program, all samples collected were stored in the appropriate container type for the analytical method to be performed. Additionally, all samples were stored chilled in ice-chests for transfer to the laboratory and between laboratories. The sample containers used were certified as clean and sterile by the laboratory performing the analyses. Chain-of-custody forms were completed for each sample and accompanied the samples to the laboratories and between laboratories at all times. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-4 Sample preservatives and holding time requirements for each analytical measurement (Table 3-1) were as recommended by the Standard Methods for Examination of Waters and Wastewaters and the USEPA methods. All storm water samples were transported from the field to the laboratory under Weston chain-of-custody procedures. Samples moved between laboratories were transported under the laboratories’ chain-of-custody procedures. Samples were submitted by Weston to EnviroMatrix Analytical, Inc. in San Diego and CRG Marine Laboratories in Torrance. 3.1.6 Laboratory Analysis 3.1.6.1 Chemical Constituents General physical and chemical constituents were analyzed by EnviroMatrix Analytical, Inc. with the exception of field measured constituents (pH, conductivity, and temperature) and the organophosphate pesticides Diazinon and Chlorpyrifos. The field measurements were made by Weston field technicians and scientists during field sampling activities. EPA 625 was utilized to test for Diazinon and Chlorpyrifos during the 2004-2005 monitoring season. During the 2003-2004 monitoring season the chemistry laboratory was not able to consistently meet the low reporting limit requirements using EPA 8141 and the ELISA data was utilized for organophosphate pesticides. Based upon the 2002-2003 results, the 625 method was added to provide a means of consistently meeting the low reporting limit requirements. The ELISA method was not utilized during the 2004-2005 monitoring season. CRG Marine Laboratories provided laboratory services for the analysis of Diazinon and Chlorpyrifos using the EPA 625 Method. CRG was able to consistently meet the low detection limits. The following table (Table 3-1) lists chemical constituents measured in this monitoring program. 3.1.6.2 Toxicity Testing Toxicity testing is an effective tool for assessing the potential impact of complex mixtures of unknown pollutants on aquatic life in receiving waters. Rather than performing chemical analysis on a sample for a host of compounds potentially toxic to aquatic life, this approach utilizes a laboratory test species to provide a direct measure of the toxicity of the sample. Interactions among the complex mixture of chemicals and physical constituents can lead to additive or antagonistic effects, potentially causing an individual compound to become either more or less toxic than it would be were it isolated. While the potential effects of these interactions cannot be derived from simple chemical measurements, they are directly accounted for in toxicity tests. If persistent toxicity is detected, specialized toxicity identification evaluations (TIE) may be used to help characterize and identify constituent(s) causing toxicity. Toxicity testing can provide information on both potential short-term or “acute” effects as well as longer-term “chronic” effects. Historically, toxicity tests, including TIEs, have been used to assess both short and long term impacts of point source discharges (e.g., Publicly Owned Treatment Works (POTW), power plant and industrial effluents) on aquatic life in a receiving water body. However, these tools can be applied to non-point source discharges, such as urban runoff. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-5 Table 3-1. Analytical requirements for mass loading stations. Constituent Volume Required Method Reporting Limit Units Holding Time Conventionals, Nutrients, Hydrocarbons Total Dissolved Solids (TDS) 100 mL SM 2540C 20 mg/L 7D Total Suspended Solids (TSS) 100 mL SM2540D 20 mg/L 7D Turbidity 100 mL SM 2130A-B 0.05 NTU 48H Total Hardness 150 mL SM 2340B 10 mg/L 6M pH In field EPA 150.1 0.1 S.U. I Specific Conductance In field SM 2510B 1 umhos/cm 28D Temperature In field I Dissolved Phosphorus 250 mL SM 4500PE 0.05 mg/L 48H Total Phosphorus 250 mL SM 4500PE 0.05 mg/L 28D Nitrite 200 mL SM 4500NO2B 0.05 mg/L 48H Nitrate 200 mL SM 4500NO3E 0.1 mg/L 48H Total Kjeldahl Nitrogen (TKN) 500 mL SM 4500C 0.05 mg/L 28D Ammonia 250 mL SM 4500NH3D 0.1 mg/L 28D Biological Oxygen Demand, 5-day (BOD) 1000 mL SM5210B 2 mg/L 48H Chemical Oxygen Demand (COD) 25 mL EPA 410.4 25 mg/L 28D Total Organic Carbon (TOC) 125 mL SM5310 B 1 mg/L 28D Dissolved Organic Carbon (DOC) 125 mL SM5310 B 1 mg/L 28D Methylene Blue Active Substances (MBAS) 250 mL SM 5540C 0.5 mg/L 48H Oil and Grease (O&G) 500 mL EPA 413.2 1 mg/L 14D Pesticides Diazinon 1 liter EPA 625 0.05 μg/L 14D Chlorpyrifos 1 liter EPA 625 0.05 μg/L 14D Malathion 1 liter EPA 625 0.05 μg/L 14D Metals, Total & Dissolved Antimony (Sb) 75 mL EPA 200.8 0.002 mg/L 6M Arsenic (As) 75 mL EPA 200.8 0.001 mg/L 6M Cadmium (Cd) 75 mL EPA 200.8 0.001 mg/L 6M Chromium (Cr) 75 mL EPA 200.8 0.005 mg/L 6M Copper (Cu) 75 mL EPA 200.8 0.005 mg/L 6M Lead (Pb) 75 mL EPA 200.8 0.002 mg/L 6M Nickel (Ni) 75 mL EPA 200.8 0.002 mg/L 6M Selenium (Se) 75 mL EPA 200.8 0.004 mg/L 6M Zinc (Zn) 75 mL EPA 200.8 0.02 mg/L 6M Bacteriological Total Coliform 200 mL SM 9221B 20 MPN/100 mL 6H Fecal Coliform 200 mL SM9221E 20 MPN/100 mL 6H Enterococcus 200 mL SM 9230 10 MPN/100 mL 6H Toxicity 20 L * *7-day chronic test with the cladoceran Ceriodaphnia dubia *Chronic test with the freshwater algae Selenastrum capricornutum *Acute survival test with the amphipod Hyalella azteca. See Section 1, Table 1-4 for additional constituents monitored. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-6 Toxicity testing provides the only direct means to assess the potential toxicity of storm water runoff on receiving waters. Living organisms are able to integrate effects of multiple contaminants and account for the inherent properties of the sample matrix (e.g., hardness and alkalinity of a storm water sample) that influence bioavailability and hence toxicity. However, the same elements that make these tools so effective can contribute to variability in the response. Living organisms respond to a host of factors other than contaminants. If animals are stressed in any way prior to testing, variability of the test organism response may increase and produce equivocal results. The use of controls and reference toxicant testing are quality assurance and quality control measures that have been put in place to identify changes in test organism sensitivity due to stress or other factors. Naturally occurring characteristics of the sample matrix can also affect organism response. For example, mortality of test organisms can result from extreme variations in water hardness. Consequently, understanding the importance of such features on test organism response is critical for the accurate interpretation of test results. The test procedures employed to date represent the culmination of some 40 years of research. While this does not guarantee that they are employed properly in every circumstance, there is a wealth of information to document the utility of such procedures. Freshwater species were used to evaluate the potential impacts of storm water at mass loading stations. These included the Santa Margarita River, San Diego River, Chollas Creek, Tecolote Creek, Escondido Creek, Los Peñasquitos Creek, San Luis Rey River, Sweetwater River, Tijuana River, Agua Hedionda Creek, and San Dieguito River. It is important to note that, ultimately, all of the receiving water bodies for these drainage basins are estuarine/marine (e.g., San Diego Bay, Mission Bay, various coastal lagoons and estuaries). The extrapolation of these freshwater species tests to evaluate the potential impact in the downstream marine/estuarine environments can be problematic. For example, the organic ligands present in an estuarine environment may make contaminants unavailable for uptake and reduce toxicity. In addition, marine organisms often have different sensitivities to contaminants than freshwater organisms. The core monitoring program includes ambient bay and lagoon monitoring to assess long term impacts to marine/estuarine receiving waters. Three species were used in this monitoring program. The cladoceran, Ceriodaphnia dubia, represents the invertebrates that live in the water column and serve as a source of food for larger invertebrates and small fish. This species is known to be sensitive to metals and pesticides in water, as well as other contaminants. The freshwater amphipod, Hyalella azteca, is an invertebrate that is associated with the sediment at the bottom of streams and lakes. It again serves as a food source for larger invertebrates as well as fish. This species is generally sensitive to metals and pesticides, as well as nitrogen compounds such as ammonia. The freshwater plant, Selenastrum capricornutum, is a unicellular algae that is present in the water column of lakes and streams. It is at the base of the food chain in freshwater systems. It is sensitive to herbicides and metals, but its growth is also greatly affected by nutrient loads (e.g., nitrates and phosphorus) in a water body. Nutrients tend to stimulate the growth of S. capricornutum (causing an algal bloom) and, if the nutrient loads are high enough in a water body, they can offset the toxic effect that contaminants might otherwise produce. The majority of the toxicity tests were conducted by Weston’s laboratory in Carlsbad, California. However, some of the Ceriodaphnia dubia tests were sent to ENSR International in Fort Collins, Colorado, and to ENERGY LABORATORIES, INC in Billings, Montana. Ceriodaphnia dubia Samples from mass loading stations were tested for toxicity according to the USEPA protocol (EPA-821- R-02-013). This protocol was developed for testing the chronic toxicity of point-source discharges where the effluent is diluted considerably in the receiving waters. Laboratory test organisms are placed Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-7 in small containers of effluent sample and monitored over time to compare the response of organisms placed in non-toxic control water to the sample water. The sample is diluted (with control water) to several known concentrations before the test and test organisms are added to each concentration. The standard USEPA recommended dilution series (100%, 50%, 25%, 12.5%, 6.25%, and a control) are used for all toxicity tests. The test solutions are renewed and animals are fed daily. In the Ceriodaphnia chronic test, single females are placed in individual test chambers (ten test chambers per concentration) and the number of dead organisms along with the number of offspring produced per organism is recorded each day. When the controls reach an average of at least fifteen young per surviving adult, and 60% of the controls have had three broods, the test is terminated (day six to eight). Additionally, the acute, 96-hour (4-day) endpoint data (survival) is also collected from the seven-day chronic test. Only the original test organisms with which the test was begun were used for the calculation of both the acute and chronic survival endpoints. Test Acceptability Acceptability of the test is determined by evaluating the response of the control organisms. The test is considered acceptable if control survival is greater than 80%, control reproduction is greater than or equal to an average of fifteen young per adult, and more than 60% of the adults produce three broods by day eight of the test. If any one of these test acceptability standards is not met then the test is considered invalid and no further analysis is performed. A reference toxicant test is also run to establish whether the test organisms used fall within the normal range of sensitivity. The reference toxicant test is conducted with known concentrations of a given toxicant (e.g., copper sulfate is used for Ceriodaphnia). The effect on the survival and reproduction of the animals is compared to historical laboratory data for the test species and reference toxicant. If the values are within two standard deviations of the historical average, the test organisms are considered to fall within the normal range of sensitivity. The concentration that causes 50% mortality of the organisms (the median lethal concentration, or LC50) is calculated from the data for 96 hours (96-hour acute LC50) and for day seven (seven-day chronic LC50) using USEPA methods. The LC50 values are point-estimates expressed as “percent sample;” the lower the LC50 percentage the more toxic the sample. For acute regulatory standards, the LC50 acute value is used. For chronic regulatory standards, the NOEC, or No Observed Effect Concentration, for both survival and reproduction is calculated. This is the highest concentration tested in which there was no statistically significant effect on the survival or reproduction compared to the control response. The lower the NOEC, the more toxic the sample. For regulatory purposes, the endpoints described above are transformed into toxic units (TU). Toxic units are further divided into toxic units acute (TUa) and toxic units chronic (TUc) for acute and chronic endpoints, respectively. As toxicity increases, the toxic units increase. If the TU limit in the permit is exceeded, the sample is out of compliance (similar to an exceedance of a chemistry limit). The permit limit for chronic toxicity is a TUc of 1 and the permit limit for acute toxicity is a TUa of 0 due to the differences in their derivation. TUa and TUc values are calculated very differently and are not interchangeable or related. The TUa equals 100/LC50. If the LC50 is greater than 100%, then the TUa is calculated by the following formula: TUa = log(100-S)/1.7 where S = percentage of survival in 100% sample. If S > 99%, the TUa is reported as zero, which is the lowest TUa value possible. The percent survival in the 100% concentration used in this formula is expressed as a percentage of the control survival. The TUc equals Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-8 100/NOEC. The lowest TUc possible, which indicates no toxicity, is 1. TUc values were calculated separately for survival and reproduction endpoints. Due to unhealthy Ceriodaphnia dubia cultures, the Bioassay Laboratory at Weston was not able to conduct the Ceriodaphnia dubia toxicity tests for two storm events during the 2004-2005 monitoring year. These samples were sent to ENSR International in Fort Collins, Colorado and to ENERGY LABORATORIES, INC in Billings, Montana for analysis. Hyalella azteca Storm water samples from each of the mass loading stations were also evaluated for acute toxicity using the freshwater amphipod, Hyalella azteca, according to a modified version of the USEPA protocol for testing sediment-associated contaminants with freshwater invertebrates (EPA-821-R-02-012). This protocol provides test methods for measuring acute toxicity in Hyalella exposed to freshwater sediments, as well as a test method for conducting a water-only acute reference toxicant test. The reference toxicant test protocol was modified to conduct the toxicity testing on samples collected from the mass loading stations. The test solution is prepared using the dilution series described above, and placed in 250-mL aliquots into 4 replicate test chambers. Clean sand is placed as a thin “monolayer” in the bottom of the test chamber and 10 organisms per replicate are added. The animals are exposed for four days and fed on day 2. At the end of the test, the survivors are removed from the sand and counted. A 96- hour LC50 is calculated from this data. Prior to analysis of the data, test acceptability is determined by evaluating the response of the control organisms. The test is considered invalid if survival of control animals is less than 90%. As with Ceriodaphnia, a reference toxicant test using copper sulfate is also conducted with Hyalella to establish whether the test organisms used fall within the normal range of sensitivity. If the test data meet acceptability criteria, the LC50 is calculated from the 96-hour test data. From this data, a toxic unit acute (TUa) is calculated as described above. Selenastrum capricornutum* In previous years, toxicity testing for the storm water monitoring program was conducted using a freshwater vertebrate species: the fathead minnow (Pimephales promelas). Results of tests conducted with this species failed to show any toxicity relative to the other species tested. Consequently, the San Diego Regional Water Quality Control Board (RWQCB) approved the replacement of this test with a chronic Hyalella toxicity test measuring a sublethal endpoint (e.g., growth). Attempts to develop a short- term sublethal toxicity test with Hyalella during the 1999-2000 and 2000-2001 storm seasons proved unsuccessful, due to the variability of the growth endpoint. Consequently, it was recommended and the RWQCB subsequently approved replacing the proposed Hyalella chronic test with the Selenastrum capricornutum chronic test. This algal species has the potential to be sensitive to metals (in waters low in nutrients) and herbicides. This is the fourth season that this test has been used to assess toxicity in this storm water monitoring program. Samples from the mass loading stations were tested for toxicity according to the USEPA protocol (EPA- 821-R-02-013) using the unicellular algae Selenastrum. This protocol was developed for testing the 96- hour chronic toxicity of point-source discharges. The sample and the control water are spiked with equal amounts of nutrients and subsequently filtered to remove any unicellular algae that might be present prior to test initiation. The concentration series is prepared and 50-mL aliquots are placed into four replicate test chambers. Approximately 10,000 cells per mL are added to the test chamber and placed in random order under high-intensity 24-hour light for four days. The test chambers are shaken twice and Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-9 randomized daily. At the end of the test period, chambers are analyzed for chlorophyll a concentrations (fluorescence). Test acceptability is determined by evaluating the response of the control organisms. The test is considered invalid if the criterion of a mean cell density of 1,000,000 cells per mL in the control is not met. Variability between the control replicates should not exceed 20%. A reference toxicant test using copper sulfate is also run parallel with the test to establish the sensitivity of the organisms. Alterations to the S. capricornutum testing protocol were put into effect with the promulgation of the updated EPA guidelines in October 2002. The most significant changes to the protocol involve the addition of ethylenediaminetetraacetic acid (EDTA) as a component of the nutrient stock for conducting the test. The addition of EDTA has been determined to greatly reduce the incidences of false positives and increase the precision of the test method. This chemical has the ability of reducing the toxicity of certain metals by making them unavailable to the test organism. The guidance document warns that this method may underestimate the toxicity of metals and should be used in conjunction with multiple species tests, such as in this program, to monitor toxicity. Another alteration to test protocol was increasing the acceptability criterion of a mean cell density 200,000 algal cells per mL in the control to 1,000,000 cells per mL. If the test data meet acceptability criteria, inhibition concentrations, an IC25 and an IC50, are calculated from the data: the concentrations that cause a 25% or 50% inhibition in the growth, or cell density, of the algae. A NOEC is also calculated from this data and the endpoint is recorded as a TUc, similar to the Ceriodaphnia test. *The name of this species has been changed to Pseudokirchneriella subcapitata, however, Selenastrum capricornutum will continue to be utilized for the purposes of continuity with previous testing. 3.1.6.3 Microbiology Testing Measures of bacteria from grab samples were made by the Weston microbiology laboratory located in Carlsbad, California. Samples were collected during the storm event using grab poles and aseptic techniques by Weston field technicians and scientists and delivered to the microbiology laboratory within the six hour holding time requirement. Sample analyses were initiated immediately upon receipt for all three indicators by multiple tube fermentation; total coliform using SM 9221B, fecal coliform using SM 9221E, and enterococcus using SM 9230B. All results were reported to a most probable number value (MPN/100mL) with no “greater than” values reported. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-10 3.2 Rapid Stream Bioassessment Methods Weston conducted stream bioassessment pursuant to RWQCB Order No. 2001-01 to assess the ecological health of the watershed units in San Diego County. The assessment was undertaken utilizing a protocol that samples and analyzes populations of benthic macroinvertebrates (BMIs). This program supplements the monitoring program conducted by the California Department of Fish and Game (CDFG) Water Pollution Control Laboratory from 1997 to May of 2001, under contract to the RWQCB. Weston followed the sampling and analysis protocols of the California Stream Bioassessment Procedure (CSBP) (Harrington 1999), a standardized procedure developed for California by CDFG and adapted from the U.S. Environmental Protection Agency (EPA) Rapid Bioassessment Protocols (Barbour et al. 1999). To further enhance data consistency and comparability, Weston sampled many of the same streams at similar locations as the previous CDFG surveys. CDFG selected the original sampling sites to complement the RWQCB’s ongoing water quality monitoring programs. The sampling protocol of the CSBP includes the collection of stream benthic macroinvertebrates and also assesses the quality and condition of the physical habitat. Utilizing species specific tolerance values and community species composition, numerical biometric indices are calculated, allowing for comparison of relative habitat health among streams in a region. Over time, this information is used to identify ecological trends and aid analyses of the appropriateness of water quality management programs (Yoder and Rankin 1998). Invertebrates reside in streams for periods ranging from a month to several years, and have varying sensitivities to the multiple stressors associated with urban runoff. By assessing the invertebrate community structure of a stream, a cumulative measure of stream habitat health and ecological response is obtained. This information may complement monitoring programs that test the chemical and physical water quality parameters and provide a measure of habitat conditions at the moment sampling occurs. The addition of bioassessment to chemical, bacterial, and toxicological approaches to watershed monitoring programs gives a comprehensive indication of water quality and the effects of ecological impacts. This report presents the results from stream bioassessment surveys conducted in October 2004 and May 2005. The data includes a taxonomic listing of all benthic macroinvertebrates identified in the surveys, and calculation of the biological metrics listed in the CSBP. Additionally, calculation of the Index of Biotic Integrity (IBI) for all monitoring reaches is included, following the most recent version developed by the CDFG Aquatic Bioassessment Laboratory specifically for coastal Southern California (Ode et al. 2005). Benthic macroinvertebrate sampling Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-11 3.2.1 Materials and Methods A general description of the methods incorporated in the sampling program is presented below. Weston personnel adhered to the protocols of the CSBP (Harrington 1999) as closely as practicable, and this document may be referenced for more detailed procedural information. 3.2.2 Monitoring Reaches A minimum of 23 monitoring reaches were sampled in each survey, including three reference sites per survey. Descriptions of the locations are presented in Table 3-2 and a map illustrating these locations is shown in Figure 3-1. The primary goal for each survey was to sample 2 monitoring reaches in each of the 10 watershed management areas that have storm water mass loading stations. Of the two monitoring reaches, one was located as far downstream in the watershed as was practicable, and the other was located farther upstream in the watershed, but where it was still affected to some degree by urban development. Where possible, sites were located in the same stream reach that CDFG has previously sampled. Ongoing reconnaissance of the streams, with the goal of finding riffles with the highest quality in-stream habitats, has resulted in re-location of some of the monitoring reaches since the beginning of the program. Reference sites have been designated by CDFG and the RWQCB based on upstream land use characteristics as determined by GIS datasets. When selecting reference monitoring sites for comparison with urban affected sites, elevation was considered, and most of the reference sites were at similar elevation to the urban sites. It may be noted that the physical habitat quality at the reference sites was superior to some of the test monitoring sites. Table 3-2. San Diego County: Stream Bioassessment Monitoring Sites. June 2001 to May 2005. Watershed Name Receiving Water Station Identification Site Description Station Coordinates Jun-01 Oct-01 May-02 Oct-02 May-03 Oct-03 May-04 Oct-04 May-05 Reference Sites Santa Margarita River Sandia Creek REF-SC Reach consisted of 5 riffles along Sandia Creek Drive 33 25.482' 117 14.942' x x x x x x Santa Margarita River Sandia Creek REF-SC2 Reach consisted of 5 riffles along De Luz Road 33 29.529' 117 16.020' x x x Santa Margarita River Sandia Creek REF-SCCR Reach consisted of 5 riffles downstream of Carancho Road 33 29.529' 117 16.020' x Santa Margarita River San Mateo Creek REF-SMC Reach consisted of 3 riffles upstream of San Mateo Road 33 25.248' 117 32.000' x Santa Margarita River De Luz Creek REF-DLC Reach consisted of 5 riffles downstream of De Luz Road 33 26.483' 117 19.434' x x x x x Santa Margarita River De Luz Creek REF-DLC3 Reach consisted of 5 riffles along De Luz-Murietta Road 33 27.574' 117 17.456' x x x San Luis Rey River Doane Creek REF-DC Reach consisted of 5 riffles upstream of Doane Pond in Palomar Mt. State Park 33 20.124' 116 53.496' x x x San Luis Rey River Keys Creek REF-KC Reach consisted of 5 riffles at Old Lilac Road 33 17.744' 117 05.149' x x x Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-12 Table 3-2. San Diego County: Stream Bioassessment Monitoring Sites. June 2001 to May 2005. Watershed Name Receiving Water Station Identification Site Description Station Coordinates Jun-01 Oct-01 May-02 Oct-02 May-03 Oct-03 May-04 Oct-04 May-05 San Diego River Cedar Creek REF-CC Reach consisted of 5 riffles upstream of Cedar Creek Road 33 01.154' 116 38.029' x Tijuana River Wilson Creek REF-WC Reach consisted of 5 riffles upstream of Lyons Valley Road 32 42.449' 116 44.231' x Urban Influenced Sites Santa Margarita River Santa Margarita River SMR-WGR Reach consisted of 5 riffles upstream of Willow Glen Road 33 25.614' 117 11.861' x x x x x x Santa Margarita River Santa Margarita River SMR-DLR Reach consisted of 5 riffles downstream of De Luz Road 33 23.844' 117 15.734' x Santa Margarita River Santa Margarita River SMR-CP Reach consisted of 5 riffles downstream of Santa Margarita Road, Camp Pendleton 33 20.457' 117 19.897' x x x x x San Luis Rey River San Luis Rey River SLRR-BR Reach consisted of 2 riffles near the USGS gauging station at Benet Road 33 13.095' 117 21.569' x x x x x x x San Luis Rey River San Luis Rey River SLRR-MR Reach consisted of 3 riffles upstream of Mission Road 33 15.587' 117 14.176' x x x x x x x x x Carlsbad Loma Alta Creek LAC-ECR Reach consisted of 3 riffles up and downstream of El Camino Real 33 11.995' 117 19.878' x x x x Carlsbad Loma Alta Creek LAC-CB Reach consisted of 5 riffles of College Blvd. 33 12.363' 117 17.087' x x x Carlsbad Buena Vista Creek BVR-ED Reach consisted of 5 riffles downstream of Santa Fe Av. 33 10.840' 117 19.717' x x x Carlsbad Buena Vista Creek BVR-CB Reach consisted of 5 riffles downstream of College Blvd. 33 10.809' 117 17.918' x x x x Carlsbad Buena Vista Creek BVR-SVW Reach consisted of 5 riffles downstream of South Vista Way. 33 10.840' 117 19.713' x Carlsbad Agua Hedionda Creek AHC-MR Reach consisted of 5 riffles downstream of Melrose Road 33 09.132' 117 14.454' x x x x x x x x x Carlsbad Agua Hedionda Creek AHC-ECR Reach consisted of 5 riffles downstream of El Camino Real 33 08.940' 117 17.830' x x x x x x x x x Carlsbad San Marcos Creek SMC-M Reach consisted of 5 riffles upstream of McMahr Road 33 07.831' 117 11.575' x x x Carlsbad San Marcos Creek SMC-SP Reach consisted of 5 riffles downstream of Santar Place 33 08.501' 117 08.740' x x x Carlsbad San Marcos Creek SMC-RSFR Rreach consisted of 4 riffles downstream of Rancho Santa Fe Road 33 06.191' 117 13.609' x x x Carlsbad San Marcos Creek SMC-LCCC Reach consisted of 5 riffles upstream of La Costa Country Club 33 05.466' 117 14.664' x x x x x Carlsbad Encinitas Creek ENC-GVR Reach consisted of 3 riffles southwest of El Camino Real and La Costa Blvd 33 04.697' 117 16.000' x x x Carlsbad Cottonwood Creek CC-E Reach consisted of 4 riffles downstream of Hwy 101 along Encinitas Blvd. 33 02.905' 117 17.629' x x x Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-13 Table 3-2. San Diego County: Stream Bioassessment Monitoring Sites. June 2001 to May 2005. Watershed Name Receiving Water Station Identification Site Description Station Coordinates Jun-01 Oct-01 May-02 Oct-02 May-03 Oct-03 May-04 Oct-04 May-05 Escondido Creek Escondido Creek ESC-HRB Reach consisted of 5 riffles downstream of Harmony Grove Bridge 33 06.550' 117 06.688' x x x x x x x x x Escondido Creek Escondido Creek ESC-CC Reach consisted of 5 riffles downstream of Country Club Road 33 05.925' 117 07.836' x Escondido Creek Escondido Creek ESC-EF Reach consisted of 5 riffles downstream of the old Elfin Forest Resort 33 04.417' 117 09.853' x x x x x x x x x Escondido Creek Escondido Creek ESC-VC Reach consisted of 5 riffles in Vista Canyon 33 03.617' 117 10.802' x Escondido Creek Escondido Creek ESC-RSFR Reach consisted of 3 riffles upstream of Rancho Santa Fe Road 33 02.365' 117 13.837' x x x San Dieguito River Green Valley Creek GVC-WB Reach consisted of 5 riffles downstream of West Bernardo Drive 33 02.625' 117 04.567' x x x x x x San Dieguito River San Dieguito River SD-DDH Reach consisted of 5 riffles along Del Dios Highway downstream of Lake Hodges 33 02.459' 117 08.595' x x x x x x Los Peñasquitos Creek Los Peñasquitos Creek LPC-CCR Reach consisted of 5 riffles upstream of Cobblestone Creek Road 32 56.949' 117 04.214' x x x x x x x x Los Peñasquitos Creek Los Peñasquitos Creek LPC-BMR Reach consisted of 5 riffles downstream of Black Mountain Road 32 56.349' 117 07.864' x x x x Los Peñasquitos Creek Los Peñasquitos Creek CCC-805 Reach consisted of 5 riffles downstream of I-805 at Sorrento Valley Road 32 53.403' 117 12.717' x x x x x x x x x Mission Bay Rose Creek MB-RC Reach consisted of 5 riffles downstream of Highway 52 32 50.056' 117 13.887' x x x x x x Mission Bay Tecolote Creek TC-TCNP Reach consisted of 4 riffles downstream of Mt. Acadia Blvd 32 47.874' 117 11.339' x x x x x x x x x San Diego River San Diego River SDR-MT Reach consisted of 5 riffles in Mission Trails Park 32 49.249' 117 03.866' x x x x x x x San Diego River San Diego River SDR-1 Reach consisted of 5 riffles downstream of Mission Valley Golf Course 32 45.736' 117 11.557' x x x x x x x San Diego Bay Chollas Creek CC-FB Reach consisted of 5 riffles downstream of Federal Boulevard 32 43.606' 117 04.219' x x x x x Sweetwater River Long Canyon Creek SR-AD Reach consisted of 5 riffles along Acacia Drive 32 39.394' 117 00.800' x Sweetwater River Sweetwater River SR-WS Reach consisted of 5 riffles along Bonita Road 32 39.436' 117 02.717' x x x x x x Sweetwater River Sweetwater River SR-94 Reach consisted of 5 riffles at Highway 94 32 44.005' 116 56.348' x x x x Tijuana River Campo Creek CC-C Reach consisted of 4 riffles up/downstream of H94 bridge in Campo 32 36.552' 116 26.448' x x x Tijuana River Campo Creek CC-H94 Reach consisted of 4 riffles at the Highway 94 USGS gauging station 32 35.456' 116 31.551' x Tijuana River Tijuana River TJ-DM Reach consisted of 5 riffles upstream of Dairy Mart Road 32 32.816' 117 03.741' x x Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-14 Figure 3-1. Stream Bioassessment Sites Sampled October 2004 and May 2005. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-15 3.2.3 Monitoring Reach Delineation The sampling points specified in the CSBP are located in a stream feature known as a riffle. An ideal riffle is an area of rapid flow with some surface disturbance and a complex and stable substrate. These areas provide increased colonization potential for benthic invertebrates. Riffles typically support the greatest diversity of organisms in a stream, and by selecting the optimal habitats available at each stream, comparability among streams is possible. Under optimal conditions, five riffles constituted a monitoring reach, and three of these were randomly selected for sampling. In some cases, particularly in low gradient streams, only three riffles could be located within a reasonable reach length, and all three were sampled. Given sufficient riffle length, a sampling transect perpendicular to stream flow was selected randomly in the upper third of the riffle. In situations where the riffle was very short or narrow, the sample was taken to best represent available substrate types. Every monitoring reach was sampled from downstream to upstream. The locations and coordinates of the monitoring reaches are presented in Table 3-2, and a map of the locations is shown in Figure 3-1. Photographs were taken of every riffle sampled and one photograph representing each monitoring reach is presented in Appendix B.1. 3.2.4 Sample Collection Once a sampling transect was established, benthic invertebrates were collected using a 1-ft-wide, 0.5- mm-mesh, D-frame kick-net. A 2-ft2 area upstream of the net was sampled by disrupting the substrate and scrubbing the cobble and boulders, so that the organisms were dislodged and swept into the net by the current. The duration of the sampling generally ranged from 1 to 3 minutes, depending on substrate complexity. Three, 2-ft2 areas were sampled along a transect and combined into a single composite sample representing 6 ft2. The three sample points on the transect were selected to represent the diversity of habitat types present. This procedure was repeated for the next two riffles until three separate replicate samples were collected. Samples were transferred to one-quart jars, and preserved with 95% ethanol, and returned to Weston’s laboratory for processing. 3.2.5 Physical Habitat Quality Assessment For each monitoring reach sampled, the physical habitat of the stream and its adjacent banks were assessed using U.S. EPA Rapid Bioassessment Protocols. Habitat quality parameters were assessed to provide a record of the overall physical condition of the reach. Parameters such as substrate complexity, channel alteration, frequency of riffles, width of riparian zones, and vegetative cover help to provide a more comprehensive understanding of the condition of the stream. Additionally, specific characteristics of the sampled riffles were recorded, including riffle length, depth, gradient, velocity, and substrate composition. Water quality measurements were taken at each of the monitoring sites using a YSI model 6600 environmental monitoring system. Measurements included water temperature, specific conductance, pH, dissolved oxygen, and chlorophyll. Chlorophyll was added to the water quality assessment in May 2003 to add information on phytoplankton productivity. Stream flow velocity was measured with a Marsh-McBirney Model 2000 portable flow meter, or was visually estimated. Physical habitat assessment Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-16 3.2.6 Laboratory Processing and Analysis At the laboratory, samples were poured over a No. 35 standard testing sieve (0.5-mm stainless steel mesh), and the ethanol was retained for re-use. The sample was gently rinsed with fresh water, and large debris, such as wood, leaves, or rocks was removed. The sample was transferred to a glass tray marked with grids 50 cm2 in size. One grid was randomly selected, and the sample material contained within that grid was removed and processed. In cases where the animals appeared extremely abundant, a fraction of the grid may have been removed. The material from the grid was examined under a stereomicroscope, and all the invertebrates were removed, sorted into major taxonomic groups, and placed in vials containing 70% ethanol. If there were less than 300 animals in the grid, another grid was selected and processed. This process was repeated until 300 organisms were removed from the sample, or until the entire sample was sorted. Organisms from a grid in excess of the 300 were counted and placed in a separate vial labeled “remaining animals,” so that a total abundance for the entire sample could be calculated. Terrestrial organisms, vertebrates, water-column associated organisms (e.g., copepods), and nematodes were not removed from the samples. Processed material from the sample was placed in a separate jar and labeled “sorted,” and the unprocessed material was returned to the original sample container and archived. Sorted material was retained for quality assurance purposes. All organisms were identified to the standard taxonomic level described in the CAMLnet List of Californian Macroinvertebrate Taxa and Standard Taxonomic Effort, using standard taxonomic keys. Quality assurance of sample sorting was performed on a minimum of 10 percent of the samples to ensure at least a 90% removal rate of organisms. Taxonomic quality assurance was performed on 10% of the samples by taxonomists at the CDFG Aquatic Bioassay Laboratory in Rancho Cordova, CA. 3.2.7 Data and Statistical Analysis A taxonomic list of BMIs identified from the samples was created using Microsoft Excel. Metric values based on the BMI community were calculated from the database. A list of these metric values and a brief description of what they signify are presented in Table 3-3. For every monitoring reach, an Index of Biotic Integrity (IBI) was calculated utilizing the most recent method developed by CDFG (Ode et al. 2005). The IBI replaces the Benthic Macroinvertebrate Index (BMI) Ranking Score used in past analyses and is a significant improvement because it gives an absolute value to the benthic community quality based on the range of reference conditions in the region. The IBI can also be used to evaluate community conditions over time to monitor the effects of habitat degradation or the success of restoration efforts. Additional analysis of the data included a comparison of IBI scores with habitat quality, and an analysis of the trends of the monitoring results since the beginning of the program in May of 2001. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-17 Table 3-3. Bioassessment Metrics Used to Characterize BMI Communities. BMI Metric Description Response to Impairment Richness Measures Taxa Richness Total number of individual taxa Decrease EPT Taxa Number of taxa in the Ephemeroptera (mayfly), Plecoptera (stonefly) and Trichoptera (caddisfly) insect orders Decrease Dipteran Taxa Number of taxa in the insect order (Diptera, “true flies”) Increase Non-Insect Taxa Number of non-insect taxa Increase Composition Measures EPT Index Percent composition of mayfly, stonefly, and caddisfly larvae Decrease Sensitive EPT Index Percent composition of mayfly, stonefly, and caddisfly larvae with tolerance values between 0 and 3 Decrease Shannon Diversity Index General measure of sample diversity that incorporates richness and evenness (Shannon and Weaver 1962) Decrease Tolerance/Intolerance Measures Tolerance Value Value between 0 and 10 weighted for abundance of individuals designated as pollution tolerant (higher values) or intolerant (lower values) Increase Percent Dominant Taxa Percent composition of the single most abundant taxon Increase Percent Chironomidae Percent composition of the tolerant dipteran family Chironomidae Increase Percent Intolerant Organisms Percent of organisms in sample that are highly intolerant to impairment as indicated by a tolerance value of 0, 1 or 2 Decrease Percent Tolerant Organisms Percent of organisms in sample that are highly tolerant to impairment as indicated by a tolerance value of 8, 9 or 10 Increase Functional Feeding Groups (FFG) Percent Collector-gatherers Percent of macrobenthos that collect or gather fine particulate matter Increase Percent Collector-filterers Percent of macrobenthos that filter fine particulate matter Increase Percent Scrapers Percent of macrobenthos that graze upon periphyton Variable Percent Predators Percent of macrobenthos that prey on other organisms Variable Percent Shredders Percent of macrobenthos that shreds coarse particulate matter Decrease Percent Others Percent of macrobenthos that are parasites, macrophyte herbivores, piercer herbivores, omnivores, and xylophages Variable Abundance Estimated Abundance Estimated number of BMIs in sample calculated by extrapolating from the proportion of organisms counted in the subsample Variable Source: SDRWQCB 1999 Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-18 3.3 Ambient Bay and Lagoon Monitoring Under the NPDES permit granted to the County of San Diego by the San Diego Regional Water Quality Control Board, the Copermittees are required to develop and implement a program to assess the overall health of the receiving waters and monitor the impact of urban runoff on ambient receiving water quality. This program, known as the Ambient Bay and Lagoon Monitoring (ABLM) Program, is intended to include San Diego Bay, Mission Bay, Oceanside Harbor, the Pacific Coastline, coastal lagoons and estuaries, and all Clean Water Act section 303(d) water bodies or other environmentally sensitive areas. To implement the second year of this monitoring program, evaluations of sediment chemistry, sediment toxicity, and ecological community (benthic infauna) structure in the coastal embayments (lagoons and bays) of San Diego County were monitored and analyzed. Data from these evaluations are intended to provide an indication of how marine life in the bays and lagoons is affected by pollution, and allow prioritization of outfall areas of coastal embayments for additional investigation in subsequent years. The data assessed in this report were from samples collected in the summer of 2004. 3.3.1 Objectives and Approach The ABLM program has several objectives: • to fulfill NPDES requirements for San Diego County, • to initiate a regional study of coastal embayments, • to assess the overall health of the receiving waters, and • to monitor the impact of urban runoff on ambient water quality. The first step in fulfilling the objectives was to conduct a literature review to determine what information and data were available that could be used to design an appropriate monitoring program. The relevant data and information were used to create the sampling design, assess its validity using empirical data from other studies, and delineate the appropriate sampling effort. This was done prior to the first year’s sampling in the summer of 2003. The literature review covered southern California bays and lagoons: Newport Bay, Santa Margarita River and Estuary, Oceanside Harbor, San Luis Rey River and Estuary, Batiquitos Lagoon, San Elijo Lagoon, Aqua Hedionda Lagoon, Buena Vista Lagoon, San Dieguito Estuary, and Los Peñasquitos Lagoon. Documents and data more than 10 years old were considered non-reflective of current conditions in most of these bays and lagoons and therefore excluded from the review. The literature review targeted information related to sediment grain size, organic carbon concentrations, sediment toxicity, bacteria, infaunal communities, and contaminant concentrations. Data were sought that could be related to gradients within each water body, i.e. information near watershed inputs, middle lagoon or bay, and areas furthest from potential watershed inputs. Information was available for all these areas but there was little consistency on the parameters measured or the methods utilized. Most of the sampling and monitoring conducted within the target sites related to water quality measures and only a few locations were related to sediment parameters. The results of the literature review demonstrated that the physical characteristics and depositional patterns within coastal embayments vary spatially in a longitudinal and lateral sense. There are wide variations in sediment characteristics within coastal embayments because of temporal variations in deposition patterns, the influence of stream and tidal channels, sequestering of contaminants by marshes Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-19 and grasses, and connectivity with the ocean. Sediments that accumulate in coastal embayments as a result of urban runoff are dispersed according to the different energy conditions that are encountered at stream outfalls and in the embayment. Fine-grained sediments tend to accumulate in lower energy conditions between active stream and tidal channels; whereas, coarser sediments accumulate in stream and tidal channels as point bars. This variability complicates measuring and assessing the concentration and distribution of contaminants and requires that care be taken to specify the frequency and locations of field samples. Site assessments are further complicated by seasonal effects, which can be regular, or atypical, caused by drought that can reduce sediment outflow or high-energy storms that can displace large amounts of sediments and significantly alter the distribution and availability of contaminants. Accounting for this inherent variability in monitoring coastal embayments requires comprehensive site assessments that reflect the possible range of variability of both long-term, periodic variations and infrequent, but often high-energy, episodic events. Such comprehensive assessments can be extremely labor intensive and expensive. Thus, rather than trying to directly measure contaminant loading in the water, the approach that was used in the ABLM Program focuses on the receiving water sediments where contaminants are most likely to be found. It was clear from the literature review that fine-grained sediment particles in the size range typical of silts and clays (<64 microns in diameter) are favored adsorption sites for most contaminants found in the waters of coastal wetlands (Gibbs 1973, Moore et al. 1989, Kennish 1998). Fine-grained sediments tend to have large surface areas with unsatisfied surface charges that promote adsorption of ionic complexes of metals, PCBs, PAHs, and pesticides. This association is particularly strong where fine-grained sediments are associated with high levels of total organic carbon (TOC). Additionally, fine-grained, organic sediment in overabundance can overwhelm the endemic flora and fauna of lagoons and estuaries. Because of their ability to compound and adsorb pollutants, fine-grained sediments with high TOC content are the most likely to be influenced by watershed contaminants and thus pose the greatest threat to the biological communities in the embayment. 3.3.2 Validation of Approach To validate this association, information from benthic sediment quality and toxicity monitoring conducted in Newport Bay, California in 1994 (EMAP 1997) was assessed to determine if the sediments with the highest TOC concentrations and greatest proportion of fines also had the highest concentrations of contaminants. Samples taken from 12 sites in Newport Bay (includes upper, middle, and outer areas of the Bay) were ranked according to their grain size and TOC concentration. The ranks were summed and the summed ranks were separated into four groups of three samples each, according to the sediment ranks. Group 1 was the group with the highest TOC concentration and finest grain sediments. Concentrations of several contaminants (16 metals, total DDT, total PAHs, and chlordane) and amphipod toxicity were then compared between the groups by analysis of variance (ANOVA). The purpose of the ANOVA was to see if Group 1 (the “finest grain, highest TOC” group) also had higher contaminant levels. The results of the analyses are presented in Table 3-4. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-20 Table 3-4. Results of ANOVA on 1994 Newport Bay data. Constituent of Concern Prob > F Tukey-Kramer Comparison Groups Highest to Lowest Aluminum 0.174 4 2 3 1 Antimony 0.007 1 2 3 4 Arsenic 0.726 1 3 2 4 Cadmium 0.006 2 1 3 4 Chromium 0.010 1 2 3 4 Copper 0.014 1 3 2 4 Iron 0.004 1 2 3 4 Lead 0.541 1 2 3 4 Manganese 0.485 1 2 4 3 Mercury 0.449 3 1 4 2 Nickel 0.014 1 2 3 4 Silver 0.127 2 4 3 1 Selenium 0.027 1 2 3 4 Tin 0.017 1 2 3 4 Zinc 0.003 1 2 3 4 DDT 0.001 1 2 3 4 PAH 0.129 1 2 3 4 Chlordane 0.007 2 1 3 4 R. abronius mortality 0.132 2 1 3 4 Eleven of the 20 ANOVAs were significant (at a 95% confidence). For nine of the contaminants, Group 1 was the highest in concentration and Group 4, with the lowest TOC and fine grains, was always the lowest in concentration. In the remaining nine tests with non-significant results, four contaminants also had highest concentrations in Group 1. The results of the analysis verify other studies that suggest that Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-21 areas with finer grain size and higher TOC concentration also tend to have higher contaminant levels and thus represent the “worst case” condition of the coastal embayment. The ABLM Program utilized the association between small grain size, high TOC levels, and contaminants to spatially target areas in each embayment where contaminants were most likely to be found. The ABLM Program will be conducted over several years to assess the temporal trends of the major coastal embayments in San Diego County. During each year, the program will be conducted in two phases: • Phase I – Contaminant Targeting: three areas in each embayment with the finest grain size and highest TOC concentration will be identified using a stratified random design. • Phase II – Sediment Assessment: the areas identified in Phase I will be assessed using the same “triad” approach that is being utilized for the storm water runoff program: chemistry, toxicity, and biology of the sediments. During the second year of the program, the field assessment was conducted in June 2004 for Phase I and in July 2004 for Phase II. The results are presented in this report. 3.3.3 Phase I – Contaminant Targeting 3.3.3.1 Site Locations Twelve coastal embayments in San Diego County were monitored as part of the ABLM Program (Table 3-5). Table 3-5. Coastal embayments monitored in the Ambient Bay and Lagoon Monitoring Program. Name of Coastal Embayment Site Designation Watershed Management Area Major Freshwater Tributary Santa Margarita River Estuary SME Santa Margarita River Santa Margarita River Oceanside Harbor OH Santa Margarita River None San Luis Rey River Estuary SLE San Luis Rey River San Luis Rey River Buena Vista Lagoon BVL Carlsbad Buena Vista Creek Agua Hedionda Lagoon AHL Carlsbad Agua Hedionda Creek Batiquitos Lagoon BL Carlsbad San Marcos Creek San Elijo Lagoon SEL Carlsbad Escondido Creek San Dieguito Lagoon SDL San Dieguito San Dieguito Creek Los Peñasquitos Lagoon LPL Peñasquitos Los Peñasquitos Creek Mission Bay (includes Rose and Tecolote Creek outfalls) MB Mission Bay Tecolote Creek and Rose Creek Sweetwater River Estuary SRE San Diego Bay Sweetwater River Tijuana River Estuary TRE Tijuana River Tijuana River The embayments are shown graphically in Figure 3-2. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-22 Figure 3-2. Map of coastal embayments monitored in the Ambient Bay and Lagoon Monitoring Program. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-23 3.3.3.2 Sampling Design A stratified random approach was used to select sampling sites within each embayment. First, the area of each embayment that is tidally influenced at mean lower low water (MLLW) was delineated on aerial photographs using GIS. Tidal extent was determined from U.S. Geological Survey topographical maps, published reports showing tidal extent, and visual observations. Then, to provide complete spatial coverage, each embayment was stratified into three strata using GIS: Stratum 1 - an outer stratum located nearest the ocean; Stratum 2 - a middle stratum, centered upon the lagoon; and Stratum 3 - an inner stratum, located nearest the major watershed input source. Each of these three strata was further divided into three areas roughly along the longitudinal axis of the embayment: right bank (looking downstream), center, and left bank. Thus, nine strata were delineated in each embayment. Each of these areas was digitized using GIS. Within the polygon representing each stratum, a series of random points was created using a random point’s generator, an extension of ArcView that generates a user specified number of random points within polygons. A minimum distance of 100 feet was specified between points. The first random point generated by the program and the corresponding latitude and longitude coordinates for each of the nine strata was mapped on the aerial photographs for all of the coastal embayments. As many as five additional points per strata were also generated in case the first point selected was found to be inaccessible in the field. The sampling site locations identified by this process for each of the coastal embayments are presented in Table 3-6. Table 3-6. Ambient Bay and Lagoon Phase I site locations. Embayment Site Number Latitude Longitude Embayment Site Number Latitude Longitude SME 1L-2 N33° 13.811’ W117° 24.779’ BL 1L-1 N33° 05.152’ W117° 18.357’ SME 1M-1 N33° 13.947’ W117° 24.814’ BL 1M-1 N33° 05.368’ W117° 18.226’ SME 1R-1 N33° 13.996’ W117° 24.835’ BL 1R-1 N33° 05.354’ W117° 18.319’ SME 2L-1 N33° 13.945’ W117° 24.736’ BL 2L-1 N33° 05.266’ W117° 17.516’ SME 2M-1 N33° 14.061’ W117° 24.639’ BL 2M-1 N33° 05.421’ W117° 17.990’ SME 2R-2 N33° 14.112’ W117° 24.551’ BL 2R-1 N33° 05.374’ W117° 17.455’ SME 3L-1 N33° 14.145’ W117° 24.085’ BL 3L-1 N33° 05.317’ W117° 17.254’ SME 3M-1 N33° 14.146’ W117° 24.283’ BL 3M-1 N33° 05.368’ W117° 17.226’ SME 3R-3 N33° 14.170’ W117° 24.094’ BL 3R-1 N33° 05.422’ W117° 17.253’ OH 1L-1 N33° 12.445’ W117° 24.005’ SEL 1L-1 N33° 00.676’ W117° 16.474’ OH 1M-1 N33° 12.485’ W117° 24.155’ SEL 1M-1 N33° 00.661’ W117° 16.447’ OH 1R-1 N33° 12.646’ W117° 24.328’ SEL 1R-1 N33° 00.837’ W117° 16.780’ OH 2L-1 N33° 12.438’ W117° 23.904’ SEL 2L-1 N33° 00.605’ W117° 16.282’ OH 2M-1 N33° 12.570’ W117° 24.061’ SEL 2M-1 N33° 00.583’ W117° 16.263’ OH 2R-2 N33° 12.656’ W117° 23.992’ SEL 2R-1 N33° 00.320’ W117° 16.153’ OH 3L-1 N33° 12.312’ W117° 23.380’ SEL 3L-2 N33° 00.380’ W117° 15.973’ OH 3M-1 N33° 12.484’ W117° 23.738’ SEL 3M-1 N33° 00.389’ W117° 15.991’ OH 3R-1 N33° 12.343’ W117° 23.798’ SEL 3R-1 N33° 00.397’ W117° 16.000’ SLE 1L-1 N33° 12.158’ W117° 23.362’ SDL 1L-1 N32° 58.168’ W117° 15.679’ SLE 1M-1 N33° 12.197’ W117° 23.335’ SDL 1M-1 N32° 58.189’ W117° 15.680’ SLE 1R-1 N33° 12.218’ W117° 23.328’ SDL 1R-1 N32° 58.284’ W117° 15.819’ SLE 2L-1 N33° 12.229’ W117° 23.258’ SDL 2L-1 N32° 57.797’ W117° 15.264’ SLE 2M-1 N33° 12.334’ W117° 23.161’ SDL 2M-1 N32° 57.968’ W117° 15.237’ Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-24 Table 3-6. Ambient Bay and Lagoon Phase I site locations. Embayment Site Number Latitude Longitude Embayment Site Number Latitude Longitude SLE 2R-1 N33° 12.245’ W117° 23.282’ SDL 2R-1 N32° 58.042’ W117° 15.389’ SLE 3L-1 N33° 12.555’ W117° 22.849’ SDL 3L-1 N32° 58.374’ W117° 14.865’ SLE 3M-1 N33° 12.507’ W117° 22.889’ SDL 3M-1 N32° 58.199’ W117° 15.548’ SLE 3R-1 N33° 12.422’ W117° 23.065’ SDL 3R-1 N32° 58.182’ W117° 15.598’ BVL 1L-1 N33° 09.947’ W117° 21.462’ LPL 1L-1 N32° 55.883’ W117° 15.541’ BVL 1M-1 N33° 10.046’ W117° 21.391’ LPL 1M-1 N32° 55.936’ W117° 15.470’ BVL 1R-1 N33° 10.033’ W117° 21.421’ LPL 1R-2 N32° 55.954’ W117° 15.490’ BVL 2L-1 N33° 10.204’ W117° 21.041’ LPL 2L-4 N32° 55.869’ W117° 15.205’ BVL 2M-1 N33° 10.087’ W117° 21.164’ LPL 2M-2 N32° 55.973’ W117° 15.283’ BVL 2R-1 N33° 10.397’ W117° 21.097’ LPL 2R-1 N32° 55.916’ W117° 15.211’ BVL 3L-1 N33° 10.671’ W117° 20.551’ LPL 3L-1 N32° 55.866’ W117° 15.061’ BVL 3M-1 N33° 10.646’ W117° 20.623’ LPL 3M-2 N32° 55.859’ W117° 15.014’ BVL 3R-1 N33° 10.708’ W117° 20.674’ LPL 3R-2 N32° 55.876’ W117° 15.041’ AHL 1L-1 N33° 08.665’ W117° 20.542’ MB 1L-1 N32° 45.587’ W117° 14.360’ AHL 1M-1 N33° 08.454’ W117° 20.357’ MB 1M-1 N32° 45.634’ W117° 14.656’ AHL 1R-1 N33° 08.598’ W117° 20.377’ MB 1R-1 N32° 47.296’ W117° 14.685’ AHL 2L-2 N33° 08.501’ W117° 19.850’ MB 2L-1 N32° 46.518’ W117° 13.525’ AHL 2M-2 N33° 08.713’ W117° 20.136’ MB 2M-1 N32° 46.267’ W117° 14.036’ AHL 2R-1 N33° 08.775’ W117° 19.998’ MB 2R-1 N32° 46.746’ W117° 14.054’ AHL 3L-1 N33° 08.394’ W117° 19.420’ MB 3L-1 N32° 46.998’ W117° 12.889’ AHL 3M-1 N33° 08.381’ W117° 19.096’ MB 3M-1 N32° 47.047’ W117° 12.798’ AHL 3R-1 N33° 08.511’ W117° 19.341’ MB 3R-1 N32° 47..012’ W117° 12.740’ SRE 1L-1 N32° 38.916 W117° 06.670 TRE 1L-2 N32° 33.288’ W117° 07.622’ SRE 1M-1 N32° 38.940 W117° 06.629 TRE 1M-1 N32° 33.382’ W117° 07.646’ SRE 1R-1 N32° 38.899 W117° 06.883 TRE 1R-2 N32° 33.761’ W117° 07.824’ SRE 2L-1 N32° 39.095 W117° 06.030 TRE 2L-1 N32° 33.263’ W117° 07.297’ SRE 2M-2 N32° 39.030 W117° 06.302 TRE 2M-1 N32° 33.419’ W117° 07.580’ SRE 2R-1 N32° 39.026 W117° 06.424 TRE 2R-1 N32° 33.476’ W117° 07.444’ SRE 3L-1 N32° 39.341 W117° 05.349 TRE 3L-21 N32° 33.493’ W117° 07.190’ SRE 3M-1 N32° 39.285 W117° 05.477 TRE 3M-1 N32° 33.462’ W117° 07.384’ SRE 3R-1 N32° 39.287 W117° 05.518 TRE 3R-1 N32° 33.520’ W117° 07.181’ In the field, the aerial photographs with the identified sampling sites and a hand-held global positioning system (GPS) unit were used to locate the first sampling site identified by the random point generator. Each site was accessed by a survey team of two people with an inflatable boat or by land depending on the sampling location. If the first location was inaccessible or was not considered part of the delineated embayment, the next randomly selected site was located until an accessible sampling point was identified. Sites were considered inaccessible if the GIS coordinates generated by the random point generator were found in the field to be on land, in an area with impermeable substrate (e.g., rip rapped channels), or that could not be accessed by land or by boat. This process was repeated for all nine pre-determined areas of the embayment. Sediment samples were collected at each of the nine sampling points per embayment and analyzed for grain size and TOC content as described below. A summary of the Phase I sampling protocol is presented in Table 3-7. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-25 Sediment sample in push core Table 3-7. Summary of Phase I field and analytical activities of the Ambient Bay and Lagoon Monitoring Program. Field Collection Parameter Site Analysis Total Samples Analyzed per Embayment Field Completion Date Total Organic Carbon and Grain Size Stratum 1 Right Middle Left Stratum 2 Right Middle Left Stratum 3 Right Middle Left Individual Individual Individual Individual Individual Individual Individual Individual Individual 3 3 3 June 30, 2004 3.3.3.3 Sample Collection Most of the sampling sites were accessed from the water with an inflatable raft powered by an 8 hp motor. Sites that were inaccessible by water were accessed by land where possible. Some sites were considered inaccessible due to difficult terrain or the presence of sensitive habitat, wildlife, or vegetation. Once the sampling site had been located in the field, a sediment sample was taken with a push core. Upon retrieval, the bottom of the sediment in the core was removed so that only the top 5 cm of sediment remained in the core. Both ends of the core were then capped, labeled with the appropriate site information, and placed on ice in a cooler. All samples were transported on ice to the laboratory. In the laboratory, each sample was split and placed into two individual containers. The samples for TOC analysis were placed in the freezer and stored at –8oC. Samples for grain size analysis were stored in the refrigerator at 4oC. In the laboratory, sediment TOC levels were analyzed by method ASTM D2579, modified. Sediment grain size was analyzed using a technique employed by Plumb (1981) based on procedures for Handling and Chemical Analysis of Sediment and Water Samples. 3.3.4 Phase II – Sediment Assessment 3.3.4.1 Priority Ranking After sediment samples from the nine sites in each of the twelve embayments were analyzed, the sites in each embayment were ranked based on the percentage of fine grained sediments and TOC levels. The sites with the smallest grain size (i.e., the highest percentage of fine-grained sediments) received the Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-26 highest rank for grain size and the sites with the highest TOC content received the highest rank for TOC. The ranks for grain size and TOC at each site were then summed to produce an overall rank for that site. The three sites in each embayment with the highest ranks were assessed in Phase II of the program, which was conducted in July 2004. In the case of a tie in the summed ranks, the site with the higher fines rank was selected for Phase II assessment. 3.3.4.2 Sample Collection Phase II sampling took place from July 11 to July 26, 2004. Stations were located with a hand-held GPS and accessed as described for Phase I. At each station, several water quality parameters were measured and sediment samples collected for analyses. The parameters and sample types are listed below. • In situ water quality measurements and visual observations, • Sediment chemistry, • Sediment toxicity, • Benthic Infauna. At each station, water quality parameters were collected with a portable probe and recorded on data sheets in the field. Three separate sediment samples were collected with a 0.1 m2 Van Veen sampler for sediment chemistry, sediment toxicity, and infaunal assessment. Details of each of these parameters are discussed below. 3.3.4.3 Water Quality At each station, a YSI model 6600 portable multi-probe was positioned approximately six inches above the sediment/water interface and the following parameters were measured: depth, temperature, DO, pH, and conductivity. The data was recorded on data sheets in the field. In addition to water quality measurements, the following visual observations were also recorded at each site: percent cover of algae or grasses, sediment type, color, and odor (such as hydrogen sulfide). A photograph of a sediment sample at each station was taken in the field before the sample was disturbed. 3.3.4.4 Sediment Chemistry At each of the three stations identified in Phase I, a separate grab sample was taken for sediment chemistry analysis utilizing a 0.1 m2 Van Veen. Upon retrieval of the grab, the surface of the sample was inspected for acceptability. To be acceptable, the surface of the grab must be even, with minimal surface disturbance and little or no leakage of overlying water. If the grab was acceptable, the overlying water was carefully drained. If a grab was not acceptable, additional samples were taken. For sediment chemistry analyses, the top 5 cm of sediment was removed for analyses. Care was taken not to disturb the sediment or remove sediment that was within 1 cm of the sides of the sampler. A total volume of approximately one liter was taken for analysis. Samples were placed into a labeled container, put on ice, and transported to the on-shore processing facility. Samples from each of the three stations per embayments were composited in the field in stainless steel bowls for analyses. Thus, one composite sample was analyzed from each embayment. Samples were then placed in appropriate containers, labeled, and placed on ice in a cooler. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-27 Sediment samples for chemical analyses were sent on ice to EnviroMatrix Analytical Laboratories in San Diego, California for analysis. In the laboratory, the samples were analyzed for several metals, organochlorine and organophosphate pesticides, PCBs, and PAHs. Testing parameters and analytical procedures are listed in Table 3-8. 3.3.4.5 Sediment Toxicity Sampling procedures described for sediment chemistry were also utilized for sediment toxicity testing. As described above, a single composite from three locations in each embayment were utilized for toxicity testing. At Weston Solutions’ bioassay facility in Carlsbad, CA., U.S. EPA guidelines (USEPA 1994) were used to assess sediment toxicity with a 10-day acute test using the estuarine amphipod Eohaustorius estuarius (Table 3-8). This test consists of a 10-day exposure of E. estuarius to sediment under static conditions. Amphipods are placed in glass chambers containing seawater and a 2-cm layer of test sediment. The number of surviving amphipods is measured at the end of the test and is used to calculate the percentage survival. Individuals were visually inspected to confirm proper size and healthy condition prior to use in sediment testing. All tests were initiated within 10 days of collection. Water quality measurements were made at the beginning and end of exposure and temperature was continuously measured in the exposure room. 3.3.4.6 Benthic Infauna For the benthic infauna assessment, a separate sample was collected at each station with a 0.1-m2 Van Veen. The whole sample was placed into a labeled plastic bag and transported to shore to a mobile processing station. At the processing station, the sample was sorted through a 1.0-mm sieve. Retained organisms and sediments were fixed in a buffered formalin solution and returned to the laboratory for processing and preservation. The infaunal samples were taken from the same stations as samples for sediment chemistry and toxicity, however, the infaunal samples were not composited. Thus, there were three samples per embayment retained for infaunal analyses. At Weston Solutions’ facility in Carlsbad, CA, infaunal samples were transferred from formalin solution to alcohol for processing. Organisms were separated from the sediments by trained technicians using dissecting microscopes into five major taxonomic groups: arthropoda (insects and crustaceans), annelida (worms), mollusca, echinodermata, and miscellaneous minor phyla. Upon completion of the sorting, the taxonomic groups were distributed to taxonomic experts in each of the categories for counting and identification of the organisms. The field and analytical elements of Phase I and Phase II activities are summarized in Table 3-9. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-28 Table 3-8. Analytical parameters for the Ambient Bay and Lagoon Monitoring Program. Constituent Volume Required Method MDL Units General Physical and Inorganic Non-Metals Temperature In field na na oC DO In field na na mg/l pH In field na na S.U. Specific Conductance In field na na μmhos/cm Turbidity In field na na NTUs Total Organic Carbon (TOC) 125 g ASTM D-2579 1.0 % Grain Size 125 g Plumb 1981 1.0 % dry wt PAHs Acenaphthene 100 g GC/MS SIMS 3.60 μg/kg dry wt Acenaphthylene 100 g GC/MS SIMS 4.68 μg/kg dry wt Anthracene 100 g GC/MS SIMS 6.30 μg/kg dry wt Benzo (a) anthracene 100 g GC/MS SIMS 6.67 μg/kg dry wt Benzo (b) fluoranthene 100 g GC/MS SIMS 8.89 μg/kg dry wt Benzo (k) fluoranthene 100 g GC/MS SIMS 6.84 μg/kg dry wt Benzo (g,h,i) perylene 100 g GC/MS SIMS 9.72 μg/kg dry wt Benzo (a) pyrene 100 g GC/MS SIMS 7.38 μg/kg dry wt Chrysene 100 g GC/MS SIMS 3.96 μg/kg dry wt Dibenz (a,h) anthracene 100 g GC/MS SIMS 9.18 μg/kg dry wt Fluoranthene 100 g GC/MS SIMS 5.76 μg/kg dry wt Fluorene 100 g GC/MS SIMS 4.68 μg/kg dry wt Indeno (1,2,3-cd) pyrene 100 g GC/MS SIMS 10.0 μg/kg dry wt Naphthalene 100 g GC/MS SIMS 1.91 μg/kg dry wt Phenanthrene 100 g GC/MS SIMS 4.19 μg/kg dry wt Pyrene 100 g GC/MS SIMS 6.08 μg/kg dry wt PCBs Aroclor 1016 100 g EPA 8082 4.68 μg/kg dry wt Aroclor 1221 100 g EPA 8082 4.68 μg/kg dry wt Aroclor 1232 100 g EPA 8082 4.68 μg/kg dry wt Aroclor 1242 100 g EPA 8082 4.68 μg/kg dry wt Aroclor 1248 100 g EPA 8082 4.68 μg/kg dry wt Aroclor 1254 100 g EPA 8082 4.68 μg/kg dry wt Aroclor 1260 100 g EPA 8082 4.68 μg/kg dry wt Chlorpyrifos 100 g EPA 8141A 0.002 mg/kg Diazinon 100 g EPA 8141A 0.002 mg/kg Metals (Total) Antimony (Sb) 200 g EPA 6020 0.6 mg/kg dry wt Arsenic (As) 200 g EPA 6020 0.2 mg/kg dry wt Cadmium (Cd) 200 g EPA 6020 0.1 mg/kg dry wt Chromium (Cr) 200 g EPA 6020 0.4 mg/kg dry wt Copper (Cu) 200 g EPA 6020 0.4 mg/kg dry wt Lead (Pb) 200 g EPA 6020 0.1 mg/kg dry wt Nickel (Ni) 200 g EPA 6020 0.2 mg/kg dry wt Selenium (Se) 200 g EPA 6020 0.6 mg/kg dry wt Zinc (Zn) 200 g EPA 6020 2.2 mg/kg dry wt Toxicity - 10 day acute with Eohaustorius estuarius 2.5 L EPA 1995 na na na = not applicable Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-29 Table 3-9. Summary of Phase II field and analytical activities of the Ambient Bay and Lagoon Monitoring Program. Field Collection Parameter Site Analysis Total Samples Analyzed per Embayment Completion Date Sediment Chemistry (Plus TOC & GS) Sediment Toxicity Infaunal Community Analysis Station 1* Station 2 Station 3 Station 1* Station 2 Station 3 Station 1* Station 2 Station 3 Composite of 3 Individual samples Composite of 3 Individual samples Individual Individual Individual 1 1 3 July 30, 2004 * Locations of Stations 1, 2, and 3 were derived from the results of Phase I. 3.3.5 Data Assessment 3.3.5.1 Sediment Chemistry Currently, there are no universally accepted criteria for assessing contaminated sediments. However, the Effect Range Low (ERL) and Effect Range Median (ERM) values originally developed by Long and Morgan (1990) and subsequently revised and expanded upon by Long and MacDonald (1992) and Long et al. (1995) can be used to evaluate the potential for sediment to cause adverse biological effects (Table 3- 10). These parameters were developed from a large data set where results of both sediment toxicity bioassays (e.g., amphipod tests) and chemical analyses were available for individual samples. The guidelines were intended to provide informal (non-regulatory) effects-based benchmarks of sediment chemistry data (Long et al. 1998). Two effects categories have been identified: ERL – Effects Range Low: concentrations below which adverse biological effects are rarely observed; and ERM – Effects Range Medium: concentrations above which adverse biological effects are more frequently, though not always observed. Sediment chemistry data from samples collected from each of the coastal embayments were compared to the ER-L and or the ER-M data. Because the ABLM program utilizes an approach that targets COCs in each embayment (using TOC and grain size parameters), the individual assessments represent a worst- case scenario rather than a representative assessment of the embayment. The data should be interpreted to reflect this important distinction. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-30 Table 3-10. Sediment Effects Guideline Values. Parameter Effects Range-Low (ER-L) Effects Range-Median (ER-M) Metals (mg/Kg) Antimony 2.0 2.5 Arsenic 8.2 70 Cadmium 1.2 9.6 Chromium 81 370 Copper 34 270 Lead 46.7 218 Nickel 20.9 51.6 Zinc 150 410 Organics (μg/Kg) Acenaphthene 16 500 Acenaphthylene 44 640 Anthracene 85.3 1,100 Fluorene 19 540 Naphthalene 160 2,100 Phenanthrene 240 1,500 Low-molecular weight PAH 552 3,160 Benz(a)anthracene 261 1,600 Benzo(a)pyrene 430 1,600 Chrysene 384 2,800 Dibenzo(a,h)anthracene 63.4 260 Fluoranthene 600 5,100 Pyrene 665 2,600 High molecular weight PAH 1,700 9,600 Total PAH 4,022 44,792 Total PCBs 22.7 180 Source: Long et al. 1995 ER-L = Concentration at lower tenth percentile at which adverse biological effects were observed or predicted. ER-M = Concentration at which adverse biological effects were observed or predicted in 50% of test organisms. mg/Kg = milligrams per kilogram. μg /Kg = micrograms per kilogram. In addition, for each embayment ERM values were used to calculate a mean ERM quotient (ERM-Q). The concentration of each COC was divided by its ERM to produce a quotient, or proportion of the ERM equivalent to the magnitude by which the ERM value is exceeded or not exceeded. The mean ERM-Q for each embayment was then calculated by summing the ERM-Qs for each COC and then dividing by the total number of ERM-Qs assessed. ERM-Qs were not calculated for COCs below the detection limit and thus were not used in the generation of the mean ERM-Q. The mean ERM-Q thus represents an assessment for each embayment of the cumulative sediment chemistry relative to the threshold values. In this way, the cumulative risks of effect to the benthic community can provide a mechanism to compare embayments. This method has been used and evaluated by several researchers (Hyland et al. 1999, Carr et al. 1996, Chapman 1996, and Long et al. 1995) throughout the country. The aggregate approach using an ERM-Q is a more reliable predictor of potential toxicity but should not be used to infer causality of specific contaminants. ERL and ERM values were originally derived to be broadly applicable and they cannot account for site-specific features that may affect their applicability on a Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-31 more local or regional level. Local differences in geomorphology can result in chemicals being more or less available and therefore more or less toxic than an ERL or ERM value might indicate. Additionally, some regions of the country are naturally enriched in certain metals and local organisms have become adapted. 3.3.5.2 Sediment Toxicity Sediment toxicity results were obtained from the exposure of the test species (E. estuarius) to sediments collected from each of the embayments. The percent survival of test organisms in sediments from the embayments was compared to percent survival in a control sample to assess benthic infaunal toxicity levels from each of the embayments sampled. A statistical evaluation was conducted for each of the embayments to determine if there is a statistically significant difference (using ANOVA) between toxicity in sediments from the embayment verses toxicity in the control. In addition to the individual assessments of each embayment, the toxicity results were used to rank each of the embayments. The ranking was based on the percent survival of E. estuarius in the 10-day acute test, where the highest survival (lowest toxicity) receives a rank of 1 and the lowest survival (highest toxicity) receives a rank of 12. 3.3.5.3 Benthic Infauna Data The benthic infauna data from each of the embayments was assessed using a variety of indices common to ecological community structure evaluations. Some of the tools that are employed in the assessment include a species list, relative abundance, species diversity or richness, Shannon-Wiener Species Diversity Index, and an evaluation of the presence of sensitive and pollutant tolerant species. This information was incorporated into a two-way coincidence table that was used to perform a cluster analysis. The cluster analysis shows the relationship between the individual embayments and the various indicators used to describe the characteristics of the benthic infaunal community. Embayments with similar index or parameter scores will cluster together, providing a means by which the embayments can be ranked from best (least impacted community) to worst (most impacted community). The results of the cluster analyses were also used to provide an individual assessment of each embayment. 3.3.5.4 Data Integration Once all the ABLM data were available, a triad matrix was developed so that the combination of sediment chemistry, sediment toxicity, and benthic infauna data was used to develop a ranking of the embayments across the County (or in a watershed). For each of the embayments, the three elements of the monitoring program were ranked individually for each site (1 to 12 for the 12 embayments assessed) as follows: Sediment Chemistry – The mean ERM-Q value was used, where 1 represents low potential for toxicity and 12 represents high potential for toxicity; Sediment Toxicity – The results of the E. estuarius percent survival was used to rank each site, where 1 represents lower toxicity and 12 represents higher toxicity. Benthic Infauna – The results of the benthic community indices were used to rank each site, where 1 represents the best relative score (e.g. highest diversity) and 12 represents the worst score (e.g. lowest diversity). Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-32 The individual ranks for each of the monitoring elements were added together and then these sums were used to develop an overall relative summed rank (where 1 represents the lowest summed score and 12 represents the highest summed score) of each embayment relative to the other embayments. 3.4 Watershed Management Area Assessment and Long-Term Effectiveness Assessment Rating Methods 3.4.1 Watershed Management Area Assessment Methods The watershed data assessments were prepared using the interim guidance document “Watershed Data Assessment Framework” (June 2004) which closely resembles the “Model Storm Water Monitoring Program for Municipal Separate Storm Sewer Systems in Southern California” developed by the Storm Water Monitoring Coalition’s (SMC) Model Monitoring Technical Committee. A complete description of methods and tools used to perform the watershed assessment can be found in the guidance document. The watershed assessments are intended to provide a management tool for Copermittees to utilize in the development of short and long-term actions to address potential or actual water quality problems in the watershed. During the annual water quality assessment, the high, medium or low frequency of occurrence for COC(s) is evaluated for each watershed using the latest data collected and potential water quality issues are determined. In some cases confirmation of water quality problems will require that additional data be collected or assessed to understand the extent of the problem. Additional information to assess if a water quality problem exists may be available from third party data or a special study that can be used to answer questions relating to sources of the COC(s). In some instances, data from third parties or special studies may be used to further define the problem both spatially and temporally. The watershed assessment process leads to a prioritization of water quality issues by individual Watershed Copermittees and should assist them in short and long-term planning efforts, and developing activities directed at maintaining or improving water quality. The watershed assessment process can be broken into seven steps: 1. Compare chemistry results to action levels and water quality objectives 2. Examine exceedance percentages, bioassessment rankings and toxicity results 3. Apply the Interim Criteria Ranking System to results 4. Evaluate third party data and 303(d) listing information 5. Examine any available trend information 6. Apply triad decision matrix to data 7. Identify priorities and recommend actions Wet Weather Wet weather chemistry data (physical, chemical, and bacteriological measurements) from the mass loading stations (MLS) were compared to the Water Quality Objectives (WQO) shown in Table 3-11 to determine the constituents that are exceeded most often in the watershed. The tables are not inclusive of all analytical measurements that can be conducted, but represent the constituents that are most common to water quality monitoring. If other chemistry data are available, the appropriate standards or water quality objectives are identified. In general, water quality objectives are defined in the San Diego County Copermittee program as benchmarks for comparison to monitoring results and do not necessarily reflect regulatory compliance for municipal storm water discharges. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-33 MLS wet weather results were compared to water quality objectives found in the following sources: ♦ San Diego Basin Plan (September 8, 1994) ♦ California Toxics Rule (CTR) 40 CFR 131 – 65FR 31682, May 18, 2000 ♦ USEPA Multi-Sector General Permit (65FR 64746, October 30, 2002) ♦ California Department of Fish and Game In order to allow for comparison with exceedances at the dry weather station (DWS), for which different Action Levels are used, modifications were made to the WQOs for bacterial indicators. Wet weather results were compared against the dry weather action levels to determine exceedances in total and fecal coliforms and enterococci. The water quality objectives utilized are the same across all watersheds in San Diego County except for total dissolved solids and fecal coliform. Total dissolved solids objectives are applied by hydrologic area or hydrologic sub-area as noted in the 1994 Basin Plan (Table 3-11). Fecal coliform REC-2 standards are applied at Tecolote Creek, Chollas Creek, and Tijuana River, while REC-1 standards are used for all other watersheds as shown in Table 3-11 below. Table 3-11. Water Quality Objectives for Wet Weather Monitoring at Mass Loading Stations. Constituent Units WQO Source General / Physical / Organic Electrical Conductivity umhos/cm Oil And Grease mg/L 15 USEPA Multi-Sector General Permit pH pH Units 6.5-8.5 Basin Plan Bacteriological Enterococci MPN/100 mL Fecal Coliform MPN/100 mL 400/4,000 Basin Plan REC-1/REC-2 Total Coliform MPN/100 mL Wet Chemistry Ammonia As N mg/L Un-ionized Ammonia as N μg/L 25 (a) Basin Plan Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit Nitrate As N mg/L 10 Basin Plan Nitrite As N mg/L 1 Basin Plan Surfactants (MBAS) mg/L 0.5 Basin Plan Total Dissolved Solids mg/L 750 Basin Plan by watershed Total Kjeldahl Nitrogen mg/L Total Phosphorus mg/L 2 USEPA Multi-Sector General Permit Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit Turbidity NTU 20 Basin Plan Pesticides Chlorpyrifos μg/L 0.02 CA Dept. of Fish & Game Diazinon μg/L 0.08 CA Dept. of Fish & Game Malathion μg/L 0.43 CA Dept. of Fish & Game Hardness Total Hardness mg CaCO3/L Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-34 Table 3-11. Water Quality Objectives for Wet Weather Monitoring at Mass Loading Stations. Constituent Units WQO Source Total Metals Antimony mg/L 0.006 Basin Plan Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan Cadmium mg/L (b) 40 CFR 131 Calcium mg/L (b) Chromium mg/L (b) CTR (Cr VI) Copper mg/L (b) 40 CFR 131 Lead mg/L (b)/0.1 40 CFR 131 Magnesium mg/L 0.02 Nickel mg/L (b) 40 CFR 131/ Basin Plan Selenium mg/L 0.006 40 CFR 131 Zinc mg/L 0.34/0.05 40 CFR 131 Dissolved Metals Antimony mg/L (e) 40 CFR 131 Arsenic mg/L 0.34 (c) 40 CFR 131 Cadmium mg/L (b) 40 CFR 131 Chromium mg/L (b) 40 CFR 131 Copper mg/L (b) 40 CFR 131 Lead mg/L (b) 40 CFR 131 Nickel mg/L (b) 40 CFR 131 Selenium mg/L 0.2 (d) 40 CFR 131 Zinc mg/L (b) 40 CFR 131 (a) Water Quality Objective is for unionized ammonia which may be calculated from ammonia as nitrogen using pH, temperature and salinity. (b) Water Quality Objective for total and dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000. (c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000. (d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000. (e) USEPA has not published an aquatic life criterion value. Sources USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Siepmann and Finlayson 2000. Basin Plan, September 8, 1994. Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958. USEPA Federal Register Document 40 CFR Part 131, May 18, 2000. Toxicity testing at the MLS does not measure a COC. Toxicity is a test to determine if an analyte (chemical or other) or group of analytes is present in concentrations capable of causing toxicity in the selected species. Once an analyte(s) is identified as the source of the toxicity through the TIE/TRE steps of the method, then it is possible to define toxicity as having a high frequency of occurrence because it has been positively linked to the actual constituent of concern identified to be causing the toxicity. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-35 The results reported for the Copermittee monitoring program focus on the acute toxicity limit as the NOEC of 100% for the test sample. This limit will take into account any inherent variability in the test, yet still be protective of the watershed. The seven-day chronic effects are estimated using the NOEC for both survival and reproduction. This is the highest concentration tested in which there was no statistically significant effect on the survival or reproduction compared to the control response. Lower NOEC values equate to higher toxicity in the sample. Therefore, a concentration of less than 100% is considered to have some degree of toxic effect. The water quality objectives used in regional monitoring program are shown in Table 3-12. Table 3-12. Toxicity Water Quality Objectives for wet weather monitoring at Mass Loading Stations. Species/Test Units WQO Source1 Toxicity Ceriodaphnia 96-hr LC50 (%) 100 NPDES Order 2001-01; Appendix D-6 Ceriodaphnia 7-day survival NOEC (%) 100 NPDES Order 2001; Appendix D-6 Ceriodaphnia 7-day reproduction NOEC (%) 100 NPDES Order 2001; Appendix D-6 Hyalella 96-hr NOEC (%) 100 NPDES Order 2001; Appendix D-6 Selenastrum 96-hr NOEC (%) 100 NPDES Order 2001; Appendix D-6 (1) Modified from TUa to NOEC as noted in the text. Persistent toxicity is evident when more than 50% of the toxicity tests conducted to date for any given species at a specific site have a NOEC of less than 100%. The results of this determination are then combined with the high frequency constituents of concern (chemistry data) and benthic data in the Triad Decision Matrix to determine the actions to be taken. Dry Weather Dry weather action levels are established by the Copermittees to trigger investigations upstream of the sampling location and to eliminate illicit connections and illegal discharges (ICID). Dry weather action levels were initially established in 2002 and are updated on a yearly basis, as necessary. The WMA assessments compare wet and dry weather exceedances. In some cases, the wet weather water quality objectives are not comparable with dry weather action levels. For example, turbidity action levels in dry weather samples are evaluated using Best Professional Judgment; while in wet weather (at the MLS) the Basin Plan water quality objective of 20 NTU is used. In order to allow for direct comparison with exceedances at the MLS, when assessing dry and wet weather samples for turbidity at a watershed level the Basin Plan objective was used. See Table 3-13 for a summary of the dry weather action levels used to perform the data evaluation. Triad Assessment For each watershed, all three elements of the triad (chemistry, toxicity, and benthic community) are assessed. Chemistry data provide an indication of the pollutant load during a storm event and toxicity data an indication of the potential impacts to aquatic organisms during storm events. Dry weather chemistry data provides an indication of urban runoff pollutants. The benthic community data collected during stream bioassessment provides a more direct indication of the ecological health of the watershed in terms of insect/benthic community abundance and diversity. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-36 Table 3-13. Dry Weather Action Levels Constituent Action Level Note pH <6.5 or >9.0 Orthophosphate-P 2.0 mg/L Nitrate-N 10.0 mg/L Ammonia-N 1.0 mg/L Turbidity 20 NTU Used Basin Plan WQO instead of BPJ when comparing with MLS data Conductivity Best professional judgment MBAS 1.0 mg/L Oil and grease 15 mg/L Diazinon 0.5 ug/L Chlorpyrifos 0.5 ug/L Dissolved Cadmium CTR Dissolved Copper CTR Dissolved Lead CTR Dissolved Zinc CTR Used CTR table, 1-hour criteria. Action level is based on hardness. Where hardness data were not available, the average value for the watershed was substituted. Total Coliform 50,000 MPN/100 mL Fecal Coliform 20,000 MPN/100 mL Enterococcus 10,000 MPN/100 mL 2003 Action Levels defined by 95th percentile were applied at the MLS for comparison with DWS data. Basin Plan objectives are only available for Fecal coliform (REC-1 and REC-2) as shown in Table 3-11. The triad assessment does not consider fecal coliform and total dissolved solids for the purposes of triggering a decision or action. The bacteria parameters are not considered in the triad because they are not believed to influence toxicity responses in bioassay test organisms. Further, the REC-1 (water contact) and REC-2 (non-contact) WQOs for bacterial indicators are set for the protection of human health. Total dissolved solids are not considered since the water quality objectives for this COC as defined in the Basin Plan are set for municipal drinking water and do not necessarily reflect impacts to the ecology of the watersheds. However, fecal coliform and total dissolved solids data may be used to define high priority COC that lead to management actions even though they bypass the application of the triad decision matrix. Persistence in several indicators provides an indication of an ecological concern that triggers the need to conduct short-term actions, such as a TIE to identify the COCs in the watershed that may be responsible for storm water toxicity and/or benthic community degradation. Where long-term datasets are available, all the data are evaluated to identify persistent conditions. The majority of the mass loading stations are in their fourth year (2004-05) of monitoring and have data from 12 storm events available for the triad assessment. Persistence was determined for three elements of monitoring (chemistry, toxicity, and benthic community assemblage) using the definitions in Table 3-14. Table 3-14. Triad Definitions for San Diego Storm Water Monitoring Program. Triad Component Definition Persistent Exceedance of Water Quality Objectives A constituent of concern with a high frequency of occurrence based on wet and dry weather data exceedances compared to established list of benchmarks or action levels. Evidence of Persistent Toxicity More than 50% of the toxicity tests for any given species have a NOEC of less than 100%. Indication of Benthic Alteration IBI score indicates a substantially degraded community (very poor). Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-37 Once persistence is determined in each watershed, the determination of short-term actions, namely TIEs is made using the Tabular Decision Matrix, Table 3-15. Table 3-15. Tabular Decision Matrix – chemical, toxicity, and benthic assemblage data available (adapted from SMC Model Storm Water Monitoring Program, 2004). Chemistry Toxicity Benthic Alteration Example Conclusions Example Actions or Decisions 1. Persistent exceedance of water quality objectives (high frequency COC identified) Evidence of persistent toxicity Indications of alteration Strong evidence of pollution- induced degradation 1) Toxicity tests at higher dilutions to better quantify toxicity; Use TIE to identify contaminants of concern, based on TIE metric. 2) Evaluate/identify upstream source as a high priority. 2. No persistent exceedances of water quality objectives No evidence of persistent toxicity No indications of alteration No evidence of current pollution-induced degradation Potentially harmful pollutants not yet concentrated enough to cause visible impact 1) No immediate action necessary. 2) Conduct periodic broad scans for new and/or potentially harmful pollutants. 3. Persistent exceedance of water quality objectives (high frequency COC identified) No evidence of persistent toxicity No indications of alteration Contaminants are not bioavailable Test organisms not sensitive to problem pollutants 1) TIE would not provide useful information with no evidence of toxicity. 2) Continue monitoring for toxic and benthic impacts. Consider whether different or additional test organisms should be evaluated. 3) Initiate upstream source identification as a low priority. 4. No persistent exceedances of water quality objectives Evidence of persistent toxicity No indications of alteration Unmeasured contaminant(s) or conditions have the potential to cause degradation Pollutant causing toxicity at very low levels Synergistic effects of multiple chemicals at low levels causing toxicity 1) Recheck chemical analyses and evaluate detection limits relative to reported toxic levels. 2) Verify toxicity test results; Consider additional advanced chemical analyses. 3) Toxicity tests at higher dilutions to better quantify toxicity: Use TIE to identify contaminants of concern, based on TIE metric; Evaluate/investigate upstream source as a medium priority. 5. No persistent exceedances of water quality objectives No evidence of persistent toxicity Indications of alteration Alteration may be due to physical impacts, not toxic contamination Test organisms not sensitive to problem pollutants Synergistic effects of multiple chemicals at low levels causing toxicity 1) No action necessary based on toxic chemicals. 2) Consider whether different or additional test organisms should be evaluated. 3) Consider potential role of physical habitat disturbance. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-38 Table 3-15. Tabular Decision Matrix – chemical, toxicity, and benthic assemblage data available (adapted from SMC Model Storm Water Monitoring Program, 2004). Chemistry Toxicity Benthic Alteration Example Conclusions Example Actions or Decisions 6. Persistent exceedance of water quality objectives high frequency COC identified) Evidence of persistent toxicity No indications of alteration Toxic contaminants are bioavailable, but in situ effects are not demonstrable Benthic analysis not sensitive enough to detect impact Potentially harmful pollutants not yet concentrated enough to change community 1) Determine if chemical and toxicity tests indicate persistent degradation. 2) Recheck benthic analyses; consider additional data analyses. 3) Toxicity tests at higher dilutions to better quantify toxicity: • If recheck indicates benthic alteration, perform TIE to identify contaminants of concern, based on TIE metric. Evaluate/investigate upstream source as a high priority. • If recheck shows no effect, use TIE to identify contaminants of concern, based on TIE metric. Evaluate/investigate upstream source identification as a medium priority. 7. No persistent exceedances of water quality objectives Evidence of persistent toxicity Indications of alteration Unmeasured toxic contaminants are causing degradation Pollutant causing toxicity at very low levels Synergistic effects of multiple chemicals at low levels causing toxicity Benthic impact due to habitat disturbance, not toxicity 1) Recheck chemical analyses and consider additional advanced analyses. 2) Toxicity tests at higher dilutions to better quantify toxicity. Use TIE to identify contaminants of concern, based on TIE metric. 3) Evaluate/investigate upstream source identification as a high priority. 4) Consider potential role of physical habitat disturbance. 8. Persistent exceedances of water quality objectives (high frequency COC identified) No evidence of persistent toxicity Indications of alteration Test organisms not sensitive to problem pollutants Benthic impact due to habitat disturbance, not toxicity 1) TIE would not provide useful information with no evidence of toxicity. 2) Evaluate/investigate upstream source identification as a high priority. 3) Consider whether different or additional test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. Establishing Frequency of Occurrence The monitoring results (including all monitoring years’ data) are examined to establish if percentages data exceed water quality objectives or action levels, rank bioassessment results, and prioritize toxicity results. The matrix of findings is developed for each watershed (Table 3-16). The matrix includes a number of observations that exceed water quality objectives. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-39 Table 3-16. Matrix of Findings. SAN LUIS REY RIVER MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters pH 0 0 1 33 0 0 0 0 1 8 1 3.5 - - BOD 0 0 0 0 1 33 0 0 1 8 NA NA - - Total Dissolved Solids 3 100 3 100 3 100 3 100 12 100 NA NA ♦♦♦ 1 Total Suspended Solids 0 0 1 33 0 0 1 33 2 17 NA NA - - Turbidity 0 0 1 33 0 0 2 67 3 25 4 21 ♦ 8 Nutrients Ammonia 0 0 0 0 0 0 0 0 0 0 6 21 ♦ 8 Nitrate as N 0 0 0 0 0 0 0 0 0 0 5 22 ♦ 8 Bacteriological Total Coliform 0 0 0 0 0 0 1 33 1 8 7 27 ♦ 8 Fecal Coliform 0 0 1 33 1 33 3 100 5 42 1 4 ♦ 9 Enterococcus 0 0 1 33 0 0 2 67 3 25 2 8 ♦ 9 Pesticides Diazinon 1 33 0 0 0 0 0 0 1 8 0 0 - - Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 7- day reproduction 1 33 0 0 1 33 0 0 2 17 NA NA No Selenastrum 96- hour 0 0 0 0 1 33 0 0 1 8 NA NA No Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? San Luis Rey River, at Benet Rd. (DS) Very Poor Very Poor Very Poor Very Poor Very Poor NA San Luis Rey River, Mission Rd. Very Poor Very Poor Very Poor Very Poor Very Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS The COC Frequency of Occurrence ranking of “high”, “medium”, or “low” is established using the 2002- 03 interim criteria (Table 3-17). This was the same criteria used during the 2003-2004 monitoring season. The interim criteria take into account the exceedances at the MLS, DWS and coastal outfalls; and classify each COC as high, medium or low frequency of occurrence in the watershed. The classification of COC can change from year to year in response to the changes in the levels of the pollutants. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-40 Table 3-17. Interim Criteria for Evaluating Mass Loading and Dry Weather Station Data. COC Frequency of Occurrence Criterion No. Definition 1 Mass loading station tests results exceed WQO in greater or equal to 80% of samples. 2 Six of the last consecutive storm samples at the MLS exceed WQO. 3 Less than 80% and greater than or equal to 50% of the MLS samples exceed WQO and at least one DWS exceedance in the past year. High ♦♦♦ 4 Less than 80% and greater than or equal to 50% of the MLS samples exceed WQO and a significant increasing trend is found. 5 Less than 80% and greater than or equal to 50% of the MLS samples exceed WQO and no exceedances or data available for DWS in the past year. 6 Less than 80% and greater than or equal to 50% of the MLS samples exceed WQO and one or more exceedances found in last 2 years of monitoring at the MLS (generally applies to historical datasets). Medium ♦♦ 7 Greater than 50% of the DWS samples have exceedances in the past year. 8 DWS exceedances in 10 to 50% of the samples in the past year. 9 MLS exceedances found in 25% to less than or equal to 50% of the samples and at least one exceedances found in last 2 years at the MLS (with or without DWS exceedances in the past year). Low ♦ 10 Greater than 50% of the MLS samples have exceedances and no exceedances in the last 2 years at the MLS. Coastal Program 11 Persistent exceedances (greater or equal to 80% of samples). Add one to bacteria determination (up to three maximum). Note: Best professional judgment applies when unique situations arise (fewer samples at a site; sewage spills) and for toxicity once it is linked to a specific COC. DWS data were given less weight in the determination of watershed COC due to factors that include: 1. The dry weather monitoring program’s main focus is to identify illicit connections and illegal discharges (ICID). Sample stations may not be representative of overall urban runoff quality since they include samples of ponded water. 2. Dry weather monitoring parameters are a subset of MLS monitoring parameters. 3. DWS may be located in the MS4 upstream of BMPs (detention basins, etc.) and samples may not be representative of urban runoff entering the receiving water. For this evaluation, dry weather stations that only have field test kit results are not used in the assessment of COC. Only DWS monitored using laboratory analysis from grab samples including concurrent field test results are considered for comparison with MLS exceedances of water quality objectives. Only DWS located upstream of the MLS are taken into account when applying the interim COC criteria. Lastly, only DWS samples collected during routine monitoring and not as part of the ICID investigation phase of the program are used. The majority of the 2005 dry weather data used for the assessment represented routine site visits. If the number of DWS sampled was small, best professional judgment was used when applying the interim COC criteria. For example, if only three samples were collected and one exceedance was observed, then the 33% exceedance frequency may not be representative of watershed conditions. Benchmarks for bacterial levels are judged differently in the MLS and DWS. The MLS water quality objective for fecal coliform was derived from the Basin Plan (REC-1 and REC-2) while DWS levels are Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-41 compared to Copermittee defined action levels for all three bacterial indicators (total and fecal coliform and enterococcus). In order to compare the two datasets, the DWS action levels are applied to the MLS total coliform, fecal coliform, and enterococcus data. Otherwise, identification of bacterial indicators as potential COCs in the watershed between these two different data sets would not have been feasible. Ratio to Water Quality Objectives Ratios to WQO were determined for constituents that have most frequently exceeded WQO across all watersheds for each storm event in 2004-2005. Mean ratios to WQO were determined for each constituent from 2001-2002, 2002-2003 and 2003-2004. Santa Margarita River was not sampled during 2004-2005, therefore only the mean ratios to WQO from 2001-2002, 2002-2003 and 2003-2004 are presented. The ratio to WQO for each constituent was determined by dividing the value by the WQO for each storm event. The mean ratio is the mean of all ratio to WQO for each constituent from 2001- 2002, 2002-2003 and 2003-2004. Toxicity ratios were determined by dividing the value (% survival) into 100 and then subtracting one. For example, the ratio to WQO of an organism with 50% survival is 1 [(100/50)-1=1]. 3.4.2 Long-Term Effectiveness Assessment–Water Quality Priority Rating Methodology The following methodology which was developed in the Baseline Long-Term Effectiveness Assessment (BLTEA) report (WESTON, MOE, & LWA 2005) was used to also establish a process to assess long-term water quality trends and relate them to the overall effectiveness of the management program. Water quality characterization and prioritization is achieved through the Water Quality Priority Rating process conducted for each of the constituent/stressor groups on a sub-watershed and watershed basis. These constituent groups include: • Heavy Metals • Organics • Oil and Grease • Sediment (TDS, SS, Turbidity) • Pesticides • Nutrients • Gross Pollutants • Bacteria/Pathogens The Water Quality Priority Rating for these eight constituent groups is determined using the available data set. The dry weather data set provides results on a sub-watershed basis. However, this data set is limited to 2 years of monitoring results and has focused on sampling of storm sewers. In order to augment the current data set, the wet weather data from the MLS was used to project these results up into the watershed as discussed below. The wet weather data set is more robust in that data has been collected at some stations since 1993. The assessment of the water quality on a sub-watershed basis for the constituent groups has also been supplemented using the ABLM results for sediment analysis. Therefore, the water quality rating on a sub-watershed and watershed basis for the eight constituent groups is based on results from the dry weather program, the wet weather results from the MLS, and the sediment results from the ABLM program. The additional evaluated stressor groups include Benthic Alteration and Toxicity. These last two groups are evaluated separately as they represent a stressor group that may be impacted by multiple Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-42 constituents and/or stressors, as compared to the other groups that represent specific constituents. The basis for the water quality ratings for the Toxicity stressor group include the toxicity testing results from the wet weather sampling at the MLS and the sediment sampling conducted as part of the ABLM program. These results were projected up into the watershed as discussed below to provide a rating on a sub-watershed basis. There is no dry weather toxicity data that has been conducted on a sub- watershed basis. The Benthic Alteration stressor group rating is based on the results of the regional bioassessment conducted during wet weather conditions, and the ABLM benthic community structure results conducted on sediment samples. These data are then used to develop the prioritization ratings that are based on a score of 0 – 3. From the numerical score, a prioritization rating is then assigned. The highest priority rating is A, followed by a rating of B, C, and D. D therefore represents a low priority rating. The following six steps outline the method in developing the Water Quality Priority Rating for the eight constituent groups listed above. These steps are summarized in Figure 3-3. Figure 3-3. Water Quality Priority Rating Methodology. Step 1. 303d List Each constituent group was evaluated to determine whether or not there is a 303d listing in any of the sub-watersheds within a WMA. If there was a 303d listing, then a Y (for yes) was placed in the cell, otherwise an N (for no) was placed in the cell. This was a conservative assumption since the entire sub- watershed was designated as a yes value, even if the 303d listing only applied to a small, specific water body within that sub-watershed. If a sub-watershed has a section that is 303d listed for that constituent group, then that sub-watershed automatically receives a score of 3. This use of the 303d list to override the water quality results was used in this process not to question the actual data, but to identify a high priority to assess trends in water quality within this sub-watershed and the need to identify high loading potential sources based on the overall threat to water quality assigned to the watershed and sources located within the sub-watershed. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-43 Step 2. Dry Weather Data Eight Constituent Groups - The data currently available on a sub-watershed level is the dry weather data collected by the Copermittees throughout the county. The dry weather scores were determined by estimating the percentage of exceedances over constituent specific water quality objectives (WQO). Each sub-watershed was assigned a score of 0, 1, 2, or 3 for each of the constituent groups. These determinations were based on the following scale summarized in Table 3-18: Table 3-18. Summary of Water Quality Exceedance Scale. Score Exceedance Scale Minimum Number of Data Points Needed Alternative Score if Minimum Data Requirements Not Met 3 Exceedance > 50% 3 2 2 25%<Exceedance<50% 3 1 1 10%<Exceedance<25% 3 0 0 Exceedance < 10% 3 0 Blank No Data 0 N/A Benthic Alterations and Toxicity - The dry weather column is not included on the Benthic Alterations group at this time. Should bioassessment be conducted in dry weather for sites that have sufficient dry weather flow, this category may be added in the future. The dry weather column is included for the Stressor Group, Toxicity, as dry weather sampling up into the watersheds may be conducted during the next permit cycle as part of the triad sampling strategy. Currently no dry weather toxicity data exist, therefore this column is left blank for this current assessment. When data becomes available, the scoring methodology will follow that as described below under the wet weather toxicity results. Step 3. Wet Weather Score Eight Constituent Groups - Wet weather data is currently available at the mass loading stations (MLS), which are located near the downstream reaches of watersheds in the County. Due to the placement of the MLS, data collected represents the monitored portion of the watershed. Because there is currently no wet weather data on a sub-watershed basis, the MLS data was projected up into the watershed to develop the score as discussed below. In the future, should wet weather data be collected on a sub- watershed basis, this scoring will utilize the sub-watershed specific data in combination with the MLS data. For the current data set, each WMA was first assigned a 0, 1, 2, or 3 score based on the wet weather MLS data, using the same rating scale described above for dry weather data (See Table 3-18). The MLS score was then used to assign a 0, 1, 2, or 3 to each of the sub-watersheds based on the following criteria as presented in Table 3-19: Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-44 Table 3-19. Summary of MLS -Wet Weather Water Quality Exceedance Scale. WMA MLS Score Up-Stream Sub-Watershed Score Sub-Watershed Score Where MLS Located 3 2 3 2 2 2 1 1 1 0 0 0 Blank No Data 0 There are a few exceptions to the methodology described above. Some of the WMAs group together a number of watersheds (Carlsbad, San Diego Bay). The MLS data collected at the downstream end of one watershed doesn’t necessarily reflect conditions in an adjacent watershed. In those instances where there is no MLS station anywhere downstream of a sub-watershed, the corresponding sub-watershed cells were left blank. Benthic Alterations - For the Benthic Alterations, the wet weather score is based on the available data from bioassessments conducted at or near the MLS and within a sub-watershed. The benthic alteration evaluation is presented separately from the chemical constituent groups, because this category reflects an overall assessment of the health of the receiving water body with regard to the benthic population. It is not incorporated into the overall wet weather score because impacts to the benthic community can be from various sources, and therefore are not constituent specific. It provides additional data on the overall water quality of the receiving waters. Table 3-20 provides a summary of the scoring criteria for wet weather bioassessment results: Table 3-20. Summary of Wet Weather Benthic Alterations Scores. IBI Score Score within Sub-Watershed Where Bioassessment Station Located Up-stream Sub-Watershed Score Poor to Very Poor 3 2 Poor to Fair 2 2 Fair 1 1 Good to Very Good 0 0 Blank No Data 0 Toxicity Group - For this group, the wet weather score is based on currently available toxicity results from the mass loading stations (MLS), which are located near the downstream reaches of watersheds in the county. Due to the placement of the MLS, data collected represents the monitored portion of the watershed. Toxicity exceedances were calculated by comparing toxic units, which are based on the median lethal concentration (LC50) and the No Observed Effect Concentration (NOEC), to an established water quality objective. The same criteria as summarized in Table 3-18 are used for the toxicity group based on the wet weather toxicity MLS data. The projection of MLS data to up-stream sub-watersheds as shown on Table 3-19 is also used. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-45 Step 4. Sediment Score The last data set used in this analysis is the ABLM data that is used to score the sediment category under each constituent group. As with the wet weather data, the current data set does not include sediment analysis on a sub-watershed basis. Therefore, the rating for sediment utilizes the ABLM results and projects these scores to the sub-watershed up-stream of where the sediment has been evaluated. Sediment quality in the lagoons is therefore used to develop the constituent priorities for the sub- watershed because impacted sediments are transported from throughout the watershed to the estuaries. As more sub-watershed specific sediment data is available, the score can be modified to reflect these data. ABLM results were compared against established effects range low (ERL) concentrations and effects range medium (ERM) concentrations. The ERL represents the concentration below which adverse biological effects are rarely observed, and the ERM represents the concentration above which adverse biological effects are more frequently observed. ABLM data were used to assign each constituent group with a number from 0 – 3, based on the criteria presented in Table 3-21: Table 3-21. Summary of Sediment Scoring Criteria. Scoring Criteria For Sediment Up-stream Sub- Watershed Score Concentration > ERM 3 ERL<Concentration< ERM 2 Data Inconclusive 1 Benthic Alternations Group – For this group the ABLM benthic community structure results were used. These results are presented as relative rankings between the coastal embayments monitored. For the purposes of this analysis, the following scale as shown on Table 3-22 was used to score the Benthic Alteration category: Table 3-22. Summary of ABLM Scoring Criteria. Score AMLM Scoring Criteria 3 Relative Ranking 0-3 2 Relative Ranking 4-6 1 Relative Ranking 7-9 0 Relative Ranking 10-12 Toxicity Group – For this group the ABLM toxicity results were rated using the criteria presented in Table 3-23: Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-46 Table 3-23. Summary of Toxicity Scoring Criteria. Score Toxicity Scoring Criteria 3 % Survival <40 2 40 < % Survival < 70 1 % Survival >70 0 % Survival not significantly different from control The ABLM score was then used to assign a 0, 1, 2, or 3 to each of the sub-watersheds based on the criteria presented in Table 3-19 for projecting the score up-stream into the watershed. Similar to what was described for the MLS data, there are a few exceptions to the methodology described above. In particular, the Carlsbad WMA constitutes a group of watersheds. The ABLM data collected in an embayment of one watershed doesn’t necessarily reflect conditions in an adjacent watershed. In those instances where there was no ABLM performed or a certain constituent wasn’t monitored for, the cell was left blank. Step 5. Sub-Watershed Scoring Once all of the data sets were scored, a total constituent group score for each constituent group and each sub-watershed was calculated. This score is a value from 0 to 3 and was calculated using the following method: • If there was a Y (yes) for the 303d listing, then that sub-watershed automatically received a score of 3 for that constituent, over-riding the scores for the dry weather, wet weather, and sediment data as discussed under Step 1. • If there was an N (no) for the 303d listing, then the sub-watershed score was calculated by taking the average of the dry weather, wet weather, and sediment data sets. Step 6. Water Quality Priority Rating The final step in this process was to determine the Water Quality Priority Rating for each constituent group within a WMA. In order to account for greater loading from larger sub-watersheds compared to smaller ones, the Priority Rating was calculated by using an area weighted average of the scores from each of the sub-watersheds. This approach is different from the sub-watershed score which used the average of the 303d, dry weather, wet weather and sediment scores. The following equation illustrates this procedure: Priority Rating = % Area 1 * Sub-watershed 1 Score + % Area 2 * Sub-watershed 2 Score The resulting ratings were used to assign the Water Quality Priority Rating or Level of each constituent/stressor group using the following scale: • Priority Level A = Rating 2.25 – 3.00 – Highest Priority Rating • Priority Level B = Rating 1.50 – 2.24 Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-47 • Priority Level C = Rating 0.75 – 1.49 • Priority Level D = Rating 0.00 – 0.74 – Lowest Priority Rating Constituent Group - Metals Step 6: Priority Rating Area 303d Dry Weather Wet Weather Sediment Score Sub-watershed 1 75% N 2 3 1 2 Sub-watershed 2 25% Y 0 2 1 3 MLS Results 3 ABLM Results 1 Rating 0.75*2 + 0.25*3 = 2.25 Priority Level A The exceptions to this procedure included Carlsbad WMA and San Diego Bay WMA in which no data existed for several sub-watersheds, and therefore no score was determined for these sub-watersheds. For these cases, the watershed priority rating was based on the weighted average using the total areas of only these sub-watersheds for which a score was determined. The percent of total area used in the weighted average was therefore based on the total area of the rated sub-watersheds for which data was available, instead of using the total area of the WMA. The other exceptions included Tijuana and Santa Margarita WMA. The total area used in the weighted average was based on the areas of the sub- watersheds within the County instead of the total area of the WMA. 3.5 Watershed Assessment Statistical Methods 3.5.1 Relationships and Trends Relationships between toxicity and COCs were examined by MLS to determine which COC may have an effect on toxicity. A chi-square non-parametric test was used for this assessment. Each COC was compared to the appropriate water quality objective and scored as to whether the concentration was above or below the objective (1=above, 0=below). Likewise, the toxicity results for each of the five toxicity tests was also scored (1=toxicity, 0=no toxicity). The chi-square test counts the number of observations in each combination of scores (e.g., 1,1=toxicity and COC above WQO) and compares the resulting pattern in a 2X2 table to what would be normally expected. Significance was set at p<0.05 (or 95% confidence), with only 12 observations, results with more than one observation in a mixed combination (1,0 or 0,1) were not significant. In addition, long-term trends in the data were examined by regression analysis to determine whether an observed upward or downward tendency of the data was statistically significant (significance was set at p<0.05). R2 values are indicators of how well the regression model fits the data, i.e., larger values show a closer fit to the regression line than smaller values. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-48 3.6 Cross Watershed Statistical Methods The goals of the cross-watershed comparison are to assess all information from each watershed together to evaluate and rank watersheds across the region. Assessing all data from the region together also provides the ability to evaluate relationships among COC and between toxicity effects and COC. 3.6.1 COC Comparisons The statistical tools used for the cross watershed comparison included scatterplot analysis, regression analysis, analysis of variance (ANOVA), and multivariate cluster analysis. Scatterplots provide a COC based comparison among watersheds and monitoring years. The ANOVA was used to determine statistical differences between the watersheds for the year as a whole (storms were used for replication), and cluster analysis was used to identify mass loading stations and sampling dates with similar COC loadings. Scatterplots provide a visual representation of the relative concentrations of COC between stations and storm events. Scatterplots are simple plots of concentrations of COC plotted on the y-axis against the mass loading station identified on the x-axis. Each COC and toxicity test is represented by its own scatterplot with all sampling dates for the past three monitoring years plotted on a single graph. Where historical data for the longer-term mass loading stations (Agua Hedionda Creek, Tecolote Creek, and Chollas Creek) are available, trend data plots are included. The data shown in the trend data plots were tested by regression analysis to determine significant trends. When an upward or downward trend was statistically significant (p<0.05) the trend line is shown on the data plot. Non-detectable results were plotted at the detection limit. Also, when COC concentrations during separate storm events were equivalent, the scatterplot appears to have only one point at that concentration because the points are co-located. All COC were monitored at mass loading stations during three storms each year (with the exception of Santa Margarita River) and all points are included in scatterplots. ANOVA was used to determine differences between MLS for the COC. The term analysis of variance is sometimes a source of confusion. In spite of its name, ANOVA is concerned with differences between means of groups, not differences between variances. The analysis uses variances to detect whether the means are different. The ANOVA determines the variation (variance) within the groups that are being compared (e.g., monitoring stations), then compares that variation to the differences between the groups, taking into account how many subjects there are in the groups. If the observed differences between the means of groups are larger than those expected by chance relative to the underlying variance, statistical significance is achieved. For this report, each of the COC that were observed in any sample above the MDL was tested by ANOVA. Because this statistical analysis needs to calculate a variance for each group to be compared, the COC with results below the detection limit at a station were handled as suggested in USEPA (1998). If only one sample was below the detection limit, one-half the detection limit was used. If more than one sample was below the detection limit, each of the values was set so that the mean of all the values would be one-half the detection limit. For example, if the detection limit was 0.6 and there were two values below the detection limit, one would be set to 0.15 and the other would be set to 0.45 so that the mean of the two values was 0.3 (one-half the detection limit). The bacteriological measures were log10 transformed for this analysis. Multivariate cluster analysis was applied to the COC and the toxicity endpoints (in terms of NOEC values) for each MLS and sampling time. This approach groups the station/times by the commonality of the COC concentrations found at each one. Likewise, it groups the COC according to similar loadings at Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-49 stations. Prior to the analysis the bacteriological measures were log10 transformed and the data for each COC was standardized by the overall mean value for each COC. 3.6.2 Relationships between Toxicity and COC The relationship between toxicity and constituents of concern (COC) has been evaluated by two methods. The first method presented below uses a multiple regression model to correlate changes in toxicity to changes in COC levels in the water. This method groups data from all watersheds, is useful in providing general trends across the county, and evaluating the effects of several COC at once. Sometimes thresholds of chemical concentrations are involved with toxicity whereby the organisms do not respond negatively until a certain chemical level is reached. Concentrations of COC above a specific threshold may no longer illicit a linear response in organism toxicity. Consequently, thresholds detract from the regression model. Therefore, a second method, threshold analysis, was used to clarify relationships following the regression analyses using the COC that were significant components of the final multiple regressions. The threshold analysis uses COC levels reported to be toxic in the literature where available and compares them to COC levels in the storm water samples. 3.6.2.1 Multiple Regression Analysis of Toxicity Data Multiple regression was the statistical tool used to look for relationships between toxicity results and the physical, chemical, and biological COC across all watersheds. This type of statistical analysis looks for the best relationship between the response variable (i.e., toxicity units for each endpoint) and the regressor variables (COC). To best fit a multiple regression model, the number of observations must be larger than the number of regressor variables. Because the number of COC was greater than the number of samples, it was first necessary to reduce the number of COC used in the analysis. To do this reduction, a principal component analyses (PCA) was performed on the COC. Two PCA analyses were run, the first for metal constituents and the second for the physical and organic results (excluding bacteria and pesticides). The PCA creates factor loadings along multiple axes that define (or explain) the variance in the data and identifies the contribution of each constituent to each axis. The resultant axes that accounted for a significant portion of the variance were run as regressors in addition to bacteria and pesticide measurements for each toxicity endpoint. The best-fit regression was selected for each endpoint by running a backward regression. This type of multiple regression starts with all regressors and eliminates them step-by-step according to their contribution to the model (least significant are dropped first) until all regressors remaining are significant. The adjusted R2 values (adjusted for the number of observations and number of regressors) tend to stabilize when an adequate number of regressors remain in the model and are therefore used to determine the best model for the regression. When one of the PCA axes was retained as a significant regressor in the model, a second regression was run with the individual COC that were weighted at least 0.75 on the axis to further refine the analysis. Due to differences in detection limits for pesticides and dilutions for bacteria analyses for the data collected at Santa Margarita River, this site was excluded from these analyses. Additionally, another multiple regression was run combining the results from 2001-02, 2002-03, and 2003-04. With the additional observations, it was not necessary to screen the regressor variables and all COC that were measured in both years were included in the analyses. Methods SECTION 3 2004-2005 Urban Runoff Monitoring Report 3-50 3.6.2.2 Threshold Analyses Threshold values from literature, the total maximum daily load (TMDL) Study in Chollas Creek (MEC 2002), and other studies not yet published (personal communication with Jack Word) were assigned to COC retained in the final regressions of each toxic response test (e.g., Ceriodaphnia chronic test for survival). Where threshold values were not available, “best-fit” values (those that gave the best match to the observed toxicity results) were selected. Values were available for Diazinon, nickel, lead, zinc, nitrate, and conductivity. Resources The EPAs “Ecotox” database (www.epa.gov/ecotox) provides toxicity data by species and chemical, which is collected from a large number of independent studies. This resource also provides information on test duration, endpoints observed, as well as other parameters. Toxicity values for nitrate, metals, and all three test species were collected from this resource. The Handbook of Environmental Data on Organic Chemicals (Vershueren 1983) provides data on air and water pollution factors, bioconcentration and toxicity for a variety of organic chemicals, including pesticides. Toxicity data are provided by species and endpoint. Toxicity values for Diazinon, Chlorpyrifos, and Malathion for species related to Ceriodaphnia dubia and Hyalella azteca were collected from this resource. Other resources included the Chollas Creek TMDL Study conducted over several storm seasons in Chollas Creek (MEC 2002) and private client studies not yet published conducted by Weston (personal communication, Jack Word). Despite the usefulness of these resources, they have limitations. Toxicity values are not always provided for the test durations used in this storm water toxicity study. When using a value from a longer test period (say a 21-day test), the value will likely be a conservative estimate of what level would actually cause toxicity in a 7-day test. Data are also not provided for all COC or it is possible that the data provided is for a related species to the test species used in this study, which will most likely have a different sensitivity to the toxicants than the test species selected for this study. Criteria used in the selection of the literature value reported in this study include the test period (close to that used for the current study), the endpoint measured (one that was measured in this study [e.g.: no behavioral endpoints]), the test species (either the test species used in this study or the one most closely related to it for which there is a value available), and the value itself (the lowest value reported). These resources do not provide toxicity data of physical parameters (e.g., total dissolved solids, hardness, turbidity) to the test species. For the relationship between physical parameters and toxicity it is best to rely upon the regression analysis. These resources also do not provide information on possible interactions between chemicals or the interactions between chemicals and physical parameters. The statistical testing procedure is used to establish a two-by-two matrix with one column of “less than the threshold” and the second column of “greater or equal to the threshold” and with one row of “no observed effect” and a second row of “effect observed”. Fisher’s Exact Test (2-tail) was used to establish the exact probability of the table outcome by chance. A small probability (<0.05) was used to determine if the assigned threshold values were significant in explaining the outcomes of the toxicity tests. