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Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 GEOHYDROLOGIC INVESTIGATION OF THE LOWER SAN LUIS REY RIVER VALLEY SAN DIEGO COUNTY, CALIFORNIA CONTENTS LO EXECUTIVE SUMMARY 1 2.0 INTRODUCTION 11 2.1 Background and Previous Investigations 12 2.2 Data Gaps Identified From Phase 1 14 2.3 Data Gaps Identified During Piiase 2B 15 2.4 Phase 2C Purpose and Scope 15 3.0 DESCRIPTION OF AREA 17 ^. 3.1 Project Location ...17 3.1.1 Mission Basin 17 3.1.2 Bonsall Basin '. 17 3.2 Topography and Physiography 18 3.3 Climalological Characteristics 18 4.0 REGIONAL GEOLOGIC SETTING : 20 4.1 Geologic Structure 21 4.2 Stratigraphy 22 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 CONTENTS (Continued) 5.0 REGIONAL GEOHYDROLOGIC SETTING 25 5.1 Surface Water 26 5.2 Groundwater 27 5.2.1 Aquifer Systems 27 5.2.2 Groundwater Flow 28 5.2.3 Historical Groundwater Levels 28 5.2.4 Aquifer Characteristics 29 5.2.4.1 Alluvial Aquifer 29 5.2.4.2 Bedrock Aquifer 30 5.2.5 Mission Basin Groundwater Budget 30 5.2.5.1 Estimates of Groundwater Recharge 30 5.2.5.2 Estimates of Groundwater Discharge 33 5.2.5.3 Net Change in Groundwater Budget 34 5.2.6 Groundwater Quality 34 5.2.7 Current Groundwater Use 36 6.0 PROJECT SITES 37 6.1 Mission Basin Sites 37 6.1.1 Site 1 37 6.1.2 Site 2A 38 6.1.3 Site 2B 39 6.1.4 Site 3B 40 6.1.5 Site 3C 40 6.1.6 Site 7A 41 6.1.7 Site 9A 42 6.1.8 Site lOA 42 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 CONTENTS (Continued) 6.1.9 Site 11 43 6.1.10 Site lie 44 6.1.11 Site 13 44 6.1.12 Site 13A ; 45 6.1.13 Site 32 : 45 6.1.14 Desalter Site 46 6.2 Bonsall Basin Site 47 7.0 FIELD INVESTIGATION PROGRAM METHODOLOGY 49 7.1 Surface Resistivity Survey 50 7.2 Exploratory Boreholes 50 7.2.1 Soil Sampling 51 7.2.2 Depth-Specific Groundwater Samphng 52 7.2.3 Geophysical Borehole Logging 52 7.3 Groundwater Monitoring Wells 53 7.3.1 Construction and Completion Details 54 7.3.2 Development 56 7.3.3 Groundwater Sample Collection 56 7.4 Site 1 Test Well (IC/TWl) 56 7.4.1 Construction and Completion Details 57 7.4.2 Pumping Test 57 7.5 Desalter Site - Well D/TW1/PW9 58 7.5.1 Conductor Casing Installation 58 7.5.2 Pilot Borehole Drilling 58 7.5.3 Geophysical Borehole Logging 59 7.5.4 Aquifer Zone Testing for Yield and Water Quality 60 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority iii Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 CONTENTS (Continued) 7.5.5 Filter Pack, Casing and Screen Design 62 7.5.6 Well Development 63 7.5.7 Plumbness and Alignment Survey 64 7.5.8 Pumping Tests 65 7.5.8.1 Step-Drawdown Test 66 -7.5.8.1.1 Step-Drawdown Data Evaluation Methodology 66 7.5.8.1.2 Summary of Data 68 7.5.8.2 Constant Rate Test 69 7.5.8.2.1 Pumping Test Procedure 69 7.5.8.2.2Constant Rate Data Evaluation Methodology 71 7.5.8.2.3 Summary of Data 76 7.5.9 Groundwater Sample Collection 76 7.5.10 Spinner (Flowmeter) Survey 77 7.5.11 Downhoie Video Survey 77 7.6 Oceanside Desalter Pumping Test 77 7.6.1 Pumping Test Procedure 78 7.6.2 Data Evaluation Methodology 80 7.6.3 Summary of Data 81 8.0 RESULTS OF FIELD INVESTIGATION PROGRAM - MISSION BASIN 83 8.1 Stratigraphy 83 8.1.1 Alluvium 83 8.1.2 Bedrock 84 8.1.2.1 Granitic Bedrock : 84 8.1.2.2 Sedimentary Bedrock 85 8.2 Aquifer Systems 86 GEOSCIENCE Suppoit Services, Inc. Tetra Tech/San Diego County Water Authority iv Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 CONTENTS (Continued) 8.2.1 Shallow Alluvial Aquifer 87 8.2.1.1 Groundwater Occurrence and Flow ." 88 8.2.1.2 Source of Recharge 88 8.2.1.3 Aquifer Characteristics 89 8.2.2 Deep Alluvial Aquifer 89 8.2.2.1 Groundwater Occurrence and Flow 90 8.2.2.2 Source of Recharge 90 8.2.2.3 Aquifer Characteristics 91 8.2.3 Bedrock Aquifer 92 8.2.3.1 Groundwater Occurrence and Flow 92 8.2.3.2 Source of Recharge 93 8.2.3.3 Aquifer Characteristics 93 8.2.4 Relationship Between Bedrock and Alluvial Aquifers 94 8.3 Groundwater Quality 95 8.3.1 Shallow Alluvial Aquifer 96 8.3.2 Deep Alluvial Aquifer 96 8.3.3 Sedimentary Bedrock Aquifer 97 8.4 Volume of Groundwater in Storage 97 9.0 RESULTS OF FIELD INVESTIGATION PROGRAM - BONSALL BASIN 100 9.1 Lithology : 100 9.1.1 Alluvium 100 9.1.2 Bedrock 100 9.2 Alluvial Aquifer System 100 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 CONTENTS (Continued) 10.0 CONCLUSIONS AND RECOMMENDATIONS 102 10.1 Mission Basin 102 10.1.1 General Conclusions 102 10.1.2 Sitel 103 10.1.2.1 Site 1 Conclusions 103 10.1.2.2 Site 1 Recommendations 105 10.1.3 Site2A 106 10.1.3.1 Site 2A Conclusions 106 10.1.3.2 Site 2A Recommendations : 108 10.1.4 Site2B 109 I0.J.5 Site3B 110 10.1.5.1 Site 3B Conclusions 110 10.1.5.2 Site3B Recommendations Ill 10.1.6 Site3C Ill 10.1.6.1 Site 3C Conclusions Ill 10.1.6.2 Site 3C Recommendations 113 10.1.7 Site7A 114 10.1.7.1 Site 7A Conclusions ; 114 10.1.7.2 Site 7A Recommendations 115 10.1.8 Site9A 116 10.1.8.1 Site 9A Conclusions 116 10.1.8.2 Site9A Recommendations 117 10.1.9 Site lOA = 119 10.1.9.1 Site 1 OA Conclusions 119 10.1.9.2 Site 1 OA Recommendations 120 10.1.10 Site 11 121 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority vi Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 CONTENTS (Continued) 10.1.10.1 Site 11 Conclusions ; 121 10.1.10.2 Site 11 Recommendations 123 10.1.11 Site UC 124 10.1.11.1 Site nc Conclusions 124 10.1.12 Site 13 . 125 10.1.12.1 Site 13 Conclusions 125 10.1.12.2 Site 13 Recommendations 126 10.1.13 Site 13A 127 10.1.13.1 Site 13A Conclusions 127 10.1.13.2 Site 13A Recommendations 128 10.1.14 Site 32 129 10.1.14.1 Site 32 Conclusions 129 10.1.14.2 Site 32 Recommendations 130 10.1.15 Desalter Site 131 10.1.15.1 Desalter Site Conclusions 131 10.1.15.2 Desalter Site Recommendations 132 10.2 Potential Geohydrologic Constraints to Conjuctive Use in the Mission Basin 133 10.2.1 Potential Environmental Impacts to the Riparian Habitat Along the San Luis Rey River 134 10.2.2 Potential for Land Subsidence....." 134 10.2.3 Potential for Liquefaction 136 10.3 Bonsall Basin 136 10.3.1 Site 26/27 Conclusions 136 10.3.2 Site 26/27 Recommendations 137 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority vn Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 CONTENTS (Continued) 11.0 REFERENCES 138 FIGURES, TABLES, PLATE, AND APPENDICES GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority viii Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 FIGURES No. Description 1 Regional View - San Luis Rey River Watershed 2 Lower San Luis Rey River Valley Investigation Areas 3 Mission Basin Investigation Sites 4 Bonsall Basin Investigation Site 5 Annual Precipitation Isohyetal Map with Annual Precipitation and Cumulative Departure from Mean Precipitation (Oceanside Marina and Vista 2NNE) 6 Mission Basin Geologic Map and Location of Geologic Cross Sections 7 Estimated Bedrock Elevation in the Mission Basin Area 8 Mission Basin Groundwater Elevations (2003) with Hydrographs 9 Location of Underground Storage Tanks (USTs) in Mission Basin 10 Photographs of Exploratory Borehole Drilling Operation 11 Photograph of Typical Soil Core Sample 12 Photograph of Installation of PVC Casing for Monitoring Well 13 Photograph of Nested Monitoring Well Completion GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority ix Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 FIGURES (Continued) No. Description 14 Photograph of Completed Monitoring Well 15 Test Well IC/TWl - Constant Rate Pumping Test 16 Photograph of Desalter Test Well D/TW1/PW9 Conductor Casing Installation 17 Desalter Test Well D/TW1/PW9 - Mechanical Grading Analysis Composite Plot 18 • Photograph of Desalter Test Well D/TW1/PW9 Casing Installation 19 Photograph of Drill and Reaming Bits used for Desalter Test Well Drilling 20 Desalter Test Well D/TW 1 /PW9 - Deviation Survey Plot 21 Desalter Test Well D/TW1/PW9 - Step Drawdown Test 22 Desalter Test Well D/TW1/PW9 - Specific Drawdown Plot 23 Desalter Test Well D/TW1/PW9 - Specific Capacity and Well Efficiency ^Diagram 24 . Desalter Test Well D/TW1/PW9 (Pumping Well) - 24 Hour Constant Rate Pumping Test 25 D/B2/MW1-S (Observation Well) - 24 Hour Constant Rate Pumping Test - Jacob's Straight Line Applied to Recovery GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 FIGURES (Continued) No. Description 26 OW-2 (140 West) (Observation Well) - 24 Hour Constant Rate Pumping Test - Jacob's Straight Line Applied to Recovery 27 Desalter Test Well D/TW1/PW9 - Distance Drawdown Plot 28 Desalter Test Well D/TW1/PW9 - Flowmeter Survey 29 PW-3 (Pumping Well) - 40 Hour Constant Rate Pumping Test 30 PW-2 (Observation Well) - 40 Hour Constant Rate Pumping Test 31 OW-2 (140 West) (Observation Well) - 40 Hour Constant Rate Pumping Test 32 D/B2/MW1-S (Observation Well) - 40 Hour Constant Rate Pumping Test 33 PW-2 (Observation Well) - 40 Hour Constant Rate Pumping Test Calculated Recovery 34 OW-2 (140 West) (Observation Well) - 40 Hour Constant Rate Pumping Test Calculated Recovery 35 D/B2/MW1-S (Observation Well) - 40 Hour Constant Rate Pumping Test Calculated Recovery 36 PW-3 (Pumping Well) - Distance Drawdown Plot GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority xi Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 FIGURES (Continued) No. Description 37 Extent of Aquitard in Mission Basin 38 Hydrographs of OW-1 Shallow and OW-1 (40 East) 39 Hydrographs of OW-6, OW-7, OW-8, and OW-9 40 Hydrographs of OW-1 (40 East), OW-2 (140 West) and OW-1 Shallow 41 Desalter Test Well D/TW1/PW9 Zone Testing - Groundwater Elevations in Alluvial and Bedrock Aquifers 42 OW-11 (Observation Well) - 40 Hour Constant Rate Pumping Test 43 D/B2/MW1-S and D/B2/MW1-D (Observation Wells) - 40 Hour Constant Rate Pumping Test 44 Trilinear Diagram - Mission Basin Alluvial Aquifer Groundwater 45 Trilinear Diagram - Mission Basin Bedrock Aquifer Groundwater 46 Estimated Groundwater in Storage in Mission Basin 47 Estimated Unsaturated Alluvial Thickness in Mission Basin 48 Trilinear Diagram - Bonsall Basin Alluvial Aquifer Groundwater GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority xii Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 TABLES No. Description J Summary of Monthly Evaporation Rates (in Inches) 2 Summary of Field Investigation Exploratory Boreholes 3 Summary of Field Investigation Monitoring and Test Wells 4 Summary of Soil Physical Properties Data 5 Water Quality Analysis Summary 6 Summary of Geophysical Borehole Log Testing 7 Summary of Aquifer Zone Test Field Results - Desalter Test Well D/TW 1/PW9 8 Summary of Well Completion Details - Desalter Test Well D/TW1/PW9 9 Deviation Survey Data - Desalter Test Well D/TW1/PW9 10 Summary of Aquifer Test Results - Desalter Test Well D/TW1/PW9 11 Summary of Aquifer Test Results - City of Oceanside Production Well PW-3 12 Groundwater Analytical Data - Inorganics 13 Groundwater Analytical Data - Metals 14 Groundwater Analytical Data - Miscellaneous Compounds. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority xiii Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 PLATE No. Description 1 Geohydrologic Cross Sections A-A' and B-B' GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority xiv Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 APPENDICES No. Description A Site-Specific Figures B Lithologic Logs C Soil Physical Properties D Laboratory Groundwater Analytical Reports Geophysical Borehole Logs Monitoring Well Completion Details G Well Completion Details - Site 1 Test Well IC/TWl H Pumping Test Data Chronology of Construction - Desalter Test Well D/TW1/PW9 Mechanical Grading Analysis - Desalter Test Well D/TW1/PW9 K Well Completion Details - Desalter Test Well D/TW1/PW9 Development Notes - Desalter Test Well D/TW1/PW9 M Mission Basin Groundwater Levels GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority XV Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 GEOHYDROLOGIC INVESTIGATION OF THE LOWER SAN LUIS REY RIVER VALLEY, SAN DIEGO COUNTY, CALIFORNIA 1.0 EXECUTIVE SUMMARY This report summarizes the second phase (Phase 2) of a planned multi-phased study to evaluate the feasibility of Groundwater Storage and Recovery projects in the Lower San Luis Rey River Valley in northem San Diego County, California. The San Diego County Water Authority (SDCWA) is conducting this study as part of the 2030 Regional Water Facilities Master Plan. Two field investigation programs were identified under Phase 2 of the feasibility study with the purpose to collect information in the Lower San Luis Rey River Valley (Mission and Bonsall Groundwater Basins) that was necessary to fill geohydrologic data gaps identified during Phase 1. The SDCWA's principle goal is to determine technical and economic feasibility of the conjunctive-use project concepts identified in San Diego County Water Authority's April 2000 report entitled Phase 1 - Groundwater Storage and Recovery Feasibility Study: Lower San Luis Rey River Valley, and in the City of Oceanside's January 18, 2001, Proposition 13 - Groundwater Storage Proposal for the Mission Basin Groundwater Storage and Recovery Project grant application. The more immediate objectives of the field investigations included the following: 1. To further refine previous conceptual geohydrologic models of the Mission and Bonsall Basins, 2. To assess the usable storage capacity of the Mission Groundwater Basin for proposed extraction and recharge facility configurations, GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Water Authorily Geohydrologic Investigation - Lower San Luis Rey Rivcr Valley 31 -Aug-04 3. To investigate the nature and extent of confining conditions in the central and westem portions of the Mission Basin described by previous investigators, 4. To assess the artificial recharge and groundwater production potential of selected candidate sites; and 5. To evaluate the suitability of a candidate seawater intrusion barrier site in the Mission Basin narrows immediately east of Interstate 5. The objectives of the field investigation program were accomplished by: 1. Drilling 23 exploratory boreholes at candidate recharge and extraction sites to enable the collection of sediment cores and depth-specific soil samples for description and laboratory testing; 2. Completing downhoie geophysical borehole logs at each exploratory borehole location in support of the sediment core logs; 3. Completing surface geophysical surveys at selected sites in the Mission Basin to provide supplemental information regarding the subsurface configuration ofthe basin; 4. Constructing 13 groundwater monitoring wells (eight single completion wells and five nested wells) to enable the measurement of groundwater levels and the collection of groundwater samples for water quality testing; 5. Constructing two test wells for aquifer pumping tests to assess the characteristics of the aquifers (i.e. groundwater reservoir); and 6. Performing three aquifer pumping tests (one each on the two new test wells and one on an existing production well). The Mission and Bonsall Groundwater Basins are the westernmost basins within the Lower San Luis Rey River Valley. The basins are located within two relatively narrow, alluvium-filled valleys that are fianked by surrounding hills consisting of granitic rocks in the Bonsall Basin and easteriy Mission Basin, and by sedimentary rocks in central and western Mission Basin. The Mission Basin extends upstream from the Pacific Ocean to Bonsall Narrows. The Bonsall Basin GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 extends northeast from Bonsall Narrows to Montserate Narrows, a length of approximately eight miles. The maximum perennial yield (i.e. safe yield) of the Mission Basin has been estimated.lo range from 6,700 acre-ft/yr to 8,500 acre-ft/yr. Current average annual groundwater production within the Mission Basin, which is almost completely from City of Oceanside wells, is approximately 2,800 acre-ft/yr. The balance of surface and groundwater that is not utilized within the basin discharges to the Pacific Ocean through Mission Narrows at the west end of the basin. Summary of Investigation Sites As part of Phase 2 field investigations, fourteen sites were selected within the Mission Basin and one site was selected within the Bonsall Basin for drilling and testing. The Mission Basin sites are as follows: GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Site Location Potential Use 1 /Mission Narrows near State Highway 76 and Loretta Street, Oceanside Seawater Intrusion Barrier •2A Adjacent to San Luis Rey River near Foussat St., Oceanside Artificial Recharge/Ground water Extraction 2B N. Foussat St. and Shadowtree Dr., Oceanside Artificial Recharge/Groundwater Extraction 3B East end of Aspen St., Oceanside Artificial Recharge/Groundwater Extraction 3C Near Los Arbolitos and Aspen Streets, Oceanside Artificial Recharge/Groundwater Extraction 7A Near Frazee Rd. and Oleander Dr., Oceanside Artificial Recharge/Groundwater Extraction 9A Near Old Grove Dr. and Frazee Rd., Oceanside Artificial Recharge/Groundwater Extraction lOA Mission Ave. & Ranch Del Oro Dr., Oceanside Artificial Recharge/Groundwater Extraction 11 Near Douglas Dr. and Point Degada (Oceanside Municipal Golf Course) Artificial Recharge/Groundwater Extraction lie North of San Luis Rey River, near Whelan Lake, Oceanside Artificial Recharge/Groundwater Extraction 13 College Blvd. near Adams St., Oceanside Artificial Recharge/Groundwater Extraction 13A College Blvd at N. River Rd., Oceanside Artificial Recharge/Groundwater Extraction 32 Mission Ave & S. Foussat St., Oceanside Artificial Recharge/Groundwater Extraction Desalter 215 Fireside St., Oceanside Artificial Recharge/Groundwater Extraction GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 The Bonsall Basin Site (Site 26/27) is located near the intersection of State Highway 76 and Old Rt. 395 approximately 1,000 ft west of Interstate 15. This site is a potential artificial recharge/groundwater extraction site. Geology In general, unconsolidated alluvial sediments encountered within the Mission and Bonsall Basins are typical of sediments associated with a meandering stream system such as the San Luis Rey River. The alluvial sediments in the north-central portion of the basin (north of the Mission Basin Desalter Facility between Sites 3B and 9A) generally have relatively high percentages of silt and clay. Alluvial sediments along the southem margin of the Mission Basin consist of predominantly coarse-grained deposits (sand and gravel) indicative of stream channel deposition. The thickness of alluvial sediments is greater and the composition more coarse-grained along the southem margins of the basin as compared to the north. Two general types of bedrock were encountered during the field investigations: granitic bedrock in the Bonsall Basin and the eastem portion of the Mission Basin, and sedimentary bedrock of the La Jolla Group in the Mission Basin and the San Onofre Breccia in the westem Mission Basin. The granitic bedrock encountered in Phase 2 exploratory boreholes shows little weathering, suggesting that little secondary porosity is available to transmit water in this formation. The sandstone bedrock is water-bearing and constitutes the bedrock aquifer. The San Onofre Breccia is nearly impermeable and acts as a natural seawater barrier in the western Mission Basin. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily Geohydrologic Investigation - Lower San Lui,s Rey River Valley 31 -Aug-04 Geohvdrology The alluvial aquifer system in the Mission Basin was further delineated into shallow and deep aquifers based on differences in groundwater levels in depth-specific monitoring wells and differences in water level response during pumping tests. A semi-confining layer of clay and sandy clay separates the shallow and deep aquifer systems. This semi-confining layer extends beneath most of the western half of the Mission Basin. Groundwater within the Mission and Bonsall Basins occurs within the unconsolidated alluvium, semi-consolidated sedimentary bedrock, and to a lesser degree, cracks and weathered portions of the granitic bedrock that surrounds and underlies the alluvium. Groundwater is relatively shallow within both the Mission and Bonsall Basins, typically occurring at depths ranging from 10 to 20 ft bgs. Groundwater levels in the sedimentary bedrock aquifer are typically higher than the levels in the alluvial aquifer, which suggests the bedrock aquifer is confined. Groundwater flow is toward the west, in the same general direcdon as surface water flow within the San Luis Rey River. Recharge to the aquifer system in the Mission and Bonsall Basins occurs primarily from seepage beneath the San Luis Rey River. Groundwater levels in Desalter Wells OW-1 and OW-1 (40 East), which are both perforated within the shallow alluvial aquifer, rise noticeably during periods of increased precipitation and corresponding increased stream flow along the San Luis Rey River. Similarly, groundwater levels measured in monitoring wells in the unconfined portion of northeastem Mission Basin also rise during the late winter and spring months in response to precipitation during this part of the year. Although some recharge to the alluvial aquifer is expected from direct infiltration of precipitation on the land surface, the San Luis Rey River is likely the predominant source of replenishment water to this aquifer. The shallow alluvial aquifer is relatively permeable in the northeastem Mission Basin, with transmissivities ranging from 70,000 to 130,000 gpd/ft. In the central Mission Basin, the higher GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 percentage of fine sand and silt suggests that transmissivities of this aquifer are lower. The underlying deep alluvial aquifer is very permeable, with transmissivities ranging from 138,000 to 205,000 gpd/ft. The sedimentary bedrock aquifer does not appear to be permeable in the vicinity ofthe Mission Basin Desalter site; however, further testing is required to assess the permeability of this aquifer elsewhere in the Mission Basin. Groundwater Oualitv The groundwater quality of the alluvial aquifer within some areas of the Mission Basin does not show any predominant water type, although water from the westem