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-1 4.0 SANTA MARGARITA RIVER WMA 4.1 Monitoring Site Descriptions The Santa Margarita River watershed management area includes the Santa Margarita watershed (HU 902.00). The Santa Margarita watershed is the second largest in the San Diego hydrologic region. It covers over 475,459 acres, with the majority of the watershed lying in Riverside County and just 26.6% in San Diego County (Figure 4-1). The watershed is made up of the following nine hydrologic areas: Ysidora, De Luz, Murrieta, Auld, Pechanga, Wilson, Cave Rocks, Aguanga, and Oak Grove. Major water bodies include the Santa Margarita River, Temecula Creek, Murrieta Creek, Santa Margarita Lagoon, Vail Lake, Lake O'Neill, Skinner Reservoir, and Diamond Valley Lake Reservoir. The Santa Margarita River is the least disturbed river system south of Santa Barbara County, and provides habitat for some of the largest remaining populations of several bird species. There are nine dams located in the watershed with 92% of the river miles categorized as free flowing. Lake O'Neill is not located in the river channel but does receive much of its water from seasonal river diversions (Coastal Conservancy 2001). Jurisdiction in the watershed is dominated by Riverside County (73.4%), with the remaining areas lying in unincorporated San Diego County and only 98 acres falling under the City of Oceanside. The southwestern portion of the watershed is dominated by Camp Pendleton Naval Reservation and Marine Corps Base. Military ownership makes up 8% of the watershed. This has kept the lower river and estuary from being developed and therefore, this region supports a variety of valuable habitats and other beneficial uses (Table 4-1). Table 4-1. Beneficial uses within the Santa Margarita watershed. Beneficial Uses Inland Surface Waters Coastal Waters Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z z z Agricultural Supply z z z Industrial Service Supply z z z Industrial Process Supply z z z Ground Water Recharge O z Navigation Contact Water Recreation z z z1 Non-Contact Water Recreation z z z Commercial and Sport Fishing Warm Freshwater Habitat z z Cold Freshwater Habitat z z Biological Habitats of Special Significance Estuarine Habitat z Wildlife Habitat z z z Rare, Threatened, or Endangered Species z z z Marine Habitat z Migration of Aquatic Organisms z Shellfish Harvesting Aquaculture Spawning, Reproduction and/or Early Development z = Existing; O = Potential 1 Shore and boat fishing only. Other REC1 uses prohibited. Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-2 Figure 4-1. Santa Margarita River Watershed Management Area. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-3 The upper portion of the watershed in Riverside County is under continued development. Major impacts to the watershed include surface and groundwater quality degradation, habitat loss, invasive species, and channel bed erosion. Constituents of concern are nitrate (surface and groundwater), sediment, coliform bacteria, and TDS in groundwater. Sources of these contaminants include agriculture, livestock and domestic animals, septic systems, use of recycled water, and urban runoff (San Diego County 2001). Currently there are five water bodies from this watershed listed on the SWRCB 2002 303(d) list (Table 4-2). The principal aquifer in the watershed is the Santa Margarita Basin. Annual precipitation for the portion of the watershed within the San Diego area ranges from 10.5 inches in the coastal areas to more than 16.5 inches in the eastern portion of the watershed (Figure 4-1). Table 4-2. Water bodies on the SWRCB 303(d) list in the Santa Margarita watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor Santa Margarita Lagoon Lower Ysidora 902.11 Eutrophic Rainbow Creek Gavilan 902.22 Nitrogen, Phosphorus Upper Santa Margarita River Gavilan 902.22 Phosphorus Sandia Creek Gavilan 902.22 TDS Murrieta Creek Wolf 902.52 Phosphorus Source: SWRCB 2003 The Santa Margarita River (SMR) mass loading station is within this watershed management area and is located on Camp Pendleton, north of Vandegrift Boulevard, under the Basilone Road Bridge. The Santa Margarita River is a natural channel at the sampling point. The contributing runoff area within San Diego County covers over 121,400 acres, which is approximately 26% of the total watershed area. The primary land use within the contributing runoff area is undeveloped (64%). Stream Bioassessment sampling in the Santa Margarita River WMA included several reference sites in Sandia and De Luz Creeks, as well as urban affected monitoring sites in the Santa Margarita River proper. All of the monitoring reaches in the upper watershed areas north of the city of Fallbrook have good year-round flow, relatively high gradients, and high quality in- stream habitats with stable cobble and boulder substrates. In the lower reaches of the River in Camp Pendleton, the gradient levels off and the primary substrate component is coarse unconsolidated sand with banks that support dense riparian vegetation. The Santa Margarita River flows into the Santa Margarita River Estuary before it enters the ocean. The Estuary is located in the southwestern corner of Camp Pendleton Marine Corps Base, approximately one mile north of the City of Oceanside. The Estuary encompasses approximately 192 acres of wetland habitat, the majority of which is designated as salt pan and salt marsh habitat (Coastal Conservancy 2000). The Santa Margarita River is the primary source of fresh water to the Estuary, but runoff and groundwater seepage also contribute fresh water to the area. The Estuary is open to the ocean intermittently through a series of narrow channels, but tidal influence is constrained by rock jetties at Interstate 5 and railroad crossings. Secondarily treated sewage was discharged to the Estuary from the 1940s through the 1970s and the salt flats have been used for military training exercises in the past. Currently, the Estuary is listed as impaired for eutrophic conditions on the SWRCB’s 2002 303(d) list and Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-4 has been since 1998 (Table 4-2). Other potential environmental pressures on the Estuary include invasive exotic vegetation, development in the upper watershed, and increased sedimentation. The Estuary consists of a central portion that is approximately 4,000 feet long by 1,500 feet wide at its widest point and a smaller arm that extends to the south. Three sites in the Santa Margarita River Estuary were sampled during the Ambient Bay and Lagoon Monitoring Program. Two were located in the upper portion of the Estuary between Interstate 5 and the ocean and one was located in the southern portion of the Estuary closer to the mouth (Figure 4-1). Oceanside Harbor is also located in the Santa Margarita River WMA. Oceanside Harbor was unique among the sites monitored in the ABLM Program because it is the only site that is not hydrologically connected to a watershed and thus has no major fresh water inputs. The Harbor has three main regions: an inner harbor, which contains all of the boat slips and boating facilities, a middle harbor, adjacent to the mouth of the inner harbor, and an outer harbor that parallels the rip rap breakwater. These natural features were used to delineate the three strata for the ABLM sampling (Figure 4-1). Connected to Oceanside Harbor to the north is another large area known as Del Mar Boat Basin, located on Camp Pendleton Marine Base. Access to this area was restricted and no samples were taken in Del Mar Boat Basin. The characteristics of the inner harbor are distinctly different from those in the middle and outer harbor. The inner harbor is relatively shallow with limited flushing due to tidal restrictions at its mouth. The middle and outer harbor areas are deeper, particularly near the harbor entrance and tidal exchange is much greater than that in the inner harbor. The three sites selected for assessment in the ABLM program were located in the inner harbor due to the fine grain size and high TOC levels in this area. 4.2 Storm Water Monitoring Summary 4.2.1 2004/2005 Results The Navy Public Works Center did not perform monitoring on the Santa Margarita River during the 2004-2005 season due to sampling equipment being lost in flooding during the first rain event. The Navy indicated that they would not sample during the remainder of the 2004-2005 wet-season. This watershed management area has one mass loading station, established in 2001, to characterize storm water runoff within the watershed. Since this station was installed, a total of five storm events were monitored at this station. It should be noted that this MLS has less than half the number of data points of the newer San Diego County MLS used for wet-weather monitoring. Sample collection was coordinated by the US Navy for Camp Pendleton (due to security concerns) and results are usually provided to the Copermittees for the purposes of this report. The flow weighted samples are tested for all the same parameters as the Copermittee mass loading stations, with some exceptions that make data comparison between watersheds difficult. The results of the monitoring for the previous storm seasons (not including 2004- 2005) are summarized in Table 4-3. Table 4-3. Analytes measured at the Santa Margarita River mass loading station.2001-0211/29/2001 2/12/2003 2/25/2003 2/3/2004 2/24/2004General / Physical / OrganicElectrical Conductivity umhos/cm 1410 1050 492 1170 643Oil And Grease mg/L 15 USEPA Multi-Sector General Permit <10 <5 <5 <1 <1 0% 0.15pH pH Units 6.5-8.5 Basin Plan 7.9 7.5 7.4 7.8 7.75 0% 0.00BacteriologicalEnterococci MPN/100 mL 130 300 4,106 5,172Fecal Coliform MPN/100 mL 400 Basin Plan>1,600 >1,600 500 1,300100% 3.13Total Coliform MPN/100 mL >1,600 >1,600 2,800 17,000Wet ChemistryAmmonia As N mg/L Basin Plan <0.1 <4 0.1 0.228 0.237Un-ionized Ammonia as Nμg/L 25 (a) Basin Plan <28.9 0.57 NA NA 50% 0.59Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit <5 16 22 14.1 6.72 0% 0.41Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit <30185 44728 18 40% 1.16Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.12 0.26 0.34 0.227 0.279 0% 0.12Nitrate As N mg/L 10 Basin Plan 0.5 1.2 1.5 0.985 1.21 0% 0.11Nitrite As N mg/L 1 Basin Plan <0.1 <0.1 <0.1 <0.5 <0.5 0% 0.13Surfactants (MBAS) mg/L 0.5 Basin Plan 0.05 0.18 <0.04 0.154 0.095 0% 0.20Total Dissolved Solids mg/L 750 Basin Plan by watershed814616 374830446 40% 0.82Total Kjeldahl Nitrogen mg/L <0.5 0.6 0.7 1.92 1.46Total Phosphorus mg/L 2 USEPA Multi-Sector General Permit <0.2 0.3 0.85 0.437 0.309 0% 0.20Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit <5405 3090 22069 60% 7.57Turbidity NTU 20 Basin Plan 2.5193 1160 1470.095 60% 15.03PesticidesChlorpyrifosμg/L 0.02 CA Dept. of Fish & Game <0.01 <3.0* <3.0* 0.0150.04033% 1.00Diazinonμg/L 0.08 CA Dept. of Fish & Game 0.08 <6.0* <6.0* 0.011 0.031 0% 0.51HardnessTotal Hardnessmg CaCO3/L423 341 242 320 225Total MetalsAntimony mg/L 0.006 Basin Plan <0.002 <0.002 <0.002 <0.005 <0.005 0% 0.27Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan <0.002 0.005 0.006 0.002 0.002 0% 0.06Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 0% 0.03Chromium mg/L (b) CTR (Cr VI) 0.004 0.018 0.053 <0.005 <0.005 0% 0.00Copper mg/L (b) 40 CFR 131 0.01 0.0170.0640.008 0.009 20% 0.61Lead mg/L (b) 40 CFR 131 <0.005 0.008 0.039 0.010 0.007Nickel mg/L (b)/0.1 40 CFR 131/ Basin Plan <0.005 0.013 0.024 0.003 0.003 0% 0.01Selenium mg/L 0.02 40 CFR 131 <0.005 0.009 <0.005 <0.005 <0.005 0% 0.19Zinc mg/L (b) 40 CFR 131 0.04 0.05 0.2 0.035 0.027 0% 0.25Dissolved MetalsAntimony mg/L (e) 40 CFR 131 <0.002 <0.002 <0.002 <0.005 <0.005Arsenic mg/L 0.34 (c) 40 CFR 131 <0.002 0.005 <0.002 <0.002 0.002 0% 0.00Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 0% 0.04Chromium mg/L (b) 40 CFR 131 0.003 0.002 0.004 <0.005 <0.005 0% 0.00Copper mg/L (b) 40 CFR 131 0.005 0.009 0.012 <0.005 0.007 0% 0.20Lead mg/L (b) 40 CFR 131 <0.005 0.005 <0.005 <0.002 0.005Nickel mg/L (b) 40 CFR 131 <0.005 0.007 <0.005 <0.002 0.003 0% 0.00Selenium mg/L 0.02 (d) 40 CFR 131 <0.005 0.007 <0.005 <0.005 <0.005 0% 0.02Zinc mg/L (b) 40 CFR 131 <0.010 0.05 0.01 <0.02 0.029 0% 0.07No samples collectedFrequency Above WQOMean Ratio to WQO2003-042004-052002-03ANALYTE UNITS WQO SOURCE Table 4-3. Analytes measured at the Santa Margarita River mass loading station.2001-0211/29/2001 2/12/2003 2/25/2003 2/3/2004 2/24/2004Frequency Above WQOMean Ratio to WQO2003-042004-052002-03ANALYTE UNITS WQO SOURCEToxicityCeriodaphnia 96-hrLC50 (%)100 >100 >100 >100 100 100 0% 0.00Ceriodaphnia 7-day survival NOEC (%) 100 100 100 100 100 100 0% 0.00Ceriodaphnia 7-day reproduction NOEC (%) 100 10050 <25>100 100 40% 1.20Hyalella 96-hr NOEC (%) 100 10050100 100 100 20% 0.40Selenastrum 96-hr NOEC (%) 100 100 100 100 NA 100 0% 0.00SourcesUSEPA Federal Register Document 40 CFR Part 131, May 18, 2000.Blank spaces have been verified and no data is available due to changes in the monitoring program.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.(b) Water Quality Objective for metals are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(e) USEPA has not published an aquatic life criterion value.Shaded text – exceeds water quality objective.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.* Indicates detection limit exceeds water quality objective.USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Table 3 - Parameter benchmark values.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-7 4.2.2 Relationships/Analyses The samples collected at this site were not analyzed for the bacterial indicators total coliform, fecal coliform, and enterococcus in 2001-02; and were analyzed using methods that quantify only up to 1,600 MPN/100 mL in 2002-03. Further, the samples collected at this site had detection limits for some analytes that were different than the detection limits obtained in the rest of the program. The incompatibility of detection limits between this station and other stations in the program makes historical statistical data analysis difficult to accomplish. However, results from the most recent season (2003- 2004) conform to detection limits of other mass loading stations within San Diego County. During the three year monitoring period, fecal coliform concentrations exceeded the WQO in 100% of the storms monitored. Chemical oxygen demand and total dissolved solid concentrations exceeded WQO during two of the five storms (40%) monitored. Exceedances for total suspended solids and turbidity were noted during three of the five storms monitored (60%). There were also single exceedances noted for Chlorpyrifos and total copper (20%). From 2001-2004, toxicity was detected during two storm events (See Section 3.1.6.2 for details on toxicity testing). Results from the chi-square analysis (described in Sections 3.5 and 3.6) showed only a significant relationship (p=0.025) between Ceriodaphnia reproduction and chemical oxygen demand (COD). COD concentrations were only above the water quality objective of 120 mg/L during the same two events that toxicity was detected. In order to illustrate the magnitude of the water quality exceedances, the mean ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern from October 2001 through April 2004. The results are shown in Figure 4-2. The largest average exceedances were for TSS and Turbidity, which exceeded the WQO by approximately 7.5 and 15 times, respectively. Another notable mean exceedance was for fecal coliform, which exceeded the WQO by 3.1 times. Dry weather data can be useful to find the sources of contamination. If similar constituents exceed water quality objectives in both dry and wet weather monitoring, then there is evidence that specific sources are creating pollution that is later being washed down the watershed during storms. The latest data for dry weather monitoring provided useful information, taking into account that it only represents one year of monitoring. Thirteen dry weather stations were sampled in this WMA during the 2004 dry weather monitoring program all of which were located above the MLS (See Section 3.4 for details on dry weather sampling). Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-8 TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 15 Ratio to WQOMean Ratio (Oct 01 to Apr 04)Above WQO Figure 4-2. Santa Margarita River water quality ratios. Table 4-4 shows exceedances for constituents that were measured during the 2004 dry weather monitoring program. Dry weather exceedances occurred for nitrate, turbidity, and oil and grease. The only common COC between the dry and wet weather programs was turbidity, although there was only one dry weather turbidity exceedance. A map for the WMA showing dry weather exceedances is found in Figure 4-3. Pie symbols appear at dry weather stations that have had water quality objective exceedances. The colored slices of the pie show the different constituent groups that contributed to the exceedances. All dry weather sample sites were located in natural or earthen channels. Table 4-4. Santa Margarita River WMA 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* St. Dev. Ratio of Exceedance Turbidity 1 9 0.37 0.50 Nitrate 6 13 1.0 0.92 Oil and Grease 1 11 0.63 1.83 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-9 Figure 4-3. Santa Margarita River WMA dry weather exceedance map. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-10 4.2.3 TIEs The absence of toxicity in the Santa Margarita River storm water samples excluded the need for TIE testing. 4.2.4 Summary and Conclusions Concentrations of nutrients and metals in storm water were relatively low. A more complete assessment will be possible in future years as the limited water quality information in the watershed is expanded. 4.3 Stream Bioassessment Stream bioassessment monitoring in the Santa Margarita River WMA included two urban affected sites in Santa Margarita River proper, as well as two reference sites in the upper tributaries. Two sites on the Santa Margarita River have been established, one along Willow Glen Road, and one on Camp Pendleton near the military base hospital. De Luz Creek and Sandia Creek, north of Fallbrook, are considered good reference creeks because the elevation of these sites is between 400 and 600 feet, which is similar to most of the urban affected monitoring sites in the San Diego County program. One site in De Luz Creek on De Luz/Murietta Road was sampled in October 2004, and a site in Sandia Creek on Sandia Creek Road was sampled in October 2004 and May 2005. Storm water mass loading station information was not collected in this watershed during 2004-2005. 4.3.1 Results and Discussion Willow Glen Road Monitoring Site: SMR-WGR The Santa Margarita River bioassessment test site at Willow Glen Road supported a benthic macroinvertebrate community with an IBI score that was rated Poor for both October 2004 and May 2005 (Table 4-5) (See Section 3.2 for details on the bioassessment sampling approach). Overall taxa richness was seasonally variable, and ranged from 21 to 11 unique taxa, with 8 and 4 different EPT taxa collected. A small but very relevant number of intolerant (tolerance value 0, 1, or 2) organisms comprised one percent of the community in the October survey. The percent tolerant taxa comprised four percent of the community in October, and were absent in May. The physical habitat of the site was optimal, with good stream flow velocity and a complex substrate of stable cobble and boulder, and a largely undisturbed riparian zone of oak, sycamore, and willow. Water quality was good with specific conductance values ranging from 1.224 mS/cm in October 2004 to 0.952 mS/cm in May 2005. pH values were 7.8 and 8.4 in the October and May surveys, respectively. The benthic community was dominated in the October survey by the Hydropsychid caddisflies, Hydropsyche and Cheumatopsyche, and the minnow mayfly Baetis (Table 4-6). The highly intolerant caddisfly, Tinodes, were collected in October, as well as several individuals of the sensitive caddisfly, Oxyethira. In the May survey, the benthic community was dominated by the minnow mayfly, Baetis, the black fly, Simulium, and Chironomid midges. The percent of Hydropsychid caddisflies decreased from Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-11 50% of the community in October to less than 1% in May, likely due to heavy filamentous algae covering most of the exposed rocky substrate. Table 4-5. Selected Biological Metrics and Physical Measures of the Santa Margarita River WMA. Santa Margarita Watershed Management Area Santa Margarita River at Willow Glen Road (SMR-WGR) Santa Margarita River on Camp Pendleton (SMR-CP) De Luz Creek Reference Site on De Luz/Murietta Road (REF-DLC3) Sandia Creek Reference Site on De Luz Road (REF-SC2) Survey Oct-04 May-05 Dec-04 May-05 Oct-04 Oct-04 May-05 20 Poor 17 Poor 15 Poor 24 Poor 50 Good 48 Good 25 Poor Metrics Taxa Richness 21 11 13 17 32 27 24 EPT Taxa (mayflies, stoneflies, and caddisflies) 8 4 5 5 11 8 7 % Intolerant Taxa 1% 0% 0% 0% 26% 23% 4% % Tolerant Taxa 4% 0% 2% 1% 3% 1% 3% Average Tolerance Value 5.0 5.3 5.7 5.0 4.0 4.1 5.2 % Collector Filterers +Collector Gatherers 89% 99% 98% 97% 53% 52% 90% Physical Measures Elevation 500 110 540 440 Physical Habitat Score 176 162 155 153 173 166 161 Riffle Velocity (ft/sec) 1.6 2.8 1.9 2.9 3.1 3.2 2.5 Substrate Composition Silt Sand 23 15% 10% 20% 7% 10% 3% Gravel 23% 7% 23% 17% 12% 12% 23% Cobble 44% 53% 52 33% 58% 65% 54% Boulder 3% 25% 15 30% 20% 13% 20% Bedrock/Solid 7% (roots) 3% Water Quality Temperature ºC 19.1 24.6 12.6 23.1 13.7 14.0 15.5 pH 7.8 8.4 7.7 8.4 7.4 8.2 7.7 Specific Conductance (ms/cm) 1.224 0.952 1.461 1.006 1.655 1.944 1.185 Relative Chlorophyll (μg/L) 1.0 2.0 1.1 0.3 2.3 2.4 0.5 Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-12 Table 4-6. Santa Margarita River WMA Community Summary. Taxon Common Name Percent Composition Tolerance Value Functional Feeding Group Hydropsyche net-spinning caddisfly 32% 4 Collector Filterer Cheumatopsyche net-spinning caddisfly 18% 5 Collector Filterer Baetis minnow mayfly 17% 5 Collector Gatherer Chironomidae non-biting midges 15% 6 Collector Gatherer/Filterer Oct-04 Simulium black fly 3% 6 Collector Filterer Baetis minnow mayfly 53% 5 Collector Gatherer Simulium black fly 22% 6 Collector Filterer Chironomidae non-biting midges 14% 6 Collector Gatherer/Filterer Fallceon quilleri minnow mayfly 7% 4 Collector Gatherer Santa Margarita River at Willow Glen Road (SMR-WGR) May-05 Oligochaeta earthworms 2% 5 Collector Gatherer Simulium black fly 62% 6 Collector Filterer Baetis minnow mayfly 19% 5 Collector Gatherer Chironomidae non-biting midges 8% 6 Collector Gatherer/Filterer Fallceon quilleri minnow mayfly 6% 4 Collector Gatherer Oct-04 Sperchon water mite 1% 5 Predator Fallceon quilleri minnow mayfly 37% 4 Collector Gatherer Simulium black fly 25% 6 Collector Filterer Baetis minnow mayfly 16% 5 Collector Gatherer Chronomidae non-biting midges 11% 6 Collector Gatherer/Filterer Santa Margarita River on Camp Pendleton (SMR-CP) May-05 Hydropsyche net-spinning caddisfly 2% 4 Collector Filterer Hydropsyche net-spinning caddisfly 22% 4 Collector Filterer Micrasema humpless casemaker caddisfly 18% 1 Macrophyte Herbivore Zaitzevia riffle beetle 14% 4 Scraper Argia dancer damselfly 11% 7 Predator Oct-04 Cheumatopsyche net-spinning caddisfly 8% 5 Collector Filterer Baetis minnow mayfly 32% 5 Collector Gatherer Chronomidae non-biting midges 26% 6 Collector Gatherer/Filterer Hydropsyche net-spinning caddisfly 17% 4 Collector Filterer Simulium black fly 10% 6 Collector Filterer Sandia Creek Reference Site at De Luz Road (REF-SC2) May-05 Oligochaeta earthworms 4% 5 Collector Gatherer Micrasema humpless casemaker caddisfly 22% 1 Macrophyte Herbivore Hydropsyche net-spinning caddisfly 21% 4 Collector Filterer Zaitzevia riffle beetle 12% 4 Scraper Baetis minnow mayfly 11% 5 Collector Gatherer De Luz Creek Reference Site on De Luz/Murietta Road (REF-DLC3) Oct-04 Simulium black fly 10% 6 Collector Filterer Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-13 Camp Pendleton Monitoring Site: SMR-CP The monitoring site on Camp Pendleton was rated similar to the Willow Glen Road site, with quality ratings of Poor for both surveys (Table 4-5). There were 13 and 17 different taxa of macroinvertebrates collected in October 2004 and May 2005, respectively, which was a decrease from the previous year when the site had the greatest taxa richness of any of the urban affected (non reference) sites in the San Diego County program (MEC-Weston 2005). The in-stream physical habitat of the sampling transects was different than in previous surveys. The heavy rains of 2004-2005 had scoured much of the sand from a portion of the reach, exposing a large area of cobble and boulder substrate. The overall river course is relatively undisturbed with a good willow dominated riparian zone. Water quality was good with specific conductance ranging from 1.461 to 1.006 ms/cm and pH ranging from 7.7 to 8.4 in October 2004 and May 2005, respectively. The benthic community was dominated in both surveys by the minnow mayflies, Fallceon quilleri and Baetis; the black fly, Simulium; and Chironomid midges (Table 4-6). There were five different EPT taxa collected in both surveys. Two genera of riffle beetles were collected at the site, including Heterelmis in October and Microcylloepus in May, and this was the only non reference site in the program where riffle beetles were collected. De Luz Creek Reference Site: REF-DLC3 The De Luz Creek reference monitoring site had a benthic community with an Index of Biotic Integrity quality rating of Good in the October 2004 survey (Table 4-5). There were 32 different taxa collected, with 11 different EPT taxa. Organisms that are highly intolerant to impairment accounted for 26% of the community, and the average tolerance value was relatively low at 4.0. The riparian zone was dominated by oak and sycamore and the reach had good in-stream characteristics, with diverse microhabitats suitable for macroinvertebrate colonization. Stream flow and current velocity is generally good year-round, even after the extended dry period of 2004. Specific conductance was similar to past years surveys (MEC-Weston 2005) and was relatively high compared to most reference sites, with a value of 1.655 ms/cm (Table 4-5). The benthic community was dominated by the highly intolerant caddisfly, Micrasema (Table 4-6). The net-spinning caddisfly, Hydropsyche, was also abundant. There were numerous taxa collected at this site that were collected only at other reference sites, including Zaitzevia, Malenka, Helichus, Helicopsyche borealis, and Nectosphyche. Sandia Creek Reference Site: REF-SC2 The Sandia Creek reference monitoring site had a benthic community with an Index of Biotic Integrity quality rating of Good in the October 2004 survey, and Poor in the May 2005 survey (Table 4-5). The IBI score for May was one point higher than the highest rated urban influenced site, Santa Margarita River on Camp Pendleton. There were 27 and 24 different taxa collected, with 8 and 7 different EPT taxa in October 2004 and May 2005, respectively. Organisms that are highly intolerant to impairment accounted for 23% in October 2004 and 4% of the community in May 2005. The average tolerance value was 4.1 and 5.2 for the October and May surveys, respectively. The stream habitat was similar to the De Luz Creek reference site, with an oak and sycamore riparian zone and complex in-stream characteristics. Field biologists have noticed increasing removal of native oak trees and the planting of avocado groves upstream of the site. Specific conductance values were Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-14 1.944 and 1.185 ms/cm and pH values were 8.2 and 7.7 for the October 2004 and May 2005 surveys, respectively. The benthic community was variable between the two surveys. For the October survey, the site was dominated by the net-spinning caddisfly, Hydropsyche, and the highly intolerant caddisfly, Micrasema (Table 4-6). The riffle beetle, Zaitzevia, and the damselfly, Argia, were also abundant. For the May survey, the dominant taxa included the minnow mayfly, Baetis, Chironomid midges, and Hydrospyche. Like the other two reference sites, there were a number of intolerant taxa collected that were unique to the site. 4.3.2 Summary and Conclusions The Santa Margarita River WMA was sampled at a total of four monitoring sites, including reference sites in De Luz Creek and Sandia Creek. All of the sites had mostly undisturbed conditions, and the Index of Biotic Integrity quality ratings ranged from Poor to Good. As in past surveys, the monitoring sites in Santa Margarita River were among the highest rated of the urban affected sites in San Diego County, although the IBI scores in May 2005 were lower than usual. Biological metric values and water quality measures indicated that this watershed is one of the least impacted in San Diego County. 4.4 Ambient Bay and Lagoon Monitoring Program 4.4.1 Results and Discussion for Santa Margarita River Estuary There are two coastal embayments in the Santa Margarita River WMA that were monitored in the ABLM Program: Santa Margarita River Estuary and Oceanside Harbor. 4.4.1.1 Phase I Results and Discussion for Santa Margarita River Estuary Sediment samples were collected in Santa Margarita River Estuary for the ABLM Program on June 15, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 4-4. Santa Margarita River Estuary was unique among the 12 embayments sampled in Phase I. The nine sites sampled in Santa Margarita River Estuary had the second highest median grain size (190 μm), the lowest percent fines (5.63%), and the lowest TOC content (0.13%) of any of the twelve embayments assessed (Table 4- 7). Sand was the dominant sediment constituent at all of the nine sites sampled in Santa Margarita River Estuary, accounting for at least 86.3% of the grain size distribution. Figure 4-4. Map of Phase I site locations in Santa Margarita River Estuary. Sites with yellow triangles were selected for Phase II assessment. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-15 Sites 2M-1 and 2R-2 in the middle stratum and Site 1R-1 near the mouth of the Estuary were selected for Phase II assessment (Table 4-7). Site 3R-3 also had a high TOC content but it had a lower percentage of fine sediments than the other sites chosen. Table 4-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Santa Margarita River Estuary. Grain Size Distribution and TOC in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II SME-1L-2 0.00 96.2 1.42 2.35 168 168 3.77 0.07 5 2 7 SME-1M-1 0.00 97.8 1.36 0.88 182 187 2.24 0.05 1 1 2 SME-1R-1 0.06 95.5 2.81 1.62 177 201 4.43 0.10 7 6 13 * Yes SME-2L-1 0.00 97.4 0.57 2.05 185 191 2.62 0.09 2 5 7 SME-2M-1 0.33 86.3 7.52 5.85 136 133 13.37 0.28 8 9 17 * Yes SME-2R-2 0.00 86.3 9.3 4.4 99.5 97.8 13.73 0.25 9 8 17 * Yes SME-3L-1 0.09 96.7 1.27 1.97 274 277 3.24 0.08 4 4 8 SME-3M-1 0.00 97.0 0.85 2.12 193 187 2.97 0.07 3 3 6 SME-3R-3 0.19 95.5 1.73 2.58 295 302 4.31 0.17 6 7 13 * Mean of all Sites 0.08 94.29 2.98 2.65 190.00 193.66 5.63 0.13 St. Dev. 0.12 4.60 3.17 1.53 61.17 63.60 4.55 0.08 4.4.1.2 Phase II Results and Discussion for Santa Margarita River Estuary The three sites selected in the Santa Margarita River Estuary as part of Phase I were sampled in Phase II on July 15, 2004. Sediments from Sites 1R-1, 2M-1 and 2R-2 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 4-8. Table 4-8. Summary of chemistry, toxicity, and benthic community structure in Santa Margarita River Estuary. CHEMISTRY* TOXICITY*BENTHIC COMMUNITY Analyte ERL ERM Result ERM-Q Percent Survival Index 1R-1 2M-1 2R-2 Mean St. Dev.Total METALS (mg/kg) Abundance 198 116 109 141 49.5 423 Antimony NA NA <1.74 NA Richness 15 8 10 11 3.61 18 Arsenic 8.2 70 1.67 0.024 Diversity 1.67 1.67 1.84 1.73 0.10 NA Cadmium 1.2 9.6 <0.174 NA Evenness 0.62 0.80 0.80 0.74 0.10 NA Chromium 81 370 13.2 0.036 Dominance 3 4 4 3.67 0.58 NA Copper 34 270 6.45 0.024 Lead 46.7 218 5.13 0.024 Nickel 20.9 51.6 4.92 0.095 Selenium NA NA <1.74 NA Zinc 150 410 37.2 0.091 Mean ERM-Q 0.049 97% Not Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-16 Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these only six metals were detected above the detection limit in sediments from the Santa Margarita River Estuary: arsenic, chromium, copper, lead, nickel, and zinc (Table 4-8). All concentrations were very low and none exceeded the ERL or the ERM. Thus, the mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was also very low (0.049). The same six metals were detected above detection limits during the 2003 ABLM program which also had a very low mean ERM quotient (0.05). There were no PAHs, PCBs, or pesticides found above the detection limit in Santa Margarita River Estuary. The mean ERM-Q for Santa Margarita River Estuary was the lowest of any of the 12 embayments assessed in the ABLM Program and well below the threshold of 0.10. This estuary also had the lowest ERM-Q value during the 2003 ABLM program. Sediments with mean ERM-Q values below this threshold have a low probability of producing adverse biological effects (Long et al. 1998). Toxicity. The percent survival of E. estuarius exposed to Santa Margarita River sediments in a 10-day acute toxicity test was 97% (Table 4-8). Percent survival was not significantly different from that of the Control (99%), suggesting that Santa Margarita River Estuary sediments were not toxic to the test organisms. This is similar to the results from the 2003 ABLM program where no toxicity was observed. Benthic Community Structure. A total of 423 organisms were collected from Santa Margarita River Estuary, representing 18 taxa (Table 4-8). Taxa abundance and richness were higher at Site 1R-1 at the mouth of the Estuary than the other two sites, but diversity and evenness were lower. Dominance was close to the same at all sites (3,4,4). Based on these indices, the benthic community structure had a rank of 5, where 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. During the 2003 ABLM program a total of 529 organisms were collected, representing 16 taxa. One species dominated the infaunal community in Santa Margarita River Estuary: Cerithidea californica, the California Horn Snail, which accounted for 28.6% of all the animals collected (Table 4-9). Probably the most common snail in southern California lagoon mudflats, Cerithidea is highly tolerant to temperature and salinity fluxes. The polychaete worm, Pseudopolydora paucibranchiata, was the second most common species found in Santa Margarita River Estuary, followed by the gammarid amphipod, Grandidierella japonica. During the 2003 ABLM program, Grandidierella japonica dominated the infaunal community and accounted for 63.7% of all animals collected. Table 4-9. Dominant infaunal species found in the Santa Margarita River Estuary during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Cerithidea californica Mollusc 121 28.6 Pseudopolydora paucibranchiata Polychaete 100 23.6 SME Grandidierella japonica Crustacean 79 18.7 Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-17 Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Santa Margarita River Estuary were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 4-5. For Santa Margarita River Estuary, the relative ranks were one for chemistry, two for toxicity and five for benthic community structure. 4.4.1.3 Summary and Conclusions for Santa Margarita River Estuary Sediments in Santa Margarita River Estuary were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grain size): site 1R-1 in the outer stratum of the Estuary and sites 2M-1 and 2R-2 in the middle stratum. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that only six metals were found in the Estuary sediments, all at very low concentrations. Sediment toxicity was also low and not significantly different from that of a Control sample. Benthic community indices suggested that biotic community in the Estuary sediments were similar to other embayments in the County and was dominated by a gastropod and polychaete worms. Compared to the other embayments in San Diego County, the relative ranks for Santa Margarita River Estuary were one for chemistry, two for toxicity and five for benthos. Compared to the other embayments in the 2004 ABLM program, Santa Margarita River Estuary had an overall rank of one. During the 2003 ABLM program the Estuary had an overall rank of two. The decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 0 1 2 3 4 5 6 Chemistry Toxicity Benthos RankingFigure 4-5. Relative rankings for sediment in Santa Margarita River Estuary. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-18 4.4.2 Results and Discussion for Oceanside Harbor 4.4.2.1 Phase I Results and Discussion for Oceanside Harbor Sediment samples were collected in Oceanside Harbor for the ABLM Program on June 9, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 4-6. Unlike all the other sites assessed in Phase I, although storm drains discharge to Oceanside Harbor, it has no direct freshwater input from a major watershed. Therefore, the inner stratum was designated as the area farthest from the harbor breakwaters, which included all of the boat slips in North and South Harbor. The middle and outer strata roughly divide the main basin. The area north of the main basin is located on military property and was inaccessible at the time of the survey. All three of the inner stratum sites had much smaller median grain sizes and a larger proportion of fine sediments than any of the sites in the middle and outer strata. (Table 4-10) The inner strata sites also had higher TOC levels than the other sites. This pattern was particularly clear at Sites 3M-1 and 3R-1 (which are located in the south boat basin). Tidal flushing is most likely limited in this area, allowing for the deposition of fine-grained, high TOC sediments. All three sites in the inner strata of Oceanside Harbor (3L-1, 3M-1, 3R-1) were selected for Phase II assessment. Table 4-10. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Oceanside Harbor. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II OH-1L-1 0.29 98.0 0.94 0.79 149 151 1.72 0.06 1 1 2 OH-1M-1 0.00 87.3 9.9 2.77 92.9 89.7 12.69 0.23 5 4 9 OH-1R-1 0.00 79.3 15.20 5.47 115 70 20.66 0.38 6 6 12 OH-2L-1 0.29 94.5 2.85 2.40 113 116 5.25 0.24 2 5 7 OH-2M-1 0.50 92.7 5.68 1.12 99 102 6.80 0.12 3 3 6 OH-2R-2 0.27 89.0 9.30 1.42 92 121 10.71 0.11 4 2 6 OH-3L-1 0.04 37.0 39.6 23.3 26.0 14.9 62.91 1.07 7 8 15 * Yes OH-3M-1 0.07 11.0 62.3 26.7 12.7 7.48 88.96 1.29 9 9 18 * Yes OH-3R-1 0.01 36.5 41.5 22.0 28.4 14.29 63.45 0.77 8 7 15 * Yes Mean of all Sites 0.16 69.48 20.81 9.54 80.98 76.20 30.35 0.47 St. Dev. 0.18 32.28 21.60 10.99 47.23 52.90 32.38 0.46 Figure 4-6. Map of Phase I site locations in Oceanside Harbor. Sites with yellow triangles were selected for Phase II assessment. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-19 4.4.2.2 Phase II Results and Discussion for Oceanside Harbor The three sites selected in the Oceanside Harbor as part of Phase I were sampled in Phase II on July 14, 2004. Sediments from Sites 3L-1, 3M-1 and 3R-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 4-11. Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, seven metals were detected above the detection limit in sediments from Oceanside Harbor in 2004: arsenic, chromium, copper, lead, nickel, selenium and zinc (Table 4-11). All concentrations were low and none exceeded the ERM during 2004. However, concentrations of copper and zinc exceeded their respective ERLs. With the exception of selenium, the same metals were detected above the detection limit during the 2003 ABLM program. All metal concentrations were low and did not exceed the ERM during 2003, however copper and zinc did exceed their respective ERLs. Table 4-11. Summary of chemistry, toxicity, and benthic community structure in Oceanside Harbor. CHEMISTRY* TOXICITY* BENTHIC COMMUNITY Analyte ERL ERM Result ERM- Q Percent Survival Index 3L- 1 3M-1 3R-1 Mean St. Dev. Total METALS (mg/kg) Abundance 495 298 223 338.7 140.5 1016 Antimony NA NA <1.74 NA Richness 39 46 37 40.67 4.73 75 Arsenic 8.2 70 8.15 0.116 Diversity 2.45 3.10 2.86 2.80 0.33 NA Cadmium 1.2 9.6 <.174 NA Evenness 0.67 0.81 0.79 0.76 0.08 NA Chromium 81 370 42.2 0.114 Dominance 7 12 10 9.67 2.52 NA Copper 34 270 116 0.430 Lead 46.7 218 19.6 0.090 Nickel 20.9 51.6 15 0.291 Selenium NA NA 1.63 NA Zinc 150 410 177 0.432 Mean ERM-Q 0.245 86% Not Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value During 2004, Oceanside Harbor was one of only three sites assessed where selenium was found in the sediments (Mission Bay and Los Peñasquitos were the other two sites). There were no PAHs, PCBs, or pesticides found above the detection limit in Oceanside Harbor. During the 2003 ABLM program Oceanside Harbor was one of only two sites assessed where PAHs were found in the sediments. The concentrations of all four PAHs found last year were low and well below their respective ERLs. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was low for all sites assessed in 2004 when compared to published values (Long et al. 1998). The mean ERM-Q for Oceanside Harbor was 0.245, which exceeded the threshold of 0.10. Sediments with mean ERM-Q values above this threshold have a greater probability of producing adverse biological effects than embayments with mean ERM-Qs below the threshold (Long et al. 1998). Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-20 Toxicity. The percent survival of E. estuarius exposed to Oceanside Harbor sediments in a 10-day acute toxicity test was 86 % (Table 4-11). Percent survival was not significantly different from that of the Control (99%), suggesting that Oceanside Harbor sediments were not toxic to the test organisms. During the 2003 ABLM program toxicity was detected, but the source of the toxicity was unknown. Benthic Community Structure. A total of 1016 organisms were collected from Oceanside Harbor, representing 75 taxa (Table 4-11). Taxa abundance at Oceanside Harbor was similar to other embayments assessed, but taxa richness was among the highest, second to Mission Bay and slightly ahead of Sweetwater River Estuary. This is similar to the 2003 ABLM program where Oceanside Harbor was also among the top three sites for taxa richness with 522 organisms collected representing 55 taxa. Among the three sites assessed in Oceanside Harbor during 2004, Site 3L-1 had the greatest abundance, but Site 3M-1 had the greatest richness, diversity, evenness, and dominance (Table 4-11). The benthic community of Oceanside Harbor ranked high among the other ABLM sites in species diversity and richness (1 and 2 respectively), but low in abundance (9). Based on these indices, the benthic community structure in Oceanside Harbor received a ranking of two, which was the second highest among the embayments assessed in the 2004 ABLM Program (see Section 13.5 for a complete discussion). A rank of 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. Similar to the 2003 ABLM program, polychaete worms dominated the infaunal community in Oceanside Harbor during the 2004 ABLM program. Scoletoma sp and Pseudopolydora paucibranchiata each accounted for 18.9% of all the animals collected (Table 4-12). The polychaete worm, Euchone limnicola, was the next most abundant taxa, accounting for 5.9% of the community. During the 2003 ABLM program Pseudopolydora paucibranchiata dominated the infaunal community and accounted for 51.3% of all the animals collected. Table 4-12. Dominant infaunal species found in Oceanside Harbor during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Scoletoma sp Polychaete 193 18.9 Pseudopolydora paucibranchiata Polychaete 192 18.9 OH Euchone limnicola Polychaete 60 5.9 Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Oceanside Harbor were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 4-7. For Oceanside Harbor, the relative ranks were 10 for chemistry, 6 for toxicity, and 2 for benthic community structure. 0 2 4 6 8 10 12 Chemistry Toxicity Benthos RankingFigure 4-7. Relative rankings for sediment in Oceanside Harbor. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-21 4.4.2.3 Summary and Conclusions for Oceanside Harbor Sediments in Oceanside Harbor were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grain size). All three sites were located in the inner Harbor. In Phase II of the assessment these sites were analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven metals were found in the Harbor sediments. All of the COC were found at low concentrations, except copper and zinc, which were slightly elevated. Percent survival of test organisms exposed to Oceanside Harbor sediments was 86%, which was not significantly different from that of the Control. The benthic community in Oceanside Harbor ranked second highest among the embayments assessed in the ABLM Program based on benthic community indices. The community was dominated by polychaete worms, especially Scoletoma sp. and the tube building polychaete, Pseudopolydora paucibranchiata. For Oceanside Harbor, the relative ranks were 10 for chemistry, 6 for toxicity, and 2 for benthos. Compared to the other embayments in the 2004 ABLM program, Oceanside Harbor had an overall rank of six. During the 2003 ABLM program the Harbor had an overall rank of seven. The decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 4.5 WMA Assessment The Santa Margarita watershed was assessed in order to identify water quality issues within the watershed and to develop short and long-term planning actions to address these issues. The assessment included chemistry and toxicity data collected during storm events from a MLS on Santa Margarita River, chemistry data collected during dry weather, and stream bioassessment IBI ratings. Constituent of concern criteria were developed to prioritize COC for each watershed. The watershed management area assessment methods, discussed in Section 3.4, were applied to these data to determine the constituents of concern and to develop a frequency of occurrence ranking (high, medium, or low). Constituent exceedances in wet and dry weather are summarized in Table 4-13. The cumulative column shows the frequency of occurrence from the 2001-2002 storm season through the 2003-2004 storm season. Wet weather sampling was not conducted during the 2004-2005 storm season, however dry weather sampling and stream bioassessment were conducted during 2004-2005. The IBI rating was assigned based on the average of the IBI scores of non-reference bioassessment sites in the watershed. In the Santa Margarita River, two constituents were identified as having a high frequency of occurrence and received three diamonds. These constituents include: • Fecal Coliform • Turbidity Fecal coliform received three diamonds based on Criterion No. 1 and turbidity received three diamonds based on Criterion No. 3. One constituent had a medium frequency of occurrence and was assigned two diamonds based on Criterion No. 5. This constituent was: • Total suspended solids Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-22 Table 4-13. Constituent exceedances in the Santa Margarita River WMA. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/1 % #/2 % #/2 % # % #/5 % # % Frequency of Occurrence Criterion No. Conventional Parameters Oil and Grease 0 0 0 0 0 0 NA NA 0 0 1 9 - - COD 0 0 2 100 0 0 NA NA 2 40 NA NA - - Total Dissolved Solids 1 100 0 0 1 50 NA NA 2 40 NA NA ♦ 9 Total Suspended Solids 0 0 2 100 1 50 NA NA 3 60 NA NA ♦♦ 5 Turbidity 0 0 2 100 1 50 NA NA 3 60 1 11 ♦♦♦ 3 Nutrients Nitrate as N 0 0 0 0 0 0 NA NA 0 0 6 46 ♦ 8 Bacteriological Fecal Coliform NA NA 2 100 2 100 NA NA 4 100 0 0 ♦♦♦ 1 Pesticides Chlorpyrifos 0 0 0 0 1 50 NA NA 1 20 NA NA - - Total Metals Chromium 0 0 2 100 0 0 NA NA 2 40 NA NA - - Copper 0 0 1 50 0 0 NA NA 1 20 NA NA - - Zinc 0 0 1 50 0 0 NA NA 1 20 NA NA - - Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 7-day reproduction 0 0 2 100 0 0 NA NA 2 40 NA NA No Hyalella 96-hour 0 0 1 50 0 0 NA NA 1 20 NA NA No Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? Santa Margarita River at Willow Glen Rd. NA Poor Fair Poor Poor NA Santa Margarita River, Camp Pendleton (DS) NA Poor Fair Poor Poor NA No * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS Two constituents were identified as having a low frequency of occurrence and assigned one diamond. These constituents include: • Total dissolved solids • Nitrate During the 2002-2003 storm season, there were exceedances of chemical oxygen demand, total chromium, copper, and zinc concentrations and there was evidence of toxicity, however there were no exceedances of these constituents or toxicity present during the 2001-2002 and 2003-2004 seasons. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-23 Persistent toxicity is evident when more than 50% of the toxicity tests conducted on any species have a NOEC of less than 100%. Even though there was evidence of toxicity during the 2002-2003 storm season, there was no evidence of persistent toxicity in the Santa Margarita River watershed throughout the duration of the monitoring period. IBI scores from bioassessment monitoring from two sites in the Santa Margarita River have varied between poor and fair conditions throughout the monitoring period. These results indicate that there is no evidence of benthic alteration. Even though the Santa Margarita River benthic communities were rated as poor, the habitats were generally ranked as the best in San Diego County. Figure 4-8 illustrates the number of wet weather exceedances for each monitoring season for six categories of constituents, including conventional parameters, nutrients, bacteria, pesticides, metals and toxicity. The stacked bar charts were developed using the number of exceedances from values in Table 4-13 for each constituent category. This displays a conceptual picture of water quality concerns in the watershed over time. The overall number of exceedances of water quality objectives for the Santa Margarita River watershed was the lowest during 2001-2002 and highest during 2002-2003. Conventional parameters, such as TSS and turbidity, constituted the most number of exceedances for all three monitoring seasons. During 2003-2004, bacteriological parameters constituted the second highest number of exceedances while metal constituents made up the second highest number of exceedances during the 2002-2003 season. Santa Margarita River Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 4-8. Stacked bar chart of the number of wet weather exceedances of constituent groups in Santa Margarita River. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-24 Triad Decision Matrix The data from wet and dry weather, toxicity and bioassessment monitoring efforts were evaluated for this watershed using the triad decision matrix. The triad decision matrix incorporates the chemistry data from wet and dry weather events with the toxicity and bioassessment results to provide indications of pollutant loading, potential impacts to organisms and the ecological health of the watershed. The triad assessment presents possible conclusions about the watershed and provides possible actions or decisions for future monitoring and assessment. Table 4-14 summarizes these results. Table 4-14. Decision matrix results for Santa Margarita River WMA. Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions Persistent exceedances of water quality objectives (high frequency COC identified) No persistent evidence of toxicity No Indications of alteration Limited dataset makes conclusions difficult. Test organisms not sensitive to problem pollutants. Contaminants are not bioavailable. 1) Continue monitoring to gather long-term trend information. 2) Continue monitoring for toxic and benthic impacts. Consider whether different or additional test organisms should be evaluated. 3) Initiate upstream source identification as a low priority. 4) TIE would not provide useful information with no evidence of toxicity. Based on the triad matrix, there was evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and no indications of benthic alteration. The recommended actions for the Santa Margarita River watershed are to continue monitoring for all elements of the program to gather additional data for assessment and long-term trend analysis, continue monitoring for toxic and benthic impacts and to initiate upstream source identification to determine sources of constituents of concern. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Santa Margarita River WMA The water quality priority ratings presented in Table 4-15 are based on the methodology presented in the BLTEA report (WESTON, MOE, & LWA 2005) and are presented in the Methods Section 3.4. Constituent groups and stressor groups are given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicate that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on current results presented in this 2004-2005 annual report and data from the following programs: • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Co-permittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303d Listing Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-25 Table 4-15. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Santa Margarita River WMA. Priority Ratings* Constituent Groups Stressor Groups Watersheds/Sub- watersheds Percentage of Total Area Heavy Metals Organics Oil and Grease Sediments Pesticides Nutrients Gross Pollutants Bacteria/ Pathogens Benthic Alterations Toxicity Santa Margarita WMA 100% C D D A C B B B B C Ysidora HA (902.10) 11% D D D A C A C A B C DeLuz HA (902.20) 29% D D D A C A C C B C Pechanga HA (902.50) 12% C D D B D A B B B C Aguanga HA (902.80) 28% C D D B D D B B B C Oakgrove HA (902.90) 20% C D D B D D B B B C Notes: * = Rating Calculated Based on Area Weighted Averages of Score Value from the sub-watershed areas. ** = Priority Level (Highest-A to Lowest-D) The purpose of the BLTEA ratings is to identify water quality priorities within a watershed based on weighted averages of the sub-watershed ratings. Because it is a weighted average, larger sub-watersheds will have a greater influence in the overall watershed rating. Sediment was rated as the highest priority constituent (A) overall for the Santa Margarita River WMA, followed by nutrients, gross pollutants, bacteria, and benthic alterations which were all given a B rating. All other constituent groups or stressors were given a C or D rating. The Ysidora sub-watershed which accounts for 11% of the total Santa Margarita River WMA had high priority (A) ratings for sediments, nutrients, and bacteria. The DeLuz sub-watershed which accounts for 29% of the total Santa Margarita River WMA had high priority (A) ratings for sediments and nutrients. The Pechanga sub-watershed which accounts for 12% of the total Santa Margarita River WMA, had a high priority (A) rating only for nutrients. The Aguanga sub-watershed, which accounts for 28%, and the Oakgrove sub-watershed, which accounts for 20%, did not have any high priority (A) ratings for any constituent group. All of the sub-watersheds had B ratings for benthic alteration. A regional evaluation and description of the BLTEA is presented in the Regional Assessment Section 13. The complete tables used to calculate the ratings are presented in Appendix G. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-26 4.6 Conclusions and Recommendations The Santa Margarita River watershed is the second largest in the San Diego hydrologic region. The primary land use within the contributing runoff area is undeveloped (64%). For the Santa Margarita River WMA, turbidity and fecal coliform were identified as high frequency of occurrence COC, TSS was identified as a medium frequency of occurrence COC, and TDS and nitrate were identified as low frequency of occurrence COC. There was no evidence of persistent toxicity found in Santa Margarita River. The stream habitat quality varied between poor and fair which indicated that there was no evidence of benthic alteration. Based on the Ambient Bay and Lagoon Monitoring Program, the relative ranks for Santa Margarita River Estuary were one for chemistry, two for toxicity and five for benthos. Compared to the other embayments in the 2004 ABLM program, Santa Margarita River Estuary had an overall rank of one. The relative ranks for Oceanside Harbor were 10 for chemistry, 6 for toxicity, and 2 for benthos. The benthic community ranked second highest among other embayments within San Diego County. Compared to the other embayments in the 2004 ABLM program, Oceanside Harbor had an overall rank of six. The relative quality for both Santa Margarita River Estuary and Oceanside Harbor increased from the ABLM 2003 monitoring year. The WMA assessment findings agreed with the BLTEA rating priorities for the Santa Margarita River WMA, which found sediments to be a high priority (A rating) constituent. The BLTEA ratings also gave a B rating to nutrients, bacteria, gross pollutants and benthic alteration. The information provided from the triad matrix results used in conjunction with the BLTEA ratings can assist the jurisdictions in making informed decisions in developing their WURMP programs. The two reports also allow for an evaluation of where data gaps exist and where efforts should be targeted. Utilizing the BLTEA rating methods for future data evaluations would also allow for long- term BMP effectiveness assessment. Incorporation of additional useable data from other third party sources such as publicly owned treatment works (POTWs) or non-profit organizations would also help to increase the confidence of the BLTEA ratings and overall WMA assessments. The recommendations for this watershed are to continue monitoring to determine long-term trends, continue monitoring for toxic and benthic impacts and to identify upstream sources of constituents of concern. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-1 4.0 SANTA MARGARITA RIVER WMA 4.1 Monitoring Site Descriptions The Santa Margarita River watershed management area includes the Santa Margarita watershed (HU 902.00). The Santa Margarita watershed is the second largest in the San Diego hydrologic region. It covers over 475,459 acres, with the majority of the watershed lying in Riverside County and just 26.6% in San Diego County (Figure 4-1). The watershed is made up of the following nine hydrologic areas: Ysidora, De Luz, Murrieta, Auld, Pechanga, Wilson, Cave Rocks, Aguanga, and Oak Grove. Major water bodies include the Santa Margarita River, Temecula Creek, Murrieta Creek, Santa Margarita Lagoon, Vail Lake, Lake O'Neill, Skinner Reservoir, and Diamond Valley Lake Reservoir. The Santa Margarita River is the least disturbed river system south of Santa Barbara County, and provides habitat for some of the largest remaining populations of several bird species. There are nine dams located in the watershed with 92% of the river miles categorized as free flowing. Lake O'Neill is not located in the river channel but does receive much of its water from seasonal river diversions (Coastal Conservancy 2001). Jurisdiction in the watershed is dominated by Riverside County (73.4%), with the remaining areas lying in unincorporated San Diego County and only 98 acres falling under the City of Oceanside. The southwestern portion of the watershed is dominated by Camp Pendleton Naval Reservation and Marine Corps Base. Military ownership makes up 8% of the watershed. This has kept the lower river and estuary from being developed and therefore, this region supports a variety of valuable habitats and other beneficial uses (Table 4-1). Table 4-1. Beneficial uses within the Santa Margarita watershed. Beneficial Uses Inland Surface Waters Coastal Waters Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z z z Agricultural Supply z z z Industrial Service Supply z z z Industrial Process Supply z z z Ground Water Recharge O z Navigation Contact Water Recreation z z z1 Non-Contact Water Recreation z z z Commercial and Sport Fishing Warm Freshwater Habitat z z Cold Freshwater Habitat z z Biological Habitats of Special Significance Estuarine Habitat z Wildlife Habitat z z z Rare, Threatened, or Endangered Species z z z Marine Habitat z Migration of Aquatic Organisms z Shellfish Harvesting Aquaculture Spawning, Reproduction and/or Early Development z = Existing; O = Potential 1 Shore and boat fishing only. Other REC1 uses prohibited. Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-2 Figure 4-1. Santa Margarita River Watershed Management Area. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-3 The upper portion of the watershed in Riverside County is under continued development. Major impacts to the watershed include surface and groundwater quality degradation, habitat loss, invasive species, and channel bed erosion. Constituents of concern are nitrate (surface and groundwater), sediment, coliform bacteria, and TDS in groundwater. Sources of these contaminants include agriculture, livestock and domestic animals, septic systems, use of recycled water, and urban runoff (San Diego County 2001). Currently there are five water bodies from this watershed listed on the SWRCB 2002 303(d) list (Table 4-2). The principal aquifer in the watershed is the Santa Margarita Basin. Annual precipitation for the portion of the watershed within the San Diego area ranges from 10.5 inches in the coastal areas to more than 16.5 inches in the eastern portion of the watershed (Figure 4-1). Table 4-2. Water bodies on the SWRCB 303(d) list in the Santa Margarita watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor Santa Margarita Lagoon Lower Ysidora 902.11 Eutrophic Rainbow Creek Gavilan 902.22 Nitrogen, Phosphorus Upper Santa Margarita River Gavilan 902.22 Phosphorus Sandia Creek Gavilan 902.22 TDS Murrieta Creek Wolf 902.52 Phosphorus Source: SWRCB 2003 The Santa Margarita River (SMR) mass loading station is within this watershed management area and is located on Camp Pendleton, north of Vandegrift Boulevard, under the Basilone Road Bridge. The Santa Margarita River is a natural channel at the sampling point. The contributing runoff area within San Diego County covers over 121,400 acres, which is approximately 26% of the total watershed area. The primary land use within the contributing runoff area is undeveloped (64%). Stream Bioassessment sampling in the Santa Margarita River WMA included several reference sites in Sandia and De Luz Creeks, as well as urban affected monitoring sites in the Santa Margarita River proper. All of the monitoring reaches in the upper watershed areas north of the city of Fallbrook have good year-round flow, relatively high gradients, and high quality in- stream habitats with stable cobble and boulder substrates. In the lower reaches of the River in Camp Pendleton, the gradient levels off and the primary substrate component is coarse unconsolidated sand with banks that support dense riparian vegetation. The Santa Margarita River flows into the Santa Margarita River Estuary before it enters the ocean. The Estuary is located in the southwestern corner of Camp Pendleton Marine Corps Base, approximately one mile north of the City of Oceanside. The Estuary encompasses approximately 192 acres of wetland habitat, the majority of which is designated as salt pan and salt marsh habitat (Coastal Conservancy 2000). The Santa Margarita River is the primary source of fresh water to the Estuary, but runoff and groundwater seepage also contribute fresh water to the area. The Estuary is open to the ocean intermittently through a series of narrow channels, but tidal influence is constrained by rock jetties at Interstate 5 and railroad crossings. Secondarily treated sewage was discharged to the Estuary from the 1940s through the 1970s and the salt flats have been used for military training exercises in the past. Currently, the Estuary is listed as impaired for eutrophic conditions on the SWRCB’s 2002 303(d) list and Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-4 has been since 1998 (Table 4-2). Other potential environmental pressures on the Estuary include invasive exotic vegetation, development in the upper watershed, and increased sedimentation. The Estuary consists of a central portion that is approximately 4,000 feet long by 1,500 feet wide at its widest point and a smaller arm that extends to the south. Three sites in the Santa Margarita River Estuary were sampled during the Ambient Bay and Lagoon Monitoring Program. Two were located in the upper portion of the Estuary between Interstate 5 and the ocean and one was located in the southern portion of the Estuary closer to the mouth (Figure 4-1). Oceanside Harbor is also located in the Santa Margarita River WMA. Oceanside Harbor was unique among the sites monitored in the ABLM Program because it is the only site that is not hydrologically connected to a watershed and thus has no major fresh water inputs. The Harbor has three main regions: an inner harbor, which contains all of the boat slips and boating facilities, a middle harbor, adjacent to the mouth of the inner harbor, and an outer harbor that parallels the rip rap breakwater. These natural features were used to delineate the three strata for the ABLM sampling (Figure 4-1). Connected to Oceanside Harbor to the north is another large area known as Del Mar Boat Basin, located on Camp Pendleton Marine Base. Access to this area was restricted and no samples were taken in Del Mar Boat Basin. The characteristics of the inner harbor are distinctly different from those in the middle and outer harbor. The inner harbor is relatively shallow with limited flushing due to tidal restrictions at its mouth. The middle and outer harbor areas are deeper, particularly near the harbor entrance and tidal exchange is much greater than that in the inner harbor. The three sites selected for assessment in the ABLM program were located in the inner harbor due to the fine grain size and high TOC levels in this area. 4.2 Storm Water Monitoring Summary 4.2.1 2004/2005 Results The Navy Public Works Center did not perform monitoring on the Santa Margarita River during the 2004-2005 season due to sampling equipment being lost in flooding during the first rain event. The Navy indicated that they would not sample during the remainder of the 2004-2005 wet-season. This watershed management area has one mass loading station, established in 2001, to characterize storm water runoff within the watershed. Since this station was installed, a total of five storm events were monitored at this station. It should be noted that this MLS has less than half the number of data points of the newer San Diego County MLS used for wet-weather monitoring. Sample collection was coordinated by the US Navy for Camp Pendleton (due to security concerns) and results are usually provided to the Copermittees for the purposes of this report. The flow weighted samples are tested for all the same parameters as the Copermittee mass loading stations, with some exceptions that make data comparison between watersheds difficult. The results of the monitoring for the previous storm seasons (not including 2004- 2005) are summarized in Table 4-3. Table 4-3. Analytes measured at the Santa Margarita River mass loading station.2001-0211/29/2001 2/12/2003 2/25/2003 2/3/2004 2/24/2004General / Physical / OrganicElectrical Conductivity umhos/cm 1410 1050 492 1170 643Oil And Grease mg/L 15 USEPA Multi-Sector General Permit <10 <5 <5 <1 <1 0% 0.15pH pH Units 6.5-8.5 Basin Plan 7.9 7.5 7.4 7.8 7.75 0% 0.00BacteriologicalEnterococci MPN/100 mL 130 300 4,106 5,172Fecal Coliform MPN/100 mL 400 Basin Plan>1,600 >1,600 500 1,300100% 3.13Total Coliform MPN/100 mL >1,600 >1,600 2,800 17,000Wet ChemistryAmmonia As N mg/L Basin Plan <0.1 <4 0.1 0.228 0.237Un-ionized Ammonia as Nμg/L 25 (a) Basin Plan <28.9 0.57 NA NA 50% 0.59Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit <5 16 22 14.1 6.72 0% 0.41Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit <30185 44728 18 40% 1.16Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.12 0.26 0.34 0.227 0.279 0% 0.12Nitrate As N mg/L 10 Basin Plan 0.5 1.2 1.5 0.985 1.21 0% 0.11Nitrite As N mg/L 1 Basin Plan <0.1 <0.1 <0.1 <0.5 <0.5 0% 0.13Surfactants (MBAS) mg/L 0.5 Basin Plan 0.05 0.18 <0.04 0.154 0.095 0% 0.20Total Dissolved Solids mg/L 750 Basin Plan by watershed814616 374830446 40% 0.82Total Kjeldahl Nitrogen mg/L <0.5 0.6 0.7 1.92 1.46Total Phosphorus mg/L 2 USEPA Multi-Sector General Permit <0.2 0.3 0.85 0.437 0.309 0% 0.20Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit <5405 3090 22069 60% 7.57Turbidity NTU 20 Basin Plan 2.5193 1160 1470.095 60% 15.03PesticidesChlorpyrifosμg/L 0.02 CA Dept. of Fish & Game <0.01 <3.0* <3.0* 0.0150.04033% 1.00Diazinonμg/L 0.08 CA Dept. of Fish & Game 0.08 <6.0* <6.0* 0.011 0.031 0% 0.51HardnessTotal Hardnessmg CaCO3/L423 341 242 320 225Total MetalsAntimony mg/L 0.006 Basin Plan <0.002 <0.002 <0.002 <0.005 <0.005 0% 0.27Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan <0.002 0.005 0.006 0.002 0.002 0% 0.06Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 0% 0.03Chromium mg/L (b) CTR (Cr VI) 0.004 0.018 0.053 <0.005 <0.005 0% 0.00Copper mg/L (b) 40 CFR 131 0.01 0.0170.0640.008 0.009 20% 0.61Lead mg/L (b) 40 CFR 131 <0.005 0.008 0.039 0.010 0.007Nickel mg/L (b)/0.1 40 CFR 131/ Basin Plan <0.005 0.013 0.024 0.003 0.003 0% 0.01Selenium mg/L 0.02 40 CFR 131 <0.005 0.009 <0.005 <0.005 <0.005 0% 0.19Zinc mg/L (b) 40 CFR 131 0.04 0.05 0.2 0.035 0.027 0% 0.25Dissolved MetalsAntimony mg/L (e) 40 CFR 131 <0.002 <0.002 <0.002 <0.005 <0.005Arsenic mg/L 0.34 (c) 40 CFR 131 <0.002 0.005 <0.002 <0.002 0.002 0% 0.00Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 0% 0.04Chromium mg/L (b) 40 CFR 131 0.003 0.002 0.004 <0.005 <0.005 0% 0.00Copper mg/L (b) 40 CFR 131 0.005 0.009 0.012 <0.005 0.007 0% 0.20Lead mg/L (b) 40 CFR 131 <0.005 0.005 <0.005 <0.002 0.005Nickel mg/L (b) 40 CFR 131 <0.005 0.007 <0.005 <0.002 0.003 0% 0.00Selenium mg/L 0.02 (d) 40 CFR 131 <0.005 0.007 <0.005 <0.005 <0.005 0% 0.02Zinc mg/L (b) 40 CFR 131 <0.010 0.05 0.01 <0.02 0.029 0% 0.07No samples collectedFrequency Above WQOMean Ratio to WQO2003-042004-052002-03ANALYTE UNITS WQO SOURCE Table 4-3. Analytes measured at the Santa Margarita River mass loading station.2001-0211/29/2001 2/12/2003 2/25/2003 2/3/2004 2/24/2004Frequency Above WQOMean Ratio to WQO2003-042004-052002-03ANALYTE UNITS WQO SOURCEToxicityCeriodaphnia 96-hrLC50 (%)100 >100 >100 >100 100 100 0% 0.00Ceriodaphnia 7-day survival NOEC (%) 100 100 100 100 100 100 0% 0.00Ceriodaphnia 7-day reproduction NOEC (%) 100 10050 <25>100 100 40% 1.20Hyalella 96-hr NOEC (%) 100 10050100 100 100 20% 0.40Selenastrum 96-hr NOEC (%) 100 100 100 100 NA 100 0% 0.00SourcesUSEPA Federal Register Document 40 CFR Part 131, May 18, 2000.Blank spaces have been verified and no data is available due to changes in the monitoring program.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.(b) Water Quality Objective for metals are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(e) USEPA has not published an aquatic life criterion value.Shaded text – exceeds water quality objective.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.* Indicates detection limit exceeds water quality objective.USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Table 3 - Parameter benchmark values.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-7 4.2.2 Relationships/Analyses The samples collected at this site were not analyzed for the bacterial indicators total coliform, fecal coliform, and enterococcus in 2001-02; and were analyzed using methods that quantify only up to 1,600 MPN/100 mL in 2002-03. Further, the samples collected at this site had detection limits for some analytes that were different than the detection limits obtained in the rest of the program. The incompatibility of detection limits between this station and other stations in the program makes historical statistical data analysis difficult to accomplish. However, results from the most recent season (2003- 2004) conform to detection limits of other mass loading stations within San Diego County. During the three year monitoring period, fecal coliform concentrations exceeded the WQO in 100% of the storms monitored. Chemical oxygen demand and total dissolved solid concentrations exceeded WQO during two of the five storms (40%) monitored. Exceedances for total suspended solids and turbidity were noted during three of the five storms monitored (60%). There were also single exceedances noted for Chlorpyrifos and total copper (20%). From 2001-2004, toxicity was detected during two storm events (See Section 3.1.6.2 for details on toxicity testing). Results from the chi-square analysis (described in Sections 3.5 and 3.6) showed only a significant relationship (p=0.025) between Ceriodaphnia reproduction and chemical oxygen demand (COD). COD concentrations were only above the water quality objective of 120 mg/L during the same two events that toxicity was detected. In order to illustrate the magnitude of the water quality exceedances, the mean ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern from October 2001 through April 2004. The results are shown in Figure 4-2. The largest average exceedances were for TSS and Turbidity, which exceeded the WQO by approximately 7.5 and 15 times, respectively. Another notable mean exceedance was for fecal coliform, which exceeded the WQO by 3.1 times. Dry weather data can be useful to find the sources of contamination. If similar constituents exceed water quality objectives in both dry and wet weather monitoring, then there is evidence that specific sources are creating pollution that is later being washed down the watershed during storms. The latest data for dry weather monitoring provided useful information, taking into account that it only represents one year of monitoring. Thirteen dry weather stations were sampled in this WMA during the 2004 dry weather monitoring program all of which were located above the MLS (See Section 3.4 for details on dry weather sampling). Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-8 TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 15 Ratio to WQOMean Ratio (Oct 01 to Apr 04)Above WQO Figure 4-2. Santa Margarita River water quality ratios. Table 4-4 shows exceedances for constituents that were measured during the 2004 dry weather monitoring program. Dry weather exceedances occurred for nitrate, turbidity, and oil and grease. The only common COC between the dry and wet weather programs was turbidity, although there was only one dry weather turbidity exceedance. A map for the WMA showing dry weather exceedances is found in Figure 4-3. Pie symbols appear at dry weather stations that have had water quality objective exceedances. The colored slices of the pie show the different constituent groups that contributed to the exceedances. All dry weather sample sites were located in natural or earthen channels. Table 4-4. Santa Margarita River WMA 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* St. Dev. Ratio of Exceedance Turbidity 1 9 0.37 0.50 Nitrate 6 13 1.0 0.92 Oil and Grease 1 11 0.63 1.83 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-9 Figure 4-3. Santa Margarita River WMA dry weather exceedance map. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-10 4.2.3 TIEs The absence of toxicity in the Santa Margarita River storm water samples excluded the need for TIE testing. 4.2.4 Summary and Conclusions Concentrations of nutrients and metals in storm water were relatively low. A more complete assessment will be possible in future years as the limited water quality information in the watershed is expanded. 4.3 Stream Bioassessment Stream bioassessment monitoring in the Santa Margarita River WMA included two urban affected sites in Santa Margarita River proper, as well as two reference sites in the upper tributaries. Two sites on the Santa Margarita River have been established, one along Willow Glen Road, and one on Camp Pendleton near the military base hospital. De Luz Creek and Sandia Creek, north of Fallbrook, are considered good reference creeks because the elevation of these sites is between 400 and 600 feet, which is similar to most of the urban affected monitoring sites in the San Diego County program. One site in De Luz Creek on De Luz/Murietta Road was sampled in October 2004, and a site in Sandia Creek on Sandia Creek Road was sampled in October 2004 and May 2005. Storm water mass loading station information was not collected in this watershed during 2004-2005. 4.3.1 Results and Discussion Willow Glen Road Monitoring Site: SMR-WGR The Santa Margarita River bioassessment test site at Willow Glen Road supported a benthic macroinvertebrate community with an IBI score that was rated Poor for both October 2004 and May 2005 (Table 4-5) (See Section 3.2 for details on the bioassessment sampling approach). Overall taxa richness was seasonally variable, and ranged from 21 to 11 unique taxa, with 8 and 4 different EPT taxa collected. A small but very relevant number of intolerant (tolerance value 0, 1, or 2) organisms comprised one percent of the community in the October survey. The percent tolerant taxa comprised four percent of the community in October, and were absent in May. The physical habitat of the site was optimal, with good stream flow velocity and a complex substrate of stable cobble and boulder, and a largely undisturbed riparian zone of oak, sycamore, and willow. Water quality was good with specific conductance values ranging from 1.224 mS/cm in October 2004 to 0.952 mS/cm in May 2005. pH values were 7.8 and 8.4 in the October and May surveys, respectively. The benthic community was dominated in the October survey by the Hydropsychid caddisflies, Hydropsyche and Cheumatopsyche, and the minnow mayfly Baetis (Table 4-6). The highly intolerant caddisfly, Tinodes, were collected in October, as well as several individuals of the sensitive caddisfly, Oxyethira. In the May survey, the benthic community was dominated by the minnow mayfly, Baetis, the black fly, Simulium, and Chironomid midges. The percent of Hydropsychid caddisflies decreased from Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-11 50% of the community in October to less than 1% in May, likely due to heavy filamentous algae covering most of the exposed rocky substrate. Table 4-5. Selected Biological Metrics and Physical Measures of the Santa Margarita River WMA. Santa Margarita Watershed Management Area Santa Margarita River at Willow Glen Road (SMR-WGR) Santa Margarita River on Camp Pendleton (SMR-CP) De Luz Creek Reference Site on De Luz/Murietta Road (REF-DLC3) Sandia Creek Reference Site on De Luz Road (REF-SC2) Survey Oct-04 May-05 Dec-04 May-05 Oct-04 Oct-04 May-05 20 Poor 17 Poor 15 Poor 24 Poor 50 Good 48 Good 25 Poor Metrics Taxa Richness 21 11 13 17 32 27 24 EPT Taxa (mayflies, stoneflies, and caddisflies) 8 4 5 5 11 8 7 % Intolerant Taxa 1% 0% 0% 0% 26% 23% 4% % Tolerant Taxa 4% 0% 2% 1% 3% 1% 3% Average Tolerance Value 5.0 5.3 5.7 5.0 4.0 4.1 5.2 % Collector Filterers +Collector Gatherers 89% 99% 98% 97% 53% 52% 90% Physical Measures Elevation 500 110 540 440 Physical Habitat Score 176 162 155 153 173 166 161 Riffle Velocity (ft/sec) 1.6 2.8 1.9 2.9 3.1 3.2 2.5 Substrate Composition Silt Sand 23 15% 10% 20% 7% 10% 3% Gravel 23% 7% 23% 17% 12% 12% 23% Cobble 44% 53% 52 33% 58% 65% 54% Boulder 3% 25% 15 30% 20% 13% 20% Bedrock/Solid 7% (roots) 3% Water Quality Temperature ºC 19.1 24.6 12.6 23.1 13.7 14.0 15.5 pH 7.8 8.4 7.7 8.4 7.4 8.2 7.7 Specific Conductance (ms/cm) 1.224 0.952 1.461 1.006 1.655 1.944 1.185 Relative Chlorophyll (μg/L) 1.0 2.0 1.1 0.3 2.3 2.4 0.5 Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-12 Table 4-6. Santa Margarita River WMA Community Summary. Taxon Common Name Percent Composition Tolerance Value Functional Feeding Group Hydropsyche net-spinning caddisfly 32% 4 Collector Filterer Cheumatopsyche net-spinning caddisfly 18% 5 Collector Filterer Baetis minnow mayfly 17% 5 Collector Gatherer Chironomidae non-biting midges 15% 6 Collector Gatherer/Filterer Oct-04 Simulium black fly 3% 6 Collector Filterer Baetis minnow mayfly 53% 5 Collector Gatherer Simulium black fly 22% 6 Collector Filterer Chironomidae non-biting midges 14% 6 Collector Gatherer/Filterer Fallceon quilleri minnow mayfly 7% 4 Collector Gatherer Santa Margarita River at Willow Glen Road (SMR-WGR) May-05 Oligochaeta earthworms 2% 5 Collector Gatherer Simulium black fly 62% 6 Collector Filterer Baetis minnow mayfly 19% 5 Collector Gatherer Chironomidae non-biting midges 8% 6 Collector Gatherer/Filterer Fallceon quilleri minnow mayfly 6% 4 Collector Gatherer Oct-04 Sperchon water mite 1% 5 Predator Fallceon quilleri minnow mayfly 37% 4 Collector Gatherer Simulium black fly 25% 6 Collector Filterer Baetis minnow mayfly 16% 5 Collector Gatherer Chronomidae non-biting midges 11% 6 Collector Gatherer/Filterer Santa Margarita River on Camp Pendleton (SMR-CP) May-05 Hydropsyche net-spinning caddisfly 2% 4 Collector Filterer Hydropsyche net-spinning caddisfly 22% 4 Collector Filterer Micrasema humpless casemaker caddisfly 18% 1 Macrophyte Herbivore Zaitzevia riffle beetle 14% 4 Scraper Argia dancer damselfly 11% 7 Predator Oct-04 Cheumatopsyche net-spinning caddisfly 8% 5 Collector Filterer Baetis minnow mayfly 32% 5 Collector Gatherer Chronomidae non-biting midges 26% 6 Collector Gatherer/Filterer Hydropsyche net-spinning caddisfly 17% 4 Collector Filterer Simulium black fly 10% 6 Collector Filterer Sandia Creek Reference Site at De Luz Road (REF-SC2) May-05 Oligochaeta earthworms 4% 5 Collector Gatherer Micrasema humpless casemaker caddisfly 22% 1 Macrophyte Herbivore Hydropsyche net-spinning caddisfly 21% 4 Collector Filterer Zaitzevia riffle beetle 12% 4 Scraper Baetis minnow mayfly 11% 5 Collector Gatherer De Luz Creek Reference Site on De Luz/Murietta Road (REF-DLC3) Oct-04 Simulium black fly 10% 6 Collector Filterer Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-13 Camp Pendleton Monitoring Site: SMR-CP The monitoring site on Camp Pendleton was rated similar to the Willow Glen Road site, with quality ratings of Poor for both surveys (Table 4-5). There were 13 and 17 different taxa of macroinvertebrates collected in October 2004 and May 2005, respectively, which was a decrease from the previous year when the site had the greatest taxa richness of any of the urban affected (non reference) sites in the San Diego County program (MEC-Weston 2005). The in-stream physical habitat of the sampling transects was different than in previous surveys. The heavy rains of 2004-2005 had scoured much of the sand from a portion of the reach, exposing a large area of cobble and boulder substrate. The overall river course is relatively undisturbed with a good willow dominated riparian zone. Water quality was good with specific conductance ranging from 1.461 to 1.006 ms/cm and pH ranging from 7.7 to 8.4 in October 2004 and May 2005, respectively. The benthic community was dominated in both surveys by the minnow mayflies, Fallceon quilleri and Baetis; the black fly, Simulium; and Chironomid midges (Table 4-6). There were five different EPT taxa collected in both surveys. Two genera of riffle beetles were collected at the site, including Heterelmis in October and Microcylloepus in May, and this was the only non reference site in the program where riffle beetles were collected. De Luz Creek Reference Site: REF-DLC3 The De Luz Creek reference monitoring site had a benthic community with an Index of Biotic Integrity quality rating of Good in the October 2004 survey (Table 4-5). There were 32 different taxa collected, with 11 different EPT taxa. Organisms that are highly intolerant to impairment accounted for 26% of the community, and the average tolerance value was relatively low at 4.0. The riparian zone was dominated by oak and sycamore and the reach had good in-stream characteristics, with diverse microhabitats suitable for macroinvertebrate colonization. Stream flow and current velocity is generally good year-round, even after the extended dry period of 2004. Specific conductance was similar to past years surveys (MEC-Weston 2005) and was relatively high compared to most reference sites, with a value of 1.655 ms/cm (Table 4-5). The benthic community was dominated by the highly intolerant caddisfly, Micrasema (Table 4-6). The net-spinning caddisfly, Hydropsyche, was also abundant. There were numerous taxa collected at this site that were collected only at other reference sites, including Zaitzevia, Malenka, Helichus, Helicopsyche borealis, and Nectosphyche. Sandia Creek Reference Site: REF-SC2 The Sandia Creek reference monitoring site had a benthic community with an Index of Biotic Integrity quality rating of Good in the October 2004 survey, and Poor in the May 2005 survey (Table 4-5). The IBI score for May was one point higher than the highest rated urban influenced site, Santa Margarita River on Camp Pendleton. There were 27 and 24 different taxa collected, with 8 and 7 different EPT taxa in October 2004 and May 2005, respectively. Organisms that are highly intolerant to impairment accounted for 23% in October 2004 and 4% of the community in May 2005. The average tolerance value was 4.1 and 5.2 for the October and May surveys, respectively. The stream habitat was similar to the De Luz Creek reference site, with an oak and sycamore riparian zone and complex in-stream characteristics. Field biologists have noticed increasing removal of native oak trees and the planting of avocado groves upstream of the site. Specific conductance values were Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-14 1.944 and 1.185 ms/cm and pH values were 8.2 and 7.7 for the October 2004 and May 2005 surveys, respectively. The benthic community was variable between the two surveys. For the October survey, the site was dominated by the net-spinning caddisfly, Hydropsyche, and the highly intolerant caddisfly, Micrasema (Table 4-6). The riffle beetle, Zaitzevia, and the damselfly, Argia, were also abundant. For the May survey, the dominant taxa included the minnow mayfly, Baetis, Chironomid midges, and Hydrospyche. Like the other two reference sites, there were a number of intolerant taxa collected that were unique to the site. 4.3.2 Summary and Conclusions The Santa Margarita River WMA was sampled at a total of four monitoring sites, including reference sites in De Luz Creek and Sandia Creek. All of the sites had mostly undisturbed conditions, and the Index of Biotic Integrity quality ratings ranged from Poor to Good. As in past surveys, the monitoring sites in Santa Margarita River were among the highest rated of the urban affected sites in San Diego County, although the IBI scores in May 2005 were lower than usual. Biological metric values and water quality measures indicated that this watershed is one of the least impacted in San Diego County. 4.4 Ambient Bay and Lagoon Monitoring Program 4.4.1 Results and Discussion for Santa Margarita River Estuary There are two coastal embayments in the Santa Margarita River WMA that were monitored in the ABLM Program: Santa Margarita River Estuary and Oceanside Harbor. 4.4.1.1 Phase I Results and Discussion for Santa Margarita River Estuary Sediment samples were collected in Santa Margarita River Estuary for the ABLM Program on June 15, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 4-4. Santa Margarita River Estuary was unique among the 12 embayments sampled in Phase I. The nine sites sampled in Santa Margarita River Estuary had the second highest median grain size (190 μm), the lowest percent fines (5.63%), and the lowest TOC content (0.13%) of any of the twelve embayments assessed (Table 4- 7). Sand was the dominant sediment constituent at all of the nine sites sampled in Santa Margarita River Estuary, accounting for at least 86.3% of the grain size distribution. Figure 4-4. Map of Phase I site locations in Santa Margarita River Estuary. Sites with yellow triangles were selected for Phase II assessment. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-15 Sites 2M-1 and 2R-2 in the middle stratum and Site 1R-1 near the mouth of the Estuary were selected for Phase II assessment (Table 4-7). Site 3R-3 also had a high TOC content but it had a lower percentage of fine sediments than the other sites chosen. Table 4-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Santa Margarita River Estuary. Grain Size Distribution and TOC in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II SME-1L-2 0.00 96.2 1.42 2.35 168 168 3.77 0.07 5 2 7 SME-1M-1 0.00 97.8 1.36 0.88 182 187 2.24 0.05 1 1 2 SME-1R-1 0.06 95.5 2.81 1.62 177 201 4.43 0.10 7 6 13 * Yes SME-2L-1 0.00 97.4 0.57 2.05 185 191 2.62 0.09 2 5 7 SME-2M-1 0.33 86.3 7.52 5.85 136 133 13.37 0.28 8 9 17 * Yes SME-2R-2 0.00 86.3 9.3 4.4 99.5 97.8 13.73 0.25 9 8 17 * Yes SME-3L-1 0.09 96.7 1.27 1.97 274 277 3.24 0.08 4 4 8 SME-3M-1 0.00 97.0 0.85 2.12 193 187 2.97 0.07 3 3 6 SME-3R-3 0.19 95.5 1.73 2.58 295 302 4.31 0.17 6 7 13 * Mean of all Sites 0.08 94.29 2.98 2.65 190.00 193.66 5.63 0.13 St. Dev. 0.12 4.60 3.17 1.53 61.17 63.60 4.55 0.08 4.4.1.2 Phase II Results and Discussion for Santa Margarita River Estuary The three sites selected in the Santa Margarita River Estuary as part of Phase I were sampled in Phase II on July 15, 2004. Sediments from Sites 1R-1, 2M-1 and 2R-2 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 4-8. Table 4-8. Summary of chemistry, toxicity, and benthic community structure in Santa Margarita River Estuary. CHEMISTRY* TOXICITY*BENTHIC COMMUNITY Analyte ERL ERM Result ERM-Q Percent Survival Index 1R-1 2M-1 2R-2 Mean St. Dev.Total METALS (mg/kg) Abundance 198 116 109 141 49.5 423 Antimony NA NA <1.74 NA Richness 15 8 10 11 3.61 18 Arsenic 8.2 70 1.67 0.024 Diversity 1.67 1.67 1.84 1.73 0.10 NA Cadmium 1.2 9.6 <0.174 NA Evenness 0.62 0.80 0.80 0.74 0.10 NA Chromium 81 370 13.2 0.036 Dominance 3 4 4 3.67 0.58 NA Copper 34 270 6.45 0.024 Lead 46.7 218 5.13 0.024 Nickel 20.9 51.6 4.92 0.095 Selenium NA NA <1.74 NA Zinc 150 410 37.2 0.091 Mean ERM-Q 0.049 97% Not Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-16 Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these only six metals were detected above the detection limit in sediments from the Santa Margarita River Estuary: arsenic, chromium, copper, lead, nickel, and zinc (Table 4-8). All concentrations were very low and none exceeded the ERL or the ERM. Thus, the mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was also very low (0.049). The same six metals were detected above detection limits during the 2003 ABLM program which also had a very low mean ERM quotient (0.05). There were no PAHs, PCBs, or pesticides found above the detection limit in Santa Margarita River Estuary. The mean ERM-Q for Santa Margarita River Estuary was the lowest of any of the 12 embayments assessed in the ABLM Program and well below the threshold of 0.10. This estuary also had the lowest ERM-Q value during the 2003 ABLM program. Sediments with mean ERM-Q values below this threshold have a low probability of producing adverse biological effects (Long et al. 1998). Toxicity. The percent survival of E. estuarius exposed to Santa Margarita River sediments in a 10-day acute toxicity test was 97% (Table 4-8). Percent survival was not significantly different from that of the Control (99%), suggesting that Santa Margarita River Estuary sediments were not toxic to the test organisms. This is similar to the results from the 2003 ABLM program where no toxicity was observed. Benthic Community Structure. A total of 423 organisms were collected from Santa Margarita River Estuary, representing 18 taxa (Table 4-8). Taxa abundance and richness were higher at Site 1R-1 at the mouth of the Estuary than the other two sites, but diversity and evenness were lower. Dominance was close to the same at all sites (3,4,4). Based on these indices, the benthic community structure had a rank of 5, where 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. During the 2003 ABLM program a total of 529 organisms were collected, representing 16 taxa. One species dominated the infaunal community in Santa Margarita River Estuary: Cerithidea californica, the California Horn Snail, which accounted for 28.6% of all the animals collected (Table 4-9). Probably the most common snail in southern California lagoon mudflats, Cerithidea is highly tolerant to temperature and salinity fluxes. The polychaete worm, Pseudopolydora paucibranchiata, was the second most common species found in Santa Margarita River Estuary, followed by the gammarid amphipod, Grandidierella japonica. During the 2003 ABLM program, Grandidierella japonica dominated the infaunal community and accounted for 63.7% of all animals collected. Table 4-9. Dominant infaunal species found in the Santa Margarita River Estuary during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Cerithidea californica Mollusc 121 28.6 Pseudopolydora paucibranchiata Polychaete 100 23.6 SME Grandidierella japonica Crustacean 79 18.7 Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-17 Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Santa Margarita River Estuary were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 4-5. For Santa Margarita River Estuary, the relative ranks were one for chemistry, two for toxicity and five for benthic community structure. 4.4.1.3 Summary and Conclusions for Santa Margarita River Estuary Sediments in Santa Margarita River Estuary were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grain size): site 1R-1 in the outer stratum of the Estuary and sites 2M-1 and 2R-2 in the middle stratum. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that only six metals were found in the Estuary sediments, all at very low concentrations. Sediment toxicity was also low and not significantly different from that of a Control sample. Benthic community indices suggested that biotic community in the Estuary sediments were similar to other embayments in the County and was dominated by a gastropod and polychaete worms. Compared to the other embayments in San Diego County, the relative ranks for Santa Margarita River Estuary were one for chemistry, two for toxicity and five for benthos. Compared to the other embayments in the 2004 ABLM program, Santa Margarita River Estuary had an overall rank of one. During the 2003 ABLM program the Estuary had an overall rank of two. The decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 0 1 2 3 4 5 6 Chemistry Toxicity Benthos RankingFigure 4-5. Relative rankings for sediment in Santa Margarita River Estuary. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-18 4.4.2 Results and Discussion for Oceanside Harbor 4.4.2.1 Phase I Results and Discussion for Oceanside Harbor Sediment samples were collected in Oceanside Harbor for the ABLM Program on June 9, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 4-6. Unlike all the other sites assessed in Phase I, although storm drains discharge to Oceanside Harbor, it has no direct freshwater input from a major watershed. Therefore, the inner stratum was designated as the area farthest from the harbor breakwaters, which included all of the boat slips in North and South Harbor. The middle and outer strata roughly divide the main basin. The area north of the main basin is located on military property and was inaccessible at the time of the survey. All three of the inner stratum sites had much smaller median grain sizes and a larger proportion of fine sediments than any of the sites in the middle and outer strata. (Table 4-10) The inner strata sites also had higher TOC levels than the other sites. This pattern was particularly clear at Sites 3M-1 and 3R-1 (which are located in the south boat basin). Tidal flushing is most likely limited in this area, allowing for the deposition of fine-grained, high TOC sediments. All three sites in the inner strata of Oceanside Harbor (3L-1, 3M-1, 3R-1) were selected for Phase II assessment. Table 4-10. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Oceanside Harbor. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II OH-1L-1 0.29 98.0 0.94 0.79 149 151 1.72 0.06 1 1 2 OH-1M-1 0.00 87.3 9.9 2.77 92.9 89.7 12.69 0.23 5 4 9 OH-1R-1 0.00 79.3 15.20 5.47 115 70 20.66 0.38 6 6 12 OH-2L-1 0.29 94.5 2.85 2.40 113 116 5.25 0.24 2 5 7 OH-2M-1 0.50 92.7 5.68 1.12 99 102 6.80 0.12 3 3 6 OH-2R-2 0.27 89.0 9.30 1.42 92 121 10.71 0.11 4 2 6 OH-3L-1 0.04 37.0 39.6 23.3 26.0 14.9 62.91 1.07 7 8 15 * Yes OH-3M-1 0.07 11.0 62.3 26.7 12.7 7.48 88.96 1.29 9 9 18 * Yes OH-3R-1 0.01 36.5 41.5 22.0 28.4 14.29 63.45 0.77 8 7 15 * Yes Mean of all Sites 0.16 69.48 20.81 9.54 80.98 76.20 30.35 0.47 St. Dev. 0.18 32.28 21.60 10.99 47.23 52.90 32.38 0.46 Figure 4-6. Map of Phase I site locations in Oceanside Harbor. Sites with yellow triangles were selected for Phase II assessment. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-19 4.4.2.2 Phase II Results and Discussion for Oceanside Harbor The three sites selected in the Oceanside Harbor as part of Phase I were sampled in Phase II on July 14, 2004. Sediments from Sites 3L-1, 3M-1 and 3R-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 4-11. Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, seven metals were detected above the detection limit in sediments from Oceanside Harbor in 2004: arsenic, chromium, copper, lead, nickel, selenium and zinc (Table 4-11). All concentrations were low and none exceeded the ERM during 2004. However, concentrations of copper and zinc exceeded their respective ERLs. With the exception of selenium, the same metals were detected above the detection limit during the 2003 ABLM program. All metal concentrations were low and did not exceed the ERM during 2003, however copper and zinc did exceed their respective ERLs. Table 4-11. Summary of chemistry, toxicity, and benthic community structure in Oceanside Harbor. CHEMISTRY* TOXICITY* BENTHIC COMMUNITY Analyte ERL ERM Result ERM- Q Percent Survival Index 3L- 1 3M-1 3R-1 Mean St. Dev. Total METALS (mg/kg) Abundance 495 298 223 338.7 140.5 1016 Antimony NA NA <1.74 NA Richness 39 46 37 40.67 4.73 75 Arsenic 8.2 70 8.15 0.116 Diversity 2.45 3.10 2.86 2.80 0.33 NA Cadmium 1.2 9.6 <.174 NA Evenness 0.67 0.81 0.79 0.76 0.08 NA Chromium 81 370 42.2 0.114 Dominance 7 12 10 9.67 2.52 NA Copper 34 270 116 0.430 Lead 46.7 218 19.6 0.090 Nickel 20.9 51.6 15 0.291 Selenium NA NA 1.63 NA Zinc 150 410 177 0.432 Mean ERM-Q 0.245 86% Not Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value During 2004, Oceanside Harbor was one of only three sites assessed where selenium was found in the sediments (Mission Bay and Los Peñasquitos were the other two sites). There were no PAHs, PCBs, or pesticides found above the detection limit in Oceanside Harbor. During the 2003 ABLM program Oceanside Harbor was one of only two sites assessed where PAHs were found in the sediments. The concentrations of all four PAHs found last year were low and well below their respective ERLs. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was low for all sites assessed in 2004 when compared to published values (Long et al. 1998). The mean ERM-Q for Oceanside Harbor was 0.245, which exceeded the threshold of 0.10. Sediments with mean ERM-Q values above this threshold have a greater probability of producing adverse biological effects than embayments with mean ERM-Qs below the threshold (Long et al. 1998). Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-20 Toxicity. The percent survival of E. estuarius exposed to Oceanside Harbor sediments in a 10-day acute toxicity test was 86 % (Table 4-11). Percent survival was not significantly different from that of the Control (99%), suggesting that Oceanside Harbor sediments were not toxic to the test organisms. During the 2003 ABLM program toxicity was detected, but the source of the toxicity was unknown. Benthic Community Structure. A total of 1016 organisms were collected from Oceanside Harbor, representing 75 taxa (Table 4-11). Taxa abundance at Oceanside Harbor was similar to other embayments assessed, but taxa richness was among the highest, second to Mission Bay and slightly ahead of Sweetwater River Estuary. This is similar to the 2003 ABLM program where Oceanside Harbor was also among the top three sites for taxa richness with 522 organisms collected representing 55 taxa. Among the three sites assessed in Oceanside Harbor during 2004, Site 3L-1 had the greatest abundance, but Site 3M-1 had the greatest richness, diversity, evenness, and dominance (Table 4-11). The benthic community of Oceanside Harbor ranked high among the other ABLM sites in species diversity and richness (1 and 2 respectively), but low in abundance (9). Based on these indices, the benthic community structure in Oceanside Harbor received a ranking of two, which was the second highest among the embayments assessed in the 2004 ABLM Program (see Section 13.5 for a complete discussion). A rank of 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. Similar to the 2003 ABLM program, polychaete worms dominated the infaunal community in Oceanside Harbor during the 2004 ABLM program. Scoletoma sp and Pseudopolydora paucibranchiata each accounted for 18.9% of all the animals collected (Table 4-12). The polychaete worm, Euchone limnicola, was the next most abundant taxa, accounting for 5.9% of the community. During the 2003 ABLM program Pseudopolydora paucibranchiata dominated the infaunal community and accounted for 51.3% of all the animals collected. Table 4-12. Dominant infaunal species found in Oceanside Harbor during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Scoletoma sp Polychaete 193 18.9 Pseudopolydora paucibranchiata Polychaete 192 18.9 OH Euchone limnicola Polychaete 60 5.9 Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Oceanside Harbor were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 4-7. For Oceanside Harbor, the relative ranks were 10 for chemistry, 6 for toxicity, and 2 for benthic community structure. 0 2 4 6 8 10 12 Chemistry Toxicity Benthos RankingFigure 4-7. Relative rankings for sediment in Oceanside Harbor. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-21 4.4.2.3 Summary and Conclusions for Oceanside Harbor Sediments in Oceanside Harbor were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grain size). All three sites were located in the inner Harbor. In Phase II of the assessment these sites were analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven metals were found in the Harbor sediments. All of the COC were found at low concentrations, except copper and zinc, which were slightly elevated. Percent survival of test organisms exposed to Oceanside Harbor sediments was 86%, which was not significantly different from that of the Control. The benthic community in Oceanside Harbor ranked second highest among the embayments assessed in the ABLM Program based on benthic community indices. The community was dominated by polychaete worms, especially Scoletoma sp. and the tube building polychaete, Pseudopolydora paucibranchiata. For Oceanside Harbor, the relative ranks were 10 for chemistry, 6 for toxicity, and 2 for benthos. Compared to the other embayments in the 2004 ABLM program, Oceanside Harbor had an overall rank of six. During the 2003 ABLM program the Harbor had an overall rank of seven. The decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 4.5 WMA Assessment The Santa Margarita watershed was assessed in order to identify water quality issues within the watershed and to develop short and long-term planning actions to address these issues. The assessment included chemistry and toxicity data collected during storm events from a MLS on Santa Margarita River, chemistry data collected during dry weather, and stream bioassessment IBI ratings. Constituent of concern criteria were developed to prioritize COC for each watershed. The watershed management area assessment methods, discussed in Section 3.4, were applied to these data to determine the constituents of concern and to develop a frequency of occurrence ranking (high, medium, or low). Constituent exceedances in wet and dry weather are summarized in Table 4-13. The cumulative column shows the frequency of occurrence from the 2001-2002 storm season through the 2003-2004 storm season. Wet weather sampling was not conducted during the 2004-2005 storm season, however dry weather sampling and stream bioassessment were conducted during 2004-2005. The IBI rating was assigned based on the average of the IBI scores of non-reference bioassessment sites in the watershed. In the Santa Margarita River, two constituents were identified as having a high frequency of occurrence and received three diamonds. These constituents include: • Fecal Coliform • Turbidity Fecal coliform received three diamonds based on Criterion No. 1 and turbidity received three diamonds based on Criterion No. 3. One constituent had a medium frequency of occurrence and was assigned two diamonds based on Criterion No. 5. This constituent was: • Total suspended solids Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-22 Table 4-13. Constituent exceedances in the Santa Margarita River WMA. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/1 % #/2 % #/2 % # % #/5 % # % Frequency of Occurrence Criterion No. Conventional Parameters Oil and Grease 0 0 0 0 0 0 NA NA 0 0 1 9 - - COD 0 0 2 100 0 0 NA NA 2 40 NA NA - - Total Dissolved Solids 1 100 0 0 1 50 NA NA 2 40 NA NA ♦ 9 Total Suspended Solids 0 0 2 100 1 50 NA NA 3 60 NA NA ♦♦ 5 Turbidity 0 0 2 100 1 50 NA NA 3 60 1 11 ♦♦♦ 3 Nutrients Nitrate as N 0 0 0 0 0 0 NA NA 0 0 6 46 ♦ 8 Bacteriological Fecal Coliform NA NA 2 100 2 100 NA NA 4 100 0 0 ♦♦♦ 1 Pesticides Chlorpyrifos 0 0 0 0 1 50 NA NA 1 20 NA NA - - Total Metals Chromium 0 0 2 100 0 0 NA NA 2 40 NA NA - - Copper 0 0 1 50 0 0 NA NA 1 20 NA NA - - Zinc 0 0 1 50 0 0 NA NA 1 20 NA NA - - Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 7-day reproduction 0 0 2 100 0 0 NA NA 2 40 NA NA No Hyalella 96-hour 0 0 1 50 0 0 NA NA 1 20 NA NA No Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? Santa Margarita River at Willow Glen Rd. NA Poor Fair Poor Poor NA Santa Margarita River, Camp Pendleton (DS) NA Poor Fair Poor Poor NA No * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS Two constituents were identified as having a low frequency of occurrence and assigned one diamond. These constituents include: • Total dissolved solids • Nitrate During the 2002-2003 storm season, there were exceedances of chemical oxygen demand, total chromium, copper, and zinc concentrations and there was evidence of toxicity, however there were no exceedances of these constituents or toxicity present during the 2001-2002 and 2003-2004 seasons. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-23 Persistent toxicity is evident when more than 50% of the toxicity tests conducted on any species have a NOEC of less than 100%. Even though there was evidence of toxicity during the 2002-2003 storm season, there was no evidence of persistent toxicity in the Santa Margarita River watershed throughout the duration of the monitoring period. IBI scores from bioassessment monitoring from two sites in the Santa Margarita River have varied between poor and fair conditions throughout the monitoring period. These results indicate that there is no evidence of benthic alteration. Even though the Santa Margarita River benthic communities were rated as poor, the habitats were generally ranked as the best in San Diego County. Figure 4-8 illustrates the number of wet weather exceedances for each monitoring season for six categories of constituents, including conventional parameters, nutrients, bacteria, pesticides, metals and toxicity. The stacked bar charts were developed using the number of exceedances from values in Table 4-13 for each constituent category. This displays a conceptual picture of water quality concerns in the watershed over time. The overall number of exceedances of water quality objectives for the Santa Margarita River watershed was the lowest during 2001-2002 and highest during 2002-2003. Conventional parameters, such as TSS and turbidity, constituted the most number of exceedances for all three monitoring seasons. During 2003-2004, bacteriological parameters constituted the second highest number of exceedances while metal constituents made up the second highest number of exceedances during the 2002-2003 season. Santa Margarita River Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 4-8. Stacked bar chart of the number of wet weather exceedances of constituent groups in Santa Margarita River. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-24 Triad Decision Matrix The data from wet and dry weather, toxicity and bioassessment monitoring efforts were evaluated for this watershed using the triad decision matrix. The triad decision matrix incorporates the chemistry data from wet and dry weather events with the toxicity and bioassessment results to provide indications of pollutant loading, potential impacts to organisms and the ecological health of the watershed. The triad assessment presents possible conclusions about the watershed and provides possible actions or decisions for future monitoring and assessment. Table 4-14 summarizes these results. Table 4-14. Decision matrix results for Santa Margarita River WMA. Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions Persistent exceedances of water quality objectives (high frequency COC identified) No persistent evidence of toxicity No Indications of alteration Limited dataset makes conclusions difficult. Test organisms not sensitive to problem pollutants. Contaminants are not bioavailable. 1) Continue monitoring to gather long-term trend information. 2) Continue monitoring for toxic and benthic impacts. Consider whether different or additional test organisms should be evaluated. 3) Initiate upstream source identification as a low priority. 4) TIE would not provide useful information with no evidence of toxicity. Based on the triad matrix, there was evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and no indications of benthic alteration. The recommended actions for the Santa Margarita River watershed are to continue monitoring for all elements of the program to gather additional data for assessment and long-term trend analysis, continue monitoring for toxic and benthic impacts and to initiate upstream source identification to determine sources of constituents of concern. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Santa Margarita River WMA The water quality priority ratings presented in Table 4-15 are based on the methodology presented in the BLTEA report (WESTON, MOE, & LWA 2005) and are presented in the Methods Section 3.4. Constituent groups and stressor groups are given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicate that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on current results presented in this 2004-2005 annual report and data from the following programs: • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Co-permittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303d Listing Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-25 Table 4-15. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Santa Margarita River WMA. Priority Ratings* Constituent Groups Stressor Groups Watersheds/Sub- watersheds Percentage of Total Area Heavy Metals Organics Oil and Grease Sediments Pesticides Nutrients Gross Pollutants Bacteria/ Pathogens Benthic Alterations Toxicity Santa Margarita WMA 100% C D D A C B B B B C Ysidora HA (902.10) 11% D D D A C A C A B C DeLuz HA (902.20) 29% D D D A C A C C B C Pechanga HA (902.50) 12% C D D B D A B B B C Aguanga HA (902.80) 28% C D D B D D B B B C Oakgrove HA (902.90) 20% C D D B D D B B B C Notes: * = Rating Calculated Based on Area Weighted Averages of Score Value from the sub-watershed areas. ** = Priority Level (Highest-A to Lowest-D) The purpose of the BLTEA ratings is to identify water quality priorities within a watershed based on weighted averages of the sub-watershed ratings. Because it is a weighted average, larger sub-watersheds will have a greater influence in the overall watershed rating. Sediment was rated as the highest priority constituent (A) overall for the Santa Margarita River WMA, followed by nutrients, gross pollutants, bacteria, and benthic alterations which were all given a B rating. All other constituent groups or stressors were given a C or D rating. The Ysidora sub-watershed which accounts for 11% of the total Santa Margarita River WMA had high priority (A) ratings for sediments, nutrients, and bacteria. The DeLuz sub-watershed which accounts for 29% of the total Santa Margarita River WMA had high priority (A) ratings for sediments and nutrients. The Pechanga sub-watershed which accounts for 12% of the total Santa Margarita River WMA, had a high priority (A) rating only for nutrients. The Aguanga sub-watershed, which accounts for 28%, and the Oakgrove sub-watershed, which accounts for 20%, did not have any high priority (A) ratings for any constituent group. All of the sub-watersheds had B ratings for benthic alteration. A regional evaluation and description of the BLTEA is presented in the Regional Assessment Section 13. The complete tables used to calculate the ratings are presented in Appendix G. Santa Margarita River WMA SECTION 4 2004-2005 Urban Runoff Monitoring Report 4-26 4.6 Conclusions and Recommendations The Santa Margarita River watershed is the second largest in the San Diego hydrologic region. The primary land use within the contributing runoff area is undeveloped (64%). For the Santa Margarita River WMA, turbidity and fecal coliform were identified as high frequency of occurrence COC, TSS was identified as a medium frequency of occurrence COC, and TDS and nitrate were identified as low frequency of occurrence COC. There was no evidence of persistent toxicity found in Santa Margarita River. The stream habitat quality varied between poor and fair which indicated that there was no evidence of benthic alteration. Based on the Ambient Bay and Lagoon Monitoring Program, the relative ranks for Santa Margarita River Estuary were one for chemistry, two for toxicity and five for benthos. Compared to the other embayments in the 2004 ABLM program, Santa Margarita River Estuary had an overall rank of one. The relative ranks for Oceanside Harbor were 10 for chemistry, 6 for toxicity, and 2 for benthos. The benthic community ranked second highest among other embayments within San Diego County. Compared to the other embayments in the 2004 ABLM program, Oceanside Harbor had an overall rank of six. The relative quality for both Santa Margarita River Estuary and Oceanside Harbor increased from the ABLM 2003 monitoring year. The WMA assessment findings agreed with the BLTEA rating priorities for the Santa Margarita River WMA, which found sediments to be a high priority (A rating) constituent. The BLTEA ratings also gave a B rating to nutrients, bacteria, gross pollutants and benthic alteration. The information provided from the triad matrix results used in conjunction with the BLTEA ratings can assist the jurisdictions in making informed decisions in developing their WURMP programs. The two reports also allow for an evaluation of where data gaps exist and where efforts should be targeted. Utilizing the BLTEA rating methods for future data evaluations would also allow for long- term BMP effectiveness assessment. Incorporation of additional useable data from other third party sources such as publicly owned treatment works (POTWs) or non-profit organizations would also help to increase the confidence of the BLTEA ratings and overall WMA assessments. The recommendations for this watershed are to continue monitoring to determine long-term trends, continue monitoring for toxic and benthic impacts and to identify upstream sources of constituents of concern. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-1 6.0 CARLSBAD WATERSHED MANAGEMENT AREA 6.1 Monitoring Site Descriptions The Carlsbad watershed management area includes the Carlsbad watershed (HU 904.00). This watershed contains six hydrologic areas: Loma Alta, Buena Vista Creek, Agua Hedionda, Encinas, San Marcos, and Escondido Creek. The Carlsbad watershed covers over 135,000 acres and is located entirely within the San Diego Region (Figure 6-1). The majority of the watershed resides in unincorporated areas of San Diego County with some portions found in the following cities: Carlsbad, Encinitas, Escondido, Oceanside, San Marcos, Solana Beach, and Vista. Land use for this watershed consists of residential, commercial/industrial, freeways, agriculture, and vacant/undeveloped areas. Land ownership is primarily private with small percentages of local, state, and federally-owned areas. There are 43,825 acres of vacant/undeveloped land, of which 24,841 acres are available for development. Almost 21,000 acres are being planned for residential development. The Carlsbad watershed is the third most densely populated watershed in the San Diego region and is expected to reach over 700,000 people by 2015 (SANDAG 1998). The Carlsbad watershed with its numerous lagoons provides many beneficial uses including freshwater and estuarine habitats (Table 6-1). Due to high coliform bacteria counts, sediment loading and other pollutants, some lagoons and other water bodies within the watershed have been listed on the SWRCB 2002 303(d) list (Table 6-2). Major impacts to the watershed include surface water quality degradation, beach closures, sedimentation, habitat degradation and loss, invasive species, and eutrophication. The sources of these pollutants are varied including urban runoff, agricultural runoff, sewage spills, and livestock/domestic animals (San Diego County 2001). Annual rainfall over the watershed varies from 10.5 inches near the coast to 19.5 inches in the inland areas (Figure 6-1). Reservoirs in the Carlsbad watershed include Dixon Lake and Lake Wolford. The San Marcos Dam controls approximately 53% of the watershed (Coastal Conservancy 2001). This watershed management area has two monitored mass loading stations, one on Agua Hedionda Creek and one on Escondido Creek. The Agua Hedionda Creek (AHC) mass loading station is located in a natural channel under the El Camino Real Bridge crossing immediately downstream of the confluence of Agua Hedionda Creek and Calavera Creek. Runoff from the Agua Hedionda watershed, including Buena Creek, drains through one main artery to Agua Hedionda Lagoon. The Agua Hedionda watershed is one of two sub-watersheds within the larger Carlsbad watershed management area that has a mass loading station. The contributing runoff area covers over 15,100 acres, which is approximately 11% of the Carlsbad watershed. Land use within the contributing runoff area is primarily residential (33%), undeveloped (25%), and agriculture (11%). The contributing runoff area is representative of the entire watershed which is approximately 32% residential 24% undeveloped, and 9% agricultural. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-2 Figure 6-1. Carlsbad Watershed Management Area. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-3 Table 6-1. Beneficial uses within the Carlsbad watershed. Beneficial Uses Inland Surface Waters Coastal Waters Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z z z Agricultural Supply z z z Industrial Service Supply z z O z Hydropower Generation z z Navigation Contact Water Recreation z z z1 Non-Contact Water Recreation z z z Commercial and Sport Fishing z Biological Habitats of Special Significance z Warm Freshwater Habitat z z z Cold Freshwater Habitat z z Estuarine Habitat z Wildlife Habitat z z z Rare, Threatened, or Endangered Species z z Marine Habitat z Migration of Aquatic Organisms z Aquaculture z Shellfish Harvesting z Spawning, Reproduction and/or Early Development z = Existing O = Potential 1 Shore and boat fishing only. Other REC1 uses prohibited. Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) Table 6-2. Water bodies on the SWRCB 303(d) list in the Carlsbad watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor Pacific Ocean Shoreline Loma Alta 904.10 Bacterial Indicators Loma Alta Slough Loma Alta 904.10 Bacterial Indicators, Eutrophic Pacific Ocean Shoreline Buena Vista Creek 904.21 Bacterial Indicators Buena Vista Lagoon (202 acres) El Salto 904.21 Bacterial Indicators, Nutrients Sedimentation/ Siltation Agua Hedionda Lagoon (7 acres) Los Monos 904.31 Bacterial Indicators, Sedimentation/Siltation Agua Hedionda Creek Los Monos 904.31 TDS Pacific Ocean Shoreline San Marcos 904.51 Bacterial Indicators Pacific Ocean Shoreline Escondido Creek 904.61 Bacteria Indicators San Elijo Lagoon San Elijo 904.61 Bacterial Indicators, Eutrophic, Sedimentation/Siltation Source: SWRCB 2003 Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-4 The Escondido Creek (EC) mass loading station, the second of two mass loading stations located within the Carlsbad watershed management area, is located along a natural channel in Encinitas, east of Rancho Santa Fe Road, under the Camino Del Norte Bridge. The contributing runoff area covers over 44,100 acres on approximately 33% of the Carlsbad watershed. Therefore, this site is partially representative of the Carlsbad watershed. Land use within the contributing runoff area is predominantly undeveloped (35%), residential (25%), and parks (16%). Escondido Creek discharges into San Elijo Lagoon. Stream Bioassessment monitoring has occurred in many of the streams in the Carlsbad WMA including Buena Vista River, Loma Alta Creek, San Marcos Creek, Agua Hedionda Creek, and Escondido Creek. Habitat quality is quite variable throughout the region, and all of the streams maintain year-round flow due to urban input. Buena Vista River near College Boulevard, San Marcos Creek in La Costa Canyon, and Escondido Creek in Elfin Forest all have very high quality in-stream habitats with excellent riffles. These reaches are downstream of substantial urban development, providing very good test sites for runoff impacts. Agua Hedionda Creek has marginal to sub-optimal habitat quality with gravel and sand dominating the substrate. Loma Alta Creek is generally a low gradient stream overgrown with invasive vegetation (e.g., Typha and Arundo) with mostly poor habitat for benthic macroinvertebrates. Monitoring is now focused on Aqua Hedionda Creek (Melrose Drive and El Camino Real overcrossings) and Escondido Creek (Harmony Grove Bridge and in Elfin Forest) to correlate Bioassessment data with the mass loading stations. The Carlsbad WMA also contains four important coastal lagoons: Buena Vista Lagoon, Agua Hedionda Lagoon, Batiquitos Lagoon, and San Elijo Lagoon. Buena Vista Lagoon lies within the cities of Oceanside and Carlsbad. It consists of three major basins: 1) the outer basin, from the mouth to the Coast Highway; 2) the middle basin, from the Coast Highway to Interstate 5; and 3) the inner basin, east of Interstate 5. One site in each of these basins was sampled during the Ambient Bay and Lagoon Monitoring Program (Figure 2-16). The Lagoon encompasses an area of 223 acres of wetland habitat, most of which is classified as open water (Coastal Conservancy 2000). Buena Vista Creek is the primary source of fresh water to the Lagoon, but it also receives inflow of groundwater and irrigation water from the area upstream on Vista Creek (RWQCB 1994). Tidal influence to the Lagoon is limited by a narrow channel and weir at the mouth, just south of Saint Malo Beach in Oceanside. Saltwater influence is further restricted by the Coast Highway and Interstate 5 bridge crossings and by the railroad crossing in the lower basin of the Lagoon. Treated effluent was discharged to the Lagoon from 1956 to 1965 and a large portion of the Lagoon was filled for development beginning in 1960. Currently, urban development surrounds the Lagoon, including residential neighborhoods to the north and south, a shopping mall on the east end, and Highway 78 on the northeast corner. Approximately 7 acres of the Lagoon is listed as impaired on the 2002 303(d) list for bacterial indicators, nutrients, sedimentation, and siltation (Table 6-2). Agua Hedionda Lagoon is located within the City of Carlsbad off Carlsbad Boulevard (Highway 101). It consists of three basins: 1) the outer basin, from Carlsbad Boulevard to the railroad trestle; 2) the middle basin, from the railroad trestle to the Interstate 5 bridge; and the inner basin, from Interstate 5 southeast nearly to Cannon Road. The Inner basin is much larger than the middle and outer basins. All three Ambient Bay and Lagoon sampling sites were located within the Inner basin; one along the western Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-5 shore, approximately 500 feet from Interstate 5, and two near the basin’s center (Figure 6-1). There are approximately 330 acres in Agua Hedionda Lagoon that have been classified as wetland habitat, most of which (253 acres) is open water (Coastal Conservancy 2000). Agua Hedionda Creek is the primary source of fresh water to the Lagoon, but it also receives runoff from Buena Creek, urban runoff from the north shore via storm drains, and agricultural runoff along the south shore. The Lagoon also contains a mariculture facility, a youth camp, a private marina, and a public boat launch. Historically, Agua Hedionda Lagoon was a coastal slough that was open intermittently to the ocean. In the 1950s San Diego Gas and Electric (SDG&E) excavated the slough and constructed an inlet channel and a tidal basin to provide cooling water for the Encina Power Plant, located on the Lagoon’s outer and middle basins. The Lagoon is dredged routinely to keep it open to the ocean, but berms located at the railroad trestle and Interstate 5 bridge limit the reach of tidal action. Agua Hedionda Lagoon is on the SWRCB 2002 303(d) list of impaired water bodies for bacterial indicators and sedimentation/siltation (Table 6-2). Batiquitos Lagoon is located along the southern edge of the City of Carlsbad, just north of La Costa Avenue. Similar to Agua Hedionda Lagoon, Batiquitos Lagoon is composed of three basins: 1) an outer basin, from Carlsbad Boulevard to the railroad trestle; 2) a middle basin, from the railroad trestle to the Interstate 5 bridge, and 3) an inner basin, from Interstate 5 east to El Camino Real. All three of the Ambient Bay and Lagoon Monitoring sites were located in the far eastern end of the inner basin near the mouth of San Marcos Creek (Figure 6-1). The Lagoon encompasses more than 540 acres of wetland habitat (Coastal Conservancy 2000). Approximately 350 acres is characterized as open water. San Marcos Creek and Encinitas Creek are the main sources of fresh water to the Lagoon. It also receives runoff from smaller tributary streams to the north and south, storm water runoff, and groundwater seeps. Historically, irrigated orchards were prevalent around the Lagoon and secondary treated wastewater was discharged to the Lagoon from 1967 to 1974. Currently, a golf course and residential neighborhoods lie to the north of the Lagoon, El Camino Real and commercial developments lie to the east, and La Costa Avenue and primarily vacant land lies to the south. In 1983, Batiquitos Lagoon was designated a State Ecological Reserve by the California Department of Fish and Game. As with Agua Hedionda Lagoon, berms at the railroad trestle and Interstate 5 limit the reach of tidal action in Batiquitos Lagoon. The mouth is frequently closed due to accumulated sediment. Batiquitos Lagoon is not on the SWRCB 303(d) List of Impaired Water Bodies. San Elijo Lagoon lies at the mouth of Escondido Creek, between the cities of Encinitas and Solana Beach. It covers an area of 576 acres of wetland habitat, but only 150 acres are characterized as open water (Coastal Conservancy 2000). In contrast to the large areas of open water habitat found in Buena Vista, Agua Hedionda, and Batiquitos Lagoons, San Elijo Lagoon consists of a narrow, sinuous channel with numerous side channels and shallow sloughs. Most of the main channel is located between the narrow mouth at Cardiff State Beach and Interstate 5, but a small portion of the Lagoon (approximately 1,000 feet) extends east of Interstate 5. Two of the three Ambient Bay and Lagoon Monitoring sites in San Elijo lagoon were located west of Interstate 5 and one was located just east of it (Figure 6-1). The main source of fresh water to San Elijo Lagoon is Escondido Creek, which discharges at the Lagoon’s eastern end. The Lagoon is connected to the ocean via a narrow rip rap channel under Highway 101, which is open intermittently. The railroad trestle and Interstate 5 bridge further restrict tidal influence. Historically, the Lagoon received wastewater from the City of Escondido from 1940 through 1973. Currently, the Lagoon is surrounded by residential, commercial, and agricultural developments in the Cities of Encinitas and Solana Beach. San Elijo Lagoon County Park and Ecological Reserve cover a large portion of the southeast side of the Lagoon. The Lagoon is on the SWRCB 2002 303(d) List for bacterial indicators, eutrophic conditions, and sedimentation/siltation. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-6 6.2 Storm Water Monitoring Summary Two mass loading stations located on Agua Hedionda and Escondido Creeks characterized storm water runoff from this watershed management area. The Agua Hedionda station has been monitored since the 1998-99 season and has seven years of historical data (21 storms monitored). Only two other mass loadings stations, Tecolote Creek located in the Mission Bay Watershed Management Area and Chollas Creek in the San Diego Bay Watershed Management Area, have similar historical data sets. Escondido Creek has been monitored for four storm seasons (12 storms monitored). 6.2.1 2004/2005 Results Agua Hedionda For the 2004-2005 wet season events, monitoring took place on October 17, 2004 and February 11 and 18, 2005. The results are included with previous measurements dating back to 1998 in Table 6-3. Common previous exceedances in fecal coliform, total dissolved solids, total suspended solids, turbidity, and Diazinon continued to appear during this monitoring season. However, Diazinon exceeded the water quality objective only once this season. Similar to the 2003-2004 season, there were also exceedances for biological oxygen demand (BOD), chemical oxygen demand (COD), and total phosphorus. No metal concentrations exceeded the water quality objectives during 2004-2005. Toxicity to Hyalella was observed during the October 17, 2004 storm event from Agua Hedionda Creek (See Section 3.1.6.2 for details on toxicity testing). The NOEC for 96-hour survival was 25% of the test sample. No toxicity to Hyalella was observed in the other two storm events from Agua Hedionda Creek. No toxicity to Ceriodaphnia or Selenastrum was observed in any of the Agua Hedionda Creek samples collected. Escondido Creek The Escondido Creek mass loading station was monitored for the fourth consecutive year for a total of 12 storms since 2001. For the 2004-2005 wet season events, monitoring took place on October 17, 2004 and February 11 and 18, 2005. The results are included with previous measurements dating back to 2001 in Table 6-4. Common previous exceedances in fecal coliform, total dissolved solids, and turbidity continued to appear during this monitoring season. There was a single exceedance for un- ionized ammonia, TSS and turbidity concentrations during the February 18, 2005 storm event. No metal concentrations exceeded the water quality objectives. Samples from Escondido Creek did not cause toxicity to any of the three test species for any of the storm events monitored during 2004-05. Table 6-3. Analytes measured at the Agua Hedionda Creek mass loading station.11/8/98 1/31/99 3/15/99 1/25/00 2/20/00 3/5/00 10/27/00 1/8/01 2/23/01 2/17/02 3/8/02 3/17/02 11/8/02 2/11/03 2/25/03 11/12/03 1/19/03 2/18/04 10/17/04 02/11/05 02/18/05Electrical Conductivity umhos/cm 652 1560 2270 2160 1172 1194 2220 3180 645 1320 2000 1520 955 588 5481203 2610 647 1760 502 700Oil And Grease mg/L 15 USEPA Multi-Sector General Permit 0.67 <0.5 <0.5 3.24 3.54 2.28 <1 <1 1 2 <1 2 <1.00 1.54 <1.00<1 <1 <1 <1 <1 <10% 0.07pH pH Units 6.5-8.5 Basin Plan7.6 7.8 7.5 7.76 7.5 7.677.70 8.00 7.61 7.50 No Data 7.760% 0.00BacteriologicalEnterococci MPN/100 mL3,000 9,000 13,000 13,000 11,000 30,000 50,000 13,000 110,00011,000 5,000 3,000 280,000 7,000 50,000Fecal Coliform MPN/100 mL 400 Basin Plan1,6002401,600 1,600 1,600<2500 11,000 13,000 13,000 500 24,000 23,000 7,000 5,000 5,000 2,300 2,30030,000 5,000 50,00095% 24.78Total Coliform MPN/100 mL 241,900 8,130 197,000 1,600 1,600 300 13,000 50,000 23,000 23,000 1,700 24,000 80,000 50,000 50,00017,000 5,000 3,000 300,000 17,000 80,000Wet ChemistryAmmonia As Nitrogen mg/L 0.3 0.15 0.21 0.4 <0.1 0.11 0.84 0.6 0.3 <0.1 0.1 0.1 0.25 0.25 0.620.43 <0.1 0.3 0.82 0.23 0.18Un-ionized Ammonia as Nμg/L 25 (a) Basin Plan4.51 1.93 6.946.11 1.23 3.02 4.4 0.4 4.10% 0.06Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit 20 <3 5.25 6 2.98 6.6 2 8.9 5 8 2.1 7.6 4.32 20.4 5.645.33.52 1632.24.67 3.6410% 0.34Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit 34 <5 21 70 66 41 62 69 56 50 44 61 88 46 60260 12410627975 3914% 0.66Dissolved Organic Carbon mg/L11.0 9.75 11.919.6 8.28 32.9 28.9 7.3 7.2Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.57 0.12 0.1 0.12 0.22 <0.1 0.06 0.22 0.42 <0.05 0.08 0.16 0.13 0.20 0.140.53 0.88 0.16 1.1 0.44 0.510% 0.15Nitrate Nitrogen As N mg/L 10 Basin Plan 2.1 0.86 1.1 1.6 1.42 1.58 0.4 1.3 1.1 1.1 0.7 1.2 1.27 1.15 0.553.1 1.7 3.2 1.93 2.41 0.880% 0.15Nitrite Nitrogen As N mg/L 1 Basin Plan <0.05 <0.05 <0.05 0.057 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0.05 <0.050.06 <0.05 <0.05 <0.05 <0.05 0.090% 0.03Surfactants (MBAS) mg/L 0.5 Basin Plan 0.25 0.07 <0.05 0.33 0.21 0.08 <0.5* <0.5* <0.5* <0.5* <0.5* <0.5* <0.1 <0.1 <0.1<0.5 <0.5 <0.5 <0.5 <0.5 <0.50% 0.39Total Dissolved Solids mg/L 500 Basin Plan by watershed892 1611 1356335 3621300 12904871050 1250389851 641310951<20851852 75241662% 1.52Total Kjeldahl Nitrogen mg/L 0.44 2.8 0.85 4.02 2.11 2.45 3 4.06 1.5 2.3 2.6 1.8 0.9 2.411 7.6 3.5 14.1 1.3 3.6Total Organic Carbon mg/L20.3 13.8 5.2118.1 14.5 47.2 44.7 7.31 14.2Total Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.72 0.13 0.12 0.16 1.04 0.74 0.11 0.24 0.62 0.5 0.25 0.53 0.87 0.83 1.140.632.280.562.150.47 1.1210% 0.36Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit 35 5 65134 286<20131 44239152 335 508 380 674 842<20403962 246 85967% 3.10Turbidity NTU 20 Basin Plan 8 1422 52 586.466 3029.5 1655.1 264 184 290 295 135 27.7383 27.5 21471% 5.78PesticidesChlorpyrifosμg/L 0.02 CA Dept. of Fish & Game <0.5* <0.5* <0.5* <0.5* <0.05* <0.5* <0.05* <0.03* <0.03* <0.03*0.047<0.03* <0.03*<0.01 <0.010.121<0.01 <0.01 <0.0145% 3.92Diazinonμg/L 0.08 CA Dept. of Fish & Game <0.5*0.38<0.5* <0.5* <0.5*0.41<0.5*0.1 0.18 0.13 0.28 0.464 0.194 0.320 0.1650.0510.0680.2670.044 <0.0180% 2.69Malathionμg/L 0.43 CA Dept. of Fish & Game0.10 0.36 0.11<0.01 0.331 0.076 0.330 0.083 <0.010% 0.36HardnessTotal Hardness mg CaCO3/L 137 365 568 52.2 155 35.3 680 532 201 592 669 290 418 370 205680 576 403 422 387 225Total MetalsAntimony mg/L 0.006 Basin Plan <0.0015 <0.0015 <0.0015 <0.0015 <0.0015 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 0.003 0.003<0.005 <0.006 <0.006 <0.005 <0.005 <0.0050% 0.26Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan <0.001 <0.001 <0.001 0.018 0.007 0.005 0.005 0.007 0.004 0.004 0.003 0.008 0.005 0.0100.015 0.008 0.008 0.008 0.007 <0.0020% 0.12Cadmium mg/L (b) 40 CFR 131 <0.00025 <0.00025 <0.00025 0.001 0.00025 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.0010.002 <0.001 <0.001 0.002 <0.001 <0.0010% 0.04Chromium mg/L (b) CTR (Cr VI) <0.005 0.12 <0.005 <0.005 <0.005 <0.005 <0.005 0.0150.042<0.005 <0.005 0.006 0.0090.017 0.021 <0.005 0.009 <0.005 <0.005 <0.0050% 0.00Copper mg/L (b) 40 CFR 131 <0.005 <0.005 <0.0050.054 0.020<0.005 0.0100.0310.006 0.010 0.0080.021 0.020.0420.055 0.02 0.031 0.032 0.012 0.01820% 0.69Lead mg/L (b) 40 CFR 131 <0.001 0.0017 <0.001 <0.001 <0.005 <0.002 0.002 0.010 <0.002 <0.002 0.003 0.008 0.006 0.0080.012 0.002 0.007 0.007 0.004 0.006Nickel mg/L (b)/0.1 40 CFR 131/ Basin Plan <0.005 0.010 <0.005 0.050 <0.005 0.007 0.007 0.010 0.007 0.006 0.003 0.009 0.007 0.0140.026 0.006 0.008 0.028 0.007 0.0070% 0.01Selenium mg/L 0.02 40 CFR 131 <0.001 <0.001 <0.001 0.002 <0.001 0.002 0.003 <0.002 0.006 <0.002 <0.002 <0.004 <0.004 <0.004<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.05Zinc mg/L (b) 40 CFR 1310.1940.035 0.010 0.110 0.050 <0.020 0.030 0.070 <0.020 0.027 <0.020 0.047 0.053 0.0890.148 0.036 0.083 0.270 0.042 0.0605% 0.26Dissolved MetalsAntimony mg/L (e) 40 CFR 131 <0.0015 <0.0015 <0.0015 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 0.002 0.002<0.005 <0.006 <0.006 <0.005 <0.005 <0.005Arsenic mg/L 0.34 (c) 40 CFR 131 <0.001 0.011 <0.001 0.005 0.003 0.003 <0.001 0.002 0.002 0.004 0.003 0.0030.002 0.002 0.003 <0.002 <0.002 <0.0020% 0.00Cadmium mg/L (b) 40 CFR 131 <0.00025 <0.00025 <0.00025 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.02Chromium mg/L (b) 40 CFR 131 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.00Copper mg/L (b) 40 CFR 131 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 0.006 <0.005 <0.005 0.041 0.010<0.005 0.008 0.005 0.006 0.005 <0.0050% 0.18Lead mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002<0.002 <0.002 <0.002 <0.002 <0.002 <0.0020% 0.01Nickel mg/L (b) 40 CFR 131 <0.005 <0.005 <0.005 0.007 0.005 0.002 0.004 0.005 <0.002 0.005 0.003 0.0020.004 0.002 0.002 0.007 0.003 0.0020% 0.00Selenium mg/L 0.02 (d) 40 CFR 131 <0.001 <0.001 <0.001 <0.002 0.002 <0.002 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004<0.005 <0.02 <0.005 <0.005 <0.005 <0.0050% 0.02Zinc mg/L (b) 40 CFR 131 0.01 <0.001 0.005 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 <0.020 0.291 0.030<0.02 <0.02 <0.02 <0.02 <0.02 <0.020% 0.09ANALYTE UNITS WQO SOURCEFrequency Above WQOMean Ratio to WQO2002-03General / Physical / Organic2000-01 2001-021998-99 1999-002004-052003-04 Table 6-3. Analytes measured at the Agua Hedionda Creek mass loading station.11/8/98 1/31/99 3/15/99 1/25/00 2/20/00 3/5/00 10/27/00 1/8/01 2/23/01 2/17/02 3/8/02 3/17/02 11/8/02 2/11/03 2/25/03 11/12/03 1/19/03 2/18/04 10/17/04 02/11/05 02/18/05ANALYTE UNITS WQO SOURCEFrequency Above WQOMean Ratio to WQO2002-032000-01 2001-021998-99 1999-002004-052003-04ToxicityCeriodaphnia 96-hr LC50 (%) 100>100 >100 >10081.25>100 >100 >100 >100 >100 >100 >100 >100 8% 0.10Ceriodaphnia 7-day survival NOEC (%) 100100 100 10050 50 50100 100 100 100 100 100 25% 0.50Ceriodaphnia 7-day reproduction NOEC (%) 100100 100 1005010050100 100 100 100 100 100 17% 0.33Hyalella 96-hr NOEC (%) 10010025100 10050 50100 10050 25100 100 42% 1.17Selenastrum 96-hr NOEC (%) 100100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Sources(e) USEPA has not published an aquatic life criterion value.(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.USEPA Federal Register Document 40 CFR Part 131, May 18, 2000.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Table 3 - Parameter benchmark values.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994.Shaded text – exceeds water quality objective.* Indicates detection limit exceeds water quality objective.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.Blank spaces have been verified and no data is available due to changes in the monitoring program. Table 6-4. Analytes measured at the Escondido Creek mass loading station.11/29/01 2/17/02 3/8/02 11/8/02 2/11/03 2/25/03 11/12/03 2/3/04 3/2/04 10/17/04 02/11/05 02/18/05Electrical Conductivityumhos/cm 1810 2540 1620 1826 1192 16751736 1452 1595 2860 2530 1390Oil And Grease mg/L 15 USEPA Multi-Sector General <1 <1 1 <1.00 1.16 <1.00<1 <1 <1 <1 <1 <10% 0.04pHpH Units 6.5-8.5 Basin Plan 7.7 7.7 7.7 7.55 7.46 7.417.78 8.02 7.83 7.91 8.16 8.100% 0.00Enterococci MPN/100 mL 8,000 1,400 17,000 50,000 80,000 80,00022,000 170,000 80,000 8,000 1,700 50,000Fecal Coliform MPN/100 mL 400 Basin Plan3,000 8,000 1,700 13,000 23,000 22,000 17,000 23,000 17,0001,300 1,100 50,000100% 37.52Total Coliform MPN/100 mL 50,000 30,000 8,000 30,000 50,000 80,00070,000 30,000 80,000 17,000 13,000 230,000Ammonia As N mg/L 0.4 0.19 0.18 0.29 0.32 0.41<0.1 0.18 1.2 0.33 0.26 0.32Un-ionized Ammonia as Nμg/L 25 (a)Basin Plan 2.78 2.37 3.190.85 3.96 17.70 1.3 6.036.811% 0.33Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General 5.2 4.4 5.3 4.07 9.93 5.004.443.121.7 6.26 3.32 5.28% 0.33Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General <25 25 40 73 51 694512659 68 37 428% 0.45Dissolved Organic Carbon mg/L 4.1 11.1 9.8610.9 6.31 13.4 29 3.86 6.47Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General 0.29 <0.05 0.14 0.32 0.32 0.130.36 0.25 0.22 0.26 <0.05 <0.050% 0.10Nitrate As N mg/L 10 Basin Plan 2.6 3.2 2.2 2.32 0.95 2.251.72 1.66 3.8 2.71 7.2 6.320% 0.31Nitrite As N mg/L 1 Basin Plan <0.05 <0.05 <0.05 <0.05 0.08 <0.05<0.05 <0.05 <0.05 <0.05 <0.05 <0.050% 0.03Surfactants (MBAS)mg/L 0.5 Basin Plan <0.5 <0.5 <0.5 <0.1 <0.1 <0.1<0.5 <0.5 <0.5 <0.5 <0.5 <0.50% 0.40Total Dissolved Solids mg/L 500 Basin Plan by watershed1150 1460 1160 1360 681 717 1300 665 13101460 1410 965100% 2.27Total Kjeldahl Nitrogen mg/L 2.1 1.2 1.6 1.6 2.0 1.73.2 4.2 1.7 2 0.7 3Total Organic Carbon mg/L 14.5 14.0 8.0411.1 13.1 12.7 34 6.9 13.8Total Phosphorus mg/L 2 USEPA Multi-Sector General 1.75 0.8 0.29 0.49 0.62 0.720.46 0.52 0.3 0.28 0.26 0.620% 0.30Total Suspended Solids mg/L 100 USEPA Multi-Sector General 53 <20 60 54150 22175 <20 55 60 7226425% 0.90TurbidityNTU 20 Basin Plan31.34.3324.5 38.3 111 192 40.1 116 2615.4 13.411775% 3.04Chlorpyrifosμg/L 0.02 CA Dept. of Fish & Game <0.03* <0.03* <0.03* <0.03* <0.03*0.030<0.01 <0.01 <0.01 <0.01 <0.01 <0.018% 0.56Diazinonμg/L 0.08 CA Dept. of Fish & Game0.94 0.27 0.27 0.122 0.1630.0630.061 0.067 0.037 <0.01 <0.01 <0.0142% 2.09Malathionμg/L 0.43 CA Dept. of Fish & Game <0.10 <0.10 <0.100.205 0.037 0.047 <0.01 <0.01 <0.010% 0.12Total Hardness mg CaCO3/L 564 681 532 530 365 388610 284 547 700 663 514Antimonymg/L 0.006 Basin Plan <0.002 <0.002 <0.002 <0.002 0.003 0.004<0.005 <0.005 <0.005 0.005 <0.005 <0.0050% 0.40Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan <0.001 <0.001 0.002 0.003 0.003 0.0040.003 0.004 0.003 0.003 0.004 <0.0020% 0.05Cadmium mg/L(b)40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.02Chromium mg/L(b)CTR (Cr VI)0.006 <0.005 <0.005 <0.005 0.008 <0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.00Coppermg/L(b)40 CFR 131 <0.006 <0.005 0.009 0.009 0.015 0.0190.0090.0180.006 0.008 0.022 0.020% 0.20Lead mg/L(b)40 CFR 131 <0.002 <0.002 <0.002 0.005 0.005 0.0050.002 0.006 <0.002 <0.002 0.002 0.005Nickel mg/L(b)/0.1 40 CFR 131/ Basin Plan 0.002 0.002 0.004 0.004 0.004 0.0060.004 0.003 <0.002 0.004 0.002 0.0030% 0.00Selenium mg/L 0.02 40 CFR 131 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.10Zinc mg/L(b)40 CFR 131 <0.020 <0.020 0.028 0.022 0.046 0.0660.033 0.065 <0.02 0.020 0.022 0.0520% 0.08Antimonymg/L(e)40 CFR 131 <0.002 <0.002 <0.002 <0.002 0.002 0.002<0.005 <0.005 <0.005 <0.005 <0.005 <0.005Arsenic mg/L 0.34 (c)40 CFR 131 <0.001 <0.001 0.002 0.002 0.002 0.002<0.002 0.002 <0.002 <0.002 <0.002 <0.0020% 0.00Cadmium mg/L(b)40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.02Chromium mg/L(b)40 CFR 131 0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.00Coppermg/L(b)40 CFR 131 <0.005 0.012 0.005 <0.005 0.049 0.008<0.005 0.005 <0.005 <0.005 0.007 <0.0058% 0.16Lead mg/L(b)40 CFR 131 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002<0.002 <0.002 <0.002 <0.002 <0.002 <0.002Nickel mg/L(b)40 CFR 131 0.002 0.005 0.002 0.003 0.002 <0.0020.002 0.002 0.002 0.003 0.002 <0.0020% 0.00Selenium mg/L 0.02 (d)40 CFR 131 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.10Zinc mg/L(b)40 CFR 131 <0.020 <0.020 <0.020 <0.020 0.230 0.022<0.02 <0.02 <0.02 <0.02 <0.02 <0.020% 0.082003-042001-02Dissolved Metals2002-03ANALYTE UNITS WQO SOURCEHardnessBacteriologicalFrequency Above WQOMean Ratio to 2004-05Total MetalsWet ChemistryPesticidesGeneral / Physical / Organic Table 6-4. Analytes measured at the Escondido Creek mass loading station.11/29/01 2/17/02 3/8/02 11/8/02 2/11/03 2/25/03 11/12/03 2/3/04 3/2/04 10/17/04 02/11/05 02/18/052003-042001-02 2002-03ANALYTE UNITS WQO SOURCEFrequency Above WQOMean Ratio to 2004-05ToxicityCeriodaphnia 96-hrLC50 (%)10035.36>100 >100 >100 >100 >100 >100 >100 > 100>100 >100 >1008% 0.24Ceriodaphnia 7-day survival NOEC (%)10025 50100 100 100 100 100 100 100100 100 10017% 0.50Ceriodaphnia 7-day NOEC (%)10025100 100 100 100 100 100 100 100100 100 1008% 0.33Hyalella 96-hr NOEC (%)100 100 100 100 100 100 100 100 100 100100 100 1000% 0.00Selenastrum 96-hr NOEC (%)100 100 100 100 100 100 100 100 100 100100 100 1000% 0.00SourcesBlank spaces have been verified and no data is available due to changes in the monitoring program.USEPA Federal Register Document 40 CFR Part 131, May 18, 2000.USEPA National Pollutant Discharge EliminationSystem(NPDES)Storm Water Multi-SectorGeneral Permit for Industrial Activities, 65 Federal Register(FR)64746, Final Reissuance,October 30, 2000. Table 3 - Parameter benchmark values.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.Shaded text – exceeds water quality objective.* Indicates detection limit exceeds water quality objective.(e) USEPA has not published an aquatic life criterion value.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-11 6.2.2 Relationships/Analyses Agua Hedionda Fecal coliform exceeded REC-1 water quality standards of 400 MPN/100 mL in 19 out of 21 storm events (90% of the storms) monitored since 1998-99. Total dissolved solids with a water quality objective of 500 mg/L for this WMA were exceeded in 13 out of the 20 storms monitored (65% of the time). Turbidity levels exceeded water quality objectives in 15 (75%) storms and total suspended solid concentrations exceeded WQOs during 14 (70%) storms. Prior years testing for Diazinon had a detection limit above the water quality objective, but since 2001-02 this parameter has been analyzed using a lower detection limit. Diazinon exceeded the water quality objective set by CA Department of Fish and Game in nine out of the last 13 storms, or 69% of the time tested since the new detection limits have been in place. Malathion data, available for the first time in 2002-03, continued to be below the objective. Total copper was the only metal with a somewhat recent exceedance above the water quality objective with one exceedance during 2002-2003 storm events. Together with the 3 previous exceedances, total copper has been above the water quality objective in 4 out of 20 storm events monitored (20% of the time). A statistical look at the past seven years of data has begun to reveal trends. Total suspended solids (R2=0.44), turbidity (R2=0.44), fecal coliform (R2=0.29), COD (R2=0.34), total phosphorus (R2=0.30), dissolved phosphorus (R2=0.25), total lead (R2=0.26), and total Kjeldahl nitrogen (R2=0.23) concentrations have significantly increased while electrical conductivity (R2=0.31) has significantly decreased. Toxicity testing has been performed on storm water for the past 4 years or 12 events (See Section 3.1.6.2 for details on toxicity testing). Storm water from Agua Hedionda Creek was toxic to Ceriodaphnia (96-hour test) during 1 out of 12 (8%) storm events; to Ceriodaphnia in the chronic survival test during 3 storms (25%); Ceriodaphnia in the chronic reproduction test during 2 storm events (17%); and to Hyalella (96-hour test) during 5 storm events (42%). Toxicity results from the 2004-2005 season were generally similar to toxicity results from the 2003-2004 season with only one Hyalella (96-hour) test showing toxicity during both storm seasons. No significant relationships between toxicity endpoints and COC were found. In order to illustrate the magnitude of the water quality exceedances for 2004-2005, the ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern. The results are shown in Figure 6-2. The largest single exceedances were for fecal coliform, which exceeded the WQO by 125 times during the February 18, 2005 storm event, by 75 times during the October 17, 2004 storm event and by 12 times during the February 11, 2005 storm. There were also large single exceedances for turbidity (19 times the WQO), TSS (9.5 and 8.5 times the WQO) and Diazinon (3.5 times the WQO). The average magnitude of water quality exceedances was also determined for each constituent by calculating the mean ratio of water quality results to the WQOs from all storm events from October 2001 through April 2004. Mean ratios are illustrated in Figure 6-2. The largest average exceedance for the period of record was for fecal coliform, which exceeded the WQO by nearly 25 times. The second largest average exceedance was for turbidity, which exceeded the WQO by approximately 5 times. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-12 TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 80 160 Ratio to WQOMean Ratio (Oct 01 to Apr 04) 10/17/04 2/11/05 2/18/05 Above WQO Figure 6-2. Agua Hedionda Creek water quality ratios. Samples collected during the 2004 dry weather monitoring program that had exceedances of the dry weather action levels located upstream of the MLS are shown in Table 6-5 (See Section 3.4 for details on dry weather sampling). Exceedances were noted for pH, conductivity, ammonia, total coliform, fecal coliform, and enterococcus. The only constituent that exceeded objectives during the 2004-2005 storm season and the 2004 dry weather program was fecal coliform. Fecal coliform exceeded the DWS action levels on two occasions and exceeded water quality objectives at the MLS during all three storms in 2004-2005. No other contaminant demonstrated a link of exceedances in both the dry and wet weather programs. Table 6-5. Agua Hedionda 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* St. Dev. Ratio of Exceedance pH 2 11 0.17 0.41 Conductivity 1 11 0.60 0.34 Ammonia 5 11 1.22 1.89 Total Coliform 3 12 1.02 1.76 Fecal Coliform 2 12 0.47 1.86 Enterococcus 2 12 1.25 4.64 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-13 A map for the watershed showing dry weather exceedances is found in Figure 6-3. Pie symbols appear at dry weather stations that have had water quality exceedances. The colored slices of the pie show the different constituent groups that contributed to the exceedances. Escondido Creek Fecal coliform exceeded REC-1 water quality standards of 400 MPN/100 mL in 12 out of 12 storm events (100% of the storms monitored). Total dissolved solids with a water quality objective of 500 mg/L were exceeded in 12 out of 12 storms (100%). These two constituents of concern are not incorporated into the Triad Decision Matrix, but are noted because they have persistently exceeded water quality objectives in both MLS in the watershed. Total suspended solid concentrations exceeded the WQO in three (25%) storms monitored and the turbidity WQO was exceeded in nine storms (75%). Diazinon exceeded the water quality objective set by CA Department of Fish and Game in 5 out of 12 storms or 42% of the time tested. However, there were no exceedances of Diazinon during the 2004-2005 storm season and further analysis of the data shows a significant decreasing trend (R2=0.47) in Diazinon concentrations. Malathion data, available for the first time in 2002-03, continued to be below the water quality objective. During the February 18, 2005 storm event, the water quality objective for un-ionized ammonia was exceeded for the first time since monitoring began during the 2001-2002 season. Toxicity testing has been performed on storm water for the past four years or 12 storm events (See Section 3.1.6.2 for details on toxicity testing). In Escondido Creek, there was toxicity to Ceriodaphnia (96- hour test) during 1 out of 12 (8%) storm events; to Ceriodaphnia in the 7-day survival test during two storms in 2001-02 (17%); to Ceriodaphnia in the 7-day reproduction test during one storm event (8%) in 2001-02. No toxicity has been observed to Hyalella and Selenastrum (96-hour test). There was no evidence of persistent toxicity in Escondido Creek for 2004-05. No significant relationships were found between toxicity and COC for Escondido Creek. In order to illustrate the magnitude of the water quality exceedances for 2004-2005, the ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern. Figure 6-4 illustrates the magnitude of the water quality exceedances at Escondido Creek. The largest single exceedance was for fecal coliform, which exceeded the WQO by 125 times during the February 18, 2005 storm. There was also a large single exceedance for turbidity (5.8 times the WQO). The average magnitude of water quality exceedances was also determined for each constituent by calculating the mean ratio of water quality results to the WQOs from all storm events from October 2001 through April 2004. Mean ratios are illustrated in Figure 6-4. The largest average exceedance for the period of record was for fecal coliform, which exceeded the WQO by 35 times. There were also notable average exceedances for turbidity (3.2 times), Diazinon (2.4 times) and TDS (2.1 times). There were numerous dry weather stations (DWS) in Escondido Creek due to extensive monitoring conducted by the City of Escondido (42 total). Of these, 25 were located upstream of the MLS (See Section 3.4 for details on dry weather sampling). Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-14 Figure 6-3. Carlsbad WMA dry weather exceedance map. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-15 TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 80 160 Ratio to WQOMean Ratio (Oct 01 to Apr 04) 10/17/04 2/11/05 2/18/05 Above WQO Figure 6-4. Escondido Creek water quality ratios. The number of dry weather exceedances and the average ratio of exceedance for the 2004 dry weather monitoring program is shown in Table 6-6. Constituents that exceeded the dry weather action levels at stations upstream of the MLS included turbidity, nitrate, total and fecal coliform. Of these, turbidity and total coliform had average ratios of exceedance over 1.5. Turbidity and fecal coliform were common COC at the MLS and dry weather stations that had exceeded objectives or action levels. A map for the watershed showing dry weather exceedances is found in Figure 6-3. Pie symbols appear at dry weather stations that have had water quality exceedances. The colored slices of the pie show the different constituent groups that contributed to the exceedances. Table 6-6. Escondido Creek 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* St. Dev. Ratio of Exceedance Turbidity 10 25 2.09 7.81 Nitrate 3 23 1.08 0.62 Total Coliform 14 23 1.73 5.53 Fecal Coliform 1 23 0.15 0.58 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-16 6.2.3 Third Party Data Third party data was collected from 10 locations in 2002 within the Carlsbad watershed under the Surface Water Ambient Monitoring Program (SWAMP) and was provided by the San Diego Regional Water Quality Control Board. Sampling sites were located on Loma Alta Creek, Buena Vista Creek, Buena Creek, Agua Hedionda Creek, San Marcos Creek, Encinitas Creek, Cottonwood Creek and Escondido Creek. Grab samples were collected from each station during dry weather once in March, April, June and September, 2002 (40 total observations). Results are presented in Table H-1 in Appendix H. Data collected from Agua Hedionda Creek and Escondido Creek were compared to the mass loading station and dry weather data results to provide qualitative assessments with current wet and dry weather results. The remaining stations within the watershed were too spatially disconnected from the MLS to correlate the data with any of the wet and dry weather monitoring results, however, exceedances were noted. One station, 904CBAQH6, was located on Agua Hedionda Creek, upstream of the MLS. There were water quality objective exceedances for sulfate, manganese and toxicity. Sulfate exceeded objectives during all four sampling events and manganese exceeded objectives during three monitoring events. Toxicity at Agua Hedionda Creek was evident for Ceriodaphnia dubia reproduction and Selenastrum capricornutum growth during all four sampling events. Hyalella survival and growth were each affected during one sampling event. All other constituents were below their respective water quality objectives. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedances were for toxicity to Ceriodaphnia and Hyalella. Toxicity to Ceriodaphnia survival and reproduction have been observed in wet weather samples collected at the Agua Hedionda Creek MLS during 3 out of 12 storm events for survival and during 2 out of 12 storm events for reproduction. Toxicity to Hyalella at the MLS was observed during 5 out of 12 storm events. Two sampling locations were located on Escondido Creek: station 904CBESC5 was located upstream of the MLS while the second location, 904CBESC8, was located in the same vicinity as the MLS. There were water quality objective exceedances for pH, sulfate, manganese, Diazinon and toxicity at both stations. Sulfate concentrations exceeded objectives during all four sampling events at both stations; manganese exceeded objectives during all four events at the station near the MLS location, and during one event at the station upstream of the MLS; pH exceeded objectives during two events at the location upstream of the MLS and during one event at the station near the MLS, and Diazinon concentrations exceeded objectives in the April sampling event at each station. Toxicity at Escondido Creek was evident for Ceriodaphnia dubia survival and Hyalella survival and growth. Hyalella growth was affected in the April event at each station; Hyalella survival was affected during one event at the station near the MLS and Ceriodaphnia survival was affected during one event at the station upstream of the MLS. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedances were for Diazinon and Ceriodaphnia survival and reproduction. Diazinon exceedances have been observed in wet weather samples collected at the Escondido Creek MLS in 5 out of 12 storm events. Even though Diazinon concentrations have historically exceeded water quality objectives, there were no exceedances during 2004-2005 and there appears to be a significant decreasing trend (R2=0.47) in concentrations. Toxicity to Ceriodaphnia survival has been observed during 2 out of 12 storm events, while Ceriodaphnia reproduction was affected only during 1 out of 12 storm events. Exceedances observed at the other seven stations within the Carlsbad watershed were similar to exceedances in Agua Hedionda Creek and Escondido Creek. Sulfate, manganese and toxicity consistently exceeded objectives at all sites. Out of 28 total observations, sulfate concentrations exceeded objectives Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-17 22 times; manganese concentrations exceeded objectives 19 times and toxicity to at least one test organism was evident during all but 2 sampling events. Other parameters, including pH, nitrate/nitrite as N and Diazinon exceeded objectives sporadically. Diazinon and pH exceeded objectives during 4 out of 28 observations and nitrate/nitrite as N exceeded objectives during all four sampling events at two stations (Buena Creek and Cottonwood Creek). Two other parameters, turbidity and selenium, only exceeded objectives during one event at one station (San Marcos Creek). 6.2.4 TIEs Agua Hedionda Creek has been identified as a TIE candidate site based upon chronic toxicity to Ceriodaphnia utilizing the Triad Decision Matrix. Since no toxicity was observed in Ceriodaphnia during the 2004-2005 storm season, TIE testing was not performed. The absence of observed toxicity in the Escondido Creek storm water samples excluded the need for TIE testing in 2004-2005. 6.2.5 Summary and Conclusions Both the Escondido Creek sub-watershed and the Agua Hedionda sub-watershed have similar water quality concerns. Bacteria, total dissolved solids, and total suspended solids have persistently exceeded WQOs. Diazinon has also persistently exceeded WQOs, but has shown signs of a decreasing trend. There appears to be a significantly increasing trend for total suspended solids, turbidity, fecal coliform, COD, total and dissolved phosphorus, total lead, and total Kjeldahl nitrogen concentrations in Agua Hedionda Creek. Third party data collected in 2002 indicated that sulfate, manganese and toxicity were detected above WQOs in various locations throughout. 6.3 Stream Bioassessment Stream bioassessment monitoring in the Carlsbad WMA included two sites on Agua Hedionda Creek and two sites on Escondido Creek. Agua Hedionda Creek was sampled at Melrose Drive and farther downstream at El Camino Real, adjacent to the mass loading station. Escondido Creek was sampled downstream of the Harmony Grove Bridge (just below the end of the channelized portion of the creek in the City of Escondido), and at a site in Elfin Forest. All four of these sites have been sampled every season since the start of the San Diego County bioassessment monitoring program in 2001. 6.3.1 Results and Discussion Melrose Drive Monitoring Site: AHC-MR The Aqua Hedionda Creek monitoring site at Melrose Drive had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Very Poor for both the October 2004 and May 2005 surveys (Table 6-7) (See Section 3.2 for details on the sampling approach). There were 23 different taxa collected in October, and 13 different taxa in May. There were no taxa collected that were highly intolerant to impairment, and the percent tolerant taxa was variable, comprising 54% and 3% of the community in October 2004 and May 2005, respectively. Percent collector filterers plus collector gatherers ranged from 51% to 98% of the community between October and May. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-18 Table 6-7. Selected Biological Metrics and Physical Measures of the Carlsbad WMA. Carlsbad Watershed Management Area Agua Hedionda Creek at Melrose Drive (AHC-MR) Agua Hedionda Creek at El Camino Real (AHC-ECR) Escondido Creek at Harmony Grove Bridge (ESC-HRB) Escondido Creek in Elfin Forest (ESC-EF) Survey Oct-04 May-05 Oct-04 May-05 Oct-04 May-05 Oct-04 May-05 Index of Biotic Integrity/ Qualitative Rating 13 Very Poor 5 Very Poor 10 Very Poor 12 Very Poor 10 Very Poor 8 Very Poor 15 Poor 12 Very Poor Metrics Taxa Richness 23 13 22 17 16 16 14 11 EPT Taxa (mayflies, stoneflies, and caddisflies) 2 2 3 3 2 3 5 5 % Intolerant Taxa 0% 0% 0% 0% 0% 0% 0.0% 0% % Tolerant Taxa 54% 3% 42% 5% 52% 10% 3% 1% Average Tolerance Value 7.2 5.3 6.6 5.2 6.5 5.6 5.3 5.6 % Collector Filterers +Collector Gatherers 51% 98% 82% 95% 86% 93% 92% 98% Physical Measures Elevation 360 40 630 360 Physical Habitat Score 108 136 84 81 113 79 182 161 Riffle Velocity (ft/sec) 0.8 2.6 1.9 1.6 1.5 0.8 3.6 1.6 Substrate Composition Silt 5% 27% 10% Sand 20% 8% 95% 80% 20% 90% 13% 20% Gravel 53% 65% 5% 20% 20% 7% 15% Cobble 12% 27% 18% 60% 12% Boulder 7% 10% 22% Bedrock/Solid 8% 10% 31% Water Quality Temperature ºC 17.9 18.0 15.8 25.0 18.2 29.7 17.6 21.2 pH 7.4 7.9 7.9 8.0 8.2 8.4 8.4 8.4 Specific Conductance (ms/cm) 2.297 1.733 2.341 2.622 1.868 1.891 1.938 1.920 Relative Chlorophyll (μg/L) 2.8 3.6 4.9 1.3 6.2 2.8 6.1 2.3 The in-stream habitat of the monitoring reach was sub-optimal. The substrate was dominated by unconsolidated gravel with some large tree-fall and roots providing stable habitat for invertebrate colonization. The riffles were quite shallow with moderate current velocity. Mature coast live oak provided good canopy cover throughout the monitoring reach. Water quality conditions were fair, with specific conductance values of 2.297 and 1.733 mS/cm, and pH values of 7.4 and 7.9 in October 2004 and May 2005, respectively. The benthic community was seasonally variable, with the amphipod, Hyalella, and the damselfly, Argia, dominating in October, and the mayfly, Baetis, and earthworms dominating in May (Table 6-8). Predator organisms comprised a much greater percentage of the benthic community in October. There were two different EPT taxa present in both surveys, represented by the Baetid mayflies, Baetis and Fallceon quilleri. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-19 Table 6-8. Carlsbad WMA Community Summary. Taxon Common Name Percent Composition Tolerance Value Functional Feeding Group Hyalella amphipod 36% 8 Collector Gatherer Argia dancer damselfly 21% 7 Predator Prostoma tongue worm 8% 8 Predator Oligochaeta earthworm 6% 5 Collector Gatherer Oct-04 Chironomidae non-biting midges 5% 6 Collector Gatherer/Filterer Baetis minnow mayfly 40% 5 Collector Gatherer Oligochaeta earthworm 33% 5 Collector Gatherer Simulium black fly 11% 6 Collector Filterer Chironomidae non-biting midges 11% 6 Collector Gatherer/Filterer Agua Hedionda Creek at Melrose Drive (AHC-MR) May-05 Ostracoda seed shrimp 1% 8 Collector Gatherer Oligochaeta earthworm 33% 5 Collector Gatherer Corbicula fluminea clam 16% 10 Collector Filterer Hyalella amphipod 15% 8 Collector Gatherer Turbellaria flatworm 9% 4 Predator Oct-04 Chironomidae non-biting midges 8% 6 Collector Gatherer/Filterer Baetis minnow mayfly 40% 5 Collector Gatherer Oligochaeta earthworm 31% 5 Collector Gatherer Chironomidae non-biting midges 9% 6 Collector Gatherer/Filterer Fallceon quilleri minnow mayfly 6% 4 Collector Gatherer Agua Hedionsa Creek at El Camino Real (AHC-ECR) May-05 Ostracoda seed shrimp 4% 8 Collector Gatherer Oligochaeta earth worm 29% 5 Collector Gatherer Hyalella amphipod 26% 8 Collector Gatherer Ostracoda seed shrimp 24% 8 Collector Gatherer Turbellaria flatworm 9% 4 Predator Oct-04 Chironomidae non-biting midges 6% 6 Collector Gatherer/Filterer Oligochaeta earth worm 48% 5 Collector Gatherer Chironomidae non-biting midges 30% 6 Collector Gatherer/Filterer Ostracoda seed shrimp 6% 8 Collector Gatherer Hydroptila microcaddisfly 3% 6 Piercer Herbivore Escondido Creek at Harmony Grove Bridge (ESC-HRB) May-05 Simulium black fly 3% 6 Collector Filterer Simulium black fly 30% 6 Collector Filterer Cheumatopsyche net-spinning caddisfly 24% 5 Collector Filterer Hydropsyche net-spinning caddisfly 17% 4 Collector Filterer Chironomidae non-biting midges 9% 6 Collector Gatherer/Filterer Oct-04 Baetis minnow mayfly 7% 5 Collector Gatherer Simulium black fly 57% 6 Collector Filterer Baetis minnow mayfly 28% 5 Collector Gatherer Chironomidae non-biting midges 8% 6 Collector Gatherer/Filterer Cheumatopsyche net-spinning caddisfly 2% 5 Collector Filterer Escondido Creek in Elfin Forest (ESC-EF) May-05 Fallceon quilleri minnow mayfly 2% 4 Collector Gatherer Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-20 El Camino Real Monitoring Site: AHC-ECR The Agua Hedionda Creek monitoring site at El Camino Real had a benthic macroinvertebrate community with Index of Biotic Integrity ratings of Very Poor for both the October 2004 and May 2005 surveys (Table 6-7). Taxonomic richness of the benthic community was 22 in October 2004 and 17 in May 2005, with 3 different EPT taxa per survey. There were no organisms collected that are highly intolerant to impairment, and highly tolerant taxa comprised from 42% to 5% of the community during October 2004 and May 2005, respectively. The in-stream habitat of the monitoring reach was fair. The substrate was comprised almost entirely of actively eroding sand with silt deposits in the low current areas. Willow roots and woody debris provided some stable surfaces for macroinvertebrate colonization. The low gradient topography created only flat riffles (runs) with moderate current velocity. Water quality measures indicated an increase in total dissolved solids from the Melrose Drive site, with specific conductance values of 2.341 ms/cm in October 2004 and 2.622 ms/cm in May 2005. This increase was more pronounced in the May survey. Values for pH were 7.9 and 8.0 in the October and May surveys, respectively. The benthic community at the El Camino Real site was seasonally variable with an abundance of clams (Corbicula fluminea) in October, and with the mayfly, Baetis, dominating in May (Table 6-8). Oligochaetes were abundant in both surveys, likely due to substantial organic detritus in the substrate. The lack of clams in May might have been due to the heavy winter rains flushing the stream bed. Collector filterers and collector gatherers dominated both surveys, comprising 82% and 95% of the community in October and May, respectively. The Aqua Hedionda mass loading station was located adjacent to the bioassessment station at El Camino Real, and water quality measures may be correlated with the site. Constituents of concern identified during storm water sampling that would have a negative impact on the biological community included total dissolved solids, total suspended solids, turbidity, and the pesticides, Chlorpyrifos and Diazinon (Table 6-3). Total metals were below the WQOs in 2004-2005, but the measured levels of copper, lead, and zinc may have had a cumulative negative effect on more sensitive organisms. Toxicity to Hyalella from storm water was detected in the first storm of 2004, and this would indicate that the water quality may prevent the colonization of highly sensitive organisms (Hyalella has a tolerance value of 8). Harmony Grove Bridge Monitoring Site: ESC-HRB The Escondido Creek monitoring site at Harmony Grove Bridge had a benthic macroinvertebrate community with Index of Biotic Integrity ratings of Very Poor for both the October 2004 and May 2005 surveys (Table 6-7). Taxonomic richness of the benthic community was the same for both surveys, with 16 different taxa, and with two and three different EPT taxa per survey. There were no organisms collected that are highly intolerant to impairment, and highly tolerant taxa comprised from 52% to 10% of the community in October 2004 and May 2005, respectively. The physical habitat of the monitoring reach was sub-optimal to marginal. The in-stream habitat quality for the May survey was substantially lower than the October survey due to a large amount of fine sediment deposits in the riffles. The riparian zone has been disturbed somewhat, although a habitat restoration project has restored much of the vegetation in the monitoring reach. Specific conductance values were moderate, measuring1.868 ms/cm in October and 1.891 ms/cm in May (Table 6-7). Values for pH were 8.2 in October and 8.4 in May. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-21 The benthic community at the Harmony Grove Bridge site was dominated by Oligochaetes (earthworms) in both surveys (Table 6-8). The October survey also had high abundances of the amphipod, Hyalella, and Ostracods. Chironomid midges were abundant in the May survey. Elfin Forest Monitoring Site: ESC-EF The Escondido Creek monitoring site in Elfin Forest had a benthic macroinvertebrate community with Index of Biotic Integrity ratings of Poor and Very Poor for the October 2004 and May 2005 surveys, respectively (Table 6-7). Taxonomic richness of the benthic community was relatively low, with 14 and 11 different taxa. The number of EPT taxa was relatively high for an urban affected site, with five different EPT taxa per survey. There were no organisms collected that are highly intolerant to impairment, and highly tolerant taxa were present in very low numbers comprising from three to one percent of the community. The physical habitat of the site has been optimal in the past, with a complex and stable substrate dominated by cobble, and with good flow and current velocity. However, the heavy winter rains caused substantial erosion, with the amount of exposed cobble decreasing from an estimated 60% of the stream bed to 12% between October and May, with an increase in exposed boulder/bedrock and sand deposits (Table 6-7). The riparian zone was mostly natural with dense bank vegetation and a willow/oak canopy. The specific conductance was very similar to the upstream site at Harmony Grove Bridge: 1.938 ms/cm in October 2004 and 1.920 ms/cm in May 2005. Values for pH and chlorophyll were also very similar to the upstream site. Water temperature decreased between the two sites, likely due to the Harmony Grove Bridge site being situated downstream of a channelized portion of the stream, with the temperatures then cooling through the wooded areas of Elfin Forest. The benthic community was dominated by the black fly, Simulium, in both surveys (Table 6-8). Other constituents of the community reflected typical seasonal changes that have been observed at the site in the past, with Hydropsychid caddisfly abundance decreasing from 41% to 2% of the community between October 2004 and May 2005. Dense filamentous algae growths occur in the spring,, which then die off by the fall survey. Hydropsychid caddisflies colonize the surface of rocks, but the thick algae prohibits this in the spring. Baetis and Simulium were observed clinging to the algae in May, but in October, with the surface of the cobble exposed, Hydropsyche and Cheumatopsyche were able to colonize the substrate along with Simulium. The Escondido Creek mass loading station was located several miles downstream of the bioassessment station in Elfin Forest, and water quality measures from storm water may have contained constituents that were contributed below the bioassessment site. Constituents of concern identified during storm water sampling that would have a negative impact on the biological community included total dissolved solids, total suspended solids, and turbidity (Table 6-4). Pesticides were not detected in 2004-2005 and toxicity to Ceriodaphnia and Hyalella from storm water has not been an issue at the site for several years. It may be noted that the tolerance of Hyalella is higher than most benthic macroinvertebrates, and biological degradation may be quite substantial before Hyalella is impacted by water quality in natural systems. 6.3.2 Summary and Conclusions The Carlsbad WMA included four bioassessment monitoring sites, two on Agua Hedionda Creek and two on Escondido Creek. Index of Biotic Integrity scores rated the benthic communities Very Poor at all four sites, with the exception of Escondido Creek in Elfin Forest, which was rated Poor in the October 2004 Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-22 survey. A substantial amount of substrate alteration occurred between the October and May surveys in Escondido Creek. The Aqua Hedionda Creek sites both had marginal in-stream habitat conditions, which may have limited macroinvertebrate colonization. 6.4 Ambient Bay and Lagoon Monitoring Program There are four coastal embayments in the Carlsbad WMA that were monitored in the ABLM Program: Buena Vista Lagoon, Agua Hedionda Lagoon, Batiquitos Lagoon, and San Elijo Lagoon. 6.4.1 Results and Discussion Buena Vista Lagoon 6.4.1.1 Phase I Results and Discussion Sediment samples were collected in Buena Vista Lagoon for the ABLM Program on June 8, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 6-5. Overall, the sites sampled in Buena Vista Lagoon had the smallest median grain size (mean of 21.23 μm), the largest percentage of fines (mean of 82.74%), and the highest TOC content (mean of 5.19%) of any of the twelve coastal embayments assessed in Phase I (Table 6-9). The grain size distribution was similar among the nine sites sampled, with clay and silt as the major components at all but one site. Sediments at Site 1L-1, situated at the mouth of the Lagoon closest to the ocean, consisted primarily of sand (75.5%). TOC content was also similar among most sites and no obvious spatial patterns were apparent. As with the grain size distribution, TOC content at Site 1L-1 was different from other sites in the Lagoon, with a lower TOC content (2.43%). The sites that ranked highest for grain size and TOC and therefore selected for Phase II assessment, two were located in the outer stratum (1M-1 and 1R-1), and one was located in the inner stratum (3L-1) (Table 6-9). Figure 6-5. Map of Phase I site locations in Buena Vista Lagoon. Sites with yellow triangles were selected for Phase II assessment. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-23 Table 6-9. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Buena Vista Lagoon. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II BVL-1L-1 0.00 75.5 11.31 13.20 153 62 24.50 2.43 1 1 2 BVL-1M-1 0.68 5.5 19.4 74.4 1.68 NC 93.83 7.75 7 9 16 * Yes BVL-1R-1 0.14 6.11 19.6 74.1 1.69 NC 93.75 5.98 6 6 12 * Yes BVL-2L-1 0.03 2.77 25.7 71.5 1.71 NC 97.20 2.98 9 2 11 BVL-2M-1 0.03 6.72 25.6 67.7 1.81 NC 93.25 3.57 4 3 7 BVL-2R-1 0.00 37.65 23.2 39.2 12.50 6.35 62.35 6.40 2 7 9 BVL-3L-1 0.09 4.62 57.8 37.5 7.42 4.85 95.29 5.29 8 4 12 * Yes BVL-3M-1 0.01 6.57 43.4 50.0 3.90 3.84 93.42 5.60 5 5 10 BVL-3R-1 0.17 8.73 53.0 38.1 7.69 5.45 91.09 6.73 3 8 11 Mean of all sites 0.13 17.13 31.00 51.74 21.23 16.47 82.74 5.19 St. Dev. 0.22 24.34 16.30 21.49 49.54 25.45 24.27 1.81 NC = Not calculable (%silt + %clay > 84%) 6.4.1.2 Phase II Results and Discussion The three sites selected in the Buena Vista Lagoon as part of Phase I were sampled in Phase II on July 9, 2004. Sediments from Sites 1M-1, 1R-1 and 3L-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 6-10. Table 6-10. Summary of chemistry, toxicity, and benthic community structure in Buena Vista Lagoon. CHEMISTRY* TOXICITY* BENTHIC COMMUNITY Analyte ERL ERM Result ERM- Q Percent Survival Index 1M-1 1R-1 3L-1 Mean St. Dev. Total METALS (mg/kg) Abundance 77 52 36 55 20.7 165 Antimony NA NA <1.74 NA Richness 6 6 3 5 1.73 10 Arsenic 8.2 70 7.38 0.105 Diversity 1.01 0.71 0.25 0.66 0.38 NA Cadmium 1.2 9.6 0.646 0.067 Evenness 0.56 0.40 0.23 0.40 0.17 NA Chromium 81 370 35.9 0.097 Dominance 2 1 1 1.33 0.58 NA Copper 34 270 43.5 0.161 Lead 46.7 218 32.5 0.149 Nickel 20.9 51.6 14.1 0.273 Selenium NA NA <1.74 NA Zinc 150 410 180 0.439 Mean ERM-Q 0.185 98% Not Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-24 Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, seven metals common to all the embayments were detected above the detection limit in sediments from Buena Vista Lagoon: arsenic, cadmium, chromium, copper, lead, nickel, and zinc (Table 6-10). Concentrations of these metals were higher than at most other embayments assessed in the ABLM Program, but were low compared to the ERL and ERM values. These results are similar to the 2003 ABLM program with the exception of cadmium which was not detected. No concentrations exceeded the ERM values and only copper and zinc exceeded the ERL during 2004. During 2003 only copper exceeded the ERL. There were no PAHs, PCBs, or pesticides found above the detection limit in Buena Vista Lagoon. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was 0.185. This value exceeded the threshold of 0.10, which suggests that sediments in Buena Vista Lagoon have a greater probability of producing adverse biological effects than embayments with mean ERM-Qs below the threshold (Long et al. 1998). Although the threshold was exceeded it should be noted that the concentrations of all metals assessed were low in Buena Vista Lagoon, three to ten times lower than their respective ERMs. This is also similar to the 2003 results where the mean ERM quotient was 0.183. Toxicity. The percent survival of E. estuarius exposed to Buena Vista Lagoon sediments in a 10-day acute toxicity test was 98% (Table 6-10). Percent survival was not significantly different from that of the Control (99%). During the 2003 ABLM program toxicity was observed, but the source of toxicity was unknown. Benthic Community Structure. A total of 165 organisms were collected from Buena Vista Lagoon, representing 10 taxa (Table 6-10). During the 2003 ABLM program a total of 56 organisms were collected, representing 3 taxa. The benthic indices for 2004 were similar between Sites 1M-1 and 1R-1, where the majority of the organisms were found. Based on these indices, the benthic community structure at Buena Vista Lagoon had a rank of 9, where 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. This relative low ranking is due to the very low abundance and number of species, both of which were lower in Buena Vista Lagoon than any other embayment assessed. The low taxa abundance and diversity in Buena Vista Lagoon were likely related to water quality. Buena Vista Lagoon was the only embayment assessed that consisted primarily of freshwater. The mouth of the Lagoon is closed to the ocean and therefore receives no tidal exchange. The salinity was below 4.3 ms/cm at all three sites sampled during the Phase II assessment and large mouth bass, a freshwater game fish, were observed in the outer lagoon at the time of sampling. The freshwater nature of the Lagoon is also reflected in the benthic infaunal community. Of the species identified, the family Chironomidae (a group that includes the aquatic larval stages of freshwater flies and midges) was most abundant, accounting for over 74% of the organisms collected (Table 6-11). The freshwater crustacean Hyalella azteca (also known as a scud) was the next most abundant taxon consisting of 16.9% of the organisms collected. These results are similar to the 2003 results where Chironomidae accounted for 50% of the organisms collected followed by Hyalella azteca. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-25 Table 6-11. Dominant infaunal species found in Buena Vista Lagoon during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Chironomidae Minor Phyla 123 74.5 BVL Hyalella azteca Crustacean 28 16.9 Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Buena Vista Lagoon were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 6-6. For Buena Vista Lagoon, the relative ranks were nine for chemistry, one for toxicity, and nine for benthic community structure. It is important to remember that the conditions in Buena Vista Lagoon are very different from all the other embayments assessed in the ABLM Program. Because this Lagoon is closed to the ocean, it receives no tidal exchange, has no salt water influence, and functions more as a freshwater lake or wetland than a coastal estuary. The depositional nature of the Lagoon was reflected in the physical nature of the sediments, which contained a much greater percentage of fines and higher TOC content than any other embayment. This likely contributed to the relatively high mean ERM-Q value and presence of toxicity in this embayment. In addition, the freshwater nature of the Lagoon was reflected in the unique benthic community assemblage, which makes it difficult to compare directly with the other embayments assessed. Thus, the low rankings for Buena Vista Lagoon relative to the other embayments are most likely due to the Lagoon’s freshwater nature rather than any other factor. 6.4.1.3 Summary and Conclusions Sediments in Buena Vista Lagoon were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size): Sites 1R-1 and 1M-1 in the outer stratum, and 3L-1 in the inner stratum. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven of the nine metals analyzed were found in the Lagoon sediments. Concentrations were slightly higher than those found in other embayments, but were low compared to ERL and ERM values. Concentrations of all the metals were below their respective ERLs except copper and zinc, which were slightly higher than the ERL, but did not exceed the ERMs. The mean ERM-Q for Buena Vista Lagoon was the third highest among the embayments assessed in the ABLM Program. There were no PAHs, PCBs, or pesticides found above the 0 1 2 3 4 5 6 7 8 9 10 Chemistry Toxicity Benthos RankingFigure 6-6. Relative rankings for sediment in Buena Vista Lagoon Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-26 detection limit in Buena Vista Lagoon. The percent survival of test organisms exposed to the Lagoon sediments was not significantly different than that of a Control, which suggests the lack of toxic agents. However, the low concentrations of the constituents monitored suggest that they did not account for the elevated toxicity. Only 10 taxa were found in Buena Vista Lagoon, most of which were freshwater animals. The low relative rankings are likely due to the influence of fresh water and lack of tidal flushing in the Lagoon rather than a greater than average contaminant loading. Compared to the other embayments in the 2004 ABLM program, Buena Vista Lagoon had an overall rank of seven. During the 2003 ABLM program the Lagoon had an overall rank of twelve. A decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 6.4.2 Results and Discussion for Agua Hedionda Lagoon 6.4.2.1 Phase I Results and Discussion Sediment samples were collected in Agua Hedionda Lagoon on June 8, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 6-7. Sediment grain size was extremely variable in Agua Hedionda Lagoon. Among the nine stations sampled, median grain size ranged from 2.40 μm at Site 3L-1 in the inner Lagoon to 214.66 μm at Site 3M-1, also in the inner Lagoon (Table 6-12). However, strong spatial patterns were apparent among the three strata sampled. Sediments in the outer Lagoon consisted primarily of sand (88.8% to 96.7%) and had a lower TOC content (0.14% to 0.43%) than sites in the middle and outer Lagoon. Sediments at Sites 3L-1 and 3R-1 in the inner Lagoon were also distinctly different from those at other sites in the Lagoon. Sediments at these sites had a much smaller median grain size consisting primarily of clay, and a higher TOC content than the other sites in the Lagoon. Sites 3L-1 and 3R-1 ranked highest for Phase II assessment due to the high percentage of fine sediments and high TOC content found in this part of the Lagoon (Table 6-12). Site 2L-2 in the middle stratum was also selected for Phase II assessment. Figure 6-7. Map of Phase I site locations in Agua Hedionda Lagoon. Sites with yellow triangles were selected for Phase II assessment. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-27 Table 6-12. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Agua Hedionda Lagoon. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II AHL-1L-1 0.19 96.7 1.10 1.99 137 163 3.09 0.43 1 4 5 AHL-1M-1 0.07 88.8 7.78 3.32 94 94 11.10 0.23 3 2 5 AHL-1R-1 0.06 94.6 2.83 2.53 137 136 5.36 0.14 2 1 3 AHL-2L-2 0.73 11.9 46.13 41.24 8.9 NC 87.37 1.39 8 8 16 * Yes AHL-2M-2 0.35 61.0 27.56 11.04 73.7 38.45 38.60 0.67 6 6 12 AHL-2R-1 0.12 76.0 11.85 12.00 112.6 54.4 23.85 0.45 5 5 10 AHL-3L-1 0.11 5.11 39.22 55.56 2.40 NC 94.78 1.50 9 9 18 * Yes AHL-3M-1 0.25 87.66 4.60 7.49 214.66 187.73 12.08 0.38 4 3 7 AHL-3R-1 0.0 16.1 32.22 51.70 3 NC 83.92 1.12 7 7 14 * Yes Mean of all Sites 0.21 59.77 19.26 20.76 87.05 112.16 40.02 0.70 St. Dev. 0.22 38.16 17.17 22.15 72.88 59.94 38.10 0.51 NC = Not calculable (%silt + %clay > 84%) 6.4.2.2 Phase II Results and Discussion The three sites selected in the Agua Hedionda Lagoon as part of Phase I were sampled in Phase II on July 16, 2004. Sediments from Sites 2L-2, 3L-1 and 3R-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 6-13. Table 6-13. Summary of chemistry, toxicity, and benthic community structure in Agua Hedionda Lagoon. CHEMISTRY* TOXICITY* BENTHIC COMMUNITY Analyte ERL ERM Result ERM- Q Percent Survival Index 2L-2 3L-1 3R-1 Mean St. Dev. Total METALS (mg/kg) Abundance 622 438 25 361 306 1085 Antimony NA NA <1.74 NA Richness 45 16 7 22.6 19.9 54 Arsenic 8.2 70 8.28 0.118 Diversity 2.74 0.68 1.36 1.59 1.05 NA Cadmium 1.2 9.6 <0.174 NA Evenness 0.72 0.24 0.70 0.55 0.27 NA Chromium 81 370 33.2 0.090 Dominance 9 1 2 4 4.36 NA Copper 34 270 23.1 0.086 Lead 46.7 218 13.7 0.063 Nickel 20.9 51.6 10.6 0.205 Selenium NA NA <1.74 NA Zinc 150 410 70.2 0.171 Mean ERM-Q 0.122 85% Not Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-28 Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these six metals were detected above the detection limit in sediments from the Agua Hedionda Lagoon: arsenic, chromium, copper, lead, nickel, and zinc (Table 6-13). All concentrations were low compared to ERL and ERM values and only arsenic slightly exceeded the ERL. These results are similar to the 2003 ABLM program where the same six metals were detected, however both arsenic and copper slightly exceeded their respective ERLs in 2003. There were no PAHs, PCBs, or pesticides found above the detection limit in Agua Hedionda Lagoon. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was 0.122. This value exceeded the threshold of 0.10, which suggests that sediments in Agua Hedionda Lagoon have a greater probability of producing adverse biological effects than embayments with mean ERM-Qs below the threshold (Long et al. 1998). Although the threshed was exceeded, it is important to remember that the concentrations of all metals were low in Agua Hedionda Lagoon, at least three times less than their respective ERMs. This is also similar to the 2003 results where the mean ERM quotient was 0.168. Toxicity. The percent survival of E. estuarius exposed to Agua Hedionda Lagoon sediments in a 10-day acute toxicity test was 85% (Table 6-13). Percent survival was not significantly different from that of the Control (99%), suggesting that Agua Hedionda Lagoon sediments were not toxic to the test organisms. During the 2003 ABLM program toxicity was observed, but the source of toxicity was unknown. Benthic Community Structure. A total of 1085 organisms were collected from Agua Hedionda Lagoon, representing 54 taxa (Table 6-13). During the 2003 ABLM program a total of 510 organisms were collected, representing 33 taxa. Site 2L-2 had greater taxa abundance, richness, diversity, evenness and dominance than the other sites in the Lagoon during 2004. Based on these indices, the benthic community structure in Agua Hedionda Lagoon had a rank of 6 compared to the other embayments where a rank of 1 represents the healthiest community with the lowest combined index score and 12 represents the least-healthy community. Similar to the 2003 ABLM program, one species dominated the infaunal community in Agua Hedionda Lagoon during 2004. The sea slug, Acteocina inculta, accounted for 37.2% (55.5% in 2003) of the taxa collected (Table 6-14). This mollusk was the fourth most abundant species among all the embayments assessed. The second most abundant taxon in Agua Hedionda Lagoon was the isopod, Paracerceis sculpta, accounting for 15.6% of the animals collected. The polychaete worm, Exogone lourei, was the third most abundant taxon found (8.3% of the taxa collected). Table 6-14. Dominant infaunal species found in the Agua Hedionda Lagoon during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Acteocina inculta Mollusca 404 37.2 Paracerceis sculpta Crustacea 169 15.6 AHL Exogone lourei Polychaeta 90 8.3 Values were calculated from the total of all sites assessed Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-29 Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Agua Hedionda Lagoon were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 6-8. For Agua Hedionda Lagoon, the relative ranks were five for chemistry, seven for toxicity, and six for benthic community structure. 6.4.2.3 Summary and Conclusions Sediments in Agua Hedionda Lagoon were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size): Site 2L-2 in the middle stratum, and 3R-1 and 3L-1 in the inner stratum. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that six metals found in all the embayments assessed were also found in Agua Hedionda Lagoon at concentrations above the detection limit. Concentrations were slightly higher than those found in other embayments, but only arsenic exceeded the respective ERL. The mean ERM-Q for Agua Hedionda Lagoon exceeded the threshold value of 0.10 but concentrations of all metals were low, at least three times less than their respective ERMs. There were no PAHs, PCBs, or pesticides found above the detection limit in Agua Hedionda Lagoon. Toxicity associated with the sediments was not significantly different from that of the Control, suggesting that toxic constituents were not present in the Lagoon. Benthic community indices suggested that the biotic community in the Lagoon sediments was fair compared to other embayments in San Diego County. The infaunal community was dominated by the sea slug, Acteocina inculta, which accounted for 37.2% of the taxa collected. The relative ranks for Agua Hedionda Lagoon compared to the other embayments in the ABLM Program were five for chemistry, seven for toxicity, and six for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Agua Hedionda Lagoon had an overall rank of six. During the 2003 ABLM program the Lagoon had an overall rank of nine. A decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 0 1 2 3 4 5 6 7 8 Chemistry Toxicity Benthos RankingFigure 6-8. Relative rankings for sediment in Agua Hedionda Lagoon. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-30 6.4.3 Results and Discussion for Batiquitos Lagoon 6.4.3.1 Phase I Results and Discussion Sediment samples were collected in Batiquitos Lagoon for the ABLM Program on June 7, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 6-9. Strong spatial patterns were apparent among the three strata sampled in Batiquitos Lagoon. All three sites in the outer Lagoon and two of the three sites in the middle Lagoon (2L-1 and 2M-1) contained sediments that consisted primarily of sand (Table 6-15). Sand was particularly prevalent in sediments closest to the mouth of the Lagoon (1M-1 and 1L-1), nearest the ocean. In contrast, sediments at sites in the inner Lagoon consisted primarily of clay and silt. All three sites in the inner Lagoon contained close to 96% fine-grained sediments. The TOC content in Batiquitos Lagoon followed a similar pattern to that of grain size. Sediments at sites in the inner Lagoon had higher TOC levels than most of the sites in the middle and outer Lagoon. One exception to this pattern was Site 2R-1 in the middle stratum, which had the highest TOC content of any of the nine sites sampled (1.91%). Two Sites in the inner stratum and Site 2R-1 in the middle stratum were selected for Phase II assessment, primarily due to the high percentage of fine grained sediments found in this area of the Lagoon (Table 6-15). Site 3R-1 also ranked high because of the high TOC content in sediments at this site. However, it was not selected for Phase II assessment because the percentage of fine grained sediments at this site was lower than that found at Site 3M-1, which had the same rank sum as Site 3R-1. Figure 6-9. Map of Phase I site locations in Batiquitos Lagoon. Sites with yellow triangles were selected for Phase II assessment. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-31 Table 6-15. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Batiquitos Lagoon. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II BL-1L-1 3.06 80.4 9.1 7.4 106.9 107.27 16.57 0.57 1 2 3 BL-1M-1 0.67 76.4 8.95 14.01 112 39 22.96 0.55 2 1 3 BL-1R-1 0.53 69.9 13.22 16.31 107 25 29.53 0.79 4 3 7 BL-2L-1 0.17 49.9 16.2 33.7 62.6 NC 49.90 0.80 5 4 9 BL-2M-1 1.96 73.2 6.7 18.1 95.68 16.86 24.84 0.99 3 5 8 BL-2R-1 0.00 2.9 33.7 63.3 1.8 NC 97.05 1.91 8 9 17 * Yes BL-3L-1 0.00 0.88 41.4 57.7 1.94 NC 99.12 1.32 9 6 15 * Yes BL-3M-1 0.00 7.46 37.1 55.5 1.93 NC 92.54 1.46 7 7 14 * Yes BL-3R-1 0.10 7.97 32.5 59.4 1.85 NC 91.92 1.60 6 8 14 * Mean of all Sites 0.72 41.01 22.11 36.17 54.64 46.98 58.27 1.11 St. Dev. 1.08 35.42 13.84 22.80 52.02 41.19 36.19 0.48 NC = Not calculable (%silt + %clay > 84%) 6.4.3.2 Phase II Results and Discussion The three sites selected in the Batiquitos Lagoon as part of Phase I were sampled in Phase II on July 12, 2004. Sediments from Sites 2R-1, 3L-1 and 3M-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 6-16. Table 6-16. Summary of chemistry, toxicity, and benthic community structure in Batiquitos Lagoon. CHEMISTRY* TOXICITY*BENTHIC COMMUNITY Analyte ERL ERM Result ERM-Q Percent Survival Index 2R-1 3L-1 3M-1 Mean St. Dev. Total METALS (mg/kg) Abundance 1897 839 128 955 890 2864 Antimony NA NA <1.74 NA Richness 44 19 10 24.3 17.6 53 Arsenic 8.2 70 9.19 0.131 Diversity 1.36 1.50 1.36 1.41 0.08 NA Cadmium 1.2 9.6 <0.174 NA Evenness 0.36 0.51 0.59 0.48 0.12 NA Chromium 81 370 30.4 0.082 Dominance 2 2 2 2 0.00 NA Copper 34 270 18.6 0.069 Lead 46.7 218 15.7 0.072 Nickel 20.9 51.6 10.6 0.205 Selenium NA NA <1.74 NA Zinc 150 410 76.2 0.186 Mean ERM- Q 0.124 67 % Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-32 Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, six metals were detected above the detection limit in sediments from Batiquitos Lagoon: arsenic, chromium, copper, lead, nickel, and zinc (Table 6-16). These metals were common to all the coastal embayments monitored in the 2004 ABLM Program. In general, concentrations were low relative to the ERL and ERM values. However, the concentration of arsenic slightly exceeded the ERL. These results are similar to the 2003 ABLM program where the same six metals were detected, however both arsenic and copper slightly exceeded their respective ERLs in 2003. There were no PAHs, PCBs, or pesticides found above the detection limit in Batiquitos Lagoon. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was 0.124 in 2004, which was intermediate among the other coastal embayments assessed. This value exceeded the threshold of 0.10 established by Long et al. (1998). Sediments with mean ERM-Q values above this threshold have an increased probability of producing adverse biological effects compared to sediments with ERM-Qs below the threshold. Although the threshold was exceeded, it should be noted that the concentrations of all metals assessed were low in Batiquitos Lagoon, 4 to 12 times lower than their respective ERMs. This is similar to the 2003 results where the mean ERM quotient was 0.152. Toxicity. The percent survival of E. estuarius exposed to Batiquitos Lagoon sediments in a 10-day acute toxicity test was 67% (Table 6-16). Percent survival was significantly different from that of the Control (99%), suggesting that sediments from Batiquitos Lagoon were toxic to the test organisms. Toxicity was also reported in 2003. The source of the toxicity in both years was unknown. Benthic Community Structure. A total of 2864 organisms were collected from Batiquitos Lagoon, representing 53 taxa (Table 6-16). During the 2003 ABLM program a total of 918 organisms were collected, representing 27 taxa. Taxa abundance and richness were lower at Site 3M-1 in the middle of the inner stratum than the other sites assessed in 2004, but the other indices were similar among sites. Based on the benthic community indices, the benthic community structure at Batiquitos Lagoon had a rank of 2 relative to the other embayments where a rank of 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. Three taxa dominated the infaunal community in Batiquitos Lagoon: Barleeia sp, which accounted for 50.9% of the community, Acteocina inculta, which accounted for 16.6% and Grandidierella japonica accounted for 7.9% of the organisms collected (Table 6-17). Barleeia sp. is a genus of barley snail that is a very common intertidal gastropod found throughout southern California and was the seventh most common taxon of all the embayments assessed. The sea slug, A. inculta, was the sixth most abundant species among all the embayments assessed. The gammarid amphipod, G. japonica, was the most commonly found organism in the study. During the 2003 ABLM program Barleeia sp, was also the most dominant species and accounted for 21.2% of the community. Table 6-17. Dominant infaunal species found in the Batiquitos Lagoon during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Barleeia sp Mollusca 1459 50.9 Acteocina inculta Mollusca 475 16.6 BL Grandidierella japonica Crustacean 227 7.9 Values were calculated from the total of all sites assessed. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-33 Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Batiquitos Lagoon were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 6-10. For Batiquitos Lagoon, the relative ranks were 6 for chemistry, 10 for toxicity, and 2 for benthic community structure. 6.4.3.3 Summary and Conclusions Sediments in Batiquitos Lagoon were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size). Two sites (3L-1 and 3M-1) were located in the inner stratum of the Lagoon while the third was in the middle stratum, 2R-1. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that six metals common to all of the embayments assessed were also found in Batiquitos Lagoon. Concentrations were low compared to published values, but arsenic exceeded the ERL. The mean ERM-Q for Batiquitos Lagoon, based on these constituents was 0.124, which was intermediate among the other coastal embayments assessed. This value exceeded the threshold of 0.10, which may indicate an increased probability of producing adverse biological effects. However, concentrations of all metals were low four to 12 times less than their respective ERMs. There were no PAHs, PCBs, or pesticides found above the detection limit in Batiquitos Lagoon. The percent survival of test organisms exposed to sediments from Batiquitos Lagoon was significantly less than that of the control, suggesting the presence of toxic elements in the Lagoon. However, analyses of benthic community indices suggested that the biotic community in Batiquitos Lagoon was good compared to the other embayments. Three taxa dominated the infaunal community in Batiquitos Lagoon: the barley snail, Barleeia sp, the sea slug, Acteocina inculta, and the gammarid amphipod, G. japonica. For Batiquitos Lagoon, the relative ranks were 6 for chemistry, 10 for toxicity, and 2 for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Batiquitos Lagoon had an overall rank of six. During the 2003 ABLM program the Lagoon had an overall rank of eight. A decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 0 2 4 6 8 10 12 Chemistry Toxicity Benthos RankingFigure 6-10. Relative rankings for sediment in Batiquitos Lagoon. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-34 6.4.4 Results and Discussion for San Elijo Lagoon 6.4.4.1 Phase I Results and Discussion Sediment samples were collected in San ELijo Lagoon for the ABLM Program on June 4, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 6-11. The grain size distribution was relatively similar at all sites and there were no strong spatial patterns apparent between the three strata of the Lagoon. Median grain size was lowest in stratum 2, near the middle of the Lagoon (23.1 μm at Site 2L-1) and highest in stratum 1 (175 μm at Site 1R-1) (Table 6-18). The percentage of fine grained sediments among sites followed the same pattern. Sand was the dominant size class at all of the nine sites sampled. The outer stratum had the highest percentage of sand content and the lowest TOC content in the lagoon. TOC content ranged from 0.05% at Site 1R-1 to 3.36% at Site 3R-1. Of the three sites selected for Phase II assessment in San Elijo Lagoon, two were located in the inner stratum of the Lagoon (Sites 3L-2 and 3R-1), and one was located in the middle stratum (Site 2L-1) (Table 6-18). Table 6-18. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at San Elijo Lagoon. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II SEL-1L-1 0.01 79.8 10.2 10.0 96.5 62.4 20.20 0.62 3 2 5 SEL-1M-1 0.29 80.0 9.37 10.30 103 63 19.67 0.66 2 3 5 SEL-1R-1 0.00 98.9 0.5 0.6 175.0 178.4 1.12 0.05 1 1 2 SEL-2L-1 0.04 39.3 34.3 26.4 23.1 12.0 60.62 1.64 9 6 15 * Yes SEL-2M-1 0.17 47.9 27.1 24.8 50.98 13.59 51.92 1.26 7 4 11 SEL-2R-1 1.22 53.1 19.6 26.0 79.7 18.7 45.67 1.73 5 7 12 SEL-3L-2 0.32 51.7 27.2 20.8 70 19.9 47.95 2.84 6 8 14 * Yes SEL-3M-1 0.57 56.3 22.6 20.6 92.4 22.98 43.15 1.53 4 5 9 SEL-3R-1 1.88 41.2 26.1 30.8 20.8 12.7 56.88 3.36 8 9 17 * Yes Mean of all Sites 0.50 60.92 19.66 18.91 79.02 44.79 38.58 1.52 St. Dev. 0.64 20.48 10.83 9.86 46.98 54.02 20.17 1.06 Figure 6-11. Map of Phase I site locations in San Elijo Lagoon. Sites with yellow triangles were selected for Phase II assessment. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-35 6.4.4.2 Phase II Results and Discussion The three sites selected in the San Elijo Lagoon as part of Phase I were sampled in Phase II on July 7, 2004. Sediments from Sites 2L-1, 3L-2 and 3R-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 6-19. Table 6-19. Summary of chemistry, toxicity, and benthic community structure in San Elijo Lagoon. CHEMISTRY* TOXICITY*BENTHIC COMMUNITY Analyte ERL ERM Result ERM- Q Percent Survival Index 2L-1 3L-2 3R-1 Mean St. Dev. Total METALS (mg/kg) Abundance 1277 4 49 443 722 1330 Antimony NA NA <1.74 NA Richness 11 3 3 5.7 4.62 14 Arsenic 8.2 70 3.52 0.050 Diversity 1.03 1.04 0.60 0.89 0.25 NA Cadmium 1.2 9.6 0.33 0.034 Evenness 0.43 0.95 0.55 0.64 0.27 NA Chromium 81 370 15.3 0.041 Dominance 2 2 1 1.7 0.58 NA Copper 34 270 17.8 0.066 Lead 46.7 218 12.7 0.058 Nickel 20.9 51.6 5.89 0.114 Selenium NA NA <1.74 NA Zinc 150 410 51.5 0.126 Mean ERM- Q 0.070 88 % Not Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, seven of the metals assessed were detected above the detection limit in sediments from San Elijo Lagoon: arsenic, cadmium, chromium, copper, lead, nickel, and zinc (Table 6-19). Concentrations of all metals were low and none exceeded their respective ERL or ERM. During the 2003 ABLM program all nine of the metals assessed were detected above the detection limit including arsenic, chromium, copper, lead, nickel, zinc, cadmium, antimony, and selenium. Concentrations of all metals detected during 2003 were low and below their respective ERL or ERM. There were no PAHs, PCBs, or pesticides found above the detection limit in San Elijo Lagoon. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was 0.070 in 2004, which is below the threshold of 0.10. Sediments with mean ERM-Q values below this threshold have a lower probability of producing adverse biological effects than those with ERM-Qs above the threshold (Long et al. 1998). In 2003 the mean ERM quotient was 0.116, which was above the threshold of 0.10. Toxicity. The percent survival of E. estuarius exposed to San Elijo Lagoon sediments in a 10-day acute toxicity test was 88% (Table 6-19). Percent survival was not significantly different from that of the Control (99%), suggesting that San Elijo Lagoon sediments were not toxic to the test organisms. During the 2003 ABLM program toxicity was observed, but the source of toxicity was unknown. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-36 Benthic Community Structure. A total of 1330 organisms were collected from San Elijo Lagoon, representing 14 taxa (Table 6-19). During the 2003 ABLM program a total of 97 organisms were collected, representing 5 taxa. Site 2L-1 in the middle Lagoon was very different from the other sites assessed in 2004 because of the high number of organisms found there. Based on these indices, the benthic community structure at San Elijo Lagoon had a rank of 7 where 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. The low relative ranking is likely due to the lack of organisms found at Site 3L-2. The polychaete, Polydora nuchalis, dominated the benthic community in San Elijo Lagoon, accounting for 62.3% of all the animals collected (Table 6-20). This was the sixth most common taxon found in all of the embayments monitored in the ABLM Program. The gammarid amphipod, G. japonica, was also found in the lagoon, accounting for 25.1% of the community. The third most common species was the mollusk, Tryonia imitator, at 6.9%. During the 2003 ABLM program the barley snail Barleeia sp. was the most dominant species accounting for 50.5% of all animals collected. Table 6-20. Dominant infaunal species found in the San Elijo Lagoon during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition SEL Polydora nuchalis Polychaeta 829 62.3 Grandidierella japonica Crustacean 334 25.1 Tryonia imitator Mollusca 92 6.9 Values were calculated from the total of all sites assessed. Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for San Elijo Lagoon were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 6-12. For San Elijo Lagoon, the relative ranks were two for chemistry, five for toxicity, and seven for benthic community structure. 6.4.4.3 Summary and Conclusions Sediments in San Elijo Lagoon were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size): Site 2L-1 in the middle stratum, and 3L-2 and 3R-1 in the inner stratum. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The 0 1 2 3 4 5 6 7 8 Chemistry Toxicity Benthos RankingFigure 6-12. Relative rankings for sediment in San Elijo Lagoon. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-37 results of the chemistry assessment indicated that seven metals assessed were found in the Lagoon sediments, but none exceeded its respective ERL value. The mean ERM-Q for San Elijo Lagoon was 0.070, which did not exceed the published threshold value of 0.10 and therefore does not suggest the potential for increased toxicity. There were no PAHs, PCBs, or pesticides found above the detection limit in San Elijo Lagoon. Percent survival of test organisms exposed to San Elijo Lagoon sediments was not significantly different from that of the control. Benthic community indices suggested that the biotic community in the Lagoon sediments ranked low compared to other embayments in San Diego County. This was primarily due to the lack of organisms found at Site 3L-2, which is located in the inner-most part of the Lagoon and receives minimal tidal flushing. The infaunal community was dominated by polychaete worms and gammarid amphipods. For San Elijo Lagoon, the relative ranks were two for chemistry, five for toxicity, and seven for benthic community structure. Compared to the other embayments in the 2004 ABLM program, San Elijo Lagoon had an overall rank of three. During the 2003 ABLM program the Lagoon had an overall rank of eleven. A decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 6.5 WMA Assessment Agua Hedionda Agua Hedionda Creek was assessed in order to identify water quality issues within the watershed and to develop short and long-term planning actions to address these issues. The assessment included chemistry and toxicity data collected during storm events from a MLS on Agua Hedionda Creek, chemistry data collected during dry weather, and stream bioassessment IBI ratings. Constituent of concern criteria were developed to prioritize COC for each watershed. The watershed management area assessment methods, discussed in Section 3.4, were applied to these data to determine the constituents of concern and to develop a frequency of occurrence ranking (high, medium, or low). Constituent exceedances in wet and dry weather are summarized in Table 6-21. The cumulative column shows the frequency of occurrence during the past four monitoring seasons. The IBI rating was assigned based on the average of the IBI scores of non reference bioassessment sites in the watershed. In Agua Hedionda Creek, four constituents were identified as having a high frequency of occurrence and were assigned three diamonds. These constituents include: • Total suspended solids • Turbidity • Fecal Coliform • Enterococcus TSS, turbidity and fecal coliform received three diamonds based on Criterion No. 1 and enterococcus was assigned three diamonds based on Criterion No. 3. Two constituents were identified as having a medium frequency of occurrence and were assigned two diamonds based on Criterion No. 5. These constituents include: • Total dissolved solids • Diazinon Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-38 Four constituents had a low frequency of occurrence and were given one diamond. These constituents include: • pH • Ammonia • COD • Total Coliform BOD and COD (along with pH) are unique among the COC assessed in the storm water program because they provide an indirect measure of actual constituents in the water (as opposed to, for example, metals or bacteria). Both represent the reduction of oxygen available in the water column due to other factors, including anthropogenic contaminants as well as natural processes. The presence of BOD or COD above their respective water quality criteria indicate the presence of these contaminants of processes that may have caused the exceedance. Thus, management actions aimed at reducing BOD or COD may be most effective if the source or sources of the elevated levels are addressed directly. In this way, a reduction in BOD or COD levels would be a by-product of actions taken against more easily rectified, tractable COC. Persistent toxicity is evident when more than 50% of the toxicity tests conducted on any species have a NOEC of less than 100%. Even though toxicity testing in Agua Hedionda Creek showed evidence of toxicity during all monitoring seasons, there was no evidence of persistent toxicity. The cumulative IBI scores from bioassessment monitoring at both sites in Agua Hedionda Creek were very poor, indicating evidence of benthic alteration. Figure 6-13 illustrates the number of exceedances for each monitoring season for six categories of constituents, including conventional parameters, nutrients, bacteria, pesticides, metals and toxicity. The stacked bar charts were developed using the number of exceedances from values in Table 6-22 for each constituent category. This displays a conceptual picture of water quality concerns in the watershed over time. Agua Hedionda Creek has had numerous exceedances throughout the monitoring period with the most number of exceedances occurring during the 2002-2003 season. The number of exceedances has decreased since the 2002-2003 season. Conventional parameters, such as TDS, TSS, and turbidity, constituted the most number of exceedances during 2003-2004 and 2004-2005, followed by bacteriological parameters. During 2001-2002 and 2002-2003, bacteriological parameters constituted the most number of exceedances. There were pesticide exceedances during all four seasons, however the number has decreased since 2002-2003. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-39 Table 6-21. Constituent exceedances in Agua Hedionda Creek. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters pH 0 0 0 0 0 0 0 0 0 0 2 18 ♦ 8 Conductivity 0 0 0 0 0 0 0 0 0 0 1 9 - - BOD 0 0 0 0 1 33 1 33 2 17 NA NA - - COD 0 0 0 0 2 67 1 33 3 25 NA NA ♦ 9 Total Dissolved Solids 2 67 2 67 2 67 2 67 8 67 NA NA ♦♦ 5 Total Suspended Solids 2 67 3 100 2 67 3 100 10 83 NA NA ♦♦♦ 1 Turbidity 1 33 3 100 3 100 3 100 10 83 0 0 ♦♦♦ 1 Nutrients Ammonia/Un-ionized Ammonia 0 0 0 0 0 0 0 0 0 0 5 45 ♦ 8 Total Phosphorus 0 0 0 0 1 33 1 33 2 17 NA NA - - Bacteriological Total Coliform 0 0 3 100 0 0 2 67 5 42 3 25 ♦ 8 Fecal Coliform 3 100 3 100 3 100 3 100 12 100 2 17 ♦♦♦ 1 Enterococcus 3 100 3 100 1 33 2 67 9 75 2 17 ♦♦♦ 3 Pesticides Chlorpyrifos 0 0 1 33 1 33 0 0 2 17 0 0 - - Diazinon 3 100 3 100 1 33 1 33 8 67 0 0 ♦♦ 5 Total Metals Copper 0 0 1 33 0 0 0 0 1 8 NA NA - - Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 96-hour 0 0 1 33 0 0 0 0 1 8 NA NA No Ceriodaphnia 7-day survival 0 0 3 100 0 0 0 0 3 25 NA NA No Ceriodaphnia 7-day reproduction 0 0 2 67 0 0 0 0 2 17 NA NA No Hyalella 96-hour 1 33 2 67 1 33 1 33 5 42 NA NA No Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? Agua Hedionda Creek, at Melrose Rd. Very Poor Poor Very Poor Very Poor Very Poor NA Agua Hedionda Creek, at El Camino Real Very Poor Very Poor Very Poor Very Poor Very Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-40 Agua Hedionda Creek Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 6-13. Stacked bar chart of the number of wet weather exceedances of constituent groups in Agua Hedionda Creek. Evaluation of scatterplots for Agua Hedionda Creek presented in Appendix C indicate statistically significant increasing trends for fecal coliform (R2=0.29), TSS (R2=0.44), and turbidity (R2=0.44), which were identified as high frequency COC, and COD (R2=0.34), which had a low frequency of occurrence. Increasing trends were also evident for TKN (R2=0.23), total phosphorus (R2=0.30), dissolved phosphorus (R2=0.25) and total lead (R2=0.26). Although these constituents have not been identified as COC, the significant upward trends may be indicative of persistent WQO exceedances in the future and should be addressed before the parameters become constituents of concern. The increasing trend for TKN correlates with the increasing trend and persistent exceedances for fecal coliform, possibly indicating high levels of sewage within the watershed. Conductivity was the only parameter to indicate a decreasing trend (R2=0.31) in Agua Hedionda Creek. Triad Decision Matrix The data from wet and dry weather, toxicity and bioassessment monitoring efforts were evaluated for this watershed using the triad decision matrix. The triad decision matrix incorporates the chemistry data from wet and dry weather events with the toxicity and bioassessment results to provide indications of pollutant loading, potential impacts to organisms and the ecological health of the watershed. The triad assessment presents possible conclusions about the watershed and provides possible actions or decisions for future monitoring and assessment. Table 6-22 summarizes these results. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-41 Table 6-22. Decision matrix result for Agua Hedionda Creek. Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions Persistent exceedances of water quality objectives (high frequency COC identified) No persistent evidence of toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source identification as a high priority. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. 5) TIE would not provide useful information with no evidence of toxicity. Based on the triad matrix, there was evidence of persistent water quality objective exceedances in TSS, turbidity, and fecal coliform, no evidence of persistent toxicity, and indications of benthic alteration. The recommended actions for Agua Hedionda Creek are to continue monitoring for all elements of the program to gather additional data for assessment and long-term trend analysis and to initiate upstream source identification to determine sources of constituents of concern. In addition, the role of physical habitat disturbance should be investigated. Escondido Creek Escondido Creek was assessed in order to identify water quality issues within the watershed and to develop short and long-term planning actions to address these issues. The assessment included chemistry and toxicity data collected during storm events from a MLS on Escondido Creek, chemistry data collected during dry weather, and stream bioassessment IBI ratings. Constituent of concern criteria were developed to prioritize COC for each watershed. The watershed management area assessment methods, discussed in Section 3.4, were applied to these data to determine the constituents of concern and to develop a frequency of occurrence ranking (high, medium, or low). Constituent exceedances in wet and dry weather are summarized in Table 6-23. The cumulative column shows the frequency of occurrence during the past four monitoring seasons. The IBI rating was assigned based on the average of the IBI scores of non reference bioassessment sites in the watershed. In Escondido Creek, four constituents were identified as having a high frequency of occurrence. These constituents include: • Total dissolved solids • Fecal Coliform • Turbidity • Total Coliform One constituent had a medium frequency of occurrence and was assigned two diamonds based on Criterion No. 5. This constituent was: • Enterococcus Two constituents were identified as having a low frequency of occurrence and were assigned one diamond. These constituents include: • Nitrate • Total suspended solids Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-42 Table 6-23. Constituents of concern measured at Escondido Creek. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters BOD 0 0 0 0 1 33 0 0 1 8 NA NA - - COD 0 0 0 0 1 33 0 0 1 8 0 0 - - Total Dissolved Solids 3 100 3 100 3 100 3 100 12 100 NA NA ♦♦♦ 1 Total Suspended Solids 0 0 2 67 0 0 1 33 3 25 NA NA ♦ 9 Turbidity 2 67 3 100 3 100 1 33 9 75 10 40 ♦♦♦ 3 Nutrients Un-Ionized Ammonia as N 0 0 0 0 0 0 1 33 1 8 0 0 - - Nitrate as N 0 0 0 0 0 0 0 0 0 0 3 13 ♦ 8 Orthophosphate NA NA NA NA NA NA NA NA NA NA 2 4.8 - - Bacteriological Total Coliform 1 33 2 67 2 67 1 33 6 50 14 61 ♦♦♦ 3 Fecal Coliform 3 100 3 100 3 100 3 100 12 100 1 4.4 ♦♦♦ 1 Enterococcus 1 33 3 100 3 100 1 33 8 67 0 0.0 ♦♦ 5 Pesticides Chlorpyrifos 0 0 1 33 0 0 0 0 1 8 0 0 - - Diazinon 3 100 2 67 0 0 0 0 5 42 0 0 - - Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 96-hour 1 33 0 0 0 0 0 0 1 8 NA NA No Ceriodaphnia 7-day survival 2 67 0 0 0 0 0 0 2 17 NA NA No Ceriodaphnia 7-day reproduction 1 33 0 0 0 0 0 0 1 8 NA NA No Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? Escondido Creek, at Harmony Grove Very Poor Very Poor Very Poor Very Poor Very Poor NA Escondido Creek, at Elfin Forest (DS) Poor Poor Very Poor Poor Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS Total dissolved solids (TDS) is a measure of the inorganic salts and small amounts of organic matter dissolved in water (passing through a 0.45 micron filter). The principal constituents are typically the cations calcium, magnesium, sodium and potassium as well as the anions carbonate, bicarbonate, chloride, sulfate, and nitrate. In surface waters, sources of TDS are ubiquitous and elevated levels can originate from natural sources, waste water, and urban and agricultural runoff. During a storm event, flows associated with any of these sources may contribute to elevated TDS levels in storm water runoff. Surfacing groundwater flows and water imported to the watershed may also influence TDS values observed at the MLS. The concentration of TDS in imported water often exceeds 500 mg/L (303(d) Workgroup, 2002). In addition, the results of the wet weather monitoring suggest that elevated TDS Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-43 levels are common and not associated with any particular land use (MEC-Weston 2005). Thus, the pattern of elevated TDS levels during storm events at the Escondido Creek MLS is similar to that observed at other sites monitored throughout San Diego County. Persistent toxicity is evident when more than 50% of the toxicity tests conducted on any species have a NOEC of less than 100%. Toxicity testing in Escondido Creek only showed evidence of toxicity during the 2001-2002 storm season. Therefore, there is no evidence of persistent toxicity. IBI scores from bioassessment monitoring at the Harmony Grove site were very poor throughout the monitoring period and the IBI ratings from the Elfin Forest site varied between poor and very poor. These results indicate that there is evidence of benthic alteration. Figure 6-14 illustrates the number of exceedances for each monitoring season for six categories of constituents, including conventional parameters, nutrients, bacteria, pesticides, metals and toxicity. The stacked bar charts were developed using the number of exceedances from values in Table 6-24 for each constituent category. This displays a conceptual picture of water quality concerns in the watershed over time. Escondido Creek has had numerous exceedances throughout the monitoring period with the most number of exceedances occurring during the 2001-2002 and 2002-2003 seasons and the least number occurring during 2004-2005. Water quality exceedances have steadily decreased since 2002-2003. Conventional parameters, such as TDS and turbidity, constituted the most number of exceedances during all four monitoring seasons, followed by bacteriological constituents. There were pesticide exceedances during the first two monitoring years but not during the last two years. Nutrient exceedances only occurred during the 2004-2005 monitoring season. Escondido Creek Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 6-14. Stacked bar chart of the number of wet weather exceedances of constituent groups in Escondido Creek. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-44 Triad Decision Matrix The data from wet and dry weather, toxicity and bioassessment monitoring efforts were evaluated for this watershed using the triad decision matrix. The triad decision matrix incorporates the chemistry data from wet and dry weather events with the toxicity and bioassessment results to provide indications of pollutant loading, potential impacts to organisms and the ecological health of the watershed. The triad assessment presents possible conclusions about the watershed and provides possible actions or decisions for future monitoring and assessment. Table 6-24 summarizes these results. Table 6-24. Decision matrix results for Escondido Creek. Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions Persistent exceedances of water quality objectives (high frequency COC identified) No persistent evidence of toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source identification as a high priority. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. 5) TIE would not provide useful information with no evidence of toxicity. Based on the triad matrix, there was evidence of persistent water quality objective exceedances in turbidity, TDS and total and fecal coliform, no evidence of persistent toxicity, and indications of benthic alteration. The recommended actions for Escondido Creek are to continue monitoring for all elements of the program to gather additional data for assessment and long-term trend analysis and to initiate upstream source identification to determine sources of constituents of concern. In addition, the role of physical habitat disturbance should be investigated. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Carlsbad WMA The water quality priority ratings presented in Table 6-25 are based on the methodology presented in the BLTEA report (WESTON, MOE, & LWA 2005) and are presented in the Methods Section 3.4. Constituent groups and stressor groups are given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicate that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on current results presented in this 2004-2005 annual report and data from the following programs: • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Co-permittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303d Listing Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-45 Table 6-25. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Carlsbad WMA. Priority Ratings* Constituent Groups Stressor Groups Watersheds/Sub-watersheds Percentage of Total Area Heavy Metals Organics Oil and Grease Sediments Pesticides Nutrients Gross Pollutants Bacteria/ Pathogens Benthic Alterations Toxicity Carlsbad WMA 100% C D D A C B D A B C Loma Alta HA (904.10) 5% C D D D D A A A D D Buena Vista HA (904.20) 11% C D D A C A C A A D Agua Hedionda HA (904.30) 14% C D D A B D D A A C Encinas HA (904.40) 3% C D C D D C B B D D San Marcos HS (904.50) 28% C D D D C C D A C B Escondido Creek HA (904.60) 40% D D D A B A D A A D Notes: * = Rating Calculated Based on Area Weighted Averages of Score Value from the sub-watershed areas. ** = Priority Level (Highest-A to Lowest-D) The purpose of the BLTEA ratings is to identify water quality priorities within a watershed based on weighted averages of the sub-watershed ratings. Because it is a weighted average, larger sub-watersheds will have a greater influence in the overall watershed rating. Sediments and bacteria were the highest priority constituents for the Carlsbad WMA and were given an A rating followed by nutrients and benthic alteration which were given a B rating. All other constituents were given either a C or D rating. For the Loma Alta sub-watershed which accounts for 5% of the Carlsbad WMA, high priority (A) ratings were given for nutrients, gross pollutants, and bacteria. For the Buena Vista sub-watershed which accounts for 11% of the Carlsbad WMA, high priority (A) ratings were given for sediments, nutrients, bacteria, and benthic alteration. For the Agua Hedionda sub-watershed which accounts for 14% of the Carlsbad WMA, high priority (A) ratings were given for sediments, bacteria, and benthic alteration. For the San Marcos sub-watershed which accounts for 28% of the Carlsbad WMA, only bacteria received a high priority (A) rating followed by toxicity which was given a B rating. In the Escondido Creek sub- watershed which accounts for 40% of the Carlsbad WMA, high priority (A) ratings were given for sediments, nutrients, bacteria, and benthic alteration followed by pesticides which were given a B rating. The Encinas sub-watershed, which represents 3% of the Carlsbad WMA, did not receive any high priority (A) ratings for any constituent group. A regional evaluation and description of the BLTEA is presented in the Regional Assessment Section 13. The complete tables used to calculate the ratings are presented in Appendix G. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-46 6.6 Conclusions and Recommendations The Carlsbad watershed is the third most densely populated watershed in the San Diego region. For the Agua Hedionda sub-watershed which accounts for 11% of the Carlsbad watershed, land use within the contributing runoff area is primarily residential (33%), undeveloped (25%), and agriculture (11%). For Agua Hedionda Creek, TSS, turbidity, fecal coliform, and enterococcus were identified as high frequency of occurrence COC, TDS and diazinon were identified as medium frequency of occurrence COC, and pH, COD, ammonia, and total coliform were identified as low frequency of occurrence COC. For the Escondido Creek sub-watershed which accounts for approximately 33% of the Carlsbad watershed, land use within the contributing runoff area is predominantly undeveloped (35%), residential (25%), and parks (16%). For Escondido Creek, TDS, turbidity, total coliform, and fecal coliform were identified as high frequency of occurrence COC, enterococcus was identified as a medium frequency of occurrence COC, and TSS and nitrate were identified as low frequency of occurrence COC. In Agua Hedionda Creek, increasing trends were observed for fecal coliform, TSS, turbidity, COD, TKN, total and dissolved phosphorus and total lead. Third party data collected in 2002 under SWAMP, indicated that sulfate, manganese and toxicity were consistent problems throughout the Carlsbad watershed. The sources of the water quality problems in the watershed are unknown but likely come from several disperse sources. The water quality concerns were highlighted by poor and very poor ratings of the macroinvertebrate communities in the streams. Four lagoons within the Carlsbad watershed were monitored in the Ambient Bay and Lagoon Monitoring Program, including Buena Vista, Agua Hedionda, Batiquitos and San Elijo Lagoons. For Buena Vista Lagoon, the relative ranks were nine for chemistry, one for toxicity, and nine for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Buena Vista Lagoon had an overall rank of seven. The relative ranks for Agua Hedionda Lagoon were five for chemistry, seven for toxicity, and six for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Agua Hedionda Lagoon had an overall rank of six. For Batiquitos Lagoon, the relative ranks were 6 for chemistry, 10 for toxicity, and 2 for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Batiquitos Lagoon had an overall rank of six. For San Elijo Lagoon, the relative ranks were two for chemistry, five for toxicity, and seven for benthic community structure. Compared to the other embayments in the 2004 ABLM program, San Elijo Lagoon had an overall rank of three. The relative quality in all lagoons within the Carlsbad watershed increased compared to the 2003 ABLM rankings. The WMA assessment findings agreed with the BLTEA rating priorities, which found sediments and bacteria to be high priority (A rating) constituents followed by nutrients and benthic alteration which were given a B rating. The information provided from the triad matrix results used in conjunction with the BLTEA ratings can assist the jurisdictions in making informed decisions in developing their WURMP programs. The two reports also allow for an evaluation of where data gaps exist and where efforts should be targeted. Utilizing the BLTEA rating methods for future data evaluations would also allow for long term BMP effectiveness assessment. Incorporation of additional useable data from other third party sources such as POTWs and non-profit organizations would also help to increase the confidence of the BLTEA ratings and overall WMA assessments. Carlsbad WMA SECTION 6 2004-2005 Urban Runoff Monitoring Report 6-47 Recommendations for the Carlsbad watershed are to continue monitoring to gather additional data for assessment and long-term trend analysis and to initiate upstream source identification to determine sources of constituents of concern. In addition, the role of physical habitat disturbance should be investigated. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-1 7.0 SAN DIEGUITO RIVER WATERSHED MANAGEMENT AREA 7.1 Monitoring Site Descriptions The San Dieguito River watershed management area includes the San Dieguito River watershed (HU 905.00), which consists of five hydrologic areas: Solana Beach, Hodges, San Pasqual, Santa Maria Valley, and Santa Ysabel. The watershed includes San Dieguito River, Santa Ysabel Creek, and Santa Maria Creek. The San Dieguito Slough is the only coastal lagoon in this watershed. The San Dieguito River watershed covers over 221,000 acres and includes portions of the following cities: Del Mar, Escondido, Poway, San Diego, Solana Beach, and unincorporated areas of San Diego County (Figure 7-1). Land use in the watershed is a mix of primarily residential, parks/open space, agriculture, and vacant/undeveloped land. There are over 118,000 acres of vacant/undeveloped land, of which over 53,000 acres are available for residential development. Population density in the watershed is second smallest for watersheds within the San Diego Region and the population is projected to reach more than 214,000 by 2015. San Dieguito Lagoon, San Dieguito River, reservoirs, and other parts of the watershed provide valuable habitat to a number of threatened and endangered species (Table 7-1). Major impacts affecting this watershed include surface water quality degradation, habitat degradation and loss, and invasive species. Land use activities, including urban runoff, agricultural runoff, and domestic animals, are the primary sources of these impacts. Seven water bodies in this watershed are listed on the SWRCB 2002 303(d) list (Table 7-2). Table 7-1. Beneficial uses within the San Dieguito River watershed. Beneficial Uses Inland Surface Waters Coastal Waters Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z z z Agricultural Supply z z z Industrial Service Supply z z z z Industrial Process Supply z z z Navigation z Contact Water Recreation z z z1 Non-Contact Water Recreation z z z Commercial and Sport Fishing z Biological Habitats of Special Significance z z Warm Freshwater Habitat z z Cold Freshwater Habitat z z Estuarine Habitat z Wildlife Habitat z z z Rare, Threatened, or Endangered Species z z z Marine Habitat z Migration of Aquatic Organisms z Aquaculture Shellfish Harvesting z Spawning, Reproduction and/or Early Development z 1 Shore and boat fishing only. Other REC1 uses prohibited. Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-2 Figure 7-1. San Dieguito River Watershed Management Area. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-3 Table 7-2. Water bodies on the SWRCB 303(d) list in the San Dieguito River watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor Pacific Ocean Shoreline Rancho Santa Fe 905.11 Bacteria Indicators Green Valley Creek Rancho Santa Fe 905.11 Sulfates Lake Hodges Del Dios 905.21 Color, Nitrogen, Phosphorus, TDS Kit Carson Creek Del Dios 905.21 TDS Felicita Creek Felicita 905.23 TDS Cloverdale Creek Highland 905.31 Phosphorus, TDS Sutherland Reservoir Sutherland 905.53 Color Source: SWRCB 2003 The San Dieguito River watershed includes four main reservoirs/lakes: Sutherland, Lake Ramona, Lake Poway, and Lake Hodges. Approximately 86% of the watershed lies behind dams (Coastal Conservancy 2001). Principal aquifers in the watershed include the Santa Maria Basin, San Pasqual Valley Basin, and San Dieguito Valley Basin. Rainfall in the watershed ranges from 10.5 inches along the coast to 31.5 inches in the inland areas (Figure 7-1). The San Dieguito River (SDC) mass loading station is located along a natural channel off Via De La Valle in the City of Del Mar, behind the Morgan Run Golf Course maintenance shop. The contributing runoff area is over 16,380 acres, which makes up 8% of the San Dieguito River watershed land area. This station receives only localized runoff. Lake Hodges captures most of the runoff from the upper watershed. The major land uses within the contributing runoff area are undeveloped (24%), parks (24%), agricultural (18%), and residential (21%). The contributing runoff area is similar to the land use in the entire watershed, which is 42% undeveloped, 15% parks, 18% agricultural and 14% residential. Stream Bioassessment monitoring in the San Dieguito River WMA has occurred at two monitoring sites. The lower monitoring site is located about one-half mile below the Lake Hodges Reservoir. The in- stream habitat quality is fairly good and the riparian zone is mostly undisturbed, but the stream bed in the monitoring reach is dominated by bedrock and lacks the complexity needed for optimal macroinvertebrate colonization. The upper monitoring site is in Green Valley Creek at the West Bernardo Drive crossing. This stream flows into Lake Hodges and the monitoring reach has good riffles with complex cobble and boulder substrate with high colonization potential. San Dieguito River empties into the San Dieguito Lagoon, which is located at the northern edge of the City of Del Mar. The Lagoon consists of a main channel, which runs from the mouth at Del Mar’s Dog Beach to just east of Interstate 5, and a large side channel, which lies south of the main channel and is known as the fishhook. The Lagoon contains 260 acres of wetland habitat, but only 86 acres are characterized as open water (Coastal Conservancy 2000). Three sites were sampled in San Dieguito Lagoon (Figure 7-1). All three sites were located in the fishhook area based on the grain size and total San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-4 organic carbon results of the Phase I survey. The main source of freshwater to the San Dieguito Lagoon is intermittent flow from the San Dieguito River. The Lagoon also receives flow directly from two smaller drainages. Tidal influence to the Lagoon is restricted by sand that can block the mouth for extended periods of time. Historically, sewage was dumped into the Lagoon channels from 1940 to 1974 and there was some light industry in the area from 1942 to 1964. Currently, Del Mar Racetrack and Fairgrounds lie to the north of the Lagoon. Agricultural and residential uses dominate the rest of the immediate area. San Dieguito Lagoon is not on the SWRCB 2002 303(d) List. 7.2 Storm Water Monitoring Summary 7.2.1 2004-2005 Results The San Dieguito River mass loading station was monitored for the fourth consecutive year for a total of 12 storms since 2001. For the 2004-2005 wet season events, monitoring took place on October 17, 2004, February 11 and February 18, 2005. The results for all 12 storms were compared to water quality objectives to identify potential water quality concerns during storm flow (Table 7-3). Fecal coliforms levels exceeded water quality objectives during the October 27, 2004 and February 18, 2005 storm events. Chemical oxygen demand (COD) exceedances were noted during the February 11, 2005 storm event. The value for this parameter was much higher during this storm event than the majority of the other events monitored since 2001. Total dissolved solids (TDS) concentrations exceeded water quality objectives during all three storms monitored during 2004-2005. TDS exceedances are common at this site and other sites that are monitored throughout San Diego County. None of the water quality objectives for pesticides, hardness, total metals, and dissolved metals were exceeded in the 2004-2005 season. The results of the toxicity tests for the 2004-2005 season indicated low toxicity during the three storm events monitored (See Section 3.1.6.2 for details on toxicity testing). Of the five tests that were conducted on samples from all three storm events, only one suggested significant toxicity. The October 17, 2004 sample from San Dieguito River showed toxicity to Ceriodaphnia during the 7-day reproduction test. No toxicity to Ceriodaphnia was expressed in the other two storm events from San Dieguito River and no toxicity to Selenastrum or Hyalella was observed in any of the San Dieguito River samples collected during the 2004-2005 storm season. Table 7-3. Analytes measured at the San Dieguito River mass loading station.11/29/01 1/29/02 2/17/02 2/11/03 2/25/03 3/15/03 2/3/04 2/18/04 3/2/04 10/17/04 2/11/05 2/18/05Electrical Conductivityumhos/cm 3090 3340 3480 277 2700 257 3700 3660 1990 3210 3380 1744Oil And Grease mg/L 15 USEPA Multi-Sector General <1 <1 <1 <1 <1 1.38 <1 <1 <1 <1 <1 <1 0% 0.04pHpH Units 6.5-8.5 Basin Plan 7.6 7.5 7.5 7.83 7.56 7.64 8.005.227.21 7.82 7.70 6.84 0% 0.00Enterococci MPN/100 mL3,000 300 500 17,000 5,000 1,700 7,000 1,300 30,000 140,000 130 1,300Fecal Coliform MPN/100 mL400 Basin Plan 230 80 225,0003007002301300 8000 14,00023050050% 6.37Total Coliform MPN/100 mL230 1,300 170 50,000 3,000 13,000 500 3,000 130,000 300,000 800 3,000Ammonia As N mg/L 0.2 0.13 <0.1 0.52 0.20 0.13 <0.1 0.17 1.7 <0.1 0.17 0.16Un-ionized Ammonia as Nμg/L 25 (a)Basin Plan 9.21 1.82 1.36 1.16 0.01 6.55 1.2 1.9 3.0 0% 0.12Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General 14 3 2.1 15.9 2.51 3.8944.77.46 4.37 21.8 3.33 <2 8% 0.34Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General 34 61 60 51 41 8213857 81 <2512341 17% 0.54Dissolved Organic Carbon mg/L 7.98 10.4 7.67 5.74 61 9.19 35.9 5.42 5.21Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General 0.1 0.05 <0.05 0.11 0.08 <0.05 <0.05 0.2 0.19 0.16 0.13 0.12 0% 0.05Nitrate As N mg/L 10 Basin Plan 0.1 0.2 0.2 0.06 0.40 0.27 0.05 0.13 1.01 0.16 1.67 1.81 0% 0.05Nitrite As N mg/L 1 Basin Plan <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0% 0.03Surfactants (MBAS)mg/L 0.5 Basin Plan <0.5 <0.5 <0.5 <0.1 0.1 <0.1 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0% 0.41Total Dissolved Solids mg/L 500 Basin Plan by watershed1750 1940 2080 1900 1440 1490 2220 2580 1350 2100 1630 982100% 3.58Total Kjeldahl Nitrogen mg/L 2.4 1.35 1.4 0.8 1.4 0.9 0.8 2.8 1.8 1.4 1.6 2Total Organic Carbon mg/L 9.68 8.59 11.0 9.85 83.8 11.2 36.3 9.54 10.9Total Phosphorus mg/L 2 USEPA Multi-Sector General 0.1 0.07 0.08 0.14 0.08 0.12 0.12 0.2 0.3 0.19 0.14 0.45 0% 0.08Total Suspended Solids mg/L 100 USEPA Multi-Sector General 31 <20 <20 10 23 34 <20 4410128 24 28 8% 0.29TurbidityNTU 20 Basin Plan 17.6 3.69 3.12 4.72 17.5 17.730.619.329.76.77 6.01 18.3 17% 0.73Chlorpyrifosμg/L 0.02 CA Dept. of Fish & Game <0.03* <0.03* <0.03* <0.03* <0.03* <0.03*<0.01 <0.01 <0.01<0.01 <0.01 <0.01 0% 0.50Diazinonμg/L 0.08 CA Dept. of Fish & Game <0.03 <0.03 <0.03 <0.03 <0.03 <0.03<0.01 <0.01 0.032<0.01 <0.01 <0.01 0% 0.15Malathionμg/L 0.43 CA Dept. of Fish & Game <0.10 <0.10 <0.10<0.01 <0.01 <0.01<0.01 <0.01 <0.01 0% 0.05HardnessTotal Hardness mg CaCO3/L840 970 1080 1030 726 767935 999 564967 767 487Antimonymg/L 0.006 Basin Plan <0.002 <0.002 <0.002 0.002 0.003 <0.002<0.005 <0.006 <0.005 <0.005 <0.005 <0.0050% 0.34Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan 0.001 0.002 0.003 0.002 0.003 0.0030.007 0.006 0.004 0.006 0.007 <0.0020% 0.08Cadmium mg/L(b)40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.01Chromium mg/L(b)CTR (Cr VI)0.005 0.006 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.00Copper mg/L(b)40 CFR 131 <0.005 <0.005 <0.005 0.014 0.004 <0.0050.012 0.006 0.005 0.005 <0.005 <0.0050% 0.05Lead mg/L(b)40 CFR 131 <0.002 <0.002 <0.002 0.002 <0.002 <0.002<0.002 <0.002 <0.002 0.002 <0.002 <0.002Nickel mg/L(b)/0.1 40 CFR 131/ Basin Plan 0.002 0.002 0.003 0.002 <0.002 0.0030.003 <0.002 <0.002 0.003 0.003 0.0020% 0.00Selenium mg/L 0.02 40 CFR 131 <0.002 <0.002 0.007 <0.004 <0.004 <0.004<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.13Zinc mg/L(b)40 CFR 131 <0.020 <0.020 <0.020 <0.020 0.008 0.005<0.02 <0.02 <0.02 <0.02 <0.02 <0.020% 0.01Antimonymg/L(e)40 CFR 131 <0.002 <0.002 <0.002 <0.002 0.002 0.003<0.005 <0.006 <0.005 <0.005 <0.005 <0.005Arsenic mg/L 0.34 (c)40 CFR 131 0.001 0.002 0.001 0.002 0.002 0.0020.003 0.004 <0.002 <0.002 <0.002 <0.0020% 0.00Cadmium mg/L(b)40 CFR 131 <0.001 <0.001 <0.001 0.002 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.01Chromium mg/L(b)40 CFR 131 <0.005 <0.005 0.007 <0.005 <0.005 <0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.00Copper mg/L(b)40 CFR 131 <0.005 <0.005 <0.005 0.016 0.005 0.0050.005 0.005 <0.005 <0.005 <0.005 <0.0050% 0.04Lead mg/L(b)40 CFR 131 <0.002 <0.002 <0.002 <0.002 <0.002 0.0007<0.002 <0.002 <0.002 <0.002 <0.002 <0.002Nickel mg/L(b)40 CFR 131 <0.002 0.003 0.005 0.002 <0.002 0.0090.003 0.002 0.007 0.003 0.003 0.0020% 0.00Selenium mg/L 0.02 (d)40 CFR 131 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.10Zinc mg/L(b)40 CFR 131 <0.020 <0.020 <0.020 0.086 0.033 <0.020<0.02 <0.02 <0.02 <0.02 <0.02 <0.020% 0.032003-042001-02Dissolved MetalsWQO SOURCEWet ChemistryFrequency Above WQOMean Ratio to WQOTotal MetalsPesticidesBacteriological2004-052002-03ANALYTE UNITSGeneral / Physical / Organic Table 7-3. Analytes measured at the San Dieguito River mass loading station.11/29/01 1/29/02 2/17/02 2/11/03 2/25/03 3/15/03 2/3/04 2/18/04 3/2/04 10/17/04 2/11/05 2/18/052003-042001-02WQO SOURCEFrequency Above WQOMean Ratio to WQO2004-052002-03ANALYTE UNITSCeriodaphnia 96-hr LC50 (%)100 >100 >100 >100 >100 >100 >100 >100 >100 > 100 >100 >100 >100 0% 0.00Ceriodaphnia 7-day survival NOEC (%)100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Ceriodaphnia 7-day reproduction NOEC (%)1006.2510050 12.510050100 100 10025100 100 42% 2.67Hyalella 96-hr NOEC (%)100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Selenastrum 96-hr NOEC (%)100 10050 50100 100 100 10050100 100 100 100 25% 0.50SourcesUSEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Table 3 - Parameter benchmark values.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.ToxicityShaded text – exceeds water quality objective.* Indicates detection limit exceeds water quality objective.USEPA Federal Register Document 40 CFR Part 131, May 18, 2000.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.(e) USEPA has not published an aquatic life criterion value.Blank spaces have been verified and no data is available due to changes in the monitoring program.(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-7 7.2.2 Relationships/Analyses As with many other watersheds in San Diego County, high concentrations of total dissolved solids appear to characterize water quality in the San Dieguito River watershed. The Basin Plan water quality objective for TDS (500 mg/L) has been exceeded for this WMA during all storm events since 2001 with values ranging from 982 to 2,580 mg/L. Other water quality concerns such as fecal coliform, BOD, COD, pH, TSS, and turbidity have appeared only sporadically in storm water runoff since 2001. Evaluation of scatterplots (presented in Appendix C) for San Dieguito River indicate that there are slight increasing trends for nitrate (R2=0.37), total phosphorus (R2=0.43), and dissolved phosphorus (R2=0.35) and a decreasing trend for total chromium (R2=0.35). Toxicity testing has been performed on storm water for the past 4 years or 12 events (See Section 3.1.6.2 for details on toxicity testing). Even though storm water was toxic to Ceriodaphnia in the 7-day reproduction test in 5 out of 12 storm events (42%) and to Selenastrum (96-hr) in 3 out of 12 storm events (25%), persistent toxicity was not observed within San Dieguito River. Toxic responses in the Ceriodaphnia reproduction test were observed in 5 of the 12 storm events; however none of the COC showed a significant relationship with this toxicity based on the chi-square test. Likewise, there were no co-occurrences of COC above the water quality objectives with toxicity to Selenastrum. In order to illustrate the magnitude of the water quality exceedances for 2004-2005, the ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern. The results are shown in Figure 7-2. The largest single exceedance was for fecal coliform, which exceeded the WQO by 35 times during the October 17, 2004 storm. There were also noticeable single exceedances for TDS, which exceeded the WQO by 4.2 times on October 17, 2004 and over 3.3 times during the February 11, 2005 storm event. The average magnitude of water quality exceedances was also determined for each constituent by calculating the mean ratio of water quality results to the WQOs from all storm events from October 2001 through April 2004. Mean ratios are illustrated in Figure 7-2. The largest average exceedance for the period of record was for fecal coliform (4.4 times the WQO). Other notable average exceedances were for TDS (3.7 times the WQO) and the Ceriodaphnia reproduction test (2.7 times the WQO). In addition to the wet weather monitoring discussed above, there are 30 sites in the San Dieguito River WMA where water quality is monitored during dry weather. Of these, only three are located upstream of the mass loading station on San Dieguito River. The dry weather data for this site is useful, but it is important to remember that it represents only one year of monitoring (See Section 3.4 for details on dry weather sampling). San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-8 TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 20 40 Ratio to WQOMean Ratio (Oct 01 to Apr 04) 10/17/04 2/11/05 2/18/05 Above WQO Figure 7-2. San Dieguito River water quality ratios. Table 7-4 shows exceedances of the action levels and the ratios of exceedances for COC that were measured during the 2004 dry weather monitoring program. During dry weather sampling, there was one exceedance of dry weather criteria for both total coliform and turbidity. During the 2004-2005 monitoring season, there were no COC in common between the wet and dry weather monitoring programs. A map for the WMA showing DWS exceedances is found in Figure 7-3. Pie symbols appear at dry weather stations that have had water quality exceedances. The colored slices of the pie show the different constituent groups that contributed to the exceedances. Table 7-4. San Dieguito River WMA 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* St. Dev. Ratio of Exceedance Turbidity 1 3 0.91 0.81 Total Coliform 1 3 0.60 0.43 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-9 Figure 7-3. San Dieguito River WMA dry weather exceedance map. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-10 7.2.3 TIEs TIE testing was not performed on San Dieguito River samples. This mass loading station has not been identified as a TIE candidate site based upon the Triad Decision Matrix. Toxicity to Ceriodaphnia was observed in only one of the three events. 7.2.4 Summary and Conclusions Elevated levels of TDS during wet weather continues to be the primary water quality concern in the watershed. Other constituents, including BOD, COD, pH, TSS, turbidity, and particularly fecal coliform bacteria, exceeded WQO occasionally and do not appear to be consistently problematic. There were three dry weather monitoring sites located upstream of the mass loading station, but the data suggested that there was no clear link between dry and wet weather constituents. The cause of infrequent toxicity during mass loading station monitoring is unknown. 7.3 Stream Bioassessment Stream bioassessment in the San Dieguito River WMA included two urban affected monitoring sites. The upstream site was in Green Valley Creek at West Bernardo Drive, upstream of Lake Hodges. The downstream site was in the San Dieguito River proper, approximately ½ mile downstream of Lake Hodges along Del Dios Highway. 7.3.1 Results and Discussion Green Valley Creek Monitoring Site: GVC-WB The Green Valley Creek monitoring site had a benthic macroinvertebrate community with Index of Biotic Integrity ratings of Poor and Very Poor for the October 2004 and May 2005 surveys, respectively (Table 7-5) (See Section 3.2 for details on the sampling approach). Taxa richness for the two surveys was variable, with 24 unique taxa collected in October, and 12 collected in May. There were five and three different EPT taxa collected for the October and May surveys, respectively. There were no organisms collected that are highly intolerant to impairment, and the percent highly tolerant taxa comprised 29% of the community in October 2004 and 4% of the community in May 2005. The in-stream habitat of the reach was quite good, with a complex variety of stable niche space for macroinvertebrate colonization. The willow riparian zone was somewhat disturbed, but the stream had good canopy cover. Water quality was fair, with moderately high specific conductance values of 2.442 mS/cm in October and 2.038 mS/cm in May, and pH values of 7.9 for both surveys (Table 7-5). San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-11 Table 7-5. Selected Biological Metrics and Physical Measures of the San Dieguito River WMA. San Dieguito River Watershed Management Area Green Valley Creek at West Bernado Drive (GVC-WB) San Dieguito River on Del Dios Highway (SD-DDH) Survey Oct-04 May-05 Oct-04 May-05 Index of Biotic Integrity/ Qualitative Rating 21 Poor 5 Very Poor 13 Very Poor 17 Poor Metrics Taxa Richness 24 12 20 7 EPT Taxa (mayflies, stoneflies, and caddisflies) 5 3 6 4 % Intolerant Taxa 0% 0% 0% 0.0% % Tolerant Taxa 29% 4% 7% 0% Average Tolerance Value 6.4 5.8 5.9 5.8 % Collector Filterers +Collector Gatherers 45% 94% 85% 100% Physical Measures Elevation 340 170 Physical Habitat Score 109 134 146 168 Riffle Velocity (ft/sec) 0.9 1.2 1.8 1.8 Substrate Composition Silt 5% 2% Sand 5% 10% 2% Gravel 7% 10% 5% Cobble 30% 10% 8% 10% Boulder 17% 22% 2% 17% Roots 6% Bedrock/Solid 36% 48% 88% 60% Water Quality Temperature ºC 17.6 18.9 20.1 17.3 pH 7.9 7.9 8.0 7.8 Specific Conductance (ms/cm) 2.442 2.038 3.059 1.040 Relative Chlorophyll (μg/L) 2.6 3.1 3.0 6.2 The benthic community varied considerably between the October and May surveys. In October, Chironomid midges and the snail, Physa, dominated the community, and in May, the black fly, Simulium, and the mayfly, Baetis, were the dominant organisms (Table 7-6). The damselfly, Argia, was relatively abundant in October, and the microcaddisfly, Hydroptila, was abundant in May. Collector filterers and collector gatherers increased from 45% in October 2004 to 94% in May 2005 (Table 7-5). The San Dieguito Creek mass loading station was too spatially disconnected from Green Valley Creek to correlate any of the storm water information with the benthic community. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-12 Table 7-6. San Dieguito River WMA Community Summary. Taxon Common Name Percent Composition Tolerance Value Functional Feeding Group Chironomidae non-biting midges 22% 6 Collector Gatherer/Filterer Physa snail 19% 8 Scraper Argia dancer damselfly 9% 7 Predator Oligochaeta earthworm 8% 5 Collector Gatherer Oct-04 Fossaria snail 7% 8 Scraper Simulium black fly 62% 6 Collector Filterer Baetis minnow mayfly 23% 5 Collector Gatherer Hydroptila microcaddisfly 6% 6 Piercer Herbivore Chironomidae non-biting midges 3% 6 Collector Gatherer/Filterer Green Valley Creek at West Bernado Drive (GVC-WB) May-05 Ostracoda seed shrimp 2% 8 Collector Gatherer Simulium black fly 33% 6 Collector Filterer Chironomidae non-biting midges 25% 6 Collector Gatherer/Filterer Cheumatopsyche net-spinning caddisfly 11% 5 Collector Filterer Hydroptila microcaddisfly 11% 6 Piercer Herbivore Oct-04 Fallceon quilleri minnow mayfly 5% 4 Collector Gatherer Simulium black fly 75% 6 Collector Filterer Baetis minnow mayfly 16% 5 Collector Gatherer Chironomidae non-biting midges 8% 6 Collector Gatherer/Filterer Fallceon quilleri minnow mayfly 1% 4 Collector Gatherer San Dieguito River on Del Dios Highway (SD-DDH) May-05 Cheumatopsyche net-spinning caddisfly 1% 5 Collector Filterer Del Dios Highway Monitoring Site: SD-DDH The San Dieguito River monitoring site had a benthic macroinvertebrate community with Index of Biotic Integrity ratings of Very Poor in October 2004 and Poor in May 2005 (Table 7-5). Taxa richness was variable, with 20 different taxa collected in October and 7 different taxa collected in May. There were six EPT taxa collected in the October survey and four different EPT taxa collected in the May survey. There were no organisms highly intolerant to impairment, and the percent tolerant taxa was relatively low, comprising 7% of the community in October and 0% of the community in May. Physical habitat of the community was scored in the high end of the sub-optimal range. The reach was dominated by smooth bedrock pools separated by short riffles with little cobble or root structures to provide habitat space. The bedrock also inhibited the development of good bank and riparian vegetation, although the reach was undisturbed and there were mature oak and sycamore stands near the sampling areas. The reach is also subject to heavy growths of filamentous algae in the spring, which inhibits many rock-clinging organisms. Specific conductance was moderately high in October, with a value of 3.059 mS/cm, and was considerably lower in May with a value of 1.040 mS/cm. Values for pH were 8.0 and 7.8 in October 2004 and May 2005, respectively (Table 7-5). The benthic community was dominated by the black fly, Simulium, in both surveys, accounting for 75% of the community in May (Table 7-6). Other constituents of the community showed seasonal variance. Chironomid midges and the caddisflies, Cheumatopsyche and Hydroptila, were abundant in the October survey, and the mayfly, Baetis, was abundant in the May survey. A total of 10 different EPT taxa were collected from both surveys combined, including 9 individuals of the sensitive caddisfly Oxyethira. The greater abundance of Caddisflies in October is likely due to the lack of filamentous algae on the rocky substrates. Simulium, however, has been observed to cling to rocky surfaces as well filamentous algae. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-13 The San Dieguito River mass loading station was located approximately five miles downstream of the bioassessment station on Del Dios Highway, and water quality measures found in storm water may have originated in areas below the bioassessment site. Constituents of concern identified during storm water sampling that would have a negative impact on the biological community included total dissolved solids, total suspended solids, and turbidity (Table 7-3). Pesticides, metals, and toxicity to Ceriodaphnia and Hyalella from storm water were not at high levels. It may be noted that the tolerance of Hyalella is higher than most benthic macroinvertebrates, and overall biological degradation may be quite substantial before Hyalella is impacted by water pollutants. 7.3.2 Summary and Conclusions The San Dieguito River WMA was sampled at two sites, Green Valley Creek at West Bernardo Drive, and San Dieguito River below Lake Hodges in October 2004 and May 2005. The macroinvertebrate community of Green Valley Creek had an Index of Biotic Integrity rating of Poor and Very Poor, with the October survey scoring much higher than the May survey. San Dieguito River was rated Very Poor in October and Poor in May. At the San Dieguito River site, nine individuals of the sensitive caddisfly, Oxyethira, were collected. 7.4 Ambient Bay and Lagoon Monitoring 7.4.1 Results and Discussion 7.4.1.1 Phase I Results and Discussion Sediment samples were collected in San Dieguito Lagoon for the ABLM Program on June 3, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 7-4. San Dieguito Lagoon has a unique area to the south of the main channel known as the fish hook. This area was designated as the middle stratum of the Lagoon based on its position between the mouth of the Lagoon and the extent of tidal influence. The sediment characteristics in the fish hook were different from those in inner and outer strata in the main channel. The median grain size in the middle strata ranged from 20.4 to 239.5 μm (Table 7-7), while the median grain size at sites in the inner and outer strata was much larger, ranging from 79 μm to 157 μm with the exception of Site 3R-1 that had a median grain size of 24.6 μm. The sediments at sites in the middle strata were composed primarily of silt, while those in the inner and outer strata of the main channel were Figure 7-4. Map of Phase I site locations in San Dieguito Lagoon. Sites with yellow triangles were selected for Phase II assessment. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-14 composed primarily of sand except for Site 2L-1 that had a composition of 66.91% sand. The TOC content was also higher in sediments from the middle strata sites (1.23% to 2.03%) compared to the inner and outer sites (0.05% to 1.85%). Because of the high percentage of fine grained sediments and high TOC levels at the middle strata sites, two sites selected for Phase II assessment were taken from this area (2M-1 and 2R-1) and one from the inner stratum, Site 3R-1 (Table 7-7). Table 7-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at San Dieguito Lagoon. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II SDL-1L-1 1.04 60.0 25.1 13.86 79 37.9 39.00 1.27 5 6 11 SDL-1M-1 0.00 76.5 16.25 7.27 94 69 23.53 0.63 3 3 6 SDL-1R-1 0.00 98.8 0.54 0.61 157 161 1.16 0.05 1 1 2 SDL-2L-1 1.16 66.91 15.0 16.9 239.5 42.01 31.93 1.23 4 4 8 SDL-2M-1 0.15 34.6 37.4 27.9 20.4 10.78 65.24 2.03 8 9 17 * Yes SDL-2R-1 0.01 34.4 40.5 25.1 29.7 10.6 65.60 1.43 9 7 16 * Yes SDL-3L-1 0.33 57.5 23.3 18.92 102 29.4 42.21 1.27 6 5 11 SDL-3M-1 0.05 77.0 14.6 8.3 142 93.9 22.99 0.36 2 2 4 SDL-3R-1 0.23 36.8 37.1 25.80 24.6 16.5 62.94 1.85 7 8 15 * Yes Mean of all Sites 0.33 60.27 23.32 16.07 98.67 52.31 39.40 1.12 St. Dev. 0.45 22.25 13.23 9.40 72.37 49.25 22.24 0.66 7.4.1.2 Phase II Results and Discussion The three sites selected in San Dieguito Lagoon as part of Phase I were sampled in Phase II on July 7, 2004. Sediments from 2M-1, 2R-1 and 3R-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 7-8. Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, seven of the nine metals assessed were detected above the detection limit in sediments from San Dieguito Lagoon: arsenic, cadmium, chromium, copper, lead, nickel, and zinc (Table 7-8). These metals were found in all of the embayments monitored in the 2004 ABLM Program. Concentrations of all metals from San Dieguito Lagoon were low and none exceeded their respective ERL or ERM except for cadmium which slightly exceeded the ERL. With the exception of cadmium, the same metals were detected above the detection limit during the 2003 ABLM program. All metal concentrations were low and did not exceed the ERM during 2003. There were no PAHs, PCBs, or pesticides found above the detection limit in San Dieguito Lagoon during 2004. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-15 Table 7-8. Summary of chemistry, toxicity, and benthic community structure in San Dieguito Lagoon. CHEMISTRY* TOXICITY*BENTHIC COMMUNITY Analyte ERL ERM Result ERM-Q Percent Survival Index 2M-1 2R-1 3R-1 Mean St. Dev. Total METALS (mg/kg) Abundance 883 1214 219 772 507 2316 Antimony NA NA <1.74 NA Richness 11 18 20 16.3 4.73 29 Arsenic 8.2 70 3.21 0.05 Diversity 1.68 1.36 2.10 1.71 0.37 -- Cadmium 1.2 9.6 1.33 0.14 Evenness 0.70 0.47 0.70 0.62 0.17 -- Chromium 81 370 26.1 0.07 Dominance 3 2 5 3.3 1.53 -- Copper 34 270 16.5 0.06 Lead 46.7 218 7.65 0.04 Nickel 20.9 51.6 8.19 0.16 Selenium NA NA <1.74 NA Zinc 150 410 63.8 0.16 Mean ERM-Q 0.095 66% Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM values The mean ERM quotient for San Dieguito Lagoon, which is a measure of the cumulative effects of the COC for which ERMs are available, was 0.095. This was the third lowest mean ERM-Q of the embayments assessed and was less than the threshold of 0.10, which suggests a low probability of producing adverse biological effects (Long et al. 1998). During the 2003 ABLM program San Dieguito Lagoon had the fourth lowest mean ERM-Q (0.078). Toxicity. The percent survival of E. estuarius exposed to San Dieguito Lagoon sediments in a 10-day acute toxicity test was 66 % (Table 7-8), which was significantly different from that of the Control (99%). This suggests that San Dieguito Lagoon sediments were toxic to the test organisms. The source of toxicity was unknown. No toxicity was detected during the 2003 ABLM program. Benthic Community Structure. A total of 2316 organisms were collected from San Dieguito Lagoon, representing 29 taxa (Table 7-8). During the 2003 ABLM program a total of 161 organisms were collected, representing five taxa. Site 2R-1 had the greatest abundance of organisms in 2004, but taxa richness, diversity, evenness, and dominance were greatest at Site 3R-1. Based on these indices, the benthic community structure at San Dieguito Lagoon had a rank of 4 where 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. The polychaete, Capitella capitata, dominated the benthic community in the Lagoon, accounting for 42.5 % of all the animals collected (Table 7-9). This was the sixth most common taxon found in all of the embayments monitored in the ABLM Program. The mollusk, Tryonia imitator, comprised 26.1% of the animals collected, followed by the crustacean, Tethygenia opata, with 8.5% of the total. During the 2003 ABLM program the barley snail Barleeia sp, was the most dominant species and accounted for 87.6% of all animals collected. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-16 Table 7-9. Dominant infaunal species found in the San Dieguito Lagoon during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition SDL Capitella capitata Polychaeta 986 42.5 Tryonia imitator Mollusca 606 26.1 Tethygenia opata Crustacean 198 8.5 * Values were calculated from the total of all sites assessed. Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for San Dieguito Lagoon were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). The results are presented in Figure 7-5. For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. For San Dieguito Lagoon, the relative ranks were 3 for chemistry, 10 for toxicity, and 4 for benthic community structure.. 7.4.1.3 Summary and Conclusions Sediments in San Dieguito Lagoon were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size). Two sites were located in the middle stratum (2M-1, 2R-1), which is a side channel of the Lagoon. The third site (3R-1) was located in the inner stratum. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven metals were found in the Lagoon sediments. Cadmium exceeded its ERL value slightly but none exceeded its respective ERM value. The mean ERM- Q for San Dieguito Lagoon was low, which suggests a low potential for toxicity. There were no PAHs, PCBs, or pesticides found above the detection limit in San Dieguito Lagoon. In contrast, percent survival of test organisms exposed to San Dieguito Lagoon sediments was significantly different from that of the Control, indicating a possibility of toxicity associated with the sediments. The relative ranks for San Dieguito Lagoon compared to other embayments in the ABLM Program were 3 for chemistry, 10 for toxicity, and 4 for benthic community structure. Compared to the other embayments in the 2004 ABLM program, San Dieguito Lagoon had an overall rank of five. During the 2003 ABLM program the Lagoon had an overall rank of four. An increase in overall ranking indicates a decrease in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 0 2 4 6 8 10 12 Chemistry Toxicity Benthos RankingFigure 7-5. Relative rankings for sediment in San Dieguito Lagoon. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-17 7.5 WMA Assessment The San Dieguito River watershed management area was assessed utilizing chemistry and toxicity data collected during storm events from a mass loading station (MLS) located on San Dieguito River, chemistry data collected from three dry weather monitoring sites upstream of the MLS, and an Index of Biotic Integrity (IBI) score generated at two bioassessment sites. The watershed management area assessment methods presented in Section 3.4 were applied to these data in order to determine any constituents of concern (COC), as well as to develop a water quality objective (WQO) exceedance occurrence frequency for each of these constituents. Constituent WQO exceedances in wet and dry weather, as well as the IBI scores of the non-reference bioassessment sites in the watershed, are summarized in Table 7-10. Exceedance frequencies are shown as high (three diamond), medium (two diamond), low (one diamond), or zero. Data from the constituent exceedance table were evaluated for this watershed using the triad decision matrix, the results of which are presented in Table 7-11. Table 7-10. Constituent exceedances in the San Dieguito River WMA. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters pH 0 0 0 0 1 33 0 0 1 8 0 0 - - BOD 0 0 0 0 1 33 0 0 1 8 NA NA - - COD 0 0 0 0 1 33 1 33 2 17 NA NA - - Total Dissolved Solids 3 100 3 100 3 100 3 100 12 100 NA NA ♦♦♦ 1 Total Suspended Solids 0 0 0 0 1 33 0 0 1 8 NA NA - - Turbidity 0 0 0 0 2 67 0 0 2 17 1 33 ♦ 8 Bacteriological Total Coliform 0 0 1 33 1 33 1 33 3 25 1 33 ♦ 8 Fecal Coliform 0 0 2 67 2 67 2 67 6 50 0 0 ♦♦ 5 Enterococcus 0 0 1 33 1 33 1 33 3 25 0 0 ♦ 9 Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 7-day reproduction 2 67 2 67 0 0 1 33 5 42 NA NA No Selenastrum 96-hour 2 67 0 0 1 33 0 0 3 25 NA NA No Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? Green Valley Creek NA Very Poor Very Poor Very Poor Very Poor NA San Dieguito River (DS) NA Poor Poor Poor Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-18 Several constituents were found to exceed their water quality objectives in the San Dieguito River watershed management area. One constituent had a high frequency of occurrence and was assigned three diamonds based on Criterion No. 1. This constituent was: • Total dissolved solids One constituent was identified as having a medium frequency of occurrence and received two diamonds based on Criterion No. 5. This constituent was: • Fecal Coliform The ranking for fecal coliform increased compared to the one diamond exceedance frequency of the 2003-2004 monitoring season. Three constituents had a low frequency of occurrence and were given one diamond. These constituents include: • Turbidity, • Total Coliform • Enterococcus Turbidity and total coliform each received one diamond based on Criterion No. 8 due to dry weather sampling exceedances. Enterococcus received one diamond, and although it had no dry weather exceedances, it had MLS exceedances between 25 and 50% and one exceedance from each of the last two years. None of these low frequency of occurrence constituents were ranked during the 2003-2004 monitoring season. Several other constituents have been identified as concerns because they are listed on the SWRCB 303(d) List. The following constituents are on the 303(d) list in the San Dieguito River WMA: • Bacteria Indicators • Sulfates • Color • Nitrogen • Phosphorus • TDS Toxicity tests conducted on Ceriodaphnia and Selenastrum since 2001 have indicated some evidence of toxicity. Higher toxicity occurred in the first two monitoring years (2001-2002 and 2002-2003) than in more recent years. Persistent toxicity is evident when more than 50% of the toxicity tests conducted on any species have a NOEC of less than 100%. Cumulatively, toxicity has not occurred in 50% or more of the tests, therefore there is no evidence of persistent toxicity associated with wet weather runoff in the San Dieguito River watershed. Cumulative IBI ratings for this WMA were poor at San Dieguito River and very poor at Green Valley Creek. These results suggest evidence of benthic alteration within the San Dieguito River watershed. Figure 7-6 summarizes the average number of water quality exceedances (including constituents that had no exceedances) for six categories of constituents and displays how water quality concerns are changing over time. This stacked bar chart groups constituents as either conventionals, nutrients, bacteria, pesticides, metals, or toxicity. It uses the number of MLS exceedances from values in Table 7-10. The overall frequency of exceedances of the water quality objectives at the San Dieguito River MLS has San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-19 remained low during the last four monitoring seasons. Only three constituent of concern groups emerged from the 2004-2005 sampling season, including bacteriological and conventional parameters and toxicity. San Dieguito Creek Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 7-6. Stacked bar chart of the number of wet weather exceedances of constituent groups in San Dieguito River. Triad Decision Matrix The triad decision matrix combines the occurrence of COC with the toxicity and bioassessment results to draw potential conclusions about the watershed and provide possible actions for future monitoring or assessment. Table 7-11 summarizes the results and lists possible conclusions and actions. Table 7-11. Decision matrix results for San Dieguito River WMA. Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions No persistent exceedances No persistent evidence of toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) No action necessary based on toxic chemicals. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. San Dieguito River Watershed San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-20 Total dissolved solids was the only constituent that was identified as having a high frequency of occurrence. However, TDS is not considered in the triad decision making process since the water quality objectives for this parameter as defined in the Basin Plan are established for municipal drinking water and do not necessarily reflect impacts on the ecology of the watersheds (See Section 3.4 for more complete details). Therefore, based on the triad decision matrix, there was no evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and indications of benthic alteration. The recommended actions within this watershed are to continue to monitor for all elements of the program to gather additional data for assessment and long-term trend analysis, consider evaluating different test organisms and to investigate the role of physical habitat disturbance. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the San Dieguito River WMA The water quality priority ratings presented in Table 7-12 are based on the methodology presented in the BLTEA report (WESTON, MOE, & LWA 2005) and are presented in the Methods Section 3.4. Constituent groups and stressor groups are given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicate that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on current results presented in this 2004-2005 annual report and data from the following programs: • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Co-permittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303d Listing Table 7-12. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the San Dieguito River WMA Priority Ratings* Constituent Groups Stressor Groups Watersheds/ Sub-watersheds Percentage of Total Area Heavy Metals Organics Oil and Grease Sediments Pesticides Nutrients Gross Pollutants Bacteria/ Pathogens Benthic Alterations Toxicity San Dieguito River WMA 100% C D D A D C B B B B Solana Beach HA (905.10) 13% C D D A D D A A A B Hodges HA (905.20) 14% D D D A C A A B B B San Pasqual HA (905.30) 20% D D D A C A A C B B Santa Maria Valley HA (905.40) 17% D D D B D C D A B B Santa Ysabel HA (905.50) 36% C D D B D D C B B B Notes: * = Rating Calculated Based on Area Weighted Averages of Score Value from the sub-watershed areas. ** = Priority Level (Highest-A to Lowest-D) San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-21 The purpose of the BLTEA ratings is to identify water quality priorities within a watershed based on weighted averages of the sub-watershed ratings. Because it is a weighted average, larger sub-watersheds will have a greater influence in the overall watershed rating. Sediment was the highest priority (A rated) constituent for the San Dieguito River WMA followed by gross pollutants, bacteria, benthic alteration, and toxicity which were given a B rating. All other constituents were given either a C or D rating. The Solana Beach sub-watershed which accounts for 13% of the San Dieguito River WMA, had high priority (A) ratings for sediments, gross pollutants, bacteria and benthic alteration. The Hodges sub- watershed which accounts for 14% of the San Dieguito River WMA, had high priority (A) ratings for sediments, nutrients, and gross pollutants. The San Pasqual sub-watershed which accounts for 20% of the San Dieguito River WMA, had high priority (A) ratings for sediments, nutrients, and gross pollutants. The Santa Maria Valley sub-watershed which accounts for 17% of the San Dieguito River WMA, only bacteria was given a high priority (A) rating. The Santa Ysabel sub-watershed which accounts for 36% of the San Dieguito River WMA, did not have any high priority (A) ratings for any constituent group. All of the sub-watersheds were given B ratings for toxicity and benthic alteration, with the exception of the Solana Beach sub-watershed which received a high priority (A) rating for benthic alteration. A regional evaluation and description of the BLTEA is presented in the Regional Assessment Section 13. The complete tables used to calculate the ratings are presented in Appendix G. 7.6 Conclusions and Recommendations The San Dieguito River MLS run-off area accounts for only 8% of the overall San Dieguito WMA. Approximately 86% of the watershed lies behind dams (Coastal Conservancy 2001). The major land uses within the contributing runoff area are undeveloped (24%), parks (24%), residential (21%), and agricultural (18%). For the San Dieguito River, only TDS was identified as a high frequency of occurrence COC, fecal coliform was identified as a medium frequency of occurrence COC, and turbidity, total coliform, and enterococcus were identified as low frequency of occurrence COC. The in-stream benthic community appears to be limited by unknown factors, and while high TDS levels may be affecting diversity, there may be other constituents not measured that are impacting the benthic community. In San Dieguito Lagoon, the relative rankings were 3 for chemistry, 10 for toxicity, and 4 for benthic community structure. Overall, the San Dieguito Lagoon was rated intermediate compared to other embayments within San Diego County. The San Dieguito Lagoon experienced a decrease in relative quality compared to the 2003 ABLM program. In addition to the WMA assessment findings, the LTEA ratings found sediments as a high priority (A) rating followed by gross pollutants, bacteria, benthic alteration, and toxicity which were given a B rating. The information provided from the triad matrix results used in conjunction with the LTEA ratings can assist the jurisdictions in making informed decisions in developing their WURMP programs. The two reports also allow for an evaluation of where data gaps exist and where efforts should be targeted. San Dieguito River WMA SECTION 7 2004-2005 Urban Runoff Monitoring Report 7-22 Utilizing the BLTEA rating methods for future data evaluations would also allow for long-term BMP effectiveness assessment. Incorporation of additional useable data from other third party sources such as POTWs and non-profit organizations would also help to increase the confidence of the BLTEA ratings and overall WMA assessments. The recommendations for the San Dieguito River watershed are to continue monitoring to gather additional data for assessment and long-term trend analysis and to investigate the role of physical habitat disturbance. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-1 8.0 LOS PEÑASQUITOS CREEK WATERSHED MANAGEMENT AREA 8.1 Monitoring Site Descriptions The Los Peñasquitos watershed management area includes two hydrologic areas: Miramar Reservoir (HA 906.10) and Poway (HA 906.20). Los Peñasquitos Lagoon lies at the mouth of Los Peñasquitos Creek and is part of the northern border of the City of San Diego. The Los Peñasquitos watershed management area covers an area of over 60,400 acres and its major population center is the City of Poway to the east (Figure 8-1). The majority of the watershed management area is highly urbanized and is located mainly west of Interstate 15. The largest area of the Los Peñasquitos watershed management area lies within the City of San Diego, with other areas located within Del Mar, Poway, and unincorporated areas of San Diego County. Land use within the watershed management area is primarily parks (29%), residential (25%) and undeveloped (20%) with a total population of over 232,000 in 2002. This watershed management area supports a variety of ecosystems and provides many beneficial uses (Table 8-1). Major impacts to the Los Peñasquitos watershed management area include surface water quality degradation, beach closures, sedimentation, habitat degradation and loss, invasive species, and eutrophication (San Diego County 2002). Three water bodies within the watershed management area have been placed on the SWRCB 2002 303(d) list for sedimentation and bacterial indicators, respectively (Table 8-2). Urban runoff, sewage spills, and reduced tidal flushing are factors that may be impairing water quality within the Los Peñasquitos watershed management area. In addition, restricted or intermittent tidal flushing as a result of sediment accumulation at the mouth of the Los Peñasquitos Lagoon limits the transfer of pollutants to the Pacific Ocean. Table 8-1. Beneficial uses within the Los Peñasquitos watershed. Beneficial Uses Inland Surface Waters Coastal Waters Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z z Agricultural Supply z z Industrial Service Supply z z z Industrial Process Supply Hydropower Generation z Navigation Contact Water Recreation z z1 z1 Non-Contact Water Recreation z z z Commercial and Sport Fishing Warm Freshwater Habitat z z Cold Freshwater Habitat z Biological Habitats of Special Significance z Estuarine Habitat z Wildlife Habitat z z z Rare, Threatened, or Endangered Species z z Marine Habitat z Migration of Aquatic Organisms z Shellfish Harvesting z Aquaculture Spawning, Reproduction and/or Early Development 1 Shore and boat fishing only. Other REC1 uses prohibited. Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-2 Figure 8-1. Los Peñasquitos Watershed Management Area. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-3 Table 8-2. Water bodies on the SWRCB 303(d) list in the Los Peñasquitos watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor Los Peñasquitos Lagoon Miramar Reservoir 906.10 Sediment/Siltation Pacific Ocean Shoreline Miramar Reservoir 906.10 Bacteria Indicators Source: SWRCB 2003 Annual rainfall over the watershed management area ranges from 10.5 inches near the coast to 16.5 inches over the eastern portion of the watershed (Figure 8-1). The Los Peñasquitos Creek (PC) mass loading station is located in San Diego, at the North end of Sorrento Valley Court, under the Sorrento Valley Court Bridge. This Creek has an earthen bottom, and rip-rap along the sides of the channel. The contributing runoff area consists of over 36,700 acres and comprises approximately 60% of the Los Peñasquitos watershed management area. The major land uses within the contributing runoff area are parks (29%), residential (28%), and undeveloped (24%). Stream bioassessment in the Los Peñasquitos WMA has been performed at three urban affected sites. The farthest upstream site is in the City of Poway at Cobblestone Creek Road. The instream habitat at this site is dominated by large stable cobblestone with a riparian zone that is only lightly impacted by low density housing. Another site has been monitored that is downstream of the Black Mountain Road crossing in the Los Peñasquitos Canyon Preserve. This monitoring reach has a fairly low gradient and although the stream bed and riparian zone are unimpaired, the in-stream substrate is dominated by compacted clay and lacks stable rocky substrate. For this reason, upstream monitoring is now focused on the Cobblestone Creek Road site. The downstream site is located along Sorrento Valley Road near the Interstate 805 exit. The habitat quality is fairly good, with thick riparian vegetation and a cobble dominated substrate. The cobble, however, is generally small and unconsolidated, and substantial disruption occurs during periods of high flow. At the upper end of the reach, some large stable rip rap is present, and sampling has incorporated this to complement the unstable portions of the reach. Los Peñasquitos Creek flows into Los Peñasquitos Lagoon. The Lagoon is located at the northwestern border of the City of San Diego within the Torrey Pines State Reserve. There are approximately 630 acres of wetland habitat in the Lagoon system, but only 30 acres that are classified as open water (Coastal Conservancy 2000). Most of the open water habitat lies within two main arms of the Lagoon situated between Torrey Pines Road (Highway 1) and Carmel Valley Road. The arms are interconnected by a series of narrow, sinuous channels. All three of the Ambient Bay and Lagoon monitoring sites were located within the northern arm (Figure 8-1). The main source of fresh water to Los Peñasquitos Lagoon is Los Peñasquitos Creek and Carmel Creek. In addition, eight storm drains empty directly to the Lagoon. The ocean inlet to the Lagoon is located on Torrey Pines State Beach. Tidal influence is restricted by the Highway 1 crossing and without mechanical clearing would be blocked with sediment for extended periods. Historically, treated sewage was discharged to the Lagoon from 1962 to 1972. Currently, the Lagoon is crossed by sewage pipelines, but the adjacent land use is primarily residential and open space. Los Peñasquitos Lagoon is listed on the SWRCB’s 2002 303(d) list for sediment/siltation (Table 8-2). Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-4 8.2 Storm Water Monitoring Summary 8.2.1 2004-2005 Results The Los Peñasquitos Creek mass loading station was monitored for the fourth consecutive year for a total of 12 storms since 2001. For the 2004-2005 wet season events, monitoring took place on October 17, 2004 and February 11 and 18, 2005. The results for all 12 storms were compared to water quality objectives to identify potential water quality concerns during storm flow (Table 8-3). During the October 17, 2004 storm event, fecal coliform, chemical oxygen demand (COD) and TDS exceeded the water quality objectives (Table 8-3). The values for COD and TDS were much higher during this storm event than the majority of the other events monitored since 2001. High TDS during storm events is common at this and other sites that are monitored throughout San Diego County and has exceeded the water quality objective in every storm monitored since 2001. Fecal coliform densities exceeded WQO during all storm events in 2004-2005. During the October 17, 2004 storm, there were exceedances in total suspended solids and turbidity, both of which were much higher than previously monitored storm events. None of the objectives for pesticides, hardness, total metals, and dissolved metals were exceeded in the 2004-2005 season at the Los Peñasquitos Creek mass loading station. None of the samples from Los Peñasquitos Creek caused toxicity to any of the three test species during any of the storm events monitored in 2004-2005 (Table 8-3) (See Section 3.1.6.2 for details on toxicity testing). Table 8-3. Analytes measured at the Los Peñasquitos Creek mass loading station.11/29/01 2/17/02 3/17/02 11/8/02 12/16/02 2/11/03 11/12/03 2/3/04 2/18/04 10/17/04 2/11/05 2/18/05Electrical Conductivity umhos/cm 2640 2700 1590 1827 1939 26002470 3060 35403270 2690 1213Oil And Grease mg/L 15 USEPA Multi-Sector General Permit <1 1 <1 3.24 <1.00 1.39<1 <1 <1<1 <1 <1 0% 0.06pH pH Units 6.5-8.5 Basin Plan 7.7 7.8 7.5 7.46 7.63 7.786.91 7.83 8.297.76 7.48 6.85 0% 0.00Enterococci MPN/100 mL 500 1,700 3,000 230,000 500 22,000700 1,700 5001,112 3,000 8,000Fecal Coliform MPN/100 mL 400 Basin Plan 13050030030,000 500 1,700 1,300130 130500 500 2,20067% 7.89Total Coliform MPN/100 mL 1,700 3,000 500 500,000 1,400 50,0005,000 13,000 23017,000 13,000 50,000Ammonia As N mg/L 0.2 <0.1 <0.1 <0.1 <0.1 <0.1<0.1 <0.1 <0.1<0.1 0.14 <0.1Un-ionized Ammonia as Nμg/L25 (a) Basin Plan<0.84 <1.13 <1.350.11 0.73 2.020.9 0.3 0.1 0% 0.03Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit 3.1 5.6 21.3 5.55 <2.0 8.313.28 28.6 5.2823.7 3.75 2.31 0% 0.31Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit <25 50 54 73 53 11547 108 5614362 36 8% 0.56Dissolved Organic Carbon mg/L 16.8 11.0 11.214 6.41 77.227.2 4.44 4.66Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.9 <0.05 0.15 0.52 0.40 0.280.21 0.13 0.110.14 0.1 0.51 0% 0.14Nitrate As N mg/L 10 Basin Plan 0.2 0.3 0.3 1.32 0.98 0.600.28 0.11 <0.050.09 0.6 1.06 0% 0.05Nitrite As N mg/L 1 Basin Plan <0.05 <0.05 <0.05 0.11 <0.05 <0.05<0.05 <0.05 <0.05<0.05 <0.05 <0.05 0% 0.03Surfactants (MBAS) mg/L 0.5 Basin Plan <0.5 <0.5 <0.5 0.2 <0.1 <0.1<0.5 <0.5 <0.5<0.5 <0.5 <0.5 0% 0.43Total Dissolved Solids mg/L 500 Basin Plan by watershed1580 1590 1010 955 1280 997 1380 1890 20402120 1500 804100% 2.86Total Kjeldahl Nitrogen mg/L 1.7 1 1.2 1.9 0.8 1.21.2 2.5 2.11.6 1.9 0.8Total Organic Carbon mg/L 22.7 57.4 13.610.5 8.86 95.629.9 9.51 10.8Total Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.1 0.15 0.23 0.73 0.60 0.390.23 0.2 0.170.14 0.28 0.69 0% 0.16Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit <20 <20 <20 35 58 3827 <20 <20<20 <201088% 0.28Turbidity NTU 20 Basin Plan 3.8 3.33 5.05 17.145.4 29.97.53 8.98 2.747.89 9.0556.425% 0.82Chlorpyrifosμg/L 0.02 CA Dept. of Fish & Game <0.03* <0.03* <0.03*0.055 0.067<0.03*<0.01 <0.01 <0.01<0.01 <0.01 <0.01 17% 0.88Diazinonμg/L 0.08 CA Dept. of Fish & Game0.120.060.13 0.2310.040 0.077<0.01 <0.01 <0.01<0.01 <0.01 <0.01 25% 0.72Malathionμg/L 0.43 CA Dept. of Fish & Game <0.10 <0.10 <0.10<0.01 <0.01 <0.01<0.01 <0.01 <0.01 0% 0.05HardnessTotal Hardness mg CaCO3/L 808 815 551 428 602 602692 805 8801000 707 379Antimony mg/L 0.006 Basin Plan <0.002 <0.002 <0.002 <0.002 0.0050.009<0.005 <0.005 <0.006 <0.005 <0.005 <0.0058% 0.47Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan 0.002 0.002 0.003 0.012 0.005 0.003<0.002 0.006 0.005 0.005 0.004 <0.0020% 0.08Cadmium mg/L 0.0046 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.01Chromium mg/L 0.016 CTR (Cr VI) <0.005 <0.005 <0.005 0.008 0.006 <0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.00Copper mg/L 0.0135 40 CFR 131 <0.005 <0.005 0.008 0.021 0.004 0.010<0.005 0.008 0.006 <0.005 <0.005 <0.0050% 0.08Lead mg/L 0.082 40 CFR 131 <0.002 <0.002 0.003 0.011 0.004 0.003<0.002 <0.002 <0.002 <0.002 <0.002 0.002Nickel mg/L 0.47/0.1 40 CFR 131/ Basin Plan <0.002 <0.002 <0.002 0.026 <0.002 0.0020.003 <0.002 <0.002 0.003 0.002 0.0020% 0.00Selenium mg/L 0.02 40 CFR 131 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.10Zinc mg/L 0.122 40 CFR 131 <0.020 <0.020 0.020 0.058 0.006 <0.0200.028 <0.02 <0.02 <0.02 <0.02 <0.020% 0.03Antimony mg/L (e) 40 CFR 131 <0.002 <0.002 <0.002 <0.002 0.002 <0.002<0.005 <0.005 <0.006 <0.005 <0.005 <0.005Arsenic mg/L 0.34 (c) 40 CFR 131 0.002 <0.001 0.003 0.004 0.003 0.0030.002 0.004 0.004 <0.002 <0.002 <0.0020% 0.00Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 0.0002 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.01Chromium mg/L (b) 40 CFR 131 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.00Copper mg/L (b) 40 CFR 131 <0.005 <0.005 <0.005 0.007 <0.005 0.027<0.005 0.005 0.005 <0.005 <0.005 <0.0050% 0.07Lead mg/L (b) 40 CFR 131 <0.002 <0.002 <0.002 <0.002 0.002 <0.002<0.002 <0.002 <0.002 <0.002 <0.002 <0.002Nickel mg/L (b) 40 CFR 131 <0.002 0.003 <0.002 0.003 <0.002 0.0020.002 0.002 <0.002 0.003 0.002 0.0020% 0.00Selenium mg/L 0.02 (d) 40 CFR 131 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.10Zinc mg/L (b) 40 CFR 131 <0.020 <0.020 <0.020 <0.020 0.020 0.106<0.02 <0.02 <0.02 <0.02 <0.02 <0.020% 0.03Frequency Above WQOMean Ratio to WQO2004-05Wet ChemistryPesticidesTotal MetalsDissolved Metals2001-02 2002-03General / Physical / OrganicBacteriologicalANALYTE UNITS WQO SOURCE2003-04 Table 8-3. Analytes measured at the Los Peñasquitos Creek mass loading station.11/29/01 2/17/02 3/17/02 11/8/02 12/16/02 2/11/03 11/12/03 2/3/04 2/18/04 10/17/04 2/11/05 2/18/05Frequency Above WQOMean Ratio to WQO2004-052001-02 2002-03ANALYTE UNITS WQO SOURCE2003-04Ceriodaphnia 96-hr LC50 (%) 100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 0% 0.00Ceriodaphnia 7-day survival NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Ceriodaphnia 7-day reproduction NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Hyalella 96-hr NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Selenastrum 96-hr NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Sources(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000Blank spaces have been verified and no data is available due to changes in the monitoring program.ToxicityUSEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Table 3 - Parameter benchmark values.USEPA Federal Register Document 40 CFR Part 131, May 18, 2000.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.Shaded text – exceeds water quality objective.* Indicates detection limit exceeds water quality objective.(e) USEPA has not published an aquatic life criterion value.(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-7 8.2.2 Relationships/Analyses As with many other watersheds in San Diego County, high concentrations of total dissolved solids appear to characterize water quality in the Los Peñasquitos Creek watershed. The Basin Plan water quality objective for TDS (500 mg/L) has been exceeded for this WMA during all of the 12 storm events since 2001 with values ranging from 804 to 2,120 mg/L. Residential irrigation may be a major contribution to total dissolved solids through the importation of water high in dissolved solids and through the leaching of minerals from the soil. The water quality objective for fecal coliform bacteria was exceeded during 8 of the 12 (66%) storm events monitored since 2001. Other water quality concerns such as TSS, turbidity, Diazinon, and Chlorpyrifos have exceeded water quality objectives only sporadically in storm water runoff since 2001. However, there is a significant decreasing trend in Diazinon concentrations (R2=0.45). Toxicity testing has been performed on storm water for the past four years or 12 events (See Section 3.1.6.2 for details on toxicity testing). During that time, none of the storm water samples have been toxic to any of the test organisms. In order to illustrate the magnitude of the water quality exceedances for 2004-2005, the ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern. The results are shown in Figure 8-2. The largest single exceedance was for fecal coliform, which exceeded the WQO by 5.5 times during the February 18, 2005 storm. TDS also exceeded the WQO by 4.2 times during the October 17, 2004 storm event, by 3 times during the February 11, 2005 storm event and by 1.5 times during the February 18, 2004 storm. There was also a noticeable single exceedance for turbidity (2.8 times the WQO). The average magnitude of water quality exceedances was also determined for each constituent by calculating the mean ratio of water quality results to the WQOs from all storm events from October 2001 through April 2004. Mean ratios are illustrated in Figure 8-2. The largest average exceedance for the period of record was for fecal coliform (9.6 times the WQO) followed by TDS, which exceeded the WQO by 2.8 times. In addition to the wet weather monitoring discussed above, there are 22 sites in the Los Peñasquitos Creek WMA where water quality is monitored during dry weather. Of these, 14 are located upstream of the mass loading station on Los Peñasquitos Creek. The dry weather data for this site is useful, but it is important to remember that it represents only one year of monitoring. Most of the dry weather data were collected from concrete channels or outfalls (See Section 3.4 for details on dry weather sampling). Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-8 TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 Ratio to WQOMean Ratio (Oct 01 to Apr 04) 10/17/04 2/11/05 2/18/05 Above WQO Figure 8-2. Los Peñasquitos Creek water quality ratios. Table 8-4 shows exceedances and ratios of exceedances for constituents that were measured during the 2004 dry weather monitoring program. During dry weather sampling, there were exceedances of water quality criteria at the monitoring sites located above the mass loading station for turbidity, conductivity, ammonia, phosphorus, dissolved copper, total coliform, and enterococcus. Of these, turbidity and total coliform had ratios of exceedance greater than one. A map for the WMA showing DWS exceedances is found in Figure 8-3. Pie symbols appear at dry weather stations that have had water quality exceedances. The colored slices of the pie show the different constituent groups that contributed to the exceedances. The only COC that was common between the wet and dry weather monitoring program was turbidity. Table 8-4. Los Peñasquitos WMA 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* St. Dev. Ratio of Exceedance Turbidity 3 13 1.69 3.98 Conductivity 1 13 0.36 0.35 Ammonia 2 12 0.66 1.66 Phosphorus 2 13 0.58 0.62 Dissolved Copper 1 14 0.17 0.43 Total Coliform 4 14 2.27 4.70 Enterococcus 3 14 1.00 1.82 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-9 No toxicity has been found for any test at Los Peñasquitos Creek; therefore no significant relationships with COC were found in the chi-square test. 8.2.3 Third Party Data Third party data was collected from three locations in 2002 within Los Peñasquitos watershed under the Surface Water Ambient Monitoring Program (SWAMP) and was provided by the San Diego Regional Water Quality Control Board. Sampling sites were located on Los Peñasquitos Creek, Soledad Canyon Creek and Poway Creek. Grab samples were collected from each station during dry weather once in March, April, June and September, 2002 (12 total observations). Results are presented in Table H-2 in Appendix H. Data collected from Los Peñasquitos Creek were compared to the mass loading station and dry weather data results to provide qualitative assessments with current wet and dry weather results. The other two stations within the watershed were too spatially disconnected from the MLS to correlate the data with any of the wet and dry weather monitoring results, however, exceedances were noted. One station, 906LPLC6, was located on Los Peñasquitos Creek in the same vicinity as the mass loading station. There were water quality objective exceedances for turbidity, pH, sulfate, Diazinon, methyl parathion and toxicity. Sulfate concentrations exceeded objectives during three out of four sampling events, while turbidity, pH, Diazinon and methyl parathion each exceeded objectives during one event. Toxicity at Los Peñasquitos Creek was evident for Selenastrum growth during three events and Ceriodaphnia reproduction during one sampling event. All other constituents were below their respective water quality objectives. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedances were for turbidity during wet and dry weather and Diazinon during wet weather, however these exceedances were not persistent. Turbidity and Diazinon concentrations exceeded objectives during 3 out of 12 storm events, and during dry weather, turbidity exceeded objectives during 3 out of 13 events. Exceedances observed at the other two stations within Los Peñasquitos watershed were similar to exceedances that were found in Los Peñasquitos Creek. Sulfate, manganese and toxicity consistently exceeded objectives at all sites: manganese exceeded objectives during all sampling events at both stations; sulfate exceeded objectives in all but two events; and there was toxicity to at least one test organism during all sampling events at both stations. Turbidity and Diazinon concentrations only exceeded objectives during one sampling event at one station. 8.2.4 TIEs TIE testing was not performed on Los Peñasquitos Creek samples. This mass loading station has not been identified as a TIE candidate site based upon the Triad Decision Matrix. Toxicity was not observed in any of the three storm events in 2004-2005. 8.2.5 Summary and Conclusions Elevated levels of TDS during wet weather continues to be the primary water quality concern in the watershed. High levels of other constituents, particularly fecal coliform bacteria, occur occasionally and do not appear to be consistently problematic. There were 14 dry weather monitoring sites located upstream of the mass loading station. The data from these sites suggested that there were several constituents that exceeded the water quality objectives, but there was no clear link between dry and wet weather constituents. There has been no toxicity associated with storm water in any of the 12 storms assessed since 2001. Third party data collected in 2002 indicated that sulfate, manganese and toxicity were consistent problems throughout Los Peñasquitos watershed. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-10 Figure 8-3. Los Peñasquitos WMA dry weather exceedance map. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-11 8.3 Stream Bioassessment Stream bioassessment in the Los Peñasquitos WMA included two urban affected monitoring sites. The upstream site was in Los Peñasquitos Canyon Creek at Cobblestone Creek Road, on the downstream side of the city of Poway. The downstream site was in Carroll Canyon Creek near the Highway 805 overcrossing in Sorrento Valley. 8.3.1 Results and Discussion Los Peñasquitos Canyon Creek Monitoring Site: LPC-CCR The Los Peñasquitos Canyon Creek monitoring site had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Very Poor for both the October and May surveys (Table 8-5) (See Section 3.2 for details on the sampling approach). Taxa richness for the two surveys was moderate, with 20 and 14 unique taxa collected, with 3 and 2 EPT taxa in October and May, respectively. There were no organisms collected that are highly intolerant to impairment, and the occurrence of organisms highly tolerant was fairly low, comprising 12% and 3% of the community in October 2004 and May 2005, respectively. The physical habitat of the site was near optimal, with a substrate primarily of layered cobble, and there was a good oak and sycamore riparian zone. There was some development in close proximity to the monitoring reach, consisting of low density residential use. Specific conductance was fairly low, measuring 1.636 mS/cm in October and 0.962 mS/cm in May (Table 8-5). pH values were 7.4 and 7.6 for the October and May surveys, respectively. The benthic community was dominated by the mayflies, Fallceon quilleri and Baetis, and the black fly, Simulium (Table 8-6). The damselfly, Argia, made up 10% of the community in the October survey, following a typical San Diego seasonal pattern of increased predator taxa collected during fall surveys. The Los Peñasquitos Creek mass loading station was too spatially disconnected from the bioassessment site to correlate any of the storm water information with the benthic community. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-12 Table 8-5. Selected Biological Metrics and Physical Measures of the Los Peñasquitos WMA. Los Peñasquitos Watershed Management Area Los Peñasquitos Creek at Cobblestone Creek Road (LPC-CCR) Carroll Canyon Creek at Highway 805 (CCC-805) Survey Oct-04 May-05 Oct-04 May-05 Index of Biotic Integrity/ Qualitative Rating 12 Very Poor 9 Very Poor 18 Poor 9 Very Poor Metrics Taxa Richness 20 14 21 14 EPT Taxa (mayflies, stoneflies, and caddisflies) 3 2 2 3 % Intolerant Taxa 0% 0% 0% 0% % Tolerant Taxa 12% 3% 64% 2% Average Tolerance Value 5.4 5.8 7 5.6 % Collector Filterers +Collector Gatherers 85% 98% 53% 99% Physical Measures Elevation 440 80 Physical Habitat Score 160 158 119 126 Riffle Velocity (ft/sec) 2.7 2.1 1.6 2 Substrate Composition Silt 20% Sand 5% 2% 7% Gravel 22% 13% 10% 35% Cobble 68% 75% 70% 58% Boulder 5% 2% Bedrock/Solid 8% Water Quality Temperature ºC 15.1 18.3 23.7 18.5 pH 7.4 7.6 8.2 7.8 Specific Conductance (ms/cm) 1.636 0.962 3.738 2.263 Relative Chlorophyll (μg/L) 6.2 6.5 6.2 2.7 Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-13 Table 8-6. Los Peñasquitos WMA Community Summary. Taxon Common Name Percent Composition Tolerance Value Functional Feeding Group Fallceon quilleri minnow mayfly 34% 4 Collector Gatherer Oligochaeta earthworm 17% 5 Collector Gatherer Argia dancer damselfly 10% 7 Predator Baetis minnow mayfly 7% 5 Collector Gatherer Oct-04 Hyalella amphipod 7% 8 Collector Gatherer Simulium black fly 59% 6 Collector Filterer Baetis minnow mayfly 16% 5 Collector Gatherer Chironomidae non-biting midges 11% 6 Collector Gatherer/Filterer Oligochaeta earthworm 4% 5 Collector Gatherer Los Peñasquitos Creek at Cobblestone Creek Road (LPC-CCR) May-05 Hyalella amphipod 2% 8 Collector Gatherer Ostracoda seed shrimp 32% 8 Collector Gatherer Prostoma tongue worm 17% 8 Predator Turbellaria flatworm 17% 4 Predator Caloparyphus/ Euparyphus soldier fly 9% 8 Collecter Gatherer Oct-04 Sperchon mite 7% 5 Predator Baetis minnow mayfly 43% 5 Collector Gatherer Chironomidae non-biting midges 26% 6 Collector Gatherer/Filterer Simulium black fly 25% 6 Collector Filterer Fallceon quilleri minnow mayfly 2% 4 Collector Gatherer Carroll Canyon Creek at Highway 805 (CCC-805) May-05 Oligochaeta earthworm 1% 5 Collector Gatherer Carroll Canyon Creek Monitoring Site: CCC-805 The Carroll Canyon Creek monitoring site had a benthic macroinvertebrate community with Index of Biotic Integrity ratings of Poor and Very Poor in October 2004 and May 2005, respectively (Table 8-5). Taxa richness for the two surveys was 21 and 14, with 2 and 3 different EPT taxa collected in October 2004 and May 2005, respectively. There were no organisms collected that are highly intolerant to impairment, and the occurrence of organisms highly tolerant was variable, comprising 64% of the community in October, and 2% of the community in May. The physical habitat of the site was sub-optimal, with a substrate primarily of smooth layered cobble. The willow dominated riparian zone was disturbed in some portions of the reach due to the proximity of commercial development. Specific conductance was fairly high, measuring 3.738 ms/cm in October and 2.263 ms/cm in May. pH values were 8.2 and 7.8 in the October and May surveys, respectively. Field biologists noted in the October survey that the site had very heavy deposits of fine sediment. The benthic community was seasonally variable. In October the community was dominated by Ostracods, Nemerteans (tongue worms), and flatworms (Table 8-6). Also collected in October were two species of water scavenger beetle, Tropisternus and Uvarus. In May, the community was dominated by the mayfly, Baetis, Chironomid midges, and the black fly, Simulium. The Los Peñasquitos Creek mass loading station was located approximately one mile away from the bioassessment station on Carroll Canyon Creek, and water quality measures from storm water may have Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-14 contained constituents that were not present in the bioassessment site. The ubiquity of total dissolved solids in all of the storm water samples in the region may imply that this was also a constituent of concern at the bioassessment site. Pesticides, metals, and toxicity to Ceriodaphnia and Hyalella from storm water were generally undetectable at the MLS. 8.3.2 Summary and Conclusions The Los Peñasquitos WMA was sampled at two sites. The upstream site was in Los Peñasquitos Creek in Poway, and the downstream site was in Carroll Canyon Creek in Sorrento Valley. Both of the sites had Index of Biotic Integrity ratings that were in the upper range of Very Poor or lower Poor categories. The Carroll Canyon Creek site was rated slightly higher than the upstream site on Los Peñasquitos Creek, possibly due to different watershed areas contributing to the different streams. 8.4 Ambient Bay and Lagoon Monitoring 8.4.1 Results and Discussion 8.4.1.1 Phase I Results and Discussion Sediment samples were collected in Los Peñasquitos Lagoon for the ABLM Program on June 3, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 8-4. The median grain size at Los Peñasquitos Lagoon ranged from 5 μm at Sites 2L-4 and 2R-1 in the middle Lagoon, to 138 μm at Site 1L-1 in the outer Lagoon (Table 8-7). The grain size characteristics of the sediments in the three outer Lagoon sites (Sites 1L-1, 1M-1 and 1R-2) were distinctly different from those at the other sites in the Lagoon. Sites in the outer Lagoon were composed primarily of sand (91.5% to 94.0%) and had a much smaller proportion of fine grained sediments than the other sites. These three sites also had a much lower TOC content (0.19% to 0.24%) compared to the other sites in the Lagoon (1.51% to 2.41%). The areas in Los Peñasquitos Lagoon with the highest proportion of fine grained sediments and high TOC content were found at Site 2R-1 in the middle stratum and Sites 3R-2 and 3M-2 in the inner stratum (Table 8-7). These sites were thus selected for Phase II assessment. Figure 8-4. Map of Phase I site locations in Los Peñasquitos Lagoon. Sites with yellow triangles were selected for Phase II assessment. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-15 Table 8-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Los Peñasquitos Lagoon. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II LPL-1L-1 0.10 94.0 2.90 2.97 138 139 5.88 0.19 1 2 3 LPL-1M-1 0.00 92.2 4.27 3.49 132 130 7.75 0.17 2 1 3 LPL-1R-2 0.00 91.5 4.49 3.97 116 112 8.46 0.24 3 3 6 LPL-2L-4 6.77 15.5 30.06 47.72 5 NC 77.78 1.51 5 4 9 LPL-2M-2 0.41 19.7 34.6 45.3 7.1 NC 79.86 1.52 6 5 11 LPL-2R-1 3.32 8.4 39.9 48.4 5 NC 88.33 2.41 9 9 18 * Yes LPL-3L-1 15.57 11.9 32.1 40.4 8.29 18.04 72.52 1.90 4 8 12 LPL-3M-2 1.40 17.8 34.3 46.5 5.3 4.69 80.77 1.72 8 6 14 * Yes LPL-3R-2 0.32 19.5 34.5 45.7 5.7 NC 80.22 1.84 7 7 14 * Yes Mean of all Sites 3.10 41.17 24.12 31.61 46.93 80.76 55.73 1.28 St. Dev. 5.19 38.72 15.41 21.22 61.57 64.25 36.51 0.85 NC = Not calculable (%silt + %clay > 84%) 8.4.1.2 Phase II Results and Discussion The three sites selected in Los Peñasquitos Lagoon as part of Phase I were sampled in Phase II on July 16, 2004. Sediments from Sites 2R-1, 3M-2 and 3R-2 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 8-8. Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, seven metals were detected above the detection limit in Los Peñasquitos Lagoon: arsenic, chromium, copper, lead, nickel, selenium and zinc (Table 8-8). This suite of metals, with the exception of selenium, was also found in all the other embayments assessed in the ABLM Program. Concentrations of metals were low in Los Peñasquitos Lagoon and none exceeded their respective ERM values. However, the concentration of arsenic exceeded the ERL value. With the exception of selenium, the same metals were detected above the detection limit during the 2003 ABLM program. All metal concentrations were low and did not exceed the ERM value during 2003, however copper and zinc did exceed their respective ERLs. There were no PAHs, PCBs, or pesticides found above the detection limit in Los Peñasquitos Lagoon during the 2004 program. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was 0.111. This value exceeded the threshold of 0.10. Sediments with mean ERM-Q values above this threshold have a higher probability of producing adverse biological effects than those with mean ERM-Qs below the threshold (Long et al. 1998). This is similar to the 2003 results where the mean ERM quotient was 0.109. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-16 Table 8-8. Summary of chemistry, toxicity, and benthic community structure in Los Peñasquitos Lagoon. CHEMISTRY* TOXICITY* BENTHIC COMMUNITY Analyte ERL ERM Result ERM- Q Percent Survival Index 2R-1 3M-2 3R-2 Mean St. Dev. Total METALS (mg/kg) Abundance 1171 614 648 811 312 2433 Antimony NA NA <1.74 NA Richness 32 31 25 29.3 3.79 49 Arsenic 8.2 70 9.39 0.134 Diversity 1.19 2.27 1.29 1.58 .060 -- Cadmium 1.2 9.6 <0.174 NA Evenness 0.34 0.66 0.40 0.47 0.17 -- Chromium 81 370 21.8 0.059 Dominance 2 5 2 3 1.73 -- Copper 34 270 14.4 0.053 Lead 46.7 218 17.7 0.081 Nickel 20.9 51.6 8.1 0.157 Selenium NA NA 1.98 NA Zinc 150 410 75.6 0.184 Mean ERM-Q 0.111 95.8% Not Significantly Different from control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value Toxicity. The percent survival of E. estuarius exposed to Los Peñasquitos Lagoon sediments in a 10-day acute toxicity test was 95.8% (Table 8-8). Percent survival was not significantly different from that of the Control (99%), suggesting that Los Peñasquitos Lagoon sediments were not significantly toxic to the test organisms. During the 2003 ABLM program toxicity was observed, but the source of toxicity was unknown. Benthic Community Structure. A total of 2433 organisms were collected from Los Peñasquitos Lagoon, representing 49 taxa (Table 8-8). During the 2003 ABLM program a total of 547 organisms were collected, representing 13 taxa. Total taxa abundance and richness were relatively high, fourth only to Mission Bay, Oceanside Harbor and Sweetwater. Site 2R-1 in the middle stratum had greater abundance and taxa richness than the inner stratum sites 3M-2 and 3R-2. However, diversity, evenness, and dominance were greatest at Site 3M-2, near the inner portion of the lagoon. Based on these indices, the benthic community structure in Los Peñasquitos Lagoon had a rank of 6, where 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. The crustacean, Grandidierella japonica, dominated the benthic community in the Los Peñasquitos Lagoon, accounting for 43.7% of all the animals collected (Table 8-9). This was the most common taxon found in all of the embayments monitored in the ABLM Program. The second most abundant species were the Phoronids, which accounted for 29.6% of the benthic community. Classified as minor Phyla, members of this phyla can form immense beds with as many as 1,200 individuals per m². The barley snail, Barleeia sp., was the third most abundant, accounting for 6.7% of the total abundance, which differs from the 2003 ABLM program where Barleeia sp. dominated the benthic community accounting for 52.1% of all animals collected. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-17 Table 8-9. Dominant infaunal species found in the Los Peñasquitos Lagoon during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Grandidierella japonica Crustacean 1063 43.7 Phoronida Minor phyla 721 29.6 LPL Barleeia sp Mollusca 755 6.7 * Values were calculated from the total of all sites assessed. Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Los Peñasquitos Lagoon were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 8-5. For Los Peñasquitos Lagoon, the relative ranks were four for chemistry, three for toxicity, and six for benthic community structure. 8.4.1.3 Summary and Conclusions Sediments in Los Peñasquitos Lagoon were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size): Site 2R-1 in the middle stratum and sites 3M-2 and 3R-2 in the inner stratum. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven of the nine metals assessed were found in Los Peñasquitos sediments. The mean ERM-Q for Los Peñasquitos Lagoon was 0.111, which was slightly above the published threshold value of 0.10 and therefore suggests the potential for increased toxicity. No ERMs were exceeded. There were no PAHs, PCBs, or pesticides found above the detection limit in Los Peñasquitos Lagoon during the 2004 program. The percent survival of test organisms exposed to Los Peñasquitos Lagoon sediments was the fourth highest (i.e., lowest toxicity) of any of the embayments assessed and not significantly different from that of the Control. The benthic community indices suggested that the biotic community in the Los Peñasquitos Lagoon had a rank of six, therefore intermediate compared to other embayments in the ABLM Program. The infaunal community was dominated by the crustacean, Grandidierella japonica, followed by members of the Phoronida phyla and the barley snail, Barleeia sp. The relative ranks for the Los Peñasquitos Lagoon compared to the other embayments of the ABLM Program were four for chemistry, three for toxicity, and six for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Los Peñasquitos Lagoon had an overall rank of two. During the 2003 ABLM program the Lagoon had an overall rank of six. A decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. Relative rankings for sediment in Los Penasquitos Lagoon 0 1 2 3 4 5 6 7 Chemistry Toxicity Benthos RankingFigure 8-5. Relative rankings for sediment in the Los Peñasquitos Lagoon. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-18 8.5 WMA Assessment The Los Peñasquitos watershed management area was assessed using data from both dry and wet weather monitoring efforts. One mass loading station located on Los Peñasquitos Creek collected chemistry and toxicity data during storm events. Chemistry data was collected from 14 dry weather monitoring sites upstream of the MLS. Two bioassessment sites were assessed and given an Index of Biotic Integrity score. The watershed management area assessment methods presented in Section 3.4 were applied to these data in order to determine any constituents of concern (COC), as well as to develop a water quality objective (WQO) exceedance frequency for each of these constituents. Constituent WQO exceedances in wet and dry weather, as well as the IBI scores of the bioassessment sites in the watershed, are summarized in Table 8-10. Using the evaluation criteria discussed in Section 3.4, constituents were assigned zero (no frequency), one (low frequency), two (medium frequency), or three diamonds (high frequency). Data from the constituent exceedance table were evaluated for this watershed using the triad decision matrix, the results of which are presented in Table 8-11. Several constituents exceeded their water quality objectives in the Los Peñasquitos watershed management area, including bacteria, nutrients, and conventionals. One constituent was identified as having a high frequency of occurrence and was assigned three diamonds based on Criterion No. 1(MLS results exceeded WQO in 100% of the samples). This constituent includes: • Total dissolved solids One constituent had a medium frequency of occurrence and received two diamonds based on Criterion No. 5. This constituent includes: • Fecal Coliform Five constituents were identified as having a low frequency of occurrence and are listed below. All constituents were assigned one diamond based on Criterion No. 8. • Turbidity • Total Coliform • Enterococcus • Ammonia • Orthophosphate In addition to TDS, which had a high frequency of occurrence in the Los Peñasquitos Watershed based on the triad decision matrix above, several other constituents have been identified as concerns because they are listed on the SWRCB 303(d) List. These include indicator bacteria associated with the Pacific Ocean shoreline and sediment and siltation associated with Los Peñasquitos Lagoon. There is no evidence of persistent toxicity associated with wet weather runoff at the Los Peñasquitos Creek MLS. Toxicity tests conducted on Ceriodaphnia, Hyalella and Selenastrum since 2001 have not shown a single incidence of toxicity. The IBI rating was very poor at the Cobblestone Creek site throughout the monitoring period. The Sorrento Valley Rd. site was rated as very poor during 2001-2002 and poor during 2002-2003, 2003- 2004, and 2004-2005. These scores suggest evidence of benthic alteration within Los Peñasquitos Creek watershed. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-19 Table 8-10. Constituent exceedances in the Los Peñasquitos WMA. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters COD 0 0 0 0 0 0 1 33 1 8 NA NA - - Total Dissolved Solids 3 100 3 100 3 100 3 100 12 100 NA NA ♦♦♦ 1 Total Suspended Solids 0 0 0 0 0 0 1 33 1 8 NA NA - - Turbidity 0 0 2 67 0 0 1 33 3 25 3 23 ♦ 8 Nutrients Ammonia 0 0 0 0 0 0 0 0 0 0 2 17 ♦ 8 Orthophosphate NA NA NA NA NA NA NA NA NA NA 2 15 ♦ 8 Bacteriological Total Coliform 0 0 2 67 0 0 1 33 3 25 4 29 ♦ 8 Fecal Coliform 1 33 3 100 1 33 3 100 8 67 0 0 ♦♦ 5 Enterococcus 0 0 2 67 0 0 0 0 2 17 3 21 ♦ 8 Pesticides Chlorpyrifos 0 0 2 67 0 0 0 0 2 17 0 0 - - Diazinon 2 67 1 33 0 0 0 0 3 25 0 0 - - Total Metals Antimony 0 0 1 33 0 0 0 0 1 8 NA NA - - Dissolved Metals Copper 0 0 0 0 0 0 0 0 0 0 1 7 - - Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? Los Peñasquitos Creek, at Cobblestone Creek Rd. Very Poor Very Poor Very Poor Very Poor Very Poor NA Los Peñasquitos Creek, at Sorrento Valley Rd. (DS) Very Poor Poor Poor Poor Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS Table 8-11. Decision matrix results for the Los Peñasquitos WMA. Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions No persistent exceedances No persistent evidence of toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) No action necessary based on toxic chemicals. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-20 Figure 8-6 summarizes the number of MLS water quality exceedances for six categories of constituents and displays how water quality concerns are changing over time. Categories include conventionals, nutrients, bacteria, pesticides, metals, and toxicity. The average exceedance frequency (including constituents that had no exceedances) was computed from values in Table 8-10 for each constituent category. The overall frequency of exceedances of the WQOs at the Los Peñasquitos Creek MLS has remained low during the last four monitoring seasons. Only two COC groups emerged from the 2004-2005 sampling season, including bacteriological and conventional parameters. Los Penasquitos Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 8-6. Stacked bar chart of the number of wet weather exceedances of constituent groups in Los Peñasquitos Creek. Triad Decision Matrix The triad decision matrix combines the occurrence of COC with the toxicity and bioassessment results to draw potential conclusions about the watershed and provide possible actions for future monitoring or assessment. Table 8-11 summarizes the results and lists possible conclusions and actions. Only total dissolved solids was identified as having a high frequency of occurrence. However, TDS is not considered in the triad decision making process since the water quality objectives for this parameter as defined in the Basin Plan are established for municipal drinking water and do not necessarily reflect Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-21 impacts on the ecology of the watersheds (See Section 3.4 for more complete details). Therefore, based on the triad decision matrix, there was no evidence of persistent water quality objective exceedances, no evidence of persistent toxicity, and indications of benthic alteration. Therefore, the recommended actions within this watershed are to continue monitoring to gather long- term trend information, consider evaluating different test organisms and to investigate the potential role of physical habitat disturbance. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Los Peñasquitos WMA The water quality priority ratings presented in Table 8-12 are based on the methodology presented in BLTEA report (WESTON, MOE, & LWA 2005) and are presented in the Methods Section 3.4. Constituent groups and stressor groups are given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicate that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on current results presented in this 2004-2005 annual report and data from the following programs: • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Co-permittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303d Listing Table 8-12. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Los Peñasquitos WMA Priority Ratings* Constituent Groups Stressor Groups Watersheds/ Sub-watersheds Percentage of Total Area Heavy Metals Organics Oil and Grease Sediments Pesticides Nutrients Gross Pollutants Bacteria/ Pathogens Benthic Alterations Toxicity Los Peñasquitos WMA 100% C D D A C D D A B D Miramar Reservoir HA (906.10) 55% C D D A C C D A B D Poway HA (906.20) 45% C D C B C D D B C D Notes: * = Rating Calculated Based on Area Weighted Averages of Score Value from the sub-watershed areas. ** = Priority Level (Highest-A to Lowest-D) The purpose of the BLTEA ratings is to identify water quality priorities within a watershed based on weighted averages of the sub-watershed ratings. Because it is a weighted average, larger sub-watersheds will have a greater influence in the overall watershed rating. Los Peñasquitos Creek WMA SECTION 8 2004-2005 Urban Runoff Monitoring Report 8-22 Sediments and bacteria were the highest priority (A rated) constituents for the Los Peñasquitos WMA followed by benthic alteration which was given a B rating. All other constituents were given either a C or D rating. The Miramar Reservoir sub-watershed which accounts for 55% of the Los Peñasquitos WMA, had high priority (A) ratings for sediments and bacteria followed by benthic alteration which was given a B rating. Although the Poway sub-watershed, which accounts for 45% of the Los Peñasquitos WMA, had no A rated constituents, the highest priority constituents were sediments and bacteria which were given B ratings. A regional evaluation and description of the BLTEA is presented in the Regional Assessment Section 13. The complete tables used to calculate the ratings are presented in Appendix G. 8.6 Conclusions and Recommendations The Los Peñasquitos Creek run-off area accounts for approximately 60% of the Los Peñasquitos watershed management area. The major land uses within the contributing runoff area are parks (29%), residential (28%), and undeveloped (24%). For the Los Peñasquitos Creek WMA, only TDS was identified as a high frequency of occurrence COC, fecal coliform was identified as a medium frequency of occurrence COC, and turbidity, ammonia, orthophosphate, total coliform, and enterococcus were identified as low frequency of occurrence COC. Third party data collected in 2002 under SWAMP indicated that sulfate, manganese and toxicity were consistent problems throughout Los Peñasquitos watershed. The in-stream benthic community appears to be limited by unknown factors, and while high TDS levels may be enough of a stress to insects, other constituents not monitored in the Los Peñasquitos Creek MLS watershed may also be affecting the benthic invertebrate community. In Los Peñasquitos Lagoon, the final receiving waters for Los Peñasquitos Creek, relative rankings were four for chemistry, three for toxicity, and six for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Los Peñasquitos Lagoon had an overall rank of two. The relative quality within the lagoon increased compared to the 2003 ranking. In addition to the WMA assessment findings, the BLTEA ratings found sediments and bacteria to be the highest priority (A rated) constituents for the Los Peñasquitos WMA followed by benthic alteration which was given a B rating. The information provided from the triad matrix results used in conjunction with the BLTEA ratings can assist the jurisdictions in making informed decisions in developing their WURMP programs. The two reports also allow for an evaluation of where data gaps exist and where efforts should be targeted. Utilizing the BLTEA rating methods for future data evaluations would also allow for long-term BMP effectiveness assessment. Incorporation of additional useable data from other third party sources such as POTWs and non-profit organizations would also help to increase the confidence of the BLTEA ratings and overall WMA assessments. Recommendations for this watershed are to continue monitoring to gather long-term trend information and to investigate the potential role of physical habitat disturbance. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-1 9.0 MISSION BAY WATERSHED MANAGEMENT AREA 9.1 Monitoring Site Descriptions The Mission Bay watershed management area includes three hydrologic areas: Scripps (HA 906.30), Miramar (HA 906.40) and Tecolote (HA 906.50). Mission Bay drains both Rose and Tecolote Creeks. It was converted from a coastal marshland in the 1940s and now functions as a 4000-acre aquatic park. This watershed management area covers over 43,200 acres (Figure 9-1). The entire watershed management area lies within the City of San Diego. Land use within the watershed is primarily parks (26%) and residential (26%). Total population for the watershed in 2000 was more than 215,100. Urban runoff, sewage spills, and bacterial contamination have been reported as impairing water quality within the Mission Bay watershed management area. Restricted tidal flow within Mission Bay is limiting pollutant transport to the Pacific Ocean. This watershed management area supports a variety of ecosystems and provides many beneficial uses (Table 9-1). Major impacts to the Mission Bay watershed management area include surface water quality degradation, beach closures, sedimentation, habitat degradation and loss, invasive species, and eutrophication. Table 9-2 presents the water bodies that have been placed on the SWRCB 2002 303(d) list. Annual rainfall over the watershed ranges from 10.5 inches near the coast to 13.5 inches over the eastern portion of the watershed (Figure 9-1). The Tecolote Creek (TC, SD5) mass loading station is located along a trapezoidal, concrete-lined open channel on the east side of Morena Boulevard in San Diego. The contributing runoff area covers over 5,992 acres, which is approximately 14% of the Mission Bay watershed management area. The primary land uses within the contributing runoff area are residential (43%), and transportation (21%). Stream bioassessment monitoring in the Mission Bay WMA has occurred at sites in Rose Creek and Tecolote Creek. The Rose Creek site is located just downstream of the Highway 52 overcrossing. The stream bed and riparian zone have remained relatively undisturbed, although freeway and railroad development are in close proximity. The in-stream habitat of the riffles consists of moderately stable, smooth cobble and has perennial water flow. Tecolote Creek monitoring has occurred at two reaches. The upper reach is at Mt. Acadia Blvd. and the lower reach is upstream of Cross St., just above the beginning of the channelized portion of the creek. Both reaches are within the Tecolote Canyon Natural Park, and the stream bed and riparian zones are mostly undisturbed. The riffle substrate in Tecolote Creek is primarily unconsolidated gravel, but there is moderate treefall and roots within the streambed that add stability. Flow in the creek is year-round at the lower reach, but is generally quite low in the dry season. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-2 Figure 9-1. Mission Bay Watershed Management Area. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-3 Table 9-1. Beneficial uses within the Mission Bay watershed (Rose and Tecolote Creeks). Beneficial Uses Inland Surface Waters (a) Coastal Waters (b) Ground Waters Municipal and Domestic Supply Agricultural Supply Industrial Service Supply O z Industrial Process Supply Ground Water Recharge Navigation Contact Water Recreation z z Non-Contact Water Recreation z z Commercial and Sport Fishing z Warm Freshwater Habitat z Cold Freshwater Habitat z Biological Habitats of Special Significance Estuarine Habitat z Wildlife Habitat z z Rare, Threatened, or Endangered Species z z Marine Habitat z Migration of Aquatic Organisms z Shellfish Harvesting z Aquaculture Spawning, Reproduction and/or Early Development z = Existing O = Potential (a) Rose Canyon and Tecolote (b) Mission Bay Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) Table 9-2. Water bodies on the SWRCB 303(d) List in the Mission Bay watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor Pacific Ocean Shoreline Scripps 906.30 Bacteria Indicators Mission Bay Miramar 906.40 Bacteria Indicators, Eutrophic, Lead Tecolote Creek Tecolote 906.50 Bacterial Indicators, Cadmium, Copper, Lead, Toxicity, Zinc Source: SWRCB 2003 Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-4 The primary receiving water body for Tecolote Creek is Mission Bay, located within the City of San Diego. Mission Bay is a large man-made coastal embayment that encompasses an area of over 4,000 acres and 27 miles of shoreline. The Bay consists of numerous smaller bays, coves, inlets, and large stretches of open water. The three Ambient Bay and Lagoon monitoring sites in Mission Bay were located in the northeastern portion between the mouths of Rose Creek and Tecolote Creek (Figure 9-1). These creeks provide the majority of the freshwater input to Mission Bay, but the Bay is also influenced by over 100 storm drains. Rose and Tecolote Creeks and the majority of the storm drains that discharge to the Bay are connected to a diversion system that diverts dry weather flow to the sanitary sewer. The diversion system is not operational during wet weather. Mission Bay is connected to the ocean through a large rip-rapped channel on the Bay’s southwest corner. Tidal flushing is thought to be fairly good near the channel, but circulation is restricted in the eastern portion of the Bay, particularly near the mouth of Tecolote Creek. Mission Bay was created through extensive dredging and filling operations from the mid-1940s through the mid-1960s. An area in the southeast corner of the Bay was used as a municipal landfill during the 1950s. Currently, Mission Bay is surrounded by residential and commercial uses and Interstate 5 parallels the Bay’s eastern border. Mission Bay is listed on the SWRCB 2002 303(d) list for bacterial indicators, eutrophic conditions, and lead (Table 9-2). 9.2 Storm Water Monitoring Summary 9.2.1 2004-2005 Results The Tecolote Creek mass loading station has been monitored since 1993 for a total of 35 storms. For the 2004-2005 wet season, monitoring occurred on October 27, 2004 and February 11 and 18, 2005. The results for last 35 storms were compared to water quality objectives (WQO) to identify potential water quality concerns during storm flow (Table 9-3). Fecal coliform, total suspended solids (TSS), and turbidity levels exceeded WQOs during all three storm events monitored in 2004-2005. During the October 27, 2004 storm event, the WQO for chemical oxygen demand (COD), total phosphorus, copper, and zinc were also exceeded (Table 9-3). Concentrations of Diazinon were detected during the February 11, 2005 storm event, however concentrations did not exceed the water quality objectives during 2004-2005. No toxicity to Hyalella, Selenastrum, or Ceriodaphnia was observed in any of the Tecolote Creek samples collected in 2004-2005 (See Section 3.1.6.2 for details on toxicity testing). Table 9-3. Analytes measured at the Tecolote Creek mass loading station.12/11/1993 1/25/1994 11/10/1994 12/25/1994 1/11/1995 2/14/1995 11/1/1995 1/22/1996 1/31/1996 10/30/1996 11/21/1996 11/10/1997 12/6/1997 3/25/1998 11/8/1998 1/25/1999 3/15/1999 2/12/2000 3/5/2000 4/17/2000Electrical Conductivity umhos/cm 3220 393 414 185 1040 989 2220 53.5 1130 1690 726 6070 629 542 746 823 792Oil And Grease mg/L 15 USEPA Multi-Sector General Permit 1.96 3.1 1.2 1.28 0.82 1.55 11.4 2.4 2.5 2.4 3.6 1.6 0.6 0.7 <0.5 <0.5 4.16 1.56 2.96pH pH Units 6.5-8.5 Basin Plan 7.4 7.4 7.4 9.1 7.8Bacteriological Enterococci MPN/100 mLFecal Coliform MPN/100 mL 4,000 Basin Plan 2,400 <3011,000 17,000 >160,000 160,000 >16,000 16,000 8,000 16,000 160,0003,6408,8501,600 1,600 1,600 <2 1,600 <2Total Coliform MPN/100 mL 240,000 240,000 50,000 >160,000 >160,000 >160,000 >16,000 160,000 24,000 160,000 20,000 20,000 241,900 125,900 613,000 240 1,600 900Wet ChemistryAmmonia As Nitrogen mg/L 1.1 1.2 0.3 0.3 0.4 0.41 <0.2 <0.2 0.44 0.32 0.56 0.57 0.6 0.6 0.57 0.51 1.57 <0.1 <0.1Un-ionized Ammonia as Nμg/L 25 (a) Basin PlanBiological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit 20 20 23.3 <3 9.5 12.8 <5 <5 13.4 12.933 4322 30 5 9 11.7 2.38 5.7Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit28010015091 74126 13269 56 35 89 20 22 61 33 33 74 60 36Dissolved Organic Carbon mg/LDissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.2 0.4 <0.05 0.5 0.3 0.1 0.8 0.4 0.2 0.2 <0.1 0.1 0.12 0.52 0.15 0.1 <0.1 0.13 <0.1Nitrate Nitrogen As N mg/L 10 Basin Plan 4.2 <0.1 0.8 0.8 0.8 1.1 1 1.7 0.54 0.5 0.52 0.7 0.53 3.3 0.6 2.3Nitrite Nitrogen As N mg/L 1 Basin Plan 0.15 <0.05 <0.05 <0.05 <0.050.06 0.05 0.1 <0.05 0.05 0.065 <0.05 <0.05Surfactants (MBAS) mg/L 0.5 Basin Plan 0.310.77 0.520.23 0.17 0.26 0.14 <0.1 <0.1 <0.1 <0.1 0.05 0.20.510.08 <0.05 0.48 0.24 0.2Total Dissolved Solids mg/L1500Basin Plan by watershed 400 750 2300 260 370 680 1270 842 256 546 362 1730 447 318 1492 563 660 279 304 302Total Kjeldahl Nitrogen mg/L 10 3.7 3.7 2.3 3.6 3.9 2.6 0.89 2.9 2.7 1.6 <1 1.1 0.12 2.93 1.85 2.1 0.77 1.83Total Organic Carbon mg/LTotal Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.3 0.5 <0.05 1.1 0.4 0.5 <0.2 <0.2 0.8 0.5 0.7 0.12 0.23 0.61 0.16 0.16 0.21 0.34 0.4Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit880 1500 140 30076130 140 24492348 104 410 503 2024 913 5405547880 87Turbidity (NTU) NTU 20 Basin Plan 836 43 66 39 79.617.4 12.1120 131 160 27 96 84 4517 1763 60Pesticides Chlorpyrifosμg/L 0.02 CA Dept. of Fish & Game<0.05* <0.5* <0.5* <0.5* <0.5*Diazinonμg/L 0.08 CA Dept. of Fish & Game0.4 0.28 0.41<0.5* <0.5*0.18Malathionμg/L 0.43 CA Dept. of Fish & GameHardness Total Hardness mg CaCO3/L 210 550 1100 140 120 340 547 363 111 268 253 694 186 124 148 218 277 216 126 105Total Metals Antimony mg/L 0.006 Basin Plan 0.0014 0.0012 0.0019 <0.001 <0.001 0.0012 <0.0015 <0.003 0.003 <0.0015 <32* <32* <0.0015 <0.0015 <0.0015 <0.0015 <0.0015 <0.0015Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan 0.0069 0.013 <0.005 0.0089 <0.005 <0.005 0.008 0.009 0.007 0.001 <0.053* <0.053* 0.004 0.0015 0.002<0.001 0.006 0.009Cadmium mg/L (b) 40 CFR 131 0.0023 0.0027 0.0003 0.0008 0.0003 0.0003 0.0009 0.0016 0.0019 <0.00025 <0.004 <0.004 0.004 <0.00025 <0.00025 <0.000250.001 <0.00025Chromium mg/L (b) CTR (Cr VI) 0.0017 0.006 0.0028 0.0019 0.0028 0.0051 <0.005 0.010 <0.010 <0.005 <0.007 0.019 <0.005 0.009 0.056 <0.005 <0.005 <0.005Copper mg/L (b) 40 CFR 131 0.030 0.054 0.00680.0250.010 0.012 0.0330.0500.020 0.0090.056 0.146<0.005 <0.005 <0.0050.0360.017 <0.005Lead mg/L (b) 40 CFR 131 0.140 0.200 0.003 0.035 0.019 0.013 0.0173 0.050 0.026 <0.001 <0.042 <0.042 0.040 0.003 0.023 0.027 <0.001 <0.001Nickel mg/L (b)/0.1 40 CFR 131/ Basin Plan 0.022 0.018 0.016 0.0065 <0.005 0.005 0.014 <0.010 <0.010 <0.005 <0.015 <0.015 0.020 <0.005 0.009 <0.005 <0.005 <0.005Selenium mg/L 0.02 40 CFR 131 <0.0005 0.0006 <0.0005 0.0012 0.0006 0.0005 0.0023 0.002 0.003 <0.001 <0.075 <0.075 0.004 <0.001 <0.001 <0.001 <0.001<0.001Zinc mg/L (b) 40 CFR 1310.7800.490 0.034 0.170 0.059 0.0620.1370.230 0.120 0.069 0.068 0.130 <0.025 <0.025 0.071 0.160 0.012 0.050Dissolved Metals Antimony mg/L (e) 40 CFR 131 0.0019 0.001 <0.001 <0.001 <0.0015 <0.0015 <0.003 <0.003 <0.0015 <0.0015 <0.0015Arsenic mg/L 0.34 (c) 40 CFR 131 <0.005 <0.005 <0.005 <0.005 0.005 0.003 0.002 0.002<0.001 <0.001 <0.001Cadmium mg/L (b) 40 CFR 131 0.0003 <0.0002 <0.0002 <0.0002 <0.00025 <0.00025 <0.0005 0.0005 <0.00025 <0.00025 <0.00025Chromium mg/L (b) 40 CFR 131 0.0019 <0.001 0.0014 <0.001 <0.005 <0.005 <0.010 <0.010 <0.005 <0.005 <0.005Copper mg/L (b) 40 CFR 131 0.0059 <0.005 0.005 0.0059 <0.008 0.006 0.010 <0.010 <0.005 <0.005 <0.005Lead mg/L (b) 40 CFR 131 0.0015 <0.001 <0.001 0.0019 0.002 <0.001 <0.002 <0.002 <0.005 <0.001 <0.001Nickel mg/L (b) 40 CFR 131 0.0150 <0.005 <0.005 <0.005 <0.005 <0.005 <0.010 <0.010 <0.005 <0.005 <0.005Selenium mg/L 0.02 (d) 40 CFR 131 <0.0005 <0.0005 <0.0005 <0.0005 <0.001 <0.001 <0.002 <0.003 <0.001 <0.001 <0.001Zinc mg/L (b) 40 CFR 131 0.039 0.013 0.017 0.016 0.026 <0.025 0.230 <0.0500.016 0.012 <0.001ToxicityCeriodaphnia 96-hr LC50 (%) 100Ceriodaphnia 7-day survival NOEC (%) 100Ceriodaphnia 7-day reproduction NOEC (%) 100Hyalella 96-hr NOEC (%) 100Selenastrum 96-hr NOEC (%) 100See last page for footnotes and source references1994-95 1995-96 1997-98 1998-99 1999-001993-94General / Physical / Organic1996-97ANALYTE UNITS WQO SOURCE Table 9-3. Analytes measured at the Tecolote Creek mass loading station.Electrical Conductivity umhos/cmOil And Grease mg/L 15 USEPA Multi-Sector General PermitpH pH Units 6.5-8.5 Basin PlanBacteriological Enterococci MPN/100 mLFecal Coliform MPN/100 mL 4,000 Basin PlanTotal Coliform MPN/100 mLWet ChemistryAmmonia As Nitrogen mg/L Un-ionized Ammonia as Nμg/L 25 (a) Basin PlanBiological Oxygen Demand mg/L 30 USEPA Multi-Sector General PermitChemical Oxygen Demand mg/L 120 USEPA Multi-Sector General PermitDissolved Organic Carbon mg/LDissolved Phosphorus mg/L 2 USEPA Multi-Sector General PermitNitrate Nitrogen As N mg/L 10 Basin PlanNitrite Nitrogen As N mg/L 1 Basin PlanSurfactants (MBAS) mg/L 0.5 Basin PlanTotal Dissolved Solids mg/L1500Basin Plan by watershedTotal Kjeldahl Nitrogen mg/LTotal Organic Carbon mg/LTotal Phosphorus mg/L 2 USEPA Multi-Sector General PermitTotal Suspended Solids mg/L 100 USEPA Multi-Sector General PermitTurbidity (NTU) NTU 20 Basin PlanPesticides Chlorpyrifosμg/L 0.02 CA Dept. of Fish & GameDiazinonμg/L 0.08 CA Dept. of Fish & GameMalathionμg/L 0.43 CA Dept. of Fish & GameHardness Total Hardness mg CaCO3/LTotal Metals Antimony mg/L 0.006 Basin PlanArsenic mg/L 0.34/0.05 40 CFR 131/ Basin PlanCadmium mg/L (b) 40 CFR 131Chromium mg/L (b) CTR (Cr VI)Copper mg/L (b) 40 CFR 131Lead mg/L (b) 40 CFR 131Nickel mg/L (b)/0.1 40 CFR 131/ Basin PlanSelenium mg/L 0.02 40 CFR 131Zinc mg/L (b) 40 CFR 131Dissolved Metals Antimony mg/L (e) 40 CFR 131Arsenic mg/L 0.34 (c) 40 CFR 131Cadmium mg/L (b) 40 CFR 131Chromium mg/L (b) 40 CFR 131Copper mg/L (b) 40 CFR 131Lead mg/L (b) 40 CFR 131Nickel mg/L (b) 40 CFR 131Selenium mg/L 0.02 (d) 40 CFR 131Zinc mg/L (b) 40 CFR 131ToxicityCeriodaphnia 96-hr LC50 (%) 100Ceriodaphnia 7-day survival NOEC (%) 100Ceriodaphnia 7-day reproduction NOEC (%) 100Hyalella 96-hr NOEC (%) 100Selenastrum 96-hr NOEC (%) 100See last page for footnotes and source referencesGeneral / Physical / OrganicANALYTE UNITS WQO SOURCE10/27/2000 1/8/2001 2/13/2001 11/29/2001 2/17/2002 3/8/2002 11/8/2002 12/16/2002 2/11/2003 11/1/2003 11/12/2003 2/3/2004 10/27/04 02/11/05 02/18/052950 2350 338 3300 5090 3650 1694 311 3224740 4490 850 167 473 1994 1 1 <1 <1 2 2.00 1.69 3.161.05 <1 <1 <1 1.32 <10% 0.127.7 7.4 7.7 6.67 7.61 7.557.67 7.73 6.85 6.78 6.90 7.143% 0.039,000 17,000 5,000 7,000 7,000 3,000 35,000 23,000 14,00011,000 8,000 80,000 300,000 50,000 30,00050,000 21,0001,300 3,0005,000 7,000 110,000 13,0002,20050,000 17,000 13,00070,000 13,000 17,00057% 5.73170,000 220,000 8,000 5,000 22,000 11,000 300,000 50,000 30,000230,000 50,000 50,000 800,000 130,000 130,0000.91 0.5 0.4 0.9 0.19 0.28 0.44 0.34 0.260.38 <0.1 0.14 0.39 0.35 <0.10.64 3.79 2.45.19 0.79 0.24 0.6 0.1 0.50% 0.0214 13.2 <2 3.6 4.5 4.6 6.75 22.4 25.422.9 4.1968.47.45 7.75 3.659% 0.47122118 88 6015557 79 67125 2119914817388 2529% 0.758.3 13.2 15.926.1 20.5 6.46 34 7.8 4.440.14 0.28 0.27 0.11 0.4 0.13 0.16 0.32 0.820.47 0.27 0.06 0.89 0.46 <0.050% 0.131 0.7 0.6 0.4 0.5 0.4 0.81 0.84 0.901.84 0.95 0.55 0.53 0.5 0.420% 0.090.09 0.08 <0.05 <0.05 <0.05 <0.05 <0.05 0.06 0.060.07 0.06 <0.05 <0.05 <0.05 <0.050% 0.04<0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.1 <0.1 <0.1<0.5 <0.5 <0.5 <0.5 <0.5 <0.59% 0.43440 2320 250 1890 2200 2490 757 220 3732660 1070 1190 174 627 2852.15 6.5 0.67 2.2 2 0.39 2.1 1.4 3.73 1.8 3.4 6 1 6.221.9 27.0 15.435.5 20 18.8 36.4 12.1 8.270.5 0.32 0.38 0.24 0.65 0.22 0.6 1.84 1.031.14 0.34 0.582.870.47 0.53% 0.271037517934 68 33158 346 301 102<20 <202180 229 24569% 3.7573.8 63 85 21.38.99 10.7102 200 200 34.713.5201540 44.7 67.474% 3.98<0.05* <0.5*0.03<0.03* <0.03* <0.03* <0.03*0.087<0.03*<0.01 <0.01 <0.01 <0.01 <0.01 <0.0123% 2.140.47<0.50.16 0.22 0.19 0.09 0.185 0.095 0.155 0.1160.073 0.053 <0.01 0.051 <0.0146% 1.391.8<0.5* <0.1 <0.10 <0.100.87<0.01 0.269 0.085 <0.01 0.063 <0.0113% 0.54209 1070 107 962 1180 1350 344 245 2981470 1300 591 126 330 152<0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 0.0060.009 0.007<0.005 <0.005 <0.005 <0.005 <0.0056% 0.300.007 0.007 0.005 0.001 0.004 0.004 0.008 0.015 0.0130.009 0.006 0.016 0.006 0.009 <0.0020% 0.15<0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.001 0.001 <0.001 <0.0010% 0.080.006 <0.005 0.006 0.006 0.006 <0.005 <0.0050.02 0.018 0.005 <0.005 0.015 <0.005 <0.005 <0.0050% 0.000.023 0.0120.0160.008 0.009 0.0090.030.0500.038 0.011 0.009 0.0440.0380.018 0.01027% 0.890.015 0.008 0.018 0.004 0.004 <0.002 0.018 0.052 0.0400.006 0.003 0.034 0.065 0.019 0.0110.011 0.009 0.005 0.005 0.006 0.006 0.008 0.011 0.0120.007 0.005 0.012 0.012 0.005 0.0030% 0.01<0.002 0.006 <0.002 <0.002 0.003 0.002 <0.004 <0.004 <0.004<0.004 <0.005 <0.005 <0.005 <0.005 <0.0056% 0.190.080 0.040 0.080 0.022 0.028 0.034 0.0960.208 0.235 0.047 0.033 0.2060.2370.086 0.0659% 0.49<0.002 <0.002 <0.002 <0.002 <0.002 <0.002 0.002 0.002 0.002<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050.003 0.003 0.002 0.001 0.001 0.002 0.003 0.004 0.0030.004 0.003 0.003 <0.002 <0.002 <0.0020% 0.01<0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.02<0.005 <0.005 <0.005 0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.000.010 0.006 <0.005 0.006 <0.005 <0.005 0.008 0.0060.042<0.005 <0.005 <0.005 <0.005 0.006 <0.0054% 0.18<0.002 <0.002 0.003 <0.002 <0.002 <0.002 <0.002 0.005 <0.002<0.002 <0.002 <0.002 <0.002 0.003 <0.0020% 0.010.009 0.008 0.002 0.004 0.005 0.005 0.004 <0.002 0.0030.005 0.003 0.003 <0.002 0.003 <0.0020% 0.00<0.002 0.004 <0.002 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004<0.004 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.070.050 0.030 <0.020 <0.020 0.029 <0.020 0.021 0.039 0.144<0.02 <0.02 <0.02 <0.02 <0.02 <0.020% 0.1125100 100 >100 >100 >100 >100 >10070.71>100 >100 >100 >100 >100 >100 13% 0.3612.5 5010050100 100 100 10050100 100 100 100 100 100 27% 0.9350100 100 100 10050 50100 100 100 100 100 25% 0.5010025 12.5100 100 100 100 100 100 100 100 100 100 100 100 13% 0.8010025100 100 100 100 100 100 100 100 100 100 8% 0.332004-052002-032000-01Frequency Above WQOMean Ratio to WQO2003-042001-02 Table 9-3. Analytes measured at the Tecolote Creek mass loading station.Sources(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(e) USEPA has not published an aquatic life criterion value.USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Table 3 - Parameter benchmark values.USEPA Federal Register Document 40 CFR Part 131, May 18, 2000.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.Shaded text – exceeds water quality objective.Blank spaces have been verified and no data is available due to changes in the monitoring program.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.* Indicates detection limit exceeds water quality objective. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-8 9.2.2 Relationships/Analyses Water quality monitoring in Tecolote Creek has been conducted since 1993, thus, it is possible to assess storm water runoff over a longer temporal scale than the other sites in San Diego County with mass loading stations. A review of the data from Tecolote Creek suggests that there are four parameters that are consistently problematic in storm water runoff, including fecal coliform bacteria, TSS, turbidity, and Diazinon. Fecal coliform bacteria originate from the feces of all warm blooded animals. Thus, its presence in the environment can be indicative of natural sources (e.g., birds, rodents, cattle, etc.) as well as human sewage. Fecal coliform bacteria are ubiquitous in the environment and are frequently found in high densities in urban runoff. In Tecolote Creek, the wet weather water quality objective for fecal coliform (4,000 MPN/100 ml) has been exceeded in 22 of the 34 (65%) storm events where it has been analyzed since 1993. Densities have been uniformly high in nearly all the samples collected and there is no apparent temporal trend for this COC during storm events. Total suspended solids are solid materials suspended in water than can be trapped by a filter. It can include a variety of material such as sand, silt, and clay, decaying plant and animal material, industrial waste, and sewage. High TSS levels can cause many problems for aquatic life in a stream, including the macroinvertebrate community. In addition, high TSS levels can be related to elevated levels of bacteria, nutrients, pesticides, and metals, as these constituents often adhere to particles in the water associated with TSS. Turbidity is a measure of water clarity and is determined by the extent to which particles suspended in a water sample scatter a beam of light. Thus, TSS and turbidity are often co-related. In Tecolote Creek, the water quality objective for TSS (100 mg/L) has been exceeded in 71% (24 of the 34) of the storm water samples collected since 1993 and the objective for turbidity has been exceeded in 74% (26 out of 35) of the samples. Diazinon is an organophosphate insecticide. Like all pesticides in this chemical family, it kills insects and other organisms through its effect on the nervous system. It inhibits an enzyme, acetylcholinesterase, which breaks down choline. Choline is used to transmit nervous impulses across junctions between nerve cells. In the presence of organophosphates, choline builds up in the junction, resulting in incoordination, convulsions, and ultimately death. Diazinon and other organophosphate pesticides can have a profound impact on the macroinvertebrate population of a stream. In Tecolote Creek, Diazinon has been monitored at the mass loading station during 21 storm events since 1998. Of these, it has exceeded the water quality objective (0.08 μg/L) 13 times (62%), with concentrations ranging from 0.095 to 0.47 μg/L. Review of the data suggests that there is a significant decreasing trend in Diazinon concentrations (R2=0.30). In addition to the wet weather monitoring results discussed above, concentrations of MBAS (R2=0.15), Ammonia as N (R2=0.14), total cadmium (R2=0.14), and total lead (R2=0.17) have shown statistically significant decreasing trends from 1993 through 2005. Increasing trends have been observed for total phosphorus (R2=0.13) and enterococcus bacteria (R2=0.46). While these are significant trends, those for the metals and nutrients have low R2 values which indicate large variability of the data. Toxicity testing has been performed on storm water from the Tecolote Creek MLS for the past five years or 15 events (See Section 3.1.6.2 for details on toxicity testing). During the first two years, significant toxicity to the test organisms was observed (Table 9-3); however, during the last three years toxicity was only observed to Ceriodaphnia and it appears to be related to a specific storm event rather than a persistent problem. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-9 In order to illustrate the magnitude of the water quality exceedances for 2004-2005, the ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern. The results are shown in Figure 9-2. The largest single exceedance was for turbidity, which exceeded the WQO by 27 times during the October 27, 2004 storm. There were also noticeable single exceedances for TSS (22 times the WQO) and for fecal coliform (17.5 times the WQO) during the October 27, 2004 storm. The average magnitude of water quality exceedances was also determined for each constituent by calculating the mean ratio of water quality results to the WQOs from all storm events from October 2001 through April 2004. Mean ratios are illustrated in Figure 9-2. The largest average exceedance for the period of record was for fecal coliform (6.1 times the WQO). The second largest average exceedance was for turbidity, which exceeded the WQO by 4.4 times. TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 20 Ratio to WQOMean Ratio (Oct 01 to Apr 04) 10/27/04 2/11/05 2/18/05 Above WQO Figure 9-2. Tecolote Creek water quality ratios. In addition to the wet weather monitoring discussed above, there are 16 sites in the Mission Bay WMA where water quality is monitored during dry weather. Of these, five are located upstream of the mass loading station on Tecolote Creek. The dry weather data for this site is useful, but it is important to remember that it represents only one year of monitoring (See Section 3.4 for details on dry weather sampling). Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-10 Table 9-4 shows exceedances of water quality objectives and the average ratio of exceedance for COC that were measured during the 2004 dry weather monitoring program. During dry weather sampling, there were exceedances of action levels at the monitoring sites located above the mass loading station for pH, turbidity, phosphorus, total coliform, and enterococcus. Of these, only turbidity had an average ratio of exceedance greater than one. A map for the WMA showing DWS exceedances is found in Figure 9-3. Pie symbols appear at dry weather stations that have had water quality exceedances. The colored slices of the pie show the different constituent groups that contributed to the exceedances. The constituents that had exceedances during both the dry and wet weather monitoring in 2004-2005 include total phosphorus and turbidity. 9.2.3 Third Party Data Third party data was collected from two locations in 2002 within the Mission Bay watershed under the Surface Water Ambient Monitoring Program (SWAMP) and was provided by the San Diego Regional Water Quality Control Board. The sampling sites were located on Tecolote Creek near the mass loading station and on Rose Canyon Creek. Grab samples were collected from each station during dry weather once in March, April, June and September, 2002 for Rose Canyon Creek and in March, April and June for Tecolote Creek. The site was dry in September, therefore samples were not collected. Results are presented in Table H-2 in Appendix H. Data collected from Tecolote Creek were compared to the mass loading station and dry weather data results to provide qualitative assessments with current wet and dry weather results. The Rose Canyon Creek station was too spatially disconnected from the MLS to correlate the data with any of the wet and dry weather monitoring results, however, exceedances were noted. There were water quality objective exceedances for sulfate, manganese and toxicity at the Tecolote Creek station. Sulfate and manganese exceeded objectives during all three sampling events. Toxicity at Tecolote Creek was evident for Selenastrum growth during all three sampling events and for Ceriodaphnia dubia survival and reproduction during two sampling events. All other constituents were below their respective water quality objectives. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedance was for toxicity during wet weather. Toxicity to Ceriodaphnia survival has been observed in 4 out of 15 storm events; Ceriodaphnia reproduction has been affected in 3 out of 15 storm events; toxicity to Hyalella has been observed in 2 out of 15 storm events and toxicity to Selenastrum has been observed 1 out of 12 storm events. Exceedances observed at Rose Canyon Creek included sulfate, manganese, turbidity, pH, Diazinon and toxicity. Sulfate concentrations exceeded objectives during all four sampling events; manganese, turbidity and Diazinon exceeded objectives during two sampling events and pH exceeded objectives during one event. Toxicity to at least one test organism was evident during all sampling events. Table 9-4. Mission Bay WMA 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* St. Dev. Ratio of Exceedance pH 1 5 0.23 0.45 Turbidity 2 5 1.43 1.92 Phosphorus 1 5 0.79 0.61 Total Coliform 1 5 1.44 2.58 Enterococcus 1 5 0.69 0.58 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-11 Figure 9-3. Mission Bay WMA dry weather exceedance map. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-12 9.2.4 TIEs TIE testing was not performed on Tecolote Creek samples. This mass loading station has not been identified as a TIE candidate site based upon the Triad Decision Matrix. 9.2.5 Summary and Conclusions Four parameters appear to be consistently problematic in storm water runoff at the Tecolote Creek MLS: fecal coliform bacteria, TSS, turbidity, and Diazinon. High levels of other constituents occur occasionally, but do not appear to be consistently problematic. Diazinon, MBAS, ammonia, total cadmium, and total lead appear to be decreasing over time, while enterococcus and total phosphorus concentrations appear to be increasing. There were five dry weather monitoring sites located upstream of the mass loading station that were monitored in 2004-2005. The data from these sites suggested that the water quality objectives for turbidity and total phosphorus were exceeded in both dry and wet weather. Although there has been toxicity associated with storm water in previous monitoring years, it appears to be related to specific storm events rather than a persistent pattern. Third party data collected in 2002 indicated that sulfate, manganese and toxicity were consistent problems at the Tecolote Creek monitoring station. 9.3 Stream Bioassessment Stream bioassessment in the Mission Bay WMA included two urban affected monitoring sites representing two different watersheds. One site was in Rose Creek, downstream of the confluence with San Clemente Canyon Creek and downstream of Highway 52. The other site was in Tecolote Creek in Tecolote Canyon Natural Park, near the downstream border of the Park. 9.3.1 Results and Discussion Rose Creek near Highway 52: MB-RC The Rose Creek monitoring site had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Poor for the October 2004 survey, and Very Poor for the May 2005 survey (Table 9-5) (See Section 3.2 for details on the sampling approach). Taxa richness was fair to low, with 23 and 9 unique taxa collected, and with 0 and 3 EPT taxa in October 2004 and May 2005, respectively. There were no organisms collected that are highly intolerant to impairment, and the percent tolerant taxa comprised 12% of the community in October and 11% of the community in May. The physical habitat of the reach was nearly optimal, with a substrate of large cobble, tree roots, and emergent vegetation providing a variety of stable niche space for macroinvertebrate colonization. The live oak and sycamore riparian zone was mostly undisturbed, and the stream had good canopy cover. Water quality was somewhat impaired, with high specific conductance values of 3.651 mS/cm in October 2004 and 3.196 mS/cm in May 2005 (Table 9-5). Values for pH were 8.1 and 7.7 for the October and May surveys, respectively. The benthic community was seasonally variable. In October 2004, the site was dominated by the snail, Fossaria, and Oligochaete earthworms (Table 9-6). In May, the site was dominated by the minnow mayfly, Baetis, the black fly, Simulium, and Chironomid midges. The increased taxa richness in the May survey was most likely due to increased numbers of Dipteran taxa (true flies). Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-13 Table 9-5. Selected Biological Metrics and Physical Measures of the Mission Bay WMA. Mission Bay Watershed Management Area Rose Creek near Highway 52 (MB-RC) Tecolote Creek in Tecolote Canyon Natural Park (TC- TCNP) Survey Oct-04 May-05 Oct-04 May-05 Index of Biotic Integrity/ Qualitative Rating 21 Poor 10 Very Poor 20 Poor 2 Very Poor Metrics Taxa Richness 23 9 18 13 EPT Taxa (mayflies, stoneflies, and caddisflies) 0 3 1 2 % Intolerant Taxa 0% 0% 0% 0% % Tolerant Taxa 12% 11% 32% 9% Average Tolerance Value 6 5.8 6.8 6.2 % Collector Filterers +Collector Gatherers 24% 98% 73% 97% Physical Measures Elevation 65 55 Physical Habitat Score 146 160 140 151 Riffle Velocity (ft/sec) 0.9 1.3 0.9 1.4 Substrate Composition Silt 5% Sand 3% 10% 2% 17% Gravel 20% 7% 16% 25% Cobble 74% 72% 50% 58% Boulder 3% Roots 27% Bedrock/solid 8% Water Quality Temperature ºC 19.8 15.3 18.4 18.5 pH 8.1 7.7 7.44 7.8 Specific Conductance (ms/cm) 3.651 3.196 7.992 3.594 Relative Chlorophyll (μg/L) 5.7 2.9 2.3 3.4 Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-14 Table 9-6. Mission Bay WMA Community Summary. Taxon Common Name Percent Composition Tolerance Value Functional Feeding Group Fossaria snail 53% 8 Scraper Oligochaeta earth worm 20% 5 Collector Gatherer Physa aquatic snail 10% 8 Scraper Ceratopogonidae biting midges 5% 6 Predator Oct-04 Muscidae common fly 2% 6 Predator Baetis minnow mayfly 32% 5 Collector Gatherer Simulium black fly 24% 6 Collector Filterer Chironomidae non-biting midges 22% 6 Collector Gatherer/Filterer Ostracoda seed shrimp 10% 8 Collector Gatherer Rose Creek near Highway 52 (MB-RC) May-05 Oligochaeta earth worm 10% 5 Collector Gatherer Hyalella amphipod 22% 8 Collector Gatherer Dasyhelea biting midge 20% 6 Collector Gatherer Chironomidae non-biting midges 19% 6 Collector Gatherer/Filterer Argia dancer damselfly 14% 7 Predator Oct-04 Ostracoda seed shrimp 9% 8 Collector Gatherer Chironomidae non-biting midges 51% 6 Collector Gatherer/Filterer Simulium black fly 36% 6 Collector Filterer Ostracoda seed shrimp 6% 8 Collector Gatherer Physa aquatic snail 2% 8 Scraper Tecolote Creek in Tecolote Canyon Natural Park (TC-TCNP) May-05 Baetis minnow mayfly 1% 5 Collector Gatherer The Mission Bay mass loading station sampled runoff from a separate drainage from Rose Creek, therefore storm water information could not be correlated with the bioassessment site. Tecolote Creek in Tecolote Canyon Natural Park: TC-TCNP The Tecolote Creek monitoring site had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Poor for the October 2004 survey, and Very Poor for the May 2005 survey (Table 9-5). As in past surveys, the IBI scores varied considerably, ranging from 20 in October to 2 in May. Taxa richness was fair to low, with 18 and 13 unique taxa collected, and with 1 and 2 EPT taxa collected in October and May, respectively. There were no organisms collected that are highly intolerant to impairment, and the percent tolerant taxa comprised 32% and 9% of the community in October 2004 and May 2005, respectively. The physical habitat of the reach was near optimal, with a substrate primarily of unconsolidated gravel and small cobble, with emergent vegetation and tree roots providing additional niche space. The riparian zone was mostly undisturbed live oak, and the stream had good canopy cover. Water quality was poor, with the highest specific conductance value of any site in the San Diego County program during the October survey. Values were 7.992 ms/cm in October and 3.594 ms/cm in May. Values for pH were 7.4 and 7.8 for the October and May surveys, respectively. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-15 The benthic community was seasonally variable. The October survey was dominated by the amphipod, Hyalella; the biting midge, Dasyhelea; Chironomid midges, and the damselfly, Argia (Table 9-6). The May survey was dominated by Chironomid midges and the black fly, Simulium. The Tecolote Creek mass loading station was located several thousand feet downstream of the bioassessment station, and water quality measures may be correlated with the site although some urban runoff would have entered the stream below the bioassessment site. Constituents of concern identified during storm water sampling that would have a negative impact on the biological community included total suspended solids and turbidity (Table 9-3). Exceedances in total dissolved solids, pesticides, and toxicity to Ceriodaphnia and Hyalella have occurred historically, but were not evident in 2004-2005. Total metals, including copper, lead, and zinc were detected at levels that would prevent the colonization of highly sensitive organisms. 9.3.2 Summary and Conclusions The Mission Bay WMA was sampled at two sites. One site was in Rose Creek, downstream of Highway 52, and the other site was in Tecolote Creek in Tecolote Canyon Natural Park. The macroinvertebrate community of both sites had Index of Biotic Integrity ratings of Poor in October and Very Poor in May, with substantial seasonal variation in the total IBI scores. 9.4 Ambient Bay and Lagoon Monitoring 9.4.1 Results and Discussion 9.4.1.1 Phase I Results and Discussion Phase I sediment samples were collected in Mission Bay for the ABLM Program on June 2, 2004 (See Section 3.3 for details on the sampling approach). Mission Bay was treated as a single water body representing the receiving waters of both Rose Creek, which discharges to the northeast end of the Bay, and Tecolote Creek, which discharges to the southeast end of the Bay. The sampling locations are shown in Figure 9-4. The median grain size of the nine sites sampled in Mission Bay was extremely variable, ranging from 2.37 μm at Site 3L-1 in the inner stratum to 261 μm at Site 2M-1 in the middle stratum (Table 9-7). Sand was the dominant constituent in the outer and middle strata sites, with sediments in the inner stratum of Mission Bay, nearest the mouths of Rose and Tecolote Creeks, being much smaller grained. TOC concentrations also tended to be lower in the middle areas Figure 9-4. Map of Phase I site locations in Mission Bay. Sites with yellow triangles were selected for Phase II assessment. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-16 of Mission Bay compared to the inner and outer stratums. The one exception to these patterns was Site 1L-1 in the outer stratum, which had similar sediment characteristics to inner stratum sites. Due to the high fine grain size and high TOC levels found in sediments in the inner stratum of Mission Bay, two inner stratum sites (3L-1 and 3R-1) and one outer stratum site (1L-1) were selected for Phase II assessment (Table 9-7). Table 9-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Rose Creek and Tecolote Creek outfalls in Mission Bay. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II MB-1L-1 0.00 17.2 37.63 45.19 5 8 82.82 2.38 7 7 14 * Yes MB-1M-1 0.05 92.0 3.92 4.06 181 187 7.98 0.55 2 2 4 MB-1R-1 1.52 33.4 41.1 23.9 27.8 11.7 65.07 2.17 5 6 11 MB-2L-1 0.03 66.3 23.77 9.88 87 54 33.65 0.96 4 4 8 MB-2M-1 0.20 95.3 2.0 2.43 261.0 242.8 4.47 0.25 1 1 2 MB-2R-1 0.34 84.7 7.3 7.6 109.3 103.43 14.93 0.59 3 3 6 MB-3L-1 1.69 5.74 36.7 55.9 2.37 NC 92.58 2.52 9 9 18 * Yes MB-3M-1 0.62 14.1 41.1 44.2 6.65 NC 85.27 1.72 8 5 13 MB-3R-1 1.31 17.3 32.1 49.3 4.19 NC 81.43 2.49 6 8 14 * Yes Mean of all Sites 0.64 47.34 25.08 26.94 76.04 101.15 52.02 1.51 St. Dev. 0.68 36.90 16.41 21.70 93.03 96.27 36.48 0.93 NC = Not calculable (%silt + %clay > 84%) 9.4.1.2 Phase II Results and Discussion The three sites selected in Mission Bay as part of Phase I were sampled in Phase II on July 13, 2004. Sediments from Sites 1L-1, 3L-1 and 3R-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 9-8. Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, seven metals were detected above the detection limit in Mission Bay: arsenic, chromium, copper, lead, nickel, selenium, and zinc (Table 9-8). All of these metals except selenium were also found in all the other embayments assessed in the ABLM Program. Concentrations of metals were relatively high, with arsenic, copper, lead and zinc exceeding their respective ERL, but none exceeded their respective ERM value. During the 2003 ABLM program the same seven metals were detected with the exception being cadmium detected instead of selenium. Concentrations of the 2003 metals were low and none exceeded their respective ERM value. However, concentrations of arsenic, copper, and lead exceeded their respective ERL values in 2003. There were no PAHs, PCBs, or pesticides found above the detection limit in Mission Bay during the 2004 program. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was 0.299. This value exceeded the threshold of 0.10 and was the highest in the ABLM Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-17 Program. Sediments with mean ERM-Q values above this threshold have a higher probability of producing adverse biological effects than those with mean ERM-Qs below the threshold (Long et al. 1998). During the 2003 ABLM program the threshold was also exceeded with a mean ERM quotient of 0.199. Toxicity. The percent survival of E. estuarius exposed to Mission Bay sediments in a 10-day acute toxicity test was 81 % which was not significantly different from that of the Control (99%) (Table 9-8). This suggests that the Mission Bay sediments were not toxic to the test organisms. This is similar to the results from the 2003 ABLM program where no toxicity was observed. Table 9-8. Summary of chemistry, toxicity, and benthic community structure in Mission Bay. CHEMISTRY* TOXICITY* BENTHIC COMMUNITY Analyte ERL ERM Result ERM- Q Percent Survival Index 1L-1 3L-1 3R-1 Mean St. Dev. Total METALS (mg/kg) Abundance 672 453 1433 853 514 2558 Antimony NA NA <1.74 NA Richness 41 33 56 43.3 11.7 87 Arsenic 8.2 70 12.7 0.181 Diversity 2.44 2.54 2.90 2.62 0.24 NA Cadmium 1.2 9.6 <0.174 NA Evenness 0.66 0.73 0.72 0.70 0.04 NA Chromium 81 370 43.2 0.117 Dominance 6 6 9 7.0 1.73 NA Copper 34 270 148 0.548 Lead 46.7 218 50.4 0.231 Nickel 20.9 51.6 12.9 0.250 Selenium NA NA 1.96 NA Zinc 150 410 191 0.466 Mean ERM-Q 0.299 81% Not significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value Benthic Community Structure. A total of 2558 organisms were collected from Mission Bay, representing 87 taxa (Table 9-8). During the 2003 ABLM program a total of 2,932 organisms were collected, representing 69 taxa. Site 3R-1 in the inner stratum had greater taxa abundance, richness, dominance and diversity than Sites 1L-1 and 3L-1. However, evenness was greatest at Site 3L-1, in the inner stratum. Based on these indices, the benthic community structure in Mission Bay had a rank of 1 where 1 represents the healthiest community with the lowest combined index score and 12 the least- healthy community. As in 2003, the barley snail, Barleeia sp., was the most common species of the benthic community in Mission Bay during the 2004 program, accounting for 8.6% (32.1% in 2003) of all the animals collected (Table 9-9). The second most abundant species was the Polychaete, Exogone lourei, that accounted for 8.5% of the benthic community. Another polychaete worm, Aphelochaeta sp., was the third most abundant, accounting for 7.9% of the total abundance. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-18 Table 9-9. Dominant infaunal species found in the Mission Bay during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Barleeia sp Mollusca 221 8.6 Exogone lourei Polychaeta 218 8.5 SRE Aphelochaeta sp. Polychaeta 203 7.9 * Values were calculated from the total of all sites assessed. Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Mission Bay were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 9-5. For Mission Bay, the relative ranks were 11 for chemistry, 8 for toxicity, and 1 for benthic community structure. 9.4.1.3 Summary and Conclusions Sediments in Mission Bay were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size): Site 1L-1 in the outer Stratum, and sites 3R-1 and 3L-1 in the inner stratum. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven of the nine metals assessed were found in Mission Bay sediments. Of these, arsenic, copper, lead and zinc all exceeded their ERLs. The mean ERM- Q for Mission Bay was the highest of any embayment assessed in the ABLM Program. No ERMs were exceeded. There were no PAHs, PCBs, or pesticides found above the detection limit in Mission Bay during the 2004 program. In contrast to the sediment chemistry results, the percent survival of the test organisms exposed to Mission Bay sediments was not significantly different from that of the Control, suggesting that the sediments were not toxic to the test organisms. The benthic community indices suggested that the biotic community in the Mission Bay had a rank of 1 (where1 represents the lowest combined index score and 12 the highest). The infaunal community was dominated by a genus of barley snail, and polychaete worms. The relative ranks for Mission Bay compared to the other embayments of the ABLM Program were 11 for chemistry, 8 for toxicity and 1 for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Mission Bay had an overall rank of eight. During the 2003 ABLM program the Lagoon had an overall rank of five. An increase in overall ranking indicates a decrease in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. Relative rankings for sediment in Mission Bay 0 2 4 6 8 10 12 Chemistry Toxicity Benthos RankingFigure 9-5. Relative rankings for sediment in Mission Bay. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-19 9.5 WMA Assessment The Mission Bay watershed management area was assessed using data from both dry and wet weather monitoring efforts. One mass loading station located on Tecolote Creek collected chemistry and toxicity data during storm events. Chemistry data was collected from five dry weather monitoring sites upstream of the MLS. Two bioassessment sites were evaluated and scored on the Index of Biotic Integrity. The watershed management area assessment methods presented in Section 3.4 of this report were applied to these data to determine constituents of concern (COC) and develop a water quality objective (WQO) exceedance frequency for each of these COC. Water quality objective exceedances in wet and dry weather and the IBI scores of the bioassessment sites are summarized in Table 9-10. Using the evaluation criteria discussed in Section 3, constituents were assigned zero, one, two, or three diamonds depending on their frequency of occurrence. Data from this table were evaluated for this watershed using the triad decision matrix (Table 9-11). Four constituents had a high frequency of occurrence and received three diamonds. These constituents include: • Turbidity, • Fecal Coliform, • Total Coliform, and • Enterococcus, Fecal coliform received three diamonds based on Criterion No. 1 because WQO were exceeded in 83% of wet weather samples. Total coliform received three diamonds based on Criterion No. 2 because six of the last consecutive storm samples exceeded WQOs, and turbidity and enterococcus received three diamonds based on Criterion No. 3, as both had wet weather exceedances between 50 and 80% plus a dry weather exceedance in the last year. No constituents received three diamonds during the 2003-2004 monitoring year. Two constituents were identified as having a medium frequency of occurrence and received two diamonds based on Criterion No. 5. These constituents include: • Total suspended solids • Diazinon Although Diazinon had zero wet or dry weather exceedances in the 2004-2005 sampling season, it still received two diamonds (medium frequency of occurrence) due to its cumulative exceedance frequency of 58% during wet weather. Diazinon received the same ranking the previous year. Total suspended solids increased to two diamonds during the 2004-2005 monitoring year due to its 58% MLS exceedance frequency. During the 2003-2004 monitoring year, total suspended solids received a one diamond ranking due to wet weather exceedances. Three constituents had a low frequency of occurrence and received one diamond. These constituents include: • pH • COD • Orthophosphate Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-20 Table 9-10. Constituent exceedances in the Mission Bay WMA. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO Or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters pH 0 0 0 0 0 0 0 0 0 0 1 20 ♦ 8 BOD 0 0 0 0 1 33 0 0 1 8 NA NA - - COD 1 33 1 33 2 67 1 33 5 42 NA NA ♦ 9 Total Suspended Solids 0 0 3 100 1 33 3 100 7 58 NA NA ♦♦ 5 Turbidity 1 33 3 100 2 67 3 100 9 75 2 40 ♦♦♦ 3 Nutrients Orthophosphate NA NA NA NA NA NA NA NA NA NA 1 20 ♦ 8 Total Phosphorus 0 0 0 0 0 0 1 33 1 8 NA NA - - Bacteriological Total Coliform 0 0 2 67 3 100 3 100 8 67 1 20 ♦♦♦ 2 Fecal Coliform 2 67 2 67 3 100 3 100 10 83 0 0 ♦♦♦ 1 Enterococcus 0 0 3 100 2 67 3 100 8 67 1 20 ♦♦♦ 3 Pesticides Chlorpyrifos 0 0 1 33 0 0 0 0 1 8 0 0 - - Diazinon 3 100 3 100 1 33 0 0 7 58 0 0 ♦♦ 5 Malathion NA NA 1 33 0 0 0 0 1 8 NA NA - - Total Metals Antimony 0 0 1 33 1 33 0 0 0 0 NA NA - - Copper 0 0 1 33 0 0 1 33 2 17 NA NA - - Zinc 0 0 0 0 0 0 1 33 1 8 NA NA - - Dissolved Metals Copper 0 0 1 33 0 0 0 0 1 8 0 0 - - Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 96-hour 0 0 1 33 0 0 0 0 1 8 NA NA No Ceriodaphnia 7-day survival 1 33 1 33 0 0 0 0 2 17 NA NA No Ceriodaphnia 7-day reproduction 1 33 1 33 1 33 0 0 3 25 NA NA No Selenastrum 96-hour 1 33 0 0 0 0 0 0 1 8 NA NA No Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? Rose Creek (DS) NA Very Poor Poor Poor Poor NA Tecolote Creek (DS) Very Poor Poor Very Poor Very Poor Very Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-21 Both orthophosphate and pH had a criterion ranking of eight due to dry weather exceedances. Neither constituent was ranked the previous year or had ever been found to exceed WQOs in wet weather. COD received one diamond based on Criterion No. 9 for wet weather exceedances between 25 and 50%, as it did the previous year. In addition to the constituents listed in Table 9-10, several other constituents have been identified as concerns in the Mission Bay watershed because they are listed on the SWRCB 303(d) List. These include indicator bacteria, eutrophication, and lead in Mission Bay, and cadmium, copper, lead, zinc and toxicity in Tecolote Creek. There was no evidence of persistent toxicity associated with wet weather runoff at the MLS. The cumulative IBI ratings for Rose Creek and Tecolote Creek were poor and very poor, suggesting evidence of benthic alteration within the Mission Bay watershed. Figure 9-6 summarizes the average number of water quality exceedances (including constituents that had no exceedances) for six categories of constituents and displays how water quality concerns are changing over time. This stacked bar chart groups constituents as either conventionals, nutrients, bacteria, pesticides, metals, or toxicity. It uses the number of MLS exceedances from values in Table 9-10. Mission Bay Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 9-6. Stacked bar chart of the number of wet weather exceedances of constituent groups in Mission Bay WMA. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-22 For the Tecolote Creek MLS, the overall frequency of WQO exceedances during 2004-2005 was dominated by conventional and bacteriological parameters, with some exceedances of metals and nutrients. The previous three sampling seasons had similar influences, however 2004-2005 was the first year in four years without any pesticide or toxicity exceedances, however it was the first year with nutrient exceedances. Triad Decision Matrix The triad decision matrix combines the occurrence of COC with the toxicity and bioassessment results to draw potential conclusions about the watershed and provide possible actions for future monitoring or assessment. Table 9-11 summarizes the results and lists possible conclusions and actions. Table 9-11. Decision matrix results for the Mission Bay WMA. Based on the results discussed above, the recommended action within this watershed is to continue to monitor for all elements of the program to gather additional data for assessment and long-term trend analysis and to initiate upstream source identification to determine sources of constituents of concern. Although bacteria parameters are not considered in the triad decision matrix because they are not believed to influence toxicity responses in bioassay test organisms, bacteria should be considered a high priority COC due to its persistence over the last three sampling years. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Mission Bay WMA The water quality priority ratings presented in Table 9-12 are based on the methodology presented in the BLTEA report (WESTON, MOE, & LWA 2005) and are presented in the Methods Section 3.4. Constituent groups and stressor groups are given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicate that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on current results presented in this 2004-2005 annual report and data from the following programs: • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Co-permittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303d Listing Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions Persistent exceedances of water quality objectives (high frequency COC identified) No evidence of persistent toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source identification as a high priority. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. 5) TIE would not provide useful information with no evidence of toxicity. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-23 Table 9-12. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Mission Bay WMA Priority Ratings* Constituent Groups Stressor Groups Watersheds/Sub- watersheds Percentage of Total Area Heavy Metals Organics Oil and Grease Sediments Pesticides Nutrients Gross Pollutants Bacteria/ Pathogens Benthic Alterations Toxicity Mission Bay WMA 100% A D D B C B C A B C Scripps HA (906.30) 15% B D D B C D C A A D Miramar HA (906.4) 64% A D D B C A C A B D Tecolote HA (906.5) 21% A D D A B D C A B A Notes: * = Rating Calculated Based on Area Weighted Averages of Score Value from the sub-watershed areas. ** = Priority Level (Highest-A to Lowest-D) The purpose of the BLTEA ratings is to identify water quality priorities within a watershed based on weighted averages of the sub-watershed ratings. Because it is a weighted average, larger sub-watersheds will have a greater influence in the overall watershed rating. Heavy metals and bacteria were the highest priority (A rated) constituents for the Mission Bay WMA followed by sediments, nutrients, and benthic alterations which were given B ratings. All other constituents were given either a C or D rating. The Scripps sub-watershed, which accounts for 15% of the Mission Bay WMA, had high priority (A) ratings for bacteria and benthic alteration. The Miramar sub-watershed, which accounts for 64% of the Mission Bay WMA, had high priority (A) ratings for heavy metals, nutrients, and bacteria. The Tecolote sub-watershed, which accounts for 21% of the Mission Bay WMA, had high priority (A) ratings for heavy metals, sediments, bacteria, and toxicity. A regional evaluation and description of the BLTEA is presented in the Regional Assessment Section 13. The complete tables used to calculate the ratings are presented in Appendix G. Mission Bay WMA SECTION 9 2004-2005 Urban Runoff Monitoring Report 9-24 9.6 Conclusions and Recommendations For the Tecolote Creek sub-watershed, which accounts for approximately 14% of the Mission Bay watershed management area, the primary land uses within the contributing runoff area are residential (43%), and transportation (21%). For the Mission Bay WMA, turbidity, and all three bacterial indicators were identified as high frequency of occurrence COC, TSS and Diazinon were identified as medium frequency of occurrence COC, and ph, COD, and orthophosphate were identified as low frequency of occurrence COC. Third party data collected in 2002 under SWAMP indicated that sulfate, manganese, and toxicity were consistent problems at the Tecolote Creek monitoring station. There was no evidence of persistent toxicity associated with samples collected from the Tecolote Creek MLS. However, the in- stream benthic community was ranked as poor and very poor, suggesting evidence of benthic alteration. In Mission Bay, the final receiving waters for Tecolote Creek, relative rankings were 11 for chemistry, 8 for toxicity and 1 for benthic community structure. Overall, Mission Bay received a ranking of eight compared to other embayments within San Diego County. Mission Bay experienced a decrease in relative quality compared with the 2003 ABLM program. In addition to the WMA assessment findings, the BLTEA ratings found heavy metals and bacteria were the highest priority (A rated) constituents for the Mission Bay WMA followed by sediments, nutrients, and bacteria which were given B ratings. The heavy metals priority rating found in the BLTEA rating was primarily due to the 303(d) listings for metals in the Miramar and Tecolote sub-watersheds even though the WMA assessment did not indicate metals were an overall priority. The information provided from the triad matrix results used in conjunction with the BLTEA ratings can assist the jurisdictions in making informed decisions in developing their WURMP programs. The two reports also allow for an evaluation of where data gaps exist and where efforts should be targeted. Utilizing the BLTEA rating methods for future data evaluations would also allow for long-term BMP effectiveness assessment. Incorporation of additional useable data from other third party sources such as POTWs and non-profit organizations would also help to increase the confidence of the BLTEA ratings and overall WMA assessments. The recommendations for the Mission Bay watershed are to continue monitoring to gather additional data for assessment and long-term trend analysis and to initiate upstream source identification to determine sources of constituents of concern. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-1 10.0 SAN DIEGO RIVER WATERSHED MANAGEMENT AREA 10.1 Monitoring Site Descriptions The San Diego River watershed management area includes the San Diego River watershed (HU 907.00), which is the second largest watershed lying entirely within San Diego County and consists of approximately 277,500 acres (Figure 10-1). It includes four hydrologic areas: Lower San Diego, San Vicente, El Capitan, and Boulder Creek. The watershed is drained by the San Diego River, which discharges into the Pacific Ocean at Ocean Beach. The San Diego River watershed contains the second largest percentage of unincorporated land in San Diego County: 74.7% of the watershed is unincorporated. The remaining areas of the watershed include the Cities of El Cajon, La Mesa, Poway, San Diego, and Santee. Land use within the watershed is primarily undeveloped (58%). Other major uses are residential (18%), and parks and recreation (15%) (SANDAG 2000). Approximately half of the watershed is privately-owned land. The remaining portions are mostly federally-owned with a small percentage of land being state or locally-owned. The San Diego watershed is the most populated in the county containing over 506,000 people, yet has a rather low population density of 1.82 persons per acre. The San Diego River watershed provides many beneficial uses with its many reservoirs, lakes, rivers, and creeks (Table 10-1). The watershed contains the San Diego River, Boulder Creek, El Capitan Reservoir, San Vicente Reservoir, Lake Jennings, Lake Cuyamaca, and Lake Murray. Principal aquifers in the watershed include the Santee/El Monte Basin and the Mission Valley Basin. Famosa Slough lies at the mouth of the San Diego River and provides wetlands habitat. In addition to water resources the watershed contains many parks and open space areas. Mission Trails Regional Park provides nearly 5,800 acres of natural habitat and recreation areas. Table 10-2 presents the water bodies in the San Diego River watershed that have been placed on the SWRCB 303(d) list. Major impacts to the watershed include surface water quality degradation, habitat degradation and loss, sediment, invasive species, eutrophication, and flooding (San Diego County, 2002). Constituents that have been placed on the SWRCB 2002 303(d) list for water bodies throughout the watershed are bacterial indicators, TDS, phosphorus, eutrophication, pH, and dissolved oxygen. The sources of the contaminants include urban runoff, sewage spills, and sand mining (San Diego County 2002). Annual precipitation ranges from 10.5 inches near the coast to nearly 35 inches in the eastern portion of the watershed (Figure 10-1). The San Diego River (SDR) mass loading station is located along a natural channel in San Diego, adjacent to the Fashion Valley Mall. The contributing runoff area consists of over 107,200 acres, which is approximately 39% of the San Diego watershed land area. The major land uses within the contributing runoff area are residential (29%), parks (24%), and undeveloped (21%). The San Diego River drains into the Pacific Ocean. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-2 Figure 10-1. San Diego River Watershed Management Area. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-3 Table 10-1. Beneficial uses within the San Diego River watershed. Beneficial Uses Inland Surface Waters Coastal Waters Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z z z Agricultural Supply z z z Industrial Service Supply z z z Industrial Process Supply z z z Navigation Contact Water Recreation z z z1 Non-Contact Water Recreation z z z Commercial and Sport Fishing z Warm Freshwater Habitat z z Cold Freshwater Habitat z z Estuarine Habitat z Wildlife Habitat z z z Biological Habitats z Rare, Threatened, or Endangered Species z z z Marine Habitat z Migration of Aquatic Organisms z Aquaculture Shellfish Harvesting z Spawning, Reproduction and/or Early Development Hydropower Generation z 1 Shore and boat fishing only. Other REC1 uses prohibited. Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) Table 10-2. Water bodies on the SWRCB 303(d) list in the San Diego River watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor Famosa Slough and Channel Mission San Diego 907.11 Eutrophic Pacific Ocean Shoreline Mission San Diego 907.11 Bacterial Indicators Lower San Diego River Mission San Diego 907.11 Fecal Coliform, Low Dissolved Oxygen, Phosphorus, TDS Forrester Creek Santee 907.12 Fecal Coliform, pH, TDS Source: SWRCB 2003 San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-4 Stream bioassessment monitoring in the San Diego River WMA has occurred at two urban affected sites and one reference site. The upper urban affected monitoring reach is located in lower Mission Trails Park. This site has very good in-stream riffle habitat with complex and stable boulder and cobble, and the riparian zone is undisturbed. Flow is year-round, but can be very low during the dry season in drought years. The lower monitoring reach is located near the Morena Boulevard overpass. Finding suitable riffle habitat in this reach is problematic, as the majority of the river is deep and slow flowing throughout Mission Valley. There is only one high quality riffle with good flow velocity and a rocky substrate. A reference site has been sampled one time on Cedar Creek, south of the town of Julian on Cedar Creek Road. The habitat quality is very good but the stream does not always flow through the dry season, as was the case in October of 2003. Cedar Creek also suffered from very heavy sediment loading after the Cedar Fire of 2003, and is not currently suitable for sampling. 10.2 Storm Water Monitoring Summary Three storm events were monitored at the MLS on San Diego River during 2004-2005. For the 2004- 2005 wet season events, monitoring took place on October 27, 2004 and February 11 and 18, 2005. The results from these storms are discussed in the following section (10.2.1) and presented in Table 10-3. A comparison of these results to previous years is provided in section 10.2.2. 10.2.1 2004-2005 Results Four conventional constituents exceeded water quality objectives during at least one of the three storms monitored in 2004-2005, including fecal coliform, chemical oxygen demand (COD), TSS, and turbidity. Fecal coliform exceeded the WQO during all three storm events monitored during the 2004-2005 wet weather season. Fecal coliform is the only bacterial indicator with a water quality objective for wet weather monitoring. Turbidity exceeded the WQO during the October 27, 2004 and February 18, 2005 storm events. Total suspended solids exceeded the WQO during the October 27, 2004 storm and COD exceeded the WQO during the February 11, 2005 storm event. None of the objectives for pesticides, hardness, total metals, and dissolved metals were exceeded in the 2004-2005 season at the San Diego River mass loading station. No toxicity was observed for any samples collected from San Diego River during 2004-2005 (See Section 3.1.6.2 for details on toxicity testing). All the bioassay test results had NOEC values of 100%. Table 10-3. Analytes measured at the San Diego River mass loading station.11/29/01 2/17/02 3/17/02 11/8/02 12/16/02 2/11/03 11/12/03 2/3/04 3/2/04 10/27/04 02/11/05 02/18/05Electrical Conductivity umhos/cm 1680 2230 2270 1568 811 15502470 1546 995 560 126 747Oil and Grease mg/L 15 USEPA Multi-Sector General Permit <1 4 <1 10.70 <1.00 2.39 4.83 <1 <1 <1 <1 <1 0% 0.14pH pH Units 6.5-8.5 Basin Plan 7.3 7.6 7.5 7.68 7.64 7.61 7.48 7.70 7.26 7.16 7.63 7.20 0% 0.00Enterococci MPN/100 mL 80 2,200 170 17,000 13,000 7,000 11,000 23,000 358 22,000 2,300 22,000Fecal Coliform MPN/100 mL 400 Basin Plan 13030,000170110,000 17,000 5,000 13,000 2,300 5005,000 800 1,30083% 38.58Total Coliform MPN/100 mL 2,300 80,000 3,000 220,000 50,000 23,000 50,000 28,000 11,000 300,000 30,000 50,000Ammonia As N mg/L 0.9 0.7 0.2 0.34 0.13 0.19 <0.1 <0.1 1.8 0.38 0.28 0.95Un-ionized Ammonia as Nμg/L 25 (a) Basin Plan 5.11 1.5 2.04 0.48 0.62 7.90 0.2 0.5 8.2 0% 0.12Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit 1258.83.4 4.73 <2.0 20.7 8.4445.22.94 4.22 3.68 3.39 17% 0.47Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit 2815454 71 48 63 83 67 52 9828356 17% 0.73Dissolved Organic Carbon mg/L 6.80 8.68 10.70 16.6 4.26 5.57 33.2 2.94 5.62Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.3 0.03 0.12 0.19 0.24 0.19 0.41 0.13 0.15 0.44 <0.05 0.32 0% 0.11Nitrate As N mg/L 10 Basin Plan 0.9 0.8 0.3 0.67 0.56 0.57 0.5 0.2 0.63 0.37 0.66 1.01 0% 0.06Nitrite As N mg/L 1 Basin Plan 0.12 0.07 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0% 0.04Surfactants (MBAS) mg/L 0.5 Basin Plan <0.50.6<0.5 <0.1 <0.1 0.2 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 8% 0.48Total Dissolved Solids mg/L 1000 Basin Plan by watershed 869 691 7961260676 8961540 1120491 594 756 490 25% 0.85Total Kjeldahl Nitrogen mg/L 2.7 2.9 1.7 1.6 1.2 1.5 1.4 2.8 2 2.3 <0.5 23.3Total Organic Carbon mg/L 18.3 39.8 12.4 16.7 11.7 11.5 62 9.61 9.6Total Phosphorus mg/L 2 USEPA Multi-Sector General Permit 1.21 0.4 0.28 0.57 1.01 0.33 0.34 0.23 0.35 0.85 0.28 0.44 0% 0.26Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit <20 24 20 4321266 34 <20 2147750 61 17% 0.86Turbidity NTU 20 Basin Plan 8.6 15.3 13.140.7 104 34.519.931.2 22.423414.530.958% 2.37Chlorpyrifosμg/L 0.02 CA Dept. of Fish & Game <0.03* <0.03*0.03 0.043 0.051 0.048<0.01 <0.01 <0.01 <0.01 <0.01 <0.0133% 0.97Diazinonμg/L 0.08 CA Dept. of Fish & Game0.21 0.100.08 0.051 0.051 0.038<0.01 <0.01 <0.01 <0.01 0.038 <0.0117% 0.62Malathionμg/L 0.43 CA Dept. of Fish & Game <0.10 <0.10 <0.10<0.01 <0.01 <0.01 <0.01 <0.01 <0.010% 0.05Total Hardness mg CaCO3/L 429 399 490 545 331 483759 476 206 201 364 251Antimony mg/L 0.006 Basin Plan <0.002 0.003 <0.002 <0.002 0.0060.007<0.005 <0.005 <0.005 <0.005 <0.005 <0.0058% 0.47Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan 0.003 0.002 0.005 0.005 0.008 0.0040.005 0.006 0.003 0.006 0.006 <0.0020% 0.09Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.03Chromium mg/L (b) CTR (Cr VI) 0.005 <0.005 0.007 <0.005 0.02 0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.00Copper mg/L (b) 40 CFR 131 0.007 0.028 0.011 0.009 0.021 0.0170.008 0.013 0.006 0.025 0.006 0.0060% 0.29Lead mg/L (b) 40 CFR 131 0.003 0.004 0.009 0.007 0.035 0.0110.004 0.006 0.005 0.060 0.005 0.004Nickel mg/L (b)/0.1 40 CFR 131/ Basin Plan 0.004 0.005 0.004 0.007 0.005 0.0050.005 0.003 <0.002 0.006 0.003 0.0020% 0.00Selenium mg/L 0.02 40 CFR 131 <0.002 0.002 <0.002 <0.004 <0.004 <0.004<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.10Zinc mg/L (b) 40 CFR 131 0.029 0.112 0.067 0.031 0.118 0.0770.046 0.053 0.026 0.213 0.033 0.0320% 0.22Antimony mg/L (e) 40 CFR 131 <0.002 <0.002 <0.002 0.002 0.007 0.002<0.005 <0.005 <0.005 <0.005 <0.005 <0.005Arsenic mg/L 0.34 (c) 40 CFR 131 0.002 <0.001 0.002 0.004 0.003 0.0030.004 0.003 0.002 <0.002 <0.002 <0.0020% 0.00Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.001 <0.001 <0.001 <0.0010% 0.03Chromium mg/L (b) 40 CFR 131 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.00Copper mg/L (b) 40 CFR 131 0.006 0.015 <0.005 0.005 0.006 0.015<0.005 0.005 <0.005 <0.005 <0.005 0.0050% 0.12Lead mg/L (b) 40 CFR 131 0.002 <0.002 <0.002 0.006 0.002 <0.002<0.002 <0.002 <0.002 <0.002 <0.002 <0.002Nickel mg/L (b) 40 CFR 131 0.003 0.005 0.002 0.006 <0.002 0.0030.003 0.003 <0.002 0.003 0.002 0.0020% 0.00Selenium mg/L 0.02 (d) 40 CFR 131 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004<0.005 <0.005 <0.005 <0.005 <0.005 <0.0050% 0.10Zinc mg/L (b) 40 CFR 131 0.022 0.084 <0.020 0.026 0.037 0.070<0.02 <0.02 <0.02 <0.02 <0.02 <0.020% 0.072001-02BacteriologicalWet ChemistryPesticidesANALYTE UNITS WQO2002-03Hardness2003-04SOURCETotal MetalsFrequency Above WQOMean Ratio to WQO2004-05Dissolved MetalsGeneral / Physical / Organic Table 10-3. Analytes measured at the San Diego River mass loading station.11/29/01 2/17/02 3/17/02 11/8/02 12/16/02 2/11/03 11/12/03 2/3/04 3/2/04 10/27/04 02/11/05 02/18/052001-02ANALYTE UNITS WQO2002-03 2003-04SOURCEFrequency Above WQOMean Ratio to WQO2004-05Ceriodaphnia 96-hr LC50 (%) 100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 0% 0.00Ceriodaphnia 7-day survival NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Ceriodaphnia 7-day reproduction NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Hyalella 96-hr NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Selenastrum 96-hr NOEC (%) 100 10025100 100 100 100 100 100 100 100 100 100 8% 0.33SourcesUSEPA Federal Register Document 40 CFR Part 131, May 18, 2000.USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-SectorGeneral Permit for Industrial Activities,65 Federal Register (FR) 64746, Final Reissuance,October 30, 2000. Table 3 - Parameter benchmark values.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.* Indicates detection limit exceeds water quality objective.Shaded text – exceeds water quality objective.(e) USEPA has not published an aquatic life criterion value.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.ToxicityBlank spaces have been verified and no data is available due to changes in the monitoring program. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-7 10.2.2 Relationships/Analyses During the last four years of monitoring, there have been occasional WQO exceedances from BOD, COD, MBAS, TDS, TSS, and total antimony. For the constituents that exceeded water quality objectives during multiple storm events, there is no pattern or trend to be discerned. Turbidity exceeded the WQO during seven of the 12 storm events (58%). Fecal coliform consistently has exceeded the WQO in 10 out of 12 storms (83%). Total coliform and enterococcus also consistently had elevated levels. Nutrients have never exceeded water quality objectives during any of the 12 storm events monitored. Chlorpyrifos and Diazinon were not detected during any storm events monitored during the 2003-2004 and 2004-2005 monitoring years. However, this contrasts with the previous two years in which Chlorpyrifos and Diazinon were consistently detected and frequently exceeded the water quality objective. Analysis of the results suggests that there is a significant downward trend in Diazinon (R2=0.58) concentrations. Malathion has never been detected at the MLS during wet weather events (since monitoring began in Fall 2002). During the last three years of monitoring, only one metal (Antimony) has exceeded the water quality objective. Total and dissolved metals have persistently been below the water quality objectives. In order to illustrate the magnitude of the water quality exceedances for 2004-2005, the ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern. The results are shown in Figure 10-2. The largest single exceedance was for fecal coliform, which exceeded the WQO by 12.5 times during the October 27, 2004 storm. There was also a noticeable single exceedance for TSS, which exceeded the WQO by 4.7 times during the October 27, 2004 storm. The average magnitude of water quality exceedances was also determined for each constituent by calculating the mean ratio of water quality results to the WQOs from all storm events from October 2001 through April 2004. Mean ratios are illustrated in Figure 10-2. The largest average exceedance for the period of record was for fecal coliform, which exceeded the WQO by nearly 50 times. The next largest average exceedance was for turbidity, which exceeded the WQO approximately 1.6 times. In addition to the wet weather monitoring discussed above, there are 54 sites in the San Diego River WMA where water quality is monitored during dry weather. Of these, 49 sites are located upstream of the mass loading station on San Diego River. Only those sites that are located upstream of the MLS and downstream of any reservoir are included in the evaluation, therefore approximately eight dry weather sites within the San Diego River WMA are not included in the dry weather results (See Section 3.4 for details on dry weather sampling). San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-8 TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 2040 Ratio to WQOMean Ratio (Oct 01 to Apr 04) 10/27/04 2/11/05 2/18/05 Above WQO Figure 10-2. San Diego River water quality ratios. Table 10-4 shows exceedances and ratios of exceedances for constituents that were measured during the 2004 dry weather monitoring program. During dry weather sampling there were exceedances of action levels at the monitoring sites located above the mass loading station for pH, turbidity, nitrate, ammonia, phosphorus, MBAS, Diazinon, total and fecal coliform, and enterococcus. Of these, turbidity and total coliform had average ratios of exceedance much greater than one. A map for the WMA showing DWS exceedances is found in Figure 10-3. Pie symbols appear at dry weather stations that have had water quality exceedances. The colored slices of the pie show the different constituent groups that contributed to the exceedances. The constituents that Table 10-4. San Diego River WMA 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* St. Dev. Ratio of Exceedance pH 3 49 0.13 0.23 Turbidity 8 45 5.61 33.3 Nitrate 2 46 0.32 0.42 Ammonia 7 46 1.00 3.76 Phosphorus 6 46 0.42 0.67 MBAS 1 48 0.25 0.15 Diazinon 2 41 0.34 1.29 Total Coliform 20 49 2.72 5.31 Fecal Coliform 5 49 0.47 1.27 Enterococcus 12 49 0.63 0.78 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-9 exceeded objectives during the 2004-2005 wet weather season and the 2004 dry weather monitoring program were fecal coliform and turbidity. 10.2.3 Third Party Data Third party data was provided by Padre Dam Municipal Water District (Padre Dam) and is presented in Table 13-23 of the Regional Assessments (Section 13). Monthly monitoring results collected from January 2004 through December 2004 at six locations upstream from the MLS were evaluated and compared to wet weather and dry weather sample results. Parameter groups that were included in the Padre Dam data include nutrients, conventionals, and microbiology. The sample results from Padre Dam represent a snapshot of the water quality conditions upstream of the MLS throughout the year. For parameters on the 303(d) list for the lower San Diego River, results from Padre Dam exceeded the Basin Plan WQO for TDS in 52 of 72 samples; turbidity exceeded the WQO in 8 of 72 samples; dissolved oxygen exceeded the WQO in 33 of 72 samples, fecal coliform exceeded the WQO in 17 of 72 samples, and E. coli exceeded the WQO in 20 out of 72 samples. Although the lower San Diego River is listed on the 303(d) list for phosphorus, there were no water quality objective exceedances of phosphorus for 2004 in the Padre Dam samples. Parameters that exceeded water quality objectives in Padre Dam data, dry weather data, and wet weather MLS data include TDS, turbidity, fecal coliform, and total coliform. The Padre Dam data for TDS confirms previous work that shows that storm water runoff concentrations of TDS during wet weather events are considerably lower than during dry weather periods. TDS concentrations can be influenced by groundwater inputs and frequently exceed the Basin Plan surface water quality objective within the San Diego River WMA. TDS concentrations frequently exceed water quality objectives and have historically exceeded water quality objectives in this WMA based on natural variability. This condition may have been exacerbated by the increased importation of Colorado River water (San Diego Regional 303(d) Workgroup 2002). 10.2.4 TIEs TIE testing was not performed on San Diego River samples. This mass loading station has not been identified as a TIE candidate site based upon the Triad Decision Matrix. Toxicity was not observed in any of the three storm events during the 2004-2005 storm season. 10.2.5 Summary and Conclusions Turbidity and elevated levels of bacterial indicators, specifically fecal coliform, appear to be the most consistent, primary water quality concerns within the watershed. Based on the period of record, there appears to be a significant downward trend in Diazinon concentrations at the MLS. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-10 Figure 10-3. San Diego River WMA dry weather exceedance map. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-11 10.3 Stream Bioassessment Stream bioassessment in the San Diego River WMA included two urban affected monitoring sites. The upstream site was located in Mission Trails Regional Park, and the downstream site was located upstream of the Morena Blvd. overcrossing in Mission Valley. 10.3.1 Results and Discussion San Diego River in Mission Trails Regional Park: SDR-MT The Mission Trails monitoring site had a benthic community with an Index of Biotic Integrity rating of Poor for the October 2004 survey and Very Poor for the May 2005 survey (Table 10-5) (See Section 3.2 for details on the sampling approach). Taxa richness was moderate to low, with 23 and 14 different taxa collected in the October 2004 and May 2005 surveys, respectively. Two and three different EPT taxa were collected in the October and May surveys. There were no organisms collected that are highly intolerant to impairment, and the percent tolerant comprised 33% and 2% of the community in October 2004 and May 2005, respectively. The physical habitat of the monitoring reach was optimal. The substrate had very complex cobble, boulder, and tree root niche space suitable for colonization. The willow riparian zone was mostly undisturbed and the relatively steep gradient of the river made for good current velocity. Water quality was variable, with very high specific conductance in October and relatively low values in May. Specific conductance values were 6.018 mS/cm in October and 1.691 mS/cm in May. Values for pH were 7.5 and 8.2 for the October and May surveys, respectively. The benthic community was seasonally variable. In October, dominance by a single taxon was low and Chironomid midges; the biting midge, Dasyhelea; the caddisfly, Hydroptila; the clam, Corbicula fluminea; and the damselfly, Argia, were the most abundant (Table 10-6). In May, the community was dominated by the black fly, Simulium, and the mayflies, Baetis and Fallceon quilleri. Percent collector filterers plus collector gatherers increased from 53% of the community in October to 97% in May. The San Diego River mass loading station was too spatially disconnected from the Mission Trails site to correlate any of the storm water information with the benthic community. San Diego River at Morena Blvd.: SDR-1 The Mission Valley monitoring site had a benthic community with an Index of Biotic Integrity rating of Very Poor for both the October 2004 and May 2005 surveys (Table 10-5). The IBI scores were eight and four, which was an increase from the 2003-2004 surveys when the site was the lowest rated site in the county. Taxa richness was about double the previous years’ surveys, with 17 and 12 different taxa collected in October and May, respectively. One EPT taxon was collected in both surveys. There were no organisms collected that are highly intolerant to impairment, and the percent tolerant taxa comprised 42% and 15% of the community in October and May, respectively. The physical habitat of the monitoring reach was sub-optimal to near marginal. The San Diego River has a very low gradient through all of Mission Valley, although the riffles sampled were some of the only places where current velocity is greater than 1 ft/sec. and cobble was present. Two of the sample transects were dominated by cobble and small boulder, and one was primarily root mat. Specific conductance was relatively high to moderate, but lower than at the Mission Trails site. Values were San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-12 3.825 ms/cm in October 2004 and 1.547 ms/cm in May 2005. Values for pH were 7.7 and 7.4 for the October and May surveys, respectively. Table 10-5. Selected Biological Metrics and Physical Measures of the San Diego River WMA. San Diego River Watershed Management Area San Diego River in Mission Trails Regional Park (SDR-MT) San Diego River Upstream of Morena Blvd. (SDR-1) Survey Oct-04 May-05 Oct-04 May-05 Index of Biotic Integrity/ Qualitative Rating 20 Poor 6 Very Poor 8 Very Poor 4 Very Poor Metrics Taxa Richness 23 14 17 12 EPT Taxa (mayflies, stoneflies, and caddisflies) 2 3 1 1 % Intolerant Taxa 0% 0% 0% 0% % Tolerant Taxa 33% 2% 42% 15% Average Tolerance Value 6.8 5.6 6.7 6.1 % Collector Filterers +Collector Gatherers 53% 97% 67% 83% Physical Measures Elevation 180 10 Physical Habitat Score 158 181 120 144 Riffle Velocity (ft/sec) 0.8 1.6 2.3 1.8 Substrate Composition Silt 13% Sand 3% 10% 37% Gravel 2% 7% 10% 6% Cobble 30% 72% 40% 35% Boulder 27% 18% 7% 22% Roots 26% 33% Bedrock/Solid 2% Water Quality Temperature ºC 19.4 18.8 21.4 20.8 pH 7.5 8.2 7.7 7.4 Specific Conductance (ms/cm) 6.018 1.691 3.825 1.547 Relative Chlorophyll (μg/L) 2.9 4.9 5.3 8.2 San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-13 Table 10-6. San Diego River WMA Community Summary. Taxon Common Name Percent Composition Tolerance Value Functional Feeding Group Chironomidae non-biting midges 17% 6 Collector Gatherer/Filterer Dasyhelea biting midge 12% 6 Collector Gatherer Hydroptila microcaddisfly 10% 6 Piercer Herbivore Corbicula fluminea clam 10% 10 Collector Filterer Oct-04 Argia dancer damselfly 8% 7 Predator Simulium black fly 57% 6 Collector Filterer Baetis minnow mayfly 21% 5 Collector Gatherer Fallceon quilleri minnow mayfly 11% 4 Collector Gatherer Chironomidae non-biting midges 6% 6 Collector Gatherer/Filterer San Diego River in Mission Trails Regional Park (SDR-MT) May-05 Oligochaeta earth worm 2% 5 Collector Gatherer Simulium black fly 31% 6 Collector Filterer Turbellaria flatworm 14% 4 Predator Hyalella amphipod 13% 8 Collector Gatherer Corbicula fluminea clam 11% 10 Collector Filterer Oct-04 Prostoma tongue worm 10% 8 Predator Simulium black fly 52% 6 Collector Filterer Hydra hydra 15% 5 Predator Chironomidae non-biting midges 10% 6 Collector Gatherer/Filterer Hyalella amphipod 10% 8 Collector Gatherer San Diego River Upstream of Morena Blvd. (SDR-1) May-05 Oligochaeta earth worm 4% 5 Collector Gatherer The benthic community was dominated by the the black fly, Simulium, in both surveys, but the community was otherwise variable (Table 10-6). In the October survey, flatworms, the amphipod, Hyalella, and the clam, Corbicula fluminea, were abundant. In the May survey, Hydra, Chironomid midges and Hyalella were abundant. The most significant organism collected was the sensitive caddisfly, Oxyethira, in October, which comprised two percent of the community. The amphipod, Americorophium, typically an estuarine species that likely colonizes the site from farther downstream, was much less abundant than in previous surveys (MEC-Weston 2005). This may have been due to the higher freshwater flows from the heavy winter rains. The San Diego River mass loading station was located approximately one mile upstream of the bioassessment station and water quality measures may be correlated with the site. Constituents of concern identified during storm water sampling that would have a negative impact on the biological community included total suspended solids and turbidity (Table 10-3). Toxicity to Ceriodaphnia and Hyalella from storm water was not detected in 2004-2005. Total dissolved solids and metal concentrations were below exceedance levels, but were present in high enough concentrations to have a probable cumulative impact on sensitive organisms. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-14 10.3.2 Summary and Conclusions The San Diego River WMA was sampled at two monitoring sites on San Diego River, one in Mission Trails Regional Park, and one near Morena Blvd. in Mission Valley. The Mission Trails site had an Index of Biotic Integrity rating of Poor and Very Poor, and the Mission Valley site had an IBI rating of Very Poor. The IBI score of the Mission Valley site increased substantially from the previous years surveys, and relatively high numbers of a sensitive caddisfly were collected in October 2004. 10.4 Ambient Bay and Lagoon Monitoring No sampling was performed at the mouth of the San Diego River as part of the Ambient Bay and Lagoon Monitoring program. 10.5 WMA Assessment The San Diego River Watershed Management Area was assessed utilizing chemistry and toxicity data collected during storm events from a single MLS, chemistry data collected from 49 dry weather monitoring sites upstream of the MLS, six locations from third party data provided by Padre Dam Municipal Water District, and IBI scores generated at two bioassessment sites. Third party data sample results provided by Padre Dam Municipal Water District were collected from six locations on a monthly basis from January through December, 2004 and were located upstream of the MLS. The data from Padre Dam was incorporated in to the dry weather data for the triad assessment. The watershed management area assessment methods presented in Section 3.4 were applied to these data to determine which constituents were of concern and to develop a high, medium, or low frequency of occurrence for these constituents. The results of this assessment are presented in Table 10-7. For the San Diego watershed, four constituents were found to have a high frequency of occurrence and are listed below. All constituents received three diamonds based on Criterion No. 3, with the exception of fecal coliform which received three diamonds based on Criterion No. 1. These constituents include: • Fecal Coliform • Total Coliform • Enterococcus • Turbidity One constituent was found to have a medium frequency of occurrence and received two diamonds based on Criterion No. 7. This constituent was: • Total dissolved solids Two constituents, ammonia and orthophosphate, were found to have a low frequency of occurrence (one diamond) based on dry weather data alone. However, after combining third party data from Padre Dam in the evaluation, these constituents were no longer identified as COCs. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-15 Table 10-7. Constituent exceedances in the San Diego River WMA. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters pH 0 0 0 0 0 0 0 0 0 0 3 4 - - BOD 1 33 0 0 1 33 0 0 2 17 NA NA - - COD 1 33 0 0 0 0 1 33 2 17 NA NA - - Surfactants (MBAS) 1 33 0 0 0 0 0 0 1 8 1 2 - - Total Dissolved Solids 0 0 1 33 2 67 0 0 3 25 52 72 ♦♦ 7 Total Suspended Solids 0 0 1 33 0 0 1 33 2 17 NA NA - - Turbidity 0 0 3 100 2 67 2 67 7 58 16 13 ♦♦♦ 3 Nutrients Ammonia 0 0 0 0 0 0 0 0 0 0 7 6 - - Orthophosphate NA NA NA NA NA NA NA NA NA NA 6 5 - - Nitrate as N 0 0 0 0 0 0 0 0 0 0 2 2 - - Bacteriological Total Coliform 1 33 2 67 1 33 2 67 6 50 23 19 ♦♦♦ 3 Fecal Coliform 1 33 3 100 3 100 3 100 10 83 20 17 ♦♦♦ 1 Enterococcus 0 0 2 67 2 67 2 67 6 50 12 24 ♦♦♦ 3 Pesticides Chlorpyrifos 1 33 3 100 0 0 0 0 4 33 0 0 - - Diazinon 2 67 0 0 0 0 0 0 2 17 2 5 - - Total Metals Antimony 0 0 1 33 0 0 0 0 1 8 NA NA - - Dissolved Metals Copper 0 0 0 0 0 0 0 0 0 0 3 6 - - Toxicity EVIDENCE OF PERSISTENT TOXICITY? Selenastrum 96-hour 1 33 0 0 0 0 0 0 1 8 NA NA No Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? San Diego River, at Mission Trails Park Poor Poor Poor Very Poor Poor NA San Diego River, at Mission Valley (DS) Very Poor Very Poor Very Poor Very Poor Very Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS Although the watershed assessment process did not indicate they were a COC, dissolved oxygen and phosphorus are considered potential contaminants of concern due to their listing on the 303(d) list for the lower San Diego River. Dissolved oxygen exceeded the water quality objective in 46% of the samples from data provided by Padre Dam. Other water bodies within the San Diego River watershed are 303(d) listed for constituents and conditions such as eutrophication at the Famosa Slough and Channel. Eutrophic conditions are indicative of elevated nutrient levels, which were not supported by San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-16 the WMA assessment methodology in the San Diego River MLS, but may occur in localized site specific areas. Toxicity tests conducted on Selenastrum showed evidence of toxicity in one of the 12 tests conducted since 2001. No other test organism showed evidence of toxicity. Therefore, there is no evidence of persistent toxicity in the San Diego River watershed. IBI scores resulting from bioassessment monitoring on the San Diego River consistently indicated a rating of Very Poor at the Mission Valley bioassessment site. The Mission Trails Park site received a rating of poor the first three years of monitoring and very poor the last year of monitoring. Therefore, there are indications of benthic alteration within the San Diego River watershed. Figure 10-4 summarizes the number of water quality exceedances for six categories of constituents. Categories include conventionals, nutrients, bacteria, pesticides, metals and toxicity. The stacked bars were developed using number of exceedances from values of MLS results in Table 10-7 for each constituent category. The overall number of water quality objectives exceedances at the San Diego River MLS has remained low during the last four monitoring seasons with bacteriological and conventional parameters being the only COC during the past two monitoring seasons. San Diego River Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 10-4. Stacked bar chart of the number of wet weather exceedances of constituent groups in San Diego River. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-17 Evaluation of scatterplots presented in Appendix C indicate that concentrations of TDS, which is a medium frequency COC, sporadically exceeded the water quality objective and does not appear to be decreasing. While conductivity can be used to estimate TDS values, it is notable that there is a statistically significant decreasing trend in conductivity (R2=0.67) over the past four monitoring seasons. A statistically significant decreasing trend for Diazinon (R2=0.58) was also evident with no exceedances of the WQO since the 2001-2002 monitoring season. There were no statistically significant increasing trends evident for any of the parameters monitored at the San Diego River MLS. Triad Decision Matrix The triad decision matrix combines the occurrence of COC with the toxicity and bioassessment results to determine possible conclusions about the watershed and provide possible actions for future monitoring or assessment. Table 10-8 summarizes these results and lists possible conclusions and actions. Table 10-8. Decision matrix results for San Diego River WMA. Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions Persistent exceedances of water quality objectives (high frequency COC identified) No evidence of persistent toxicity Indications of alteration Test organisms not sensitive to problem pollutants Benthic impact due to habitat disturbance, not toxicity 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source identification as a high priority. 3) Consider whether different or additional test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. 5) TIE would not provide useful information with no evidence of toxicity. Based on the triad decision matrix, persistent exceedances of turbidity, no evidence of persistent toxicity, and evidence of benthic alteration, it is recommended to investigate possible upstream sources that may cause increased turbidity. It is possible that turbidity exceedances were elevated due to the excessive rainfall experienced during the 2004-2005 monitoring season. The increase in turbidity exceedances of the dry weather action levels from 2003 to 2004 also supports the need for increased attention to this parameter. It is also recommended to continue monitoring to gather long-term trend information and to consider the potential role of physical habitat disturbance. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the San Diego River WMA The water quality priority ratings presented in Table 10-9 are based on the methodology presented in the BLTEA report (WESTON, MOE, & LWA 2005) and are presented in the Methods Section 3.4. Constituent groups and stressor groups are given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicate that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on current results presented in this 2004-2005 annual report and data from the following programs: San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-18 • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Co-permittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303d Listing Table 10-9. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the San Diego River WMA Priority Ratings* Constituent Groups Stressor Groups Watersheds/Sub- watersheds Percentage of Total Area Heavy Metals Organics Oil and Grease Sediments Pesticides Nutrients Gross Pollutants Bacteria/ Pathogens Benthic Alterations Toxicity San Diego River WMA 100% D D D A B C C A A D Lower San Diego HA (907.10) 40% D D D A B A A A A D San Vicente HA (907.20) 17% D D D B B D D B B D El Capitan HA (907.30) 20% D D D B A D D B B D Boulder Creek HA (907.40) 23% D D D B B D D B B D Notes: * = Rating Calculated Based on Area Weighted Averages of Score Value from the sub-watershed areas. ** = Priority Level (Highest-A to Lowest-D) The purpose of the BLTEA ratings is to identify water quality priorities within a watershed based on weighted averages of the sub-watershed ratings. Because it is a weighted average, larger sub-watersheds will have a greater influence in the overall watershed rating. Sediments, bacteria, and benthic alteration were the highest priority (A rated) constituents for the San Diego River WMA followed by pesticides which was given a B rating. All other constituents were given either a C or D rating. The Lower San Diego sub-watershed, which accounts for 40% of the San Diego River WMA, had high priority (A) ratings for sediments, nutrients, gross pollutants, bacteria, and benthic alteration. The El Capitan sub-watershed, which accounts for 20% of the San Diego River WMA, had a high priority (A) rating only for pesticides. The San Vicente sub-watershed, which accounts for 17% of the San Diego River WMA, and the Boulder Creek sub-watershed, which accounts for 23% of the San Diego River WMA, each had only B priority ratings for sediments, pesticides, bacteria, and benthic alteration. A regional evaluation and description of the BLTEA is presented in the Regional Assessment Section 13. The complete tables used to calculate the ratings are presented in Appendix G. San Diego River WMA SECTION 10 2004-2005 Urban Runoff Monitoring Report 10-19 10.6 Conclusions and Recommendations The San Diego River watershed is the second largest watershed in San Diego County. The contributing runoff area to the MLS is approximately 39% of the San Diego watershed land area. The major land uses within the contributing runoff area are residential (29%), parks (24%), and undeveloped (21%). For the San Diego River WMA, turbidity and all three bacterial indicators were identified as high frequency of occurrence COC followed by TDS, which was identified as a medium frequency of occurrence COC. TDS during wet weather monitoring and monthly monitoring within the watershed by Padre Dam showed a medium frequency of occurrence but appears to be related to groundwater influences and local conditions. As noted in Section 10.2.3, the TDS water quality objective may not accurately reflect the natural conditions of the San Diego River WMA. Dissolved oxygen in samples collected by Padre Dam exceeded the Basin Plan water quality objective 46% of the time. Although ammonia and orthophosphate in dry weather data may indicate localized issues within the WMA, the evaluation and combination of Padre Dam data in the assessment process suggests that on a regional scale these constituents do not frequently exceed water quality objectives. The occurrence of these constituents may be a result of numerous activities or sources. The stream habitat quality was rated Poor in Mission Trails, a large open recreation space, and Very Poor in Mission Valley, a highly urbanized residential and commercial corridor. The Very Poor rating in Mission Valley may be a result of physical disturbances to habitat, insecticides or other COC that are not analyzed for in this program, or algal growth observed and measured as chlorophyll within the stream. In addition to the WMA assessment findings, the BLTEA ratings found sediments, bacteria, and benthic alteration were the highest priority (A rated) constituents for the San Diego River WMA followed by pesticides which was given a B rating. The information provided from the triad matrix results used in conjunction with the BLTEA ratings can assist the jurisdictions in making informed decisions in developing their WURMP programs. The two reports also allow for an evaluation of where data gaps exist and where efforts should be targeted. Utilizing the BLTEA rating methods for future data evaluations would also allow for long-term BMP effectiveness assessment. Incorporation of additional useable data from other third party sources such as POTWs and non-profit organizations would also help to increase the confidence of the BLTEA ratings and overall WMA assessments. The recommendations for the San Diego River watershed are to continue monitoring to gather long- term trend information. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-1 11.0 SAN DIEGO BAY WATERSHED MANAGEMENT AREA 11.1 Monitoring Site Descriptions The San Diego Bay watershed management area consists of three major watersheds: Pueblo San Diego watershed (HU 908.00), Sweetwater watershed (HU 909.00), and Otay watershed (HU 910.00). The entire San Diego Bay WMA covers over 888,400 acres (Coastal Conservancy 2001) (Figure 11-1). Major water bodies include San Diego Bay, Otay River, Sweetwater River, Chollas Creek, and Paradise Creek. San Diego Bay is the largest estuary in San Diego County and has been extensively developed as a port. It covers 10,532 acres of water and 4,419 acres of tidelands. Only 17 to 18% of the original Bay floor remains undisturbed by dredge or fill. Ninety percent of the original salt marshes and 50% of the original mudflats have been filled or dredged for development. Construction of dams and extensive use of groundwater in the Sweetwater and Otay Rivers has reduced the input from these rivers to the Bay by 76%. The majority of freshwater input to the Bay is from surface runoff from urban areas and intermittent flow from rivers and creeks during rain events. There are over 200 storm drain outfalls in San Diego Bay (Coastal Conservancy 2001). Pueblo San Diego Watershed (HU 908.00) The Pueblo San Diego watershed lies within the San Diego Bay WMA and is the smallest of the three San Diego Bay WMA watersheds, covering just over 36,000 acres. It is comprised of three hydrologic areas: Point Loma, San Diego Mesa, and National City. Major water bodies include Chollas Creek, Paleta Creek, and San Diego Bay. Pueblo San Diego is the most developed and most densely populated watershed in the San Diego Bay WMA. Containing the City of San Diego, population in the watershed is expected to reach over 591,000 by the year 2015. Land use in the watershed is primarily residential (54%), public facilities/utilities (13%), and parks and recreation (8%). The majority of land is privately owned with only a small percentage owned by government. Most of the watershed falls under the jurisdiction of the City of San Diego (84%). Other jurisdictions include La Mesa, Lemon Grove, National City, San Diego Unified Port District, and a small percentage of unincorporated land. Most of the beneficial uses for this watershed lie in its coastal waters; including those of the Bay (Table 11-1). Major impacts on water quality include surface water degradation, habitat degradation, sediment toxicity, and sewer overflows. Constituents of concern include trace metals and other toxic substances, and coliform bacteria (San Diego County 2002). Table 11-2 presents water bodies placed on the SWRCB 2002 303(d) list for this watershed. Rainfall for the Pueblo San Diego watershed is light with an average rainfall of 10.5 inches in coastal areas to 13.5 inches in the eastern portion of the watershed. The San Diego Formation is the principal aquifer in the watershed. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-2 Figure 11-1. San Diego Bay Watershed Management Area. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-3 Table 11-1. Beneficial uses within the Pueblo San Diego watershed. Beneficial Uses Inland Surface Waters Coastal Waters Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z Industrial Service Supply z Navigation z Contact Water Recreation O z Non-Contact Water Recreation z z Warm Freshwater Habitat z Estuarine Habitat z Wildlife Habitat z z Commercial and Sport Fishing z Rare, Threatened, or Endangered Species z Biological Habitats of Significance z Marine Habitat z Migration of Aquatic Organisms z Shellfish Harvesting z z = Existing O = Potential Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) There is one mass loading station in the Pueblo San Diego watershed. This mass loading station is within the Chollas sub-watershed (HAS 908.22). The Chollas Creek station (SD8) is located on the north fork of Chollas Creek near the intersection of 33rd and Durant Streets, just east of the Durant Street cul-de-sac in the City of San Diego. The Chollas sub-watershed is divided into two drainage areas. The north fork drains approximately 9,276 acres and the south fork drains approximately 6,997 acres. To avoid tidal influence, the monitoring station is installed on the north fork above the north and south fork confluence. The contributing runoff area consists of 9,105 acres, which is approximately 25% of the Pueblo San Diego watershed. This is considered to be representative of the entire Pueblo San Diego watershed because the land use distribution in the north fork portion of the Chollas sub-watershed is nearly identical to the land use distribution of the entire Pueblo San Diego watershed. Land use within the contributing runoff area is highly urban which includes 48% residential and 28% transportation. At the sampling site, Chollas Creek is a trapezoidal, concrete-lined channel that eventually discharges to San Diego Bay. Stream bioassessment monitoring in the Chollas Creek sub-watershed began in May of 2003. There is a limited amount of suitable stream habitat for monitoring, as most of the stream bed has been channelized. There is a reach downstream of the Federal Boulevard off-ramp from Highway 94 that has a natural stream bed with year-round flow. The in-stream habitat is good and is dominated by large, smooth cobble. The area lacks riparian trees, and upstream of the monitoring reach the stream is adjacent to light industrial development. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-4 Table 11-2. Water bodies on the SWRCB 303(d) list in the Pueblo San Diego watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor San Diego Bay Shoreline, Near Sub Base Point Loma 908.10 Benthic Community Effects, Sediment Toxicity San Diego Bay , Shelter Island Yacht Basin Point Loma 908.10 Dissolved Copper San Diego Bay Shoreline, Shelter Island Shoreline Park Point Loma 908.10 Bacteria Indicators San Diego Bay Shoreline, Downtown Anchorage Lindbergh 908.21 Benthic Community Effects, Sediment Toxicity San Diego Bay Shoreline, G St. Pier Lindbergh 908.21 Bacteria Indicators San Diego Bay Shoreline, Near Switzer Creek Lindbergh 908.21 Chlordane, Lindane, PAHs San Diego Bay Shoreline, Vicinity of B St. and Broadway Piers Lindbergh 908.21 Bacteria Indicators, Benthic Community Effects, Sediment Toxicity Chollas Creek Chollas 908.22 Bacteria Indicators, Cadmium, Copper, Diazinon, Lead, Zinc San Diego Bay Shoreline, Near Chollas Creek Chollas 908.22 Benthic Community Effects, Sediment Toxicity San Diego Bay Shoreline, 32nd St. Naval Station Chollas 908.22 Benthic Community Effects, Sediment Toxicity San Diego Bay Shoreline, Between Sampson and 28th Streets Chollas 908.22 Copper, Mercury, PAHs, PCBs, Zinc San Diego Bay Shoreline, Near Coronado Bridge Chollas 908.22 Benthic Community Effects, Sediment Toxicity San Diego Bay Shoreline, Seventh St. Channel El Toyan 908.31 Benthic Community Effects, Sediment Toxicity San Diego Bay Shoreline, North of 24th St. Marine Terminal Paradise 908.32 Benthic Community Effects, Sediment Toxicity Source: SWRCB 2003 Sweetwater Watershed (HU 909.00 The Sweetwater watershed is also part of the San Diego Bay WMA and is the largest of the three watersheds that border San Diego Bay, encompassing over 148,000 acres. The watershed includes three hydrologic areas: Lower Sweetwater, Middle Sweetwater, and Upper Sweetwater. Major water bodies within the Sweetwater watershed include the Sweetwater River, Sweetwater Reservoir, Loveland Reservoir, and San Diego Bay. Jurisdiction within the watershed is primarily the County of San Diego for the unincorporated lands (87%) with smaller portions split between the City of Chula Vista, La Mesa, Lemon Grove, National City, the City of San Diego, and the San Diego Unified Port District. Much of the undeveloped land in the Sweetwater watershed is occupied by the Cleveland National Forest, Cuyamaca Rancho State Park, and the unincorporated communities of Pine Valley, Descanso, Alpine, and the Viejas Indian Reservation. Land ownership is mostly private with the remaining areas controlled by local, state, federal governments, and tribal lands. Population for the watershed is approximately 300,000 and is expected to grow 22% by the year 2015. This is the lowest expected growth rate for any of the San Diego watersheds. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-5 The Sweetwater watershed provides many beneficial uses with its large areas of open space, state parks, national forests, rivers, reservoirs, and the shoreline of San Diego Bay (Table 11-3). Principal aquifers in the watershed include the Lower and Middle Sweetwater Basins and the San Diego Formation. Major impacts to the watershed include surface and groundwater quality degradation, habitat degradation, and invasive species. Constituents of concern include coliform bacteria, pesticides, and nutrients. Table 11-4 presents the water bodies that have been placed on the SWRCB 303(d) list. Rainfall in the watershed widely varies from 10.5 inches near the coast to approximately 35 inches in the far inland areas. Table 11-3. Beneficial uses within the Sweetwater watershed. Beneficial Uses Inland Surface Waters Coastal Waters (a) Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z z z Agricultural Supply z z z Industrial Service Supply z z z z Industrial Process Supply z z Navigation z Contact Water Recreation z z z Non-Contact Water Recreation z z z Commercial & Sport Fishing z Biological Habitats of Significance z z Warm Freshwater Habitat z z Cold Freshwater Habitat z z Wildlife Habitat z z z Rare, Threatened, or Endangered Species z z Marine Habitat z Migration of Aquatic Organisms z Estuarine Habitat z Shellfish Harvesting z (a) San Diego Bay Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) Table 11-4. Water bodies on the SWRCB 303(d) list in the Sweetwater watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor San Diego Bay Shoreline, at Chula Vista Marina La Nacion 909.12 Bacteria Indicators San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-6 The Sweetwater River (SR) mass loading station is located in Bonita, north of Bonita Road, under the Plaza Bonita Road Bridge. Sweetwater River is a natural channel at the sampling site. This station receives only localized runoff. The contributing runoff area consists of over 10,800 acres, which is 7% of the total watershed land area. The Sweetwater reservoir captures most of the runoff from the upper watershed and releases only during large storm events. Land use for the contributing runoff area is primarily a mix of residential (32%), parks (32%), and undeveloped (12%). Stream bioassessment in the Sweetwater River has occurred at three urban affected sites. The upstream site is located at the Highway 94 overcrossing in Rancho San Diego. The river has a fairly low gradient here, and the substrate is dominated by fine particulate sediment and lacks good quality riffles. The riparian zone is dense, providing a thick canopy over the stream bed. This site was not sampled in October of 2004 due to dry conditions. The lower monitoring site is in the Sweetwater County Park near Sweetwater Road. This reach of the river is low gradient, and the riparian zone is dense and undisturbed. The in-stream habitat is fair, dominated by small, unconsolidated gravel with poor substrate complexity. The riffles are infrequent with low flow velocity. Another site was sampled in October of 2002 in Long Canyon Creek along Acacia Avenue. This stream is runoff dominated and is channelized, and was sampled due to lack of flow in Sweetwater River. The Sweetwater River flows into San Diego Bay. The area of the River that is tidally influenced is known as the Sweetwater River Estuary, located on the border of National City and Chula Vista. The Estuary is a broad, straight, fairly deep channel that forms the mouth of the Sweetwater River, which is the Estuary’s primary source of fresh water. Tidal influence is somewhat restricted in the inner areas of the Estuary by bridge crossings at Interstate 5 and Broadway Street. The outer portion of the Estuary is surrounded by commercial and industrial influences to the north, but the Sweetwater Marsh National Wildlife Refuge borders the southern side of the outer Estuary. Freeways border both sides of the middle and inner Estuary north of Interstate 5. Of the three sites selected for the Ambient Bay and Lagoon Monitoring Program, one site was located in the inner stratum, one was located in the middle stratum, and one was located in the outer stratum. Otay Watershed (HU 910.00) The Otay watershed also lies within the San Diego Bay WMA and is approximately 98,500 acres. The watershed consists of three hydrologic areas: Coronado, Otay, and Dulzura. Major water bodies include the Upper and Lower Otay Reservoirs, Otay River, and San Diego Bay. Over 69% of the watershed is unincorporated with the remaining portions divided between the following jurisdictions: Port of San Diego, Chula Vista, Coronado, Imperial Beach, National City, and San Diego. Land ownership is predominantly private with a small percentage of local, state, and federally owned lands. The Otay watershed is one of the three least populated watersheds in the San Diego Region with approximately 143,000 people. That number is expected to increase 88% by the year 2015. Land use in the watershed is primarily vacant/undeveloped (52%), parks and recreation (27%), and residential (10%). San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-7 The Otay watershed provides many beneficial uses with conservation areas that include the San Diego National Wildlife Refuge, the Rancho Jamul Ecological Reserve, and approximately 23,000 acres that provide habitat for endangered plant and animal species as part of the Multiple Species Conservation Plan (Table 11-5). The two major reservoirs in the watershed supply water, important wildlife habitat, and recreational opportunities. The Lower Otay Reservoir lies at the end of the San Diego Aqueduct. The San Diego Formation is the principal aquifer in the watershed. Table 11-6 presents the water bodies that have been placed on the CWA 303(d) list. Annual rainfall varies from 8.25 inches at the coast to 19.5 inches in the inland areas. Most of the runoff from this watershed is collected upstream at the Otay Reservoir. The reservoir only releases water during extremely large rain events and thus no flow was recorded during the 2001-2002 monitoring season and subsequently, this station was decommissioned after that season. Table 11-5. Beneficial uses within the Otay watershed. Beneficial Uses Inland Surface Waters Coastal Waters (a) Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z z z Agricultural Supply z z z Industrial Service Supply z z z z Industrial Process Supply z z Commercial & Sport Fishing z Navigation z Hydropower Generation Contact Water Recreation z z z1 Non-Contact Water Recreation z z z Biological Habitats of Significance z Warm Freshwater Habitat z z Cold Freshwater Habitat z Estuarine Habitat z Wildlife Habitat z z z Rare, Threatened, or Endangered Species z z Marine Habitat z Migration of Aquatic Organisms z Spawning, Reproduction and/or Early Development Shellfish Harvesting z (a) San Diego Bay 1 Shore and boat fishing only. Other REC1 uses prohibited. Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) Table 11-6. Water bodies on the SWRCB 303(d) list in the Otay watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor San Diego Bay Shoreline, Tidelands Park Coronado 910.10 Bacteria Indicators San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-8 11.2 Storm Water Monitoring Summary Three storm events were monitored at the MLS on Chollas Creek and Sweetwater River during the 2004-2005 wet season events. These events took place on October 17, 2004 and February 11 and 18, 2005. The results from these storms are discussed in the following section (11.2.1) and presented in Table 11-7 (Chollas Creek) and Table 11-8 (Sweetwater River). A comparison of the results to previous years is provided in Section 11.2.2. 11.2.1 2004-2005 Results Chollas Creek Nine conventional constituents exceeded water quality objectives at Chollas Creek. Of the conventional constituents measured, TSS and turbidity concentrations exceeded WQO during all of the three storms monitored during the 2004-2005 wet weather season. In addition, COD exceeded the WQO during the October 17, 2004 storm event. Un-ionized ammonia exceeded the WQO during the February 18, 2005 storm event. None of the other nutrients monitored during the 2004-2005 wet weather season exceeded water quality objectives. All of the nutrients were detected at low levels during all three storms monitored. All three of the bacterial indicators had elevated density levels. Fecal coliform is the only indicator bacteria with a wet weather water quality objective and it exceeded the objective during all three storms monitored in 2004-2005. Chlorpyrifos and Diazinon were not detected during any of the storm events in 2004-2005, however, Malathion exceeded the WQO during the October 17, 2004 storm event. Most total and dissolved metals were detected at low levels. Total copper was detected at levels above water quality objectives during all three storm events. Total zinc was detected at levels above water quality objectives during October 17, 2004 and February 18, 2005. Dissolved zinc exceeded the WQO during the October 17, 2004 storm. The October 17, 2004 sample from Chollas Creek showed toxicity to Hyalella and Ceriodaphnia (See Section 3.1.6.2 for details on toxicity testing). The NOEC for Hyalella 96-hour survival was 50% of the test sample in comparison to 100% survival for the control. The NOEC for the Ceriodaphnia 7-day reproduction was 25% and was statistically different from the control which met the test criteria for reproduction. No toxicity was expressed in the other storm events monitored from Chollas Creek during 2004-2005. Table 11-7. Analytes measured at the Chollas Creek mass loading station.2/17/1994 3/24/1994 4/24/1994 11/10/1994 1/11/1995 2/14/1995 4/16/1995 11/1/1995 1/22/1996 1/31/1996 3/5/1996 12/9/1996 1/16/1997 11/10/199712/6/1997 3/14/1998 11/8/1998 1/25/1999 3/15/1999General / Physical / Electrical Conductivity umhos/cm447 176.3 110 193 693 179 427 334 487 310 155 1146 286 270 215Oil And Grease mg/L 15 USEPA Multi-Sector General Permit2.2 0.6 0.7 1.93 2.11 2.43 1.2 3.3 3.4 3.1 6 1.8 6.9 <0.5 4.56 1.29 1.56 0.95pH pH Units 6.5-8.5 Basin PlanBacteriologicalEnterococci MPN/100 mLFecal Coliform MPN/100 mL 4000 Basin Plan9,300 24,000 24,000 17,000 28,000 50,000 50,000 16,000 16,000 16,000 16,000 16,000 16,000 9,4501,600 1,600 1,600Total Coliform MPN/100 mL240,000 240,000 240,000 160,000 160,000 90,000 160,000 16,000 16,000 16,000 16,000 160,000 20,000 241,900 298,700 2,419,000Wet ChemistryAmmonia As N mg/L 0.4 0.9 1.4 0.3 0.7 0.6 0.64 0.31 <0.2 1.8 <0.2 <0.2 1.3 0.4 10 1 0.78 1.06Un-ionized Ammonia as Nμg/L 25 (a) Basin PlanBiological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit10 <338.930 25 13.3 18.1 14.5 6 <5 16 7.8 1549244019 6 11Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit47149 28488187 192 12290 8732131 731464413559 41 85Dissolved Organic Carbon mg/LDissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit0.2 0.2 0.4 0.3 0.4 0.4 0.3 0.5 0.6 0.7 0.2 0.3 0.4 <0.1 1.41 1.07 0.27 0.22Nitrate As N mg/L 10 Basin Plan2.7 1.4 2.7 0.7 1.2 0.98 1.8 1.2 0.91 0.82 0.8 0.81 3.5 0.52 0.4 1.1 0.98 0.44Nitrite As N mg/L 1 Basin Plan<0.05 <0.05 <0.05 <0.05 <0.05 <0.050.08 <0.05 0.06 0.12 0.14Surfactants (MBAS) mg/L 0.5 Basin Plan0.12 0.470.690.41 0.07 0.07 0.3 0.16 <0.1 1 <0.1 <0.1 <0.1 0.070.660.48 0.19 0.07Total Dissolved Solids mg/L 500 Basin Plan by watershed250 150 270 460 180 250 250 250 264 148 204 194 278 374 250 344 249 125 222Total Kjeldahl Nitrogen mg/L4.3 4.4 3.9 1.6 <1 7.1 3.4 1.9 1.8 2.7 1.1 1.8 1.6 <1 15 0.44 1.25 3.61Total Organic Carbon mg/LTotal Phosphorus mg/L 2 USEPA Multi-Sector General Permit0.4 0.7 0.9 0.5 0.6 0.6 0.9 0.7 0.3 0.3 1.1 0.3 0.5 0.7 <0.12.21.28 0.3 0.17Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit220 700 400 650 330 1200 470751849213092488 182 315 8057.58280 159Turbidity NTU 20 Basin Plan86 54 54 40 64 85 66 54.2 68.35.7 18.437 290 90 29 24 69 38 21PesticidesChlorpyrifosμg/L 0.02 CA Dept. of Fish & Game0.1<0.5*Diazinonμg/L0.08CA Dept. of Fish & Game0.46 0.46 0.53Malathionμg/L 0.43 CA Dept. of Fish & GameHardnessTotal Hardness mg CaCO3/L 120 71 110 150 58 100 120 91 74.5 52.2 78.6 57.4 61.5 116 39 96.4 77 42.5 90.8Total MetalsAntimonymg/L0.006Basin Plan<0.001 0.0013 <0.001 0.0023 <0.001 <0.001 0.001 <0.003 <0.003 0.0016 <32* <32* <0.0015 <0.0015 <0.0015Arsenic mg/L0.34/0.0540 CFR 131/ Basin Plan<0.005 <0.005 <0.005 <0.005 0.011 0.008 0.006 0.006 0.004 0.005 0.002 <0.053* <0.053* 0.006 0.0018 0.003Cadmium mg/L(b)40 CFR 1310.002 0.002 0.001 0.001 0.001 0.002 0.003 0.001 0.0006 0.0007 0.0003 <0.004 <0.004 0.002 <0.00025 <0.00025Chromium mg/L(b)CTR (Cr VI)0.005 0.006 0.008 0.004 0.003 0.01 0.007 <0.005 <0.010 0.010 <0.005 <0.007 0.011 <0.005 0.0150.035Copper mg/L(b)40 CFR 1310.034 0.029 0.044 0.036 0.017 0.04 0.085 0.046 0.020.01 0.0170.028 0.0280.006 <0.0050.015Lead mg/L(b)40 CFR 1310.11 0.140.07 0.0350.044 0.11 0.140.023 0.0160.0580.003 <0.0420.095<0.001 0.0070.082Nickel mg/L(b)/0.140 CFR 131/ Basin Plan0.011 0.008 0.014 0.016 0.006 0.011 0.013 0.011 <0.010 <0.010 0.009 <0.015 <0.015 0.04 0.028 0.016Selenium mg/L0.0240 CFR 131<0.0005 <0.0005 <0.0005 <0.0005 0.001 0.001 0.002 <0.004 <0.003 0.001 <0.075 <0.075 0.002 <0.001 <0.001Zinc mg/L(b)40 CFR 1310.26 0.24 0.32 0.18 0.15 0.36 0.56<0.025 0.070.20 0.176 0.110.092 0.03 0.0480.21Dissolved MetalsAntimonymg/L (e) 40 CFR 1310.0022 <0.001 <0.001 <0.001 <0.0015 <0.0015 <0.0015 <0.003 <0.003Arsenic mg/L 0.34 (c) 40 CFR 131<0.005 <0.005 <0.005 <0.005 0.004 0.003 0.002 0.005 <0.003Cadmium mg/L (b) 40 CFR 1310.0002 <0.0002 <0.0002 <0.0002 <0.00025 <0.00025 0.00044 0.0005 0.0012Chromium mg/L (b) 40 CFR 1310.002 0.0012 <0.001 0.001 <0.005 <0.005 <0.005 <0.010 <0.010Copper mg/L (b) 40 CFR 1310.013 <0.005 0.005 0.010 0.012 0.008 0.034 0.010 0.020Lead mg/L (b) 40 CFR 1310.003 <0.001 <0.001 <0.001 0.002 0.002 0.018 0.015 0.007Nickel mg/L (b) 40 CFR 1310.013 <0.005 <0.005 <0.005 <0.005 <0.005 0.009 <0.010 0.020Selenium mg/L 0.02 (d) 40 CFR 131<0.0005 0.001 <0.0005 <0.0005 <0.001 <0.001 <0.001 <0.002 <0.003Zinc mg/L (b) 40 CFR 1310.07 0.014 0.012 0.069 <0.025 0.032 0.141 0.080 0.040ToxicityCeriodaphnia 96-hr LC50 (%) 100Ceriodaphnia 7-day survival NOEC (%) 100reproduction NOEC (%) 100Hyalella 96-hrNOEC (%) 100Selenastrum 96-hr NOEC (%) 1001997-981995-96 1996-97ANALYTE UNITS WQO SOURCE1998-99See last page for footnotes and source references.1993-94 1994-95 Table 11-7. Analytes measured at the Chollas Creek mass loading station.General / Physical / Electrical Conductivity umhos/cmOil And Grease mg/L 15 USEPA Multi-Sector General PermitpH pH Units 6.5-8.5 Basin PlanBacteriologicalEnterococci MPN/100 mLFecal Coliform MPN/100 mL 4000 Basin PlanTotal Coliform MPN/100 mLWet ChemistryAmmonia As N mg/L Un-ionized Ammonia as Nμg/L 25 (a) Basin PlanBiological Oxygen Demand mg/L 30 USEPA Multi-Sector General PermitChemical Oxygen Demand mg/L 120 USEPA Multi-Sector General PermitDissolved Organic Carbon mg/LDissolved Phosphorus mg/L 2 USEPA Multi-Sector General PermitNitrate As N mg/L 10 Basin PlanNitrite As N mg/L 1 Basin PlanSurfactants (MBAS) mg/L 0.5 Basin PlanTotal Dissolved Solids mg/L 500 Basin Plan by watershedTotal Kjeldahl Nitrogen mg/LTotal Organic Carbon mg/LTotal Phosphorus mg/L 2 USEPA Multi-Sector General PermitTotal Suspended Solids mg/L 100 USEPA Multi-Sector General PermitTurbidity NTU 20 Basin PlanPesticidesChlorpyrifosμg/L 0.02 CA Dept. of Fish & GameDiazinonμg/L0.08CA Dept. of Fish & GameMalathionμg/L 0.43 CA Dept. of Fish & GameHardnessTotal Hardness mg CaCO3/LTotal MetalsAntimonymg/L0.006Basin PlanArsenic mg/L0.34/0.0540 CFR 131/ Basin PlanCadmium mg/L(b)40 CFR 131Chromium mg/L(b)CTR (Cr VI)Copper mg/L(b)40 CFR 131Lead mg/L(b)40 CFR 131Nickel mg/L(b)/0.140 CFR 131/ Basin PlanSelenium mg/L0.0240 CFR 131Zinc mg/L(b)40 CFR 131Dissolved MetalsAntimonymg/L (e) 40 CFR 131Arsenic mg/L 0.34 (c) 40 CFR 131Cadmium mg/L (b) 40 CFR 131Chromium mg/L (b) 40 CFR 131Copper mg/L (b) 40 CFR 131Lead mg/L (b) 40 CFR 131Nickel mg/L (b) 40 CFR 131Selenium mg/L 0.02 (d) 40 CFR 131Zinc mg/L (b) 40 CFR 131ToxicityCeriodaphnia 96-hr LC50 (%) 100Ceriodaphnia 7-day survival NOEC (%) 100reproduction NOEC (%) 100Hyalella 96-hrNOEC (%) 100Selenastrum 96-hr NOEC (%) 100ANALYTE UNITS WQO SOURCESee last page for footnotes and source references.2/12/2000 3/5/2000 4/17/2000 10/27/2000 1/8/2001 2/13/2001 11/29/2001 2/17/2002 3/8/2002 11/8/2002 2/11/2003 2/25/2003 2/3/2004 2/18/2004 3/2/2004 10/17/04 02/11/05 02/18/05186 187 185 258 319 279 155 310 242 315 211 91.2 152.5 148 231 565 348 1591.92 2.04 1.48 12 4 1 5 10 8 4.24 3.54 2.47 1.61 2.17 3.43 4.17 1.12 <1 0% 0.207.4 7.4 8 6.96 7.58 7.41 4.05 6.57 6.96 7.09 7.61 7.81 0% 0.00130,000 26,000 80,000 170,000 110,000 220,000 30,000 50,000 80,000 50,000 220,000 17,000 170,000 30,000 80,000<2 1,600 1,60070,000 27,000 14,000 30,000 23,000 70,000 50,000 30,000 13,000 22,000 30,000 17,000140,000 11,000 70,00078% 6.30500 1,600 1,600 1,100,000 500,000 30,000 80,000 300,000 300,000 2,400,000 230,000 300,000 110,000 80,000 800,000 3,000,000 130,000 170,0001.65 <0.1 0.21 1.2 1.5 0.6 0.7 2.14 1.04 0.54 0.79 0.52 0.52 0.58 3.1 2.13 0.28 0.191.52 8.93 3.12 0.00 0.59 6.53 2.4 5.946.73% 0.087.8 2.54 6.1 1532.2<2 2773.329 8.0131.821.041.42.2534.6138 4.83 3.79 24% 0.7541 104 57150109 100 71244 48811918443222 2716950189 <25 41% 1.1411.3 19.2 10.8 5.8 11.6 6.07 134 2.22 2.860.33 0.26 0.22 0.08 0.94 0.39 0.9 0.75 0.46 0.41 0.40 0.14 0.51 0.32 0.21 1.68 0.2 <0.05 0% 0.223.22 1.04 3.1 0.8 2.1 0.8 1.2 1.6 1.3 0.71 1.04 0.45 0.83 0.79 0.37 4.38 0.62 0.61 0% 0.130.086 <0.05 <0.05 0.21 0.22 0.05 0.11 0.22 0.18 0.09 0.12 0.07 0.06 0.08 <0.05 0.15 0.05 0.05 0% 0.060.35 0.22 0.130.7<0.5 <0.5 <0.50.7<0.5 0.3 0.2 <0.1 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 14% 0.55120 111 140 191 236 173 71 254 199 195 121 87 134 222 129 665 122 1122.98 3.1 2.36 2.37 5.9 0.97 4.6 5.7 9.1 2.5 2.4 1.6 3 3.6 3.8 18.6 5.4 3.422.8 27.0 5.45 21.9 20.9 15.9 190 7.58 10.70.46 0.33 0.6 0.12 0.96 0.49 1.08 1.552.080.68 0.67 0.76 0.91 0.63 0.45 1.85 0.3 0.45 5% 0.364576220067294 13967151 49363193 2952429056753 135 27573% 2.9250 27 38 72.2 200 96 63.3 36.5 121 57.1 121 178 259 102 37.5300 40.1 82.295% 4.15<0.5* <0.5* <0.5* <0.5* <0.5* <0.5*0.04 0.13 0.04 0.111<0.03*0.038<0.01 <0.01 <0.01 <0.01 <0.01 <0.01 35% 3.05<0.5* <0.5* <0.5*0.75<0.5* <0.5*0.68 0.82 0.61 0.424 0.26 0.09 0.081 0.158 0.088<0.01 <0.01 <0.01 49% 2.250.25 0.28 <0.10 0.164 0.162 0.1680.6010.091 0.065 11% 0.4740.9 35.1 45.5 85 78 59 68 111 148 69.1 78 44 87 88 74 244 40 46<0.0015 <0.0015 <0.0015 0.003 0.003 0.002 <0.002 0.003 0.005 <0.002 0.005 0.004 <0.005 <0.006 <0.0050.005 <0.005 <0.0050% 0.32<0.001 0.007 0.005 0.004 0.006 0.004 0.002 0.004 0.006 0.003 0.004 0.003 0.009 0.006 0.0030.007 0.004 <0.0020% 0.11<0.000250.002<0.00025 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 0.001 0.002 0.0010.003 <0.001 <0.0016% 0.30<0.005 <0.005 <0.005 0.007 0.013 0.007 0.012 0.009 0.019 <0.005 0.010 <0.005 0.025 0.019 <0.005<0.005 <0.005 <0.0050% 0.010.029 0.016 0.014 0.027 0.049 0.016 0.027 0.053 0.0560.028 0.033 0.0160.07 0.068 0.0360.122 0.009 0.01594% 2.790.015 <0.001 <0.005 0.022 0.055 0.027 0.028 0.032 0.061 0.017 0.029 0.0230.079 0.096 0.0570.079 0.008 0.018<0.005 <0.005 <0.005 0.012 0.014 0.005 0.009 0.015 0.017 0.007 0.008 0.004 0.016 0.014 0.0020.040 0.003 0.0030% 0.03<0.001 <0.001 <0.001 <0.002 0.003 <0.002 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004 <0.005 <0.005 <0.005<0.005 <0.005 <0.0056% 0.180.0960.0500.08 0.150 0.290 0.12 0.162 0.314 0.4300.118 0.230 0.1540.496 0.561 0.3941.180.0540.10082% 2.13<0.0015 <0.0015 <0.0015 0.004 <0.002 <0.002 <0.002 <0.002 <0.002 0.002 0.002 0.002 <0.005 <0.006 <0.005<0.005 <0.005 <0.005<0.001 0.005 <0.001 0.003 0.002 0.003 <0.001 <0.001 0.003 0.003 0.002 0.002 0.002 0.002 <0.002<0.002 <0.002 <0.0020% 0.01<0.00025 <0.00025 <0.00025 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.0010% 0.13<0.005 <0.005 <0.005 0.005 <0.005 <0.005 0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.0050% 0.01<0.005 <0.005 <0.0050.017 0.013<0.0050.009a 0.024a 0.018b0.022 0.052 0.0080.005 0.009 0.0050.024 0.006 <0.00541% 1.09<0.001 <0.001 <0.005 0.003 0.002 0.014 <0.002 <0.002 0.002 0.006 <0.002 <0.002 <0.002 <0.002 <0.0020.004 <0.002 <0.0020% 0.08<0.005 <0.005 <0.005 0.011 0.007 0.002 0.004 0.010 0.008 0.006 0.004 <0.002 <0.002 0.002 <0.0020.027 <0.002 <0.0020% 0.01<0.001 <0.001 <0.001 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004 <0.005 <0.005 <0.005<0.005 <0.005 <0.0050% 0.060.019 0.028 0.008 0.0900.1100.030 0.053 0.118 0.0790.152 0.1390.018 <0.02 0.034 <0.020.2670.023 <0.0222% 0.6050 2510075 50 7577.78>100 >100 >100 >100 >100 >100 >100 >100 40% 0.8050 2510025 25 2525 50100 100 100 100 100 100 100 47% 1.6025 12.5 2550100 100 100 100 10025100 100 42% 1.8350 6.25 12.510050 5050100 10050 5010050100 100 60% 2.53100 100 100 100 100 100 100 100 100 100 100 100 0% 0.001999-002004-052002-032000-01 2001-02Frequency Above WQOMean Ratio to WQO2003-04 Table 11-7. Analytes measured at the Chollas Creek mass loading station.SourcesBlank spaces have been verified and no data is available due to changes in the monitoring program.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Table 3 - Parameter benchmark values.(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(e) USEPA has not published an aquatic life criterion value.Shaded text – exceeds water quality objective.* Indicates detection limit exceeds water quality objective.(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.USEPA Federal Register Document 40 CFR Part 131, May 18, 2000.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958. Table 11-8. Analytes measured at the Sweetwater mass loading station.2/17/02 3/17/02 4/25/02 12/16/02 2/11/03 2/25/03 11/12/03 2/3/04 2/18/04 10/17/04 2/11/05 2/18/05Electrical Conductivity umhos/cm 3820 3430 2980 2990 2760 1955 3040 1742 1995 529 5070 3260Oil And Grease mg/L 15 USEPA Multi-Sector General Permit 1 1 1 4.47 2 1 4.43 <1 1.05 <1 <1 <1 0% 0.10pH pH Units 6.5-8.5 Basin Plan 7.5 7.4 7.3 7.56 6.87 6.94 7.20 7.83 7.58 7.24 7.52 7.49 0% 0.00Enterococci MPN/100 mL 300 16,000 9,000 8,000 14,000 30,000 18,792 1,879 17,000 800 3,000 50,000Fecal Coliform MPN/100 mL 400 Basin Plan 130500 11,000 23,000 7,000 1,700 4,000 2,200 2,3003001,300 1,30083% 11.40Total Coliform MPN/100 mL 23,000 5,000 230,000 30,000 30,000 170,000 300,000 130,000 130,000 30,000 13,000 28,000Ammonia As N mg/L 0.16 0.3 0.2 0.25 0.28 0.19 0.16 0.1 0.15 0.39 0.14 0.14Un-ionized Ammonia as Nμg/L25 (a) Basin Plan2.28 0.64 0.420.67 1.44 1.55 1.0 0.8 1.1 0% 0.04Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit 2 14.2 4.7 <2.0 20.4 5.89 9.3246.715.3 19.8 2.57 3.42 8% 0.40Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit 70 63 55 59 85 39 104 69 86 4412374 8% 0.60Dissolved Organic Carbon mg/L 9.68 25.2 8.94 21.9 7.94 88.2 25.7 5.24 6.19Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit <0.05 0.2 0.1 0.34 0.20 0.10 0.4 0.18 0.12 0.2 0.18 0.45 0% 0.10Nitrate As N mg/L 10 Basin Plan 0.4 0.3 0.2 0.54 0.81 0.39 2.19 0.25 0.27 0.07 1.02 1.93 0% 0.07Nitrite As N mg/L 1 Basin Plan <0.05 <0.05 <0.05 0.06 <0.05 <0.05 0.08 <0.05 <0.05 <0.05 <0.05 <0.05 0% 0.03Surfactants (MBAS) mg/L 0.5 Basin Plan <0.5 <0.5 <0.5 <0.1 <0.1 <0.1 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0% 0.40Total Dissolved Solids mg/L 1500 Basin Plan by watershed200010502870793166011501880 1780 22302860 23701410 67% 1.23Total Kjeldahl Nitrogen mg/L 1.5 3 1.2 1.0 1.0 0.8 2.8 <0.5 0.7 2.1 1.4 1.8Total Organic Carbon mg/L 40.7 12.9 6.72 20.8 12.5 96.4 30.1 10.9 11.7Total Phosphorus mg/L 2 USEPA Multi-Sector General Permit 0.18 0.29 0.1 0.54 0.22 0.14 0.43 0.22 0.16 0.25 0.57 0.47 0% 0.15Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit 21 47 23 74 14 51 <20 <20 <20 20 261028% 0.34Turbidity NTU 20 Basin Plan 7.720.28.2462.91346.515.2 11.5 16.8 4.03 5.8 48.8 33% 1.09Chlorpyrifosμg/L 0.02 CA Dept. of Fish & Game <0.03* <0.03*0.03 0.053 0.059<0.03* <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 25% 0.90Diazinonμg/L 0.08 CA Dept. of Fish & Game0.10 0.27<0.030.301 0.146 0.171 0.084<0.01 0.026 <0.01 <0.01 <0.01 50% 1.18Malathionμg/L 0.43 CA Dept. of Fish & Game 0.24 <0.10 <0.10 0.423 <0.01 <0.01 <0.01 <0.01 <0.01 0% 0.20Total Hardness mg CaCO3/L 932 499 1010 344 758 549 817 728 816 1210 991 556Antimony mg/L 0.006 Basin Plan <0.002 <0.002 <0.002 0.004 0.004 0.003 <0.005 <0.005 <0.006<0.005 <0.005 <0.0050% 0.41Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan 0.002 0.002 0.003 0.004 0.002 0.003 0.005 0.007 0.0050.004 0.005 <0.0020% 0.07Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.0010% 0.01Chromium mg/L (b) CTR (Cr VI) <0.005 0.007 <0.005 0.009 0.005 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.0050% 0.00Copper mg/L (b) 40 CFR 131 <0.005 0.010 0.006 0.010 0.018 0.007 0.009 0.013 0.012<0.005 <0.005 0.0050% 0.10Lead mg/L (b) 40 CFR 131 0.002 0.006 0.003 0.010 0.003 <0.002 0.002 <0.002 0.003<0.002 <0.002 0.002Nickel mg/L (b)/0.1 40 CFR 131/ Basin Plan 0.003 0.003 0.004 <0.002 0.002 <0.002 0.004 0.002 <0.0020.002 0.003 0.0020% 0.00Selenium mg/L 0.02 40 CFR 131 0.003 <0.002 <0.002 <0.004 <0.004 <0.004 <0.005 <0.005 <0.005<0.005 <0.005 <0.0050% 0.11Zinc mg/L (b) 40 CFR 131 <0.02 0.045 <0.020 0.042 0.029 0.025 0.036 <0.02 0.029<0.02 <0.02 <0.020% 0.04Antimony mg/L (e) 40 CFR 131 <0.002 <0.002 <0.002 0.006 <0.002 0.004 <0.005 <0.005 <0.006<0.005 <0.005 <0.005Arsenic mg/L 0.34 (c) 40 CFR 131 <0.001 0.001 0.003 0.003 0.003 0.003 0.003 0.004 0.003<0.002 <0.002 <0.0020% 0.00Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.0010% 0.01Chromium mg/L (b) 40 CFR 131 <0.005 <0.005 <0.005 0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.0050% 0.00Copper mg/L (b) 40 CFR 131 <0.005 <0.005 <0.005 0.007 0.025 0.008 0.005 0.006 0.008<0.005 <0.005 <0.0050% 0.08Lead mg/L (b) 40 CFR 131 <0.002 <0.002 <0.002 0.002 <0.002 <0.002 <0.002 <0.002 <0.002<0.002 <0.002 <0.002Nickel mg/L (b) 40 CFR 131 0.004 <0.002 0.003 <0.002 0.002 <0.002 0.003 0.002 <0.0020.002 0.003 0.0020% 0.00Selenium mg/L 0.02 (d) 40 CFR 131 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004 <0.005 <0.005 <0.005<0.005 <0.005 <0.0050% 0.10Zinc mg/L (b) 40 CFR 131 <0.020 <0.020 <0.020 0.043 0.097 0.021 <0.02 <0.02 <0.02<0.02 <0.02 <0.020% 0.042001-02 2002-03Dissolved Metals2003-04Total MetalsANALYTE UNITS WQO SOURCEBacteriologicalFrequency Above WQOMean Ratio to WQO2004-05HardnessWet ChemistryPesticidesGeneral / Physical / Organic Table 11-8. Analytes measured at the Sweetwater mass loading station.2/17/02 3/17/02 4/25/02 12/16/02 2/11/03 2/25/03 11/12/03 2/3/04 2/18/04 10/17/04 2/11/05 2/18/052001-02 2002-03 2003-04ANALYTE UNITS WQO SOURCEFrequency Above WQOMean Ratio to WQO2004-05Ceriodaphnia 96-hr LC50 (%) 100 >10070.71>10072.22>100 >100 >100 >100 >10050>100 >100 25% 0.40Ceriodaphnia 7-day survival NOEC (%) 100 1002510050100 100 100 100 10025100 100 25% 0.83Ceriodaphnia 7-day reproduction NOEC (%) 100 10050 50 50100 100 100 100 10012.5 50100 42% 1.33Hyalella 96-hr NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00Selenastrum 96-hr NOEC (%) 10050 50 25 12.5100 100 100 1005050100 100 50% 1.67SourcesUSEPA Federal Register Document 40 CFR Part 131, May 18, 2000.USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-SectorGeneral Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance,October 30, 2000. Table 3 - Parameter benchmark values.Siepmann and Finlayson 2000.Basin Plan, September 8, 1994.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.* Indicates detection limit exceeds water quality objective.(e) USEPA has not published an aquatic life criterion value.(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.Blank spaces have been verified and no data is available due to changes in the monitoring program.ToxicityShaded text – exceeds water quality objective.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-14 Sweetwater River Most conventional constituents monitored for in the Sweetwater River were detected at low levels with only a few exceedances during the 2004-2005 monitoring season. TDS was the only constituent with a persistent problem. TDS exceeded the WQO during October 17, 2004 and February 11, 2005 storms. COD exceeded the WQO during the February 11, 2005 storm event, and TSS exceeded the WQO on February 18, 2005. Fecal coliform exceeded the REC-1 water quality objective during two of the storms. Total coliform and enterococcus also had elevated density levels, however there are no water quality objectives for total coliform and enterococcus to compare these results. None of the objectives for nutrients, pesticides, total metals, and dissolved metals were exceeded in the 2004-2005 season at the Sweetwater River mass loading station. The October 17, 2004 sample from Sweetwater River showed toxicity to Ceriodaphnia and Selenastrum (See Section 3.1.6.2 for details on toxicity testing). For Ceriodaphnia, the NOEC for the 7-day survival test was 25% in comparison to 90% for the control. The NOEC for the 7-day reproduction test was 12.5% and was statistically different from the control which met the test criteria for reproduction. For Selenastrum, the NOEC for 96-hour algal cell growth was 50% of the test sample and was statistically different from the control which met the test criteria for algal cell growth. Toxicity to Ceriodaphnia was also observed during the February 11, 2005 storm event. No toxicity to Hyalella was observed in any of the Sweetwater River samples collected in 2004-2005. 11.2.2 Relationships/Analyses Chollas Creek Chollas Creek is one of two water bodies in San Diego County which has been monitored since 1994. The larger number of sample points allow for trend analyses to be conducted. Trend analysis graphs using these historical data are presented in Appendix C. Five conventional constituents have had water quality objective exceedances throughout the 12 year monitoring history at Chollas Creek. These include BOD, COD, MBAS, TSS, and turbidity. During this time period, turbidity has exceeded the WQO 95% (35/37) of the time, TSS exceeded the WQO 73% (27/37) of the time, COD exceeded the WQO 42% (15/36) of the time, and BOD exceeded the WQO 22% (8/37) of the time. Surfactants (MBAS) exceeded the water quality objective only 11% (4/36) of the time and actually had more non-detect values (15/36) than exceedances. Turbidity was the only conventional constituent to have a significant increasing trend, although the trend is weak (R2=0.12). Nutrients were also monitored at Chollas Creek since 1994, with the exception of un-ionized ammonia as N which was initiated in the Fall of 2002. Only two nutrient constituents had detectable levels above a water quality objective. Un-ionized ammonia was detected once (11%) above the WQO during nine monitoring events. Total phosphorus was detected above the WQO of 2.0 mg/L twice (5%) during 37 monitoring events. The remaining nutrient results were either non-detect or below respective water quality objectives. Total and fecal coliform values have consistently been elevated during the 12 year monitoring period. Fecal coliform, the only bacterial indicator with a water quality objective, has exceeded the criteria of San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-15 4,000 MPN/100mL 29 times out of 35 storm events (83%). During the 1998-1999 and 1999-2000 monitoring year, however, fecal coliform levels were an order of magnitude lower than all other observations, and there was even a single non-detect value. Monitoring for enterococcus began during the 2000-2001 wet weather season. Enterococcus values have been persistently high. None of the bacterial indicators analyzed for had a statistically significant (p<0.05) trend. Monitoring for Chlorpyrifos and Diazinon started in the Fall of 1998. Analytical methods used in 2000-01 and 2001-02 did not achieve detection limits below the current water quality objectives for Chlorpyrifos (0.5 μg/L vs 0.02 μg/L) or Diazinon (0.5 μg/L vs 0.08 μg/L) and are not used in the scatterplots or trend analysis. With the exception of Chlorpyrifos results for 2003-2004 and 2004-2005, all historical results for Chlorpyrifos and Diazinon were either above the water quality objective or had a non-detect result greater than the water quality objective. Chlorpyrifos has not been detected in Chollas Creek or Sweetwater River during the past two years. Diazinon was not detected during any monitoring events in 2004-2005 at both MLS, however concentrations exceed WQO during all three events in Chollas Creek and during one event in 2003-2004. All three samples of Diazinon exceeded the WQO during the 2003- 04 monitoring season at the Chollas MLS, however there were no exceedances during the 2004-05 monitoring season. There was one WQO exceedance for Diazinon at the Sweetwater MLS during the 2003-04 monitoring season but no exceedances during the 2004-05 monitoring season. Analysis for Malathion began in Fall of 2002. Low levels of Malathion have been detected and only one storm has exceeded the WQO. None of the pesticides analyzed had a statistically significant (p<0.05) trend. Total metals have been analyzed during every storm event since 1994 except for three storm events in Spring 1996. Total copper and zinc have exceeded water quality objectives the most, with copper exceeding 85% (29/34) and zinc exceeding 79% (27/34) of the time. Historical results show total lead as frequently exceeding the water quality objectives (8 of the first 13 monitored storm events); however, it has only exceeded the water quality objective three times since 2000 (all three times occurred during the 2003-2004 wet weather season). Despite the total lead exceedances in the previous monitoring season, there is a significant but weak decreasing trend in total lead concentrations (R2=0.14). Dissolved metals were not monitored in Spring 1994 or during the period from Spring 1996 through Spring 1997. With the exception of dissolved copper and zinc, dissolved metals have either not been detected or detected at levels below the water quality objectives. Dissolved copper has exceeded the water quality objectives eight times during the 27 storm events monitored (30%). Dissolved zinc has only had concentrations greater than its WQO four times during the 27 storm events monitored (15%). Results of the chi-square test for Chollas Creek showed significant relationships for all Ceriodaphnia endpoints with Chlorpyrifos. Acute survival and reproduction were significant at p=0.004 with only one storm when Chlorpyrifos was above the WQO and no toxicity was observed (only the last four years were included in the analysis due to the high detection limits in the 2000-01 storm season). Chronic survival had a significant relationship with Chlorpyrifos at p=0.023. Toxicity to Ceriodaphnia has decreased in the last two years of sampling while intermittent toxicity to Hyalella has continued to be observed. In order to illustrate the magnitude of the water quality exceedances for 2004-2005, the ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern. The results are shown in Figure 11-2. The largest single exceedance was for fecal coliform, which exceeded the WQO by 35 times during the October 17, 2004 storm. There were also noticeable single exceedances for turbidity (15 times the WQO), TSS (7.5 times the WQO), total zinc (4.5 times the WQO), BOD (4.5 times the WQO), COD (4.2 times the WQO), total copper (3.8 times the WQO), and San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-16 Ceriodaphnia 7-day reproduction tests (3 times the WQO) all during the October 17, 2004 storm event. The average magnitude of water quality exceedances was also determined for each constituent by calculating the mean ratio of water quality results to the WQOs from all storm events from October 2001 through April 2004. Mean ratios are illustrated in Figure 11-2. The largest average exceedance for the period of record was for fecal coliform, which exceeded the WQO by nearly 8 times. There were also notable average exceedances ratios for turbidity (5.4 times), Diazinon (4.5 times), total copper (3.5 times), and total zinc (3 times). TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 20 40 Ratio to WQOMean Ratio (Oct 01 to Apr 04) 10/17/04 2/11/05 2/18/05 Above WQO Figure 11-2. Chollas Creek water quality ratios. In addition to the wet weather monitoring discussed above, there were a total of 23 dry weather monitoring sites in the Pueblo San Diego watershed. Of these 4 sites are located in the Chollas sub- watershed. Further, only four of these sites are located upstream of the MLS on Chollas Creek (See Section 3.4 for details on dry weather sampling). San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-17 Table 11-9 lists exceedances of dry weather action levels and the ratios of exceedance for COC that were measured during 2004 dry weather monitoring program for dry weather stations upstream of the MLS. There were dry weather exceedances for turbidity, ammonia, phosphorus, MBAS, dissolved copper, Diazinon, total and fecal coliform, and enterococcus. Of these, turbidity, total coliform, and enterococcus had average ratios of exceedance greater than 1.0. A map showing dry weather exceedances for all sites in the WMA is presented in Figure 11-3. Turbidity, fecal coliform, ammonia and copper (total during wet weather and dissolved during dry weather) were the only constituents that exceeded both in the 2004-2005 wet weather monitoring and the 2004 dry weather monitoring efforts. Sweetwater River Results for conventional constituents in 2004-2005 were similar to apparent trends for previous years. Only TDS has frequently exceeded water quality objectives having results greater than 1500 mg/L during 8 of the last 12 storm events (66%). Nutrients have been consistently at low or non-detectable levels during the past four wet weather seasons in Sweetwater River. Fecal coliform has consistently exceeded water quality objectives, with values above the 400 MPN/100mL REC-1 standard 10 times during the last 12 storm events. In 2004-2005, Diazinon did not exceed the WQO during any storm events. However, Diazinon did exceed water quality objectives during six out of the nine storm events prior to the 2004-2005 wet weather season and a significant decreasing trend was observed (R2=0.34). Total and dissolved metals have not exceeded water quality objectives at Sweetwater River during any of the monitoring events. Concentrations of the analyzed metals appear to be fairly consistent and low, with total and dissolved copper concentrations varying the greatest (total copper range = <0.005 to 0.018 mg/L and dissolved copper range = <0.005 to 0.025 mg/L). In order to illustrate the magnitude of the water quality exceedances for 2004-2005, the ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern. The results are shown in Figure 11-4. The largest single exceedance was for the Ceriodaphnia seven day reproduction toxicity test, which exceeded the WQO by seven times during the October 27, 2004 storm. There were also notable single exceedances for fecal coliform (3.3 times the WQO) and the Ceriodaphnia seven day survival test (3.1 times the WQO). The average magnitude of water quality exceedances was also determined for each constituent by calculating the mean ratio of water quality results to the WQOs from all storm events from October 2001 through April 2004. Mean ratios are illustrated in Figure 11-4. The largest average exceedance for the period of record was for turbidity (41 times the WQO). There was also a notable average exceedance ratio for fecal coliform (13 times the WQO). Table 11-9. Pueblo San Diego 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* Turbidity 3 4 2.29 Ammonia 1 4 0.52 Phosphorus 2 4 0.75 MBAS 1 4 0.76 Dissolved Copper 1 4 0.33 Diazinon 1 4 0.78 Total Coliform 2 4 3.64 Fecal Coliform 1 4 0.29 Enterococcus 2 4 3.78 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-18 Figure 11-3. San Diego Bay WMA dry weather exceedance map. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-19 TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 20 40 Ratio to WQOMean Ratio (Oct 01 to Apr 04) 10/27/04 2/11/05 2/18/05 Above WQO Figure 11-4. Sweetwater River water quality ratios. In addition to the wet weather monitoring discussion above, there were a total of 34 dry weather monitoring sites in the Sweetwater River watershed. Five of these sites were located upstream of the MLS on Sweetwater River (See Section 3.4 for details on dry weather sampling). Table 11-10 lists exceedances of dry weather action levels and the ratios of exceedance for COC that were measured during the 2004 dry weather monitoring program for dry weather stations upstream of the MLS. The only dry weather exceedances were for total and fecal coliform. A map showing dry weather exceedances for all sites in the WMA is presented in Figure 11-3. Only fecal coliform concentrations exceeded objectives during both the 2004-2005 wet weather monitoring and the 2004 dry weather monitoring efforts. Table 11-10. Sweetwater River 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* Total Coliform 2 4 3.16 Fecal Coliform 1 4 0.28 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-20 11.2.3 TIEs Chollas Creek and Sweetwater River were identified as potential TIE candidate sites based on toxicity to Hyalella and Selenastrum, respectively. Both stations expressed slight toxicity during one of the three storm events (October 17, 2004). The NOEC was determined to be the 50% dilution of the storm water, while the EC50 concentrations were calculated to be greater than 100% for Chollas Creek and 99.4% for Sweetwater River. This indicates that there was only a slight decrease in the response (survival or cell growth) of the 100% storm water sample relative to the test control treatment. TIE testing operates on the removal of certain components of the sample which may be contributing to the sample (i.e. metals, non-polar organic compounds). The toxicity of the sample should be sufficient enough to identify those procedures which effectively remove the toxicity. Since the toxicity was not consistent among events and was relatively slight, a standard TIE would not likely determine the cause. 11.2.4 Summary and Conclusions The Chollas sub-watershed within the Pueblo San Diego watershed, the Sweetwater watershed, and the Otay watershed comprise the San Diego Bay WMA. The differences in water quality between these watersheds likely reflect the differences in land uses. The Chollas sub-watershed is highly urbanized. Water quality problems within Chollas Creek are typical of heavily residential and commercial areas with frequent water quality exceedances of turbidity, TSS, bacterial indicators, total and dissolved copper and total zinc. Aside from bacterial indicators and total dissolved solids, Sweetwater River does not have persistent water quality problems. Even though none of the pesticides analyzed had a statistically significant decreasing trend, there were not any pesticide exceedances during 2004-2005 in Chollas Creek or Sweetwater River. During the 2003-2004 monitoring season, Diazinon concentrations exceeded objectives at both MLS. Chlorpyrifos has not been detected nor exceeded the WQO in either Chollas Creek or Sweetwater over the past two monitoring seasons. The Otay watershed is one of the three least populated watersheds in the San Diego Region but has not been sampled during this monitoring program since the majority of runoff is captured in the Otay reservoir and is prevented from flowing downstream. 11.3 Stream Bioassessment Stream bioassessment in the San Diego Bay WMA included three urban affected monitoring sites. One site was in Chollas Creek at the Federal Blvd. off-ramp from Highway 94. Two sites were in Sweetwater River; the upstream site was at the Highway 94 overcrossing in Rancho San Diego, and the downstream site was along Bonita Road, downstream of Willow Street. The Sweetwater River site at Highway 94 was not sampled in October 2004 due to dry conditions. 11.3.1 Results and Discussion Chollas Creek at Federal Blvd.: CC-FB The Chollas Creek monitoring site had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Poor and Very Poor in October 2004 and May 2005, respectively (Table 11-11) (See Section 3.2 for details on the sampling approach). The taxa richness was 13 and 16 different taxa per survey, and there were 2 different EPT taxa per survey. There were no organisms collected that were highly intolerant to impairment, and taxa that are highly tolerant comprised 49% and 9% of the community in October and May, respectively. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-21 Table 11-11. Selected Biological Metrics and Physical Measures of the San Diego Bay WMA. San Diego Bay Watershed Management Area Chollas Creek at Federal Blvd. (CC-FB) Sweetwater River at Highway 94 (SR-94) Sweetwater River at Bonita Road (SR-WS) Survey Oct-04 May-05 May-05 Oct-04 May-05 Index of Biotic Integrity/ Qualitative Rating 17 Poor 10 Very Poor 8 Very Poor 1 Very Poor 5 Very Poor Metrics Taxa Richness 13 16 12 9 11 EPT Taxa (mayflies, stoneflies, and caddisflies) 2 2 3 1 2 % Intolerant Taxa 0% 0% 0% 0% 0% % Tolerant Taxa 49% 9% 2% 5% 48% Average Tolerance Value 7.1 5.4 5.5 6 6.9 % Collector Filterers +Collector Gatherers 68% 96% 98% 99% 98% Physical Measures Elevation 220 40 Physical Habitat Score 147 136 125 127 107 Riffle Velocity (ft/sec) 1.2 1.0 0.9 1.9 1.6 Substrate Composition Silt 32% 8% Sand 2% 12% 66% 53% 57% Gravel 17% 18% 20% 5% Cobble 81% 52% Boulder 5% 2% Roots 27% 30% Bedrock/Solid 13% Water Quality Temperature ºC 20.5 22.5 21.9 16.3 19.4 pH 7.7 7.6 8.0 7.6 7.8 Specific Conductance (ms/cm) 4.635 2.382 0.757 3.830 3.523 Relative Chlorophyll (μg/L) 2.3 0.2 4.1 6.3 10.0 The physical habitat of the site was sub-optimal. The bioassessment sampling reach was located in a natural streambed and the substrate consisted primarily of smooth, layered cobble. There was little riparian canopy and the riffles were very shallow, and the bank vegetation was mostly native sage scrub. Specific conductance values were 4.635 mS/cm in October 2004 and 2.382 mS/cm in May 2005, indicating a level of total dissolved solids that would likely prevent the colonization of sensitive organisms. Values for pH were 7.7 and 7.6 in the October and May surveys, respectively. In the October survey, the benthic community was dominated by Chironomid midges, Ostracods, and the snail, Physa (Table 11-12). In the May survey, the community was dominated by the Baetid mayflies, Baetis and Fallceon quilleri, which comprised 60 percent of the community, and the black fly, Simulium. In October 2004, as in October 2003, the site again supported unusually high numbers of soldier flies San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-22 (MEC-Weston 2005). Percent filterers plus collector gatherers increased from 68% of the community in October to 96% of the community in May (Table 11-11). Table 11-12. San Diego Bay WMA Community Summary. Taxon Common Name Percent Composition Tolerance Value Functional Feeding Group Chironomidae non-biting midges 31% 6 Collector Gatherer/Filterer Ostracoda seed shrimp 27% 8 Collector Gatherer Physa aquatic snail 20% 8 Scraper Caloparyphus/ Euparyphus soldier fly 7% 8 Collector Gatherer Oct-04 Argia dancer damselfly 6% 7 Predator Baetis minnow mayfly 40% 5 Collector Gatherer Fallceon quilleri minnow mayfly 20% 4 Collector Gatherer Simulium black fly 18% 6 Collector Filterer Chironomidae non-biting midges 8% 6 Collector Gatherer/Filterer Chollas Creek at Federal Blvd. (CC-FB) May-05 Physa aquatic snail 3% 8 Scraper Simulium black fly 38% 6 Collector Filterer Oligochaeta earth worm 20% 5 Collector Gatherer Chironomidae non-biting midges 20% 6 Collector Gatherer/Filterer Fallceon quilleri minnow mayfly 12% 4 Collector Gatherer Sweetwater River at Highway 94 (SR-94) May-05 Baetis minnow mayfly 7% 5 Collector Gatherer Simulium black fly 43% 6 Collector Filterer Chironomidae non-biting midges 36% 6 Collector Gatherer/Filterer Oligochaeta earth worm 15% 5 Collector Gatherer Ostracoda seed shrimp 3% 8 Collector Gatherer Oct-04 Procambarus crayfish 1% 6 Shredder Simulium black fly 38% 6 Collector Filterer Ostracoda seed shrimp 30% 8 Collector Gatherer Hyalella amphipod 17% 8 Collector Gatherer Chironomidae non-biting midges 9% 6 Collector Gatherer/Filterer Sweetwater River at Bonita Road (SR-WS) May-05 Baetis minnow mayfly 2% 5 Collector Gatherer The Chollas Creek mass loading station was located approximately two miles downstream of the bioassessment site, and water quality measures from storm water may have contained constituents that did not affect the bioassessment site. Constituents of concern identified during storm water sampling that would have a negative impact on the biological community included total suspended solids, turbidity, and the metals copper, lead, and zinc (Table 11-12). Some toxicity to Ceriodaphnia and Hyalella from storm water has been detected at the MLS, and this may indicate that the water quality could prevent the colonization of highly sensitive organisms (Hyalella has a tolerance value of 8). Sweetwater River at Highway 94: SR-94 The upstream Sweetwater River monitoring site had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Very Poor for the May 2005 survey (Table 11-11). The taxa richness San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-23 was relatively low, with 12 different taxa collected and with 3 different EPT. There were no organisms collected that are highly intolerant to impairment, and there were few taxa that are highly tolerant, which comprised 2% of the community. The physical habitat of the site was marginal. The substrate was primarily consolidated fine particulate clay/sand, with some treefall and a small amount of rock from the rip rap lined bridge abutment of Highway 94. The site had a dense willow riparian canopy, but the low gradient of the reach made for flat riffles with slow current velocity. Water quality measures indicated slightly better conditions than in the past, with specific conductance of 0.757 ms/cm and a pH of 8.0. The benthic community was dominated by the black fly, Simulium; Oligochaete earthworms, and Chironomid midges (Table 11-12). Baetid mayflies comprised 19% of the community. The Sweetwater River mass loading station was too spatially disconnected from the Highway 94 site to correlate any of the storm water information with the benthic community. Sweetwater River along Bonita Road: SR-WS The downstream Sweetwater River monitoring site had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Very Poor for both the October 2004 and May 2005 surveys, and was the lowest rated site in the county in the October Survey (Table 11-11). The taxa richness was low, with 9 and 11 different taxa per survey, and there was 1 EPT taxon in October, and 2 EPT taxa in May. There were no organisms collected that were highly intolerant to impairment, and taxa that are highly tolerant comprised 5% of the community in October 2004 and 48% of the community in May 2005. The in-stream habitat of the site was marginal, although the site had a dense willow riparian zone with good canopy cover over the stream. The substrate was primarily unconsolidated gravel and sand, with some emergent vegetation and tree roots providing additional stable substrate. Water quality measures indicated an increase in total dissolved solids from the upstream site, with specific conductance values of 3.830 ms/cm in October and 3.523 ms/cm in May. The high specific conductance in May was in contrast to most of the county sites, which tended to have lower than usual conductance values (MEC-Weston 2005). Relative chlorophyll values were slightly higher than most sites in the region, with 6.3 and 10.0 µg/L, and values for pH were 7.6 and 7.8 for the October and May surveys, respectively. The benthic community was dominated by the black fly, Simulium, in both surveys (Table 11-12). Chironomid midges and Oligochaetes were also abundant in October, and Ostracods and the amphipod, Hyalella, were abundant in May. Collector filterers plus collector gatherers heavily dominated both surveys comprising 99% of the community in October 2004 and 98% of the community in May 2005. The Sweetwater River mass loading station was located less than one mile upstream of the bioassessment site with little additional urban runoff sources, and water quality measures may be correlated with the site. Constituents of concern identified during storm water sampling that would have a negative impact on the biological community included total dissolved solids and turbidity (Table 11-8). Metals were generally not detected. Toxicity to Ceriodaphnia and Hyalella from storm water has been an issue at the site, and this may indicate that the water quality could prevent the colonization of highly sensitive organisms. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-24 11.3.2 Summary and Conclusions Three monitoring sites were sampled in the San Diego Bay WMA. One site was in Chollas Creek at Federal Blvd., and two sites were in Sweetwater River, at Highway 94 in Rancho San Diego and along Bonita Road. Chollas Creek had Index of Biotic Integrity ratings of Poor and Very Poor, and was rated higher than many of the urban sites in the county. Both Sweetwater River sites were rated Very Poor during both surveys. The Sweetwater River monitoring sites were low-gradient, depositional reaches of the river, and the specific conductance increased substantially between the upstream and downstream site. These characteristics likely had negative affects on the IBI scores. 11.4 Ambient Bay and Lagoon Monitoring Program 11.4.1 Results and Discussion 11.4.1.1 Phase I Results and Discussion Sediment samples were collected in Sweetwater River Estuary for the ABLM Program on June 2, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 11-5. The median grain size of sediments sampled in Sweetwater River Estuary was extremely variable, ranging from 5.1μm to 167.13μm (Table 11-13). However, the mean percentage of fine grained sediments (55.58%) was the third highest of the sites sampled in Phase I, following Buena Vista Lagoon (58.27%) and Los Peñasquitos Lagoon (55.73%). There were no strong differences in grain size distribution between the inner, middle, and outer strata. Sediments at most of the sites had a fairly even distribution between the sand, silt, and clay fractions with the inner stratum sites having a slightly higher content of sand. TOC values were also fairly similar among the sites, ranging from 0.57% to 1.48% (Table 11-13). The three sites that ranked highest in the Phase I assessment were found in each of the three strata (1M-1, 2L-1, and 3R-1). Figure 11-5. Map of Phase I site locations in Sweetwater River Estuary. Sites with yellow triangles were selected for Phase II assessment. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-25 Table 11-13. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Sweetwater River Estuary. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II SRE-1L-1 0.01 42.0 44.5 13.5 50.2 30.5 58.02 0.64 6 2 8 SRE-1M-1 0.00 19.0 37.2 43.9 8.5 NC 81.05 1.17 8 6 14 * Yes SRE-1R-1 1.51 45.7 28.3 24.5 51.44 13.80 52.80 0.73 5 3 8 SRE-2L-1 0.07 17.5 34.8 47.7 5.1 NC 82.42 1.48 9 9 18 * Yes SRE-2M-2 0.00 23.5 41.7 34.8 18.52 4.98 76.52 1.04 7 4 11 SRE-2R-1 0.88 57.5 22.3 19.2 77.4 16.50 41.57 1.05 3 5 8 SRE-3L-1 0.27 61.4 19.5 18.8 96.3 23.2 38.34 1.29 2 7 9 SRE-3M-1 0.00 82.96 7.4 9.6 167.13 123.95 17.04 0.57 1 1 2 SRE-3R-1 0.04 47.5 18.4 34.1 38.5 8.38 52.48 1.30 4 8 12 * Yes Mean of all Sites 0.31 44.11 28.23 27.35 57.02 31.61 55.58 1.03 NC = Not calculable (%silt + %clay > 84%) 11.4.1.2 Phase II Results and Discussion The three sites selected in Sweetwater River Estuary as part of Phase I were sampled in Phase II on July 13, 2004. Sediments from sites 1M-1, 2L-1 and 3R-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 11-14. Table 11-14. Summary of chemistry, toxicity, and benthic community structure in Sweetwater River Estuary. CHEMISTRY* TOXICITY* BENTHIC COMMUNITY Analyte ERL ERM Result ERM-Q Percent Survival Index 1M- 1 2L-1 3R-1 Mean Total METALS (mg/kg) Abundance 483 1189 1168 947 2840 Antimony NA NA <1.74 NA Richness 36 43 34 38 73 Arsenic 8.2 70 4.67 0.067 Diversity 2.51 2.30 2.15 2.32 -- Cadmium 1.2 9.6 <0.174 NA Evenness 0.70 0.61 0.61 0.64 -- Chromium 81 370 24.5 0.066 Dominance 6 4 5 5 -- Copper 34 270 33.1 0.123 Lead 46.7 218 22.9 0.105 Nickel 20.9 51.6 8.57 0.166 Selenium NA NA <1.74 NA Zinc 150 410 129 0.315 Mean ERM-Q 0.140 79 % Not Significantly different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-26 Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, six metals were detected above the detection limit in Sweetwater River Estuary: arsenic, chromium, copper, lead, nickel, and zinc (Table 11-14). All of these metals were also found in all the other embayments assessed in the ABLM Program. Concentrations of metals were low and none exceeded their respective ERL or ERM values. The same metals were detected during the 2003 ABLM program with the addition of cadmium. None of these metals exceeded their respective ERL or ERM values in 2003. There were no PAHs, PCBs, or pesticides found above the detection limit in Sweetwater River Estuary during the 2004 program. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was 0.140. This value exceeded the threshold of 0.10. This is similar to the 2003 results where the mean ERM quotient was 0.198. Sediments with mean ERM-Q values above this threshold have a higher probability of producing adverse biological effects than those with mean ERM-Qs below the threshold (Long et al. 1998). Toxicity. The percent survival of E. estuarius exposed to Sweetwater River Estuary sediments in a 10- day acute toxicity test was 79 % (Table 11-14).This suggests that Sweetwater River Estuary sediments were not toxic to the test organisms. During the 2003 ABLM program toxicity was observed, but the source of toxicity was unknown. Benthic Community Structure. A total of 2,840 organisms were collected from Sweetwater River Estuary, representing 73 taxa (Table 11-14). Total taxa abundance and richness were very high, third only to Mission Bay and Oceanside Harbor. This is similar to the 2003 ABLM program where Sweetwater River Estuary was among the top two sites for taxa richness and abundance with 1,927 organisms collected, representing 57 taxa. Site 2L-1 in the middle stratum had greater abundance and taxa richness than Sites 1M-1 and 3R-1. However, diversity, evenness, and dominance were greatest at Site 1M-1, near the mouth of the River. Based on these indices, the benthic community structure in Sweetwater River had a rank of 3, where 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. As in 2003, the barley snail, Barleeia sp., dominated the benthic community in Sweetwater River Estuary during the 2004 ABLM program, accounting for 27.7% (39.2% in 2003) of all the animals collected (Table 11-15). The polychaete worm, Mediomastus sp., was the second most abundant, accounting for 13.2% of the total abundance. The third most abundant species were the Nematodes with 11.9% of the population. Table 11-15. Dominant infaunal species found in the Sweetwater River Estuary during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Barleeia sp Mollusca 786 27.7 Mediomastus sp Polychaeta 376 13.2 SRE Nematoda Minor Phyla 338 11.9 * Values were calculated from the total of all sites assessed. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-27 Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Sweetwater River Estuary were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM-Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 11-6. For Sweetwater River Estuary, the relative ranks were eight for chemistry, nine for toxicity, and three for benthic community structure. 11.4.1.3 Summary and Conclusions Sediments in Sweetwater River Estuary were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size). These sites included Site 1M-1 in the outer Stratum, 2L-1 in the middle stratum, and 3R-1 in the inner stratum. In Phase II of the assessment, sediments from these three sites were composited and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that six of the nine metals assessed were found in Sweetwater River sediments, including arsenic, chromium, copper, lead, nickel, and zinc. The mean ERM-Q for Sweetwater River Estuary was the fourth highest of any embayment assessed in the ABLM Program. No ERL or ERMs were exceeded. There were no PAHs, PCBs, or pesticides found above the detection limit in Sweetwater River Estuary during the 2004 program. The percent survival of test organisms exposed to Sweetwater River Estuary sediments was the third lowest (i.e., highest toxicity) of any of the embayments assessed although not significantly different from that of the Control. The benthic community indices suggested that the biotic community in the Sweetwater River Estuary had a rank of 3 (where a value of 1 represents the lowest combined index score and 12 the highest). The infaunal community was dominated by a genus of barley snail, followed by polychaete worms and Nematodes. The relative ranks for the Sweetwater River Estuary compared to the other embayments of the ABLM Program were eight for chemistry, nine for toxicity and three for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Sweetwater River Estuary had an overall rank of eight. During the 2003 ABLM program the Sweetwater River Estuary had an overall rank of ten. A decrease in overall ranking indicates an increase in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 11.5 WMA Assessment The San Diego Bay WMA is comprised of multiple watersheds which are monitored as part of the San Diego County Urban Runoff Program. Among these are the Chollas sub-watershed within the Pueblo San Diego watershed and the Sweetwater watershed. Each of these watersheds is assessed separately. 0 1 2 3 4 5 6 7 8 9 10 Chemistry Toxicity Benthos RankingFigure 11-6. Relative rankings for sediment in Sweetwater River. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-28 Chollas Sub-watershed The Chollas sub-watershed was assessed utilizing chemistry and toxicity data collected during storm events from a single MLS on Chollas Creek, chemistry data collected from four dry weather monitoring sites upstream of the MLS, and IBI scores generated at one bioassessment site. The watershed management area assessment methods presented in Section 3.4 (Table 3-17) were applied to these data to determine which constituents were of concern and to develop a high, medium, or low frequency of occurrence. The results of this assessment are presented in Table 11-16. For the Pueblo San Diego watershed, eight constituents were found to have a high frequency of occurrence and are listed below as constituents of concern. All of these constituents received a rating of three diamonds based on Criterion No. 1 with the exception of Diazinon and dissolved copper which were based on Criteria No. 3. These include: • Total Coliform • Fecal Coliform • Enterococcus • Turbidity • Total copper • Total zinc • Diazinon • Dissolved copper Two constituents were found to have a medium frequency of occurrence and received two diamonds based on Criterion No. 6. These constituents include: • COD • Total suspended solids Five constituents were found to have a low frequency of occurrence and received one diamond. These constituents include: • Ammonia, • Orthophosphate • MBAS • BOD • Total lead Ammonia, MBAS and orthophosphate received one diamond based on Criterion No. 8, while BOD and total lead received one diamond based on Criterion No. 9. BOD and COD are unique among the COC assessed in the storm water program because they provide an indirect measure of the total oxidizable material available in the water column due to other factors, including anthropogenic contaminants as well as natural processes (as opposed to other methods which only provide results for the specific analyte tested). The presence of BOD or COD above their respective water quality criteria indicate the presence of other contaminants that may have caused the exceedance. Thus, management actions aimed at reducing BOD or COD may be most effective if the source or sources of the elevated levels are addressed directly. In this way, a reduction in BOD or COD levels would be a by-product of actions taken against more easily rectified COC. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-29 Table 11-16. Constituent exceedances in the Chollas sub-watershed. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters pH 0 0 0 0 0 0 1 33 1 8 0 0 - - BOD 1 33 1 33 2 67 1 33 5 42 NA NA ♦ 9 COD 2 67 1 33 2 67 1 33 6 50 NA NA ♦♦ 6 Surfactants (MBAS) 1 33 0 0 0 0 0 0 1 8 1 25 ♦ 8 Total Dissolved Solids 0 0 0 0 0 0 1 33 1 8 NA NA - - Total Suspended Solids 2 67 2 67 1 33 3 100 8 67 NA NA ♦♦ 6 Turbidity 3 100 3 100 3 100 3 100 12 100 3 75 ♦♦♦ 1 Nutrients Ammonia 0 0 0 0 0 0 0 0 0 0 1 25 ♦ 8 Orthophosphate NA NA NA NA NA NA NA NA NA NA 2 50 ♦ 8 Total Phosphorus 1 33 0 0 0 0 0 0 1 8 NA NA - - Bacteriological Total Coliform 3 100 3 100 3 100 3 100 12 100 2 50 ♦♦♦ 1 Fecal Coliform 3 100 2 67 3 100 3 100 11 92 1 25 ♦♦♦ 1 Enterococcus 3 100 3 100 3 100 3 100 12 100 2 50 ♦♦♦ 1 Pesticides Chlorpyrifos 3 100 2 67 0 0 0 0 5 42 0 0 - - Diazinon 3 100 3 100 3 100 0 0 9 75 1 25 ♦♦♦ 3 Malathion NA NA 0 0 0 0 1 33 1 8 NA NA - - Total Metals Copper 3 100 3 100 3 100 3 100 12 100 NA NA ♦♦♦ 1 Lead 0 0 0 0 3 100 0 0 3 25 NA NA ♦ 9 Zinc 3 100 3 100 3 100 2 67 11 92 NA NA ♦♦♦ 1 Dissolved Metals Copper 3 100 3 100 0 0 0 0 6 50 1 25 ♦♦♦ 3 Zinc 0 0 2 67 0 0 1 33 3 25 0 0 - - Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 96- hour 3 100 1 33 0 0 0 0 4 33 NA NA No Ceriodaphnia 7-day survival 3 100 2 67 0 0 0 0 5 42 NA NA No Ceriodaphnia 7-day reproduction 3 100 1 33 0 0 1 33 5 42 NA NA No Hyalella 96-hour 2 67 1 33 2 67 1 33 6 50 NA NA Yes Bioassessment EVIDENCE OF BENTHIC ALTERATION? Chollas Creek (DS) NA Poor Very Poor Poor Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-30 The watershed assessment process does not indicate cadmium as a COC, which has previously been considered a potential COC primarily because of its inclusion on the SWRCB 303(d) list. It is expected that cadmium will be removed from the 303(d) list as it has been recommended for delisting by the SWRCB in September, 2005. The triad decision matrix for evidence of persistent toxicity is based on greater than 50% of the bioassay tests conducted on any species showing NOEC values less than 100%. Although Ceriodaphnia dubia 7-day reproduction did show toxicity in one event during the 2004-2005 monitoring season it did not indicate persistent toxicity as in previous years based on the methods in Section 3.4. The species, Hyalella azteca, was found to have a frequency of occurrence of exactly 50%. To be conservative, Chollas Creek was listed as showing evidence of persistent toxicity based on the Hyalella 96-hour toxicity test. IBI scores resulting from bioassessment monitoring on Chollas Creek varied between poor and very poor throughout the monitoring period. Conservatively, this indicates there is evidence of benthic alteration. Figure 11-7 summarizes the number of occurrences of water quality exceedances for six categories of constituents. Categories include conventionals, nutrients, bacteria, pesticides, metals, and toxicity. The stacked bars were developed using the number of exceedances found from values in Table 11-16 for each constituent category. The overall number of exceedances of the water quality objectives at the Chollas sub-watershed exhibit a continued reduction in the overall number of exceedances since 2001. It appears that a reduction in toxic effects has contributed the greatest to this reduction, and nutrients are no longer a contributing source in this assessment technique. Chollas Creek Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 11-7. Stacked bar chart of the number of wet weather exceedances of constituent groups in Chollas Creek. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-31 Evaluation of long-term scatterplots for Chollas Creek presented in Appendix C indicate a statistically significant increasing trend for turbidity (R2=0.12) which is listed as a high frequency COC and is also an indicator of BMP concern. Although nitrite has not exceeded the water quality objective during the past four monitoring seasons, a slight but statistically significant increasing trend (R2=0.15) is evident, yet well below the WQO. Nitrite should continue to be monitored to ensure the parameter does not become a COC. A statistically significant decreasing trend was evident for total lead (R2=0.14) although there were three exceedances of the water quality objective during the 2003-2004 monitoring season. Sweetwater Watershed The Sweetwater watershed was assessed utilizing chemistry and toxicity data collected during storm events from a single MLS, chemistry data collected from five dry weather monitoring sites upstream of the MLS, and IBI scores generated at two bioassessment sites. The watershed management area assessment methods presented in Section 3.4 (Table 3-17) were applied to these data to determine constituents of concern and to develop a high, medium, or low frequency of occurrence and the applicable criteria for these constituents. The results of this assessment are presented in Table 11-17. For the Sweetwater watershed, one constituent was found to have a high frequency of occurrence and was given three diamonds based on Criteria No. 1. This constituent was: • Fecal coliform One constituent was found to have a medium frequency of occurrence and was assigned two diamonds based on Criteria No. 6. This constituent was: • Total dissolved solids Four constituents were found to have a low frequency of occurrence and were assigned one diamond. These constituents include: • Total coliform • Turbidity • Enterococcus • Diazinon Toxicity tests conducted on Selenastrum have shown evidence of toxicity in 50% of the cumulative sampling events. Conservatively, there is evidence of persistent toxicity in the Sweetwater watershed. IBI scores resulting from bioassessment monitoring at the Sweetwater River Bonita Rd. site have consistently indicated a rating of Very Poor. The cumulative IBI score from the Hwy 94 site was Very Poor as well. Therefore, there is evidence of benthic alteration within the Sweetwater watershed. Figure 11-8 summarizes the number of water quality exceedances for six categories of constituents. Categories include conventionals, nutrients, bacteria, pesticides, metals and toxicity. The stacked bars were developed using number of exceedances from values in Table 11-17 for each constituent category. The overall number of exceedances of the water quality objectives in the Sweetwater watershed has slightly declined over the last four monitoring seasons, and although pesticides and bacteriological groups declined since the previous year, toxicity and conventional exceedances increased. Evaluation of scatterplots for Sweetwater River presented in Appendix C indicate a statistically significant decreasing trend for Diazinon (R2=0.34). There were no statistically significant increasing trends evident for any of the parameters monitored at the Sweetwater River MLS, although COD and TSS exceeded their respective water quality objectives for the first time during the 2004-2005 monitoring season. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-32 Table 11-17. Constituent exceedances in the Sweetwater watershed. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters BOD 0 0 0 0 1 33 0 0 1 8 NA NA - - COD 0 0 0 0 0 0 1 33 1 8 NA NA - - Total Dissolved Solids 2 67 1 33 3 100 2 67 8 67 NA NA ♦♦ 6 Total Suspended Solids 0 0 0 0 0 0 1 33 1 8 NA NA - - Turbidity 1 33 2 67 0 0 1 33 4 33 0 0 ♦ 9 Bacteriological Total Coliform 1 33 1 33 3 100 0 0 5 42 2 50 ♦ 8 Fecal Coliform 2 67 3 100 3 100 2 67 10 83 1 25 ♦♦♦ 1 Enterococcus 1 33 2 67 2 67 1 33 6 50 0 0 ♦ 9 Pesticides Chlorpyrifos 1 33 2 67 0 0 0 0 3 25 0 0 - - Diazinon 2 67 3 100 1 33 0 0 6 50 0 0 ♦ 9 Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 96- hour 1 33 1 33 0 0 1 33 3 25 NA NA No Ceriodaphnia 7-day survival 1 33 1 33 0 0 1 33 3 25 NA NA No Ceriodaphnia 7-day reproduction 2 67 1 33 0 0 2 67 5 42 NA NA No Selenastrum 96-hour 3 100 1 33 1 33 1 33 6 50 NA NA Yes Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? Sweetwater River, at HWY 94 Poor NA Very Poor Very Poor Very Poor NA Sweetwater River, at Bonita Rd. (DS) Very Poor Very Poor Very Poor Very Poor Very Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. DS = Downstream of MLS San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-33 Sweetwater River Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 11-8. Stacked bar chart of the number of wet weather exceedances of constituent groups in Sweetwater watershed. Triad Decision Matrix The triad decision matrix combines the occurrence of COCs determined from the wet weather MLS monitoring and dry weather monitoring upstream of the MLS with the toxicity and bioassessment results to determine possible conclusions about the condition of the watershed and provide possible actions for future monitoring or assessment. The triad decision matrix is presented separately for the Chollas sub- watershed and the Sweetwater watershed in the following sections. Chollas Sub-watershed Table 11-18 summarizes the results of the watershed assessment and concludes that degradation of Chollas Creek is occurring due to pollutant loading even though the total number of COC exceedances has been declining. The high frequency COCs in Chollas Creek are bacterial indicators, Diazinon, turbidity, total and dissolved copper, and total zinc. However, bacterial indicators are not considered in the triad decision making process because they are not believed to influence toxicity responses in bioassay test organisms. Chollas Creek is in a TMDL for Diazinon and with the banned retail sale of Diazinon going into effect on January 1, 2005 the continued decreasing trend should continue to the point that Diazinon may not be a COC in future monitoring events. With the eventual implementation of the copper, lead, and zinc TMDL in Chollas Creek these COCs will continue to be monitored and will eventually be addressed under the new permit. Toxicity identification evaluations should be considered if continued toxicity is observed in future monitoring events to determine the contaminant(s) most likely responsible for toxicity effects. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-34 Table 11-18. Decision matrix results for the Chollas Sub-watershed. Chemistry Toxicity Benthic Community Possible Conclusion(s) Possible Actions or Decisions Persistent exceedance of water quality objectives Evidence of persistent toxicity (conservative at 50%) Indications of alteration Evidence of current pollution-induced degradation 1) Continue to perform TIE to identify contaminant(s) of concern based on TIE metric. 2) Continue monitoring to gather long-term trend information. Sweetwater Watershed Only fecal coliform was identified as having a high frequency of occurrence. However, bacterial indicators are not considered in the triad decision making process because they are not believed to influence toxicity responses in bioassay test organisms. Analyses have shown evidence of persistent toxicity and indications of benthic alteration in the Sweetwater WMA. A TIE was not performed during the 2004-2005 monitoring season. TIEs should be continued (as recommended in Table 11-19) to identify the source or sources of toxicity and should be initiated at the time the bioassay analyses are started. Table 11-19. Decision matrix results for the Sweetwater Watershed. Chemistry Toxicity Benthic Community Possible Conclusion(s) Possible Actions or Decisions No persistent exceedance of water quality objectives Evidence of persistent toxicity (conservative at 50%) Indications of benthic alteration Toxicity may be caused by contaminants not currently monitored for or synergistic effects of multiple constituents at low levels. The benthic alterations may be due to physical habitat disturbances. 1) Continue to perform TIE to identify contaminant(s) of concern based on TIE metric. 2) Continue monitoring to gather long-term trend information. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the San Diego Bay WMA The water quality priority ratings presented in Table 11-20 are based on the methodology presented in the BLTEA report (WESTON, MOE, & LWA 2005) and are presented in the Methods Section 3.4. Constituent groups and stressor groups are given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicate that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on current results presented in this 2004-2005 annual report and data from the following programs: • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Co-permittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303d Listing San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-35 Table 11-20. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the San Diego Bay WMA Priority Ratings* Constituent Groups Stressor Groups Watersheds/ Sub-watersheds Percentage of Total Area Heavy Metals Organics Oil and Grease Sediments Pesticides Nutrients Gross Pollutants Bacteria/ Pathogens Benthic Alterations Toxicity San Diego Bay WMA 100% C D D A B C C B B C Point Loma HA (908.10) 2% A D D D B D D A A A San Diego Mesa HA (908.20) 9% A A D A A D B A A A National City HA (908.30) 2% C D C D A C B A A A Lower Sweetwater HA (909.10) 11% C D D A B D D A A C Middle Sweetwater HA (909.20) 19% D D D B B D D B B C Upper Sweetwater HA (909.30) 22% D D D B B C D B B C Coronado HA (910.10) 2% C D D D B C D A D D Otay Valley HA (910.20) 10% B D C D A C B A D D Dulzura HA (910.30) 22% D D D D D B D D D D Notes: * = Rating Calculated Based on Area Weighted Averages of Score Value from the sub-watershed areas. ** = Priority Level (Highest-A to Lowest-D) The purpose of the BLTEA ratings is to identify water quality priorities within a watershed based on weighted averages of the sub-watershed ratings. Because it is a weighted average, larger sub-watersheds will have a greater influence in the overall watershed rating. Sediment was rated as the highest priority constituent (A) for the San Diego Bay WMA followed by pesticides, bacteria, and benthic alterations which were given B ratings. All other constituents were given either a C or D rating. The Point Loma sub-watershed, which accounts for only 2% of the San Diego Bay WMA, had high priority (A) ratings for heavy metals, bacteria, benthic alteration, and toxicity. The San Diego Mesa HA, which includes the Chollas Creek sub-watershed and accounts for 9% of the San Diego Bay WMA, had high priority (A) ratings for heavy metals, organics, sediments, pesticides, bacteria, benthic alteration, and toxicity. The National City sub-watershed, which accounts for only 2% of the San Diego Bay WMA, had high priority (A) ratings for pesticides, bacteria, benthic alteration, and toxicity. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-36 The Lower Sweetwater sub-watershed, which accounts for 11% of the San Diego Bay WMA, had high priority (A) ratings for sediments, bacteria, and benthic alteration. The Coronado sub-watershed, which accounts for only 2% of the San Diego Bay WMA, had a high priority (A) rating only for bacteria. The Otay Valley sub-watershed, which accounts for 10% of the San Diego Bay WMA, had high priority (A) ratings for pesticides and bacteria. The Middle Sweetwater sub-watershed, which accounts for 19% of the San Diego Bay WMA, and the Upper Sweetwater sub-watershed, which accounts for 22% of the San Diego Bay WMA, each had only B priority ratings for sediments, pesticides, bacteria, and benthic alteration. The Dulzura sub-watershed accounts for 22% of the San Diego Bay WMA and had a B priority rating only for nutrients. A regional evaluation and description of the BLTEA is presented in the Regional Assessment Section 13. The complete tables used to calculate the ratings are presented in Appendix G. 11.6 Conclusions and Recommendations Chollas Sub-watershed The Chollas sub-watershed within the Pueblo San Diego watershed drains a very densely populated, urban area. Nearly 65% of the drainage area is residential and another 17% is commercial. Turbidity, all three indicator bacteria, Diazinon, total and dissolved copper, and total zinc were identified as high frequency of occurrence COC. Medium frequency of occurrence COC were identified for COD, and TSS, followed by BOD, MBAS, ammonia, orthophosphate, and total lead which were identified as low frequency of occurrence COC. The benthic community impacts and stream habitat impairments may be a result of elevated COC or physical alterations to the riparian corridor. Since the EPA has banned the retail sale of Diazinon and Chlorpyrifos, and with the increased public outreach and education regarding the handling of pesticides in general, a decreasing trend for these compounds should continue. Continued monitoring of the organophosphate compounds should show an overall decrease in the number of WQO exceedances and concentrations over time with the expectation that residual public supply and use will eventually be exhausted. However, the pesticide manufacturer’s shift to synthetic pyrethroids does warrant concern and monitoring should be considered for these analytes. The recommendations for the Chollas Sub-watershed are to continue monitoring to gather long-term trend information and to perform TIEs to determine the likely source of toxicity in Chollas Creek. Sweetwater watershed The Sweetwater watershed drainage area consists of 50% vacant or undeveloped land, 30% residential and only 10% commercial. The contrast in land use compared to Chollas Creek may likely be the reason for better observed (based on data assessed) water quality in Sweetwater River. Only fecal coliform was identified as a high frequency of occurrence COC within Sweetwater River. TDS was identified as a medium frequency of occurrence COC, followed by turbidity, total coliform, enterococcus, and Diazinon, which were identified as low frequency of occurrence COC. The bioassessment monitoring identified Sweetwater River as having a Very Poor IBI score and was the lowest rated site in the county in the October Survey. In the ABLM program, the results of the chemistry assessment indicated that six of the nine metals assessed were found in Sweetwater River sediments. None of the six metals detected above the reporting limit exceeded its respective ERL or ERM value. The mean ERM quotient was 0.140 which exceeded the threshold value of 0.10. Sweetwater River Estuary ranked eight for chemistry, nine for toxicity, and three for benthic community structure relative to the other embayments assessed. San Diego Bay WMA SECTION 11 2004-2005 Urban Runoff Monitoring Report 11-37 Compared to the other embayments in the 2004 ABLM program, Sweetwater River Estuary had an overall rank of eight. The relative quality in the Sweetwater River Estuary increased in 2004 compared with the 2003 ranking. The recommendations for the Sweetwater watershed are to continue monitoring to gather long-term trend information and conduct TIEs in parallel to toxicity tests to determine the likely source of toxicity in Sweetwater River. BLTEA ratings for the San Diego Bay WMA For the San Diego Bay WMA, sediment was given a high priority (A) rating based on the BLTEA rating method followed by pesticides, bacteria, and benthic alterations which were given a B rating. The BLTEA findings are similar to the WMA assessments for both Chollas Creek and Sweetwater River. Turbidity, bacteria and Diazinon had a high frequency of occurrence in Chollas Creek, while bacteria had a high frequency of occurrence in Sweetwater River. There was evidence of benthic alteration in both sub-watersheds. The information provided from the triad matrix results used in conjunction with the BLTEA ratings can assist the jurisdictions in making informed decisions in developing their WURMP programs. The two reports also allow for an evaluation of where data gaps exist and where efforts should be targeted. Utilizing the BLTEA rating methods for future data evaluations would also allow for long term BMP effectiveness assessment. Incorporation of additional useable data from other third party sources such as the San Diego Coastkeeper, other non-profit organizations, and other POTWs would also help to increase the confidence of the BLTEA ratings and overall WMA assessments. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-1 12.0 TIJUANA RIVER WATERSHED MANAGEMENT AREA 12.1 Monitoring Site Descriptions The Tijuana River watershed management area includes the Tijuana River watershed (HU 911.00), which is the largest of the San Diego watersheds covering over 1.1 million acres (Figure 12-1). The watershed is divided by the U.S. / Mexico border with just over 27% lying within the San Diego Region. The watershed is comprised of the following hydrologic areas: Tijuana Valley, Potrero, Barrett Lake, Monument, Morena, Cottonwood, Cameron, and Campo. Major water bodies include the Tijuana River, Cottonwood Creek, and the Tijuana River Estuary. Mexico governs the majority of the Tijuana River watershed (73%) with the remaining areas belonging to the United States. Undeveloped areas account for 58% of U.S. lands, with another 25% devoted to parks. Much of the land classified as undeveloped is used for low intensity cattle and goat grazing (SANDAG 1998). Population within the U.S. areas of the watershed is sparse with the major population centers located at Campo and San Ysidro. The cities of Tecate and Tijuana are the major population centers on the Mexican side of the watershed. The population for the entire watershed is approximately one million (San Diego County 2002). The Tijuana River is formed by two drainage networks that merge in the City of Tijuana, then flow across the U.S. border into the Tijuana River Estuary, and finally the Pacific Ocean. The Tijuana River watershed suffers from a wide variety of water quality problems. Major impacts to the watershed include surface water quality degradation, trash, sedimentation, eutrophication, habitat degradation and loss, flooding, erosion, and invasive species. Constituents that have been placed on the SWRCB 2002 303(d) list for water bodies throughout the watershed include bacteria indicators, eutrophic conditions, trace elements, pesticides, solids, synthetic organics, low dissolved oxygen, and trash. The sources of the pollutants are varied including urban runoff, sewage spills, industrial discharges, agriculture, livestock and domestic animals, and septic systems (San Diego County 2002). The RWQCB has 303(d) listed the Pacific Ocean Shoreline for bacterial indicators (RWQCB 2003). The Tijuana River watershed provides a variety of beneficial uses and sensitive habitats, including the Tijuana River Estuary, which is a National Estuarine Sanctuary (Table 12-1). The major aquifer in the watershed is the Lower Tijuana River Valley Basin. Annual precipitation varies from less than 10.5 inches near the coast to more than 22.5 inches in the inland areas (Figure 12-1). The Tijuana River (TJR) mass loading station is located under the Hollister Street Bridge in San Diego, downstream from the International Boundary and Water Commission's diversion structure and treatment plant. During periods of low flow the river is diverted through the treatment plant. The River flows freely once the water level rises over the diversion structure. The Tijuana River at the sampling site is an unimproved channel. The River flows through Tijuana, Mexico and runoff contributions come from both Mexico and the United States. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-2 Figure 12-1. Tijuana River Watershed Management Area. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-3 Table 12-1. Beneficial uses within the Tijuana River watershed. Beneficial Uses Inland Surface Waters Coastal Waters (a) Reservoirs and Lakes Ground Waters Municipal and Domestic Supply z z z Agricultural Supply z z z Industrial Service Supply z z z Industrial Process Supply z z Navigation Commercial & Sport Fishing z Freshwater Replenishment z z Contact Water Recreation z z z Non-Contact Water Recreation z z z Biological Habitats of Special Significance z Warm Freshwater Habitat z z Cold Freshwater Habitat z z Estuarine Habitat z Wildlife Habitat z z z Rare, Threatened, or Endangered Species z z z Marine Habitat z Migration of Aquatic Organisms z Aquaculture Shellfish Harvesting z Spawning, Reproduction, and/or Early Development (a) Tijuana River Estuary Source: Basin Plan September 8, 1994 (Tables 2-2, 2-3, 2-4, 2-5) Stream Bioassessment monitoring in the Tijuana River WMA has occurred at three urban affected sites. The upstream sites are located in Cottonwood Creek at the USGS Gauging station on Highway 94, and in Campo Creek at the Highway 94 crossing in the town of Campo. The Cottonwood Creek site does not flow in the dry season, but the Campo Creek site does, and will likely be sampled regularly in the future. The downstream monitoring reach is between Dairy Mart Road and the International Boundary in San Ysidro. This reach is low gradient with a substrate of unconsolidated sand and cobble. Pollution from the City of Tijuana has a substantial impact here, and the stream bed is highly susceptible to erosion. Due to river diversion to the International Wastewater Treatment Plant (IWTP), flow at this site does not occur during the dry season. There was adequate flow in May of 2005, and the site was sampled for the second time since the current program began. The Tijuana River flows into the Tijuana River Estuary before it enters the ocean. The Estuary is located in the southwestern corner of San Diego County, between the City of Imperial Beach and Tijuana, Mexico. The Estuary is large, encompassing 1,780 acres of wetland habitat, all of which is contained within the Tijuana River National Estuarine Sanctuary (Coastal Conservancy 2000). The Estuary consists of three major areas: the main stem in the center of the Estuary, a northern arm known as Tijuana Slough, and a southern arm, which lies in Border Field State Park. The northern and southern arms roughly parallel the beach in a series of narrow, shallow channels. Two of the three sites selected to be assessed in the Ambient Bay and Lagoon Monitoring Program were located in the mainstream Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-4 (Figure 12-1). The other was located in a small side channel adjacent to the mainstream. The Tijuana River is the primary source of fresh water to the Estuary, although an unconfined aquifer underlying the river valley can contribute fresh water periodically. The ocean inlet is relatively shallow and restricts the tidal prism of the Estuary, but there are no anthropogenic obstructions to flow. Raw sewage has been discharged to the River and side channels intermittently for over fifty years and water quality has been a concern. The Tijuana River Estuary is listed on the SWRCB 2002 303(d) list for several constituents, including bacteria indicators, eutrophic conditions, lead, low dissolved oxygen levels, nickel, pesticides, thallium, and trash (Table 12-2). Table 12-2. Water bodies on the SWRCB 303(d) list in the Tijuana River watershed. Water Body Name Hydrologic Sub Area (HSA) HSA # Pollutant/Stressor Tijuana River Tijuana Valley 911.11 Bacteria Indicators, Eutrophic conditions, Low Dissolved Oxygen, Pesticides, Solids, Synthetic Organics, Trace Elements, Trash Tijuana River Estuary Tijuana Valley 911.11 Bacteria Indicators, Eutrophic conditions, Lead, Low Dissolved Oxygen, Nickel, Pesticides, Thallium, Trash Pacific Ocean Shoreline, Tijuana HU Tijuana Valley 911.11 Bacteria Indicators Pine Valley Creek (Upper) Monument 911.41 Enterococci Source: SWRCB 2003 12.2 Storm Water Monitoring Summary Three storm events were monitored at the MLS on Tijuana River during the 2004-2005 storm season. These storm events occurred on October 27, 2004, February 11 and 18, 2005. The results from these storms are discussed in the following section (12.2.1) and presented in Table 12-3. A comparison of these results to previous years is provided in Section 12.2.2. 12.2.1 2004-2005 Results Two conventional constituents exceeded water quality criteria for all three storms monitored, including total suspended solids (TSS) and turbidity. Additionally, there were WQO exceedances for BOD, COD, and surfactants during the February 11, 2005 storm event. All three of the bacterial indicators, total and fecal coliform, and enterococcus, had extremely elevated densities during all three storm events. Fecal coliform consistently exceeded the Basin Plan objective of 400 MPN/100 mL with maximum observed densities of 5,000,000 MPN/100 mL. Table 12-3. Analytes measured at the Tijuana River mass loading station.1/29/02 2/17/02 3/17/02 11/8/02 2/11/03 2/25/03 11/12/03 1/25/04 2/3/04 10/27/04 2/11/05 2/18/05Electrical Conductivity umhos/cm 1610 2300 2490 1664 1830 2890 1174 1471 25000 430 1449 1075Oil and Grease mg/L 15 USEPA Multi-Sector General Permit 4 2 1 3.93 1.23 8.56 9.1 2.38 6.44 2 4.69 5.28 0% 0.28pH pH Units 6.5-8.5 Basin Plan 7.4 8.1 7.6 7.308.517.32 7.43 7.76 7.96 7.75 7.65 7.43 9% 0.09BacteriologicalEnterococci MPN/100 mL 170,000 500,000 17,000 2,400,000 50,000 30,000 500,000 5,000,000 2,400,000 800,000 3,000,000 1,700,000Fecal Coliform MPN/100 mL 4000 Basin Plan800000c 300000c 300000c 5,000,000 500,000 16,000,000 1,700,000 800,000 800,000 5,000,000 2,400,000 2,200,000100% 745.83Total Coliform MPN/100 mL 1,700,000 800,000 1,100,000 >16,000,000 1,300,000 16,000,000 3,000,000 2,800,000 1,300,000 5,000,000 5,000,000 9,000,000Wet ChemistryAmmonia As N mg/L 8 7.2 6.4 5.22 8.00 10.40 1.9 8.05 6.4 4.5 8.14 3.28Un-ionized Ammonia as Nμg/L 25 (a) Basin Plan39.2 636 63.016.7127 12424.186.1 42.778% 5.15Biological Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit 27.346.2 33.33.5686.423.270.9 72.5 98.623.96726.6 58% 1.61Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit 95263 122 152 257113319 217 9037619750 67% 1.92Dissolved Organic Carbon mg/L30.6 35.7 23.4 45.8 29.3 14.4 39.2 20.3 8.65Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit2.2 2.9 2.281.75 1.90 0.93 1.563.411.99 1.69 1.73 1.26 33% 0.98Nitrate As N mg/L 10 Basin Plan 1.6 0.8 1.1 3.12 0.72 0.44 8.75 1.72 1.5 4.08 1.97 2.12 0% 0.23Nitrite As N mg/L 1 Basin Plan 0.341.440.6 0.98 0.37 0.13 0.42 0.59 0.34 0.11 0.37 <0.05 8% 0.48Surfactants (MBAS) mg/L 0.5 Basin Plan <0.53.3 0.70.32.0<0.1 <0.51.7<0.5 <0.50.70.5 42% 1.71Total Dissolved Solids mg/L 2500 Basin Plan by watershed 737 1080 965 885 883 794 650 476 491 400 938 664Total Kjeldahl Nitrogen mg/L 10.3 12 16.8 9.5 13.6 22.0 16.4 19.8 19.5 19.4 18.2 10.4Total Organic Carbon mg/L47.5 51.0 18.6 41.8 69.1 72.9 55.5 25.7 23.5Total Phosphorus mg/L 2 USEPA Multi-Sector General Permit3.2 4.7 2.52 2.37 2.04 2.381.83.41 2.971.732.71.74 75% 1.32Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit24048176 160971070 590 120 128 7440 890 290083% 11.55Turbidity NTU 20 Basin Plan48.419.954.7 141 72.8 1000 383 90.6 3270 4540 60.2 53792% 42.57PesticidesChlorpyrifosμg/L 0.02 CA Dept. of Fish & Game0.06 0.08 0.09 0.168<0.03* <0.03* <0.010.085<0.01 <0.01 <0.01 <0.01 42% 2.24Diazinonμg/L 0.08 CA Dept. of Fish & Game0.74 0.53 0.57 0.372 0.506 0.339 0.584 0.276 0.907<0.010.394 0.16992% 5.62Malathionμg/L 0.43 CA Dept. of Fish & Game1.00 0.880.271.46 0.7880.284 <0.010.498<0.01 56% 1.34HardnessTotal Hardness mg CaCO3/L 970 352 286 279 334 395 328 308 417 702 376 350Total MetalsAntimony mg/L 0.006 Basin Plan 0.003 0.003 0.003 <0.002 0.002 0.003 <0.005 <0.006 <0.005<0.005 <0.005 <0.0050% 0.42Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan 0.007 0.008 0.006 0.005 0.008 0.018 0.011 0.0090.0550.013 0.01 0.0038% 0.26Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 0.001 <0.001 0.0050.001 <0.001 <0.0010% 0.05Chromium mg/L (b) CTR (Cr VI) 0.02 0.013 0.006 <0.005 0.006 0.049 0.026 <0.005 0.189<0.005 0.014 0.0060% 0.01Copper mg/L (b) 40 CFR 131 0.028 0.013 0.016 0.008 0.0210.053 0.0580.020.1970.017 0.038 0.04325% 0.84Lead mg/L (b) 40 CFR 131 0.025 0.005 0.009 0.004 0.011 0.045 0.048 0.007 0.2780.0090.057 0.056Nickel mg/L (b)/0.1 40 CFR 131/ Basin Plan 0.044 0.033 0.028 0.003 0.021 0.040 0.029 0.0130.1010.051 0.015 0.0190% 0.02Selenium mg/L 0.02 40 CFR 131 <0.002 0.008 <0.002 <0.004 <0.004 <0.004 <0.005 <0.005 0.005<0.005 <0.005 <0.0050% 0.14Zinc mg/L (b) 40 CFR 131 0.120 0.041 0.062 <0.020 0.077 0.269 0.288 0.0561.530.1650.3920.33717% 0.72Dissolved MetalsAntimony mg/L (e) 40 CFR 131 <0.002 <0.002 0.002 0.004 0.003 0.004 <0.005 <0.006 <0.005<0.005 <0.005 <0.005Arsenic mg/L 0.34 (c) 40 CFR 131 0.005 0.004 0.005 0.010 0.008 0.005 0.003 0.006 0.006<0.002 <0.002 <0.0020% 0.00Cadmium mg/L (b) 40 CFR 131 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.001 <0.001 <0.0010% 0.03Chromium mg/L (b) 40 CFR 131 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.005 <0.005 <0.0050% 0.00Copper mg/L (b) 40 CFR 131 0.008 <0.005 <0.005 0.0110.0600.013 0.005 0.01 0.0050.005 <0.005 <0.0058% 0.24Lead mg/L (b) 40 CFR 131 <0.002 0.002 <0.002 0.003 <0.002 <0.002 <0.002 <0.002 <0.002<0.002 0.003 <0.002Nickel mg/L (b) 40 CFR 131 0.033 0.028 0.024 0.018 0.017 0.013 0.003 0.011 0.0070.006 0.009 0.0060% 0.01Selenium mg/L 0.02 (d) 40 CFR 131 <0.002 <0.002 <0.002 <0.004 <0.004 <0.004 <0.005 <0.005 <0.005<0.005 <0.005 <0.0050% 0.10Zinc mg/L (b) 40 CFR 131 <0.020 0.026 0.057 0.062 0.130 0.046 <0.02 <0.02 <0.02<0.02 0.023 <0.020% 0.10Frequency Above WQOMean Ratio to WQO2003-04 2004-052001-02 2002-03SOURCEANALYTE UNITS WQOGeneral / Physical / Organic Table 12-3. Analytes measured at the Tijuana River mass loading station.1/29/02 2/17/02 3/17/02 11/8/02 2/11/03 2/25/03 11/12/03 1/25/04 2/3/04 10/27/04 2/11/05 2/18/05Frequency Above WQOMean Ratio to WQO2003-04 2004-052001-02 2002-03SOURCEANALYTE UNITS WQOToxicityCeriodaphnia 96-hr LC50 (%) 10036.11 17.36 32.99 19.5 10.15 32.98 14.36 18.95 17.68 50 25 25100% 4.79Ceriodaphnia 7-day survival NOEC (%) 10012.5 12.5 12.5 12.5 6.25 12.5 6.25 12.5 6.25 25 25 25100% 9.00Ceriodaphnia 7-day reproduction NOEC (%) 1006.25 12.5 6.25 12.5 6.25 12.5 6.25 12.5 12.5 50 25 25100% 9.50Hyalella 96-hr NOEC (%) 100 100 100 100 100 10050 5010050100 100 100 25% 0.50Selenastrum 96-hr NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 0% 0.00SourcesUSEPA Federal Register Document 40 CFR Part 131, May 18, 2000.USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Table 3 - ParameteSiepmann and Finlayson 2000.Basin Plan, September 8, 1994.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.Shaded text – exceeds water quality objective.* Indicates detection limit exceeds water quality objective.(e) USEPA has not published an aquatic life criterion value.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000Blank spaces have been verified and no data is available due to changes in the monitoring program. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-7 Un-ionized ammonia-N concentrations exceeded water quality objectives during the last two storm events monitored during the 2004-2005 wet weather season. Total phosphorus concentrations exceeded the water quality objective during the February 11, 2005 storm event. Nitrate, nitrite and TKN did not exceed the water quality objectives during any storm event in 2004-2005. Diazinon concentrations exceeded water quality objectives during two of the storms and Malathion concentrations exceeded water quality objectives during one storm event. Chlorpyrifos was not detected during any of the storms monitored in 2004-2005. Total lead concentrations exceeded water quality objectives during two storm events and total zinc exceeded the WQO during one storm event. All other metals, including metals in the dissolved state, were either not detected or were below their respective water quality objectives during the 2004-2005 storm events. All of the storms sampled during 2004-2005 (October 27, 2004, February 11 and 18, 2005) from Tijuana River showed toxicity to Ceriodaphnia (See Section 3.1.6.2 for details on toxicity testing). The NOEC for 96-hour survival was 50%, 25%, and 25% of the test sample for the three storms; the NOEC for 7-day survival was 25% of the test sample for each of the storms, and the NOEC for 7-day reproduction was 50%, 25%, and 25% of the test sample for the three storm events. No toxicity to Hyalella or Selenastrum was observed in any of the Tijuana River samples collected for the three storm events. 12.2.2 Relationships/Analyses The four conventional constituents mentioned in the previous section (BOD, COD, TSS and turbidity) are persistent constituents of concern in the watershed. Over the last four years of monitoring, TSS concentrations have exceeded WQOs 10 times (83%); turbidity levels have exceeded WQOs 11 times (92%); BOD concentrations have exceeded WQOs 7 times (58%), and COD concentrations have exceeded WQOs 8 times (67%). TSS concentrations have been increasing significantly (R2=0.34) over time at the Tijuana MLS, while there has been a significant decrease in TDS concentrations (R2=0.35). MBAS was less persistent during the last three years, only exceeding water quality objectives during 5 of the last 12 storms monitored (42%). These elevated levels of COC are consistent with levels expected of surface waters contaminated with untreated wastewater. Nutrients that regularly exceed water quality objectives in the watershed include un-ionized ammonia-N (58% exceedance) and total phosphorus (75% exceedance). Dissolved phosphorus has exceeded water quality objectives in 4 out of 12 storms, however, only one of these exceedances has occurred in the last two years. All bacterial indicators show persistent, extremely elevated density levels in all 12 storms monitored during the past 4 years. These elevated densities are also consistent with the presence of untreated wastewater. There is a significant increasing trend in enterococcus densities (R2=0.40). Pesticides have also been consistently present in the water. Diazinon has been detected above water quality objectives in 11 out of 12 storms monitored since 2001 (92%). Chlorpyrifos has exceeded objectives in five storms (42% of the storms monitored); only one of these five has occurred since 2003. Additional monitoring is required to determine if this is a decreasing trend. Malathion has only been monitored for in the last nine storms, but has exceeded objectives in five of these (56% of the time), including one in 2004-2005. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-8 Metals have not been observed persistently above WQOs in the Tijuana River watershed. Of the nine metals analyzed for in total and dissolved form, only total copper, total lead and total zinc have exceeded the water quality objectives more than once. Total copper concentrations exceeded the criteria in 3 out of 12 storms monitored (25%), and total lead and zinc concentrations exceeded the WQO in 2 out of 12 storms monitored (17%). Decreasing trends have been observed for dissolved arsenic (R2=0.33) and dissolved nickel (R2=0.79). Because all of the Ceriodaphnia tests showed toxicity in all 12 storm events, the chi-square test used in the other watersheds was not appropriate for the Tijuana River. COC that were above water quality objectives consistently may have contributed to the observed toxicity. These COC include Diazinon, turbidity, and TSS. Chi-square tests showed significant relationships between concentrations of total copper and Hyalella 96-hour (p=0.003). In order to illustrate the magnitude of the water quality exceedances for 2004-2005, the ratio of water quality results to the WQOs were plotted for several of the most common constituents of concern. The results are shown in Figure 12-2. The largest ratios of exceedance were for fecal coliform, which exceeded the WQO by 1250 times during the October 27, 2004 storm, by 600 times during the February 11, 2005 storm and by 550 times during the February 18 storm. Turbidity and TSS concentrations also had large ratios of exceedance. Turbidity ratios of exceedance ranged from 3 to 227 times the WQO and TSS ratios ranged from 9 to 74 times the WQO. There were also noticeable ratios of exceedance for Diazinon (4.9 times the WQO) and ammonia (3.5 times the WQO). The average magnitude of water quality exceedances was also determined for each constituent by calculating the mean ratio of water quality results to the WQOs from all storm events from October 2001 through April 2004. Mean ratios are illustrated in Figure 12-2. The largest average exceedance for the period of record was for fecal coliform (728 times the WQO). Other notable average exceedances were for turbidity (28 times the WQO), Ceriodaphnia survival (9.8 times the WQO), and Diazinon and ammonia (6.7 times the WQO). In addition to wet weather monitoring discussed above, there are seven sites in the Tijuana River WMA where water quality is monitored during dry weather. Of these, five sites are located upstream of the MLS on Tijuana River (See Section 3.4 for details on dry weather sampling). Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-9 TDSTSSTurbidityBODCODFecal ColiformAmmoniaNitrateTotal PhosphorusChlorpyrifosDiazinonMalathionTotal CopperTotal ZincCeriodaphnia 96-hrCerio. 7-day survivalCerio. 7d reproductionHyalella 96-hrSelenastrum 96-hr0 2 4 6 8 10 400 800 1200 1600 Ratio to WQOMean Ratio (Oct 01 to Apr 04) 10/27/04 2/11/05 2/18/05 Above WQO Figure 12-2. Tijuana River water quality ratios. Table 12-4 lists exceedances of dry weather action levels and the ratios of exceedance for COC that were measured during the 2004 dry weather monitoring program for dry weather stations upstream of the MLS. The only dry weather exceedance was for turbidity. A map showing dry weather exceedances for all sites in the WMA is presented in Figure 12-3. Turbidity WQOs were also exceeded during the wet weather monitoring in 2004-2005. Table 12-4. Tijuana River WMA 2004 Dry Weather Exceedance Matrix. Constituent Number of Exceedances Number of Samples Collected Average Ratio of Exceedance* St. Dev. Ratio of Exceedance Turbidity 2 4 1.17 1.02 * Average ratio of exceedance is equal to the average concentration for all samples collected divided by the Water Quality Objective. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-10 Figure 12-3. Tijuana River WMA dry weather exceedance map. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-11 12.2.3 TIEs Tijuana River was identified as a TIE candidate site based on the Triad Decision Matrix. Toxicity was observed in Ceriodaphnia in all three 2004-2005 storm events. TIE testing was conducted on the February 11 and 18, 2005 samples. These investigations were inconclusive due to the loss of toxicity in the unmanipulated sample at the time of testing. Heavy particulate load within the sample may have ameliorated the toxic effects of the sample by binding to the contaminants. Non-polar organic compounds were identified in the 2002-2003 and 2003-2004 TIE testing. Diazinon was the suspect contaminant in these testing periods as determined by methanol fractionation procedures. Given the presence of Diazinon exceeding the WQO during the February storm events, it is probable that Diazinon was a contributor to the toxicity of the Tijuana River samples to Ceriodaphnia. Diazinon (log Kow=3.81) has a low solubility and a tendency to bind to organic matter and sediments (Ladaa et al. 1998). The persistence of this and other non-polar organic compounds may have been reduced by the high solids content of the Tijuana River samples. 12.2.4 Summary and Conclusions Constituents most prevalent in Tijuana River that pose the greatest concern are typical of conditions found with untreated wastewater. BOD, COD, TSS, turbidity, and nutrients (un-ionized ammonia-N and total phosphorus) consistently exceeded water quality objectives. Although total coliform and enterococci do not have corresponding water quality objectives, they consistently have highly elevated densities and are also indicative of conditions found with untreated wastewater. In addition, pesticides are also prevalent in elevated concentrations. Diazinon, in particular, has exceeded water quality objectives in 11 of the last 12 storms and has been identified as the likely cause of toxicity in the Tijuana River. 12.3 Stream Bioassessment Stream bioassessment monitoring in the Tijuana River WMA was conducted at a single site in October 2004; Campo Creek at the Highway 94 overcrossing in the town of Campo. Three sites were sampled in May 2005; Campo Creek, Tijuana River at Dairy Mart Road, and a reference site in Wilson Creek at Lyons Valley Road, upstream of Barrett Lake. This was the first time Wilson Creek has been sampled in this program. The Tijuana River and Wilson Creek sites could not be sampled in October 2004 due to dry conditions. 12.3.1 Results and Discussion Campo Creek monitoring site: CC-C The Campo Creek monitoring site had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Very Poor for both surveys (Table 12-5) (See Section 3.2 for details on the sampling approach). There were 17 and 12 different taxa collected, including 1 and 2 different EPT taxa in October and May, respectively. There were no organisms collected that are highly intolerant to impairment, and the percent tolerant taxa comprised 80% of the community in October 2004 and 7% of the community in May 2005. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-12 Table 12-5. Selected Biological Metrics and Physical Measures of the Tijuana River WMA. Tijuana River Watershed Management Area Campo Creek in Campo (CC-C) Tijuana River- Dairy Mart Road (TJ-DM) Wilson Creek Reference Site at Lyons Valley Road (REF-WC) Survey Oct-04 May-05 May-05 May-05 Index of Biotic Integrity/ Qualitative Rating 6 Very Poor 4 Very Poor 17 Poor 36 Fair Metrics Taxa Richness 17 12 7 14 EPT Taxa (mayflies, stoneflies, and caddisflies) 1 2 0 6 % Intolerant Taxa 0% 0% 0% 5% % Tolerant Taxa 80% 7% 10% 0% Average Tolerance Value 7.4 6.0 6.2 5.6 % Collector Filterers +Collector Gatherers 87% 93% 92% 92% Physical Measures Elevation 2550 2200 Physical Habitat Score 93 128 98 156 Riffle Velocity (ft/sec) 0.4 1.0 1.3 0.8 Substrate Composition Silt 66% 2% 10% Sand 7% 35% 7% 8% Gravel 7% 41% 13% 37% Cobble 20% 8% 40% 55% Boulder 14% Bedrock/Solid 30% Water Quality Temperature ºC 12.8 14.6 17.8 17.9 pH 7.2 7.6 7.1 8.1 Specific Conductance (ms/cm) 0.906 1.190 1.584 0.363 Relative Chlorophyll (μg/L) 6.8 6.1 4.7 0.8 Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-13 In October 2004, the physical habitat of the monitoring reach was marginal due to slow riffle velocity and a predominance of anoxic, silty substrate. There was a moderate amount of cobble, boulder, and emergent vegetation that provided some stable habitat. In May 2005, in-stream conditions had improved, and it appeared that the heavy winter rains had scoured out much of the silty deposits, which decreased from 66% in October to 2% of the streambed in May. There was a good willow canopy over the stream, but the riparian zone was very narrow due to the proximity of Highway 94, as well as residential and agricultural land uses. Specific conductance was relatively low at 0.906 mS/cm in October and 1.190 mS/cm in May. Values for pH were 7.2 and 7.6 for the October and May surveys, respectively. The benthic community was seasonally variable. In October the benthic community was dominated by Sphaeriid clams, Ostracods, and Oligochaetes (Table 12-6). In May, the dominant taxa were Chironomid midges, the black fly, Simulium, and the minnow mayfly, Baetis. The predatory damselfly, Argia, was present in relatively high numbers, and two individuals of the sensitive caddisfly, Oxyethira, were collected. Campo Creek was the only non-reference site in the San Diego County program where Sphaeriid clams, the mite, Lebertia, and the water penny beetle, Psephenus falli, were collected. Table 12-6. Tijuana River WMA Community Summary. Taxon Common Name Percent Composition Tolerance Value Functional Feeding Group Sphaeriidae clam 35% 8 Collector Filterer Ostracoda seed shrimp 31% 8 Collector Gatherer Oligochaeta earth worm 12% 5 Collector Gatherer Hyalella amphipod 8% 8 Collector Gatherer Campo Creek in Campo (CC-C) Oct-04 Physa aquatic snail 4% 8 Scraper Chironomidae non-biting midges 64% 6 Collector Gatherer/Filterer Simulium black fly 18% 6 Collector Filterer Baetis minnow mayfly 5% 5 Collector Gatherer Oligochaeta earth worm 5% 5 Collector Gatherer Campo Creek in Campo (CC-C) May-05 Physa aquatic snail 4% 8 Scraper Chironomidae non-biting midges 73% 6 Collector Gatherer/Filterer Psychoda moth fly 10% 10 Collector Gatherer Pericoma/ Telmatoscopus moth fly 7% 4 Collector Gatherer Culicoides biting midge 5% 6 Predator Tijuana River at Dairy Mart Road (TJ-DM) May-05 Muscidae common fly 2% 6 Predator Simulium black fly 54% 6 Collector Filterer Chironomidae non-biting midges 31% 6 Collector Gatherer/Filterer Baetis minnow mayfly 7% 5 Collector Gatherer Rhyacophila free living caddisfly 2% 0 Predator Wilson Creek Reference site at Lyons Valley Road (REF-WC) May-05 Plecoptera stonefly (immature) 2% 1 Predator/Shredder Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-14 The Tijuana River mass loading station was too spatially disconnected from Campo Creek to correlate any of the storm water information with the benthic community. Tijuana River at Dairy Mart Road: TJ-DM The Tijuana River monitoring site had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Poor for the May 2005 survey (Table 12-5). The IBI score was 17, making this one of the higher rated urban sites in the county program. This ranking is not representative of the true quality of the benthic community of the site, which indicated that the site is actually severely degraded. Taxa richness and abundance were the lowest of any site in the county, and there were no EPT taxa collected. Overall abundance was extremely low, with a total of 84 individuals collected from three combined samples, and a population density of about 5 organisms per square foot of substrate. One of the replicate samples had a total of four individual organisms. Individual IBI metric scores for percent tolerant taxa and percent non-insect taxa were not truly representative, and the investigators have noted other instances when the Southern California IBI scoring system may be subject to inaccuracies when organism abundance is exceptionally low. Information from the mass loading stations have indicated high levels of pesticides in the river and exceedances for total dissolved solids, nutrients, and some metals, and there has been consistent toxicity to Ceriodaphnia (Table 12-3). Additionally, bacteria levels were extremely high, indicating probable high levels of organic pollution. These indicators of very poor water quality confirm the assertion that the IBI score for the site is higher than the actual benthic community quality. Wilson Creek Reference Site at Lyons Valley Road: REF-WC The Wilson Creek reference monitoring site had a benthic macroinvertebrate community with an Index of Biotic Integrity rating of Fair (Table 12-5). Taxa richness was moderate, with 14 different taxa collected, including 6 different EPT taxa. Organisms collected that are highly intolerant to impairment comprised 5% of the community, and there were no highly tolerant taxa collected. The physical habitat of the monitoring reach was optimal with a good oak canopy and a substrate dominated by small layered cobble. Specific conductance was low with a value of 0.363 mS/cm and pH was 8.1. The benthic community was dominated by the black fly, Simulium, and Chironomid midges (Table 12-6). Together, these two taxa accounted for 85% of the community. The remainder of organisms collected at the site, although in relatively small numbers, included a majority of highly intolerant stonefly and caddisfly taxa, and predaceous beetle taxa. There were also relatively high numbers of the very sensitive dobsonfly larvae (Neohermes), a large predatory insect that may live three years in its aquatic larval form (Usinger 1956). The presence of these intolerant organisms indicated very good water quality in the stream. The Tijuana River mass loading station was too spatially disconnected from Wilson Creek to correlate any of the storm water information with the benthic community. 12.3.2 Summary and Conclusions Three stream bioassessment monitoring sites were sampled in the Tijuana River WMA. One site in Campo Creek was sampled in October and May. A site in the Tijuana River at Dairy Mart Road and a Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-15 reference site in Wilson Creek at Lyons Valley Road were sampled in May 2005. The Index of Biotic Integrity rating for the Campo Creek site was Very Poor, but there were several organisms collected that were otherwise found only at reference sites, and specific conductance was very low. The Tijuana River site was rated Poor, but the investigators in this study feel that the IBI score was much higher than the actual benthic community quality. The Wilson Creek reference site was rated Fair, and the presence of many highly intolerant organisms indicated very good water quality at the site. 12.4 Ambient Bay and Lagoon Monitoring 12.4.1 Results and Discussion 12.4.1.1 Phase I Results and Discussion Sediment samples were collected in Tijuana River Estuary for the ABLM Program on June 10, 2004 (See Section 3.3 for details on the sampling approach). The nine sites sampled as part of the Phase I assessment are shown in Figure 12-4. The median grain size ranged from 2.15 μm at Site 2L-1 to 408.9 μm at Site 3L-1 (Table 12-7). Although this range is fairly broad, the median grain size was fairly consistent among sites, except Site 2L-1. The percentage of fine grained sediments at Site 2L-1 was more than twice that found at all the other sites in the Tijuana Estuary. The TOC content was also very high in sediments at Site 2L-1compared to the other sites. Sediments at Site 2L-1 consisted primarily of clay, while sediments at all the other sites monitored in the Estuary consisted predominantly of sand. Sediments with the highest proportion of sand were found at all three outer strata sites and at Site 2M-1 in the middle stratum. These four sites also had some of the lowest TOC contents. Site 2L-1 received the highest rank sum of the nine sites sampled in Tijuana River Estuary due to the high percentage of fine grained sediments and elevated TOC levels found at this site (Table 12-7). Three sites with the highest summed ranks in the Phase I assessment were found in each of the three strata ( 1L-2, 2L-1, and 3M-1) Figure 12-4. Map of Phase I site locations in Tijuana River Estuary. Sites with yellow triangles were selected for Phase II assessment. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-16 Table 12-7. Results of Phase I sediment analyses and subsequent ranking for Phase II site selection at Tijuana River Estuary. TOC and Grain Size Distribution in Phase I Ranking for Phase II Sampling Site Gravel (%) Sand (%) Silt (%) Clay (%) Median (μm) Mean (μm) Fines (%) TOC (%) Fines Rank TOC Rank Rank Sum Highest Rank Phase II TRE-1L-2 0.00 72.9 7.49 19.59 203 27 27.08 0.57 7 6 13 * Yes TRE-1M-1 0.00 98.1 1.08 0.79 265 261 1.87 0.10 1 2 3 TRE-1R-2 0.02 87.9 3.34 8.70 285 251 12.03 0.39 3 3 6 TRE-2L-1 0.00 13.4 29.1 57.5 2.15 NC 86.57 1.28 9 9 18 * Yes TRE-2M-1 0.00 95.2 2.53 2.24 161 158 4.77 0.09 2 1 3 TRE-2R-1 0.00 83.8 6.8 9.4 131 111.6 16.20 0.40 4 4 8 TRE-3L-1 0.11 82.3 6.4 11.2 408.9 156.3 17.55 1.05 5 8 13 TRE-3M-1 0.12 66.1 14.5 19.3 97.0 20.9 33.82 0.67 8 7 15 * Yes TRE-3R-1 0.16 81.8 6.10 12.0 407 145.4 18.07 0.51 6 5 11 Mean of all Sites 0.05 75.74 8.58 15.63 217.73 141.27 24.22 0.56 St. Dev. 0.07 25.39 8.60 16.96 137.45 88.90 25.40 0.40 NC = Not calculable (%silt + %clay > 84%) 12.4.1.2 Phase II Results and Discussion The three sites selected in Tijuana River Estuary as part of Phase I were sampled in Phase II on July 6, 2004. Sediments from Sites 1L-2, 2L-1 and 3M-1 were composited and analyzed for chemistry, toxicity, and benthic community structure. The results are summarized in Table 12-8. Sediment Chemistry. Sediments from each of the 12 coastal embayments in the ABLM Program were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. Of these, seven metals that were common to all the embayments were detected above the detection limit in Tijuana River Estuary: arsenic, cadmium, chromium, copper, lead, nickel, and zinc (Table 12-8). Concentrations of all metals were low, well below their respective ERL values. The same metals were detected during the 2003 ABLM program with the exception of cadmium. All of the metal concentrations during the 2003 program were low and well below their respective ERL values. There were no PAHs, PCBs, or pesticides found above the detection limit in Tijuana River Estuary. The mean ERM quotient, which is a measure of the cumulative effects of the COC for which ERMs are available, was 0.128. This value was above the threshold of 0.10. Sediments with mean ERM-Q values above this threshold have a higher probability of producing adverse biological effects (Long et al. 1998). During the 2003 ABLM program the mean ERM quotient was 0.052 and was well below the threshold of 0.10. Toxicity. The percent survival of E. estuarius exposed to Tijuana River Estuary sediments in a 10-day acute toxicity test was 97% (Table 12-8). Percent survival was not significantly different from that of the Control (99%), suggesting that Tijuana River Estuary sediments were not significantly toxic to the test organisms. This is similar to the results from the 2003 ABLM program where no toxicity was observed. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-17 Table 12-8. Summary of chemistry, toxicity, and benthic community structure in the Tijuana River Estuary. CHEMISTRY* TOXICITY* BENTHIC COMMUNITY Analyte ERL ERM Result ERM- Q Percent Survival Index 1L- 2 2L- 1 3M- 1 Mean St. Dev. Total METALS (mg/kg) Abundance 475 189 319 327 143 983 Antimony NA NA <1.74 NA Richness 31 18 18 22.3 7.51 39 Arsenic 8.2 70 5.36 0.077 Diversity 1.75 2.05 1.67 1.8 0.20 NA Cadmium 1.2 9.6 0.374 0.039 Evenness 0.51 0.71 0.58 0.6 0.10 NA Chromium 81 370 28.4 0.077 Dominance 3 4 3 3.3 0.58 NA Copper 34 270 18 0.067 Lead 46.7 218 19.9 0.091 Nickel 20.9 51.6 11.1 0.215 Selenium NA NA <1.74 NA Zinc 150 410 98.4 0.240 Mean ERM- Q 0.128 97 % Not Significantly Different from Control * Analysis performed on composite samples from the three sites. NA-Not applicable Bold – exceeds ERL or ERM value Benthic Community Structure. A total of 983 organisms were collected from Tijuana River Estuary, representing 39 taxa (Table 12-8). During the 2003 ABLM program a total of 1,354 organisms were collected, representing 33 taxa. Taxa abundance and richness were greatest at Site 1L-2 in the outer stratum during the 2004 ABLM program, but all of the other benthic community structure indices were greatest at Site 2L-1. This site was located in a small side channel of the middle stratum. Based on these indices, the benthic community structure in Tijuana River Estuary ranked intermediate compared to the other embayments assessed in the ABLM Program with an accumulative rank of six where 1 represents the healthiest community with the lowest combined index score and 12 the least-healthy community. The benthic community in Tijuana River Estuary was dominated by the polychaete worm, Streblospio benedicti, which accounted for 38.2 % of the community (Table 12-9). Second in abundance was the gammarid amphipod, Grandidierella japonica, which accounted for 27.3 %. Another polychaete worm, Polydora nuchalis, made up 6.9% of the sampled population. During the 2003 ABLM program the Tijuana River Estuary was co-dominated by three taxa: the polychaete worm Pseudopolydora paucibranchiata, which accounted for 28.1% of the community, Protothaca sp., a molluscan genus that includes the littleneck clam, which accounted for 23.8%, and Grandidierella japonica, which accounted for 22%. Table 12-9. Dominant infaunal species found in Tijuana River Estuary during the 2004 ABLM Program. Embayment Taxa (Species) Higher Taxa Abundance Percent Composition Streblospio benedicti Polychaete 376 38.2 Grandidierella japonica Crustacean 269 27.3 TRE Polydora nuchalis Polychaete 68 6.9 Values were calculated from the total of all sites assessed. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-18 Relative Ranking. The results of the chemistry, toxicity, and benthic community assessments for Tijuana River Estuary were ranked against the same parameters for the other embayments monitored in the ABLM Program (see Section 3.3.5 for a complete discussion). For chemistry, a rank of 1 represents the lowest ERM- Q and 12 represents the highest. For toxicity, a rank of 1 represents the highest percent survival of test organisms and 12 represents the lowest. For benthos, a rank of 1 represents the highest species diversity, abundance and richness and a rank of 12 represents the lowest species diversity, abundance and richness. The results are presented in Figure 12-5. For Tijuana River Estuary, the relative ranks were seven for chemistry, two for toxicity, and six for benthic community structure. These results suggest that the Estuary is lightly impacted by the upstream watershed relative to the other embayments assessed. This is a somewhat unexpected result because historically wet weather water quality in the Tijuana River has been among the worst of any of the watersheds in San Diego County (MEC 2003). The lack of high concentrations of metals and low toxicity associated with the Estuary sediments indicate that the heavy COC loading observed during storm events in the Tijuana River does not lead to a persistent accumulation of COC downstream. Future monitoring will help determine the strength of this relationship. 12.4.1.3 Summary and Conclusions Sediments in Tijuana River Estuary were monitored as part of the 2004 ABLM Program to assess the potential for adverse effects from the watershed and to compare sediment quality with other coastal embayments in San Diego County. In Phase I, a stratified random approach was used to identify the three sites where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size). In Tijuana River Estuary, one site was located in the outer stratum, 1L-2, one in the middle stratum 2L-1, and one was located in the inner stratum 3M-1. These sites were sampled in Phase II of the assessment and analyzed for sediment chemistry, toxicity, and benthic community structure. The results of the chemistry assessment indicated that seven metals common to all embayments were also found in Tijuana River Estuary sediments. Concentrations were low and none exceeded their respective ERLs. In addition, there were no PAHs, PCBs, or pesticides found in the Estuary above the detection limit. As a result, the mean ERM-Q for Tijuana River Estuary was intermediate compared to the other embayments assessed in the ABLM Program. In addition, percent survival of test organisms exposed to Tijuana River Estuary sediments was not significantly different from that of the Control, suggesting that the sediments were not significantly toxic to the test organisms. Benthic community indices suggested that the biotic community in Tijuana River Estuary was intermediate compared to the other embayments assessed. The infaunal community was dominated by a common polychaete worm and a gammarid amphipod. The relative ranks for Tijuana River Estuary were seven for chemistry, two for toxicity, and six for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Tijuana River Estuary had an overall rank of four. During the 2003 ABLM program the Lagoon had an overall rank of one. An increase in overall ranking indicates a decrease in relative quality compared with last year’s ranking. More data will need to be collected before any definitive trends can be identified. 0 1 2 3 4 5 6 7 8 Chemistry Toxicity Benthos RankingFigure 12-5. Relative rankings for sediment in Tijuana River Estuary. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-19 12.5 WMA Assessment The Tijuana River Watershed Management Area was assessed utilizing chemistry and toxicity data collected during storm events from a single MLS, chemistry data collected from three dry weather monitoring sites upstream of the MLS, and IBI scores generated at three bioassessment sites. The watershed management area assessment methods presented in Section 3.4 were applied to these data to determine which constituents were of concern and to develop a high, medium, or low frequency of occurrence for these constituents. The results of this assessment are presented in Table 12-10. Six constituents were determined to have a high frequency of occurrence and are listed below as COC. All of these constituents received a rating of three diamonds based on Criteria No. 1. These include: • Total Coliform • Fecal Coliform • Enterococcus • Total suspended solids • Turbidity • Diazinon Four constituents were found to have a medium frequency of occurrence (two diamonds) based on Criteria No. 6. These constituents include: • BOD • COD • Un-Ionized Ammonia • Total Phosphorus Five constituents were found to have a low frequency of occurrence (one diamond) based on Criteria No. 9. These include: • Dissolved Phosphorus • Surfactants (MBAS) • Total Copper • Chlorpyrifos • Malathion BOD and COD are unique among the COC assessed in the storm water program because they provide an indirect measure of the total oxidizable material available in the water column due to other factors, including anthropogenic contaminants as well as natural processes (as opposed to other methods which only provide results for the specific analyte tested). The presence of BOD or COD above their respective water quality criteria indicates the presence of other contaminants that may have caused the exceedance. Thus, management actions aimed at reducing BOD or COD may be most effective if the source or sources of the elevated levels are addressed directly. In this way, a reduction in BOD or COD levels would be a by-product of actions taken against more easily rectified COC. Potential contaminants of concern are other synthetic organics, trace elements and trash as indicated by the SWRCB 303(d) list for the Tijuana River. The SWRCB 303(d) list also specifies lead, nickel and thallium as COC for the Tijuana River Estuary, downstream of the MLS. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-20 Table 12-10. Constituent exceedances in the Tijuana River WMA. MLS (Wet Weather) Results Dry Weather Results * 2001/2002 2002/2003 2003/2004 2004/2005 CUMULATIVE 2004 Constituents With Any Wet Weather (MLS) WQO or Dry Weather Action Level Exceedance #/3 % #/3 % #/3 % #/3 % #/12 % # % Frequency of Occurrence Criterion No. Conventional Parameters pH 0 0 1 33 0 0 0 0 1 8 0 0 - - BOD 2 67 1 33 3 100 1 33 7 58 NA NA ♦♦ 6 COD 2 67 2 67 3 100 1 33 8 67 NA NA ♦♦ 6 Surfactants (MBAS) 2 67 1 33 1 33 1 33 5 42 0 0 ♦ 9 Total Suspended Solids 2 67 2 67 3 100 3 100 10 83 NA NA ♦♦♦ 1 Turbidity 2 67 3 100 3 100 3 100 11 92 2 50 ♦♦♦ 1 Nutrients Un-ionized Ammonia as N NA NA 3 100 2 67 2 67 7 58 NA NA ♦♦ 6 Dissolved Phosphorus 3 100 0 0 1 33 0 0 4 33 NA NA ♦ 9 Total Phosphorus 3 100 3 100 2 67 1 33 9 75 NA NA ♦♦ 6 Bacteriological Total Coliform 3 100 3 100 3 100 3 100 12 100 0 0 ♦♦♦ 1 Fecal Coliform 3 100 3 100 3 100 3 100 12 100 0 0 ♦♦♦ 1 Enterococcus 3 100 3 100 3 100 3 100 12 100 0 0 ♦♦♦ 1 Pesticides Chlorpyrifos 3 100 1 33 1 33 0 0 5 42 0 0 ♦ 9 Diazinon 3 100 3 100 3 100 2 67 11 92 0 0 ♦♦♦ 1 Malathion NA NA 2 67 2 67 1 33 5 42 NA NA ♦ 9 Total Metals Arsenic 0 0 0 0 1 33 0 0 1 8 NA NA - - Copper 0 0 1 33 2 67 0 0 3 25 NA NA ♦ 9 Lead 0 0 0 0 0 0 2 67 2 17 NA NA - - Nickel 0 0 0 0 1 33 0 0 1 8 NA NA - - Zinc 0 0 0 0 1 33 1 33 2 17 NA NA - - Dissolved Metals Copper 0 0 1 33 0 0 0 0 1 8 0 0 - - Toxicity EVIDENCE OF PERSISTENT TOXICITY? Ceriodaphnia 96-hour 3 100 3 100 3 100 3 100 12 100 NA NA Yes Ceriodaphnia 7-day survival 3 100 3 100 3 100 3 100 12 100 NA NA Yes Ceriodaphnia 7-day reproduction 3 100 3 100 3 100 3 100 12 100 NA NA Yes Hyalella 96-hour 0 0 1 33 2 67 0 0 3 25 NA NA No Bioassessment IBI Rating EVIDENCE OF BENTHIC ALTERATION? Campo Creek NA NA Poor Very Poor Very Poor NA Tijuana River, at Dairy Mart Rd. NA Very Poor NA Poor Very Poor NA Yes * = Total number of observations varied among constituents. NA = Not assessed - = Constituent results are below the defined requirements for a Low Frequency of Occurrence rating. ♦ = Low Frequency of Occurrence rating. ♦♦ = Medium Frequency of Occurrence rating. ♦♦♦ = High Frequency of Occurrence rating. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-21 All of the bioassay tests conducted on Ceriodaphnia dubia have shown evidence of persistent toxicity in all three years of monitoring. Although there has been toxicity to Hyalella azteca during some of the storm events, there is no evidence of persistent toxicity to Hyalella throughout the monitoring period. Cumulative IBI scores resulting from bioassessment monitoring on the Tijuana River throughout the monitoring period indicated a rating of very poor at both sites, suggesting evidence of benthic alteration. It should be noted, though, that the bioassessment monitoring site in Campo is spatially segregated from the water quality monitoring stations located much further downstream. The bioassessment site in Campo is not affected by the communities of Tijuana, Mexico. Figure 12-6 summarizes the number of water quality exceedances for six categories of constituents. Categories include conventionals, nutrients, bacteria, pesticides, metals and toxicity. The stacked bars were developed using number of exceedances from values in Table 12-10 for each constituent category. The overall number of water quality objectives exceedances at the Tijuana River MLS has been consistently high and has the highest number of exceedances in comparison to all other MLS sites. A slight decrease in the total number of exceedances was exhibited in 2004-2005, but with very little relative change within the different constituent categories in comparison to the last three monitoring seasons. Tijuana River Watershed 0 5 10 15 20 25 30 35 40 45 50 2001/2002 2002/2003 2003/2004 2004/2005 Storm SeasonNumber of ExceedancesConventional Parameters Nutrients Bacteriological Pesticides Metals Toxicity Figure 12-6. Stacked bar chart of the number of wet weather exceedances of constituent groups in Tijuana River. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-22 Evaluation of scatterplots for the Tijuana River presented in Appendix C indicate a statistically significant decreasing trend for conductivity (R2=0.41), TDS (R2=0.35), dissolved arsenic (R2=0.33), and dissolved nickel (R2=0.79). A statistically significant increasing trend is evident for TSS (R2=0.34) and enterococcus (R2=0.40) which are two of the six high frequency COC. Triad Decision Matrix The triad decision matrix combines the occurrence of COC with the toxicity and bioassessment results to determine possible conclusions about the watershed and provide possible actions for future monitoring or assessment. Table 12-11 summarizes these results and lists possible conclusions and actions. Table 12-11. Decision matrix results for Tijuana River watershed. Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions Persistent exceedances of water quality objectives (High frequency of occurrence) Evidence of persistent toxicity Indications of benthic alteration Connections of water quality degradation and toxicity to benthic condition difficult due to spatial disparity. 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source as a high priority. The water quality degradation and persistent toxicity observed from monitoring at the MLS in the lower Tijuana River may cause benthic alterations. Unfortunately, without bioassessment data downstream of the MLS, this conclusion cannot be confirmed. As mentioned earlier in this section, hydrologic conditions prevented bioassessment monitoring lower in the Tijuana River. Baseline Long-Term Effectiveness Assessment (BLTEA) Rating Comparison for the Tijuana River WMA The water quality priority ratings presented in Table 12-12 are based on the methodology presented in the BLTEA report (WESTON, MOE, & LWA 2005) and are presented in the Methods Section 3.4. Constituent groups and stressor groups are given a ranking from A to D with A being the highest priority rating and D the lowest priority rating. Items ranked with a D indicate that the constituent group or stressor is a low priority or does not have sufficient data to support a higher ranking. The ratings were based on current results presented in this 2004-2005 annual report and data from the following programs: • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Co-permittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303d Listing Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-23 Table 12-12. Baseline Long-Term Effectiveness Assessment (BLTEA) Ratings for the Tijuana River WMA Priority Ratings* Constituent Groups Stressor Groups Watersheds/Sub- watersheds Percentage of Total Area Heavy Metals Organics Oil and Grease Sediments Pesticides Nutrients Gross Pollutants Bacteria/ Pathogens Benthic Alterations Toxicity Tijuana River WMA 100 % D D D B C B B B B C Tijuana Valley HA (911.10) 7% A A D A A A A A A C Potrero HA (911.20) 18% D D D B C B B B B C Barrett Lake HA (911.30) 20% D D D B C B B B B C Monument HA (911.40) 8% D D D B C C C A B C Morena HA (911.50) 5% D D D B C B B B B C Cottonwood HA (911.60) 10% D D D B C C C C B C Cameron HA (911.70) 10% D D D B C B B B B C Campo HA (911.80) 23% D D D B C B B B B C Notes: * = Rating Calculated Based on Area Weighted Averages of Score Value from the sub-watershed areas. ** = Priority Level (Highest-A to Lowest-D) The purpose of the BLTEA ratings is to identify water quality priorities within a watershed based on weighted averages of the sub-watershed ratings. Because it is a weighted average, larger sub-watersheds will have a greater influence in the overall watershed rating. The Tijuana River WMA did not have any high priority (A) ratings for the overall WMA. The highest rated constituents were sediments, nutrients, gross pollutants, bacteria, and benthic alteration which were all given a B rating. The Tijuana Valley sub-watershed which makes up only 7% of the watershed did have several high priority (A) rated constituents which include, heavy metals, organics, sediments, pesticides, nutrients, gross pollutants, bacteria and benthic alteration. Only toxicity and oil and grease were found to have a low priority in this sub-watershed. The only other high priority (A) rating was for bacteria in the Monument sub-watershed due to bacteria being on the 303(d) list in this area. A regional evaluation and description of the BLTEA is presented in the Regional Assessment Section 13. The complete tables used to calculate the ratings are presented in Appendix G. Tijuana River WMA SECTION 12 2004-2005 Urban Runoff Monitoring Report 12-24 12.6 Conclusions and Recommendations The Tijuana River watershed management area is the largest of the San Diego watersheds covering over 1.1 million acres. Mexico governs the majority of the Tijuana River watershed (73%) with the remaining areas belonging to the United States. Undeveloped areas account for 58% of U.S. lands, with another 25% devoted to parks. The River flows through Tijuana, Mexico and runoff contributions come from both Mexico and the United States. For the Tijuana River WMA, TSS, turbidity, all three bacterial indicators, and Diazinon were identified as high frequency of occurrence COC, followed by BOD, COD, ammonia, and total phosphorus which were identified as medium frequency of occurrence COC, and MBAS, dissolved phosphorus, Chlorpyrifos, Malathion, and total copper were identified as low frequency of occurrence COC. The elevated densities of all three bacterial indicators and elevated levels of BOD, COD, and nutrients (un-ionized ammonia as N and total phosphorus) are indicative of wastewater discharges. Pesticides are also persistently found above WQOs in the watershed. Stream bioassessment monitoring rated the Tijuana River site as Poor, but the investigators in this study feel that this rating is much higher than the actual benthic community quality suggests. The two other bioassessment sites are upstream of any influence from the City of Tijuana and surrounding communities and are not representative of the lower reaches of the Tijuana River directly affected by runoff from these communities. Data collected during the Ambient Bay and Lagoon Monitoring program suggest the elevated concentrations of numerous constituents observed in the Tijuana River are not impacting estuarine sediments. The Tijuana Estuary sediments did not contain any PAHs, PCBs or pesticides and results of toxicity tests were similar to those of a control. Overall, the Tijuana River Estuary received a rating of five compared to other embayments within San Diego County. The Tijuana River Estuary experienced a decrease in relative quality compared with the 2003 ABLM ranking. The BLTEA rating priorities agreed with the WMA assessment findings for the Tijuana Valley sub- watershed but since this sub-watershed is only 7% of the entire Tijuana River WMA, it suggests that the high priorities and COCs may be more localized to the area near the MLS. The Tijuana River WMA did not have any high priority (A) ratings for the overall WMA. The highest rated constituents were sediments, nutrients, gross pollutants, bacteria, and benthic alteration which were all given a B rating. The information provided from the triad matrix results used in conjunction with the BLTEA ratings can assist the jurisdictions in making informed decisions in developing their WURMP programs. The two reports also allow for an evaluation of where data gaps exist and where efforts should be targeted. Utilizing the BLTEA rating methods for future data evaluations would also allow for long-term BMP effectiveness assessment. Incorporation of additional useable data from other third party sources such as the San Diego Coastkeeper, other non-profit organizations, and other POTWs would also help to increase the confidence of the BLTEA ratings and overall WMA assessments. The recommendation for this watershed is to continue monitoring to gather long-term trend information and to identify upstream sources of contamination. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-1 13.0 REGIONAL ASSESSMENTS This section presents a regional assessment of the Receiving Waters Monitoring Program results. Whereas the previous sections presented the results on a watershed management area basis, this regional assessment provides for an analysis of inter-relationships across watersheds, and identifies characteristics of certain watersheds that indicate differences or similarities with the other watersheds in the County. This section includes a cross watershed comparison of wet weather data from the mass loading station monitoring, evaluations of storm water modeling and event mean concentrations, dry weather investigations, stream bioassessment, Ambient Bay and Lagoon monitoring, coastal outfall monitoring, and third party data investigations. 13.1 Cross Watershed Comparison Comparisons between watersheds were performed using several different statistical tools. Watersheds were compared by examining key constituents across watersheds and by grouping similar watersheds by constituent or constituent group relationships. Key constituents were defined as having either been rated as a potential concern based on the frequency and magnitude of exceedance of the applicable water quality objective (WQO) and/or being an indicator of water quality within a constituent group (e.g. total phosphorus is an indicator constituent in the nutrient group). In addition to these statistical comparisons presented in this sub-section, comparisons between watersheds of estimated event mean concentrations (EMCs) with measured EMCs at mass loading stations were also performed. The results from the analysis of the MLS samples for each storm event sampled for the 2004-2005 wet season are summarized in Table 13-1. These results provide a regional comparison of constituent concentrations for the 2004-2005 monitoring period. Results are highlighted where concentrations exceeded the applicable WQO. A comparison of the spatial distribution of exceedances for the 2004- 2005 wet season indicates the following by constituent group: • Bacteria – There were consistent regional exceedances of the WQO for fecal coliform in the wet weather samples with the exception of the Peñasquitos Creek MLS. The highest concentrations were observed at the Tijuana River MLS, which can be expected given the reported discharges of untreated sewage to the river. • Total Dissolved Solids (TDS) – TDS concentrations exceeded the WQO at the MLS during all storm events sampled in the San Luis Rey, Carlsbad, San Dieguito, and Peñasquitos WMA. Exceedances were observed in two of three events at the Sweetwater River MLS. In contrast, concentrations of TDS in all wet weather samples were below the WQO in the Mission Bay, San Diego River, and Tijuana River WMAs. Higher TDS concentrations may indicate greater contributions from higher dissolved mineral salts from groundwater/base flow. • Total suspended Solids (TSS) - Comparing TSS concentrations regionally, WQO were consistently exceeded in samples collected from Agua Hedionda Creek, Tecolote Creek, Chollas Creek, and the Tijuana River. TSS concentrations exceeded the WQO during one of three storm events in most of the other watersheds indicating potential sediment issues on a regional basis. The intensity and duration of storm events most likely had an effect on TSS concentrations. Similar results were observed for turbidity concentrations. Table 13-1. Results of wet weather monitoring.WatershedSourceSan Luis Rey 10/27/04San Luis Rey 02/11/05San Luis Rey 02/18/05Agua Hedionda 10/17/04Agua Hedionda 02/11/05Agua Hedionda 02/18/05Escondido Creek 10/17/04Escondido Creek 02/11/05Escondido Creek 02/18/05San Dieguito River 10/17/04San Dieguito River 02/11/05San Dieguito River 02/18/05Penasquitos Creek 10/17/04Penasquitos Creek 02/11/05Penasquitos Creek 02/18/05General/Physical/OrganicElectrical Conductivity umhos/cm927 2790 1865 1760 502 700 2860 2530 1390 3210 3380 1744 3270 2690 1213Oil & Grease mg/L 15 USEPA Multi-Sector General Permit<1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1pH pH scale 6.5-8.5 Basin Plan7.20 No Data 8.06 7.50 No Data 7.76 7.91 8.16 8.10 7.82 7.70 6.84 7.76 7.48 6.85BacteriologicalEnterococci MPN/100mL 80,000 5,000 13,000 280,000 7,000 50,000 8,000 1,700 50,000 140,000 130 1,300 1,112 3,000 8,000Fecal Coliform MPN/100mL 400/4000 Basin Plan REC1/REC250,000 1,700 8,000 30,000 5,000 50,000 1,300 1,100 50,000 14,000230500500 500 2,200Total Coliform MPN/100mL 170,000 11,000 11,000 300,000 17,000 80,000 17,000 13,000 230,000 300,000 800 3,000 17,000 13,000 50,000Wet ChemistryAmmonia as N mg/L<0.1 <0.1 <0.1 0.82 0.23 0.18 0.33 0.26 0.32 <0.1 0.17 0.16 <0.1 0.14 <0.1Un-ionized Ammonia as Nμg/L 25 (a) Basin Plan0.2 0.4 1.4 4.4 0.4 4.1 1.3 6.036.81.2 1.9 3.0 0.9 0.3 0.1Biochemical Oxygen Demand mg/L 30 USEPA Multi-Sector General Permit4.09 2.61 <232.24.67 3.64 6.26 3.32 5.2 21.8 3.33 <2 23.7 3.75 2.31Chemical Oxygen Demand mg/L 120 USEPA Multi-Sector General Permit32 58 4027975 39 68 37 42 <251234114362 36Dissolved Organic Carbon mg/L37.9 5.81 4.27 28.9 7.3 7.2 29 3.86 6.47 35.9 5.42 5.21 27.2 4.44 4.66Dissolved Phosphorus mg/L 2 USEPA Multi-Sector General Permit0.46 0.36 <0.05 1.1 0.44 0.51 0.26 <0.05 <0.05 0.16 0.13 0.12 0.14 0.1 0.51Nitrate as N mg/L 10 Basin Plan0.58 5.99 5.18 1.93 2.41 0.88 2.71 7.2 6.32 0.16 1.67 1.81 0.09 0.6 1.06Nitrite as N mg/L 1 Basin Plan<0.05 <0.05 <0.05 <0.05 <0.05 0.09 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05Methylene Blue Active Substances mg/L 0.5 Basin Plan<0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5Total Dissolved Solids mg/L 500-2100 Basin Plan by watershed652 1280 1100 852 7524161460 1410 965 2100 1630 982 2120 1500 804Total Kjeldahl Nitrogen mg/L2.4 1.7 2 14.1 1.3 3.6 2 0.7 3 1.4 1.6 2 1.6 1.9 0.8Total Organic Carbon mg/L51.3 7.8 10.2 44.7 7.31 14.2 34 6.9 13.8 36.3 9.54 10.9 29.9 9.51 10.8Total Phosphorus mg/L 2 USEPA Multi-Sector General Permit0.58 0.84 0.572.150.47 1.12 0.28 0.26 0.62 0.19 0.14 0.45 0.14 0.28 0.69Total Suspended Solids mg/L 100 USEPA Multi-Sector General Permit16530 78962 246 85960 7226428 24 28 <20 <20108Turbidity NTU 20 Basin Plan13611.931.3 383 27.5 21415.4 13.41176.77 6.01 18.3 7.89 9.0556.4Chlorpyrifosμg/L 0.02 CA Dept. of Fish & Game<0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01Diazinonμg/L 0.08 CA Dept. of Fish & Game<0.01 0.030 <0.010.2670.044 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01Malathionμg/L 0.43 CA Dept. of Fish & Game<0.01 <0.01 <0.01 0.330 0.083 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01HardnessHardness mg CaCO3/L353 650 581 422 387 225 700 663 514 967 767 487 1000 707 379Total MetalsAntimony mg/L 0.006 Basin Plan<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005Arsenic mg/L 0.34/0.05 40 CFR 131/ Basin Plan0.002 0.003 <0.002 0.008 0.007 <0.002 0.003 0.004 <0.002 0.006 0.007 <0.002 0.005 0.004 <0.002Cadmium mg/L (b) 40 CFR 131<0.001 <0.001 <0.001 0.002 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001Chromium mg/L (b) CTR (Cr VI)<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005Copper mg/L (b) 40 CFR 1310.011 0.005 0.005 0.032 0.012 0.018 0.008 0.022 0.02 0.005 <0.005 <0.005 <0.005 <0.005 <0.005Lead mg/L (b) 40 CFR 131<0.002 <0.002 <0.002 0.007 0.004 0.006 <0.002 0.002 0.005 0.002 <0.002 <0.002 <0.002 <0.002 0.002Nickel mg/L (b)/0.1 40 CFR 131/ Basin Plan0.011 0.002 0.002 0.028 0.007 0.007 0.004 0.002 0.003 0.003 0.003 0.002 0.003 0.002 0.002Selenium mg/L 0.02 40 CFR 131<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005Zinc mg/L (b) 40 CFR 131<0.02 <0.02 <0.02 0.270 0.042 0.060 0.020 0.022 0.052 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02Dissolved MetalsAntimony mg/L (e) 40 CFR 131<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005Arsenic mg/L 0.34 ( c) 40 CFR 131<0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002Cadmium mg/L (b) 40 CFR 131<0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001Chromium mg/L (b) 40 CFR 131<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005Copper mg/L (b) 40 CFR 131<0.005 <0.005 <0.005 0.006 0.005 <0.005 <0.005 0.007 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005Lead mg/L (b) 40 CFR 131<0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002Nickel mg/L (b) 40 CFR 131<0.002 0.002 0.002 0.007 0.003 0.002 0.003 0.002 <0.002 0.003 0.003 0.002 0.003 0.002 0.002Selenium mg/L 0.2 (d) 40 CFR 131<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005Zinc mg/L (b) 40 CFR 131<0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02ToxicityCeriodaphnia 96-hr NOEC (%) 100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100 >100Ceriodaphnia 7-day survival NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100Ceriodaphnia 7-day reproduction NOEC (%) 100 100 100 100 100 100 100 100 100 10025100 100 100 100 100Hyalella 96-hr NOEC (%) 100 100 100 10025100 100 100 100 100 100 100 100 100 100 100Selenastrum 96-hr NOEC (%) 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100See last page for footnotes and source references.ANALYTE UNITS WQOPesticidesSan Luis Rey River Carlsbad San Dieguito River Peñasquitos Lagoon Table 13-1. Results of wet weather monitoring.WatershedSourceGeneral/Physical/OrganicElectrical Conductivity umhos/cmOil & Grease mg/L 15 USEPA Multi-Sector General PermitpH pH scale 6.5-8.5 Basin PlanBacteriologicalEnterococci MPN/100mL Fecal Coliform MPN/100mL 400/4000 Basin Plan REC1/REC2Total Coliform MPN/100mL Wet ChemistryAmmonia as N mg/LUn-ionized Ammonia as Nμg/L 25 (a) Basin PlanBiochemical Oxygen Demand mg/L 30 USEPA Multi-Sector General PermitChemical Oxygen Demand mg/L 120 USEPA Multi-Sector General PermitDissolved Organic Carbon mg/LDissolved Phosphorus mg/L 2 USEPA Multi-Sector General PermitNitrate as N mg/L 10 Basin PlanNitrite as N mg/L 1 Basin PlanMethylene Blue Active Substances mg/L 0.5 Basin PlanTotal Dissolved Solids mg/L 500-2100 Basin Plan by watershedTotal Kjeldahl Nitrogen mg/LTotal Organic Carbon mg/LTotal Phosphorus mg/L 2 USEPA Multi-Sector General PermitTotal Suspended Solids mg/L 100 USEPA Multi-Sector General PermitTurbidity NTU 20 Basin PlanChlorpyrifosμg/L 0.02 CA Dept. of Fish & GameDiazinonμg/L 0.08 CA Dept. of Fish & GameMalathionμg/L 0.43 CA Dept. of Fish & GameHardnessHardness mg CaCO3/LTotal MetalsAntimony mg/L 0.006 Basin PlanArsenic mg/L 0.34/0.05 40 CFR 131/ Basin PlanCadmium mg/L (b) 40 CFR 131Chromium mg/L (b) CTR (Cr VI)Copper mg/L (b) 40 CFR 131Lead mg/L (b) 40 CFR 131Nickel mg/L (b)/0.1 40 CFR 131/ Basin PlanSelenium mg/L 0.02 40 CFR 131Zinc mg/L (b) 40 CFR 131Dissolved MetalsAntimony mg/L (e) 40 CFR 131Arsenic mg/L 0.34 ( c) 40 CFR 131Cadmium mg/L (b) 40 CFR 131Chromium mg/L (b) 40 CFR 131Copper mg/L (b) 40 CFR 131Lead mg/L (b) 40 CFR 131Nickel mg/L (b) 40 CFR 131Selenium mg/L 0.2 (d) 40 CFR 131Zinc mg/L (b) 40 CFR 131ToxicityCeriodaphnia 96-hr NOEC (%) 100Ceriodaphnia 7-day survival NOEC (%) 100Ceriodaphnia 7-day reproduction NOEC (%) 100Hyalella 96-hr NOEC (%) 100Selenastrum 96-hr NOEC (%) 100See last page for footnotes and source references.ANALYTE UNITS WQOPesticidesTecolote Creek 10/27/04Tecolote Creek 02/11/05Tecolote Creek 02/18/05San Diego River 10/27/04San Diego River 02/11/05San Diego River 02/18/05Chollas Creek 10/17/04Chollas Creek 02/11/05Chollas Creek 02/18/05Sweetwater River 10/17/04Sweetwater River 02/11/05Sweetwater River 02/18/05Tijuana River 10/27/04Tijuana River 02/11/05Tijuana River 02/18/05167 473 199 560 126 747 565 348 159 529 5070 3260 430 1449 1075<1 1.32 <1 <1 <1 <1 4.17 1.12 <1 <1 <1 <1 2 4.69 5.286.78 6.90 7.14 7.16 7.63 7.20 7.09 7.61 7.81 7.24 7.52 7.49 7.75 7.65 7.43300,000 50,000 30,000 22,000 2,300 22,000 170,000 30,000 80,000 800 3,000 50,000 800,000 3,000,000 1,700,00070,000 13,000 17,000 5,000 800 1,300 140,000 11,000 70,0003001,300 1,300 5,000,000 2,400,000 2,200,000800,000 130,000 130,000 300,000 30,000 50,000 3,000,000 130,000 170,000 30,000 13,000 28,000 5,000,000 5,000,000 9,000,0000.39 0.35 <0.1 0.38 0.28 0.95 2.13 0.28 0.19 0.39 0.14 0.14 4.5 8.14 3.280.6 0.1 0.5 0.2 0.5 8.2 2.4 5.946.71.0 0.8 1.1 24.186.1 42.77.45 7.75 3.65 4.22 3.68 3.39 138 4.83 3.79 19.8 2.57 3.42 23.96726.617388 25 982835650189 <25 4412374 761975034 7.8 4.44 33.2 2.94 5.62 134 2.22 2.86 25.7 5.24 6.19 39.2 20.3 8.650.89 0.46 <0.05 0.44 <0.05 0.32 1.68 0.2 <0.05 0.2 0.18 0.45 1.69 1.73 1.260.53 0.5 0.42 0.37 0.66 1.01 4.38 0.62 0.61 0.07 1.02 1.93 4.08 1.97 2.12<0.05 <0.05 <0.05 <0.05 <0.05 <0.05 0.15 0.05 0.05 <0.05 <0.05 <0.05 0.11 0.37 <0.05<0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.50.70.5174 627 285 594 756 490 665 122 1122860 23701410 400 938 6646 1 6.2 2.3 <0.5 23.3 18.6 5.4 3.4 2.1 1.4 1.8 19.4 18.2 10.436.4 12.1 8.27 62 9.61 9.6 190 7.58 10.7 30.1 10.9 11.7 55.5 25.7 23.52.870.47 0.5 0.85 0.28 0.44 1.85 0.3 0.45 0.25 0.57 0.47 1.732.71.742180 229 245 47750 61753 135 27520 26102 7440 890 2900540 44.7 67.4 23414.530.9 300 40.1 82.24.03 5.8 48.84540 60.2 537<0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01<0.01 0.051 <0.01 <0.01 0.038 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.010.394 0.169<0.01 0.063 <0.01 <0.01 <0.01 <0.010.6010.091 0.065 <0.01 <0.01 <0.01 <0.010.498<0.01126 330 152 201 364 251 244 40 46 1210 991 556 702 376 350<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.0050.006 0.009 <0.002 0.006 0.006 <0.002 0.007 0.004 <0.002 0.004 0.005 <0.002 0.013 0.01 0.0030.001 <0.001 <0.001 <0.001 <0.001 <0.001 0.003 <0.001 <0.001 <0.001 <0.001 <0.001 0.001 <0.001 <0.001<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 0.014 0.0060.0380.018 0.010 0.025 0.006 0.0060.122 0.009 0.015<0.005 <0.005 0.005 0.017 0.038 0.0430.065 0.019 0.011 0.060 0.005 0.004 0.079 0.008 0.018 <0.002 <0.002 0.002 0.0090.057 0.0560.012 0.005 0.003 0.006 0.003 0.002 0.040 0.003 0.003 0.002 0.003 0.002 0.051 0.015 0.019<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.0050.2370.086 0.065 0.213 0.033 0.0321.180.0540.100<0.02 <0.02 <0.02 0.1650.3920.337<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002<0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.005 0.006 <0.005 <0.005 <0.005 0.005 0.024 0.006 <0.005 <0.005 <0.005 <0.005 0.005 <0.005 <0.005<0.002 0.003 <0.002 <0.002 <0.002 <0.002 0.004 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 0.003 <0.002<0.002 0.003 <0.002 0.003 0.002 0.002 0.027 <0.002 <0.002 0.002 0.003 0.002 0.006 0.009 0.006<0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005<0.02 <0.02 <0.02 <0.02 <0.02 <0.020.2670.023 <0.02 <0.02 <0.02 <0.02 <0.02 0.023 <0.02>100 >100 >100 >100 >100 >100 >100 >100 >10050>100 >10050 25 25100 100 100 100 100 100 100 100 10025100 10025 25 25100 100 100 100 100 10025100 10012.5 5010050 25 25100 100 100 100 100 10050100 100 100 100 100 100 100 100100 100 100 100 100 100 100 100 10050100 100 100 100 100Mission Bay San Diego River San Diego Bay Tijuana River Table 13-1. Results of wet weather monitoring.SourcesSiepmann and Finlayson 2000.Basin Plan, September 8, 1994.Assembly Bill 411 - Title 17 of the California Code of Regulations, Section 7958.USEPA Federal Register Document 40 CFR Part 131, May 18, 2000.(e) USEPA has not published an aquatic life criterion value.Shaded text – exceeds water quality objective.* Indicates detection limit exceeds water quality objective.USEPA National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities, 65 Federal Register (FR) 64746, Final Reissuance, October 30, 2000. Table 3 - Parameter benchmark values.(a) Un-ionized Ammonia is a calculated value, non-detectable values calculated at the detection limit. Basin Plan WQO is 0.025 mg/L; values shown here have been converted to μg/L.(c) Water Quality Objectives for dissolved metal fractions are based on water effects ratios (WER) and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(b) Water Quality Objective for dissolved metal fractions are based on total hardness and are calculated as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000.(d) Water Quality Objective is based on the total recoverable form as described by the USEPA Federal Register Doc. 40 CFR Part 131, May 18, 2000. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-5 • Nutrients – Total phosphorus, Nitrate, and Nitrite – Total phosphorus concentrations exceeded WQO during one of the three wet weather events at Agua Hedionda Creek, Tecolote Creek, and the Tijuana River. Nitrite concentrations exceeded the WQO during one storm event at the Tijuana River MLS. No exceedances were reported for nitrate. On a regional basis, nutrient concentrations appear to have been generally below WQO with exceptions as noted. • Total Metals – Copper and Zinc – Copper concentrations exceeded the WQO during two storm events in Chollas Creek and one event in Tecolote Creek. Similar observations were reported for zinc concentrations, with an exceedance also reported for one storm event in the Tijuana River. For the 2004-2005 wet season, water quality issues regarding total metals were limited to these MLS. • Toxicity – WQO exceedances based on the toxicity testing indicated that toxicity was generally not a water quality issue regionally, but was a consistent issue at the Tijuana River MLS. Toxicity issues were also indicated for the first sampling event in October 2004 in Chollas Creek and Sweetwater River, and appeared to be indicative of a first flush phenomenon at these MLS. The results for the 2004-2005 monitoring period as presented in Table 13-1 are combined with the previous years results in the following sub-sections, and were statistically compared to further identify spatial and temporal differences, commonalities, and trends between watersheds. 13.1.1 Statistical Analyses Statistical analyses for cross watershed comparisons included magnitude of WQO exceedance and regression (trend) analysis, analysis of variance (ANOVA), multivariate cluster analysis, and multiple regression (relationships between toxicity and COC) (See Section 3.6 for a complete discussion on cross watershed comparisons). The cross watershed comparison of the magnitude of WQO exceedance for key constituents was based on the ratio of the annual mean concentration for the past four years of data to the appropriate WQO. These comparisons provide for identification of water quality issues specific to a watershed or common among several or all watersheds in the region. Scatterplots for each constituent for the years monitored were discussed and presented in the individual watershed sections. A cross- watershed comparison of constituents that indicate significant trends to date is presented in this section. The ANOVA was used to determine statistical differences between the watersheds for the current reporting year as a whole (storms were used for replication). The cluster analysis was used to identify mass loading stations and sampling dates with similar COC loadings. Multiple regression compared toxicity results to COC concentrations. 13.1.1.1 Magnitude of WQO Exceedance and Trend Analysis Results The purpose of this cross-watershed comparison is to identify constituents that are of concern regionally, or specific to a single or multiple watersheds based on the magnitude of exceedance of the WQO. In addition to this spatial analysis, this comparison also identifies temporal characteristics on a regional basis using the last four years of wet weather data. The magnitude of exceedance is based on the ratio of the annual mean concentration from the wet weather data to the applicable water quality objective. A value of greater than one represents an exceedance of the WQO. The figures presented in this sub-section identify this exceedance by a dark line through the value of one for the mean ratio to WQO. Each of the last four years of monitored data is represented as a single bar with the specific monitoring period identified in the legend. Comparisons are presented from each of the constituent groups including Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-6 conventionals, nutrients, pesticides, metals, toxicity, and bacteriological indicators. Trend analysis results are also presented where significant trends based on regression analysis were identified for more than one watershed to allow for a regional comparison. The trend analysis discussion follows the presentation of the exceedance ratio for each constituent group. Conventionals Figure 13-1 presents the regional comparison of the magnitude of exceedance of the WQO for total suspended solids (TSS) and total dissolved solids (TDS) for each of the MLS monitored during the wet season over the last four years. As indicated on Figure 13-1, the greatest WQO exceedances for TSS occurred in Agua Hedionda Creek, Tecolote Creek, and the Tijuana River. The greatest exceedance was for the Tijuana River MLS. The ratio of annual mean concentration of TSS to the WQO for the 2003- 2004 monitoring period for Santa Margarita River WMA was also one of the greatest exceedances, but was not consistent with the other years. There was no data for the 2004-2005 monitoring year. Across watersheds, the highest TSS exceedances were observed for the 2004-2005 period which corresponds to one of the wettest years on record. Large and high intensity storm events mobilize a greater amount of sediment which then correlates to higher TSS concentrations. The lowest TSS concentrations and ratios consistently below one were observed for the San Luis Rey River, San Dieguito River, Peñasquitos Creek, and Sweetwater River. On a regional basis, TSS annual mean concentrations have exceeded the WQO in 7 of the 11 MLS over the last 4 years indicating that TSS, which is an indicator of sediment loading, is a regional water quality issue. Higher TSS levels may be associated with an increase in land disturbance activities in the watershed and increased impervious areas upstream of creek and river sections that may be subject to bank erosion from greater and more sustained peak flows. Temporal patterns in TSS concentrations indicate higher concentrations during greater intensity storm events. Figure 13-1 also provides a cross-watershed comparison for the exceedance of the WQO for TDS. The monitored MLS that indicate the greatest WQO exceedance based on the annual means for the last four years of wet weather data include the San Luis Rey River, Escondido Creek, the San Dieguito River, and Peñasquitos Creek. These generally correspond to the watersheds that had the lowest ratios for TSS. Higher TDS concentrations may be correlated to greater concentrations of dissolved minerals and metal salts from groundwater contributions to the base flow and local geological characteristics. The temporal patterns for TDS concentrations did not show significant variation as compared to TSS concentrations, which are influenced more by intensity and duration of storm events. However, higher TDS concentrations were generally observed during the drier years when a greater contribution of base flow would be anticipated as part of the total storm water flow. Trend analyses of the conventional constituents indicated statistically significant increasing trends across watersheds. As shown on Figure 13-2, significant trends were identified for TSS in Agua Hedionda Creek and the Tijuana River. These trend lines are based on regression analysis of wet-weather data. TSS concentrations in both of these watersheds have been consistently above the water quality objective. These increasing trends are also indicated on Figure 13-1 which shows the increasing magnitude of exceedance. This increasing trend may also be associated with greater intensity and frequency of storm events which may correlate to higher TSS concentrations. Increasing trends were also observed for turbidity in Agua Hedionda Creek and Chollas Creek as shown on Figure 13-2. The increase in turbidity for Aqua Hedionda Creek correlates to the TSS increasing trend. Increasing concentrations of TSS and turbidity in Agua Hedionda Creek may be reflective of increased land disturbance activities and a potential increase in stream bank erosion due to longer and greater peak flows that result from increased impervious areas. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-7 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua HediondaCreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQOTotal Suspended Solids No Data17 937 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua HediondaCreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQOTotal Dissolved Solids No Data Figure 13-1. Regional Comparison of Mean Annual Concentration to WQO Ratio – Conventionals – Total Suspended Solids and Total Dissolved Solids. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-8 Significant decreasing trends were indicated for conductivity in Agua Hedionda Creek, the San Diego River, and the Tijuana River as shown on Figure 13-2. These decreasing trends may correspond to the lower and generally decreasing magnitude of exceedance of TDS for these watersheds as shown on Figure 13-1. All other reported trends for conventional constituents were for only one watershed or none for the other constituents in this group, and are therefore not presented in this regional discussion. 94 96 98 00 02 04 0 2,000 4,000 6,000 Conductivity (μmhos/cm)94 96 98 00 02 04 0 2,000 4,000 6,000 94 96 98 00 02 04 0 2,000 4,000 6,000Agua Hedionda Creek San DiegoRiver Tijuana River 94 96 98 00 02 04 0 200 400 600 Turbidity (NTU)Agua Hedionda Creek 94 96 98 00 02 04 0 200 400 600 Chollas Creek 94 96 98 00 02 04 0 1,000 2,000 3,000 4,000 Total Suspended Solids (mg/L)Agua Hedionda Creek 94 96 98 00 02 04 0 1,000 2,000 3,0004,000 8,000 Tijuana River Significant Trend Water Quality Objective R2 = 0.31 R 2 = 0.67 R 2 = 0.41 R2 = 0.27 R 2 = 0.12 R2 = 0.44 R2 = 0.34 Figure 13-2. Regional Comparison of Significant Trends – Conventionals – Total Suspended Solids, Turbidity and Conductivity. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-9 Nutrients Figure 13-3 presents the regional comparison of the ratio of the annual mean concentration of ammonia and total phosphorus to the WQO. For both of these constituents, the only MLS that exceeded the WQO was the Tijuana River. Regionally, the concentrations of these constituents were below the WQO and did not vary significantly across watersheds. With the exception of the Tijuana River that has reported discharges of untreated sewage, nutrients do not appear to be a regional water quality issue. Evidence of untreated sewage at the Tijuana River MLS is further observed in WQO exceedances for BOD and nitrate at this location. Long-term increasing trends that may become water quality issues for specific watersheds are discussed below. Significant trends for nutrients are presented on Figure 13-4. Statistically significant increasing trends were observed for nitrate at the San Luis Rey River and the San Dieguito River. Increasing trends were also identified for total phosphorus concentrations in Agua Hedionda Creek, the San Dieguito River, and Tecolote Creek as shown on Figure 13-4. Although increasing trends for nitrate were observed in the San Luis Rey River and San Dieguito River and an increasing trend for total phosphorus were indicated for the San Dieguito River, the concentrations are well below the WQO as shown on Figure 13-3. These temporal patterns for these constituents should continue to be monitored to confirm these trends and assure that WQO are not exceeded. Pesticides Figure 13-5 presents the magnitude of exceedance of the WQO on a cross-watershed basis for the pesticides Diazinon and Chlorpyrifos based on the wet weather results. The annual mean concentration of Diazinon exceeded the WQO in the majority of the watersheds during the 2001-2002 and 2002-2003 monitoring periods. Concentrations of Diazinon exceeded WQO at only three MLS in the last two years of monitoring, including Agua Hedionda Creek, Chollas Creek, and the Tijuana River. The highest exceedances were observed for Escondido Creek, Chollas Creek, and the Tijuana River. With the exception of Agua Hedionda Creek and the Tijuana River, Diazinon concentrations have decreased well below the WQO regionally in the last year. These regional trends are further confirmed in the trend analysis shown in Figure 13-6 for Diazinon. The trend lines are based on regression analysis of the wet- weather data. Significant decreasing trends are indicated for five MLS, including Escondido Creek, Peñasquitos Creek, Tecolote Creek, the San Diego River, and Sweetwater River. These trend analyses and comparisons to WQO indicate a significant decrease in Diazinon concentrations in wet weather samples for most watersheds. No significant trends were indicated for Chlorpyrifos. Since the EPA has banned the retail sale of Diazinon and Chlorpyrifos, and with the increased public outreach and education regarding the handling of pesticides in general, a decreasing trend for these compounds should continue. Continued monitoring for the organophosphate compounds should show a decrease in the concentrations of these compounds with the expectation that residual public supply and use will eventually be exhausted. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-10 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua Hedionda CreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQOAmmonia No Data10 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua Hedionda CreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQOTotal Phosphorus No Data Figure 13-3. Regional Comparison of Mean Annual Concentration to WQO Ratio – Nutrients – Ammonia and Total Phosphorus. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-11 94 96 98 00 02 04 0 1 2 3 4 5 Total Phosphorus (mg/L)Agua Hedionda Creek 94 96 98 00 02 04 0 1 2 3 4 5 San Dieguito River 94 96 98 00 02 04 0 1 2 3 4 5 Tecolote Creek 94 96 98 00 02 04 0 4 8 12 Nitrate as N (mg/L)San Luis ReyRiver 94 96 98 00 02 04 0 4 8 12 San DieguitoRiver Significant Trend Water Quality Objective R2 = 0.30 R 2 = 0.43 R 2 = 0.13 R2 = 0.39 R 2 = 0.37 Figure 13-4. Regional Comparison of Significant Trends – Nutrients – Nitrate and Total Phosphorus. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-12 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua Hedionda CreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQODiazinon No Data9 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua Hedionda CreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQOChlorpyrifos No Data Figure 13-5. Regional Comparison of Mean Annual Concentration to WQO Ratio – Pesticides – Diazinon and Chlorpyrifos. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-13 94 96 98 00 02 04 0 0.2 0.4 0.6 0.8 1 Diazinon (μg/L)Escondido Creek 94 96 98 00 02 04 0 0.2 0.4 0.6 0.8 1 Penasquitos Creek 94 96 98 00 02 04 0 0.2 0.4 0.6 0.8 1 Tecolote Creek 94 96 98 00 02 04 0 0.2 0.4 0.6 0.8 1 Diazinon (μg/L)San Diego River 94 96 98 00 02 04 0 0.2 0.4 0.6 0.8 1 Sweetwater River Significant Trend Water Quality Objective R2 = 0.47 R 2 = 0.45 R 2 = 0.30 R2 = 0.58 R 2 = 0.34 Figure 13-6. Regional Comparison of Significant Trends – Pesticides – Diazinon. Metals Comparison of exceedance ratios based on the annual mean concentrations from the wet-weather data for total copper and zinc are presented for all the watersheds on Figure 13-7. The greatest magnitude of exceedance of the WQO for both copper and zinc occurred at Chollas Creek for all four years of wet- weather data. Exceedances of the WQO were also observed during one year at the Tijuana River MLS for both copper and zinc. The concentrations of these two metals have not exceeded the WQO (ratios less than one) in the other watersheds over the last four years (exception is the annual mean for 2002- 2003 for total copper in the Santa Margarita River WMA). The highest mean concentrations of both copper and zinc at the MLS in Chollas Creek and the Tijuana River were observed for the 2003-2004 monitoring period. Although below the WQO, the next three highest ratios were observed for Tecolote Creek, Agua Hedionda Creek, and the San Diego River. Regionally, these metals are not a consistent wet-weather water quality issue, except as indicated at the Chollas Creek and Tijuana River MLS. Trend analysis based on regression analysis of the wet-weather data indicate no significant trends for total metals in more than one watershed with the exception of total lead. A decreasing trend in total lead concentrations was noted for Tecolote Creek and Chollas Creek as shown on Figure 13-8. An increasing trend has been observed for Agua Hedionda Creek, however concentrations were below WQO. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-14 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua Hedionda CreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQOTotal Copper No Data 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua Hedionda CreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQOTotal Zinc No Data Figure 13-7. Regional Comparison of Mean Annual Concentration to WQO Ratio – Metals – Copper and Zinc. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-15 94 96 98 00 02 04 0 0.05 0.1 0.15 0.2 Total Lead (mg/L)Agua Hedionda Creek 94 96 98 00 02 04 0 0.05 0.1 0.15 0.2 Tecolote Creek 94 96 98 00 02 04 0 0.05 0.1 0.15 0.2 Chollas Creek Significant Trend Water Quality Objective R2 = 0.26 R2 = 0.17 R 2 = 0.14 Figure 13-8. Regional Comparison of Significant Trends – Metals – Total Lead. Toxicity Figure 13-9 presents the regional comparison of the magnitude of exceedance of the WQO for toxicity based on the wet-weather data collected at the MLS. The greatest exceedances for Ceriodaphnia survival occurred at the Tijuana River MLS. Exceedance ratios above one were also observed for Chollas Creek, Escondido Creek, Agua Hedionda Creek, and Sweetwater River. Only the Tijuana River MLS results indicate consistent exceedances of the WQO and magnitudes of exceedance well above one. Similar results were observed on a regional basis for Ceriodaphnia reproduction, with the greatest exceedances occurring at the Tijuana River. Exceedance ratios above one were also observed at Chollas Creek, Escondido Creek, Sweetwater River, the Santa Margarita River, and the San Dieguito River. Based on the last two years of wet-weather data, toxicity does not appear to be a regional water quality issue with the exception of the Tijuana River, Chollas Creek, and Sweetwater River. Toxicity issues at the Tijuana River and Chollas Creek may be associated with the metal and pesticide exceedances discussed above. Due to the numerous water quality issues in the Tijuana River as identified in this discussion, there are likely compound factors impacting toxicity results at this MLS. Further statistical analysis of toxicity results are presented in this subsection. Bacteria Figure 13-10 presents the cross-watershed comparison of the ratio of the mean annual concentrations to the WQO for fecal coliform based on the wet-weather data. Regionally, the concentration of fecal coliform has exceeded the WQO in all watersheds in multiple years. The highest exceedances occurred in the Tijuana River, which has multiple water quality issues most likely associated with the reported discharges of untreated sewage. Indicator bacteria appear to be a consistent regional water quality issue. Results of regression analysis of wet-weather data for bacteriological indicators are presented on Figure 13-11. Significant increasing trends are indicated for enterococci for Tecolote Creek, the San Luis Rey River, and the Tijuana River, and for fecal coliform in the San Luis Rey River and Agua Hedionda Creek. The fecal coliform concentrations in the San Luis Rey River have increased from below WQO to above the WQO during the past monitoring year. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-16 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua Hedionda CreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQOCeriodaphnia Survival - 7 day (TU - 0.9)No Data10 12 0 1 2 3 4 5 6 7 8 Santa Margarita RiverSan Luis Rey RiverAgua Hedionda CreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana RiverMean Ratio to WQO2001/02 2002/03 2003/04 2004/05 Above WQOCeriodaphnia Reproduction - 7 day (TU - 0.9)No Data1012 10 Figure 13-9. Regional Comparison of Mean Annual Concentration to WQO Ratio – Toxicity – Ceriodaphnia Survival and Reproduction. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-17 Santa Margarita RiverSan Luis Rey RiverAgua Hedionda CreekEscondido CreekSan Dieguito RiverPenasquitos CreekTecolote CreekSan Diego RiverChollas CreekSweetwater RiverTijuana River0 20 40 60 80 100 120 60012001800 Ratio to WQO2001/02 2002/03 2003/04 2004/05 Fecal Coliform Above WQONo data Figure 13-10. Regional Comparison of Mean Annual Concentration to WQO Ratio – Bacteria – Fecal Coliform. 94 96 98 00 02 04 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Enterococci (MPN/100ml)San Luis ReyRiver 94 96 98 00 02 04 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Tecolote Creek 94 96 98 00 02 04 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Tijuana River 94 96 98 00 02 04 10 100 1,000 10,000 100,000 1,000,000 10,000,000 100,000,000 Fecal Coliform (MPN/100ml)San Luis ReyRiver 94 96 98 00 02 04 1 10 100 1,000 10,000 100,000 1,000,000 10,000,000 100,000,000 Agua HediondaCreek Significant Trend Water Quality Objective R2 = 0.34 R2 = 0.46 R2 = 0.40 R2 = 0.52 R2 = 0.29 Figure 13-11. Regional Comparison of Significant Trends – Bacteria – Enterococcus and Fecal Coliform. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-18 13.1.1.2 ANOVA Results ANOVA was used to further examine differences between the results (mean concentrations) at each MLS for key constituents based on the 2004-2005 wet weather data. The term analysis of variance is sometimes a source of confusion. In spite of its name, ANOVA is concerned with differences between means of groups, not differences between variances. The analysis uses variances to detect whether the means are different. The ANOVA determines the variation (variance) within the groups that are being compared (e.g., monitoring stations), then compares that variation to the differences between the groups, taking into account how many subjects there are in the groups. If the observed differences between the means of groups are larger than those expected by chance relative to the underlying variance, statistical significance is achieved. For this report, each of the key constituents that were observed in any sample above the method detection limit (MDL) was tested by ANOVA. Because this statistical analysis needs to calculate a variance for each group to be compared, the COC with results below the detection limit at a station were handled as suggested in USEPA (1998). If only one sample was below the detection limit, one-half the detection limit was used; if more than one sample was below the detection limit, each of the values was set so that the mean of all the values would be one-half the detection limit. For example, if the detection limit was 0.6 and there were two values below the detection limit, one would be set to 0.15 and the other would be set to 0.45 so that the mean of the two values was 0.3 (one-half the detection limit). The bacteriological measures were log10 transformed for this analysis. The results of the ANOVA with comparisons of the mean values for significant test results performed on the 2004-2005 monitoring data are presented in Figure 13-12. The probability value of the ANOVA for each of the toxicity test endpoints and constituent are shown next to the corresponding test. The mean station values are shown in ascending order for the toxicity endpoints and in descending order for the key constituents. The colored lines under the means designate those stations that were not significantly different from each other. Conversely, two stations without a common line were significantly different from each other. The ANOVA results indicate that there were statistically significant differences (p < 0.05) between mean station toxicity endpoints for Ceriodaphnia acute and chronic survival for the MLS in the Tijuana River compared to all the other stations. This indicates a significant difference in toxicity at the Tijuana River MLS. As discussed above in the cross-watershed comparison of magnitude of WQO exceedances, the Tijuana River has consistent water quality issues for numerous constituents that may result in toxicity effects. The presence of untreated sewage in the Tijuana River results in significant differences for this MLS not only for toxicity, but also for fecal coliform, ammonia, oil & grease, dissolved phosphorus, and TSS. It is apparent that the Tijuana River had significantly higher levels than all of the other stations for constituents that are associated with both untreated wastewater and highly urbanized land use patterns. The Tijuana River is treated during low flow conditions at the International Boundary Wastewater Treatment Plant, however, during storm conditions, water flows over the diversion weir and is discharged downstream. The mass loading station is located downstream of the diversion system and receives the storm flow. This would account for the high levels of constituents observed at this location. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-19 Analyte P-value Stations Toxicity Endpoints <0.001 TJ SR AH SM TC SDC SDR PC EC CC 33.3 83.3 100 100 100 100 100 100 100 100 Ceriodaphnia acute survival NOEC <0.001 TJ SR AH SLR SDR SDC PC EC CC TC 25 75 83.3 100 100 100 100 100 100 100 Ceriodaphnia chronic survival NOEC 0.022 TJ SR SDC CC SLR TC PC EC SDR AH 33.3 54.2 75 75 100 100 100 100 100 100 Ceriodaphnia chronic reproduction NOEC Bacteriological 0.008 TJ TC CC AH SLR SDR EC SR PC SDC 1,597,914 76,631 74,169 46,104 17,325 10,364 8,794 4,932 2,988 2,871 Enterococci MPN/100ml <0.001 TJ CC TC AH SLR EC SDR SDC PC SR 2,977,611 47,593 24,917 19,574 8,794 4,151 1,732 1,172 819 797 Fecal Coliforms MPN/100ml 0.002 TJ CC TC SDR AH EC SLR PC SR SDC 6,082,202 404,735 238,228 76,631 74,169 37,043 27,400 22,273 22,186 8,963 Total Coliforms MPN/100ml Wet Chemistry 0.001 TJ CC SDR AH EC TC SR SDC PC SLR 5.31 0.87 0.54 0.41 0.30 0.26 0.22 0.13 0.08 0.05 Ammonia As N* mg/l 0.011 SR SDC PC EC SLR AH TJ SDR CC TC 2953 2778 2391 2260 1861 987 985 478 357 280 Conductivity umhos/cm 0.011 EC SLR TJ CC AH SDC SR SDR PC TC 5.41 3.92 2.72 1.87 1.74 1.21 1.01 0.68 0.58 0.48 Nitrate As N mg/l 0.001 TJ CC TC AH EC PC SDC SDR SLR SR 3.99 1.93 0.77 0.50 0.50 0.50 0.50 0.50 0.50 0.50 Oil & Grease* 0.005 TJ AH CC TC SLR SR SDR PC SDC EC 1.56 0.68 0.64 0.46 0.28 0.28 0.26 0.25 0.14 0.10 Dissolved Phosphorus* mg/l 0.046 TJ TC AH CC SLR SDR SR EC PC SDC 2.06 1.28 1.25 0.87 0.66 0.52 0.43 0.39 0.37 0.26 Total Phosphorus mg/l <0.001 SR SDC PC EC SLR AH TJ SDR TC CC 2213 1571 1475 1278 1011 673 667 613 362 300 Total Dissolved Solids mg/l Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-20 Analyte P-value Stations 0.019 TJ TC AH CC SDR EC SLR SR PC SDC 3743 885 689 388 196 132 91 49 43 27 Total Suspended Solids mg/l Hardness 0.001 SR SDC PC EC SLR TJ AH SDR TC CC 919 740 695 626 528 476 345 272 203 110 Total Hardness mg CaCO3/l Non-significant results Hyalella (NOEC) 0.545 pH 0.085 Total Antimony All ND Dissolved Antimony All ND Selenastrum (NOEC) 0.471 Total Kjeldahl Nitrogen 0.069 Total Arsenic 0.481 Dissolved Arsenic All ND BOD 0.427 Total Organic Carbon 0.823 Total Cadmium 0.709 Dissolved Cadmium All ND COD 0.785 Turbidity 0.298 Total Chromium 0.202 Dissolved Chromium All ND Dissolved Organic Carbon 0.916 Chlorpyrifos All ND Total Copper 0.309 Dissolved Copper 0.569 Nitrite as N 0.156 Diazinon 0.107 Total Lead 0.106 Dissolved Lead 0.814 Surfactants 0.579 Malathion 0.332 Total Nickel 0.087 Dissolved Nickel 0.434 Total Selenium All ND Dissolved Selenium All ND Total Zinc 0.246 Dissolved Zinc 0.385 * Means contain ND values, see text for details Figure 13-12. Results of MLS Comparisons by Analysis of Variance (ANOVA). Among the bacterial indicators, there were distinct differences for fecal coliform densities (Figure 13-12). As with the toxicity endpoints, the Tijuana River MLS had statistically higher levels of fecal coliforms than the rest of the sites in the County. Enterococcus and total coliforms were also highest at the Tijuana River, but these were not statistically different from the other MLS, including Tecolote Creek, Chollas Creek, and the San Diego River. The Tecolote Creek and Chollas Creek MLS data were grouped with the Tijuana River MLS data for enterococci and total coliforms and indicated higher mean concentrations at these locations compared to the other MLS. The comparison of fecal coliform concentrations indicated an overall grouping (green and yellow bars overlap for most of the sites) which is consistent with the previous discussion regarding a regional bacteria issue. Consistent with the conclusions from the previous discussion of the comparison of the magnitude of exceedance of the WQO for TSS, the ANOVA results also indicate a significant difference for the Tijuana River, Tecolote Creek, and Aqua Hedionda Creek MLS. Furthermore, the conclusion that sediment as measured by TSS is a regional water quality issue is further evident by the overlapping of the green bar that includes all the other sites with Tecolote Creek and Agua Hedionda Creek. As shown on Figure 13-12, the mean concentration of nitrate at the Escondido Creek MLS was the highest of all sites, and is grouped with the San Luis Rey River, the Tijuana River, Chollas Creek, and Agua Hedionda Creek. With the exception of the Escondido Creek MLS, all other sites were grouped together as indicated by the green bar that overlaps the red line of the first group listed above. The ANOVA results for dissolved phosphorus indicate a similar grouping of higher mean concentrations for the Tijuana River, Agua Hedionda Creek and Chollas Creek MLS. Escondido Creek had the lowest mean concentration for this constituent. There was no significant difference between sites for total phosphorus. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-21 13.1.1.3 Cluster Results Multivariate cluster analysis was applied to the key constituents and the toxicity endpoints (in terms of NOEC values) for each MLS and sampling event. This approach groups the station/sampling events by the commonality of the constituent concentrations detected at each site. Likewise, it groups the constituents according to similar loadings at stations. Prior to the analysis the bacteriological measures were log10 transformed and the data for each COC was standardized by the overall mean value for each COC. The results of the cluster analysis are presented on Figure 13-13. Cluster analyses are performed to determine the degree of similarity among stations and/or storm events relative to the constituent concentrations for those events. They can be useful in assessing the characteristics of a site in relation to storm water runoff as well as providing information on the inter- relationships of the constituents. The results of the cluster analyses based on the wet-weather data from the past four years of monitoring data are presented in Figure 13-13. The size of the square in each cell of Figure 13-13 was determined by the constituent concentration at each station/storm event compared to the mean value for that constituent for all station/storm events monitored. Thus, large squares represent values that were greater than the mean concentration for the season and small squares represent values that were less than the mean. The colored boxes indicate the constituent groups that best-define each station cluster group. None of the storms from the Santa Margarita MLS were included in the cluster analyses because the analytical detection limits for several of the key constituents were higher than those used for the other sites and several constituents were not measured. The results of the cluster analysis are summarized as follows: • Purple Clusters – High Constituent Concentrations and Toxicity in Tijuana River – Consistent with the results of the magnitude of exceedance of the WQO and ANOVA comparisons, the results for the Tijuana River MLS have indicated significantly higher concentrations and continued water quality issues that include toxicity, bacteria indicators, metals, nutrients, and pesticides. These results confirm reported discharges of untreated sewage and runoff from highly urbanized drainage areas upstream of the MLS. One storm each from Agua Hedionda and from Chollas Creek were also members of this cluster group. The remaining clusters excluded Tijuana River since this site has been characterized for the highest concentrations for the constituents listed. • Yellow Clusters – Higher Concentrations of Metals and TDS– The first cluster highlights the higher concentrations of metals detected in Chollas Creek, Tecolote Creek and Agua Hedionda Creek. This representation is consistent with the magnitude of exceedance of the WQO comparison presented for total copper and zinc, which identified higher ratios for these same MLS. The highest exceedances were indicated for Chollas Creek. The second yellow cluster represents higher hardness and TDS concentrations compared to the mean for numerous MLS for monitoring periods predominantly over the 2003-2004 season. This is consistent with the magnitude of exceedance comparisons shown on Figure 13-1, which also indicate higher ratios for the 2003-2004 wet-season. The amount of rainfall during the 2003-2004 season was significantly less than the 2004-2005 season. However, as shown on Figure 13-1, the magnitude of exceedance ratios are not significantly different over the four years of monitoring. As discussed previously, TDS concentrations also exceeded the WQO in all MLS over the 2004-2005 wet- season with the exception of the Tecolote Creek, San Diego River, Chollas Creek, and Tijuana River MLS. Higher TSS at these sites appears to be a consistent issue. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-22 Figure 13-13. Results of Cluster Analysis for Wet Weather Data. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-23 • Pink Cluster – Higher Electrical Conductivity and Dissolved Lead in 2004-2005 – Higher electrical conductivity and dissolved lead compared to the mean are indicated for numerous watersheds for the 2004-2005 wet season. The February 2005 storm event is most represented, but this cluster also includes the October 2004 sampling event. The October event would represent a potential first flush phenomenon, whereas the February event may represent a high intensity rain event that mobilized these constituents. • Blue Cluster – Higher TSS, Metals, Pesticides and Nutrients – This cluster indicates a potential correlation of high TSS with other constituents where their concentrations are higher than other sites. As identified in the first yellow cluster, the wet-weather results for Chollas Creek indicate consistent higher metals concentrations. The ANOVA and magnitude of exceedance ratio results also indicated higher TSS concentrations for Tecolote Creek and Agua Hedionda Creek and corresponding higher Diazinon, copper, and zinc concentrations, which are also represented in this blue cluster. • Orange Cluster – Higher Hardness, TDS, and Electrical Conductivity – This cluster represents a potential correlation between TDS and conductivity, which also corresponded to a higher hardness value for numerous sites in the 2001-2002 monitoring period. Increased dissolved minerals in storm water will increase TDS, and depending on the charged nature of the dissolved mineral salts, will also increase conductivity. Higher hardness is a function of the concentration of carbonate species. As discussed previously, higher TDS may be due to greater contributions from groundwater/base flow during drier wet seasons in receiving waters where these base flows constitute a significant portion of the overall flow. The 2001-2002 and 2002-2003 seasons were drier than the 2004-2005 season. This overall cluster emphasizes the difference in watersheds between the Tijuana River and the rest of the County and also highlights differences between monitoring years. 13.1.2 Relationships Between Toxicity and Constituents of Concern The relationships between toxicity and constituents of concern (COC) have been evaluated by two methods. The first method presented below uses a multiple regression model to correlate changes in toxicity to changes in COC levels in the water. Data for all watersheds combined provide a wide range of both toxicity results and COC concentrations that is useful in providing general trends across the county and evaluating the effects of several COC at once. Sometimes thresholds of chemical concentrations are involved with toxicity whereby the organisms do not respond negatively until a certain chemical level is reached. Concentrations of COC above a specific threshold may no longer illicit a linear response in organism toxicity. Consequently, these COC detract from the regression model. Therefore, a second method, threshold analysis, was used to test relationships for COC with established thresholds. The threshold analysis uses COC levels reported to be toxic in the literature where available and compares them to COC levels in the storm water samples. Principal Components Analyses (PCA) Results PCA analyses were run for the 2004-05 COC to reduce the analyte list to a number that could be tested based on the number of sites and storm events. The PCA on the metal (dissolved and total) COC had 59% of the variance explained by the first component. The next two components were fairly close in explaining another 15% and 11% of the variance, respectively. These three components were used for Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-24 the multiple regressions. The first component was defined by dissolved copper, nickel, zinc and total antimony, cadmium, copper, and zinc. The second metal component was mainly composed of total chromium. Dissolved lead and total arsenic were the main contributors to metal component 3. The PCA on the physical and organic measures had 82% of the variance explained by the first four components. All four components were retained in the regression analyses. Component 1 was composed of ammonia, MBAS (surfactants), nitrite, and oil & grease. The second component represented the measures of biochemical oxygen demand (BOD), chemical oxygen demand (COD), as well as dissolved and total organic carbon. Conductivity, total dissolved solids (TDS), and total hardness were the main contributors to component 3 while total suspended solids (TSS) and turbidity dominated component 4. The retained PCA components, the pesticides Chlorpyrifos, Diazinon, and Malathion and the bacterial measures of total coliforms and enterococci (fecal coliforms were not included as they were 87% correlated with total coliforms) were used as regressors with each of the toxicity endpoints. A second set of multiple regressions was run using only the retained individual regressors and the main COC of each significant PCA component to determine which individual COC explained the toxicity results. Regression and Threshold Analyses Results 2004-05 This is the fourth year of monitoring at 10 mass loading stations (excluding the Santa Margarita River). Regression analyses indicated some different results from last year with regard to significant regressors. In the immediate past year (2003-04) significant regressors were dominated by the total metals and some nutrient measures (e.g., TKN) whereas previously Diazinon and TSS were dominant regressors. For the current year oil & grease, TDS, MBAS (surfactants), and ammonia were the significant regressors. The absence of Diazinon as a significant regressor may be due to the decreased concentrations observed in this monitoring year discussed previously (see Section 13.1.1). Ceriodaphnia dubia Survival Ceriodaphnia dubia survival toxicity, both acute and chronic, was only found in four samples (three at Tijuana River and one at Sweetwater River) during the 2004-05 monitoring season. Because there where no intermediate NOEC values for chronic survival toxicity between 50% and 100%, regression analysis was inappropriate and not performed. Regression was performed on the acute survival results with an R2 of 0.87; total chromium, ammonia, MBAS, and oil & grease were the main factors (Table 13-2 and Figure 13-14). The lowest literature value for Diazinon found to be toxic to a species related to Ceriodaphnia is 0.26 μg/L (21-day NOEC for D. magna) (Vershueren 1983). The literature value for Malathion toxicity to D. magna is 0.6 μg/L (21-day NOEC) (Vershueren 1983). In contrast to previous years, no correlation between toxicity and Diazinon or Malathion concentrations was found in the 2004-05 data. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-25 0123456 Oil & Grease (mg/l) 0 20 40 60 80 100 No Effect Concentration (%)0.2 0.3 0.4 0.5 0.6 0.7 MBAS (mg/l) 0 20 40 60 80 100 0246810 Ammonia as N (mg/l) 0 20 40 60 80 100 No Effect Concentration (%)0 0.004 0.008 0.012 0.016 Total Chromium (ug/l) 0 20 40 60 80 100 Figure 13-14. Relationships of Ceriodaphnia dubia acute survival with significant regressors from multiple regression analysis. Table 13-2. Multiple regression results. Toxicity Endpoint (NOEC) Prob > F R2 Significant Regressors* Ceriodaphnia dubia acute survival 0.0001 0.87 ammonia (-), MBAS (-), oil & grease (-), total chromium (-) Ceriodaphnia dubia chronic reproduction 0.0001 0.84 Enterococci (-), conductivity (+), oil & grease (-), TDS (-) * + indicates positive slope, - indicates negative slope Ceriodaphnia dubia Reproduction The regression for Ceriodaphnia reproduction had an R2 of 0.84 with conductivity, TDS, and oil & grease as significant regressors (Table 13-2 and Figure 13-15). Conductivity had a positive relationship with the NOEC (survival increases with greater concentrations); therefore this relationship may not be meaningful. None of the relationships appear to be very strong as seen in Figure 13-15. Threshold analyses with Diazinon at 0.26 μg/L and Malathion at 0.6 μg/L were not significant. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-26 0123456 Oil & Grease (mg/l) 0 20 40 60 80 100 No Effect Concentration (%)0 2000 4000 6000 Conductivity (umhos/cm) 0 20 40 60 80 100 100 10000 1000000 Enterococci (MPN/100 ml) 0 20 40 60 80 100 No Effect Concentration (%)0 1000 2000 3000 TDS (mg/l) 0 20 40 60 80 100 Figure 13-15. Relationships of Ceriodaphnia dubia reproduction with significant regressors from multiple regression analysis. Hyalella azteca Survival Regression analysis for Hyalella was not appropriate as only three samples elicited toxic responses. Threshold analysis was more appropriate for this endpoint. Threshold analysis for Diazinon and Malathion as described above failed to detect significant relationships and visual comparison of COC concentrations in Table 13-1 did not yield any obvious relationships. Selenastrum capricornutum Growth Selenastrum had one toxic response during the 2004-05 storm season so regressions were not performed. No significant relationships were found by threshold analysis with Diazinon or Malathion. Regression and Threshold Analyses Results 2001-05 Ceriodaphnia dubia Survival Ceriodaphnia survival, when analyzed with the four years combined, shows a strong relationship with Diazinon, dissolved phosphorus, and dissolved nickel for both acute and chronic tests (Table 13-3; Figure 13-16 and 13-17). The threshold analysis for Diazinon continues to be significant at a threshold of 0.26 Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-27 μg/L with 110 of 120 expected matches for acute survival and 109 of 120 expected matches for chronic survival. Dissolved nickel also shows a similar relationship to both acute (108 of 113 matches) and chronic (103 of 113 matches) survival at values above the threshold of 0.008 mg/L. Table 13-3. Multiple regression results for 2001-02, 2002-03, 2003-04, and 2004-05 combined. Toxicity Endpoint (NOEC) Prob > F R2 Significant Regressors* Ceriodaphnia dubia acute survival 0.0001 0.76 Diazinon (-), Chlorpyrifos (-), dissolved antimony (-), dissolved copper (-), dissolved nickel (-), dissolved phosphorus (-) Ceriodaphnia dubia chronic survival 0.0001 0.80 Diazinon (-), nitrite (-), dissolved nickel (-), dissolved phosphorus (+), dissolved copper (-), dissolved selenium (-) Ceriodaphnia dubia chronic reproduction 0.0001 0.69 Diazinon (-), Chlorpyrifos (-), dissolved phosphorus (+),dissolved nickel (-), nitrate (+), dissolved chromium (-),total zinc (+) Hyalella azteca acute survival 0.0001 0.56 TSS (-), dissolved zinc (-), total antimony (+), total cadmium (-) Selenastrum capricornutum 0.0001 0.23 conductivity (-),dissolved chromium (-) * + indicates positive slope, - indicates negative slope Unshaded results indicate a strong correlation. 