portion of the .basin is relatively enriched in chloride relative to other anions. Groundwater quality in the Mission Basin is impaired with relatively high concentrations of total dissolved solids (TDS), chloride and sulfate. TDS concentrations typically range between 1,500 and 1,880 milligrams per liter (mg/L). Chloride and sulfate concentrations typically exceed the Department of Health and Safety's secondary maximum contaminant level (MCL) for these constituents; the secondary MCL is 250 mg/L for both constituents. • The high concentration of TDS is reportedly due to lateral and vertical migration of saline water from surrounding marine sedimentary formations, remnants of historical seawater intrusion, and long-term basin recharge with poor quality irrigation-return water. Seawater intmsion does not appear to currently be an issue within the basin. The groundwater flow direction within the basin has been toward the ocean at least since the early 1970s and TDS and chloride concentrations at Site 1 (nearest the Pacific Ocean) are similar to those detected in monitoring wells inland from this site. The groundwater quality of the Mission Basin sedimentary bedrock aquifer is enriched in sodium or potassium relative to the other cations, which is slightly different than the water quality of the GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 3! -Aug-04 alluvial aquifer. TDS concentrations in the bedrock aquifer groundwater are generally lower than the alluvial aquifer groundwater it is highly variable, ranging between 480 and 1,400 mg/L. Conclusions and Recommendations In terms of groundwater production, the most favorable locadons within the Mission Basin for high capacity production wells are those in the southem portions of the basin where the alluvial sediments are characterized by high permeability sand and gravel and the thickness of these sediments is the greatest. Pumping wells in these areas could produce as much as 2,000 gpm of instantaneous flow. Furthermore, pumping wells in the southern portion of the basin would have the least impact on surface water flow within the San Luis Rey River because they are furthest from the river. The most favorable locations for future production wells include the areas at or in the vicinity of investigation Sites 32, lOA and the Oceanside Desalter site. Based on existing data, the sedimentary bedrock aquifer in the Mission Basin does not appear to be a significant source of groundwater to future production wells. However, the existing data is specific lo one area of the basin and, given the relatively permeable sediments observed in cores in other areas, further pumping tests within the bedrock aquifer in other portions of the basin are warranted. Artificial recharge via surface spreading basins is likely feasible in many areas of the Mission Groundwater Basin as long as current groundwater levels can be lowered to create the necessary subsurface storage space. The high percentage of relatively permeable alluvial sediments in the southem portions of the basin is conducive to the downward percolation of surface water. Furthermore, no laterally extensive impermeable silt and/or clay layers were identified that would inhibit percolation of surface water. The most favorable sites for artificial recharge using surface spreading basins are Sites 2A, lOA, 13A and the Desalter site. However, the feasibility GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 of artificial recharge using surface spreading basins should be confirmed through a pilot-testing program (see Section 10). Artificial recharge via injection wells may be feasible within the alluvial aquifers in some portions of the westem part of the Mission Basin. However, further testing is required to verify this conclusion. Conditions that appear to be most favorable for injecdon wells occur at Sites 1, 7A, 9A, 11, 32 and the Desalter site. Based on existing data, the potential for artificial recharge of the bedrock aquifer system via injection wells appears to be low. Pumping lest data and laboratory analysis of samples suggest that the permeability of the sedimentary bedrock is relatively low and would not accept large volumes of water. However, given the relative lack of data regarding the lateral variation in bedrock permeability, further testing in other areas of the basin would be beneficial to verify this conclusion. Potential geohydrologic constraints that should be considered prior to implementation of a conjunctive use program in the Mission Groundwater Basin include: • Potential environmental impacts to the riparian habitat in the vicinity of the San Luis Rey River from lowering of groundwater levels. Potential for land surface subsidence due to groundwater withdrawal during periods when groundwater production exceeds inflow from natural and artificial recharge, and • Potential for liquefaction during periods of high groundwater levels during periods when natural and artificial recharge exceeds groundwater production. Future lowering of the groundwater level in the Mission Basin as a result of conjunctive use activities would have to be managed to avoid impacts to the riparian habitat along the Sari Luis Rey River. Conceptually, artificial recharge could be maximized at the sites along the San Luis GEOSCIENCE Support Services, hic. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Rey River (i.e. Site 2A; the Desalter Site, Site 3B, Site 3C, Site 9A, Site 7A, and Site 13A) while focusing production at sites in the southem pordon of the basin that are the furthest away from the river but have the greatest potential for groundwater production (Sites lOA and 32). In so doing, excessive groundwater level lowering directly beneath the river could be minimized. Land surface subsidence is not expected to be a significant geohydrologic constraint to conjunctive use projects in the Mission Basin because the conditions that cause subsidence (thick layers of subsurface clay in areas with excessive groundwater level drawdown) do not exist and would not be created by future operation of the groundwater basin. Because existing and proposed groundwater level conditions in the Mission Basin are susceptible to liquefaction, further investigation is recommended to collect the data necessary to evaluate this constraint. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 10 Geohydrologic Investigation - Lower San Luis Rey Rivcr Valley 31-Aug-04 2.0 INTRODUCTION The San Diego County Water Authority (SDCWA), in conjuncdon with the City of Oceanside, is conducdng a phased evaluation to study the feasibility of Groundwater Storage and Recovery projects in the Lower San Luis Rey River Valley in northem San Diego County, Califomia. The SDCWA is performing this study as part of their 2030 Regional Water Facilities Master Plan (ASL Consulting Engineers [ASL], 2000). Initially, several groundwater basins within the Lower San Luis Rey River watershed were considered for future water management planning. The SDCWA conducted a groundwater feasibility study as part of its Emergency Storage Project study in 1995 (NBS Lowry, 1994). The findings suggested a potential for a carryover (conjunctive-use) storage project in the Mission Basin in the Lower San Luis Rey River Valley. The Lower San Luis Rey River Valley had also been identified by the SDCWA as offering the greatest potential for a conjunctive-use project because previous studies have indicated the following: • There is a potential for an estimated 39,000 acre-ft of groundwater storage to be developed in the Bonsall and Mission Basins, • Groundwater storage and recovery projects developed in the Bonsall and Mission Basins would provide the opportunity to purchase imported water at a discount, The Bonsall and Mission Basins could provide addifional increment of treated water within the SDCWA service area, • A portion of the region's treated water demand could be enhanced by replenished groundwater in the Bonsall and Mission Basins, reducing the demand on the region's imported water system and surface water resources, • Groundwater storage and recovery projects in the Bonsall and Mission Basins could potentially capture additional mnoff and thereby reduce the need to purchase discounted imported water for artificial replenishment. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 11 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 This report provides a summary of data collecfion acfivifies associated with the second phase (Phase 2) of the Groundwater Storage and Recovery Feasibility Study for the Mission and Bonsall Groundwater Basins in the Lower San Luis Rey River Valley (see Figures 1 and 2). 2.1 Background and Previous Investigations The development of groundwater storage and recovery programs requires comprehensive information of the project area, such as geohydrologic characteristics, exisfing groundwater quantity and quality, imported and surface recharge water quality, exisfing water system infrastmcture, and permitfing and environmental issues. In order to systemafically compile and evaluate this information in a comprehensive and financially feasible manner, SDCWA has planned this feasibility evaluation as a phased study. Phase 1 of the groundwater storage and recovery feasibility study was completed in 2000 by ASL Consulting Engineers (ASL, 2000) and consisted primarily of a "desktop" study to evaluate and/or develop the following: Existing water resources data, A geographic information system (GIS) for the display of project features and data, Hydrogeology, including existing and planned groundwater use, Existing water systems, Altemative groundwater storage and recovery projects, Costs and benefits including a ranking criteria for groundwater storage and recovery project concepts, and A recommended scope of work for Phase 2 activifies. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 12 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 As a result of Phase 1, Phase 2A was implemented to develop additional information necessary to support future field investigafion activities. The Phase 2A scope of work included the following general tasks: • Performance of a basin wide well survey, • Identification, evaluation and ranking of alternative extraction well and recharge sites, • Development of a stakeholder database for use in public outreach efforts, • • Evaluafion of permitfing and access requirements at potenfial recharge and extraction well sites, • Evaluafion of potential environmental contamination impacts to selected groundwater recharge and extracfion sites. Preparation of a Phase 2B field invesfigation report, < Development of recommended Phase 2B work acfivifies, and Development of a Phase 2A technical memorandum summarizing the findings of this portion ofthe feasibility study. From the Phase 2A work, fourteen parcels in the Mission Basin were selected for further investigation in Phase 2B conducted by Tetra Tech, Inc. These parcels were given the names (Site) 1, 2A, 2B, 3B, 3C, 7A, 9A, lOA, 11, IIC, 13, 13A, 32 and the Oceanside Desalter (see Figure 3). All Mission Basin sites selected for field investigation in Phase 2B, except Site 32, are owned by the City of Oceanside. Site 32 is owned by the City of Carlsbad. At least one exploratory boring was completed at each site during Phase 2B (conducted in 2002) except at Site lie. Monitoring wells were installed at Sites 1, 2B, 3B, 7A, lOA, 13A, and 32. A six-inch diameter test well and a four-inch diameter monitoring well were also constructed at Site 1 during Phase 2B. In addition to field investigations, development of a groundwater flow model GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 13 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 was specified to help assess the feasibility and affects of different project- altematives on groundwater levels and environmental issues. 