01234 Dissolved Phosphorus (mg/l) 0 20 40 60 80 100 No Effect Concentration (%)0 0.010.020.030.04 Dissolved Nickel (mg/l) 0 20 40 60 80 100 0 0.040.080.120.16 0.2 Chlorpyrifos (ug/l) 0 20 40 60 80 100 0 0.2 0.4 0.6 0.8 1 Diazinon (ug/l) 0 20 40 60 80 100 No Effect Concentration (%) Figure 13-16. Relationships of Ceriodaphnia dubia acute survival with significant regressors from multiple regression analysis. Dashed line shows literature threshold. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-28 0 0.01 0.02 0.03 0.04 Dissolved Nickel (mg/l) 0 20 40 60 80 100 No Effect Concentration (%)00.40.81.21.6 Nitrite as N (mg/l) 0 20 40 60 80 100 01234 Dissolved Phosphorus (mg/l) 0 20 40 60 80 100 00.20.40.60.81 Diazinon (ug/l) 0 20 40 60 80 100 No Effect Concentration (%) Figure 13-17. Relationships of Ceriodaphnia dubia chronic survival with significant regressors from multiple regression analysis. Dashed line shows literature threshold. Ceriodaphnia dubia Reproduction Regression results for Ceriodaphnia reproduction were similar to those for survival (Table 13-2 and Figure 13-18). Diazinon, dissolved phosphorus, and dissolved nickel showed similar patterns with the NOEC as were found for survival. The patterns for the other regressors, although significant, contribute less visible information to the relationship with decreased reproduction. Threshold analysis for Diazinon resulted in a significant test, but lower results than for survival with 104 of 120 matches for Diazinon. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-29 01234 Dissolved Phosphorus (mg/l) 0 20 40 60 80 100 No Effect Concentration (%)0 0.01 0.02 0.03 0.04 Dissolved Nickel (mg/l) 0 20 40 60 80 100 0 0.04 0.08 0.12 0.16 0.2 Chlorpyrifos (ug/l) 0 20 40 60 80 100 00.20.40.60.81 Diazinon (ug/l) 0 20 40 60 80 100 No Effect Concentration (%) Figure 13-18. Relationships of Ceriodaphnia dubia reproduction with significant regressors from multiple regression analysis. Dashed line shows literature threshold. Hyalella azteca Survival Toxicity in Hyalella only occurred in 15 of 120 MLS/storms. Only one toxic response was at a NOEC of 25%, the others were 50%. While the multiple regression resulted in significant relationships (Table 13- 3), none of the relationships were strong ones. Selenastrum capricornutum Growth Tests on growth for Selenastrum showed toxic reactions in 13 of 105 MLS/storms. The multiple regression on the combined years resulted in a weak correlation (Table 13-3) with two COC. Summary of Statistical Analyses The single event and annual mean concentrations for key constituents and toxicity at the Tijuana River MLS were statistically different and had higher magnitude of exceedances of WQO compared to all the other MLS, particularly those associated with untreated wastewater and highly urbanized land use. The constituents that consistently exceeded the WQO include fecal coliform, TSS, turbidity, BOD, ammonia, total phosphorus, and Diazinon. This is a finding that has been consistent throughout the past four years Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-30 of monitoring. This MLS has also had the most consistent toxicity results with toxic reactions for all tests except those for Selenastrum. On a regional basis, TSS annual mean concentrations have exceeded the WQO in 7of the 11 MLS over the last four years indicating that TSS, which is an indicator of sediment loading, is a regional water quality issue. Across watersheds, the highest exceedances were observed for the 2004-2005 period which corresponds to the year of greatest precipitation. Larger and greater intensity storm events will mobilize a greater amount of sediment that would then correlate to greater TSS concentrations. Higher TSS may be associated with an increase in land disturbance activities in the watershed and increased impervious areas upstream of creek and river sections that may be subject to bank erosion from greater and more sustained peak flows. Temporal patterns in TSS concentrations indicate higher concentrations during greater intensity storm events. Notable long-term trends at other MLS include: • Bacteria - Results of regression analysis of wet-weather data for bacteriological indicators demonstrated increasing trends for enterococci in Tecolote Creek, the San Luis Rey River, and the Tijuana River, and for fecal coliform in the San Luis Rey River and Agua Hedionda Creek. Concentrations of fecal coliform were generally above the WQO. Concentrations at the MLS in the San Luis Rey River have increased from below to above the WQO. • Sedimentation -Increasing turbidity and TSS in Agua Hedionda Creek and increasing turbidity in Chollas Creek. Turbidity and TSS concentrations at these MLS were above the WQO. • Nutrients - Increasing nitrate concentration in the San Luis Rey River and the San Dieguito River. Increasing total and dissolved phosphorus concentrations in Agua Hedionda Creek and the San Dieguito River, and total phosphorus in Tecolote Creek. Concentrations of nitrate and dissolved phosphorus were below the WQO. • Pesticides - Diazinon concentrations indicate a significant decreasing trend for Escondido Creek, Peñasquitos Creek, Tecolote Creek, the San Diego River, and Sweetwater River. Concentrations have decreased from above to below the WQO. • Metals - Trend analysis based on regression analysis of the wet-weather data indicate no significant trends for total metals in more than one watershed with the exception of total lead. A decreasing trend in total lead concentrations was noted for Tecolote Creek and Chollas Creek. Cluster analysis showed the differences between the Tijuana River and the other MLS primarily, followed by differences between years, which may be related to the differing amounts of rainfall in the past four years. Relationships between Ceriodaphnia dubia toxicity and COC based on the four years of data showed strong relationships for increasing toxicity with higher concentrations of Diazinon, TSS, and dissolved nickel. Strong relationships based on the threshold analysis were also found for Diazinon. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-31 13.2 Storm Water Modeling 13.2.1 Static Storm Water Modeling Static storm water modeling, described here, predicts average flows and contaminant concentrations based on watershed characteristics. Dynamic modeling, covered later in this section, estimates how flow rates and concentrations change during a storm. Predicted pollutant loads and event mean concentrations (EMCs) expected from mass loading stations were calculated using a spreadsheet model. The static pollutant loadings model consists of a Microsoft ExcelTM spreadsheet that calculates annual pollutant loads expressed in pounds per year. The loadings and EMCs were estimated based upon land use types within the mass loading station watersheds, associated EMC values representative of each land use, and volume of runoff from the watershed. The spreadsheet was used to estimate annual runoff pollution loads and EMCs for the following constituents: nutrients (dissolved phosphorus and total Kjeldahl nitrogen); selected heavy metals (lead, copper, zinc, and cadmium); oxygen demand (BOD5 and COD) and total suspended solids (TSS). 13.2.1.1 Model Description The land use EMCs were calculated from results obtained from the first five monitoring years for residential, commercial, industrial, and open land use categories for all parameters. EMCs for parks and open land were based upon Nationwide Urban Runoff Program (NURP) values with the exception of lead, where more recent data were used (Walker 1989), and BOD, total copper, and total cadmium, for which NURP results were not available. Results from calculated EMCs from Los Angeles County based on data collected from 1994-2000 routine monitoring of land use stations were used for these parameters. No parks/open space land-use sites have been monitored under the current program because the program focuses on urban land uses. Federal Highway Administration data (FHWA 1990) were used for roadways. EMC input values used in the model are summarized in Table 13-4. Table 13-4. EMC Input Parameters for each Land Use Category, 2003-2004. Land Use Percent Impervious BOD (mg/L) COD (mg/L) TSS (mg/L) Diss. P (mg/L) TKN (mg/L) Total Pb (μg/L) Total Cu (μg/L) Total Zn (μg/L) Total Cd (μg/L) Park & Open/ Undeveloped/unknown 0.5% 12a 17a 69a 0.11a 0.79 a 23.0 b 15a 46a 0.38b Agriculture 0.5% 12a 17a 69a 0.11a 0.79 a 23.0 b 15a 46a 0.38b Residential 15.5% 17 93 196 0.31 2.17 23 34 276 0.67 Commercial 90.0% 19 90 111 0.30 2.11 16 27 254 0.75 Industrial 72.1% 15 66 131 0.36 1.76 31 31 143 0.71 Roadwayb 90.0% 9.70 103 142 0.170 1.781 23.0 52.0 368 2.00 a Based on data from Los Angeles County b Based on NURP, EPA 1983. c Based on Federal Highway Administration , “Pollution Loading and Impacts from Highway Storm Water Runoff, Volume3; Analytical Investigation and Research Report,” FHWA-D-88-008, McLean, Virginia, April 1990. All other values are based on the first five years of land use station monitoring, and represent the arithmetic mean values from the long-term data sets for each constituent by land use. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-32 The San Diego Association of Governments (SANDAG) geographic information system (GIS) database and the SANDAG 2000 Generalized Land Use maps were used to determine land use within the catchments of the mass loading sites. SANDAG data was supplemented with information from San Diego State University and USGS. Land uses within the monitored portions of these watersheds were summarized previously in this report. The model inputs include the percentage of impervious land coverage within each land use category, runoff coefficients for pervious and impervious areas, and average annual rainfall for each drainage basin. Percent impervious values were based upon literature values and URS Greiner Woodward Clyde data from studies throughout the country. For this analysis, pervious areas were assumed to have a runoff coefficient of 0.20 and impervious areas 0.95. Long-term isohyets were used to estimate average annual rainfall for each drainage basin. The data for San Diego County land use, annual rainfall distribution, and drainage areas contributing to runoff to the mass loading stations were geographically linked together in an ArcView® GIS as indicated in Figure 13-19. The total loading values for each mass loading station were determined by multiplying the contributing runoff volume from each land use type by the various input constituent land use based EMCs shown in Table 13-4. This total load is divided by the estimated total runoff volume as shown in the equation. The runoff volume for each land use type was found by factoring in average annual rainfall, total acreage, and percent of precipitation that would be expected to run off the land for each land use type. ∑ [ (Rainfalllanduse) * (Arealanduse) * (Clanduse) (Input EMClanduse) ] Total Load Estimated EMC = ∑ [ (Rainfalllanduse) * (Arealanduse) * (Clanduse) ] =Runoff Volume where C is the runoff coefficient for a particular land use type The northern area of the Santa Margarita Hydrologic Unit and the southern area of the Tijuana Hydrologic Unit were not covered in the SANDAG 2000 Land use GIS data. Land use information (1995) for the Mexican portion of the Tijuana Hydrologic Unit was obtained from the Center for Earth Systems Analysis Research at San Diego State University. Land use data (1980s) for the County of Riverside portion of the Santa Margarita Hydrologic Unit was obtained from the USGS. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-33 Figure 13-19. GIS data layer input into the EMC model. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-34 13.2.1.2 Model Results and Discussion The estimated mean concentrations, the mean measured concentrations and annual loads are shown on Figure 13-20 for visual comparison. These figures compare the estimated annual concentrations of various constituents with the actual measured concentrations found during the 2004-2005 monitored storm events. A value of one half the detection limit was used for measurements that resulted in undetectable levels of constituents. In general, the estimates summarized in the figures indicate that the primary factor influencing water quality is land use. That is, the water quality within a hydrologic unit is primarily a function of the runoff of the land use types that cover the largest area of that watershed. The utility of the model comparison to measured results at mass loading stations during storm events is to provide a comparison to anticipated results based upon land uses. If the measured results are significantly higher than the model results (EMC values), it suggests that there is a higher concentration of the COC in the watershed during storm events than expected. This would also be confirmed by comparison to historical measures within that watershed. Alternatively, when EMC values are higher than measured results it provides an additional tool to document reductions in COC loads that may be a result of BMPs within the watershed. This tool would also complement the long-term trend analysis that indicates COC reduction through time that may possibly be a result of a BMPs success. Estimated chemical oxygen demand (Figure 13-20, upper left) matched measured concentrations for most mass loading stations. However, measured COD values were much higher than estimated values at Chollas Creek, Agua Hedionda Creek, the San Diego River, and the Tijuana River during storm events, which may be indicative of a potential sewage spill or overflow. Other monitoring stations had lower variability and concentrations closer to the modeled value. Dissolved phosphorus (Figure 13-20, upper right) had measured EMC values that were higher than the modeled values. Measured values of dissolved phosphorus during all three events at the Tijuana River (TJR) and Agua Hedionda (AH) were well above the estimated concentrations. Estimated total suspended solid concentrations (TSS) (Figure 13-20, lower left) were very close to values measured during monitored storm events for many of the mass loading stations. The Tijuana River (TJR) and Agua Hedionda (AH) mass loading stations had a high degree of variability in TSS measurements between storms and all measured values were above estimated concentrations calculated from the model. Other stations had results that were often relatively low as estimated by the model. The model predicts slightly higher concentrations of total copper (Figure 13-20, lower right) from drainage areas that are highly urbanized. Most measure values were close to the predicted ones. However, the Chollas Creek (CC) mass loading station had a measured copper concentration during the October 17, 2004 storm that was several times higher than the estimated concentration. While the EMC model appears to often estimate concentrations close to actual concentration found during storm events. It doesn’t, however, capture the variability of concentrations observed between storms. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-35 Figure 13-20. Monitored vs. Modeled Event Mean Concentration Values. 0100200300400500600SLR AH EC SDC PC TC SDR CC SR TJRMass Loading StationConcentration (mg/l)10/17/200410/27/20042/11/20052/18/2005Model ValueChemical Oxygen Demand00.20.40.60.811.21.41.61.82SLR AH EC SDC PC TC SDR CC SR TJRMass Loading StationConcentration (mg/l)10/17/200410/27/20042/11/20052/18/2005Model ValueDissolved Phosphorus010002000300040005000600070008000SLR AH EC SDC PC TC SDR CC SR TJRMass Loading StationConcentration (mg/l)10/17/200410/27/20042/11/20052/18/2005Model ValueTotal Suspended Solids00.020.040.060.080.10.120.14SLR AH EC SDC PC TC SDR CC SR TJRMass Loading StationConcentration (mg/l)10/17/200410/27/20042/11/20052/18/2005Model ValueTotal Copper Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-36 A more accurate characterization of the typical concentrations of constituents running off land uses in San Diego County could result in greater refinement in this model. The model’s input land use EMC’s could also be modified through a trial and error process using 2001-2005 mass loading station and other available data to better fit San Diego County’s watersheds for future years. Improvements to the estimates from the model may provide a predictive tool to allow for estimating improvements to water quality from different BMPs. Future land use patterns can be also be explored to find their effects on the estimates of pollutant loads and concentrations. These observations help provide quantitative support to the intuitive concept that pollutant reduction strategies should: 1. Focus on improving water quality emanating from particular watersheds by developing and implementing BMPs that are designed to specifically reduce pollutants associated with certain land uses. 2. Focus sediment and pollutant accumulation monitoring activities below areas that drain large watersheds where the largest potential pollutant loads are expected. 3. Encourage pollution prevention, storm water educational outreach, and source control measures. It should be noted that uncertainty in the EMCs estimated for the study area results from inaccuracies in rainfall and land use data. The pollutant EMCs calculated for each land use and input into the model were computed from measured storm events assuming that the constituent concentrations are solely dependent on the land use characteristics of a given basin and that runoff from similar land uses throughout the study area has the same water quality. 13.2.2 Water Quality Variability during Storm Events The previous model discussed is a static model that estimates the typical average loads and concentrations. A more accurate model would need to account for variations of water quality during each storm event. This dynamic model would require discrete measurements of water quality during a storm event. On March 22, 2005, the mass loading station at Agua Hedionda Creek was sampled and analyzed during eight separate periods during the storm. The water quality results from the event are shown in Table 13-5. The highest values of each constituent observed during the storm event are highlighted in yellow. It is clear that different constituents reach their peak values at different times during the hydrograph. This is indicated more clearly in Figure 13-21. Dissolved solids and some nutrients had the highest values after the rain begins but before the runoff has reached its peak. The maximum values of total metals, suspended solids, and turbidity coincided with the hydrograph peak. The trend in turbidity can easily been seen in the picture of the series of sample containers next to the hydrograph. Indicator bacteria measurements varied greatly and did not show any clear pattern in relation to the hydrograph. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-37 Table 13-5. Discrete Water Quality Results at Agua Hedionda Creek, March 22, 2005. 3/22/05 18:55 3/22/05 20:26 3/22/05 21:05 3/22/05 21:35 3/22/05 22:55 3/23/05 0:20 3/23/05 9:05 3/23/05 9:35 ANALYTE AH4 AH5 AH6 AH7 AH8 AH9 AH10 AH11 Total Suspended Solids 24 432 389 500 1560 1150 463 110 Turbidity 8.55 30.1 35.4 65.3 192 177 116 58.5 Total Dissolved Solids 1200 879 526 346 425 321 404 801 Hardness (Total) 696 457 259 194 322 264 264 451 Copper 0.00375 0.009 0.00825 0.00725 0.01375 0.01175 0.00925 0.00475 Lead 0.001 0.002 0.002 0.0025 0.006 0.005 0.0035 0.001 Nickel 0.0045 0.007 0.006 0.0045 0.009 0.0055 0.005 0.004 Zinc 0.01 0.0185 0.022 0.0205 0.056 0.0385 0.03 0.01 Ammonia as N 0.050.260.050.050.050.050.050.05 Nitrate as N 3.81 0.67 0.8 0.54 0.46 2.26 1.25 1.85 Phosphate, Dissolved as P 0.1 0.19 0.28 0.11 0.22 0.36 0.34 0.18 Phosphorus, Total 0.13 0.38 0.41 0.81 0.45 0.5 0.57 0.41 Total Kjeldahl Nitrogen 2.5 5.2 3.3 3.7 5.1 3.4 2.2 1.5 Total Coliform 7,000 70000 22,000 30,000 80,000 50,000 170,000 110,000 Fecal Coliform 5,000 30000 14,000 5,000 22,000 23,000 13,000 11,000 Enterococcus 911 4611 4,352 6,131 5,806 4,568 4,284 1,624 0 20 40 60 80 100 120 140 160 3/22/2005 18:00 3/22/2005 20:00 3/22/2005 22:00 3/23/2005 0:00 3/23/2005 2:00 3/23/2005 4:00 3/23/2005 6:00 3/23/2005 8:00 3/23/2005 10:00Flow (cfs)Flow Sampling Times Highest Nitrate, Hardness, TDS Highest Ammonia,TKN, COD, Fecal Coliform Highest Total Phosphorus, EnterococcusHighest TSS Cu, Lb, Ni, ZnHighest Dissolved PhosphateHighest Total Coliform Figure 13-21. Hydrograph of Constituents during the March 22, 2005 storm event. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-38 The water quality pattern from Agua Hedionda was compared to the results from discrete water quality sampling during the previous year at Chollas Creek and the San Diego River. The comparison indicated water quality patterns that were unique to each watershed. Better understanding the relationship between the hydrograph and water quality can assist in more accurate models of water quality, suggest potential sources of pollutants, and provide information to develop BMPs to address water quality concerns. 13.3 Dry Weather Data Analysis Results The data used in this assessment was collected from May 1 through September 30, 2004. Among individual watersheds and jurisdictions, the number of sites monitored and the sampling frequency varied. Several reasons that account for this variability between watersheds are the number of jurisdictions implementing the program, the number of sites monitored by each individual jurisdiction, and the number of sub-watersheds. In each of the monitored watersheds, the number of exceedances also varied, resulting in a range of total exceedances per watershed from 2 for the Tijuana River area to as many as 133 for Carlsbad. During the 2004 monitoring period, 485 samples exceeded established water quality objectives (WQO). This sample volume has increased significantly since the 2003 monitoring period, when 373 samples exceeded. Table 13-6 shows the number of exceedances of each parameter per watershed in 2004. For all parameters combined, there were a total of 485 exceedances throughout the watersheds. The parameter which most frequently exceeded was total coliform, which accounted for 114 (23.5%) of all exceedances. Turbidity and enterococcus were the next highest, with respective contributions of 15.9% and 12.6%. Other parameters which each individually contributed 10-5% of the exceedances were ammonia, nitrate, orthophosphate, and fecal coliform (in descending order). The remaining parameters contributed to less than 5% of the total exceedances combined (conductivity, pH, dissolved copper, MBAS, Diazinon, oil and grease, dissolved cadmium, and Chlorpyrifos). There were no exceedances of dissolved lead or zinc. Land Use Water Quality Summary Major land use categories including residential, commercial, agriculture, industrial, and parks offered valuable information regarding the parameters that frequently exceeded action levels. Other land use categories are not summarized in this section due to the limited available information (small sample size) or lack of exceedances. These include rural residential, open space, and unspecified. Table 13-7 shows the land use categories that accounted for 95.9% of the total exceedances. It should be noted that categories with more sampling stations (i.e., residential) will likely account for a larger percent of the total exceedances simply due to the larger potential sample volume. As stated above, the predominant parameter was total coliform, followed by turbidity and enterococcus. Interestingly, the residential and commercial land uses have a similar pattern of COCs, whereas those of the agriculture, industrial, and parks land uses are distinctly unique. A full listing of COC by land use for the entire County for 2004 is found in Appendix D.1. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-39 Table 13-6. Dry Weather Exceedance Matrix (2004). AnalyteSanta Margarita RiverSan Luis Rey RiverCarlsbadSan DieguitoPeñasquitosMission BaySan Diego RiverPueblo San DiegoSweetwater Otay Tijuana Grand TotalpH 0 1 5 0 0 1 3 0 2 1 0 13Turbidity 1 4 18 11 7 5 9 13 2 5 2 77Conductivity 0 0 6 0 1 0 0 2 5 2 0 16Nitrate (NO3-N) 6 5263 0 0 30 3 00 46Ammonia (NH3-N) 0 7136 3 0 85 0 50 47Orthophosphate (PO4-P) 0 0 9 7 4 2 6 10 1 2 0 41MBAS 0 0 1 0 1 0 2 4 1 1 0 10Oil & Grease 1 0 0 0 0 0 0 2 1 0 0 4Cadmium, Diss 0 0 0 0 0 1 0 1 0 0 0 2Copper, Diss 0 0 0 1 5 3 3 1 0 0 0 13Lead, Diss 0 0 0 0 0 0 0 0 0 0 0 0Zinc, Diss 0 0 0 0 0 0 0 0 0 0 0 0Diazinon 0 1 1 1 0 2 1 0 0 0 6Chlorpyrifos 0 0 0 0 0 0 1 0 0 0 1Total Coliform 0 7 32 8 10 4 20 12 13 8 0 114Fecal Coliform 0 1 9 3 1 1 6 7 2 4 0 34Enterococcus 0 2 13 4 9 4 12 11 1 5 0 61Number of Exceedances 8 27 133 44 42 21 74 70 31 33 2 485 Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-40 Table 13-7. COC by land use category (2004 dry weather monitoring data). Land Use Category % of Total Exceedances COC in descending order of prevalence Residential 53.2 T. coliform>turbidity>enterococcus>orthophosphate>ammonia>f.coliform>nitrate Commercial 28.0 T. coliform>turbidity>enterococcus>ammonia> F. coliform>orthophosphate>nitrate Agriculture 5.4 Nitrate>turbidity>t.coliform>ammonia>enterococcus>f.coliform=oil&grease Industrial 5.2 T. coliform>enterococcus=turbidity>ammonia= dissolved copper>conductivity>f. coliform Parks 4.1 Turbidity>t. coliform>ammonia=conductivity= enterococcus=nitrate=oil&grease Comparison of current data to that collected in 2002 and 2003 reveals several clear trends in the frequency of various contaminant exceedances based on major land use categories. Table 13-8 shows three years of data for each of the most commonly exceeded parameters, and ranks them according to frequency of exceedance relative to the other parameters. Data for the parks land use as an independent category was not available for 2002 and 2003 and is not included. Parameters with the same numerical ranking for the same year were exceeded at an equal frequency. In comparing residential, commercial, industrial, and agricultural land uses, it is apparent that total coliform has frequently exceeded water quality objectives during the past three years of monitoring. Specifically for the residential and commercial categories, total coliform has been the first ranked COC during all three years. Also notable are the frequent exceedances for fecal coliform, enterococcus, and turbidity. Though it did not appear as a priority COC for any of the land uses in 2004, fecal coliform ranked second in 2003 for residential and commercial, and third for residential (2002), industrial (2002 and 2003), and agriculture (2003). Enterococcus was also consistently high, with rankings of first for commercial in 2002, second for industrial (2003 and 2004) and residential (2002), and third for residential (2003 and 2004) and commercial (2004). Turbidity was the second most frequently exceeded parameter for all the land uses in 2004. In addition, it was ranked second in 2003 for industrial and agricultural land uses. In the residential category, total coliform has been the dominant COC for all three years of data. Frequency of fecal coliform exceedance has significantly decreased from 2003 to 2004, but further analysis is required to confirm this trend. Enterococcus has consistently exceeded, only showing a slight decrease in ranking from second to third from 2002 to 2004. Turbidity has also exceeded in the residential category, but to a lesser degree than the bacterial indicators. As with residential land use, total coliform has been the primary COC during all three years for the commercial land use category. Enterococcus has also shown notable exceedances, ranking first in 2002 and third in 2004. Fecal coliform ranked second in 2003, but appears to be a less prominent COC than in the residential category. Other parameters that have ranked second in the commercial category include turbidity (2004) and ammonia (2002). Conductivity consistently ranked third through 2002-03, while oil and grease also ranked third in 2002. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-41 Table 13-8. COC ranking by land use category (2002 – 2004 dry weather monitoring data). Land Use Parameter Year Residential Commercial Industrial Agriculture Bacteria 2004 1 1 1 3 2003 1 1 1 3 Total coliform 2002 1 1 2 * 2004 6 4 5 6 2003 2 2 3 3 Fecal coliform 2002 3 3 * 2004 3 3 2 5 2003 3 5 2 Enterococcus 2002 2 1 * Physical Parameters 2004 2 2 2 2 2003 4 2 2 Turbidity 2002 4 * 2004 4 2003 3 3 Conductivity 2002 3 1 * Chemistry 2004 5 4 3 4 2003 Ammonia 2002 6 2 3 * 2004 7 6 1 2003 5 6 3 Nitrate 2002 6 * 2004 4 5 2003 6 3 Orthophosphate 2002 * 2004 6 2003 4 2 1 Oil and Grease 2002 3 3 * 2004 2003 4 Diazinon 2002 5 * * data not available The industrial land use category frequently exceeded for total coliform, with rankings of first for the past two years and second for 2002. Enterococcus ranked equally as second with turbidity for both 2003 and 2004, though determination of an association between these parameters for the industrial land use category would require further analysis. Oil and grease was also equally ranked as second in 2003. Parameters that ranked as third most frequently exceeded include fecal coliform (2002-03), ammonia (2002 and 2004), orthophosphate (2003), and oil and grease (2002). For the agricultural land use category, data was only available for 2003 and 2004. Based on these two years of data, indicator bacteria appear as a less prominent COC for agriculture. Total coliform ranked third for both years, while fecal coliform ranked third in 2003 and sixth in 2004. Enterococcus was only identified as a minor COC, ranking fifth most frequently exceeded in 2004. More notably was the prominence of nitrate, with rakings of first for 2004 and third for 2003. Turbidity ranked second in both 2003 and 2004, while conductivity ranked third in 2003. As with the industrial land use category, oil and grease appeared as a COC for agriculture, ranking first in 2003 and sixth in 2004. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-42 The potential benefits of annually updating the list of COC by land use category are: • the ability to assess the effectiveness of structural BMPs • the ability to select non-structural BMPs (outreach) • customizing inspections • predicting water quality impacts • determining overall changes in the prevalence of COCs In future years, the dry weather data may provide an indication of changes in pollutant types as the storm water program matures. Conveyance Type Water Quality Summary The Municipal Separate Storm Sewer System (MS4) conveyance type at each dry weather sampling location was logged by each jurisdiction. In 2004, the conveyance types and construction materials were more narrowly defined to allow for fewer categories. Although the dry weather data points are more representative of a single data point rather than the overall watershed, the analysis by conveyance type may provide additional use to the jurisdictions in evaluating dry weather action level exceedances. The 8 conveyance types are listed Table 13-9, along with the rate of exceedances that were found for each type during the 2004 monitoring period. The table also provides COC that exceeded WQO in descending order for each conveyance type. A full listing of COC by MS4 conveyance type is found in Appendix D.2. Table 13-9. COC by MS4 conveyance type (2004 dry weather monitoring data). MS4 Conveyance Type Number of Sites Exceedance Rate for All COC (%) COC in descending order of prevalence Outlet 133 11.1 T.coliform>enterococcus>turbidity>orthophosphate> ammonia>f.coliform Natural Creek 100 3.8 Nitrate>turbidity>t.coliform>conductivity>ammonia= enterococcus=f.coliform Concrete Channel 45 9.0 T.coliform>pH>enterococcus>nitrate=orthophosphate> ammonia Open Channel 34 6.7 T.coliform>turbidity>nitrate>ammonia>f.coliform=pH Earthen Channel 22 3.3 T.coliform>turbidity>enterococcus=pH>ammonia= orthophosphate Manhole 13 15.6 T.coliform>enterococcus>ammonia>f.coliform=turbidity> orthophosphate Catch Basin 9 1.6 Ammonia>f.coliform=t.coliform>enterococcus=turbidity> conductivity=nitrate=orthophosphate Gutter 1 23.5 MBAS=pH=t.coliform=turbidity Based on the 8 conveyance types, sites were categorized by construction material as either natural or manmade. Figure 13-22 represents analyte exceedances as a proportion of the sites where each parameter exceeded, based on these two conveyance types. Representing the data in this way allows for the identification of the most prevalent pollutants by type of MS4 conveyance system. The natural conveyance systems had notable exceedances for total coliform, turbidity, and nitrates, with proportions of 10%, 18%, and 20%, respectively. About half of the sampling sites for natural conveyances were associated with agricultural or rural residential land uses which may account for the higher frequencies for nitrate; the higher turbidity is likely due to the potential for erosion in earthen waterways. The manmade conveyance systems had exceedances at 10% or more stations of seven parameters. Ammonia, nitrate, and orthophosphate exceeded at 10-20% of the sites, while turbidity exceeded at Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-43 approximately 27% of the sites. The fecal coliform WQO was exceeded at 13% of the sites, whereas total coliform exceeded the WQO at 42% of the sites and 23% of sites had exceedances of enterococcus. The two parameters that consistently exceeded throughout all conveyance types were total coliform and turbidity. The potential benefits of annually updating the list of COC by MS4 conveyance type are: • selecting BMPs for each type based on pollutants found • selecting cleaning procedures or methods to target pollutants by MS4 type • using land use and conveyance type COC data to minimize water quality impacts from new development • prioritizing cleaning frequency of MS4 based on COC in the sub-watershed and/or 303(d) listings 0 0.1 0.2 0.3 0.4 0.5 Proportion of Sites with Analyte Above Action Level Manmade Natural Dissolved Zinc Dissolved Lead Dissolved Copper Dissolved Cadmium Surfactants Ammonia Nitrate Phosphate Oil and Grease pH Conductivity Turbidity Chlorpyrifos Diazinon Enterococcus Fecal coliform Total coliform Figure 13-22. Monitoring sites with analytes above the action level by conveyance type. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-44 13.4 Rapid Stream Bioassessment Results 13.4.1 Results and Discussion The results of the October 2004 and May 2005 stream bioassessment surveys are discussed below. Each survey is summarized separately. Monitoring reaches are usually described by the stream name and the nearest cross street. For ease of interpretation in the discussion, the full name of each site is used; in the tables, the site initials are used. An additional discussion includes an analysis of bioassessment results since the beginning of the study in May 2001. A complete discussion of the objectives, approach, materials, and methods and analyses is presented in Section 3.2. Appendix B.1-1 lists all of the monitoring sites sampled from May 2001 through May 2004, and Appendix B.1-2 presents photographs that characterize each monitoring reach. A complete systematic listing of the benthic invertebrates identified at all stations and replicates is presented in Appendix B.2, and includes the assigned tolerance value (TV) and functional feeding group (FFG) of each taxa. The ranked total abundances for each species at all sampling sites combined are presented in Appendix B.3. Appendix B.4 lists the percent composition of the top five most abundant taxa for each monitoring reach. With the exception of some beetles, nearly all of the insects identified in the program were in the larval and pupal stages of development, which metamorphose into an aerial adult form. Nearly all of the non-insect taxa are aquatic for their entire life cycle. 13.4.1.1 Regional Benthic Community Structure October 2004. Summing all stations in the program, a total of 110 taxa were identified from 18,460 individual organisms (Appendix B.3-1). The five most abundant taxa, in descending order were the black fly, Simulium; Chironomid midges; the amphipod, Hyalella; Ostracods (seed shrimp), and Oligochaetes (earthworms). Simulium was the dominant taxon at six of the sites, and Chironomids were the dominant taxon at three of the sites (Appendix B.4-1). The order Diptera (true flies) had the greatest number of different taxa with 30 taxa identified (Appendix B.2-1). Nineteen taxa of Coleoptera (beetles) and fourteen taxa of Trichoptera (caddisflies) were identified. May 2005. Summing all stations in the program, a total of 91 taxa were identified from 21,534 individual organisms (Appendix B.3-2). The five most abundant taxa, in descending order were the black fly, Simulium; the mayfly, Baetis; Chironomid midges; Oligochaetes, and the mayfly, Fallceon quilleri. Simulium was the dominant taxon at 10 of the sites, and Baetis was the dominant taxon at 7 of the sites (Appendix B.4-2). The order Diptera had the greatest number of different taxa with 24 taxa identified (Appendix B.2-2). There were 14 taxa of Coleoptera, and 11 taxa of Trichoptera identified. Benthic Invertebrate Community Metrics Benthic macroinvertebrate community mean metric values for each monitoring site are presented in Appendix B.5 and are summarized below. A brief description of the metrics and what they signify about the composition of the benthic community are given in Table 13-10. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-45 Table 13-10. Bioassessment Metrics Used to Characterize BMI Communities. BMI Metric Description Response to Impairment Richness Measures Taxa Richness Total number of individual taxa Decrease Coleopteran Taxa* Number of taxa in the insect order Coleoptera (beetles) Decrease EPT Taxa* Number of taxa in the Ephemeroptera (mayfly), Plecoptera (stonefly) and Trichoptera (caddisfly) insect orders Decrease Dipteran Taxa Number of taxa in the insect order Diptera (true flies) Increase Non-Insect Taxa Number of non-insect taxa Increase Predator Taxa* Number of taxa in the predator feeding group Decrease Composition Measures EPT Index Percent composition of mayfly, stonefly, and caddisfly larvae Decrease Sensitive EPT Index Percent composition of mayfly, stonefly, and caddisfly larvae with tolerance values between 0 and 3 Decrease Shannon Diversity Index General measure of sample diversity that incorporates richness and evenness (Shannon and Weaver 1962) Decrease Margalef Diversity Measure of sample diversity weighted for richness Decrease Tolerance/Intolerance Measures Tolerance Value Value between 0 and 10 of individuals designated as pollution tolerant (higher values) or intolerant (lower values) Increase Dominant Taxon Percent composition of the single most abundant taxon Increase Percent Chironomidae Percent composition of the tolerant dipteran family Chironomidae Increase Percent Intolerant Organisms* Percent of organisms in sample that are highly intolerant to impairment as indicated by a tolerance value of 0, 1 or 2 Decrease Percent Tolerant Organisms Percent of organisms in sample that are highly tolerant to impairment as indicated by a tolerance value of 8, 9 or 10 Increase Percent Tolerant Taxa* Percent of taxa in sample that are highly tolerant to impairment as indicated by a tolerance value of 8, 9 or 10 Increase Percent Non-insect Organisms Percent of organisms in sample that are not in the Class Insecta Increase Percent Non-insect Taxa* Percent of taxa in sample that are not in the Class Insecta Increase Functional Feeding Groups (FFG) Percent Collector- Gatherers* Percent of macrobenthos that collect or gather fine particulate matter Increase Percent Collector-Filterers* Percent of macrobenthos that filter fine particulate matter Increase Percent Scrapers Percent of macrobenthos that graze upon periphyton Increase Percent Predators Percent of macrobenthos that feed on other organisms Variable Percent Shredders Percent of macrobenthos that shreds coarse particulate matter Decrease Percent Other Percent of macrobenthos that are parasites, macrophyte herbivores, piercer herbivores, omnivores, and xylophages Variable Abundance Estimated Abundance Estimated number of organisms in entire sample Variable *indicates metrics used to calculate the Index of Biotic Integrity Source: modified from SDRWQCB 1999 Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-46 Taxa Richness October 2004. Taxonomic richness at the urban influenced monitoring sites ranged from a low of 9 different taxa at Sweetwater River at Bonita Road to 24 different taxa at Green Valley Creek at West Bernardo Way (Appendix B.5-1). Taxa richness at the reference sites ranged from 27 to 33 different taxa. May 2005. Taxonomic richness ranged from a low of 7 different taxa at Tijuana River at Dairy Mart Road to 17 different taxa at Agua Hedionda Creek at El Camino Real and Santa Margarita River on Camp Pendleton (Appendix B.5-2). Taxa richness at the reference sites ranged from 14 to 29 different taxa. Species Diversity and Dominance October 2004. Shannon Diversity values (weighted for evenness of distribution) at the urban influenced sites ranged from 1.2 at Sweetwater River at Bonita Road to 2.7 at San Diego River in Mission Trails Park (Appendix B.5-1). Margalef Diversity values (not weighted for evenness) ranged from 1.5 at Sweetwater River at Bonita Road to 4.0 at Green Valley Creek at West Bernardo Way. Dominance by a single taxon ranged from 17% Chironomids at San Diego River in Mission Trails Park to 62% Simulium at Santa Margarita River at Camp Pendleton. Shannon diversity values at the reference sites ranged from 2.4 to 2.6, and Margalef diversity values ranged from 4.1 to 5.1. May 2005. Shannon Diversity values at the urban influenced sites ranged from to 0.8 at San Dieguito River at Del Dios Highway to 1.8 at Chollas Creek at Federal Blvd. and San Luis Rey River at Benet Road (Appendix B.5-2). Margalef Diversity values ranged from 0.9 at San Dieguito River at Del Dios Highway to 2.6 at Agua Hedionda at El Camino Real and Santa Margarita River on Camp Pendleton. Dominance by a single taxon ranged from 31% Oligochaetes at San Luis Rey River at Benet Road to 75% Simulium at San Dieguito River at Del Dios Highway. Shannon diversity values at the reference sites ranged from 1.3 to 2.2, and Margalef diversity values ranged from 2.3 to 4.5. EPT Taxa EPT taxa are the benthic macroinvertebrates in the orders Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies). These orders of insect are considered separately in the analysis because they contain many taxa that are sensitive to disturbance and their presence usually indicates good stream habitat quality (note: a modified EPT index is sometimes considered, which eliminates the moderately tolerant EPT taxa such as Baetid mayflies and Hydropsychid caddisflies). October 2004. The cumulative number of EPT taxa at the urban influenced sites ranged from 0 at Rose Creek near Highway 52 to 8 at Santa Margarita River at Willow Glen Road (Appendix B.5-1). Baetid mayflies were the most abundant of the EPT taxa, and were present at 18 of the monitoring sites (Appendix B.3-1). The number of EPT taxa at the reference sites ranged from 8 to 16. Santa Margarita River at Willow Glen Road had the highest overall EPT%, where they comprised 71% of the benthic community due to high numbers of Hydropsychid caddisflies and Baetid mayflies. Sensitive EPT taxa (tolerance value 0-3) were present at all of the reference sites, plus four of the non-reference sites. The sensitive caddisfly, Tinodes, was present at San Dieguito River-Del Dios Highway and Santa Margarita River-Willow Glen Road, and the sensitive caddisfly, Oxyethira, was present at these two sites as well as Green Valley Creek at West Bernardo Road and San Diego River near Morena Blvd. (Appendix B.2-1). May 2005. The cumulative number of EPT taxa at the urban influenced sites ranged from zero at Tijuana River at Dairy Mart Road to five at Escondido Creek in Elfin Forest and Santa Margarita River on Camp Pendleton (Appendix B.5-2). The number of EPT taxa at the reference sites ranged from 6 to 16. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-47 Percent EPT taxa were highest at Chollas Creek at Federal Blvd. and Santa Margarita River at Willow Glen Road, where they comprised 59% of the community. The mayfly, Baetis, was the most abundant of the EPT taxa, and was present at all of the monitoring sites except the Tijuana River, and was the most abundant taxon at seven of the monitoring sites (Appendix B.3-2). Sensitive EPT taxa (tolerance value 0- 3) were present at the three reference sites and single individual of the caddisfly, Oxyethira, was present at Campo Creek in Campo. Tolerance Measures For most stream macroinvertebrates, a tolerance value has been determined for each taxon through prior experience with the animals’ life history (e.g., Hilsenhoff 1987). Tolerance values range from 0 for animals highly sensitive to impairments, to 10 for animals that are highly tolerant to impairments. It should be noted that tolerance values of organisms identified to the family or genus level are a mean of the taxa within that taxonomic level. The presence of impairment tolerant animals does not always imply impairment (SDRWQCB 2001), but the presence of intolerant animals is unlikely when impairment has occurred. October 2004. Mean tolerance values for the urban influenced sites ranged from 5.0 at Santa Margarita River at Willow Glen Road to 7.4 at Campo Creek in Campo (Appendix B.5-1). Mean tolerance values at the reference sites ranged from 3.9 to 4.1. Intolerant organisms (tolerance value 0-2) were present at all of the reference sites, and were most prevalent at the Doane Creek site, where they comprised 44% of the benthic community. Santa Margarita-Willow Glen Road was the only urban influenced site with highly intolerant organisms present, where the caddisfly, Tinodes, comprised 1% of the community. Percent tolerant organisms (tolerance value 8-10) ranged from 2% at Buena Vista River at College Blvd. to 80% at Campo Creek in Campo, primarily due to high numbers of Sphaeriid clams and Ostracods. May 2005. Mean tolerance values for the urban influenced sites ranged from 5.0 at Santa Margarita River on Camp Pendleton to 6.9 at Sweetwater River at Bonita Road (Appendix B.5-2). Mean tolerance values at the reference sites ranged from 4.4 to 5.6. Highly intolerant organisms (tolerance value 0-2) were present at all of the reference sites, but were not collected at any of the urban influenced sites. Intolerant organisms were most prevalent at Reference-Doane Creek, where they comprised 31% of the benthic community. Percent tolerant organisms (tolerance value 8-10) ranged from 0% at San Dieguito River on Del Dios Highway and Santa Margarita-Willow Glen Road to 48% at Sweetwater River at Bonita Road. Functional Feeding Groups As with tolerance values, functional feeding group (FFG) designations have been determined through prior life-history research of each genus or species. Making determinations of water quality based on feeding group composition can be problematic, but there are some generalizations that can be made. The collector-gatherer and collector-filterer feeding groups feed on fine particulate organic matter and will increase in response to impairment. The shredder feeding group feeds by shredding coarse particulate organic matter such as leaves, and predators prey on other stream organisms, and these two groups generally decrease in response to impairment. The herbivore and omnivore feeding groups vary in their response to impairment. Dragonfly and Damselfly Naiads Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-48 October 2004. Benthic invertebrates in the collector-gatherer feeding group dominated 14 of the 23 monitoring sites in the region (Appendix B.5-1). Of the remaining sites, collector-filterers were dominant at seven of the sites, including two of the reference sites. The most abundant collector-gatherer taxa were Chironomid midges, the amphipod, Hyalella, and Ostracods (Appendix B.2-1). The most abundant collector-filterer was the black fly, Simulium. Predators were most abundant at San Luis Rey River at Benet Road, where Corixids (water boatmen) comprised 47% of the community. Shredders were abundant only at the Doane Creek reference site. Scrapers were abundant only at the Rose Creek site where high numbers of the snails, Fossaria and Physa, were collected. May 2005. Functional feeding group compositions were similar to the October 2003 survey. Benthic invertebrates in the collector-gatherer feeding group dominated 17 of the monitoring sites in the region, and collector-filterers dominated the other sites (Appendix B.5-2). Predators were present in much lower numbers throughout the study area compared with the October survey, a seasonal trend that has been consistently observed in the past. Estimated Total Abundance The estimated total abundance is the total number of animals estimated to be in the sample if the entire sample had been sorted. In rapid bioassessment programs, usually a fraction of the entire sample is processed and the percent volume of the fraction sorted is estimated. Then, a total abundance number is calculated for the entire sample. This is used to estimate the number of animals living in 1 ft2 of benthic habitat. Response to moderate habitat impairment is often indicated by an increase in total abundance (by highly tolerant organisms) with a corresponding decrease in taxa richness and diversity; however, severe impairment can result in a catastrophic decrease in abundance. October 2004. Estimated abundance values ranged from 17 animals per ft2 at Los Peñasquitos Creek at Cobblestone Creek Road to 913 animals per ft2 at Escondido Creek-Harmony Grove Bridge (Appendix B.5-1). May 2005. Estimated abundance values ranged from 5 animals per ft2 at Tijuana River at Dairy Mart Road to 4060 animals per ft2 at San Dieguito River on Del Dios Highway (Appendix B.5-2). Overall abundances in the May survey were generally much higher than in October. 13.4.1.2 Physical Habitat and Water Quality Physical habitat quality scores for each monitoring reach are presented in Appendix B.6. The ten parameters are scored on a 0 to 20 scale, thus 200 is the highest possible score. The scores are assigned in a qualitative manner, so some variation among field biologists may be expected, and small differences in scores are not relevant. Large scale differences in habitat quality, however, are important when considering colonization potential by benthic macroinvertebrates. The physical habitat of each monitoring reach is discussed in greater detail in Sections 4 through 12. Water quality measures taken included pH, specific conductance, temperature, dissolved oxygen, and chlorophyll. Impairment is generally indicated by low pH, high conductance, low dissolved oxygen, and high chlorophyll. Historical analysis of bioassessment samples has shown that specific conductance has the greatest correlation to impaired benthic communities of the water quality parameters taken during bioassessment sampling (MEC-Weston unpublished data). October 2004. Total physical habitat quality scores ranged from 84 (marginal) at Agua Hedionda Creek-El Camino Real to 182 (Optimal) at Escondido Creek in Elfin Forest (Appendix B.6-1). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-49 Water quality data is presented in Appendix B.7-1. Values of pH were generally moderate, ranging from 7.1 at the Doane Creek reference site to 8.4 at Escondido Creek in Elfin Forest. Dissolved oxygen levels ranged from 3.77 mg/L at Tecolote Creek in Tecolote Natural Park to 12.33 mg/L at Santa Margarita River on Camp Pendleton. Water temperatures throughout the study region ranged from 7.7 °C at the Doane Creek reference site to 23.7 °C at Carroll Canyon Creek at Highway 805. The Doane Creek site was several degrees cooler than any other site. Specific conductance was highest at Tecolote Creek with a value of 7.992 mS/cm. and lowest at Doane Creek with a value of 0.363 ms/cm. San Diego River in Mission Trails Park and Chollas Creek-Federal Blvd. were also quite high, with values of 6.018 and 4.635 mS/cm, respectively. Chlorophyll values were generally low to moderate, with the exception of San Luis Rey River at Benet Road, which had a relative chlorophyll level of 22.2 mg/l. This may have been due to the lack of flowing water at the time of sampling. May 2005. Total physical habitat quality scores ranged from 79 at Escondido Creek at Harmony Grove Bridge to 181 at San Diego River in Mission Trails Park (Appendix B.6-2). Water quality data is presented in Appendix B.7-2. Values of pH were all quite moderate, ranging from 7.1 at Tijuana River at Dairy Mart Road to 8.4 at the Santa Margarita and Escondido Creek Sites. Dissolved oxygen values were moderate to high (note: three sites sampled on the same day had DO readings above 18 mg/L, and it is suspected that the meter was not properly calibrated). Water temperatures were more variable than in past surveys, ranging from 10.7°C at Doane Creek to 29.7°C at Escondido Creek at Harmony Grove Bridge. As in the October survey, specific conductance was highest at Tecolote Creek with a value of 3.594 ms/cm, and was nearly as high at Sweetwater River at Highway 94. Overall, however, specific conductance at most sites in the County were lower in May 2005 than in past surveys, possibly due to higher flow rates after the heavy rainfall of the 2004-2005 wet season. 13.4.1.3 Index of Biotic Integrity The California Department of Fish & Game (CDFG) Aquatic Bioassessment Laboratory developed a Southern California Index of Biotic Integrity (IBI) applicable to a region including San Diego County. The IBI was accepted for publication in the peer-reviewed journal Environmental Management in 2004 (Ode, et al 2005). The IBI is a multimetric index based on the cumulative value of seven biological metrics (Table 13-11), which provides a quality rating to a community of benthic macroinvertebrates. These 7 metrics were selected from 61 candidate metrics based on responsiveness to disturbance and lack of correlation to other metrics (to avoid redundancy). In developing the IBI, analysis included data sets from a variety of studies, most of which used protocols that processed 500 organisms rather than the 900 organisms identified under the California Stream Bioassessment Procedure (CSBP). To calculate the IBI for CSBP samples in this report, the 900 organism samples were reduced to 500 organisms by random elimination of taxa. This random elimination step was performed 10 times and the mean metric value obtained was used to determine the IBI score for each metric. Each metric value is scored from 0 to 10 based on the range of macroinvertebrate community conditions in the region, with higher scores indicating higher quality conditions. The scores were summed and the total index score was categorized into qualitative ratings of Very Good, Good, Fair, Poor, and Very Poor. CDFG considers the boundary between Fair and Poor (IBI score of 26) as the threshold for impairment. The IBI is quite accurate at broadly identifying impairment, but it must be noted that small differences in IBI scores are not significant and may be due to natural biological variability within a stream reach. Ode, et al determined that the minimum detectable difference between scores is about 9 points (on a 0-70 point scale), thus two site scores must be at least 9 points apart from one another to determine if one is of higher quality than the other. It may also be noted that lower elevation reference sites in San Diego County rarely, if ever, score in the Very Good range, and are usually in the Fair to Good range. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-50 Table 13-11. Index of Biotic Integrity Scoring Ranges. Metric Score Number Coleoptera Taxa Number EPT Taxa Number Predator Taxa Percent CF+CG Individuals Percent Intolerant Individuals Percent Non-Insect Taxa Percent Tolerant Taxa All Sites Region 6 Region 8 All Sites Region 6 Region 8 Region 6 Region 8 All Sites All Sites 10 >5 >17 >18 >12 0-59 0-39 25-100 42-100 0-8 0-4 9 16-17 17-18 12 60-63 40-46 23-24 37-41 9-12 5-8 8 5 15 16 11 64-67 47-52 21-22 32-36 13-17 9-12 7 4 13-14 14-15 10 68-71 53-58 19-20 27-31 18-21 13-16 6 11-12 13 9 72-75 59-64 16-18 23-26 22-25 17-19 5 3 9-10 11-12 8 76-80 65-70 13-15 19-22 26-29 20-22 4 2 7-8 10 7 81-84 71-76 10-12 14-18 30-34 23-25 3 5-6 8-9 6 85-88 77-82 7-9 10-13 35-38 26-29 2 1 4 7 5 89-92 83-88 4-6 6-9 39-42 30-33 1 2-3 5-6 4 93-96 89-94 1-3 2-5 43-46 34-37 0 0 0-1 0-4 0-3 97-100 95-100 0 0-1 47-100 38-100 Very Poor: 0-13; Poor: 14-26; Fair: 27-40; Good: 41-55; Very Good: 56-70 The investigators in this study have noticed that in rare circumstances individual IBI metrics may give a non-representative score. This generally occurs when the abundance of a site is very low, or when a single taxon dominates the community. Therefore, detailed analysis of the community composition is also necessary to determine if the IBI score is truly representative of the condition of a site. Total IBI scores with proportional metric compositions are shown in Figure 13-23 (October 2004) and 13-24 (May 2005). A complete list of the IBI parameter values and scores for each monitoring reach are listed in Appendix B.8. October 2004. IBI scores of the monitoring reaches ranged from 1 at Sweetwater River at Bonita Road to 59 at the Doane Creek reference site (Figure 13-23, Appendix B.8-1). Ten of the sites were rated Very Poor and 11 of the sites were rated Poor. The reference sites were rated Good and Very Good. The highest rated urban influenced sites were Green Valley Creek at West Bernardo Road and Rose Creek near Highway 52. In previous reports, scatterplot analysis of the relationship between IBI scores and physical habitat quality have shown a consistently low correlation coefficient, indicating that IBI scores are not a result of physical habitat quality differences, but are likely more driven by water quality. In the October 2003 survey, the highest rated urban influenced site, Santa Margarita River-Camp Pendleton, had an in-stream physical habitat that was dominated by unconsolidated sand, which is considered a poor substrate for macroinvertebrate colonization (MEC-Weston 2005). Contrastingly, sites such as San Diego River-1 and Escondido Creek-Harmony Grove Bridge had very good riffle characteristics (strong current, complex cobble/boulder substrates, native riparian canopy) yet were among the lowest scoring sites in the region. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-51 Index Biotic Integrity Scores for San Diego Bioassessment Sites. October 2004. 0 10 20 30 40 50 60 70 REF-DCREF-DLC3REF-SC2GVC-WBMB-RCSDR-MTSMR-WGRTC-TCNPCCC-805CC-FBBVR-CBESC-EFSMC-LCCCSMR-CPAHC-MRSD-DDHSLRR-BRLPC-CCRAHC-ECRESC-HRBSDR-1CC-CSLRR-MRSR-WSStationIBI ScoreNumber of EPT Taxa% Intolerant IndividualsNumber of Predator TaxaNumber of Coleoptera Taxa% Tolerant Taxa% Non-Insect Taxa% Collector-Filterers and Collector-Gatherers PoorVeryPoorFairGoodVery Good Figure 13-23. Index of Biotic Integrity Scores for San Diego County Bioassessment Sites. October 2004. May 2005. IBI scores of the monitoring reaches ranged from 1 at San Luis Rey River at Benet Road to 56 at the Doane Creek reference site (Figure 13-24, Appendix B.8-2). Seventeen of the sites were rated Very Poor and five of the sites were rated Poor, including the Sandia Creek reference site. The other two reference sites were rated Fair and Very Good. The Santa Margarita River site on Camp Pendleton was the highest scoring urban influenced site, with an IBI score of 24. As discussed in section 4.3 of this report, the Tijuana River site at Dairy Mart Road was one of the highest rated urban sites, but this rating is much higher than the benthic community should indicate. Comparing IBI scores to physical habitat conditions again indicated that many sites show little correlation between riffle quality and macroinvertebrate community quality. In the May 2005 survey, this was most evident at Tecolote Creek in Tecolote Canyon Natural Park, San Diego River near Morena Blvd., Green Valley Creek at West Bernardo Drive, and San Diego River in Mission Trails Park, which had good riffles and low IBI scores. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-52 Index Biotic Integrity Scores for San Diego Bioassessment Sites. May 2005. 0 10 20 30 40 50 60 70 REF-DCREF-WCREF-SC2SMR-CPSD-DDHSMR-WGRTJ-DMAHC-ECRESC-EFCC-FBMB-RCCCC-805LPC-CCRESC-HRBSLRR-MRSR-94SDR-MTAHC-MRGVC-WBSR-WSCC-CSDR-1TC-TCNPSLRR-BRStationIBI ScoreNumber of EPT Taxa% Intolerant IndividualsNumber of Predator TaxaNumber of Coleoptera Taxa% Tolerant Taxa% Non-Insect Taxa% Collector-Filterers and Collector-Gatherers PoorVeryPoorFairGoodVery Good Figure 13-24. Index of Biotic Integrity Scores for San Diego County Bioassessment Sites. May 2005. 13.4.1.4 Seasonal and Annual Trend Analysis Seasonal variability of the monitoring sites has shown some consistent patterns since the beginning of the San Diego County program in 2001. Index of biotic integrity scores were usually lower in the May surveys than in the October surveys. An analysis of variance (ANOVA) performed on the average regional IBI values indicated that there was a statistically significant difference between May and October scores. Figure 13-25 shows the average seasonal IBI scores by watershed, plus the average IBI score of all urban influenced San Diego County monitoring sites (reference sites were not included in this analysis). This figure clearly shows the up and down seasonal pattern of IBI results. Several observations have been made that provide likely explanations for this trend. One of the most obvious, observable differences in habitat conditions between spring and fall surveys is the growth of filamentous algae (usually Cladophora sp.) which occurs in the spring. The amount of algae varies considerably from site to site, and is probably related to nutrient loading and canopy cover in each stream. Sites with very heavy growths of algae tend to have had lower quality macroinvertebrate communities than when they are sampled without the algae present. Organisms that normally cling to rocky substrates appear to be especially impacted due to a reduced amount of suitable surface area for colonization. Filamentous algae naturally die off over the summer, and by the October surveys, the rocky substrates are re-colonized by insects, most noticeably Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-53 by Hydropsychid caddisflies. Sites that are particularly impacted by algae in the spring include Santa Margarita at Willow Glen Road, Escondido Creek in Elfin Forest, San Dieguito River on Del Dios Highway, San Marcos Creek above La Costa Country Club, and Rose Creek near Highway 52. 0 5 10 15 20 25 30 35 May-01 Oct-01 May-02 Oct-02 May-03 Oct-03 May-04 Oct-04 May-05IBI ScoreSanta Margarita San Luis Rey Carlsbad San Dieguito Creek Los Penasquitos Creek Mission Bay San Diego River San Diego Bay Tijuana River County Average Figure 13-25. Index of biotic integrity trends for San Diego County watersheds. May 2001 – May 2005. Seasonal variation in the benthic community composition also affects the IBI scores. May surveys generally have a higher percentage of collector filterers and collector gatherers, mostly consisting of Simulium, Amphipods, Ostracods, Chironomids, and Baetid mayflies (Appendix B.5-1, B.5-2). These animals feed on fine particulate organic matter, which is greatly increased by urban runoff. Over the summer, the abundance of these taxa decreases, while the abundance of predators increases, raising the score for the percent collector filterers plus collector gatherers IBI metric. Most notably, between May and October, many of the urban affected streams see substantial increases in the damselfly, Argia, a predatory, impairment tolerant insect. The county-wide total for Argia was 745 in October, and 41 in May (Appendix B.3-1, B.3-2). This trend was particularly evident at Agua Hedionda Creek at Melrose Drive, San Diego River in Mission Trails Park, and Tecolote Creek. In previous years surveys, two other aspects of the macroinvertebrate community that undergo seasonal trends are a greater percent tolerant taxa and a greater percent of non-insect taxa in the May surveys. Increases in both of these metrics will decrease the IBI score of the site. These trends, however, were not evident in the 2004-2005 survey year. In fact, the percent tolerant taxa decreased between October and May at every site in the county except Sweetwater River at Bonita Road. This may have been due to Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-54 the heavier than usual flows at the sites through the spring of 2005, since the most abundant of the tolerant taxa include amphipods, ostracods, and molluscs, all of which are characteristic of slow current habitats. Analysis of the multi-year trends of IBI scores did not show a significant upward or downward shift in macroinvertebrate community quality (Figure 13-25). Overall average IBI scores for the region in May 2001 were quite similar to the scores for May 2005, which were about one point higher than 2001. The intermediary surveys have indicated that some years or seasons produce better conditions for macroinvertebrates. May 2002 had the lowest overall IBI scores for a spring survey, and October 2004 had the lowest overall IBI scores for a fall survey, although the October 2004 IBI scores were quite similar to other fall surveys. Figure 13-26 is a whisker-box plot of Index of Biotic Integrity scores of all of the monitoring sites from May 2001 through May 2005. The sites are listed by watershed, from north to south. The whisker-box plot vertical line begins at the minimum value and ends at the maximum. A median value of the data is represented by a horizontal line, and the mean IBI score is represented by a circle. The median value is the value equidistant from the first score and the last score. Given sufficient data points, a whisker-box plot can differentiate four quartiles of the data. The red shaded box is the bounds of the second and third quartiles. This means 25% of the IBI values fall below the box and 25% are above the box. Figure 13-26. Whisker box plot of all San Diego County bioassessment monitoring sites, May 2001-May 2005. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-55 Figure 13-26 shows the overall variation of IBI scores of each monitoring site through the duration of the study to date. Many of the sites had a five to ten point range in IBI scores, although variability has been as much as 21 points in the case of San Luis Rey River at Mission Road. Other sites that have shown high variability in IBI scores include both of the Agua Hedionda Creek sites, Green Valley Creek, Carroll Canyon Creek, and Tecolote Creek. None of the sites, however, have ranged across two rating categories (e.g., from Very Poor to Fair). Overall variability at the reference sites has been similar to, or slightly greater than, the urban affected sites. If seasonal trends in IBI scores are considered, the overall variability is greatly diminished. In other words, if only the May surveys are considered, there is much less variability from year to year. 13.4.2 Summary and Conclusions A total of 27 different stream monitoring reaches were assessed in San Diego County in the surveys of October 2004 and May 2005. Four of these sites were considered to represent reference conditions. A total of 49 different monitoring reaches have been sampled since May 2001. Taxonomic identification of samples collected in October 2004 produced 110 taxa from a total of 18,460 individuals. The May 2005 samples produced 91 taxa from 21,534 individuals. The most abundant organisms in October 2004 in the study region were Simulium (Diptera: Simuliidae), non-biting midges (Diptera: Chironomidae), Hyalella (Amphipoda: Hyalellidae) and Ostracods (Ostracoda). The most abundant organisms in May 2005 in the study region were Simulium (Diptera: Simuliidae), Baetis (Epemeroptera: Baetidae), and non-biting midges (Diptera: Chironomidae). The majority of organisms from the urban affected sites were moderately or highly tolerant to stream impairments. Organisms highly intolerant to impairments were encountered infrequently at the urban affected sites, but their presence even in low numbers is significant. Non-reference sites that supported highly intolerant organisms included San Dieguito River-Del Dios Highway and Santa Margarita River- Willow Glen Road. The Index of Biotic Integrity ratings of the monitoring sites ranged from Very Good to Very Poor in October 2004 and May 2005. IBI scores for the reference sites were always higher than the scores for the urban influenced sites, although REF-SC2 was one point higher than the highest non-reference site in the May 2005 survey. The May 2005 survey produced consistently lower IBI scores across the entire region than in the October 2004 survey. Comparison of IBI scores with the in-stream physical habitat quality of the monitoring reaches indicated a poor correlation between habitat quality and benthic macroinvertebrate community quality. Of all of the watersheds in San Diego County, the Santa Margarita River watershed had the least impaired benthic macroinvertebrate communities. The remaining watersheds have substantially greater amounts of urbanization, and the IBI results generally indicate that greater water quality impairment occurs in the lower portions of the watersheds as the impacts of urban runoff become cumulative. After 4½ years of bioassessment surveys, the most significant observation is that the macroinvertebrate community quality has not shown any trend towards degradation or improvement. IBI scores for most of the San Diego sites were similar in May 2005 to May 2001. Individual seasons or years have produced better conditions for the macroinvertebrates, and many of the monitoring sites have shown a parallel response to the variability of the conditions. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-56 13.5 Ambient Bay and Lagoon Monitoring Introduction The overall goal of the Ambient Bay and Lagoon Monitoring (ABLM) Program is to develop and implement an environmental study to monitor the impact of urban runoff on the major coastal embayments in San Diego County and assess the overall health of these receiving waters. The objectives, approach, validation of the approach, materials, and methods are presented in Section 3.3. In this section, the results from samples collected during the summer of 2004 are presented. It is organized into two main sub-sections: Phase I-Contaminant Targeting: Discusses the Total Organic Carbon (TOC) and grain size results from the nine samples collected within each of the 12 coastal embayments; and Phase II-Sediment Assessment: Discusses the sediment chemistry, toxicity, and benthic infauna results from each of the embayments. The purpose of this section is to provide an overview of the results from samples collected during the summer of 2004, which provides a means of comparing sediment chemistry, toxicity, and benthic infauna results across the 12 coastal embayments in San Diego County. Assessments in subsequent years of the program will include an analysis of each year of the study, which will allow for an assessment of trends within the coastal embayments over time. More detailed site-specific assessments for each embayment are provided in Sections 4 through 12. Phase I – Contaminant Targeting In the summer of 2004 12 coastal embayments in San Diego County were assessed in the ABLM program (Table 13-12, Figure 13-27). Table 13-12. Coastal embayments monitored in the summer of 2004 for the Ambient Bay and Lagoon Monitoring Program. Name of Coastal Embayment Site Designation Watershed Management Area Major Freshwater Tributary Santa Margarita River Estuary SME Santa Margarita River Santa Margarita River Oceanside Harbor OH Santa Margarita River None San Luis Rey River Estuary SLE San Luis Rey River San Luis Rey River Buena Vista Lagoon BVL Carlsbad Buena Vista Creek Agua Hedionda Lagoon AHL Carlsbad Agua Hedionda Creek Batiquitos Lagoon BL Carlsbad San Marcos Creek San Elijo Lagoon SEL Carlsbad Escondido Creek San Dieguito Lagoon SDL San Dieguito San Dieguito River Los Peñasquitos Lagoon LPL Peñasquitos Los Peñasquitos Creek Mission Bay (includes Rose and Tecolote Creek outfalls) MB Mission Bay Rose Creek and Tecolote Creek Sweetwater River Estuary SRE San Diego Bay Sweetwater River Tijuana River Estuary TRE Tijuana River Tijuana River Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-57 The embayments are shown graphically in Figure 13-27. Descriptions for each of the sites are presented in Sections 4 through 12 of this report. Figure 13-27. Map of coastal embayments sampled in the summer of 2004 for the Ambient Bay and Lagoon Monitoring Program. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-58 TOC and Grain Size Results As discussed in Section 3.3.3, a stratified random approach was used to select sampling sites within each embayment. Each embayment was stratified into three strata: 1. Stratum 1 - an outer stratum located nearest the ocean; 2. Stratum 2 - a middle stratum, centered upon the lagoon; and 3. Stratum 3 - an inner stratum, located nearest the major watershed input source. Each of these three strata was further divided into three areas roughly along the longitudinal axis of the embayment: right bank (looking downstream), center, and left bank. Thus, nine strata were delineated and sampled in each embayment. The TOC and grain size results from the Phase I sampling in each of the nine strata are presented in Table 13-13. After sediment samples from the nine sites in each of the twelve embayments were analyzed, the sites in each embayment were ranked based on the percentage of fine grained sediments and TOC levels. The sites with the smallest grain size (i.e., the highest percentage of fine-grained sediments) received the highest rank for grain size and the sites with the highest TOC content received the highest rank for TOC. The ranks for grain size and TOC at each site were then summed to produce an overall rank for that site. The three sites in each embayment with the highest ranks were assessed in Phase II of the program. In the case of a tie in the summed ranks, the site with the higher fines rank was selected for Phase II assessment. The results of the ranking from Phase I are presented in Table 13-13. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-59 Table 13-13. Ambient Bay and Lagoon Phase I TOC and grain size results. Embayment Site Number Fines (%)* TOC (%) Selected for Phase II Embayment Site Number Fines (%)* TOC (%) Selected for Phase II SME 1L-2 3.77 0.07 BL 1L-1 16.57 0.57 SME 1M-1 2.24 0.05 BL 1M-1 22.96 0.55 SME 1R-1 4.43 0.10 Yes BL 1R-1 29.53 0.79 SME 2L-1 2.62 0.09 BL 2L-1 49.90 0.80 SME 2M-1 13.37 0.28 Yes BL 2M-1 24.84 0.99 SME 2R-2 13.73 0.25 Yes BL 2R-1 97.05 1.91 Yes SME 3L-1 3.24 0.08 BL 3L-1 99.12 1.32 Yes SME 3M-1 2.97 0.07 BL 3M-1 92.54 1.46 Yes SME 3R-3 4.31 0.17 BL 3R-1 91.92 1.60 OH 1L-1 1.72 0.06 SEL 1L-1 20.20 0.62 OH 1M-1 12.69 0.23 SEL 1M-1 19.67 0.66 OH 1R-1 20.66 0.38 SEL 1R-1 1.12 0.05 OH 2L-1 5.25 0.24 SEL 2L-1 60.62 1.64 Yes OH 2M-1 6.80 0.12 SEL 2M-1 51.92 1.26 OH 2R-2 10.71 0.11 SEL 2R-1 45.67 1.73 OH 3L-1 62.91 1.07 Yes SEL 3L-2 47.95 2.84 Yes OH 3M-1 88.96 1.29 Yes SEL 3M-1 43.15 1.53 OH 3R-1 63.45 0.77 Yes SEL 3R-1 56.88 3.36 Yes SLE 1L-1 17.29 0.31 SDL 1L-1 39.00 1.27 SLE 1M-1 15.50 0.38 SDL 1M-1 23.53 0.63 SLE 1R-1 17.84 0.46 SDL 1R-1 1.16 0.05 SLE 2L-1 43.34 1.06 Yes SDL 2L-1 31.93 1.23 SLE 2M-1 39.36 1.36 Yes SDL 2M-1 65.24 2.03 Yes SLE 2R-1 30.45 0.79 SDL 2R-1 65.60 1.43 Yes SLE 3L-1 59.25 1.07 Yes SDL 3L-1 42.21 1.27 SLE 3M-1 39.05 0.90 SDL 3M-1 22.99 0.36 SLE 3R-1 28.86 0.95 SDL 3R-1 62.94 1.85 Yes BVL 1L-1 24.50 2.43 LPL 1L-1 5.88 0.19 BVL 1M-1 93.83 7.75 Yes LPL 1M-1 7.75 0.17 BVL 1R-1 93.75 5.98 Yes LPL 1R-2 8.46 0.24 BVL 2L-1 97.20 2.98 LPL 2L-4 77.78 1.51 BVL 2M-1 93.25 3.57 LPL 2M-2 79.86 1.52 BVL 2R-1 62.35 6.40 LPL 2R-1 88.33 2.41 Yes BVL 3L-1 95.29 5.29 Yes LPL 3L-1 72.52 1.90 BVL 3M-1 93.42 5.60 LPL 3M-2 80.77 1.72 Yes BVL 3R-1 91.09 6.73 LPL 3R-2 80.22 1.84 Yes AHL 1L-1 3.09 0.43 MB 1L-1 82.82 2.38 Yes AHL 1M-1 11.10 0.23 MB 1M-1 7.98 0.55 AHL 1R-1 5.36 0.14 MB 1R-1 65.07 2.17 AHL 2L-2 87.37 1.39 Yes MB 2L-1 33.65 0.96 AHL 2M-2 38.60 0.67 MB 2M-1 4.47 0.25 AHL 2R-1 23.85 0.45 MB 2R-1 14.93 0.59 AHL 3L-1 94.78 1.50 Yes MB 3L-1 92.58 2.52 Yes AHL 3M-1 12.08 0.38 MB 3M-1 85.27 1.72 AHL 3R-1 83.92 1.12 Yes MB 3R-1 81.43 2.49 Yes SRE 1L-1 58.02 0.64 TRE 1L-2 27.08 0.57 Yes SRE 1M-1 81.05 1.17 Yes TRE 1M-1 1.87 0.10 SRE 1R-1 52.80 0.73 TRE 1R-2 12.03 0.39 SRE 2L-1 82.42 1.48 Yes TRE 2L-1 86.57 1.28 Yes SRE 2M-2 76.52 1.04 TRE 2M-1 4.77 0.09 SRE 2R-1 41.57 1.05 TRE 2R-1 16.20 0.40 SRE 3L-1 38.34 1.29 TRE 3L-1 17.55 1.05 SRE 3M-1 17.04 0.57 TRE 3M-1 33.82 0.67 Yes SRE 3R-1 52.48 1.30 Yes TRE 3R-1 18.07 0.51 * The grain size results are presented as percent fines (silt and clay fractions), which was used for site rankings. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-60 Sediment samples from the Phase I assessment were collected from the twelve coastal embayments between June 2, 2004 and June 15, 2004. A summary of the percentage of fine- grained sediment and the sediment’s TOC content for the 12 embayments monitored in the summer of 2004 ABLM Program is presented in Figure 13-28. The mean percentage of fine- grained sediments (nine sites per embayment) was fairly similar among the 12 embayments. However, sediments at two embayments appeared to be distinctly different from the others. Santa Margarita River Estuary (SME) had a much smaller proportion of fine-grained sediments (i.e., a larger median grain size) than any of the other embayments in San Diego County. Sediments at Santa Margarita River Estuary also had a much lower mean TOC content than the other embayments. In contrast, sediments at Buena Vista Lagoon (BVL) had a distinctly higher proportion of fine-grained sediments than the other embayments in the County and a much higher TOC content. Typically, sites that had high levels of fine-grained sediments also had high levels of TOC. Figure 13-29 shows the relationship between fine grain size and TOC content for all of the 108 sites (9 sites at each of 12 embayments) monitored in the summer of 2004 ABLM Program. The results for each embayment and the subsequent ranking of Phase II sites are presented in the following section. In general, there was a fairly good relationship between percent TOC and percent fines (R2=0.46). Phase II – Sediment Assessment The results of Phase I were used to identify the three sites in each embayment that contained the highest TOC levels and smallest grain size of the nine sites assessed. Sediments at these three sites were re-sampled in July 2004 and analyzed for three main parameters: chemistry, toxicity, and benthic infauna. The three samples collected from each embayment for sediment chemistry and toxicity were composited so that a single sample was analyzed for these parameters for each embayment. For benthic infauna, each of the three sites per embayment was analyzed separately. The results for each parameter are presented below. Mean percent fines and TOC content of sediment at ABLM Program embayments 0.00 20.00 40.00 60.00 80.00 100.00 SMEOHSLEBVLAHLBLSELSDLLPLMBSRETREEmbaymentFines (%)0.00 1.00 2.00 3.00 4.00 5.00 6.00 TOC (%)Fines % TOC % Figure 13-28. Mean percent fines and TOC content of sediment at ABLM Program embayments. Relationship between percent fines and TOC TOC = 0.0304Fines - 0.0156 R2 = 0.458 0 2 4 6 8 10 0 20406080100 Fines (%)TOC (%)Figure 13-29. Relationship between percent fines and TOC content. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-61 Sediment Chemistry Samples collected for sediment chemistry were analyzed for four basic constituents: metals, PCBs, PAHs, and pesticides. As discussed in Section 3.3.5, the results were compared to effects-based sediment quality guidelines for evaluating the potential for constituents to cause adverse biological effects. The guidelines were based on empirical analyses of numerous studies and were intended to provide informal (non-regulatory) effects-based benchmarks of sediment chemistry data (Long et al. 1998). Two effects categories have been identified: ERL – Effects Range Low: concentrations below which adverse biological effects are rarely observed; and ERM – Effects Range Medium: concentrations above which adverse biological effects are more frequently, though not always, observed. In addition, ERM values were used to calculate a mean ERM Quotient (ERM-Q). The ERM-Q was calculated by dividing the concentration of each COC by its ERM value. The mean ERM-Q for each embayment was then calculated by summing the ERM-Qs for each COC and then dividing by the total number of ERM-Qs assessed. ERM-Qs were not calculated for COC below the detection limit and thus were not used in the generation of the mean ERM-Q. The mean ERM-Q represents the cumulative sediment chemistry effect for each embayment based on the screening values. COC concentrations for each embayment from samples collected in the summer of 2004 and corresponding ERL and ERM values are presented in Table 13-14. Metals A total of nine metals were assessed in sediment samples collected in 2004 (Table 13-14). All of these were detected in at least one embayment assessed in the ABLM Program. Arsenic, chromium, copper, lead, nickel, and zinc were found above the detection limit at all of the 12 embayments assessed. In contrast, selenium was found above the detection limit only at Oceanside Harbor, Los Peñasquitos Lagoon, and Mission Bay. Cadmium was found above the detection limit at Buena Vista Lagoon, San Elijo Lagoon, San Dieguito, and the Tijuana Estuary. In general, concentrations of all metals in sediments were low among the 12 embayments (Table 13-14). When compared to the ERL values, concentrations of metals exceeded the ERL in only twelve of the 108 analyses conducted (12 embayments times nine analyses). ERL values of only five metals were exceeded. The ERL quotient for arsenic was exceeded most frequently (four embayments), followed by copper and zinc (three embayments), and finally lead and nickel (one embayment each). In most cases, the ERL value was exceeded only slightly, suggesting minimal impacts to the biota from individual COC. One possible exception to this was the ERL value for copper (34 mg/kg), which was exceeded nearly five fold at Mission Bay (148 mg/kg) and nearly four times at Oceanside Harbor (116 mg/kg). However, none of the COC exceeded the ERM values and in all cases were well below this threshold. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-62 Table 13-14. Concentration of COCs in sediment for each coastal embayment compared to sediment quality guidelines (ERL and ERM). ANALYTE ERL ERM SME OH SLR BVL AHL BL SEL SDL LPL MB SRE TRE METALS (mg/kg) Antimony nd nd nd nd nd nd nd nd nd nd nd nd nd ndArsenic 8.2 70 1.67 8.15 2.25 7.388.28 9.193.52 3.21 9.39 12.74.67 5.36Cadmium 1.2 9.6 nd nd nd 0.646 nd nd 0.33 1.33 nd nd nd 0.374Chromium 81 370 13.2 42.2 37.4 35.9 33.230.4 15.3 26.1 21.8 43.2 24.5 28.4Copper 34 270 6.45 116 17.643.523.1 18.6 17.8 16.5 14.4 14833.1 18Lead 46.7 218 5.13 19.6 4.1 32.513.7 15.7 12.7 7.65 17.7 50.422.9 19.9Nickel 20.9 51.6 4.92 15 21.514.1 10.6 10.6 5.89 8.19 8.1 12.9 8.57 11.1Selenium nd nd nd 1.63 nd nd nd nd nd nd 1.98 1.96 nd ndZinc 150 410 37.2 177 39.818070.2 76.2 51.5 63.8 75.6 191129 98.4PCBs (ug/kg) Aroclor 1016 nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Aroclor 1221 nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Aroclor 1232 nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Aroclor 1242 nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Aroclor 1248 nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Aroclor 1254 nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Aroclor 1260 nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1PAHs (ug/kg) Acenaphthene 16 500 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Acenaphthylene 44 640 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Anthracene 85.3 1100 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Benzo (a) anthracene 261 1600 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Benzo (a) pyrene 430 1600 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Benzo (b) fluoranthene nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Benzo (g,h,i) perylene nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Benzo (k) fluoranthene nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Chrysene 384 2800 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Dibenz (a,h) anthracene 63.4 260 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Fluoranthene 600 5100 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Fluorene 19 540 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Indeno (1,2,3-cd) pyrene nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Naphthalene 160 2100 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Phenanthrene nd nd <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Pyrene 665 2600 <15.4 <20.0 <17.9 <45.7 <24.0 <31.4 <29.0 <23.0 <28.0 <31.5 <20.4 <24.1Pesticides (mg/kg) Diazinon nd nd <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01Chlorpyrifos nd nd <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 Mean ERM-Q 0.0488 0.245 0.1218 0.204 0.1222 0.124 0.0759 0.088 0.111 0.299 0.1402 0.128Bold numbers are above the ERL Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-63 PCBs PCBs were not found above the detection limit at any site assessed in the ABLM program (Table 13-14). PAHs PAHs were not found above the detection limit at any site assessed in the ABLM program (Table13-14). Pesticides Two pesticides were assessed in the ABLM Program: Diazinon and Chlorpyrifos (Table 13-14). Neither was found above the detection limit in sediments from any of the coastal embayments assessed. Mean ERM quotients As discussed above, the ERM-Qs represent the cumulative effect to the biota from all of the COC assessed for which ERMs are available. ERM values were available for 18 of the constituents assessed in the ABLM Program. The mean ERM-Qs based on these ERMs for all 12 embayments are presented in Table 13-14 and Figure 13-30. Overall, the mean ERM-Qs were low for all of the 12 coastal embayments, reflecting the low concentrations of metals, PAHs, PCBs and pesticides (Table 13-14). The lowest ERM quotients were found at the Santa Margarita River Estuary, San Elijo Lagoon, and San Dieguito Lagoon. All of these embayments had ERM quotients below the threshold value of 0.10 presented by Long et al. (1998). The probability of a highly toxic response of organisms exposed to sediments with mean ERM-Qs below this threshold is less than 12%. Mean ERM-Qs for the remainder of the embayments were greater than 0.10. The embayments with the highest ERM-Qs were Mission Bay, Oceanside Harbor, and Buena Vista Lagoon with values of 0.299, 0.245, and 0.204 respectively. In Mission Bay, the high mean ERM-Q value was primarily a result of high concentrations of arsenic, copper, lead, and zinc. In both Oceanside Harbor and Buena Vista Lagoon, high mean ERM-Q values resulted from high concentrations of copper and zinc. The probability of highly toxic responses increases to 32% in sediments with mean ERM-Q values between 0.11 and 1.0 (Long et al. 1998). Even the most contaminated embayments in the 2004 ABLM Program (Mission Bay and Oceanside Harbor) had mean ERM-Qs at the low end of this range. In addition, it is important to remember that the results of Phase I were used to target areas in each embayment where contaminants were most likely to be found (i.e., those areas with the smallest grain Mean ERM quotients by embayment. Bars below the red line have a low probability of effects on the biota (Long et al. 1998) 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35SMEOHSLRBVLAHLBLSELSDLLPLMBSRETRE EmbaymentMean ERMqFigure 13-30. Mean ERM quotients by embayment. Bars below the red line have a low probability of effects on biota (from Long et al. 1998). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-64 size and highest TOC content). Thus, the results of the chemical analyses of the sediments likely represent a worst-case scenario for each of the embayments. COC Association with TOC and Grain Size The validity of the experimental design for the ABLM Program was centered on the assumption that there was a strong positive relationship between COC, high TOC content, and small grain size. Prior to the first sampling season, data from another embayment in southern California (Newport Bay) was used to test the strength of the correlation between these constituents. In that assessment, there was a statistical relationship between contaminants in the sediment, high TOC content, and small grain size. The data from the coastal embayments in San Diego County assessed during the 2004 ABLM Program also indicate that there is a good relationship between COC, high TOC content, and small grain size. The data are depicted graphically in Figure 13-31, where mean ERM-Q values for each embayment are compared to the corresponding TOC content (Figure 13-31A) and grain size (Figure 13-31B) from each embayment. All values presented are from analysis of composite samples (three sites per embayment) collected during the Phase II assessment. To assess the cumulative effects of grain size and TOC on sediment chemistry, the grain size and TOC results were ranked for each embayment. The ranks for TOC and grain size for each embayment were then summed to produce an overall combined rank for these two constituents. The combined grain size and TOC rank for each embayment was then compared to the corresponding mean ERM-Q rank for that embayment. The relationship is shown graphically in Figure 13-31C. The R² for the relationship between the mean ERM-Q rank and the summed rank for TOC and grain size was 0.27. This suggests that there is a relationship between COC, TOC content, and grain size and helps validate the approach utilized in the study design for the Program. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-65 Figure 13-31. Mean ERM-Q values for each embayment versus TOC (A), and grain size (B) and mean ERM-Q rank for each embayment versus the TOC and grain size summed rank (C). A) TOC vs ERM-Q R2 = 0.168 0 1 2 3 4 5 6 7 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 Mean ERM-QTOC (%)B) Fines vs ERM-Q R2 = 0.326 0 10 20 30 40 50 60 70 80 90 100 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 Mean ERM-QFines (%)C) TOC & Grain Size Rank vs ERM-Q Rank R2 = 0.272 0 5 10 15 20 25 02468101214 Mean ERM-Q RankTOC and Grain Size Rank Sum Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-66 Sediment Toxicity Sediment toxicity from composite samples from each of the embayments was tested using the marine amphipod Eohaustorius estuarius. The test animals were exposed to sediment in the presence of filtered seawater for ten days, percent survival was then recorded. A control test was conducted with the field samples using clean marine sediments. Each sediment type was run with five replicates and 20 animals per replicate (total of 100 animals tested per embayment). In addition, a reference toxicant (cadmium chloride) with a known concentration test was also run concurrently with the other tests to assess the sensitivity of the test organisms. The EC50 value for the reference toxicant was 5.21 mg/L, which was within two standard deviations (+ 2.53 mg/L) of the laboratory mean of 5.33 mg/L and within the normal range for this toxicant. The sediment toxicity results for each embayment are presented in Table 13-15. Percent survival refers to the mean survival among the five replicates for each embayment. Survival of the test organisms varied among the embayments, ranging from 98% at Buena Vista Lagoon to 66% at both Batiquitos and San Dieguito Lagoons. To assess the relative toxicity of the sediments, percent survival of the embayment sediments were compared to percent survival of the Control (99%) using Analysis of Variance (ANOVA). The mean survival of test organisms exposed to sediments from ten sites was not significantly different (p =0.05) from Control sediment survival: the Santa Margarita River Estuary, Oceanside Harbor, the San Luis Rey River Estuary, Buena Vista Lagoon, Agua Hedionda Lagoon, San Elijo Lagoon, Los Penasquitos Lagoon, Mission Bay, the Sweetwater River Estuary, and the Tijuana River Estuary. Mean survival of test organisms exposed to sediments from the other two sites assessed in the study was significantly different from control sediment survival. Batiquitos Lagoon and San Dieguito Lagoon had much lower survival rates than the other sites assessed, suggesting elevated sediment toxicity in these embayments. Table 13-15. Results of sediment toxicity tests for each embayment in the ABLM Program. Embayment Percent Survival Significantly different from Control Santa Margarita River Estuary 97% No Oceanside Harbor 86% No San Luis Rey River Estuary 92% No Buena Vista Lagoon 98% No Agua Hedionda Lagoon 85% No Batiquitos Lagoon 66% Yes San Elijo Lagoon 88% No San Dieguito Lagoon 66% Yes Los Peñasquitos Lagoon 96% No Mission Bay 81% No Sweetwater River Estuary 79% No Tijuana River Estuary 97% No Control 99% NA NA = not applicable Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-67 Benthic Infauna In order to assess the biological condition of the sediments in each embayment, benthic infaunal organisms from three grab samples per embayment were identified. A total of 197 taxa were identified among the 12 embayments (Table 13-16). These total number of taxa among the embayments was dominated by polychaetes (71 taxa), followed by crustaceans (48 taxa), mollusks (41 taxa), minor phyla (32 taxa), and echinoderms (5 taxa). A total of 19,264 organisms were collected and identified among the embayments in the summer of 2004. Polychaetes were the most abundant group (7,257 individuals), followed by mollusks (5,567 individuals) and crustaceans (4,426 individuals). Abundance of echinoderms (39 individuals) was relatively low. The five most abundant and most common taxa collected from all 12 coastal embayments are summarized in Table 13-17. Grandidierella japonica, a common, nonindigenous gammarid amphipod that is found in sandy intertidal and subtidal sediments (Chapman and Dorman 1975) was the most abundant taxon, accounting for 14.4 % of all the infaunal organisms collected in the summer of 2004. This taxon was also the most common as it was found in all of the 12 embayments in the ABLM study area. Barleeia sp., a genus of barley snail that is a very common intertidal gastropod found throughout southern California, was the second most abundant species collected, accounting for 13.7% of the total. Although abundant, this gastropod was only found in six of the 12 embayments. Oligochaete worms were also very common (found in nine of the 12 embayments), but were not particularly abundant (1% of total). Polydora nuchalis, a polychaete that often occurs in dense assemblages in intertidal lagoons, was also abundant at 7.8% of the total, but only found in seven embayments. Another polychaete, Capitella capitata, was found in seven of the embayments and made up 5.6% of the total infaunal community collected. A highly tolerant species, Capitella sp., often survive in the most adverse of habitats. Acteocina inculta, a nudibranch common to mudflats in bays and lagoons, was the fifth most abundant taxon, but was found in only seven of the embayments. Table 13-17. Summary of the most abundant and most common taxa collected at all 12 coastal embayments monitored in the ABLM Program. Most Abundant Taxa Most Common Taxa Taxon Percent of Total Taxon Number of Embayments Grandidierella japonica 14.43 Grandidierella japonica 12 Barleeia sp 13.69 Musculista senhousei 11 Polydora nuchalis 7.78 Oligochaeta 9 Capitella capitata 5.63 Mediomastus sp 9 Acteocina inculta 5.29 Lineidae 9 Table 13-16. Summary of major benthic infauna classifications collected from sediments in the 12 coastal embayments monitored in the ABLM Program. Major Taxon Total Number of Taxa Total Number of Individuals Polychaetes 71 7,257 Crustaceans 48 4,426 Molluscs 41 5,567 Minor Phyla 32 1,975 Echinoderms 5 39 TOTAL 197 19,264 Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-68 As described in the methods in Section 13.3.3, several infaunal indices were calculated to aid in the examination of the community structure in each embayment. These indices included taxa richness (number of species), taxa abundance, Shannon-Wiener diversity index, evenness, and dominance. The indices for each embayment are presented in Table 13-18 and discussed below. Table 13-18. Indices of community structure in Ambient Bay and Lagoon Monitoring Program from samples collected in the summer of 2004. Values represent the mean of three sites per embayment unless otherwise noted. Embayment Richness Abundance Shannon-Wiener Diversity Index Evenness Dominance SME 11.0 141 1.73 0.74 3.67 OH 40.7 339 2.80 0.76 9.67 SLR 8.0 417 1.17 0.59 2.00 BVL 5.0 55 0.66 0.40 1.33 AHL 22.7 362 1.60 0.56 4.00 BL 24.3 955 1.41 0.49 2.00 SEL 5.7 443 0.89 0.64 1.67 SDL 16.3 772 1.71 0.62 3.33 LPL 29.3 811 1.58 0.47 3.00 MB 43.3 853 2.62 0.70 7.00 SRE 37.7 947 2.32 0.64 5.00 TRE 22.3 328 1.82 0.60 3.33 Average taxa richness (i.e., average number of taxa identified per embayment) ranged from 5.0 to 43.3 taxa per embayment (Table 13-18). Taxa richness was lowest at Buena Vista Lagoon, the San Luis Rey Estuary, and San Elijo Lagoon (Figure 13-32). Taxa richness was highest at Mission Bay, followed by Oceanside Harbor and the Sweetwater River Estuary. Taxa richness among embayments 0.0 10.0 20.0 30.0 40.0 50.0 SMEOHSLEBVLAHLBLSELSDLLPLMBSRETREEmbaymentTaxa RichnessSeries1 Figure 13-32. Taxa Richness among embayments. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-69 Average taxa abundance (i.e., average number of animals collected per embayment) ranged from 55 to 955 animals per embayment (Table 13-18). As with taxa richness, abundance was lowest at Buena Vista Lagoon (Figure 13-33), followed by the Santa Margarita River Estuary, and the Tijuana River Estuary. Samples collected from Batiquitos Lagoon had the largest number of animals of any embayment in the study, followed by the San Luis Rey River Estuary, Mission Bay, and Los Peñasquitos Lagoon. The average Shannon Wiener Diversity Index ranged from 0.66 to 2.8 (Table 13-18). As with taxa richness and abundance, the lowest value for this index was calculated for samples collected from Buena Vista Lagoon (Figure 13-34). San Elijo Lagoon, the San Luis Rey River Estuary, and Batiquitos Lagoon also had lower than average Shannon Weiner Diversity indices. The highest values for this index were found at Oceanside Harbor, followed by Mission Bay, the Sweetwater River Estuary, and the Tijuana River Estuary. Taxa evenness compares the similarity of the population size of each of the taxa present and is thus a measure of the relative abundance of the taxa in the embayment. Average evenness values ranged from 0.40 to 0.76 (Table 13-18). The lowest evenness value was found at Buena Vista Lagoon (Figure 13-35). Aside from this embayment, there was not a lot of variability among embayments in the evenness value. Taxa Abundance among embayments 0 200 400 600 800 1000 1200 SME OH SLE BVL AHL BL SEL SDL LPL MB SRE TRE EmbaymentsTaxa AbundanceFigure 13-33. Taxa Abundance among embayments. Shannon Wiener Diversity Index among embayments 0.00 0.50 1.00 1.50 2.00 2.50 3.00 SME OH SLE BVL AHL BL SEL SDL LPL MB SRE TRE EmbaymentsShannon Wiener (H')Figure 13-34. Shannon Weiner Diversity Index among embayments. Taxa Evenness among embayments 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 SME OH SLE BVL AHL BL SEL SDL LPL MB SRE TRE EmbaymentEvenness Figure 13-35. Taxa Evenness among embayments. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-70 The dominance index measures the extent to which the abundance of one taxon dominates the infaunal composition for a given embayment. The higher the dominance value the greater the number of co- dominant species. The average Dominance Index ranged from 1.33 to 9.67 (Table 13-18). Dominance was lowest at Buena Vista Lagoon (1.33), San Elijo Lagoon (1.67), followed by the San Luis Rey River Estuary (2.00), and Batiquitos Lagoon (2.00) (Figure 13-36). The highest dominance index was found at Oceanside Harbor, followed by Mission Bay, the Sweetwater River Estuary, and Agua Hedionda Lagoon. Cluster analyses are performed to determine the degree of similarity between sites for a given parameter or set of parameters. They can be useful in assessing the characteristics of a site in relation to other sites based on the structure of the biological community. The results of the cluster analyses for the ABLM infaunal communities collected in the summer of 2004 have been combined into a two-way coincidence table (Figure 13-37). The size of the square in each cell of the table was determined by the abundance of the taxon at each embayment relative to the mean abundance of that taxon over all the embayments. Thus, larger squares represent greater relative abundance. The results of the cluster analysis indicate that there are three major embayment cluster groups: Embayment Group A contained Agua Hedionda Lagoon, Batiquitos Lagoon, Mission Bay, the Sweetwater River Estuary, and Oceanside Harbor. Cluster Group B contained only Buena Vista Lagoon. Embayment Group C contained Los Peñasquitos Lagoon, the Tijuana River Estuary, San Dieguito Lagoon, San Elijo Lagoon, the San Luis Rey River Estuary, and the Santa Margarita River Estuary. The embayments clustered together largely based on overall abundance, where the embayments in Embayment Group A had a much greater infaunal abundance than those in Groups B and C (Figure 13- 37). In addition, the embayments in Embayment Group A were characterized by species comprising Taxa Groups 1 and 2. Several taxa in Taxa Group 1 were more abundant in Group C embayments or found there exclusively. These taxa included the polychaete worms, Capitella capitata and Polydora nuchalis, the gammarid amphipod, Monocorophium insidiosium, and oligochaete worms (Oligochaeta). Embayment Group B was characterized by a single embayment: Buena Vista Lagoon. This embayment was marked by a very low diversity and abundance and was represented in the cluster analysis by only one species: Chironomidae, a group that includes black flies and midges whose larvae utilize freshwater environments. As discussed in Section 6.4.1, Buena Vista Lagoon was unique among the embayments because it is a freshwater lagoon and has been permanently cut off from tidal exchange. This explains the low diversity and abundance (of marine species) as well as the presence of freshwater organisms found in this embayment. Taxa Dominance among embayments 0.00 2.00 4.00 6.00 8.00 10.00 12.00 SMEOHSLEBVLAHLBLSELSDLLPLMBSRETREEmbaymentDominance Figure 13-36. Taxa Dominance among embayments. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-71 Figure 13-37. Results of cluster analyses for coastal embayments and benthic taxa relative abundance. Symbol size indicates station concentration (x) relative to the mean concentration for each measure:0 0< x 0.50.5< x 1.01.0< x 1.51.5< x 2.0 x > 2.0<<<<Distance between clustersEmbayment Cluster Group Species Cluster Group0.00.51.01.5401235 Agua HediondaBatiquitosMission BaySweetwaterOceanside HarborBuena VistaLos PenasquitosTijuanaSan DieguitoSan ElijoSan Luis ReySanta MargaritaEricthonius brasiliensisPodocopidHippolyte californiensisTethygenia opataCapitella capitata CmplxMonocorophium insidiosumTryonia imitatorTresus nuttalliOligochaetaGrandidierella japonicaPolydora nuchalisVenerupis phillipinariumSpiochaetopterus costarumPhoronidaTellina cadieniScolelepis sp SD1Protothaca spArgopecten circularisPrionospio lighti Oxyurostylis pacifica Boccardiella hamata Macoma nasuta Notomastus hemipodus Streblospio benedictiParanemertes californica Haminaea vesiculaPectinaria californiensisClevelandia ios Laevicardium substriatumSpiophanes duplex Cerithidea californica Tagelus subteres Lineidae Metasychis disparidentatusThracia spCossura sp AAphelochaeta sp SD5Monticellina crypticaEuchone limnicola Dorvillea (Schistomeringos) longicornis Mayerella acanthopoda Rudilemboides stenopropodus Diplocirrus sp SD1Amphideutopus oculatus Scoletoma spPseudopolydora paucibranchiataScoletoma sp C Scoletoma erectaTheora lubrica Euphilomedes carcharodonta Glycera americana Anoplodactylus erectus Bivalvia Bulla gouldianaScoletoma sp ATubulanus polymorphus/pellucidusGobiidaeElasmopus sp Bemlos macromanusPodocerus fulamus Hyale sp Acteocina incultaSpirorbidaeLeptosynapta spPista agassiziMaldanidaeLeitoscoloplos pugettensisLeptochelia dubia Synaptotanais notabilis Exogone lourei Neanthes acuminata Cmplx Paracerceis sculpta Diadumene spChironomidaeTagelus spAmpithoe longimanaAmpithoe sp Nassarius tegula Lyonsia californica Paradexamine sp A Fabriciola limnicola Cirriformia sp BSolen rostriformisNaineris uncinataMacoma spArmandia brevis Mediomastus spMusculista senhousei Prionospio heterobranchia NematodaBarleeia sp NemerteaPlatyhelminthesCaprella californicaParanthura elegansAlia carinata Brania californiensis Amphipholis squamata Harmothoe imbricata Cmplx Megalomma pigmentum Pherusa capulataEdwardsia californica Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-72 The groupings of the embayments in Figure 13-37 appear to be based largely on the physical and hydrological conditions of the embayments. The embayments in Group A are characterized by exposed coastlines that experience good tidal flushing and, during the dry season, are not greatly impacted by freshwater from the upstream watershed. For all the embayments in Group A, salinities at the time of Phase II sampling were 33 ppt or greater, suggesting minimal freshwater influence. These conditions are reflected in the abundant and diverse infaunal communities in Group A embayments. In contrast, the embayments in Group C were characterized by sinuous and braided channels, restricted openings to the ocean, and a greater freshwater influence. Salinities in these embayments were lower than those in Group A, particularly in San Elijo Lagoon, and San Luis Rey River Estuary where salinities were less than 14 ppt. Coastal embayments characterized by reduced flushing rates and brackish conditions typically have lower species abundance and diversity. As discussed above, the physical and hydrological conditions in Buena Vista Lagoon were different from any of the other embayments; at the time of sampling, salinities in the lagoon were 4 ppt or lower and the lagoon was closed to the ocean. 13.5.1 Data Integration As discussed in Section 3.3.5, sediment chemistry, toxicity, and benthic infauna data were used to develop a ranking of the embayments across the County. For each of the embayments, the three elements of the monitoring program were ranked individually for each site (1 to 12 for the 12 embayments assessed) as follows: Sediment Chemistry – The Mean ERM quotient was used, where 1 represents low potential for toxicity and 12 represents higher potential for toxicity. Long et al. (1998) have established criteria based on mean ERM-Q values based on the probability of toxic responses in amphipod tests: < 0.10 low probability of a toxic response 0.11 to 1.0 medium probability of a toxic response > 1.0 high probability of a toxic response These criteria were used to determine the potential for toxicity from sediments based on the ERM-Q values calculated for each of the embayments. The results of the chemistry analyses indicated that the embayments fell into one of two groups based on mean ERM-Q values compared to the published criteria: those with ERM-Qs less than 0.10 and those with mean ERM-Qs between 0.11 and 1.0. None of the embayments had mean ERM-Qs > 1.0. Among the 12 embayments, three had mean ERM-Q values < 0.10: the Santa Margarita River Estuary, San Elijo Lagoon, and San Dieguito Lagoon. The remainder had mean ERM-Qs between 0.11 and 1.0. The results for each embayment are presented in Table 13-19. Sediment Toxicity – The results of the E. estuarius percent survival were used to rank each embayment where 1 represents lower toxicity and 12 represents higher toxicity. The results of the toxicity tests were compared using ANOVA with a Tukey multiple comparison test, where the percent survival for each embayment was compared to that of the control and to the other embayments. Analysis showed the data was not normally distributed; therefore the results were arcsin transformed prior to final analysis. The results of the statistical test indicated that the embayments could be broken into two groups based on percent survival of the test organisms: Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-73 Table 13-19. Chemistry and toxicity results and the associated relative ranks for each embayment. Embayment Chemistry (Mean ERM-Q) Chemistry Rank Toxicity (% Survival) Toxicity Rank SME 0.049 1 97% 2 OH 0.245 10 86% 6 SLE 0.122 5 92% 4 BVL 0.204 9 98% 1 AHL 0.122 5 85% 7 BL 0.124 6 66% 10 SEL 0.076 2 88% 5 SDL 0.088 3 66% 10 LPL 0.111 4 96% 3 MB 0.299 11 81% 8 SRE 0.140 8 79% 9 TRE 0.128 7 97% 2 Group 1: Mean percent survival not significantly different from that of the control (the Santa Margarita River Estuary, Oceanside Harbor, the San Luis Rey River Estuary, Buena Vista Lagoon, Agua Hedionda Lagoon, San Elijo Lagoon, Los Peñasquitos Lagoon, Mission Bay, the Sweetwater River Estuary and the Tijuana River Estuary) Group 2: Mean percent survival significantly different from that of the control (Batiquitos Lagoon and San Dieguito Lagoon) Benthic Infauna – The results of the benthic community structure indices (abundance, richness, diversity, evenness and dominance) were used to rank each embayment based on the biological community. For each index, the value calculated for each embayment was ranked from 1 to 12, where 1 represents the best relative score (e.g. highest diversity) and 12 represents the worst. The ranks for each index were then used to develop an overall relative summed rank (where 1 represents the lowest summed score and 12 represents the highest summed score) of each embayment relative to the other embayments. The results are summarized in Table 13-20. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-74 Table 13-20. Benthic community structure indices results and relative ranking for each embayment. Embayment Abundance Abundance Rank Rich Rich Rank H' H' Rank J J Rank Dom. Dom. Rank Summed Rank Overall Rank SME 141 11 11.0 9 1.73 5 0.74 2 3.67 5 32 5 OH 339 9 40.7 2 2.80 1 0.76 1 9.67 1 14 2 SLE 417 7 8.0 10 1.17 10 0.59 7 2.00 8 42 8 BVL 55 12 5.0 12 0.66 12 0.40 11 1.33 10 57 9 AHL 362 8 22.7 6 1.60 7 0.56 8 4.00 4 33 6 BL 955 1 24.3 5 1.41 9 0.49 9 2.00 8 32 2 SEL 443 6 5.7 11 0.89 11 0.64 4 1.67 9 41 7 SDL 772 5 16.3 8 1.71 6 0.62 5 3.33 6 30 4 LPL 811 4 29.3 4 1.58 8 0.47 10 3.00 7 33 6 MB 853 3 43.3 1 2.62 2 0.70 3 7.00 2 11 1 SRE 947 2 37.7 3 2.32 3 0.64 4 5.00 7 19 3 TRE 328 10 22.3 7 1.82 4 0.60 6 3.33 6 33 6 Abun.=Taxa Abundance, Rich.=Taxa Richness, H’=Shannon-Wiener Diversity Index, J=Evenness Index, and Dom.= Dominance Index. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-75 The chemistry, toxicity, and benthic community ranks for each embayment are presented in Table 13-21. Table 13-21. Relative rankings based on chemistry, toxicity, and benthic community structure for each embayment. Embayment Chemistry Rank Toxicity Rank Benthos Rank Summed Rank Overall Rank SME 1 2 5 8 1 OH 10 6 2 18 6 SLR 5 4 8 17 5 BVL 9 1 9 19 7 AHL 5 7 6 18 6 BL 6 10 2 18 6 SEL 2 5 7 14 3 SDL 3 10 4 17 5 LPL 4 3 6 13 2 MB 11 8 1 20 8 SRE 8 9 3 20 8 TRE 7 2 6 15 4 In general, there was a poor association between the three rankings among the embayments, as shown in Figure 13-38. The Spearman Rank Correlation Coefficient was 0.11 for chemistry rank versus toxicity rank, -0.497 for chemistry rank versus benthic community rank, and -0.64 for toxicity rank versus benthic community rank. These results reflect the complex and dynamic nature of coastal estuaries as well as the limitations of the sampling regimen. For instance, the poor association between chemistry and toxicity may have been a result of a limited suite of constituents for which the sediments were analyzed. In several embayments where the mean ERM-Qs were low, sediment toxicity was high (e.g. San Dieguito Lagoon). This suggests that other contaminants that were not assessed as part of the program may have been responsible for the elevated toxicity in these embayments. In other cases, such as Buena Vista Lagoon, the opposite pattern was observed. Neither sediment chemistry nor toxicity was positively correlated with the benthic community structure. This likely reflects the dynamic nature of coastal estuaries. These environments are influenced by frequent changes in water quality (particularly salinity), sediment composition, temperature, and nutrient availability, all of which contribute to the structure of the benthic community. Additional data collected in subsequent years of the ABLM Program may help strengthen these relationships. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-76 A) Toxicity vs Chemistry R2 = 0.019 0 2 4 6 8 10 12 024681012 Chemistry RankToxicity RankB) Benthos vs Chemistry R2 = 0.148 0 1 2 3 4 5 6 7 8 9 10 024681012 Chemistry RankOverall Benthos RankC) Benthos vs Toxicity R2 = 0.509 0 1 2 3 4 5 6 7 8 9 10 024681012 Toxicity RankOverall Benthos Rank Figure 13-38. Relative ranking correlations between toxicity and chemistry (A), benthic community and chemistry (B), and benthic community and toxicity (C). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-77 Figure 13-39 compares the overall relative ranks of the 12 embayments sampled in the ABLM Program in the summers of 2003 and 2004. An increase in overall ranking (therefore a decrease in relative quality) was found at four embayments (the San Luis Rey River Estuary, San Dieguito Lagoon, Mission Bay, and the Tijuana River Estuary). A decrease in overall ranking (an increase in relative quality) was found at the Santa Margarita River Estuary, Oceanside Harbor, Buena Vista Lagoon, Agua Hedionda Lagoon, Batiquitos Lagoon, San Elijo Lagoon, Los Peñasquitos Lagoon, and the Sweetwater River Estuary. The greatest change was observed at San Elijo Lagoon; this site was ranked 11th in 2003 and 3rd in 2004. Summary and Conclusions In the summer of 2004 sediments in the twelve major coastal embayments in San Diego County were monitored to assess the potential for adverse effects from the watershed and to compare sediment quality among the embayments. In Phase I, a stratified random approach was used to identify the three sites in each embayment where COCs were most likely to be found (i.e., those with the highest TOC and smallest grains size). Buena Vista Lagoon had a much higher percentage of TOC and fine grained sediments than the other embayments. In contrast, sediments in Santa Margarita River Estuary contained a much lower TOC content and percentage of fine-grained particles than the other embayments. This pattern was also seen in the 2003 ABLM sampling. In Phase II of the assessment, the three sites identified in Phase I for each embayment were sampled and analyzed for chemistry, toxicity, and benthic community structure. For the chemistry assessment, composite sediment samples from each embayment were analyzed for metals, PCBs, PAHs, and pesticides. PCBs, PAHs, and pesticides were not detected in any of the embayments. A suite of six metals was found in all 12 embayments: arsenic, chromium, copper, lead, nickel, and zinc. In general, concentrations of metals were low in all embayments and there were no metals that exceeded their ERM thresholds. However, several metals exceeded ERL values, including copper (exceeded the ERL at three sites), arsenic (exceeded the ERL at four sites), zinc (exceeded the ERL at three sites), and lead (exceeded the ERL at one site). The mean ERM-Q value, which represents the cumulative impact from all COC for which ERMs are available, was greatest at Mission Bay and Oceanside Harbor and lowest at the Santa Margarita River Estuary and San Elijo Lagoon. For the toxicity assessment, the percent survival of a marine amphipod exposed to sediments from each of the embayments was compared to that of a control. Percent survival was not significantly different from that of the control for ten embayments: the Santa Margarita River Estuary, Oceanside Harbor, the San Luis Rey River Estuary, Buena Vista Lagoon, Agua Hedionda Lagoon, San Elijo Lagoon, Los Peñasquitos, Mission Bay, the Sweetwater River Estuary, and the Tijuana River Estuary. The two remaining embayments where percent survival was significantly different from that of the control were Batiquitos Lagoon and San Dieguito Lagoon. Comparison of 2003 and 2004 ABLM Embayments 0 2 4 6 8 10 12 14SMEOHSLEBVLAHLBLSELSDLLPLMBSRETRE EmbaymentsRank 2004 data 2003 data Figure 13-39. Relative ranking comparison between the 2003 and 2004 ABLM Programs. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-78 For the benthic community assessment, animals collected from the sediment at three sites in each embayment were identified to the lowest possible taxonomic level. Several indices of benthic community structure were then calculated, including abundance, richness, diversity, evenness, and dominance. For each embayment the scores from these indices were ranked and the summed ranks were used to compare the benthic communities among the 12 embayments. Based on this overall ranking, the embayments with the best relative benthic communities were Mission Bay, the Sweetwater River Estuary, Batiquitos Lagoon, Oceanside Harbor, the Santa Margarita River Estuary, and San Dieguito Lagoon. Those with the worst relative benthic communities were Buena Vista Lagoon, Agua Hedionda Lagoon, Los Peñasquitos Lagoon, the Tijuana River Estuary, the San Luis Rey River Estuary, and San Elijo Lagoon. The experimental design for the ABLM Program was based on a presumed positive correlation between COC, TOC content, and grain size, where higher COC concentrations are expected in areas with higher TOC and smaller grain size. The results of the ABLM Program indicate a strong, positive relationship between mean ERM-Qs, TOC content, and percentage of fine-grained sediments. These results help validate the approach utilized in the ABLM Program. However, the relationships between sediment chemistry, toxicity, and benthic community structure were weak. This is likely due to the dynamic nature of coastal estuaries and a limited number of samples and analyses. Results from samples collected in subsequent years of the ABLM Program may help to strengthen these relationships. 13.6 Coastal Outfall Data 13.6.1 Coastal Outfall Data Analysis Results for San Diego County The data used in this assessment was collected from April 1, 2004 through March 31, 2005 by the Copermittees. During this period, paired samples were collected from 35 stations located at coastal beaches throughout San Diego County and analyzed for bacterial indicators. A paired sample is defined as one sample collected from a designated storm drain with an additional sample collected concurrently in the adjacent receiving water. Approximately 29 stations sampled during this period are at the same location as those monitored last year, but the total number of stations included in the assessment increased from 32 to 35. A total of 325 paired samples were collected during the 2004-05 monitoring period. The majority of the sample pairs (232) were collected during the dry period (April 1, 2004 through October 31, 2004). Out of 325 sample pairs, only 8 (2.5%) had a receiving water sample which exceeded AB 411 criteria and simultaneously exceeded the storm drain criterion for any of the bacterial indicators. The Boat Wash site had concentrations exceeding the criterion in seven paired samples; four for total coliform and three for fecal coliform (with a simultaneous exceedance of both indicators on only one sample date). PB Point exceeded in both the storm drain and receiving water with one sample for enterococcus. The majority of sample pairs (276 or 85%) did not exceed either the receiving water or the storm drain criteria. Out of the 325 paired samples, 152 (46.8%) had storm drain discharges or flow that did not reach the receiving water; 31 (9.5%) did not have documentation to indicate whether the storm drain flow reached the receiving water; and 142 (43.7%) were documented to have storm drain discharge reaching the receiving water. Therefore, out of 142 paired samples for which the storm drain flow reached the receiving water, only 8 (5.6%) exceeded the criteria at both sample locations. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-79 The data was reviewed separately for the dry and wet seasons and it shows varied results for the two datasets: 37.2% of the paired samples taken during dry weather did not reach the receiving water; whereas only 9.5% of the paired samples for wet weather did not reach the receiving water. Paired sample data for each of the three bacterial indicators (total and fecal coliform and enterococcus) was graphed for each of the 35 stations. The x-axis shows from left to right (north to south) the station names and the y-axis is the bacterial indicator concentration. For each coastal outfall sampling station, data is shown for the receiving water sample (Figures 13-40 through 13-42) and storm drain outfall sample (Figures 13-43 through 13-45). The geometric mean of the data for each sampling station is represented by the blue dot and the range of test values is shown as vertical bars (unless all samples had the same value or only one sample was collected). It should be noted that in some instances the geometric mean represents as few as three sampling events. For each bacterial indicator, the applicable AB 411 single sample water quality criteria are show for receiving water data, and the Copermittee action levels based on a 95th percentile confidence interval are shown for storm drain data. Receiving water samples Samples taken in the receiving water for total coliform bacteria had geometric mean concentrations significantly below the AB 411 action level at all but one of the 35 beach shore sample sites monitored in 2004-05 (Figure 13-40). The geometric mean concentration at the Boat Wash site was in excess of 21,000 MPN/100ml. The graph for total coliform shows the lower detection limit used by the City of Encinitas (Moonlight Beach, Swami’s, Swami’s Mid Beach, and N. San Elijo State Beach). Only the Boat Wash site had samples that exceeded the AB 411 single sample criteria. PB Point was noted last year to have exceeded AB 411 criteria, however, this year there were no exceedances. Additionally, the geometric mean at PB Point was slightly lower this year than last. There are twelve sites with geometric means equal to or less than 10 MPN/100ml. The lowest geometric mean values correspond to the stations sampled at Carlsbad Village Drive and Swami’s Mid Beach, with a low value also recorded from the single sample taken at the beach at the end of 8th Street. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-80 Boat WashSurfriderSt. Malo NorthCypressChristianson WayCarlsbad Village DrPine AveMoonlight BeachSwami'sSwami's Mid BeachN San Elijo State BeachSeascape17th St.15th St.Between 13th and 15th12th St.Beach at the end of 8th St.South End of BeachEl Paseo GrandeCamino Del OroAvenida De La PlayaRavinaVista De La PlayaBonairPlaya Del NortePB PointTourmalineGrand AvePoint Loma AveKellogg St.VallecitosShelter IslandTidelands ParkBayside ParkSpanish Landing1 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Total Coliform (MPN/100ml)Receiving Water Station AB411 Range Geometric mean Note: Geometric means without a range bar represent single samples. Figure 13-40. Total coliform at coastal outfall receiving water stations (2004-05). Fecal coliform geometric means were also below AB 411 criteria for most of the beach shore sampling locations (Figure 13-41). The highest geometric mean was found at the Boat Wash site. Although the highest geometric mean over the past two years was recorded at Shelter Island, this site had concentrations below both the AB 411 standards during this monitoring period. Single sample exceedances were recorded for Boat Wash, PB Point, and Ravina. The lowest geometric mean was found at El Paseo Grande. Also low was the result from the single sample taken at the beach at the end of 8th Street. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-81 Boat WashSurfriderSt. Malo NorthCypressChristianson WayCarlsbad Village DrPine AveMoonlight BeachSwami'sSwami's Mid BeachN San Elijo State BeachSeascape17th St.15th St.Between 13th and 15th12th St.Beach at the end of 8th St.South End of BeachEl Paseo GrandeCamino Del OroAvenida De La PlayaRavinaVista De La PlayaBonairPlaya Del NortePB PointTourmalineGrand AvePoint Loma AveKellogg St.VallecitosShelter IslandTidelands ParkBayside ParkSpanish Landing1 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Fecal Coliform (MPN/100ml)Receiving Water Station AB411 Range Geometric mean Note: Geometric means without arangebar represent single samples. Figure 13-41. Fecal coliform at coastal outfall receiving water stations (2004-05). Lastly, enterococcus data collected in 2004-05 shows the geometric mean for Boat Wash to exceed AB 411 criteria (Figure 13-42). The value for Shelter Island also approached the geometric mean criteria of 35 MPN/100ml. The remaining locations had geometric means below AB 411 criteria. Several additional stations had single sample exceedances, including the site between 13th and 15th Streets, Ravina, Playa del Norte, PB Point, Point Loma Avenue, Vallecitos, and Spanish Landing. The lowest enterococcus levels in the receiving water were found at Swami’s, Swami’s mid beach, and N. San Elijo State Beach (all of these sites were analyzed using lower detection limits). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-82 Boat WashSurfriderSt. Malo NorthCypressChristianson WayCarlsbad Village DrPine AveMoonlight BeachSwami'sSwami's Mid BeachN San Elijo State BeachSeascape17th St.15th St.Between 13th and 15th12th St.Beach at the end of 8th St.South End of BeachEl Paseo GrandeCamino Del OroAvenida De La PlayaRavinaVista De La PlayaBonairPlaya Del NortePB PointTourmalineGrand AvePoint Loma AveKellogg St.VallecitosShelter IslandTidelands ParkBayside ParkSpanish Landing1 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Enterococcus (MPN/100ml)Receiving Water Station AB411 Range Geometric mean Note: Geometric means without a rangebarrepresent single samples. Figure 13-42. Enterococcus at coastal outfall receiving water stations (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-83 Storm drain outfall samples For total coliform (Figure 13-43), the majority of the stations (30 out of 35 or 85.7%) had geometric mean values below the Copermittee-based action level, and 15 stations (42.9%) had geometric means below both AB 411 and action level criteria. Geometric means were the lowest at Swami’s, Swami’s Mid Beach, and Playa del Norte, with low values also being recorded from the single samples at Surfrider and St. Malo North. The highest geometric means were found at Carlsbad Village Drive, Seascape, Boat Wash, and Tidelands Park, with a high value being recorded from the single sample at the beach and the end of 8th Street. Boat WashSurfriderSt. Malo NorthCypressChristianson WayCarlsbad Village DrPine AveMoonlight BeachSwami'sSwami's Mid BeachN San Elijo State BeachSeascape17th St.15th St.Between 13th and 15th12th St.Beach at the end of 8th St.South End of BeachEl Paseo GrandeCamino Del OroAvenida De La PlayaRavinaVista De La PlayaBonairPlaya Del NortePB PointTourmalineGrand AvePoint Loma AveKellogg St.VallecitosShelter IslandTidelands ParkBayside ParkSpanish Landing10 100 1,000 10,000 100,000 1,000,000 10,000,000 100,000,000 Total Coliform (MPN/100ml)Storm Drain Storm Drain Criterion AB411 Range Geometric mean Note: Geometric means without a rangebarrepresent single samples. Figure 13-43. Total coliform at coastal storm drain outfalls (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-84 Fecal coliform data shows that 33 out of 35 (94.3%) had geometric mean values below the storm drain action level, and 15 stations (42.9%) had geometric means below both AB 411 and action level criteria (Figure 13-44). As with total coliform, geometric means were the lowest at Swami’s, Swami’s Mid Beach, and Playa del Norte, with low values also being recorded from the single samples at Surfrider and St. Malo North. The highest geometric means were found at Carlsbad Village Drive and Cypress. Boat WashSurfriderSt. Malo NorthCypressChristianson WayCarlsbad Village DrPine AveMoonlight BeachSwami'sSwami's Mid BeachN San Elijo State BeachSeascape17th St.15th St.Between 13th and 15th12th St.Beach at the end of 8th St.South End of BeachEl Paseo GrandeCamino Del OroAvenida De La PlayaRavinaVista De La PlayaBonairPlaya Del NortePB PointTourmalineGrand AvePoint Loma AveKellogg St.VallecitosShelter IslandTidelands ParkBayside ParkSpanish Landing1 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Fecal Coliform (MPN/100ml)Storm Drain Storm Drain Criterion AB411 Range Geometric mean Note: Geometric means without a rangebar represent single samples. Figure 13-44. Fecal coliform at coastal storm drain outfalls (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-85 Lastly, enterococcus data (Figure 13-45) shows only one geometric mean above the storm drain criterion from a single sample collected from Tidelands Park. However, 27 stations (77.1%) had geometric means above the AB 411 criteria but below the storm drain criterion. Only 20% of the stations had geometric means below the AB 411 criteria. Of these, the lowest geometric mean values were based on single samples and were found at Surfrider and St. Malo North. Boat WashSurfriderSt. Malo NorthCypressChristianson WayCarlsbad Village DrPine AveMoonlight BeachSwami'sSwami's Mid BeachN San Elijo State BeachSeascape17th St.15th St.Between 13th and 15th12th St.Beach at the end of 8th St.South End of BeachEl Paseo GrandeCamino Del OroAvenida De La PlayaRavinaVista De La PlayaBonairPlaya Del NortePB PointTourmalineGrand AvePoint Loma AveKellogg St.VallecitosShelter IslandTidelands ParkBayside ParkSpanish Landing1 10 100 1,000 10,000 100,000 1,000,000 Enterococcus (MPN/100ml)Storm Drain Storm Drain Criterion AB411 Range Geometric mean Note: Geometric means without a rangebarrepresent single samples. Figure 13-45. Enterococcus at coastal storm drain outfalls (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-86 13.6.2 Coastal Lagoon Outfall Data Analysis Results for San Diego County The data used in this assessment was collected from April 1, 2004 through March 31, 2005 by the Copermittees. During this period, 25 storm drain outfall stations were monitored around San Diego County lagoons for bacterial indicators. Efforts were made to collect paired samples from the storm drain and at the shore, however, limited access at some sites prevented the collection of receiving water samples. For this reason, there were 10 sites where paired samples were collected, whereas only storm drain samples were collected at the other 15 stations. A total of 121 paired samples were collected during this period. The majority of the samples (93 or 76.9%) were collected during the dry period (April 1, 2004 through October 31, 2004). Of these, there were only eight receiving water exceedances and four storm drain exceedances. Wet weather samples accounted for 23.1% of the total samples. There were no receiving water or storm drain exceedances during wet weather. Out of 121 total paired samples, 4 (3.3%) had a receiving water sample which exceeded Basin Plan and/or AB 411 criteria and simultaneously exceeded the storm drain criterion for any of the bacterial indicators. For all four of these samples, storm drain flow was observed to reach the receiving water. A total of110 samples (90.9%) did not exceed receiving water or storm drain criteria. Paired sample data for each of the three bacterial indicators (total and fecal coliform and enterococcus) was graphed for each of the 25 stations. The x-axis shows from left to right (north to south) the station names and the y-axis is the bacterial indicator concentration. For each lagoon outfall sampling station, data is shown for the receiving water sample (Figures 13-46 through 13-48) and storm drain outfall sample (Figures 13-49 through 13-51). The geometric mean of the data for each sampling station is represented by the dot and the range of test values is shown as vertical bars (unless all samples had the same value or only one sample was collected). It should be noted that in some instances the geometric mean represents as few as three sampling events. For each bacterial indicator, the applicable AB 411 water quality criteria are shown. Receiving water samples Samples taken in the lagoon receiving water for total coliform bacteria had geometric mean concentrations significantly below the AB 411 action level at all but one of the 10 beach shore sample sites monitored in 2004-05 (Figure 13-46). The graph for total coliform shows the station Buena Vista Lagoon #1 had a majority of the samples above the AB 411 standard and consequently the geometric mean was above 10,000 MPN/100ml. This is consistent with similar results from 2003. The only other site with single sample exceedances was Chinquapin at RR tracks. All other locations were consistently below standards. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-87 Buena Vista Lagoon #1Buena Vista Lagoon #2Chinquapin at RR tracksHoover StPrivate marinaPark and ValenciaPark and KellyCannon and LegolandCabrillo Power PlantSed basin off WindroseAviara Golf course at entranceAviara Golf course E of entranceLa Costa and ECRLa Costa Ave E of Saxony -E&W pipesLa Costa Av E of I-5 300'LT Preserve at Carlsbad BlvdCardiff Channel @ Hwy 101San Elijo AveMacKinnon Ranch RoadSEJPA channelMira Costa College Detention BasinPenasquitos 03Penasquitos 08Penasquitos 10Penasquitos 111 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Total Coliform (MPN/100ml)Lagoon Receiving Water Station AB411 Range Geometric mean Note: Geometric means without a range bar represent single samples. Figure 13-46. Total coliform at coastal lagoon outfall receiving water stations (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-88 Fecal coliform geometric means were compared to AB 411 criteria and found to exceed only at Buena Vista Lagoon #1 (Figure 13-47). Other single sample exceedances were noted at Chinquapin at RR tracks, Cardiff Channel at Highway 101, and SEJPA Channel. Buena Vista Lagoon #1Buena Vista Lagoon #2Chinquapin at RR tracksHoover StPrivate marinaPark and ValenciaPark and KellyCannon and LegolandCabrillo Power PlantSed basin off WindroseAviara Golf course at entranceAviara Golf course E of entranceLa Costa and ECRLa Costa Ave E of Saxony -E&W pipesLa Costa Av E of I-5 300'LT Preserve at Carlsbad BlvdCardiff Channel @ Hwy 101San Elijo AveMacKinnon Ranch RoadSEJPA channelMira Costa College Detention BasinPenasquitos 03Penasquitos 08Penasquitos 10Penasquitos 111 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Fecal Coliform (MPN/100ml)Lagoon Receiving Water Station AB411 Range Geometric mean Note: Geometric means without a range bar represent single samples. Figure 13-47. Fecal coliform at coastal lagoon outfall receiving water stations (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-89 Lastly, enterococcus data collected in 2004-05 was compared to 1994 San Diego Region Basin Plan water quality objectives for various types of water contact recreation (Table 13-22). The water quality objective is shown on Figure 13-48 (and in Table 13-22) to vary according to the water contract subcategory designated for each station. Table 13-22. Enterococci water quality objectives for saltwater in REC-1 waterbodies. Water Contact Recreation Type Subcategory Saltwater enterococci (CFU/100ml) Steady State All areas 35 Designated beach 104 Moderately or lightly used area 276 Maximum Infrequently used area 500 Buena Vista Lagoon #1Buena Vista Lagoon #2Chinquapin at RR tracksHoover StPrivate marinaPark and ValenciaPark and KellyCannon and LegolandCabrillo Power PlantSed basin off WindroseAviara Golf course at entranceAviara Golf course E of entranceLa Costa and ECRLa Costa Ave E of Saxony -E&W pipesLa Costa Av E of I-5 300'LT Preserve at Carlsbad BlvdCardiff Channel @ Hwy 101San Elijo AveMacKinnon Ranch RoadSEJPA channelMira Costa College Detention BasinPenasquitos 03Penasquitos 08Penasquitos 10Penasquitos 111 10 100 1,000 10,000 100,000 1,000,000 10,000,000 Enterococcus (MPN/100ml)Lagoon Receiving Water Station REC 1 Range Geometric mean Note: Geometric means without a range bar represent single samples. Figure 13-48. Enterococcus at coastal lagoon outfall receiving water stations (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-90 The receiving water data shows the geometric mean for enterococcus above Basin Plan water quality objectives for Buena Vista Lagoon #1. The remaining locations had geometric means below the Basin Plan water quality objectives. Chinquapin at RR tracks, Cardiff Channel at Highway 101, and SEJPA Channel all had single sample exceedances. The lowest enterococcus levels in the receiving water were found at Peñasquitos 08. Storm drain outfall samples For total coliform, the majority of the stations (20 out of 25 or 80%) had geometric mean values below AB 411 criteria (Figure 13-49). Geometric means equal to or greater than AB 411 criteria were found at Buena Vista Lagoon #1, Park and Valencia (based on a single sample), Sed basin off Windrose, Peñasquitos 10, and Peñasquitos 11. Buena Vista Lagoon #1Buena Vista Lagoon #2Chinquapin at RR tracksHoover StPrivate marinaPark and ValenciaPark and KellyCannon and LegolandCabrillo Power PlantSed basin off WindroseAviara Golf course at entranceAviara Golf course E of entranceLa Costa and ECRLa Costa Ave E of Saxony -E&W pipesLa Costa Av E of I-5 300'LT Preserve at Carlsbad BlvdCardiff Channel @ Hwy 101San Elijo AveMacKinnon Ranch RoadSEJPA channelMira Costa College Detention BasinPenasquitos 03Penasquitos 08Penasquitos 10Penasquitos 1110 100 1,000 10,000 100,000 1,000,000 10,000,000 Total Coliform (MPN/100ml)Lagoon Storm Drain Station AB411 Range Geometric mean Note: Geometric means without a range bar represent single samples. Figure 13-49. Total coliform at coastal lagoon storm drain outfall stations (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-91 Fecal coliform data represented graphically in Figure 13-50 shows that only 9 (36%) of the outfalls had geometric mean values below the AB 411 criteria of 400 MPN/100mL. The highest geometric means were found at Peñasquitos 10 and at Park and Valencia (based on a single sample). With the exception of two single samples taken at sites on La Costa Avenue (E of Saxony – E&W pipes and E of 1-5 300’), every station had samples that exceeded AB 411 single sample criteria. Buena Vista Lagoon #1Buena Vista Lagoon #2Chinquapin at RR tracksHoover StPrivate marinaPark and ValenciaPark and KellyCannon and LegolandCabrillo Power PlantSed basin off WindroseAviara Golf course at entranceAviara Golf course E of entranceLa Costa and ECRLa Costa Ave E of Saxony -E&W pipesLa Costa Av E of I-5 300'LT Preserve at Carlsbad BlvdCardiff Channel @ Hwy 101San Elijo AveMacKinnon Ranch RoadSEJPA channelMira Costa College Detention BasinPenasquitos 03Penasquitos 08Penasquitos 10Penasquitos 1110 100 1,000 10,000 100,000 1,000,000 10,000,000 Fecal Coliform (MPN/100ml)Lagoon Storm Drain Station AB411 Range Geometric mean Note: Geometric means without a rangebar represent single samples. Figure 13-50. Fecal coliform at coastal lagoon storm drain outfall stations (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-92 Lastly, enterococcus data (Figure 13-51) for coastal storm drain outfalls was again compared to Basin Plan water quality criteria varying by the subcategory of REC-1 use as shown in Table 13-22. The data shows that 8 out of 25 (32%) of the stations had geometric means below the Basin Plan water quality objectives. The lowest geometric mean values were found in the single samples taken from the 3 sites on La Costa Avenue. As with fecal coliform, the highest geometric means for enterococcus were found at Peñasquitos 10 and at Park and Valencia (based on a single sample). Buena Vista Lagoon #1Buena Vista Lagoon #2Chinquapin at RR tracksHoover StPrivate marinaPark and ValenciaPark and KellyCannon and LegolandCabrillo Power PlantSed basin off WindroseAviara Golf course at entranceAviara Golf course E of entranceLa Costa and ECRLa Costa Ave E of Saxony -E&W pipesLa Costa Av E of I-5 300'LT Preserve at Carlsbad BlvdCardiff Channel @ Hwy 101San Elijo AveMacKinnon Ranch RoadSEJPA channelMira Costa College Detention BasinPenasquitos 03Penasquitos 08Penasquitos 10Penasquitos 1110 100 1,000 10,000 100,000 1,000,000 10,000,000 Enterococcus (MPN/100ml)Lagoon Storm Drain Station REC 1 Range Geometric mean Note: Geometric means without a range bar represent single samples. Figure 13-51. Enterococcus at coastal lagoon storm drain outfall stations (2004-05). Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-93 13.7 Third Party Regional Data Third party data includes data collected in 2002 from the Carlsbad watershed, the Los Peñasquitos Creek watershed and the Mission Bay watershed under the Surface Water Ambient Monitoring Program (SWAMP), in addition to the Padre Dam Water Quality Monitoring Program conducted in the San Diego River watershed. 13.7.1 Surface Water Ambient Monitoring Program (SWAMP) Third party data was collected in 2002 under the Surface Water Ambient Monitoring Program (SWAMP) and was provided by the San Diego Regional Water Quality Control Board. Data was collected from the Carlsbad watershed, the Los Peñasquitos Creek watershed and the Mission Bay watershed (See Sections 6.2.3, 8.2.3 and 9.2.3, respectively, for complete details). Results are presented in Appendix H. There were 10 sampling locations within the Carlsbad watershed, including Loma Alta Creek, Buena Vista Creek, Buena Creek, Agua Hedionda Creek, San Marcos Creek, Encinitas Creek, Cottonwood Creek and Escondido Creek. Data collected from Agua Hedionda Creek and Escondido Creek were compared to the mass loading station and dry weather data results to provide qualitative assessments with current wet and dry weather results. The remaining stations within the watershed were too spatially disconnected from the MLS to correlate the data with any of the wet and dry weather monitoring results, however, exceedances were noted. At the station located on Agua Hedionda Creek upstream of the MLS, there were water quality objective exceedances for sulfate, manganese and toxicity. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedances were for toxicity to Ceriodaphnia and Hyalella. Two sampling locations were located on Escondido Creek: one was located upstream of the MLS while the second location was in the same vicinity as the MLS. There were water quality objective exceedances for pH, sulfate, manganese, Diazinon and toxicity at both stations. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedances were for Diazinon and Ceriodaphnia survival and reproduction. Exceedances observed at the other seven stations within the Carlsbad watershed were similar to exceedances in Agua Hedionda Creek and Escondido Creek. Sulfate, manganese and toxicity consistently exceeded objectives at all sites. Other parameters, including pH, nitrate/nitrite as N and Diazinon exceeded objectives sporadically. There were three sampling sites within Los Peñasquitos watershed, including Los Peñasquitos Creek, Soledad Canyon Creek and Poway Creek. Data collected from Los Peñasquitos Creek were compared to the mass loading station and dry weather data results to provide qualitative assessments with current wet and dry weather results. The other two stations within the watershed were too spatially disconnected from the MLS to correlate the data with any of the wet and dry weather monitoring results, however, exceedances were noted. At the station located on Los Peñasquitos Creek in the same vicinity as the mass loading station, there were water quality objective exceedances for turbidity, pH, sulfate, Diazinon, methyl parathion and toxicity. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedances were for turbidity during wet and dry weather and Diazinon during wet weather, however these exceedances were not persistent. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-94 Exceedances observed at the other two stations within Los Peñasquitos watershed were similar to exceedances that were found in Los Peñasquitos Creek. Sulfate, manganese and toxicity consistently exceeded objectives at all sites. Turbidity and Diazinon concentrations only exceeded objectives sporadically. There were two sampling sites within the Mission Bay watershed located on Tecolote Creek near the mass loading station and on Rose Canyon Creek. Data collected from Tecolote Creek were compared to the mass loading station and dry weather data results to provide qualitative assessments with current wet and dry weather results. The Rose Canyon Creek station was too spatially disconnected from the MLS to correlate the data with any of the wet and dry weather monitoring results, however, exceedances were noted. There were water quality objective exceedances for sulfate, manganese and toxicity at the Tecolote Creek station. Comparing the third party data with wet weather MLS data and dry weather data collected upstream of the MLS, the only common exceedance was for toxicity during wet weather. Exceedances observed at Rose Canyon Creek included sulfate, manganese, turbidity, pH, Diazinon and toxicity. 13.7.2 Padre Dam Water Quality Monitoring Program The Padre Dam Water Quality Monitoring Program consists of monthly sampling at six stations located on the San Diego River, or tributaries thereof, within the City of Santee. Water samples are collected for 13 analytical constituents and 8 field measurements. The eight field measurements are dissolved oxygen, dissolved oxygen saturation (%), pH, conductivity, water temperature, turbidity, flow rate, and chlorophyll-A. Sediment values were not analyzed in this report due to a lack of relative comparable data, but are presented to show complete scope of the Padre Dam sampling effort. The data collected under the Padre Dam Water Quality Monitoring Program was compared to the benchmark water quality objectives used at the mass loading stations (MLS) in each of the watersheds (Table 13-23). Exceedances of water quality objectives are shown in red with gray backgrounds. For turbidity, 20 NTU OR JTU was used. For dissolved oxygen, the water quality objective of 5.0 mg/L applicable to inland surface waters with the designated MAR and WARM beneficial use was applied (Basin Plan 1994). The WARM beneficial use applies in the waterbodies monitored. Field test results showing dissolved oxygen levels less than 5.0 mg/L were marked as exceedances. The Padre Dam monitoring results for E. coli were compared to the freshwater maximum for REC-1 designated beaches water quality objective of 235 MPN/100 mL (Basin Plan 1994). The results for fecal coliform were compared to the water quality objective of 400 MPN/100ml for the MLS in the San Diego River Watershed Management Area. The acceptable range for pH is between 6.5 and 8.5 units (Basin Plan 1994). No comparisons were performed against water quality objectives for conductivity, water temperature, and total coliform. There are no water quality objectives for flow rate, chlorophyll-A, dissolved oxygen saturation, organic nitrogen, and total nitrogen as (N). 13.7.2.1 Summary of Third Party Data Monitoring Locations The Padre Dam monitoring program for 2004 was comprised of six stations, including three located on the San Diego River, two on tributary creeks (Forrester Creek and Sycamore Creek), and one station on one of the Mission Ponds. Sediment samples were also collected at these sites. A summary of the stations and measurements associated with each is provided in Table 13-24. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-95 Table 13-23. Padre Dam Water Quality Monitoring results. CONSTITUENT SAMPLE POINT Units WQO 5-Jan-2004 2-Feb-2004 1-Mar-2004 5-Apr-2004 3-May-2004 7-Jun-2004 6-Jul-2004 2-Aug-2004FLOW RATE #1 Carlton Hills Blvd. mgd 1.37 3.1 58.94 0.36 2.49 0.288 1.61 1.61#2 Forrestor Creek 0.564 0.233 5.23 0.711 0.627 0.679 0.22 0.341#4 Sycamore Creek leaving Golf Course 1.55 15.5 3.1 1.63 0.727 0.165 0.052 NF#5 Mast Boulevard 4.96 14 14.4 4.39 2.46 2.51 0.026 1.45#6 Old Mission Dam 3 8.27 29.08 6.07 3.82 2.54 0.037 0.03#7 Mission Ponds 17.2 24.6 52.35 36.7 1.83 0.373 0.038 NFpH #1 Carlton Hills Blvd. units 6.5-8.5 7.56 7.54 7.52 7.51 7.58 7.67 7.74 7.74#2 Forrestor Creek 7.9 7.54 8.2 7.99 8.01 7.8 7.74 7.71#4 Sycamore Creek leaving Golf Course 7.71 7.7 7.49 7.57 7.6 7.68 7.73 7.76#5 Mast Boulevard 7.66 7.02 7.64 7.75 7.73 7.73 7.69 7.64#6 Old Mission Dam 7.55 7.77 7.62 7.52 7.77 7.8 7.92 7.76#7 Mission Ponds 7.53 7.39 7.54 7.78 7.56 7.6 7.72 7.72CONDUCTIVITY #1 Carlton Hills Blvd. umhos 1651 1866 1006 1555 1856 2190 2280 2280#2 Forrestor Creek 1235 1866 2430 2530 2850 2950 2930 2930#4 Sycamore Creek leaving Golf Course 1445 832 1289 2160 1920 2430 2610 2770#5 Mast Boulevard 1683 1886 1243 1964 2210 2540 2680 2710#6 Old Mission Dam 1122 1877 1189 1521 2140 2490 2670 2810#7 Mission Ponds 1545 2160 846 2180 2180 2670 3030 3420TEMPERATURE #1 Carlton Hills Blvd. deg. C 7.9 10.3 11.8 19.1 20.5 20.1 22.2 22.2#2 Forrestor Creek 7 9.3 11.8 20.4 6.17 20.6 22.4 22#4 Sycamore Creek leaving Golf Course 9 10.2 13.3 19.3 20.2 20.1 23.1 20.8#5 Mast Boulevard 10.4 11.2 13.3 19.3 19.7 20 20.9 21#6 Old Mission Dam 11.8 10.8 12.6 18 22.4 20.8 22.6 21.4#7 Mission Ponds 13.7 10.8 14.2 23.5 25.5 20.1 23.7 20.1TOTAL DISSOLVED SOLIDS #1 Carlton Hills Blvd. mg/L 1032 1136 592 920 1080 1368.75 1464 1464#2 Forrestor Creek 1235 1436 1692 1564 1756 1843.75 1572 1788#4 Sycamore Creek leaving Golf Course 5.77 832 824 1288 1200 1518.75 1312 1620#5 Mast Boulevard 1052 1156 812 1172 1332 1587.5 1820 1644#6 Old Mission Dam 701 1144 784 892 1280 1556.25 1544 1660#7 Mission Ponds 957 1448 576 1296 1320 1668.75 1592 2080TURBIDITY #1 Carlton Hills Blvd. NTU 0.632 0.622 7.2 1.33 5.15 7.09 3.32 3.32#2 Forrestor Creek 7.2 0.622 7.65 2.25 1.72 2.98 3.87 3.52#4 Sycamore Creek leaving Golf Course 5.77 3.28 61.8 6.74 3.76 4.58 0.119 19#5 Mast Boulevard 7.29 3.01 1.47 3.87 3.94 3.37 3.43 4.76#6 Old Mission Dam 3.99 2.17 1.33 7.15 8.41 8.84 9.93 3.36#7 Mission Ponds 7.76 5.05 32.3 6.23 3.19 2.2 4.38 6.38D.O. SATURATION #1 Carlton Hills Blvd. % 65.8 0.647 0.521 37.4 0.43 0.486 0.625 0.625#2 Forrestor Creek 75 0.672 0.8 75.5 0.685 0.586 0.579 0.424#4 Sycamore Creek leaving Golf Course 79 0.456 0.575 23.3 0.212 0.23 0.3 0.5#5 Mast Boulevard 72.7 0.664 0.532 38.3 0.569 0.543 0.551 0.483#6 Old Mission Dam 60.5 0.696 0.687 54 0.499 0.589 0.745 0.354#7 Mission Ponds 51 0.641 0.604 69.7 0.198 0.162 0.232 0.122DISSOLVED OXYGEN #1 Carlton Hills Blvd. mg/L 5 7.82 7.76 5.6 3.46 3.89 4.4 5.37 5.37#2 Forrestor Creek 7 7.74 8.9 6.9 6.17 5.3 5.02 3.8#4 Sycamore Creek leaving Golf Course 9.1 5.51 6.1 2.53 1.7 2.7 2.31 0.06#5 Mast Boulevard 8.14 7.34 5.71 3.71 5.24 4.9 4.95 4.39#6 Old Mission Dam 6.54 7.78 7.4 5.1 4.35 5.41 6.53 3.21#7 Mission Ponds 5.08 6.71 6.1 5.9 1.64 1.4 1.97 0.97AMMONIA #1 Carlton Hills Blvd. mg/L < .027 < 0.027 < .027 < .04 < .0414 < .0414 < .0414 < .0414#2 Forrestor Creek < .027 < 0.027 < .027 0.052 < .0414 < .0414 < .0414 0.214#4 Sycamore Creek leaving Golf Course < .027 < 0.027 0.169 < .04 < .0414 < .0414 <.0414 < .041#5 Mast Boulevard < .027 < 0.027 < .027 < .04 < .0414 < .0414 <.0414 < .041#6 Old Mission Dam <.027 < 0.027 < .027 0.122 < .0414 <.0414 0.0414 < .041#7 Mission Ponds < .027 <0.027 < .027 < .04 < .0414 <.0414 < .0414 < .041CHLOROPHYLL-A #1 Carlton Hills Blvd. mg/cu. meter N/A N/A 14.8 N/A N/A 0.027 N/A N/A#2 Forrestor Creek N/A N/A 0.593 N/A N/A ND N/A N/A#4 Sycamore Creek leaving Golf Course N/A N/A 2.84 N/A N/A ND N/A N/A#5 Mast Boulevard N/A N/A 1.19 N/A N/A ND N/A N/A#6 Old Mission Dam N/A N/A 2.37 N/A N/A ND N/A N/A#7 Mission Ponds N/A N/A 4.45 N/A N/A ND N/A N/ANITRATE NITROGEN #1 Carlton Hills Blvd. mg/L 10 0.128 0.051 0.529 0.128 0.0692 0.0531 < .017 < .017#2 Forrestor Creek 5.42 4.5 6.18 3.76 2.98 2.09 1.24 1.62#4 Sycamore Creek leaving Golf Course 0.227 0.104 0.957 0.221 0.151 < .0172 < .017 < .017#5 Mast Boulevard 0.584 0.533 0.859 0.643 0.482 0.295 0.233 0.193#6 Old Mission Dam 0.584 0.236 0.747 0.636 0.118 0.0668 0.02 < .017#7 Mission Ponds 0.4 < 0.025 0.701 0.073 0.0306 <.0172 < .017 < .017 Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-96 Table 13-23. Continued. CONSTITUENT SAMPLE POINT Units WQO 5-Jan-2004 2-Feb-2004 1-Mar-2004 5-Apr-2004 3-May-2004 7-Jun-2004 6-Jul-2004 2-Aug-2004NITRITE NITROGEN #1 Carlton Hills Blvd. mg/L 1 < .025 <0.025 < .025 < .02 < .0185 < .0185 < .018 < .018#2 Forrestor Creek < .025 0.191 < .025 0.045 0.232 0.0653 < .018 0.017#4 Sycamore Creek leaving Golf Course < .025 < 0.025 < .025 < .02 < .0185 < .0185 < .018 < .018#5 Mast Boulevard < .025 < .025 < .025 < .02 < .0185 < .0185 < .018 < .018#6 Old Mission Dam < .025 < .025 < .025 < .02 < .0185 < .0185 < .018 <.018#7 Mission Ponds < .025 < 0.025 < .025 <.02 < .0185 < .0185 < .018 < .018ORGANIC NITROGEN #1 Carlton Hills Blvd. mg/L 0.546 0.378 1.41 0.748 0.806 0.747 0.464 0.464#2 Forrestor Creek 1.09 1.44 7.86 4 1.36 1.55 1.72 2.05#4 Sycamore Creek leaving Golf Course 1.34 0.93 2.32 1.34 0.989 0.72 0.81 2.61#5 Mast Boulevard 0.844 1.43 1.79 1.53 1 0.793 0.606 0.678#6 Old Mission Dam 0.844 0.716 1.71 1.55 0.96 0.902 1.25 0.745#7 Mission Ponds 0.949 0.855 1.76 1.35 1.05 0.885 0.805 1.14TOTAL NITROGEN [ AS N ] #1 Carlton Hills Blvd. mg/L 0.674 0.429 1.41 0.748 0.875 0.8 0.464 0.464#2 Forrestor Creek 6.51 5.94 7.86 4.05 4.34 3.64 2.96 3.89#4 Sycamore Creek leaving Golf Course 1.57 0.93 2.49 1.34 1.14 0.72 0.81 2.61#5 Mast Boulevard 1.43 1.43 1.79 1.53 1.48 1.09 0.829 0.871#6 Old Mission Dam 1.43 0.716 1.71 1.68 1.08 0.969 1.27 0.745#7 Mission Ponds 1.35 0.855 1.76 1.35 1.08 0.885 0.805 1.14#1 Carlton Hills Blvd. mg/L 2 <.05 0.028 0.145 0.11 0.075 0.074 0.052 0.052#2 Forrestor Creek 0.07 0.0333 0.134 0.068 < .050 < .050 < .005 0.022#4 Sycamore Creek leaving Golf Course < .050 0.0388 0.132 0.092 0.082 0.094 0.117 0.213#5 Mast Boulevard 0.06 0.033 0.139 0.139 0.11 0.112 0.134 0.149#6 Old Mission Dam 0.11 0.044 0.152 0.152 0.137 0.108 0.157 0.145#7 Mission Ponds 1.98 0.04 0.168 0.104 0.133 0.212 0.184 0.169TOTAL PHOSPHORUS #1 Carlton Hills Blvd. mg/L 2 0.05 0.045 0.189 0.158 0.135 0.132 0.097 0.097#2 Forrestor Creek 0.13 0.092 0.12 0.113 0.04 0.051 0.061 0.079#4 Sycamore Creek leaving Golf Course 0.22 0.108 0.346 0.184 0.146 0.156 0.226 0.375#5 Mast Boulevard 0.15 0.064 0.192 0.194 0.158 0.159 0.198 0.221#6 Old Mission Dam 0.24 0.131 0.211 0.237 0.211 0.207 0.296 0.204#7 Mission Ponds 0.23 0.087 0.263 0.205 0.188 0.267 0.247 0.252E-COLI #1 Carlton Hills Blvd. MPN/100ml 235 10 <10 51 63 10 41 161 161#2 Forrestor Creek 170 148 512 223 121 309 259 644#4 Sycamore Creek leaving Golf Course 2100 31 41 96 246 173 10 20#5 Mast Boulevard 5200 98 63 218 63 233 74 20#6 Old Mission Dam 1400 31 63 318 20 10 1450 31#7 Mission Ponds 810 20 52 31 10 < 10 20 183FECAL COLIFORM #1 Carlton Hills Blvd. MPN/100ml 400 40 500 <200 20 40 40 170 170#2 Forrestor Creek 1700 20 800 300 700 230 500#4 Sycamore Creek leaving Golf Course 170 130 <200 80 300 220 20 20#5 Mast Boulevard 170 20 <200 230 80 700 110 130#6 Old Mission Dam 500 80 200 800 40 20 2200 130#7 Mission Ponds 40 <20 200 40 40 < 20 < 20 270TOTAL COLIFORM #1 Carlton Hills Blvd. MPN/100ml 800 500 400 2400 16,000 9000 3000 3000#2 Forrestor Creek 16,000 500 90,000 5000 9000 9000 16,000#4 Sycamore Creek leaving Golf Course 1100 1400 5000 1100 30,000 2400 9000 1700#5 Mast Boulevard 5000 300 17,000 9000 5000 5000 1300 1700#6 Old Mission Dam 5000 800 1300 2400 9000 9000 9000 1700#7 Mission Ponds 300 80 1300 230 16000 1100 2200 2400ORTHO PHOSPHATE #1 Carlton Hills Blvd. mg/kg N/A N/A 12.9 N/A N/A 0.2 N/A N/A#2 Forrestor Creek N/A N/A 19.3 N/A N/A 0.4 N/A N/A#4 Sycamore Creek leaving Golf Course N/A N/A 1 N/A N/A 0.4 N/A N/A#5 Mast Boulevard N/A N/A 16.6 N/A N/A 0.3 N/A N/A#6 Old Mission Dam N/A N/A 4 N/A N/A 0.7 N/A N/A#7 Mission Ponds N/A N/A 2.7 N/A N/A 0.4 N/A N/ATOTAL PHOSPHORUS #1 Carlton Hills Blvd. mg/kg N/A N/A 21.8 N/A N/A 0.6 N/A N/A#2 Forrestor Creek N/A N/A 37.4 N/A N/A 0.7 N/A N/A#4 Sycamore Creek leaving Golf Course N/A N/A 7 N/A N/A 0.5 N/A N/A#5 Mast Boulevard N/A N/A 18.4 N/A N/A 0.5 N/A N/A#6 Old Mission Dam N/A N/A 11.9 N/A N/A 1.7 N/A N/A#7 Mission Ponds N/A N/A 10 N/A N/A 0.8 N/A N/ASEDIMENTBACTERIAORTHOPHOSPHATE PHOSPHORUS Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-97 Table 13-24. Number of Padre Dam field and analytical samples by station (2004). Padre Dam Station Field Measurements Analytical Measurements Carlton Hills Blvd 8 13 Forrester Creek 8 13 Sycamore Creek leaving Golf Course 8 13 Mast Blvd. 8 13 Old Mission Dam 8 13 Mission Ponds 8 13 13.7.2.2 Padre Dam Data Summary The data collected during the 2004 monitoring effort was compared to the water quality objectives to determine the number of exceedances (Table 13-23), briefly described below. Carlton Hills Boulevard - The site is located at the intersection of the San Diego River and Carlton Hills Boulevard. The station exceeded the WQOs for 4 parameters: the total dissolved solids (TDS) limit was exceeded in 75.0% of the samples; dissolved oxygen was above the WQO in 50% of the samples; while fecal coliform and E. coli each surpassed the WQO in 16.6% of the samples. Forrester Creek – The site is located upstream of the Forrester Creek and the San Diego River convergence. Forrester creek exceeded the WQO for five parameters. TDS had the highest exceedance rate of 91.7%. The fecal coliform and E. coli exceedance rates were 58.0% and 50.0%, respectively. Dissolved oxygen exceeded the acceptable WQO in 25.0% of the samples. Turbidity had the lowest exceedance rate of 8.3%. Sycamore Creek (exiting Golf Course) – The site was sampled were the creek leaves the golf course before the entering the San Diego River. Sycamore creek had values above the WQOs for five parameters. TDS exceeded in 66.7% of the samples. The exceedance rate for dissolved oxygen was 58.3%. Turbidity was above the criteria in 25.0% of the samples. Fecal coliform and E. coli exceeded in 8.3% and 16.7% of the samples, respectively. Mast Boulevard – The site is located at the intersection of Mast Boulevard and the San Diego River. TDS had the greatest number of exceedances, with a rate of 75.0%. Half of the samples exceeded the WQO for dissolved oxygen. A quarter of the samples were above the WQO for E. coli. Fecal coliform exceeded the criteria in 16.7% of the samples. Old Mission Dam – The site is where the dam and river intersect. TDS exceeded in 58.3% of the samples. E. coli exceeded the WQO in 41.7% of the samples. Dissolved oxygen and fecal coliform each exceeded the WOQ in 33.3% of the samples. Turbidity had the least number of WQO exceedances with a rate of only 8.3%. Mission Pond - The site is in one of the five ponds below the Padre Dam. TDS surpassed the action level in 75.0% of the samples. Dissolved oxygen had an exceedance rate of 58.3 %. Turbidity exceeded the WQO in 25% of the samples. Fecal coliform and E. coli had exceedance rates of 8.3% and 16.7%, respectively. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-98 13.7.3 Third Party Data Conclusions Third party data collected in 2002 in the Carlsbad watershed found that there were water quality objective exceedances for sulfate, manganese and toxicity at the station located on Agua Hedionda Creek upstream of the MLS. Two sampling locations were located on Escondido Creek, one upstream of the MLS and one located in the same vicinity as the MLS. There were water quality objective exceedances for pH, sulfate, manganese, Diazinon and toxicity at both stations. In Los Peñasquitos watershed, the station located on Los Peñasquitos Creek in the same vicinity as the mass loading station, had water quality objective exceedances for turbidity, pH, sulfate, Diazinon, methyl parathion and toxicity. Exceedances observed at the other two stations within Los Peñasquitos watershed were similar to exceedances that were found in Los Peñasquitos Creek. Sulfate, manganese and toxicity consistently exceeded objectives at all sites and turbidity and Diazinon concentrations exceeded objectives sporadically. There were two sampling sites within the Mission Bay watershed, one located on Tecolote Creek near the mass loading station and one located on Rose Canyon Creek. There were water quality objective exceedances for sulfate, manganese and toxicity at the Tecolote Creek station. Exceedances observed at Rose Canyon Creek included sulfate, manganese, turbidity, pH, Diazinon and toxicity. The 2004 Padre Dam data provides some additional information for the water quality assessment of the San Diego River WMA. Exceedances were noted for dissolved oxygen (33), turbidity (8), E. coli (20), fecal coliform (17), and TDS (53). The most notable result was the 91.7% exceedance rate (11 exceedances out of 12 samples) for TDS in Forrester Creek. In addition, all six stations exceeded the WQO for fecal coliform in the month of December, and five stations also exceeded the WQO for E. coli. 13.8 Regional Water Quality Priority Rating The preceding subsections presented on a regional basis the results and conclusions of the wet weather mass loading station monitoring program, the dry weather investigations, stream bioassessment studies, Ambient Bay and Lagoon monitoring, coastal outfall monitoring and third party data investigations. This sub-section utilizes these monitoring data to assess on a watershed basis the regional water quality priorities. A methodology for developing water quality priority ratings to assess long-term effectiveness was developed as part of the Baseline Long-Term Effectiveness Assessment (BLTEA) (WESTON, MOE & LWA 2005). This rating system is presented to supplement the previously reported scores by integrating the results of wet weather monitoring, dry weather investigations, ABLM, and bioassessment results, and therefore providing an overall regional assessment regarding the water quality priorities in the County. The San Diego Municipal Stormwater Permit NPDES Order No. 2001-01 (Permit) requires that the Copermittees develop and implement a broad array of Jurisdictional Urban Runoff Management Program (JURMP) activities, and that the long-term effectiveness of implementing these program activities be periodically assessed. In October 2003, the Copermittees published a collaboration of efforts developed to address long-term effectiveness assessment strategies entitled, “A Framework for Assessing the Effectiveness of Jurisdictional Urban Runoff Management Programs”. The current water quality and source data that have been collected by the Copermittees provide a strong basis for the development and establishment of the Long-Term Effectiveness Process. From this solid foundation, the framework first developed by the Copermittees in the October 2003 document was further developed and enhanced in the Baseline Long-Term Effectiveness Assessment report to allow for this process to move forward. The BLTEA report established a prioritization of program efforts through the integration of water quality data to the loading potential of sources on a watershed basis. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-99 The water quality priority ratings presented in this sub-section are based on the methodology presented in BLTEA report and the following data sets including the current results presented in this 2004/2005 annual report: • Storm water Mass Loading Monitoring (MLS) – Wet Weather Data • Copermittee Dry Weather Data Monitoring • Ambient Bay, Lagoon, and Coastal Receiving Water Monitoring (ABLM) • Urban Stream Bioassessment Monitoring • Triad Assessment – Toxicity Testing of Storm water • 303(d) Listing Coastal storm drain outfall monitoring is not included in the rating development, because the outfalls are not monitored for specific sub-watersheds, but rather they are monitored for small, specific catchments associated with the corresponding outfall pipe. Different from the scoring system presented in the Watershed Management Assessment sections, the 303(d) listing for each defined section of the receiving waters in the County is used in the determination of the water quality score on a sub-watershed basis. If a sub-watershed has a section of the receiving waters 303(d) listed, then the rating was given the highest priority. This use of the 303(d) list to override the water quality results is used in this process not to question the existing data, but to identify a high priority to assess trends in water quality within this sub-watershed and identification of high loading potential sources based on the overall threat to water quality assigned to the watershed and sources located within the sub-watershed. The criteria used to compare the water quality data included frequency of exceedances of water quality objectives or action levels and measured biological effects. The overall watershed priority rating was then determined using the sub-watershed ratings that were weighted based on the aerial percent of each watershed. Therefore, the watershed water quality rating is a weighted average that represents the water quality priorities for the entire watershed. Because the ratings are a weighted average, watershed ratings may not indicate specific water quality issues within individual sub-watersheds. The rating system developed in the BLTEA includes ratings on sub-watershed levels, and these should be reviewed to determine water quality issues within the watershed. The specific methodology and criteria used are specified in the BLTEA report (WESTON, MOE & LWA 2005). A summary of the water quality rating method is presented in Section 3.4. Water quality priority ratings are developed for the constituent groups: • Heavy Metals • Organics • Oil and Grease • Sediment (TSS, SS, Turbidity) • Pesticides • Nutrients • Gross Pollutants • Bacteria/Pathogens The Water Quality Priority Rating for these eight constituent groups is determined using the available data set as summarized above. The additional evaluated stressor groups include benthic alteration and toxicity. These last two groups are evaluated separately as they represent a stressor group that may be impacted by multiple constituents and/or stressors, as compared to the other groups that represent Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-100 specific constituents. The basis for the water quality ratings for the toxicity stressor group include the toxicity testing results from the wet weather sampling at the MLS and the sediment sampling conducted as part of the ABLM program. The benthic alteration stressor group rating is based on the results of the regional bioassessment conducted during wet weather conditions, and the ABLM benthic community structure results conducted on sediment samples. These data are then used to develop the prioritization ratings that are based on a score of 0 – 3. From the numerical score, a prioritization rating is then assigned. The highest priority rating is A, followed by a rating of B, C, and D. D therefore represents a low priority rating or insufficient data to support a higher rating. These priority ratings provide a defined water quality characterization and prioritization that can be used to compare with source data in establishing an overall threat to water quality for each constituent group on a watershed basis. The Watershed Water Quality Priority Ratings are shown graphically on Figures 13-52 through 13-61 for each of the constituent groups (heavy metals, organics, oil & grease, sediments, pesticides, nutrients, gross pollutants, and bacteria, respectively). The figures provide a regional assessment on a watershed basis of the water quality priorities. Also shown on these maps are the sampling locations (wet and dry weather samples) from which data has been collected and used in this assessment. The data tables used in support of these figures is presented in Appendix G. The overall regional conclusions based on the water quality ratings as presented on Figure 13-52 to 13-61 can be summarized as follows: • Heavy Metals (Figure 13-52) – The highest rated watershed for metals is the Mission Bay WMA. This is for the most part due to two of the three sub-watersheds in this WMA having section on 303(d) list for metals. The other watershed ratings are predominantly of medium priority. The watershed rating reflects the overall watershed priority based on the weighted average score of all the sub-watersheds. Therefore, there may be WMA that contain one or two sub-watersheds that have high priority ratings, but due to their size in comparison to the other lower scored sub- watersheds, results in a lower overall watershed rating. This is the case for San Diego Bay WMA and Tijuana WMA. Figure 13-53 presents the priority rating on a sub-watershed basis for San Diego Bay WMA. As shown on Figure 13-53, there are several sub-watersheds within this WMA with an A (highest) rating, although the overall watershed rating is C due the smaller size of these A rate sub-watersheds out of the nine within this WMA. The Tijuana WMA also contained one high rated sub-watershed at the base of the watershed (Tijuana Valley). The lower ratings for the other sub-watersheds are also due in part to limited data on a sub-watershed basis (no dry weather or wet weather results are available for these other sub-watersheds). These results show the importance of evaluating the water quality priorities to a sub-watershed level, and the need to obtain additional data on a sub-watershed basis. These data issues are addressed in the recommended monitoring program modifications presented in Section 14. • Organics (Figure 13-54) – All the WMAs were rated the lowest priority of D for organic constituents based on the available data. Only the San Diego Mesa sub-watershed in the San Diego Bay WMA and the Tijuana Valley sub-watershed in the Tijuana WMA were rated A based on inclusion on the 303(d) list. Organics are not monitored as part of the dry weather sampling program. Therefore, the current data set on a sub-watershed basis is limited. The overall ratings are therefore currently based on 303(d) listing and wet weather data from the MLS and sediment data from the ABLM program projected up into the watershed. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-101 Figure 13-52. Watershed Water Quality Priority Rating for Heavy Metals. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-102 Figure 13-53. Sub-Watershed Water Quality Priority Rating for San Diego Bay WMA - Heavy Metals. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-103 Figure 13-54. Watershed Water Quality Priority Rating for Organics. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-104 • Oil and Grease (Figure 13-55) - All the WMAs were rated the lowest priority of D for oil and grease based on the available data. Within these WMAs, the highest sub-watershed ratings were determined for the Lower San Diego sub-watershed in the San Diego River WMA and the National City sub-watershed in the San Diego Bay WMA. • Sediment (Figure 13-56) – Regionally, high sediment ratings were scored for all the WMA. The highest rated WMA, with an A rating, included the Santa Margarita, San Luis Rey, Carlsbad, San Dieguito, Los Peñasquitos, San Diego River, and San Diego Bay WMAs. The remaining two WMAs, the Tijuana and Mission Bay WMA had a rating of B. As mentioned previously, the watershed rating reflects the overall watershed priority based on the weighted average score of all the sub-watersheds. Therefore, there may be WMAs that contain one or two sub-watersheds that have high priority ratings, but due to their size in comparison to the other lower scored sub- watersheds, result in a lower overall watershed rating. This is the case for the Tijuana WMA. The Tijuana WMA contains one high rated sub-watershed at the base of the watershed (Tijuana Valley). The lower ratings for the other sub-watersheds are due in part to limited data on a sub- watershed basis (no dry weather or wet weather results are available for these other sub- watersheds). These results show the importance of evaluating the water quality priorities to a sub-watershed level, and also the potential data gaps in the data set. Sediment data (TSS, SS, turbidity, etc.) are not monitored as part of the dry weather sampling program or a parameter that can be related to sediment results. Therefore, the current data set on a sub-watershed basis is limited. The overall ratings are therefore currently based on 303(d) listing and wet weather data from the MLS projected up into the watershed. These results reflect the need to better integrate the wet and dry weather programs to better assess the regional water quality priorities. This issue is addressed in the recommended monitoring program recommendations presented in Section 14. • Pesticides (Figure 13-57) – The highest rated WMA include the San Diego River and San Diego Bay WMAs. The remaining watersheds have a lower priority with ratings of C and D. Only the San Diego Mesa sub-watershed in the San Diego Bay WMA and the Tijuana Valley sub-watershed in the Tijuana WMA were rated the highest based on inclusion on the 303(d) list for pesticides. • Nutrients - (Figure 13-58) – The highest rated WMAs include the Carlsbad, Santa Margarita, Mission Bay, and Tijuana, with a priority rating of B. All other WMAs had a priority rating of C, with the exception of Peñasquitos which had a priority rating of D. The high rating of B in most of the WMAs are due to several sub-watersheds within these WMA that have sections of the receiving waters on the 303(d) list for nutrients. • Gross Pollutants – (Figure 13-59) – The higher ratings for several of the WMAs are due predominantly to 303(d) listings in specific sub-watersheds, with the exception of the Tijuana and Santa Margarita WMAs that are also based on the results of the wet weather monitoring. Gross pollutants are not monitored as part of the dry weather sampling program or sediment results. Therefore, the current data set on a sub-watershed basis is limited. The overall ratings are therefore currently based on 303(d) listing and wet weather data from the MLS data projected up into the watershed. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-105 Figure 13-55. Watershed Water Quality Priority Rating for Oil and Grease. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-106 Figure 13-56. Watershed Water Quality Priority Rating for Sediment. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-107 Figure 13-57. Watershed Water Quality Priority Rating for Pesticides. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-108 Figure 13-58. Watershed Water Quality Priority Rating for Nutrients. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-109 Figure 13-59. Watershed Water Quality Priority Rating for Gross Pollutants. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-110 • Bacteria/Pathogens – (Figure 13-60) – As shown on Figure 13-60, bacteria is a high priority regionally. The highest priority rating of A was determined for five of the nine WMAs, including the San Luis Rey, Carlsbad, Peñasquitos, Mission Bay and San Diego River WMAs. The remaining four watersheds received a priority rating of B. These results are consistent with the overall current understanding of water quality summarized in the previous sub-sections. As stated previously, the watershed rating reflects the overall watershed priority based on the weighted average score of all the sub-watersheds. Therefore, there may be WMAs that contain one or two sub-watersheds that have high priority ratings, but due to their size in comparison to the other lower scored sub-watersheds, results in a lower overall watershed rating. This is the case for the Santa Margarita and Tijuana WMAs. Figure 13-61 presents the priority rating for bacteria on a sub-watershed basis for the Tijuana WMA. As shown on Figure 13-61, the Tijuana WMA also contains one high rated sub-watershed at the base of the watershed (Tijuana Valley). The lower ratings for the other sub-watersheds are also due in part to limited data on a sub- watershed basis (no dry weather or wet weather results are available for these other sub- watersheds). These results show the importance of evaluating the water quality priorities to a sub-watershed level, and the potential data gaps on a sub-watershed basis. These results reflect the need to better integrate the wet and dry weather programs to better assess the regional water quality priorities. This issue is addressed in the recommended monitoring program recommendations presented in Section 14. The results of the Water Quality Assessment using the priority rating system indicate consistency with the current understanding of water quality conditions in the County as summarized in the previous sub- section. The consistent water quality problems that are indicated by the determined priority ratings in the region are the bacteria and sediment (TSS, turbidity, SS, etc.) constituent groups. The results of the water quality ratings for benthic alterations and toxicity are also consistent with previously summarized conclusions in this section. Regionally, benthic alterations are rated a high priority (generally a B rating), which are consistent with the generally poor to very poor IBI scores for regional bioassessment sites. The regional ratings for toxicity are also consistent in that they reflect water quality issues at the lower portion of the Tijuana WMA and 303(d) listed sections in the San Diego Bay WMA. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-111 Figure 13-60. Watershed Water Quality Priority Rating for Bacteria/Pathogens. Regional Assessments SECTION 13 2004-2005 Urban Runoff Monitoring Report 13-112 Figure 13-61. Sub-Watershed Water Quality Priority Rating for Tijuana WMA – Bacteria. Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-1 14.0 CONCLUSIONS AND RECOMMENDATIONS 14.1 Conclusions 14.1.1 Wet Weather Monitoring Conclusions The current monitoring program has allowed the region to gain an understanding of wet weather conditions at the base of watersheds throughout the County. It has provided both long-term trend analyses at historic stations, and the foundation for long-term trends throughout the County. TIEs conducted during wet weather events at stations with persistent exceedances of toxicity have identified causes of toxicity in the Tijuana River. A comparison between watersheds has determined that the Tijuana River and Chollas Creek consistently have more wet weather water quality objective exceedances than other watersheds in the County. The results for Agua Hedionda Creek have indicated increasing long-term trends for a number of constituents that appear to be related to greater sediment loads and increasing nutrients in wet weather flows. From a regional perspective, the consistent wet weather water quality issues in the region include coliform bacteria, total suspended solids, and turbidity. Table 14-1 shows persistent wet weather constituents of concern and statistically significant trends observed for each mass loading station. The single event and annual mean concentrations for key constituents and toxicity at the Tijuana River MLS were statistically different and concentrations and magnitude of exceedances of WQO were significantly higher compared to all the other MLS, particularly those associated with untreated wastewater and highly urbanized land use, including fecal coliform bacteria, TSS, metals, pesticides, and nutrients. This is a pattern that has been consistent throughout the past four years of monitoring. This MLS has also had the most consistent toxicity results with toxicity to Ceriodaphnia and Hyalella. On a regional basis, TSS annual mean concentrations have exceeded the WQO in 7 of the 11 MLS over the last 4 monitoring years indicating that TSS, which is an indicator of sediment loading, is a regional water quality issue. Higher TSS can be associated with an increase in land disturbance activities in the watershed, and increased impervious areas upstream of creek and river sections that may be subject to bank erosion from greater and more sustained peak flows. Temporal patterns in TSS concentrations indicate higher concentrations during greater intensity storm events. Across watersheds, the highest exceedances were observed for the 2004-2005 monitoring period which corresponds to the year of greatest precipitation. Larger and greater intensity storm events will mobilize a greater amount of sediment that would then correlate to greater TSS concentrations. As presented in Table 14-1, long- term significant trends include increasing turbidity and TSS in Agua Hedionda Creek and increasing turbidity in Chollas Creek. Turbidity and TSS concentrations at these MLS were above the WQO. Regionally, the concentration of fecal coliform has exceeded the WQO in all watersheds in multiple years. The highest exceedances occurred at the Tijuana River, which has multiple water quality issues likely associated with the reported discharges of untreated sewage. Bacteria appears to be a consistent regional water quality issue. As summarized in Table 14-1, notable long-term trends for bacteriological indicators demonstrate increasing trends for enterococci in Tecolote Creek, the San Luis Rey River, and the Tijuana River, and for fecal coliform in the San Luis Rey River and Agua Hedionda Creek. Concentrations of fecal coliform were generally above the WQO. Concentrations of indicator bacteria in the San Luis Rey River have increased from below to above the WQO. Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-2 Table 14-1. Mass Loading Station Persistent Wet Weather Constituents and Trends. Mass Loading Station Persistent Wet Weather Constituents of Concern Significant Trends Observed Santa Margarita Fecal Coliform Turbidity No observed trends San Luis Rey Total Dissolved Solids Increasing nitrate, total coliform, fecal coliform, and enterococcus Agua Hedionda Creek Fecal Coliform Total Suspended Solids Turbidity Enterococcus Increasing chemical oxygen demand, total Kjeldahl nitrogen, total and dissolved phosphorus, total suspended solids, turbidity, fecal coliform, and total lead Decreasing conductivity Escondido Creek Fecal Coliform Total Coliform Total Dissolved Solids Turbidity Increasing pH Decreasing Diazinon San Dieguito River Total Dissolved Solids Increasing nitrate and total and dissolved phosphorus Decreasing total chromium Peñasquitos Creek Total Dissolved Solids Decreasing Diazinon Tecolote Creek Fecal Coliform Total Coliform Enterococcus Turbidity Increasing total phosphorus and enterococcus Decreasing MBAS, ammonia as N, Diazinon, total cadmium and lead San Diego River Fecal Coliform Total Coliform Enterococcus Turbidity Decreasing conductivity and Diazinon Chollas Creek Fecal Coliform Total Coliform Enterococcus Turbidity Diazinon Total and Dissolved Copper Total Zinc Increasing turbidity and nitrite Decreasing total lead Sweetwater River Fecal Coliform Decreasing Diazinon Tijuana River Fecal Coliform Total Coliform Enterococcus Total Suspended Solids Turbidity Diazinon Increasing total suspended solids and enterococcus Decreasing total dissolved solids, conductivity, dissolved arsenic and nickel Additional notable trends based on regression analysis and listed in Table 14-1 include: • Nutrients - Increasing nitrate concentration in the San Luis Rey and San Dieguito Rivers. Increasing total and dissolved phosphorus concentrations in Agua Hedionda Creek and the San Dieguito River, total phosphorus in Tecolote Creek, and nitrite in Chollas Creek. Concentrations of nitrate and dissolved phosphorus are below the WQO. Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-3 • Pesticides - Diazinon concentrations indicate significant decreasing trends in Escondido Creek, Peñasquitos Creek, Tecolote Creek, the San Diego River, and Sweetwater River. Concentrations have decreased from above to below the WQO. • Metals - Trend analysis based on regression analysis of the wet-weather data indicate a significant increasing trend for total lead in Agua Hedionda Creek. Decreasing trends are noted for total lead concentrations in Tecolote Creek and Chollas Creek; for total chromium in the San Dieguito River; for total cadmium in Tecolote Creek, and for dissolved arsenic and nickel in the Tijuana River. Relationships between Ceriodaphnia dubia toxicity and COC based on the four years of data showed strong relationships for increasing toxicity with higher amounts of Diazinon, dissolved phosphorus, and dissolved nickel. Strong relationships based on the threshold analysis were also found for Diazinon. 14.1.2 Stream Bioassessment Conclusions A total of 27 different stream monitoring reaches were assessed in San Diego County in October 2004 and May 2005. Four of these sites represented reference conditions. A total of 49 different monitoring reaches have been sampled since May 2001. Taxonomic identification of samples collected in October 2004 produced 110 taxa from a total of 18,460 individuals. The May 2005 samples produced 91 taxa from 21,534 individuals. The most abundant organisms in October 2004 in the study region were Simulium (Diptera: Simuliidae), non-biting midges (Diptera: Chironomidae), Hyalella (Amphipoda: Hyalellidae) and Ostracods (Ostracoda). The most abundant organisms in May 2005 in the study region were Simulium (Diptera: Simuliidae), Baetis (Ephemeroptera: Baetidae), and non-biting midges (Diptera: Chironomidae). The majority of organisms from the urban affected sites were moderately or highly tolerant to stream impairments. Organisms highly intolerant to impairments were encountered infrequently at the urban affected sites, but their presence even in low numbers is significant. Non-reference sites that supported highly intolerant organisms included San Dieguito River-Del Dios Highway and Santa Margarita River- Willow Glen Road. The Index of Biotic Integrity ratings of the monitoring sites ranged from Very Good to Very Poor in both surveys. IBI scores for the reference sites were always higher than the scores for the urban influenced sites, although REF-SC2 was one point higher than the highest non-reference site in the May 2005 survey. The May 2005 survey produced consistently lower IBI scores across the entire region than the October 2004 survey. Comparison of IBI scores with the in-stream physical habitat quality of the monitoring reaches indicated a poor correlation between habitat quality and benthic macroinvertebrate community quality. Of all of the watersheds in San Diego County, the Santa Margarita River watershed had the least impaired benthic macroinvertebrate communities. The remaining watersheds have substantially greater amounts of urbanization, and the IBI results generally indicate that increased water quality impairment occurs in the lower portions of the watersheds, as the impacts of urban runoff become cumulative. After 4½ years of bioassessment surveys, the most significant observation is that the macroinvertebrate community quality has not shown any trend towards degradation or improvement. IBI scores for most of Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-4 the San Diego sites were similar between May 2001 to May 2005. Individual seasons or years have produced varying conditions for the macroinvertebrates, and many of the monitoring sites have shown a parallel response to the variability of the conditions. 14.1.3 Ambient Bay and Lagoon Program Conclusions In the summer of 2004 sediments in the twelve major coastal embayments in San Diego County were monitored to assess the potential for adverse effects from the watershed and to compare sediment quality among the embayments. In Phase I, a stratified random approach was used to identify the three sites in each embayment where COC were most likely to be found (i.e., those with the highest TOC and smallest grains size). Buena Vista Lagoon had a much higher percentage of TOC and fine grained sediments than the other embayments. In contrast, sediments in Santa Margarita River Estuary contained a much lower TOC content and percentage of fine-grained particles than the other embayments. This pattern was also seen in the 2003 ABLM sampling. In Phase II of the assessment, the three sites identified in Phase I for each embayment were sampled and analyzed for chemistry, toxicity, and benthic community structure. For the chemistry assessment, composite sediment samples from each embayment were analyzed for metals, PCBs, PAHs, and pesticides. PCBs, PAHs, and pesticides were not detected in any of the embayments. A suite of six metals was found in all 12 embayments: arsenic, chromium, copper, lead, nickel, and zinc. In general, concentrations of metals were low in all embayments and there were no metals that exceeded their ERM thresholds. However, several metals exceeded ERL values, including copper (exceeded the ERL at three sites), arsenic (exceeded the ERL at four sites), zinc (exceeded the ERL at three sites), and lead (exceeded the ERL at one site). The mean ERM-Q value, which represents the cumulative impact from all COCs for which ERMs are available, was greatest at Mission Bay and Oceanside Harbor and lowest at the Santa Margarita River Estuary and San Elijo Lagoon. For the toxicity assessment, the percent survival of a marine amphipod exposed to sediments from each of the embayments was compared to that of a control. Percent survival was not significantly different from that of the control for ten embayments: Santa Margarita River Estuary, Oceanside Harbor, San Luis Rey River Estuary, Buena Vista Lagoon, Agua Hedionda Lagoon, San Elijo Lagoon, Los Peñasquitos Lagoon, Mission Bay, Sweetwater River Estuary, and Tijuana River Estuary. The two remaining embayments where percent survival was significantly different from that of the control were Batiquitos Lagoon and San Dieguito Lagoon. For the benthic community assessment, animals collected from the sediment at three sites in each embayment were identified to the lowest possible taxonomic level. Several indices of benthic community structure were then calculated, including abundance, richness, diversity, evenness, and dominance. For each embayment the scores from these indices were ranked and the summed ranks were used to compare the benthic communities among the 12 embayments. Based on this overall ranking, the embayments with the best relative benthic communities were Mission Bay, Sweetwater River Estuary, Batiquitos Lagoon, Oceanside Harbor, Santa Margarita River Estuary, and San Dieguito Lagoon. Those with the worst relative benthic communities were Buena Vista Lagoon, Agua Hedionda Lagoon, Los Peñasquitos Lagoon, Tijuana River Estuary, San Luis Rey River Estuary, and San Elijo Lagoon. The experimental design for the ABLM Program was based on a presumed positive correlation between COCs, TOC content, and grain size, where higher COC concentrations are expected in areas with higher TOC and smaller grain size. However, the relationships between sediment chemistry, toxicity, Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-5 and benthic community structure were weak for the 2004 data set. This is likely due to the dynamic nature of coastal estuaries and a limited number of samples and analyses. Results from samples collected in subsequent years of the ABLM Program may help to strengthen these relationships. 14.1.4 Watershed Assessment Conclusions 14.1.4.1 Santa Margarita River Watershed Management Area The Santa Margarita River watershed is the second largest in the San Diego hydrologic region. The primary land use within the contributing runoff area is undeveloped (64%). For the Santa Margarita River WMA, turbidity and fecal coliform were identified as high frequency of occurrence COC, TSS was identified as a medium frequency of occurrence COC, and TDS and nitrate were identified as low frequency of occurrence COC. There was no evidence of persistent toxicity found in Santa Margarita River. The stream habitat quality varied between poor and fair which indicated that there was no evidence of benthic alteration. Based on the Ambient Bay and Lagoon Monitoring Program, the relative ranks for the Santa Margarita River Estuary were one for chemistry, two for toxicity and five for benthos. Compared to the other embayments in the 2004 ABLM program, the Santa Margarita River Estuary had an overall rank of one. The relative ranks for Oceanside Harbor were 10 for chemistry, 6 for toxicity, and 2 for benthos. The benthic community ranked second highest among other embayments within San Diego County. Compared to the other embayments in the 2004 ABLM program, Oceanside Harbor had an overall rank of six. The relative quality for both the Santa Margarita River Estuary and Oceanside Harbor increased from the ABLM 2003 monitoring year. The WMA assessment findings agreed with the BLTEA rating priorities for the Santa Margarita River WMA, which found sediments to be a high priority (A rating) constituent. The BLTEA ratings also gave a B rating to nutrients, bacteria, gross pollutants and benthic alteration. 14.1.4.2 San Luis Rey River Watershed Management Area The San Luis Rey River watershed is the third largest watershed in San Diego County. The contributing runoff area is representative of the entire watershed which is approximately 29% open space and 25% agricultural. For the San Luis Rey River WMA, TDS was the only high frequency of occurrence COC, followed by turbidity, nitrate, ammonia, and all three bacterial indicators which were all low frequency of occurrence COC. There was no evidence of persistent toxicity in San Luis Rey River, however, the benthic community appeared to be limited by unknown factors. While high TDS levels may be affecting diversity, there may be other constituents not measured that are impacting the benthic invertebrate community. In the San Luis Rey River Estuary, the final receiving waters for the San Luis Rey River, relative rankings were five for sediment chemistry, four for toxicity and eight for the benthic community. The San Luis Rey River Estuary was rated intermediate compared against other embayments within San Diego County. Compared to last year’s ranking, the San Luis Rey River Estuary experienced a decrease in relative quality. In addition to the WMA assessment findings, the BLTEA findings suggest that sediments and bacteria are also high priority (A rated) constituents followed by benthic alteration which was given a B rating. 14.1.4.3 Carlsbad Watershed Management Area The Carlsbad watershed is the third most densely populated watershed in the San Diego region. For the Agua Hedionda sub-watershed which accounts for 11% of the Carlsbad watershed, land use within the contributing runoff area is primarily residential (33%), undeveloped (25%), and agriculture (11%). For Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-6 Agua Hedionda Creek, TSS, turbidity, fecal coliform, and enterococcus were identified as high frequency of occurrence COC, TDS and diazinon were identified as medium frequency of occurrence COC, and pH, COD, ammonia, and total coliform were identified as low frequency of occurrence COC. For the Escondido Creek sub-watershed which accounts for approximately 33% of the Carlsbad watershed, land use within the contributing runoff area is predominantly undeveloped (35%), residential (25%), and parks (16%). For Escondido Creek, TDS, turbidity, total coliform, and fecal coliform were identified as high frequency of occurrence COC, enterococcus was identified as a medium frequency of occurrence COC, and TSS and nitrate were identified as low frequency of occurrence COC. In Agua Hedionda Creek, increasing trends were observed for fecal coliform, TSS, turbidity, COD, TKN, total and dissolved phosphorus, and total lead. Third party data collected in 2002 under SWAMP, indicated that sulfate, manganese, and toxicity were consistent problems throughout the Carlsbad watershed. The sources of the water quality problems in the watershed are unknown but likely come from several disperse sources. The water quality concerns were highlighted by poor and very poor ratings of the macroinvertebrate communities in the streams. Four lagoons within the Carlsbad watershed were monitored in the Ambient Bay and Lagoon Monitoring Program, including Buena Vista, Agua Hedionda, Batiquitos, and San Elijo Lagoons. For Buena Vista Lagoon, the relative ranks were nine for chemistry, one for toxicity, and nine for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Buena Vista Lagoon had an overall rank of seven. The relative ranks for Agua Hedionda Lagoon were five for chemistry, seven for toxicity, and six for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Agua Hedionda Lagoon had an overall rank of six. For Batiquitos Lagoon, the relative ranks were 6 for chemistry, 10 for toxicity, and 2 for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Batiquitos Lagoon had an overall rank of six. For San Elijo Lagoon, the relative ranks were two for chemistry, five for toxicity, and seven for benthic community structure. Compared to the other embayments in the 2004 ABLM program, San Elijo Lagoon had an overall rank of three. The relative quality in all lagoons within the Carlsbad watershed increased compared to the 2003 ABLM rankings. The WMA assessment findings agreed with the BLTEA rating priorities, which found sediments and bacteria to be high priority (A rating) constituents followed by nutrients and benthic alteration which were given a B rating. 14.1.4.4 San Dieguito River Watershed Management Area The San Dieguito River MLS run-off area accounts for only 8% of the overall San Dieguito WMA. Approximately 86% of the watershed lies behind dams (Coastal Conservancy 2001). The major land uses within the contributing runoff area are undeveloped (24%), parks (24%), residential (21%), and agricultural (18%). For the San Dieguito River, only TDS was identified as a high frequency of occurrence COC, fecal coliform was identified as a medium frequency of occurrence COC, and turbidity, total coliform, and enterococcus were identified as low frequency of occurrence COC. The in-stream benthic community appears to be limited by unknown factors, and while high TDS levels may be affecting diversity, there may be other constituents not measured that are impacting the benthic community. In San Dieguito Lagoon, the relative rankings were 3 for chemistry, 10 for toxicity, and 4 for benthic community structure. Overall, the San Dieguito Lagoon was rated intermediate compared to other embayments within San Diego County. San Dieguito Lagoon experienced a decrease in relative quality compared to the 2003 ABLM program. Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-7 In addition to the WMA assessment findings, the BLTEA ratings found sediments as a high priority (A) rating followed by gross pollutants, bacteria, benthic alteration, and toxicity which were given a B rating. 14.1.4.5 Los Peñasquitos Creek Watershed Management Area The Los Peñasquitos Creek run-off area accounts for approximately 60% of the Los Peñasquitos watershed management area. The major land uses within the contributing runoff area are parks (29%), residential (28%), and undeveloped (24%). For the Los Peñasquitos Creek WMA, only TDS was identified as a high frequency of occurrence COC, fecal coliform was identified as a medium frequency of occurrence COC, and turbidity, ammonia, orthophosphate, total coliform, and enterococcus were identified as low frequency of occurrence COC. Third party data collected in 2002 under SWAMP indicated that sulfate, manganese, and toxicity were consistent problems throughout Los Peñasquitos watershed. The in-stream benthic community appears to be limited by unknown factors, and while high TDS levels may be enough of a stress to insects, other constituents not monitored in the Los Peñasquitos Creek MLS watershed may also be affecting the benthic invertebrate community. In Los Peñasquitos Lagoon, the final receiving waters for Los Peñasquitos Creek, relative rankings were four for chemistry, three for toxicity, and six for benthic community structure. Compared to the other embayments in the 2004 ABLM program, Los Peñasquitos Lagoon had an overall rank of two. The relative quality within the lagoon increased compared to the 2003 ranking. In addition to the WMA assessment findings, the BLTEA ratings found sediments and bacteria to be the highest priority (A rated) constituents for the Los Peñasquitos WMA followed by benthic alteration which was given a B rating. 14.1.4.6 Mission Bay Watershed Management Area For the Tecolote Creek sub-watershed, which accounts for approximately 14% of the Mission Bay watershed management area, the primary land uses within the contributing runoff area are residential (43%) and transportation (21%). For the Mission Bay WMA, turbidity and all three bacterial indicators were identified as high frequency of occurrence COC, TSS and Diazinon were identified as medium frequency of occurrence COC, and ph, COD, and orthophosphate were identified as low frequency of occurrence COC. Third party data collected in 2002 under SWAMP indicated that sulfate, manganese, and toxicity were consistent problems at the Tecolote Creek monitoring station. There was no evidence of persistent toxicity associated with samples collected from the Tecolote Creek MLS. However, the in- stream benthic community was ranked as poor and very poor, suggesting evidence of benthic alteration. In Mission Bay, the final receiving waters for Tecolote Creek, relative rankings were 11 for chemistry, 8 for toxicity and 1 for benthic community structure. Overall, Mission Bay received a ranking of eight compared to other embayments within San Diego County. Mission Bay experienced a decrease in relative quality compared with the 2003 ABLM program. In addition to the WMA assessment findings, the BLTEA ratings found heavy metals and bacteria were the highest priority (A rated) constituents for the Mission Bay WMA followed by sediments, nutrients, and bacteria which were given B ratings. The heavy metals priority rating found in the BLTEA rating was primarily due to the 303(d) listings for metals in the Miramar and Tecolote sub-watersheds even though the WMA assessment did not indicate metals were an overall priority 14.1.4.7 San Diego River Watershed Management Area The San Diego River watershed is the second largest watershed in San Diego County. The contributing runoff area to the MLS is approximately 39% of the San Diego watershed land area. The major land uses Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-8 within the contributing runoff area are residential (29%), parks (24%), and undeveloped (21%). For the San Diego River WMA, turbidity and all three bacterial indicators were identified as high frequency of occurrence COC followed by TDS, which was identified as a medium frequency of occurrence COC. TDS during wet weather monitoring and monthly monitoring within the watershed by Padre Dam showed a medium frequency of occurrence but appears to be related to groundwater influences and local conditions. As noted in Section 10.2.3, the TDS water quality objective may not accurately reflect the natural conditions of the San Diego River WMA. Dissolved oxygen in samples collected by Padre Dam exceeded the Basin Plan water quality objective 46% of the time. Although ammonia and orthophosphate in dry weather data may indicate localized issues within the WMA, the evaluation and combination of Padre Dam data in the assessment process suggests that on a regional scale these constituents do not frequently exceed water quality objectives. The occurrence of these constituents may be a result of numerous activities or sources. The stream habitat quality was rated Poor in Mission Trails, a large open recreation space, and Very Poor in Mission Valley, a highly urbanized residential and commercial corridor. The Very Poor rating in Mission Valley may be a result of physical disturbances to habitat, insecticides or other COC that are not analyzed for in this program, or algal growth observed and measured as chlorophyll within the stream. In addition to the WMA assessment findings, the BLTEA ratings found sediments, bacteria, and benthic alteration were the highest priority (A rated) constituents for the San Diego River WMA followed by pesticides which was given a B rating. 14.1.4.8 San Diego Bay Watershed Management Area The Chollas sub-watershed within the Pueblo San Diego watershed drains a very densely populated, urban area. Nearly 65% of the drainage area is residential and another 17% is commercial. Turbidity, all three indicator bacteria, Diazinon, total and dissolved copper, and total zinc were identified as high frequency of occurrence COC. Medium frequency of occurrence COC were identified for COD, and TSS, followed by BOD, MBAS, ammonia, orthophosphate, and total lead which were identified as low frequency of occurrence COC. The benthic community impacts and stream habitat impairments may be a result of elevated COC or physical alterations to the riparian corridor. Since the EPA has banned the retail sale of Diazinon and Chlorpyrifos, and with the increased public outreach and education regarding the handling of pesticides in general, a decreasing trend for these compounds should continue. The Sweetwater watershed drainage area consists of 50% vacant or undeveloped land, 30% residential and only 10% commercial. The contrast in land use compared to Chollas Creek may likely be the reason for better observed (based on data assessed) water quality in Sweetwater River. Only fecal coliform was identified as a high frequency of occurrence COC within Sweetwater River. TDS was identified as a medium frequency of occurrence COC, followed by turbidity, total coliform, enterococcus, and Diazinon, which were identified as low frequency of occurrence COC. The bioassessment monitoring identified Sweetwater River as having a Very Poor IBI score and was the lowest rated site in the county in the October Survey. In the ABLM program, the results of the chemistry assessment indicated that six of the nine metals assessed were found in Sweetwater River sediments. None of the six metals detected above the reporting limit exceeded its respective ERL or ERM value. The mean ERM quotient was 0.140 which exceeded the threshold value of 0.10. Sweetwater River Estuary ranked eight for chemistry, nine for toxicity, and three for benthic community structure relative to the other embayments assessed. Compared to the other embayments in the 2004 ABLM program, Sweetwater River Estuary had an Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-9 overall rank of eight. The relative quality in the Sweetwater River Estuary increased in 2004 compared with the 2003 ranking. For the San Diego Bay WMA, sediment was given a high priority (A) rating based on the BLTEA rating method followed by pesticides, bacteria, and benthic alterations which were given a B rating. The BLTEA findings are similar to the WMA assessments for both Chollas Creek and Sweetwater River. Turbidity, bacteria and Diazinon had a high frequency of occurrence in Chollas Creek, while bacteria had a high frequency of occurrence in Sweetwater River. There was evidence of benthic alteration in both sub-watersheds. 14.1.4.9 Tijuana River Watershed Management Area The Tijuana River watershed management area is the largest of the San Diego watersheds covering over 1.1 million acres. Mexico governs the majority of the Tijuana River watershed (73%) with the remaining areas belonging to the United States. Undeveloped areas account for 58% of U.S. lands, with another 25% devoted to parks. The River flows through Tijuana, Mexico and runoff contributions come from both Mexico and the United States. For the Tijuana River WMA, TSS, turbidity, all three bacterial indicators, and Diazinon were identified as high frequency of occurrence COC, followed by BOD, COD, ammonia, and total phosphorus which were identified as medium frequency of occurrence COC, and MBAS, dissolved phosphorus, Chlorpyrifos, Malathion, and total copper were identified as low frequency of occurrence COC. The elevated densities of all three bacterial indicators and elevated levels of BOD, COD, and nutrients (un-ionized ammonia as N and total phosphorus) are indicative of wastewater discharges. Pesticides are also a persistent problem in the watershed. Stream bioassessment monitoring rated the Tijuana River site as Poor, but the investigators in this study feel that this rating is much higher than the actual benthic community quality suggests. The two other bioassessment sites are upstream of any influence from the City of Tijuana and surrounding communities and are not representative of the lower reaches of the Tijuana River directly affected by runoff from these communities. Data collected during the Ambient Bay and Lagoon Monitoring program suggest the elevated concentrations of numerous constituents observed in the Tijuana River are not impacting estuarine sediments. The Tijuana Estuary sediments did not contain any PAHs, PCBs, or pesticides and results of toxicity tests were similar to those of a control. Overall, the Tijuana River Estuary received a rating of five compared to other embayments within San Diego County. The Tijuana River Estuary experienced a decrease in relative quality compared with the 2003 ABLM ranking. The BLTEA rating priorities agreed with the WMA assessment findings for the Tijuana Valley sub- watershed but since this sub-watershed is only 7% of the entire Tijuana River WMA, it suggests that the high priorities and COCs may be more localized to the area near the MLS. The Tijuana River WMA did not have any high priority (A) ratings for the overall WMA. The highest rated constituents were sediments, nutrients, gross pollutants, bacteria, and benthic alteration which were all given a B rating. 14.2 Program Review During the 2001-01 permit issuance, the Copermittees were required to review historical data and develop future recommendations. This was developed in the “San Diego Region Previous Storm Water Monitoring and Future Recommendations Report” (MEC 2001). This report put forth monitoring objectives for the 2001-01 permit term. The overall goal of monitoring expressed in the report was to “understand conditions of receiving waters within each watershed, identify water quality problems within Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-10 each watershed, and take actions to correct those problems so that beneficial uses are not degraded or impaired.” The design of the program included core monitoring, regional monitoring, and special studies. The intent of the monitoring design was to identify watersheds with water quality problems using the information collected during wet weather events at the base of the watershed, benthic community information, and information collected in the lagoons and embayments. This “prioritization” of watersheds was intended to provide a mechanism to focus special studies and upstream investigations into identification of the contributing sources to the water quality problems, as well as to provide additional characterization of those watersheds. The program design that was implemented in the 2001-2002 permit year was intended to provide: • Information relating to chemical, physical, and biological impacts to receiving waters resulting from urban runoff, • Indication of the overall health and long-term trends in water quality in the receiving waters. To date these two over-arching goals have been met by the monitoring design, however, additional questions resulting from the collected data have yet to be answered. Such questions include “What are the dry weather (ambient) concentrations of the urban runoff constituents?” and “How do the constituents of concern vary throughout the watershed?” In 2004, the Storm Water Monitoring Coalition (SMC) developed a Model Storm Water Monitoring Guidance Document. San Diego Region Copermittees had representatives who participated in the development of the guidance document. The SMC developed the guidance by framing five management questions which urban runoff monitoring should consider. The SMC acknowledged that these questions may not all be of equal import to jurisdictions, but rather can assist jurisdictions and jurisdictional groups in refining their monitoring programs. The five questions are: 1. What are the water quality conditions in the watershed? 2. Are water quality conditions in the watershed getting better or worse? 3. Are beneficial uses being impacted? 4. What is the relative contribution of urban runoff to the conditions in the watershed? 5. What are the sources to urban runoff that contribute to water quality conditions? The current Copermittee monitoring program can partially address these questions, however the program was initially designed to be adaptive through time and focus efforts toward identifying water quality problems in watersheds. Once watersheds with problems were identified, the adaptive part of the program is intended to move monitoring and assessment upstream in those priority watersheds to fully answer the management questions (MEC 2001). The current Copermittee monitoring program’s ability to fully answer the five management questions is limited by the present prescriptive requirements of the NPDES permit 2001-01. Currently the watershed data assessment utilizes the wet weather monitoring data at the mass loading stations, the benthic community assessments within the watersheds, dry weather information, limited third party data, and the Clean Water Act 303(d) listing to provide a management tool to stakeholders. The following describes the current monitoring program’s ability to address each question: Question 1: What are the water quality conditions in the watershed? This question is partially addressed through the current NPDES program, but a comprehensive watershed assessment is not Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-11 provided by the current program. The current monitoring program evaluates wet weather discharges at the base of the watershed for toxicity effect to freshwater organisms and chemical, bacterial, and general physical parameters. The current program provides bacterial monitoring at coastal outfalls, benthic community assessment at several locations within the watershed, and chemistry at limited locations within the watershed’s MS4 system. While these data are evaluated to provide an indication of potential water quality problems within the watershed, these disparate monitoring groups were not strategically designed to answer question 1 but are designed to meet permit requirements. Question 2: Are water quality conditions in the watershed getting better or worse? This question is partially addressed in the following ways: • Long-term trend assessment at the mass loading stations can provide an indication of improvements in the watershed. • Long-term trend assessment of the quality of the benthic community within the watershed. Question 3: Are beneficial uses being impacted? This question is only addressed through comparison to water quality objectives. For example, bacterial counts exceeding water quality objectives indicate an impact to recreational beneficial use. Question 4: What is the relative contribution of urban runoff to the conditions in the watershed? To answer the question of “relative” contribution requires knowledge of baseline conditions or a reference (non-urbanized) area for comparison. This question is not directly addressed in the current program; however, the current program does provide comparison between watersheds. This comparison of watersheds together with an assessment of different land use characteristics and an evaluation of concentrations of constituents of concern, occurrence and magnitude of toxic effects, and benthic community health yields an understanding of the impacts related to urbanization and various land uses. Question 5: What are the sources to urban runoff that contribute to water quality conditions? There are a variety of approaches to answer this question. The current program provides a mechanism to understand potential sources in urbanized watersheds. For example, Diazinon in urban watersheds comes from residential, commercial, or agricultural pest control. Where further source characterization and identification is required, a more focused study would be needed to answer the question. As outlined above, the current Copermittee monitoring program can partially address these questions, however the program was initially designed to be adaptive through time and focus efforts toward identifying water quality problems in watersheds. Once watersheds with problems were identified, the adaptive part of the program is intended to move monitoring and assessment upstream in those priority watersheds to provide additional information for management actions (MEC 2001). This adaptive philosophy is the same philosophy presented in the Model Monitoring Document. The SMC did not intend that permit monitoring would comprehensively address all five questions, nor was the intent that the stepwise approach as presented in the Model Monitoring Document would be followed in a linear, stepwise fashion, but rather that monitoring would be conducted based upon a prioritization of needs (SMC 2004). The current data from the monitoring program provides a strong foundation to form the basis of existing knowledge about water quality that was not available for all watershed management areas prior to 2001- 2002. Using this information, the Copermittees can refine their monitoring program to better address specific management questions and yield more baseline information against which improvements in water Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-12 quality can be measured. As the Copermittees enter into a new permit cycle in 2006-2007, it presents an opportune time to reassess the existing monitoring program together with the management questions to define the future monitoring program approach in the next permit cycle. Based on the review of the information obtained from the existing monitoring program and historical monitoring data, recommendations are presented in the next subsections for the next iteration of monitoring program to move the San Diego Region forward to continuing to understand urban runoff and its impacts. 14.3 Recommendations 14.3.1 2005-2006 Recommendations The recommended actions from the triad assessments are summarized in Table 14-2 and include continuing water quality monitoring in all watersheds to gather long-term trend information, investigating upstream sources of contaminants, and conducting TIEs in Chollas Creek and Sweetwater River. Since the EPA has banned the retail sale of Diazinon and Chlorpyrifos, and with the increased public outreach and education regarding the handling of pesticides in general, a decreasing trend for the organophosphate pesticide compounds is evident and should continue. Continued monitoring of the organophosphate compounds should show an overall decrease in the number of WQO exceedances and concentrations over time with the expectation that residual public supply and use will eventually be exhausted. However, the pesticide manufacturer’s shift to synthetic pyrethroids does warrant concern and monitoring should be considered for these analytes. Additional recommendations for 2005-2006 are to conduct a qualitative assessment of streambank erosion around mass loading and stream bioassessment stations, as well as to monitor for organochlorine and organophosphate pesticides, PAHs, PCBs, and synthetic pyrethroids at the Ambient Bay and Lagoon sampling locations. Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-13 Table 14-2. Recommended actions from the triad assessment. Watershed Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions Santa Margarita Persistent exceedances of water quality objectives No persistent evidence of toxicity No Indications of alteration Limited dataset makes conclusions difficult. Test organisms not sensitive to problem pollutants. Contaminants are not bioavailable. 1) Continue monitoring to gather long-term trend information. 2) Continue monitoring for toxic and benthic impacts. Consider whether different or additional test organisms should be evaluated. 3) Initiate upstream source identification as a low priority. 4) TIE would not provide useful information with no evidence of toxicity. San Luis Rey No persistent exceedances of water quality objectives No persistent evidence of toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) No action necessary based on toxic chemicals. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. Agua Hedionda Persistent exceedances of water quality objectives No persistent evidence of toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source identification as a high priority. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. 5) TIE would not provide useful information with no evidence of toxicity. Escondido Creek Persistent exceedances of water quality objectives No persistent evidence of toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source identification as a high priority. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. 5) TIE would not provide useful information with no evidence of toxicity. San Dieguito River No persistent exceedances of water quality objectives No evidence of persistent toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) No action necessary based on toxic chemicals. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. Los Peñasquitos No persistent exceedances of water quality objectives No evidence of persistent toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) No action necessary based on toxic chemicals 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-14 Table 14-2. Recommended actions from the triad assessment. Watershed Chemistry Toxicity Benthic Alteration Possible Conclusion(s) Possible Actions or Decisions Mission Bay Persistent exceedances of water quality objectives No evidence of persistent toxicity Indications of alteration Benthic impact due to habitat disturbance, not toxicity. Test organisms not sensitive to problem pollutants. 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source identification as a high priority. 3) Consider whether different test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. 5) TIE would not provide useful information with no evidence of toxicity. San Diego River Persistent exceedances of water quality objectives No evidence of persistent toxicity Indications of alteration Test organisms not sensitive to problem pollutants. Benthic impact due to habitat disturbance, not toxicity. 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source identification as a high priority. 3) Consider whether different or additional test organisms should be evaluated. 4) Consider potential role of physical habitat disturbance. 5) TIE would not provide useful information with no evidence of toxicity. Chollas Creek Persistent exceedances of water quality objectives Evidence of persistent toxicity Indications of alteration Evidence of current pollution-induced degradation 1) Continue monitoring to gather long-term trend information. 2) Continue to perform TIE to identify contaminant(s) of concern based on TIE metric. Sweetwater River No persistent exceedances of water quality objectives Evidence of persistent toxicity Indications of alteration Toxicity may be caused by contaminants not currently monitored for or synergistic effects of multiple constituents at low levels. The benthic alterations may be due to physical habitat disturbances. 1) Continue monitoring to gather long-term trend information. 2) Continue to perform TIE to identify contaminant(s) of concern based on TIE metric. Tijuana River Persistent exceedances of water quality objectives Evidence of persistent toxicity Indications of benthic alteration Connections of water quality degradation and toxicity to benthic condition difficult due to spatial disparity. 1) Continue monitoring to gather long-term trend information. 2) Evaluate upstream source identification as a high priority. 14.3.2 2007-2010 Recommendations As summarized in the above conclusions, the current monitoring program has addressed the overall objective of the 2001-01 permit term of identifying water quality issues and priorities on a watershed basis. Based on the results of the monitoring program, water quality priority ratings on a watershed basis were presented in the Regional Assessment section using the methodology developed in the Baseline Long-Term Effectiveness Assessment (BLTEA) report (WESTON, MOE, & LWA 2005). However, the current Copermittee monitoring program’s ability to fully answer the five management questions from the Model Monitoring Document (SMC 2004) is limited by the present prescriptive requirements of the NPDES permit 2001-01. In order to move the program forward using the current knowledge base and Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-15 the tools from the Model Monitoring Document and BLTEA, an adaptive monitoring approach is recommended for the next permit cycle. The fundamental recommended modification is an integrated and adaptive management approach to better address the key questions listed above and to utilize available resources effectively in the assessment of water quality in the region’s receiving waters. The major components of this recommended integrated and adaptive monitoring approach are summarized below, followed by more specific recommendations. The recommended monitoring approach would rely on both weight of evidence to assess conditions, as well as, comparison to water quality objectives. This integrated and adaptive approach will provide a better ability to answer the SMC’s five management questions. The recommended integrated monitoring program would provide a better linkage between the regional monitoring and the municipal dry weather IC/ID monitoring in the MS4. The recommended adaptive approach would provide a mechanism for moving upstream and segmenting the watershed. The recommended program would allow for development of complete load estimates and provide additional data for understanding watersheds and meeting TMDL needs. The recommended program would be a holistic approach that integrates monitoring both spatially and temporally. This program would include seasonal sampling to provide an indication of loads from urban runoff both during wet weather (storm events) and dry weather (non-storm events). It would link together information from the mass loading stations with information from assessment stations upstream in the watersheds together with co-located bioassessment stations. It would continue to provide the triad perspective of evaluating constituents of concern, biological response in the environment, and toxicity to test organisms. Figure 14-1 presents the recommended monitoring program in an idealized watershed where A is representative of a watershed that discharges to an enclosed bay or lagoon and B is representative of a watershed that discharges directly to the ocean. This graphic is similar to a graphic presented in the SMC Model Monitoring Program and incorporates many of the same monitoring elements. Figure 14-1. Recommended Monitoring Stations in an Idealized Watershed. Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-16 More specific recommended modifications to the current program are summarized below to provide an integrated and adaptive approach to better meet the long-term objectives in a resource efficient manner: Mass Loading Stations (MLS) Mass loading stations (MLS) would remain at the same sites where they have been established for the 2001-2005 program. These stations would be sampled on a rotating schedule of every other year. They would be flow-weighted composite samples collected during two wet weather storm events and two dry weather flow events. They would be tested for the existing constituent list, including toxicity testing. Bioassessment stations would be co-located as close as possible to MLS and be sampled during the same period (spring/fall). Watershed Assessment Stations (WAS) Watershed Assessment Stations (WAS) would be located in the upstream areas of each watershed management area. The scientific design rationale for selecting site locations shall be: 1. At major land use changes on water course. 2. Immediately downstream of tributaries. These assessment stations will be sampled in the same manner as the MLS. They will be on the same rotational schedule of every other year coincident with the MLS. They would include two wet weather events and two dry weather events with the existing constituent list and toxicity testing. Bioassessment stations would be co-located as close as possible to WAS and sampled during the same dry period (spring/fall). Bioassessment Monitoring (BA) Bioassessment monitoring locations would be co-located as much as possible with both mass loading stations and watershed assessment stations. Bioassessment monitoring would continue to occur twice per year, once in late spring (to represent the influence of wet weather on the communities) and one in late summer/October (to represent the influence of dry weather flows on the communities). These would also be on the same rotational cycle coincident with the MLS and WAS. Whenever possible the two dry weather sampling events at both MLS and WAS would be collected during the same period (late spring and late summer) as the bioassessment monitoring. This will provide temporal informational linkage for the data assessment process. Using this program design strategy, every other year a watershed will have all three monitoring elements: MLS, WAS, and bioassessment. The resultant information from this integrated monitoring approach will provide a solid basis for management activities. Toxicity Evaluation Identification Testing (TIE) TIEs would continue to be a useful tool to identify the constituents of concern responsible for causing persistently observed toxicity. In the event that emerging chemicals that are not tested for are discharged through the MS4s and result in toxicity, this analytical tool would allow for the evaluation and detection of these compounds. A possible example of this could be the shift from the use of organophosphate pesticides to the use synthetic pyrethroids. The TIE triad assessment approach would continue to be employed for this monitoring program. No additional TIE assessment would be performed for Tijuana because of the known continued source of toxicity from untreated sewage discharges. Until this source is addressed, additional TIE assessment will not provide additional data from which management actions can be further defined. Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-17 Ambient Bay and Lagoon Monitoring Program (ABLM) The Ambient Bay and Lagoon Monitoring started collecting samples in 2003. At the present time there have been two monitoring events. It is recommended that this program continue as designed to collect at least three years worth of data. After the third monitoring year’s information has been collected the program shall be assessed to adapt the monitoring design. Following three years of monitoring, information/data shall be assessed to look for a relationship/linkage between the mass loading stations and ABLM stations. If a relationship is observed, then the Ambient Bay and Lagoon monitoring program shall be linked into the program design as a monitoring element to be conducted with the MLS, WAS, and BA monitoring and the information/data assessed as an additional weight of evidence element. However, if a relationship between the mass loading stations and the ABLM program is not observed, then the ABLM program will be adapted to conduct special investigations on those areas which have been identified as having the most water quality issues based on toxicity, chemistry, and/or benthos. 14.3.2.1 Recommended 2008/2009 Program For monitoring year 2008-2009, it is recommended that a single sampling event be collected during wet weather at each MLS to continue the trend data record. The remaining effort for that year is recommended to be used for participation in the Southern California Bight Monitoring Program. Participating in the Bight monitoring program provides many benefits to the San Diego Region and it matches the SMC Model Monitoring Program recommendation that regional monitoring participate in larger scale regional monitoring programs. The benefits to the region include the ability to obtain a regional comparison (a larger spatial comparison) of San Diego County to the rest of Southern California to provide a bigger picture assessment of our region in context with other similar areas. It provides a larger-scale approach to monitoring and typically includes more spatial distribution of monitoring as well as a more lengthy constituent list and additional measures (such as fish communities). Further, the Bight monitoring typically provides additional information about the current status of receiving waters. 14.3.2.2 Sampling Schedule The recommended monitoring program greatly increases the number of monitoring stations throughout the county. To accomplish the program, stations would be rotated to maximize monitoring resources. This approach is supported by the SMC Model Monitoring program. “Rotating designs, in which a different subset of stations is sampled during each sampling event, with the goal of sampling the entire set over a certain period of time. …Maximizes the impact of limited monitoring resources. Locations of stations can be random, systematic, or early warning depending upon the type of questions asked.” A more detailed scheduled for station rotation shall be developed in coordination with the Copermittees. 14.3.2.3 Consistency with SMC 2004 Document The Model Monitoring document provides a process for “improving the program’s ability to build appropriate linkages among the five core management questions.” The document defines a process to adapt a monitoring program to improve ability to answer those questions based upon specific needs and the prioritization of those needs. The steps described in the document to adapt a monitoring program are: 1. Evaluate a program’s ability to answer each of the five management questions. 2. Identify critical gaps in knowledge relevant to each program’s circumstances. Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-18 3. Use the monitoring designs in the model monitoring program as a framework for developing monitoring components suited to each program’s circumstances. Through this process the ultimate goal of regionally consistent programs that directly address the key management questions in a scientifically rigorous and cost effective manner can be achieved (SMC 2004). How effectively does the proposed monitoring design answer the SMC Model Monitoring Program’s five key management questions? Question 1: What are the water quality conditions in the watershed? This question will be more fully answered with the recommended program design. The recommended design will provide increased spatial coverage to understand water quality conditions in the watersheds by segmenting each watershed with WAS and BA stations. It will provide increased temporal coverage by collecting samples during both wet weather events and dry weather events. This will provide a complete load estimate and allow for understanding of water quality conditions during dry weather periods both in the spring when rain has increased the baseflow of the creeks, streams and rivers, and in fall at the end of the summer period. Further, the recommended monitoring design will provide a complete ability to conduct a weight-of-evidence assessment of water quality, in addition to a compliance assessment to water quality objectives by holistically linking monitoring sites to allow the most effective spatial and temporal assessment. Question 2: Are water quality conditions in the watershed getting better or worse? The ability to detect trends is not significantly reduced. Statistical assessments using power analyses and other statistical tools for 95 different scenarios utilizing existing Copermittee MLS data found a time extension to detect trends in some instances, while not in other instances. For all statistically significant decreasing trends in water quality constituents currently measured in the program, modifying the program to the recommended approach will result in an increased time period of 6.4% until the mean measured value crosses the water quality objective. For increasing trends in water quality constituents currently measured in the program, an assumption of increase and then slope change to decreasing concentrations toward the water quality objective were modeled. Using this model, modifying the program resulted in NO change in time period to be able to observe the mean measured value drop below the water quality objective. For those constituents currently measured with no apparent trend in water quality, there will also be NO change in time period to detect a trend. It is important to note that the simulations used empirical data from the existing program. If the current trend slope is changed due to increases in constituents in the watershed or decreased concentrations of constituents in the watershed, the recommended program will have the ability to detect these changes. The ability to determine if water quality conditions are getting better or worse is currently only answered with storm water discharge, however, the new program design will provide the ability to answer this question during dry weather flow conditions as well. Question 3: Are beneficial uses being impacted? This question can be answered more effectively with the proposed monitoring design. The holistic approach to bioassessment station placement co-located at or near MLS and WAS will provide the ability to address this question with both a weight-of-evidence and a compliance approach. Question 4: What is the relative contribution of urban runoff to the conditions in the watershed? To answer the question of “relative” contribution requires knowledge of baseline Conclusions and Recommendations SECTION 14 2004-2005 Urban Runoff Monitoring Report 14-19 conditions or a reference (non-urbanized) area for comparison. This question is not directly addressed in the current program; however, the current program does provide comparison between watersheds. This comparison of watersheds together with an assessment of different land use characteristics and an evaluation of concentrations of constituents of concern, occurrence and magnitude of toxic effects, and benthic community health yields an understanding of the impacts related to urbanization and various land uses. The information resultant from the recommended program will be beneficial baseline information from which to gain a better understanding of relative contribution of urban runoff, however, it will not directly answer this question. Question 5: What are the sources to urban runoff that contribute to water quality conditions? The recommended program will result in more information relative to sources and provide a better linkage to understanding existing sources both in wet and dry weather. Segmenting the watershed using WAS will result in a better understanding of locations of sources and linkage to the municipal dry weather IC/ID program will allow further information relative to sources of water quality problems. In conclusion, the recommended program will advance the understanding of conditions in San Diego County watersheds. It is a holistic program that uses both a weight-of-evidence plus a compliance approach. The program is designed to better address the five SMC key management questions and provide an integration with the jurisdictional dry weather IC/ID program. Through segmenting the watersheds and adding new stations it will provide additional watershed information relative to magnitude and extent, as well as provide increased spatial coverage to focus management efforts. Linkage with the jurisdictional dry weather IC/ID program and watershed segmentation will provide a better mechanism to identify potential sources. Further, the recommended program provides an integration of program elements while resulting in little loss of the ability to detect trends. Moreover, the recommended program provides a more comprehensive view of the watersheds with the addition of dry weather monitoring to complete the loading picture and provide increased information value for future TMDLs. References SECTION 15 2004-2005 Urban Runoff Monitoring Report 15-1 15.0 REFERENCES Bailey, H.C., C. DiGiorgio, K. Kroll, J.L. Miller, D.E. Hinton, G. Starrett. 1996. “Development of Procedures For Identifying Pesticide Toxicity In Ambient Waters: Carbofuran, Diazinon, Chlorpyrifos.” Environmental Toxicology and Chemistry 17(6):837-845. Barbour, M.T., J. Gerritsen, B.D. Snyder, and J.B. Stribling. 1999. Revision to rapid bioassessment protocols for use in stream and rivers: periphyton, BMIs and fish. EPA 841-D-97-002. U.S. Environmental Protection Agency. Washington D.C. Behrens, D.B. 1991. Pacific Coast Nudibranchs. Sea Challengers, Monterey, CA. 107 pp. California Regional Water Quality Control Board, San Diego Region (RWQCB). 1990. Waste Discharge Requirements for Storm Water and Urban Runoff. Order No. 90-42. NPDES No. CA 0108758. California Regional Water Quality Control Board, San Diego Region (RWQCB). 1994. Water Quality Control Plan for the San Diego Basin. California Regional Water Quality Control Board, San Diego Region (RWQCB). 1995. Waste Discharge Requirements for Storm Water and Urban Runoff. Order No. 95-76. NPDES No. CA 0108758. California Regional Water Quality Control Board, San Diego Region (RWQCB). 2001. Order No. 2001- 01. California Regional Water Quality Control Board, San Diego Region (RWQCB). 2001. Biological Assessment Annual Report. California Department of Fish and Game, Office of Spill Prevention and Response, Water Pollution Control Laboratory. Rancho Cordova, California. California Regional Water Quality Control Board, San Diego Region (RWQCB). 2002. Combined 1998 and Draft Section 303(d) Update. California State Assembly Bill 411 – Title 17 of the California Code of Regulations, Section 7958. Carr, R.S., Chapman, D.C., Howard, C.L., and J.M. Biedenbach. 1996. Sediment quality triad assessment survey of the Galveston Bay, Texas system. Ecotoxicology 5, 341-364. Chapman, J.W. and J.A. Dorman. 1975. Diagnosis, systematics, and notes on Grandidierella japonica (Amphipoda: Gammaridae) and its introduction to the Pacific coast of the United States. Bull. S. Calif. Acad. Sci. 74:104-108. Chapman, P.M. 1996. Presentation and Interpretation of Sediment Quality Triad Data, Ecotoxicology 5: 327-39. City of Austin, Texas. Environmental and Conservation Services Department Environmental Resources Management Division. 1990. The First Flush of Runoff and Its Effects on Control Structure Design. Coastal Conservancy. 2001. Southern California Wetlands Recovery Project: Watershed Descriptions. Available Online: http://eureka.regis.berkeley.edu/wrpinfo/. References SECTION 15 2004-2005 Urban Runoff Monitoring Report 15-2 Deméré, Thomas A., Ph.D. 2005. Geology of San Diego County, California. San Diego Natural History Museum. Available Online: http://www.sdnhm.org/research/paleontology/sdgeol.html Earl, S.R. and D.W. Blinn. 2000. Implications of Forest Fires on Water Quality and Biota of Streams in the Gila National Forest, New Mexico. Presented at the North American Benthological Society meeting on Effects of Deforestation and Fire. May 31st, 2000. EMAP. 1997. See Anderson et al. 1997. Federal Highway Administration. 1990. “Pollution Loading and Impacts from Highway Storm Water Runoff, Volume3; Analytical Investigation and Research Report,” FHWA-D-88-008, McLean, Virginia, April 1990. Gibbs, R.J. 1973. Mechanisms of trace metal transport in rivers. Science 180:71-73. Harrington, J.M. 1999. California stream bioassessment procedures. California Department of Fish and Game, Water Pollution Control Laboratory. Rancho Cordova, CA. Hyland, J.L., Van Dolah, R.F., and T.R. Snoots. 1999. Predicting stress in benthic communities of southeastern U.S. estuaries in relation to chemical contamination of sediments. Environmental Toxicology and Chemistry 18(11), 2557-2564. Kennish, M.J. 1998. Pollution Impacts on Marine Benthic Communities. CRC Press, New York. 310 p. Kinnetic Laboratories, Incorporated, ToxScan, Incorporated. July, 1994. 1993-1994 City of San Diego and Co-Permittee NPDES Storm water Monitoring Program. In Association with Camp, Dresser, and McKee, Inc., Cooper Engineering Associates, and Quality Assurance Laboratory. Kinnetic Laboratories, Incorporated, ToxScan, Incorporated. July, 1995. City of San Diego and Co- Permittee NPDES Storm water Monitoring Program, 1994 - 1995. In Association with Camp, Dresser, and McKee, Inc., Cooper Engineering Associates, and Quality Assurance Laboratory. Ladaa, T., G. Bielmyer, and K.L. Murphy. 1998. Organophosphates. Clemson University, EE&S Department. Available on-line: http://www.ces.clemson.edu/ees/lee/organophosphates.html Long, E.R. and L.G. Morgan. 1990. The Potential for Biological Effects of Sediment-sorbed Contaminants Tested in the National Status and Trends Program. NOAA Tech. Mem. NOS OMA 52. Long, E.R. and D.D. MacDonald. 1992. National Status and Trends Program Approach. Sediment classification methods compendium. 823-R-92-006. U.S. Environmental Protection Agency, Washington, DC. Long, E.R., D.D. MacDonald, S.L. Smith, and F.D. Calder. 1995. Incidence of adverse biological effects within ranges of chemical concentrations in marine and estuarine sediments. Environmental Management 19:81-97. Long, E.R., Scott, G.I., Kucklick, J., Fulton, M., Thompson, B., Carr, R.S., Scott, K.J., Thursby, G.B., Chandler, G.T., Andreson, J.W., and G.M. Sloane. 1995. Final Report. Magnitude and extent of sediment toxicity in selected estuaries of South Carolina and Georgia. NOAA Technical Memorandum NOS ORCA: 178 p. References SECTION 15 2004-2005 Urban Runoff Monitoring Report 15-3 Long, E.R., Field, L.J., and MacDonald, D.D. 1998. Predicting toxicity in marine sediments with numerical sediment quality guidelines. Environmental Toxicology and Chemistry 17(4), 714-727. MEC Analytical Systems, Inc (MEC). 2001. San Diego Region Previous Storm Water Monitoring Review and Future Recommendations, Final Report. Submitted to the City of San Diego, August 2001. MEC Analytical Systems, Inc (MEC). 2002. 1999-2001 Chollas Creek Watershed Monitoring, Final Report. Submitted to the City of San Diego, May 2002. MEC Analytical Systems, Inc. 2003. San Diego County Municipal Copermittees 2001-2001 urban runoff monitoring. Prepared for the County of San Diego. January, 2003. MEC Analytical Systems, Inc. – Weston Solutions, Inc. 2005. San Diego County Municipal Copermittees 2003-2004 Urban Runoff Monitoring. Prepared for the County of San Diego. January, 2005. Meixner. 2004. Wildfire Impacts on Water Quality. Southwest Hydrology. 24-25. Moore, J.N., E.J. Brooks, and C. Johns. 1989. Grain size partitioning of metals in contaminated coarse- grained river flood plain sediment, Clark Fork River, Montana, USA. Environmental Geology and Water Science 14:107-115. National Weather Service (NWS). 2002. Online Record Event Report. http://www.wrh.noaa.gov/ sandiego/driest.html. National Weather Service (NWS). 2002. San Diego Lindbergh Field Monthly Precipitation Totals. Available online: http://www.wrcc.dri.edu/cgi-bin/cliMONtpre.pl?casand. National Weather Service (NWS). 2004. San Diego Lindbergh Field Monthly Precipitation Totals. Available online: http://www.nws.noaa.gov/ National Weather Service (NWS). 2005a. Coast to Cactus Weather Examiner, Volume 11, Number 1. National Weather Service (NWS). 2005b. Coast to Cactus Weather Examiner, Volume 11, Number 3. Ode P.R., A.C. Rehn, J.T. In Press. A Benthic Macroinvertebrate Index of Biotic Integrity for Southern Coastal California. Unpublished Manuscript. December 2003. Ode P.R., A.C. Rehn, and J.T. May. 2005. A quantitative tool for assessing the integrity of Southern Coastal California streams. Environmental management, 35 (1): 1-13. Plumb, R.H., Jr. 1981. Procedures for handling and chemical analysis of sediment and water samples. Technical Report EPA/CE-81-1. U.S. Environmental Protection Agency/U.S. Corps of Engineers Technical Committee on Criteria for Dredged and Fill Material. U.S. Army Waterways Experiment Station, Vicksburg, MS. 471 pp. San Diego Association of Governments (SANDAG). 1998. SANDAG INFO, Watersheds of the San Diego Region. March-April 1998. San Diego Association of Governments (SANDAG). 2000. San Diego Region, 1990 Generalized Land Use Map. References SECTION 15 2004-2005 Urban Runoff Monitoring Report 15-4 San Diego County Project Clean Water. 2001. Phase 1 Results Report. San Diego County Project Clean Water. 2002. Major Watersheds in the San Diego Region Map. Available Online: http://www.projectcleanwater.org/html/ws_map.html. San Diego County Water Authority (SDCWA). 2000. Urban Water Management Plan. Available Online: http://www.sdcwa.org/news/plan2000.html. San Diego Regional 303(d) Copermittee Workgroup (303(d) Workgroup). 2002. An Analysis of Proposed 303(d) Listings in San Diego County Watersheds. County of San Diego correspondence dated May 16, 2002. Prepared for California State Water Resources Control Board. Shannon, C.H. and W. Weaver. 1962. The Mathematical Theory of Communication. Univ. Illinois, Urbana IL. 177pp. Siepmann, S. and B. Finlayson. 2000. Water Quality Criteria for Diazinon and Chlorpyrifos. California Department of Fish and Game Administrative Report 00-3. 65pp. State Water Resources Control Board (SWRCB). 2003. 2002 CWA Section 303(d) List of Water Quality Limited Segments. Steuber and Nold. 1986. Climatic Data Summaries from Hourly Precipitation Data and State Climatic Divisions. Washington, D.C. Stormwater Monitoring Coalition’s Model Storm Water Monitoring Program. 2004. Model Monitoring Program for Municipal Separate Storm Sewer Systems in Southern California. Technical Report #419. August 2004. Sullivan, Johnathan J. and Ken S. Goh. 2000. Evaluation and Validation of a Commercial ELISA for Diazinon in Surface Waters. Journal of Agricultural and Food Chemistry, Volume 48, Number 9, Pages 4071-4078. TEK Environmental Testing Laboratory, MBC Applied Environmental Sciences, MGD Technologies, Inc, and Weatherwatch Services. August 10, 1998. Texas Nonpoint Sourcebook. 2002. Available Online: http://www.txnpsbook.org/ Tiefenthaler, Liesl, K. Schiff, and S. Bay. 2001. Characteristics of parking lot runoff produced by simulated rain. Southern California Coastal Water Research Project, Westminster, CA. U.S. Census Bureau. 2000. Available Online: http://quickfacts.census.gov/qfd/states/06/06073.html. U.S. Environmental Protection Agency (EPA). 1983. Results of the Nationwide Urban Runoff Program, Volume 1 – Final Report. U.S. Environmental Protection Agency (EPA). 1994. Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. 3rd ed. EPA-600/4-91-002. Cincinnati, OH. References SECTION 15 2004-2005 Urban Runoff Monitoring Report 15-5 U.S. Environmental Protection Agency and United States Army Corps of Engineers (USEPA/USACE). 1998. Evaluation of Dredged Material Proposed for Discharge in Waters of the U.S: - Testing Manual. EPA 823-B-98-004. EPA Office of Water. February. U.S. Environmental Protection Agency (EPA). 2000. Federal Register Document 40 CFR Part 131. May 18, 2000. U.S. Environmental Protection Agency (EPA). 2000. National Pollutant Discharge Elimination System (NPDES) Storm Water Multi-Sector General Permit for Industrial Activities. 65 Federal Register (FR) 64746. October 30, 2000. U.S. Federal Highway Administration (FHWA). 1990. Pollutant Loading and Impacts from Highway Storm Water Runoff, Volume; Analytical Investigation and Research Report. FHWA-RD-88-008. McLean, VA. URS Greiner Woodward-Clyde (URSGWC). 1999. City of San Diego and Co-Permittees NPDES Storm Water Monitoring Program. August 1999. URS Greiner Woodward-Clyde (URSGWC). 2000. 1999-2000 City of San Diego and Co-permittee NPDES Storm Water Monitoring Program Report. Prepared for the City of San Diego Engineering and Development Department. In association with APPL, Inc., California Watersports, D-TEK Environmental Testing Laboratory, MBC Applied Environmental Sciences, MGD Technologies, Inc, Motile Laboratory Services, and University of Washington. July 14, 2000. Usinger, R.L. 1956. Aquatic insects of California. University of California Press, Berkeley, California. Verschueren, K. 1983. Handbook of Environmental Data on Organic Chemicals. New York: Van Nostrand Reinhold Company, Inc. Walker, J. F., S. A. Pickard, and W. C. Sonzogni. 1989. Spreadsheet Watershed Modeling for Nonpoint Source Pollution Management in a Wisconson Basin. Water Resources Bulletin, American Water Resources Association. 25(1):139-147. Watershed Data Assessment Framework. 2004. Final Draft, Version 1. Prepared for San Diego Storm Water Copermittees. Prepared by MEC Analytical Systems, Inc.-Weston Solutions, Inc. June 2004. Weston Solutions, Inc., Mikhail Ogawa Engineering (MOE), and Larry Walker Associates (LWA). 2005. Baseline Long-Term Effectiveness Assessment. Prepared for the San Diego County Copermittees. August, 2005. Woodward-Clyde Consultants. 1996a. 1995-1996 City of San Diego and Co-Permittee NPDES Storm Water Monitoring Program. Prepared for the City of San Diego Engineering and Development Department. In association with ADS Environmental Services, Inc., Ceimic Corporation, and MBC Applied Environmental Sciences. August 1996. Woodward-Clyde Consultants. 1998. 1997-1998 City of San Diego and Co-permittee NPDES Storm Water Monitoring Program Report. Prepared for the City of San Diego Engineering and Development Department. In association with Ceimic Corporation, D- References SECTION 15 2004-2005 Urban Runoff Monitoring Report 15-6 Yoder, C.O. and E.T. Rankin. 1998. The role of biological indicators in a state water quality management process. Environmental Monitoring and Assessment 51: 61-68.