2.2 Data Gaps Identified From Phase 1 To verify the feasibility of each project concept defined during Phase 1, additional geohydrologic data was required in key areas of the Mission and Bonsall Groundwater Basins. Specifically, the following is a generalized list of data that was needed to improve the overall understanding of aquifer characteristics under existing and project conditions: • Verification of aquifer properties and hydraulic gradients of the alluvial aquifers in the Mission and Bonsall Basins; • Assessment of near-surface aquifer and soil properfies (i.e. water levels, groundwater quality, infiltration rates); • Detailed aquifer geometry (depth to bedrock) and geohydrologic condifions; • Evaluation of groundwater chemistry and basin geochemistry to detennine compafibility with proposed reclaimed and imported water; • Assessment of longer-term (up to 30 days) performance, efficiency and recovery potential of test wells installed at proposed recharge/extracfion sites; • Create an inventory of known contaminated sites that could be affected by groundwater storage and recovery projects; • Conduct an updated inventory of existing water wells and groundwater use in the Mission and Bonsall basins; and • Further evaluation of environmental impacts in project concept areas. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 14 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 2.3 Data Gaps Identified During Phase 2B A fundamental assumpfion that govemed the Phase 2B field investigafions was that the sedimentary bedrock (the La Jolla Group) did not yield significant quanfifies of water to wells and, thus, was not a focus of investigation. Although many of the boreholes were advanced into what was thought to be sediments of the La Jolla Group, the depth, aquifer characterisfics and groundwater quality of the sediments were not investigated in detail. During drilling of Phase 2B boreholes, however, visual inspection of the bedrock sediments suggested that the bedrock formation may be sufficiendy permeable to yield water to wells or accept water via injection wells. The total depths and sampling intervals of exploratory borings and monitoring wells drilled as part of Phase 2C were designed to more fully investigate the bedrock aquifer. 2,4 Phase 2C Purpose and Scope The overall purpose of the Phase 2C field investigation was to collect the data necessary to: • Evaluate the geohydrologic characteristics and groundwater quality of the upper portions of sandstone bedrock underlying the younger unconsolidated alluvial deposits in the Mission Basin, • Evaluate the physical characteristics of hydrostratigraphic units in the unconsolidated alluvial deposits and upper portions of the sandstone bedrock in the area of the Mission Basin Desalter where the City of Oceanside is operating three (3) large-diameter municipal production wells, • Determine the stratigraphic units that the exisfing City of Oceanside producfion wells (Nos. 1, 2 and 3) are perforated within at the Mission Basin Desalter Site, • Refine the understanding of the artificial recharge potenfial of the alluvial aquifers in the Mission and Bonsall basins, GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 15 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 Refine the Mission Basin groundwater flow and transport model developed in Phase 2B and re-evaluate the feasibility of a conjuncfive-use project in the Mission Basin, and • Develop a pilot test program, if warranted. The scope of work for the Phase 2C program included a comprehensive drilling, sampling and testing program that was conducted from August 2003 to Febmary 2004 at four sites in the Mission Basin and one site in the Bonsall Basin (see Figures 3 and 4). The general types of data collected during the drilling program included soil/bedrock lithology, soil/bedrock physical properties, groundwater quality and alluviunVbedrock aquifer properties. A detailed description of the drilling, sampling and tesfing programs is provided in Secfion 7. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 16 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 3.0 DESCRIPTION OF AREA 3.1 Project Location The Project Area under invesfigation is located within the drainage of the Lower San Luis Rey River Valley in the northem part of San Diego County, Califomia (see Figure 1). Specifically, the Project Area is defined by the boundaries of the Mission and Bonsall Groundwater Basins as shown on Figure 2. This invesUgational area of the watershed lies west of the Palomar Mountains near the town of Bonsall and extends to the Pacific Ocean in the City of Oceanside. Riverside County and Marine Corps Base Camp Pendleton form the boundary to the north and northwest, respecfively. The cifies of Vista and Escondido are located along the southem limits of the Project Area. 3.L1 Mission Basin The Mission Basin is the westemmost basin within the San Luis Rey River watershed. Encompassing the City of Oceanside, the basin extends upstream from the Pacific Ocean approximately eight miles to the Bonsall Narrows, a narrow rock gorge in the San Luis Rey River approximately two miles south of Bonsall (see Figure 2). 3.1.2 Bonsall Basin From the Bonsall Narrows, the Bonsall Basin continues east and upstream approximately 9 miles along the San Luis Rey River. This basin generally lies within an unincorporated area of northem San Diego County and extends eastward to the Monserate Narrows, a constriction in the San Luis Rey River located approximately one mile east of Interstate 15 (see Figure 2). GEOSCIENCE Support Services, Inc. Tetra Tcch/San Diego County Water Authority 17 Geohydrologic Investigation - Lower San Luis Rey River Valley , 31 -Aug-04 3.2 Topography and Physiography The Project Area is located within the Peninsular Ranges geomorphic province of Southem Califomia. The Peninsular Ranges are characterized by a relatively narrow Pacific Coastal Plain on the west and moderate to steep, northwesterly trending mountains and narrow, interconnected valleys on the east (see Figure 1; PCR, 2002). Major drainage systems generally traverse the province in an east/west direcfion. These include, from north to south, the Santa Margarita, San Luis Rey, and San Dieguito rivers (Ellis and Lee, 1919). Each of these watersheds typically consists of. a series of shallow, elongated alluvium-filled basins separated at either end by steep-walled gorges (DWR, 1958). The Project Area encompasses the two westemmost alluvial basins, idenfified herein as the Mission and Bonsall Basins of the Lower San Luis Rey River. The Mission and Bonsall basins are located within two relafively narrow (less than 1 mile wide), alluvium-filled valleys that are flanked by both mesa-like, and rolling hills of sedimentary rocks on the west (lower and middle reaches of the Mission Basin), and steep-walled igneous rocks on the east (upper reaches of Mission Basin and all of Bonsall Basin). Surface elevafions of the valley fill in the Mission Basin ranges from sea level to approximately 120 ft amsl at the east end of the basin (Bonsall Narrows). Surface elevations in the Bonsall Basin range from approximately 120 ft amsl in the westem area to approximately 300 ft amsl at the eastern end of the basin (Monserat Narrows). The westem ridges that characterize the Pacific Coastal Plain in the Mission Basin rise to a maximum elevafion of approximately 300 ft amsl. The maximum elevation ofthe Peninsular Ranges in the area of Bonsall Narrows is approximately 1,458 ft amsl at Lancaster Mountain (eastem boundary of Bonsall Basin). 3.3 Climatological Characteristics The climate of the Lower San Luis Rey River Valley is Mediterranean, being characterized by hot dry summers and relatively cool rainy winters (DWR, 1956). The average annual temperature in the Project Area is approximately 63 "F, although daytime high temperatures GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 18 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 during the summer months can be over 100 T and night time lows during the winter months can reach approximately 20 "F. Temperature data collected from the Oceanside Marina and Vista areas indicate that the mean monthly temperature ranges from 49.6 °F to 78.5 "F. Temperature extremes during the period between 1953 and 2003 vary from a record low of 20 °F to a high of 108 T (Westem Regional Climate Center [WRCC], 2003). Precipitafion within the Lower San Luis Rey River watershed occurs primarily during the four-month period from December through March (WRCC, 2003). Precipitation generally occurs in the form of rainfall within the Project Area. Precipitation records collected from two precipitation stations are shown on Figure 5. In general, average annual precipitafion in the Project Area increases with increasing elevafion landward from the Pacific coast (RECON, 1996). Mean anntial precipitation ranges from less than 10 inches at the Oceanside Marina (westemmost Mission Basin) to greater than 15 inches in the highest elevafions of the Bonsall Basin (WRCC, 2003). Esfimated evaporation rates for the lower San Luis Rey River watershed was based on pan evaporation records from Lake O'Neil, which is located approximately 5 miles north of the Mission Basin within the Santa Margarita River Valley. Average annual evaporation records during the period between 1953 and 1954 are summarized in Table 1. The average annual pan evaporafion during this period was 62.22 inches (DWR, 1956). Daily potential evapotranspiration (PET) for the upper Santa Margarita River Valley is 55.5 inches/yr as reported by Crippen (1965). By subtracting the average annual precipitation rates for the Lower San Luis Rey River Valley from the PET rate, the actual evapotranspirafion rate (ET) is estimated to range from approximately 41 to 43 inches/yr. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 19 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 4.0 REGIONAL GEOLOGIC SETTING The regional geology of the San Luis Rey River watershed area is largely a funcfion of the tectonic history of the Peninsular Range Province. The Peninsular Ranges are a northwest-southeast oriented complex of igneous and metamorphic rocks, which includes the Southern California batholith, a granitic bedrock complex that forms the mountains and hills to the east of the Project Area (Norris and Webb, 1990). During the Mesozoic (144 to 245 million years before present), sea floor sediments were being subducted off the coast of Califomia, forming magma at depth, which resulted in the emplacement of the Southem Califomia Batholith, including the Upper Cretaceous (65 million years before present) Bonsall Tonalite, a granitic formation which outcrops in the eastem portion of the Project Area (see Figure 6). The tectonic processes of the Peninsular Ranges changed during the Cenozoic (present to 65 million years before present), when subducfion ceased, and transform faulting (i.e. lateral shear) began on the San Andreas Fault system (PCR, 2002). As a result, horizontal mofion began in this region between 25 and 20 million years before present and created the strike-slip faults that characterize the present landscape (Atwater, 1970). The rocks of the Peninsular Ranges have weathered into westward sloping hills, and form the basement complex onto which the sedimentary formafions of Terfiary age (5 to 65 million years before present) of the Pacific Coastal Plain were deposited (Izbicki, 1985a). The period between the end of the Pliocene epoch to the Pleistocene (approximately 1.8 to 5 million years before present) was characterized by large-scale climatic episodes (i.e. glacial events) coupled with episodes of tectonic uplifting that formed the present landscape of the Pacific Coastal Plain of Southern Califomia (Ellis and Lee, 1919; Nofi-is and Webb, 1990). The series of wave-cut terraces along the coastal margin were formed by fluctuafing sea levels during glacial events, and during events of rapid vertical movements along the coasUine (Norris and Webb, 1990). GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Waler Authority 20 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 During Pleistocene glacial stages, the lowered sea level forced streams crossing the terraces to cut deep gorges, which is exemplified by the canyon located at the west end of the Mission Basin (Norris and Webb, 1990). As postglacial sea levels rose, downcutfing of the San Luis Rey River channel gave way to the deposifion of alluvial sediments in the Mission Basin (Izbicki, 1985a). These relafively thick sequences of alluvium and river-channel deposits typically consist of permeable gravel and sand that are locally confined by overlying sequences of fine sand, silt and clay (Moreland, 1974). 4.1 Geologic Structure The Lower San Luis Rey River watershed is situated between two major northwest-trending faults, identified as the Elsinore Fault Zone and Ingle wood/Rose Canyon Fault Zone. The most prominent fault is the right-slip Elsinore Fault Zone. The Elsinore Fault is associated with movement along the greater San Andreas Fault, and is located approximately 13 miles to-the northeast of Bonsall (Ziony et al., 1974; Norris and Webb, 1990). The Inglewood/Rose Canyon fault is located approximately four miles off the coast of Oceanside. The area of the Lower San Luis Rey River watershed between the Elsinore Fault and the Inglewood/Rose Canyon Fault has undergone relatively little faulfing. Geologic mapping by Ziony et al. (1974), Izbicki (1985a) and Tan and Kennedy (1996) idenfified two unnamed faults within the San Onofre Breccia located at the western end of the Mission Basin (see Figure 6). These faults have a similar northwest-southeast trend as do the primary side canyons in this area, but have limited lateral extent at the surface. According to Jennings (1994), offshore faults associated with the Rose Canyon system are early quaternary in age. As such, faulfing in the area has not likely impacted the alluvial strafigraphy (which is recent in age) and, based on observation of groundwater contour maps of the area, does not appear to impact groundwater flow. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 21 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 4.2 Stratigraphy The principal geologic units that occur within the Lower San Luis Rey River Valley (shown on Figure 6) include (from oldest to youngest): . Bonsall Tonalite (Kt) . The La Jolla Group (Tlj) • The San Onofre Breccia (Tso) • Unnamed Marine Terrace Deposits (Qt) • Alluvium (Qal) The Bonsall Tonalite is an upper Mesozoic age (approximately 144 to 65 million years before present) granitic rock that underlies the Bonsall Basin and the eastem porfion of the Mission Basin. Outcrops of the tonalite are moderately to intensely weathered, which has produced a veneer of coUuvial deposits and surficial soils overlying the consolidated bedrock. The top of the unweathered granitic basement rock is considered the effecfive base of fresh water aquifers; however, some groundwater flow may occur in the secondary porosity features (i.e. fractures, joints, and formafion contacts) in the tonalite (Moreland, 1974). Semi-consolidated to consolidated sedimentary rocks of the Eocene age (53.5 million years before present) La Jolla Group surround and underlie the younger unconsolidated Quatemary sediments that fill the San Luis Rey River Valley in the Mission Basin. The La Jolla Group has been divided into three members in San Diego County: The Del Mar, Torrey, and the Rose Canyon members. The La Jolla Group is described as a transgressive-regressive triplet of open marine, bar-nearshore shelf, and lagoon facies along a steadily submerging coasfiine (Gasfil and Higley, 1977). These rocks consist primarily of light-colored, fine to coarse-grained sandstone with interbedded siltstone and claystone (Izbicki, 1985a). In general, the sandstones have relatively low permeability but are water-bearing. The siltstone, claystone and shale units are GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 22 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 relafively low in permeability (DWR, 1956). The maximum thickness of the La Jolla Group in the Lower San Luis Rey River Valley is esfimated to be approximately 1,650 ft (DWR, 1967). A younger unit of Tertiary rocks, referred to as the San Onofre Breccia, is also found in the Lower San Luis Rey River Valley. This formation outcrops in the hills west of the La Jolla Group exposures in the Mission Basin. The San Onofre Breccia is of Miocene age (approximately 23.5 million years before present) and consists of angular, broken rock fragments that range in size from less than one inch to several ft in diameter (Ellis and Lee, 1919). The rock fragments are derived from a series of long bedrock ridges, extending from near Oceanside to Santa Monica, that are now submerged off the coasfiine (Norris and Webb, 1990). The San Onofre Breccia is relatively impermeable, forming a natural seawater barrier beneath the alluvial aquifers of the Mission Basin (Izbicki, 1985a). Overlying the San Onofre Breccia are unnamed marine terrace deposits of Pleistocene age (approximately 1.8 million years before present). These terrace deposits consist of reddish brown, poorly bedded sandstone, siltstone and conglomerate rocks (Tan and Kennedy, 1996). The terraces were originally formed during a series of subsequent events of marine deposifion, and then subjected to wave-cut erosion during episodes of sea level regression and/or regional uplifting. Each terrace has undergone some degree of stream erosion, which contributed to the surface irregularities conspicuous in the present landscape (Ellis and Lee, 1919). Unconsolidated alluvial sediments of Holocene age (approximately 10 thousand years ago to present) and Quatemary age at depth occur within all of the flood plains and tributary stream channels of the Lower San Luis Rey River Valley. Driller's logs of wells located in the Mission Basin indicate that ancient streams incised portions of the underlying Tertiary bedrock as much as 200 ft below the level of the present valley floor. The inferred topography of the sedimentary basement underlying the Mission Basin alluvium is shown on Figure 7. The period of river down cutting was followed by (and continues today) the deposifion of sediments presumably derived from erosion of metasediment and granitic rocks of the Peninsular Range Province. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 23 Geohydrologic Investigation - Lower San Luis Rey River Valley - 31-Aug-04 Sediments deposited by the San Luis Rey River included both channel fill (sand and gravel) and flood plain deposits (silt and sand mixtures with isolated clay layers). GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 24 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 5.0 REGIONAL GEOHYDROLOGIC SETTING The Lower San Luis Rey River Valley is located in the San Diego Hydrologic Basin, which occupies approximately 3,900 square miles of San Diego County and portions of Orange and Riverside Counfies (PCR, 2002). The San Luis Rey River drains an approximate 565 square mile portion of the San Diego Hydrologic Unit (Skrivan, 1976) and contains the following five major alluvial groundwater basins (listed in order from highest to lowest elevafion): Warner Basin, Pauma Basin, Pala Basin, Bonsall Basin, and Mission Basin. The focus of this report is the Mission, and to a lesser extent, the Bonsall Groundwater Basins (see Figure 2). The groundwater basins in the Lower San Luis Rey River Valley, including the Mission Basin, have historically been defined as the groundwater reservoirs within the unconsolidated alluvial sediments. The bottom of the Mission Groundwater Basin has been assumed to be the contact between the unconsolidated alluvium and the sedimentary bedrock of the La Jolla Group (see Figures 6 and 7). Estimates of groundwater storage capacity of the Mission Basin have previously been based upon an esfimated average storage coefficient for the alluvium and the estimated volume of the unconsolidated alluvium deposited above the underlying sedimentary bedrock. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 25 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 5.1 Surface Water The San Luis Rey River originates in northem San Diego County near Mount Palomar where it flows westward and drains into Lake Henshaw. Major tributaries of the river consist of the following: Agua Caliente Creek, Buena Vista Creek, West Fork San Luis Rey River, Pauma Creek, Keys Canyon Creek, Moosa Creek, and Pilgrim Creek (see Figure 1). Surface water flow in the Lower San Luis Rey River has been regulated since 1923 at the Lake Henshaw Reservoir (Izbicki, 1985a). In general, the San Luis Rey River is an ephemeral river, characterized by peak flows occurring during the months of December through March and low to no flow from April through November (Izbicki, 1985a; Tetra Tech, 2001). However, the river flows at the surface perennially in much of the Mission Basin and in the westem and central portions of the Bonsall Basin due to changes in groundwater use during the past three decades (RECON, 1996). In October 1912, one permanent gaging stafion (11042000) was estabhshed by the United States Geological Survey (USGS) in the canyon at the west end of the Mission Basin (Mission Narrows) (see Figure 5). Another station (11041000") was installed in October 1929 at Bonsall Narrows, and a third stafion (11040000^) was added in October 1937 at Monserate Narrows (see Figure 5) (USGS, 2004). Data from these three gaging stafions make up the long-term stream flow data in the Lower San Luis Rey River watershed. Average annual discharge at these three gauging stations was summarized by Izbicki (1985a) as 7,200 acre-ft at the Monserate Narrows stafion, 16,810 acre-ft al the Bonsall Narrows station and 16,160 acre-ft at the Mission Narrows station. Data records collected at the Mission Narrows stafion indicate that the average annual discharge rate has increased to slightly greater than 36,000 acre-ft since 1982 (USGS, 2004). ' Gauging station 11041000 was destroyed by a flood on 12-Mar-1980 (Izbicki, 1985a). ^ Use of station 11040000 was discontinued in 1986. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 26 Geohydrologic Investigation - Lower San Luis Rey River Valley ,31 -Aug-04 5.2 Groundwater Groundwater within the Mission and Bonsall Groundwater Basins occurs within the unconsolidated alluvium, semi-consolidated sedimentary bedrock, and to a lesser degree, the granitic bedrock within and surrounding the basins (Izbicki, 1985a). For purposes of this report, the individual groundwater reservoirs within the basins have been categorized as the alluvial aquifer and the bedrock aquifer. 5.2,1 Aquifer Systems The primary groundwater reservoir (i.e. aquifer) within the Lower San Luis Rey River Valley is the unconsolidated alluvium, which overlies bedrock formafions in the Mission and Bonsall Basins. This aquifer extends throughout Mission Basin, thinning to the east and north and thickening to the south and west, where alluvial thickness exceeds 200 ft. Permeable zones within the central and western portions ofthe basin are overlain with sequences of fine sand, silt and clay that locally confine the groundwater (Moreland, 1974; Izbicki, 1985a; NBS Lowry, 1993). The alluvial aquifer also extends throughout the Bonsall Basin with an average thickness of approximately 80 ft (Moreland, 1974). Detailed discussions of the alluvial aquifer systems of the Mission and Bonsall Groundwater Basins, based on data collected from the Phase 2 field investigations, are provided in Sections 8 and 9, respectively. The sedimentary units of the La Jolla Group underlie the majority of the Mission Basin and constitute the bedrock aquifer in this area. Prior to the Phase 2 investigations described in Sections 7 and 8, little was known of the geohydrologic characteristics of the sedimentary rocks of the La Jolla Group. Existing data from wells completed in the sandstone of the La Jolla Group (in areas outside of the Mission Basin) indicated an average discharge rate of 20 gpm, and specific capacifies of approximately 0.4 gpm/ft of drawdown (Izbicki, 1985a). A discussion of the La Jolla Group sediments and the bedrock aquifer based on the findings of the Phase 2 invesfigations is presented in Sections 8.1.2 and 8.2.3. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 27 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 At the westem end of the Mission Basin, the well-indurated nature of the San Onofre Breccia limits its ability to yield significant quanfities of water to wells. Moreover, except for times when heavy pumping lowered the groundwater elevafion of the Mission Basin alluvial aquifer below sea level, the breccia acts as a seawater barrier along the basin's westem margin (DWR, 1958; Izbicki, 1985a). 5.2.2 Groundwater Flow Groundwater flows by gravity drainage from areas of high elevafion (release point below Lake Henshaw Dam and downstream side canyons) into each subsequent groundwater basin that make up the San Luis Rey River watershed. Generally, groundwater flow within the Mission and Bonsall Basins is from the northeast towards the southwest (see Figure 8), following the general direcfion ofthe San Luis Rey River (Moreland, 1974; Izbicki, 1985a). Groundwater flow within the granitic rocks in the eastem portion of the Lower San Luis Rey River Valley is limited, and is probably confined to the upper 50 to 100 ft based upon the degree of fracturing and weathering observed in boreholes (DWR, 1967; Izbicki, 1985a). The direcfion of groundwater flow within the granitic bedrock aquifer of the Bonsall Basin has not been determined. 5.2.3 Historical Groundwater Levels Prior to the development of the Lower San Luis Rey River Valley, groundwater levels in the area were likely very shallow throughout the Mission and Bonsall Basins. Groundwater pumping increased substantially in the 1940s as a result of agricultural development of the area. Between 1950 and 1965, groundwater levels in westem Mission Basin dropped to as much as 43 ft below sea level (see Figure 8; DWR, 1984). The lowered groundwater levels resulted in seawater intmsion for a distance of two to six miles inland from the coast (USGS, 1976), and impairment GEOSCIENCE Support Services, Ihc. Tetra Tech/San Diego County Water Authority 28 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 of the groundwater quality of the area. Between 1965 and 1970, groundwater levels recovered when pumping from the basin decreased as agricultural land use was replaced by urban development and the source of water supply shifted from groundwater to imported water. By 1970, groundwater levels in the Mission Basin averaged between 3 to 20 ft bgs, which was near or higher than pre-1940s groundwater levels (Izbicki, 1985a). Historical groundwater levels for the Bonsall Basin are not available. 5.2.4 Aquifer Characteristics 5.2.4.1 Alluvial Aquifer Previous studies of the Mission Basin have reported alluvial aquifer transmissivities ranging from 50,000 to 300,000 gallons per day per foot (gpd/ft), generally decreasing downstream from east to west (Moreland, 1974). Likewise, esfimated hydraulic conducfivity ranges from 500 to 2,000 gallons per day per square foot (gpd/ft), with wells located in the eastem portion exhibiting the highest values (Moreland, 1974). These esfimates have been verified from pumping tests conducted on wells operated by the City of Oceanside in the eastem portion (North River Road well field) and in the central portion of the basin (Oceanside Desalter Facility) (Geopacifica, 1995). In comparison, an aquifer performance test conducted at the Oceanside Desalter Facility in August 1991 indicated that the alluvial aquifer in the central porfion of the basin has an estimated transmissivity of 140,500 gpd/ft, hydraulic conducfivity of 2,300 gpd/ft , and a storafivity value of 0.00051 (City of Oceanside, 1991). In the Bonsall Basin, aquifer hydraulic conductivity has been esfimated to range from 1,000 to 2,000 gpd/ ft^ (Moreland, 1974), although litfie pumping test data is available for this basin. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority • 29 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 5.2.4.2 Bedrock Aquifer The granitic bedrock (Tonalite) is comprised primarily of plagioclase, biotite and homblende with minor amounts of quartz, which has been reported to exist in a highly fractured and weathered state up to 3,000 ft bgs within the vicinity of the Bonsall Basin (Geotechnical Consultants, 1990; L.R. Burzell, 1999). Transmissivity values were reported by L.R. Burzell Consulting Services (1999) for five pumping wells that are perforated at various depths within the Bonsall Tonalite in a well field located a few miles northwest of the Bonsall Narrows. The combined transmissivity for the five wells was reported to range from a minimum of approximately 37,000 gpd/ft to a maximum of 175,000 gpd/ft. Transmissivity values are not available from wells completed in the La Jolla Group or the San Onofre Breccia within the Mission Basin. However, Izbicki (1985a) reported discharge rates as much as 50 gallons per minute (gpm) in wells completed within the La Jolla Group formafion outside ofthe Mission Basin. 5.2.5 Mission Basin Groundwater Budget 5.2.5.1 Estimates of Groundwater Recharge Groundwater recharge is the total amount of water that reaches the aquifer (i.e. groundwater reservoir) through natural processes, such as deep percolafion of precipitation falling on the land surface and infiltrafion beneath flowing stream channels. The alluvial aquifer of the Lower San Luis Rey River Valley is recharged primarily from infiltration of stream flow from the San Luis Rey River and Pilgrim Creek (Izbicki, 1985a; NBS Lowry, 1993). Other recharge sources include infiltrafion of precipitation, imported irrigation water in the upland area, urban and agricultural runoff, and groundwater underflow from the Bonsall Basin into the Mission Basin (NBS Lowry, 1993; Welch, 1996). In addition, as much as 500 acre-ft of reclaimed water is recharged into the Bonsall Basin each year (NBS Lowry, 1992). GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 30 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Groundwater throughout the majority of the Mission Basin alluvial aquifer exists in an unconfmed state. However, in the central and westem porfion of the basin, the aquifer becomes verfically separated by an underlying semi-confined to confined alluvial aquifer (Izbicki, 1985a; NBS Lowry, 1993). The upper unconfined aquifer receives recharge from surface infiltration, while the lower aquifer is presumably recharged from infiltration in forebay areas of the Mission Basin, and also from interflow through fractured granitic rocks on the sides and upstream portions ofthe basin (NBS Lowry, 1992; Welch, 1996). Several esfimates of recharge to the Lower San Luis Rey River alluvial aquifer system have been previously reported. Moreland (1974) esfimated average annual recharge in the Mission Basin alluvial aquifer at 6,700 acre-ft/yr. NBS Lowry (1993) estimated the mean annual recharge from the San Luis Rey River and other sources to the Mission Basin to be 8,500 acre-ft/yr during the period between 1975 and 1990. The NBS Lowry (1993) estimate included the following recharge contribution sources: Direct Percolafion of Precipitafion (800 acre-ft/yr); • Percolafion of Stream flow from the San Luis Rey River and Pilgrim Creek (4,700 acre-ft/yr); Percolation from Applied Landscape Irrigafion (1,000 acre-ft/yr); • Recharge from Sepfic Tanks and Municipal Wastewater (600 acre-ft/yr); • Percolation from Applied Agricultural Irrigafion (1,000 acre-ft/yr); and Groundwater Inflow from the Bonsall Basin (400 acre-ft/yr). As an independent check of the previous groundwater inflow esfimate from Bonsall Basin, GEOSCIENCE conducted a groundwater underflow analysis for the alluvial aquifer at'the Bonsall Narrows. The underflow analysis ufilized average transmissivity, aquifer width, and GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 31 GeohydrologicTnvestigation - Lower San Luis Rey River Valley 31-Aug-04 hydraulic gradient to solve Darcy's Law through the use of a flow net. Transmissivity values for the underflow esfimates were obtained from pumping tests and lithologic data of wells within and/or immediately adjacent to the Bonsall Narrows. Hydraulic gradient was obtained from a groundwater level contour map (see Figure 8). Saturated cross-secfional area (width) was determined from driller's logs,, aerial photos and topographic maps of the area. Tfie subsurface inflow from the Bonsall Basin was calculated using the following equafion: Q = 892 where: Q = Subsurface Inflow [acre-ft/yr] A = Cross-Secfional Area of Flow [ft^] K = Average Hydraulic Conducfivity of Aquifer [gpd/ft ] dhldx = Hydraulic Gradient [ft/ft] The table below summarizes the saturated cross sectional area, hydraulic gradient, and the hydraulic conductivity for the secfion within the lower watershed. Groundwater Inflow Estimates From Bonsall Basin Cross Section Location Cross Sectional Area Of Flow Hydraulic Gradient Hydraulic Conductivity Groundwater Inflow (A) {dh/dx) (K) (Q) [ft'l [ft/ft] [gpd/ft'l [acre-ft/yr] ' Bonsall Narrows 28,000 0.0083 1,600 416 GEOSCIENCE Support Services, Inc. 32 Tetra Tech/San Diego County Water Authority Geohydrologic Investigadon - Lower San Luis Rey River Valley 31-Aug-04 The Bonsall Narrows section represents the inflow to the Mission Basin from the main alluvial channel of the San Luis Rey River. Based on the underflow analysis, the estimated groundwater inflow is 416 acre-ft/yr. It should be noted that this underflow calculafion at the Bonsall NaiTows only accounts for inflow to the alluvial aquifer from the San Luis Rey River and does not account for inflow from other sources. 5.2.5.2 Estimates of Groundwater Discharge Sources of groundwater discharge (outflow) from the Mission Basin include groundwater pumping from wells, evapotranspirafion, and underflow to the Pacific Ocean in the vicinity of the Mission Narrows. The City of Oceanside currently operates five vertical production wells with a combined average annual producfion of 2,867 acre-ft/yr (City of Oceanside, 2004). Annual losses from evapotranspiration along the San Luis Rey River are esfimated to be approximately 1,000 acre-ft/yr (NBS Lowry, 1993). A subsurface outflow estimate was made in the westem portion of the Mission Basin using the same method as described in Section 5.2.5.1. The saturated cross sectional area, hydraulic gradient, and the hydraulic conductivity for this area of the watershed are provided in the following table: Subsurface Outflow from Western Portion of Mission Basin Cross Sectional Hydraulic Hydraulic Groundwater Area . Gradient Conductivity Outflow Cross Section Location Of Flow (A) (Dh/Dx) (K) (Q) [ft'] [ft/ft] [gpd/ft'] [acre-ft/yr] Site 1 (Mission Narrows) 64,500 0.0018 763 99 GEOSCIENCE Support Services. Inc. 33 Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 The Mission Narrows section of the lower San Luis Rey River represents groundwater outflow- (discharge) from the Mission Groundwater Basin. Based on the underflow analysis at Site 1, the estimated groundwater discharge is approximately 99 acre-ft/yr. Thus, the total groundwater outflow from the Mission Basin, which includes 2,867 acre-ft/yr from pumping, 1,000 acre-ft/yr from evapotranspiration, and. 99 acre-ft/yr from subsurface outflow to the Pacific Ocean, is approximately 4,000 acre-ft/yr. 5.2.5.3 Net Change in Groundwater Budget Comparison of the average annual recharge range of 6,700 to 8,500 acre-ft/yr with the estimate of average annual discharge of 4,000 acre-fl/yr indicates a groundwater budget surplus of approximately 2,700 to 4,500 acre-ft/yr. Some of the surplus of groundwater that enters the Mission Basin on an average annual basis goes into aquifer storage. However, given the relafively shallow groundwater levels in the Mission Basin, it is likely that the majority of surplus groundwater discharges to the San Luis Rey River in the vicinity of the Mission Narrows and exits the basin as surface water flow. 5.2.6 Groundwater Quality The water quality of the groundwater in the alluvial aquifers of the Mission Basin has historically been characterized by relatively high concentrations of total dissolved solids (TDS), chloride and sulfate. TDS concentrations typically range between 1,000 and 1,500 mg/L (NBS Lowry, 1992). Chloride and sulfate concentrafions typically exceed the secondary maximum contaminant level (MCL) for these consfituents, which are both 250 mg/L (Izbicki, 1985a). The high concentrafions of these constituents are indicafive of seawater and may be a result of lateral and upward migrafion of saline water from the marine sedimentary formafions that surround the basin (Moreland, 1974) and seawater intmsion that has occurred as GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 34 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 a result of lowered groundwater levels in the basin due to pumping, which increased substanfially in the mid 1940s (DWR, 1958). Historically, the TDS concentration of groundwater from wells perforated within the La Jolla Group in the Mission Basin ranged from 1,140 to 2,390 mg/L (Izbicki, 1985a). Groundwater quality in these deep wells was typical of sodium chloride type water. Sulfate and chloride typically exceeded the MCLs for these constituents (Izbicki, 1985a). Groundwater in the Bonsall Basin also contains relafively high concentrations of TDS, chloride and sulfate. TDS concentrafions have been measured between approximately 700 and 2,300 mg/L (Izbicki, 1985b; GEOSCIENCE, 1993; L.R. Burzell, 1999). Chloride and sulfate concentrafions typically exceed MCLs for drinking water standards (Izbicki, 1985a). In addifion to seawater intrusion, agricultural land use practices have resulted in water quality impacts to the surface and groundwater in the Mission and Bonsall Basins. Fertilizer used on crops and orchards has resulted in irrigafion return flow with high concentrafions of nitrate and chloride. In addition, historical use of septic systems and wastewater discharge has also impacted the groundwater quality (Skrivan, 1976). With urbanizafion, water quality impacts from these sources are not as prevalent today as they were in the historical past (i.e. prior to 1965), although agricultural land use continues today in the Bonsall Basin. Currently there are 184 sites within the Oceanside area that are on file with the RWQCB as having underground storage tanks (USTs) that store petroleum-related products (RWQCB, 2004). Of these sites, 57 are either under investigafion for potenfial or known leaks or are undergoing active remediation. Locafions of these USTs, along with their status, are shown on Figure 9. Aside from regional water quality impacts (nitrate and TDS) and potenfial impacts from USTs, the primary groundwater contaminant impacting area production wells is 1,2,3-trichloropropane GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 35 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 (1,2,3-TCP). Concentrations of this compound in excess of 200 nanograms per liter (ng/L) have been detected in alluvial groundwater in Ihe vicinity of the Oceanside Desalter site. The current State of Califomia acfion level for 1,2,3-TCP is 5 ng/L. 5.2.7 Current Groundwater Use Current average annual groundwater production within the Mission Basin, which is almost completely from City of Oceanside wells, is approximately 2,800 acre-ft/yr. The balance of surface and groundwater that is not ufilized within the basin discharges to the Pacific Ocean through Mission Narrows at the west end ofthe basin. A field survey conducted by the SDCWA in 1995 identified seventy-eight groundwater wells within the Bonsall Basin. Farms, citms groves and golf courses are currently the primary users of groundwater within the Bonsall Basin. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 36 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 6.0 PROJECT SITES Several candidate recharge and extraction facility sites located within the Mission and Bonsall Basins were identified in Phase 2A of SDCWA's feasibility study. Following a comprehensive invesfigation of existing conditions and subsequent qualitafive ranking of geohydrologic attributes of perspective sites within the two basins, a total of fifteen sites were selected for the Phase 2 field investigation program. Of these candidate sites, subsurface invesfigations were conducted at fourteen (14) sites located within the Mission Basin and at one site located within the Bonsall Basin (see Figures 3 and 4).. This section provides a physical descripfion of each site and an inventory of exisfing wells, planned Phase 2 exploratory boreholes, monitoring wells, and test wells, and potenfial use of each site for conjunctive-use projects. Drilling and well construction methodology for the Phase 2 field investigation program are discussed further in Secfions 7.2 through 7.5. Borehole, monitoring well and test well construction details are summarized in Tables 2 and 3. 6.1 Mission Basin Sites 6.1.1 Site 1 Site 1 is located at the westernmost portion of the Mission Basin, approximately one mile inland from the Pacific Ocean (see Figure 3 and Appendix A-Site 1) and is a potenfial seawater intmsion barrier site. The site is owned by the City of Oceanside and consists of 5.12 acres of riparian land. The majority of Site 1 is situated within a narrow, steep-walled canyon (referred to in other reports as either San Luis Rey Canyon or the Mission Narrows) that flanks the San Luis Rey River. No wells or borings have been previously drilled on the property. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authonty 37 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Throughout the 1950's when heavy pumping lowered groundwater elevafions in the westem basin below sea level, evidence of seawater intmsion was observed in wells located immediately to the east of Site 1 (DWR, 1958). Site 1 was idenfified in Phase 2A as a potenfial injection barrier site that would prevent the inland intrusion of seawater in the event that extraction activifies associated with conjunctive use operation of the Mission Basin resulted in lowered groundwater levels. A total of four exploratory boreholes, two of which were converted'to groundwater monitoring wells, and one test well were drilled and installed from January to February 2002 during the Phase 2 field invesfigation (see Table 2). Boreholes (lA, IB, B-3 and B-4) were drilled into bedrock (San Onofre Breccia) in a row perpendicular to the river channel to evaluate the basin geometry, assess the shallow underlying strafigraphy, and to invesfigate the hydraulic properties of the sedimentary bedrock, Following completion, boreholes lA and IB were converted to groundwater monitoring wells lA/MWl and 1B/MW2, respectively (see Table 3). The monitoring wells are perforated wilhin the alluvium. One test well (IC/TWl) was constructed approximately 10 ft west of monitoring well 1B/MW2 and completed to a depth of 240 ft bgs. The test well is perforated within the alluvium to determine aquifer characterisfics. 6.1.2 Site2A Site 2A is located adjacent to the San Luis Rey River near Foussat Street on a 5.2-acre storm water retenfion basin owned by the City of Oceanside (see Figure 3 and Appendix A-Site 2A). No wells or borings are known to have been drilled on the property prior to the Phase 2 field invesfigafion. Although Site 2A is a potential artificial recharge and/or extracfion well site, it was also selected to provide a point of groundwater level information to monitor the groundwater gradient between the proposed injection barrier at Site 1 and the existing Mission Basin Desalting Facility. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 38 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 Two exploratory boreholes, one of which was converted to a nested monitoring well, were drilled at Site 2A during the Phase 2 field investigation (see Table 2). One exploratory borehole (2A/B1) was drilled to a depth of 118 ft bgs in 2002 and an addifional exploratory borehole (2A/B2) was drilled to a depth of 310 ft bgs in September 2003. Borehole 2A/B2 was converted to a nested monitoring well (2A/B2/MW1-S and 2A/B2/MW1-D). The "S" and "D" designafions signify the shallow and deep well casings, respectively. In the case of 2A/B2/MW1, the shallow casing is perforated enfirely within the alluvial aquifer and the deep casing is perforated entirely within the bedrock aquifer (see Table 3). 6.1.3 Site2B Site 2B is located on a vacant 21.76 acre parcel owned by the City of Oceanside within the San Luis Rey River drainage near the comer of Foussat Street and Shadowtree Drive (see Figure 3 and Appendix A-Site 2B). No wells or borings are known to have been drilled on the property prior to the Phase 2 field investigafion. One exploratory borehole (2B/B1) was drilled during Phase 2 work (see Table 2). The borehole was drilled a total depth of approximately 130 ft bgs, nine ft into sandstone bedrock. Continuous cores were collected from near the ground surface to the total borehole depth. Following borehole geophysics, 2B/B1 was converted to a monitoring well (2B/B1/MW1) in February 2002. The monitoring well consists of 2-inch diameter well casing that is perforated in the alluvial aquifer immediately above sandstone bedrock (see Table 3). The potential use of Site 2B for the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extraction. GEOSCIENCE Support Services, Inc. Tetra Tcch/San Diego County Water Authority 39 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 6.1.4 Site 3B Site 3B is located between the west end of Aspen Street (near its intersection with Los Arbolitos Blvd.) and the San Luis Rey River in an undeveloped, 7;38-acre parcel owned by the City of Oceanside (see Figure 3 and Appendix A- Site 3B). No wells or borings are known to have been previously drilled on the property. Two exploratory boreholes (see Table 2), one monitoring well, and one nested monitoring well were drilled and constmcted at Site 3B during the Phase 2 field invesfigafions. Exploratory borehole 3B/B1 was drilled to a depth of 107 ft bgs (approximately seven ft into bedrock) March 2002. Upon complefion, borehole 3B/B1 was converted to a groundwater monitoring well (3B/B1/MW1) to provide long-term groundwater level and groundwater quality data. The monitoring well consists of 2-inch diameter well casing that is perforated above the sandstone bedrock within a 30 foot zone of unconsolidated alluvium. Exploratory borehole 3B/B2 was drilled approximately 350 ft into bedrock to a depth of 450 ft bgs in September 2003. Upon completion of borehole 3B/B2, it was converted to a nested groundwater monitoring well (3B/B2/MW2-S and 3B/B2/MW2-D). In the case of 3B/B2/MW2, both casings were installed at different depths within the bedrock aquifer (see Table 3). The potential use of Site 3B for the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extracfion. 6.1.5 Site 3C Site 3C is located the San Luis Rey River and Cypress Street (see Figure 3 and Appendix A-Site 3C). No wells or borings are known to have been previously drilled on the property. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 40 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 One exploratory borehole (3C/B1) was completed to a depth of 264 ft bgs in early March 2002 during Phase 2 work. After obtaining a suite of borehole geophysical logs, the borehole was subsequently backfilled. Borehole details are discussed further in Secfion 7.2 and are summarized in Table 2. The potential use of Site 3C for.the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extraction. 6.1.6 Site 7A Site 7A is located adjacent to the San Luis Rey River near the comer of Frazee Road and Oleander Drive (see Figure 3 and Appendix A- Site 7A). The site is owned by the City of Oceanside and. consists of approximately 27 acres of undeveloped land. No wells or borings are known to have been drilled on the property prior to the Phase 2 field invesfigafion. An exploratory borehole and one monitoring well were constmcted during Phase 2 work. Borehole 7A/B1 was drilled to a depth of approximately 170 ft bgs, approximately 20 ft into bedrock, in March 2002 (see Table 2). The borehole was converted to a monitoring well (7A/B1/MW1) in March 2002 to provide long-term water level and water quality data for the feasibility study. The monitoring well consists of 2-inch diameter well casing that is perforated at the base of the alluvium (see Table 3). The potential use of Site 7A for the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extraction. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 41 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 6.1.7 Site9A Site 9A consists of 25 acres owned by the City of Oceanside located adjacent to the San Luis Rey River in the vicinity of Old Grove Drive and Frazee Street (see Figure 3 and Appendix A-Site 9A). Two exisfing observafion wells (OW-8 and OW-9) were installed prior to Phase 2 field invesfigafions at the property for SDCWA in 2001. In addition, two wells identified from the United States Geological Survey well database were located (status unknown) on the north side of the property boundary. One exploratory borehole (9A/B1) was completed during Phase 2 work in March 2002 (see Table 2). The borehole was drilled to a total depth of 124 ft bgs. Soil samples were collected from 9A/B1 to assess the potential to use the site as an artificial recharge and/or extraction well site. The borehole was advanced approximately 9 ft into sandstone bedrock to confirm depth to bedrock in this porfion ofthe Mission Basin. Although Site 9A was selected as a candidate extraction and artificial recharge site, the site also was selected to confirm depth to bedrock and to provide long-term water level data to assist in groundwater flow monitoring. 6.1.8 Site lOA Site lOA is an exisfing storm water detenfion basin located on the southwest comer of Mission Avenue and Rancho Del Oro Drive (see Figure 3 and Appendix A-Site lOA). No wells or borings are known to have been drilled prior to the Phase 2 field investigation. One exploratory borehole (lOA/Bl), which was converted to a monitoring well (lOA/Bl/MWl) was constmcted at this site during Phase 2 work. Borehole lOA/Bl was drilled to a depth of 190 ft bgs below the top of the levee on the north side of the site just south of Mission Ave and west of Rancho Del Oro (see Table 2). Semi-consolidated sandstone bedrock (La Jolla GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 42 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Formafion) was encountered within lOA/Bl below an approximate depth of 153 ft bgs. The borehole was converted to a monitoring well (lOA/Bl/MWl) in March 2002 to provide long-term water level and water quality data for the, feasibility study. The monitoring well consists of 2-inch diameter well casing that is perforated in the alluvial aquifer immediately above sandstone bedrock (see Table 3). The purpose ofthe field investigation at Site lOA was to evaluate the site's potenfial for artificial recharge and/or extracfion. Specifically, the site may be a candidate for surface recharge and, as such, the focus of the invesfigation was on the unconsolidated alluvial sediments of the Mission Basin. 6.1.9 Site 11 Site 11 is located in a vacant field approximately 4,000 ft due north of the San Luis Rey River near Douglas Drive in the vicinity of the Oceanside Municipal Golf Course (see Figure 3 and Appendix A- Site 11). No wells or borings are known to have been drilled prior to the Phase 2 field investigation. The focus of the field investigafion at Site 11 was to assess the underlying stratigraphy and to verify depth to bedrock. One exploratory borehole (11/Bl) was completed during Phase 2 in January 2002 to a depth-of approximately 150 ft bgs (see Table 2). Undisturbed cores of unconsolidated alluvium and sandstone bedrock were collected from 11/Bl. A monitoring well was not installed within the borehole and 11/Bl was subsequenfiy backfilled. The potential use of Site 11 for the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extracfion. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 43 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 6.1.10 Site lie Site 1 IC is a vacant 14.93-acre lot owned by the City of Oceanside located north of the San Luis Rey River and southwest of Whelan Lake near the southern boundary of Camp Pendleton (see Figure 3 and Appendix A- Site 1 IC). One exploratory borehole (llC/Bl) was drilled during Phase 2 work in September 2003 (see Table 2). The borehole was drilled a total depth of approximately 500 ft bgs. The purpose of 1 IC/Bl was to assess the depth and character of alluvial and bedrock sediments beneath the site. In order to determine water quality of the bedrock aquifer, and to provide long-term water level data, borehole llC/Bl was converted to a nested monitoring well (1 IC/Bl/MWl-S and llC/Bl/MWl-D) consisting of two well casings. The "S" and "D" designafions signify the shallow and deep well casings, respectively. In the case of 1 IC/Bl/MWl, both casings (shallow and deep) were perforated at varying depths within the bedrock aquifer (see Table 3). The purpose of the dual-completion was to determine whether the water-bearing units within the bedrock are hydraulically connected. The potential use of Site 1 IC for the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extraction. 6.1.11 Site 13 Site 13 is a vacant area owned by the City of Oceanside and is located in the vicinity of the San Luis Rey River near College Drive (see Figure 3 and Appendix A-Site 13). No wells or borings are known to have been drilled on the property prior lo the Phase 2 field investigafion. One exploratory borehole (13/Bl) was completed during Phase 2 work in Febmary 2002 (see Table 2). The borehole was drilled to a total depth of approximately 166 ft bgs. Undisturbed cores of unconsolidated alluvium and granific bedrock (tonalite) were collected GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 44 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 from 13/Bl. A monitoring well was not installed within the borehole and 13/Bl was subsequenfiy backfilled. The focus of the field invesfigafion at Site 13 was to assess the underlying stratigraphy and to determine whether this site was suitable for the installation of project extraction well(s). 6.1.12 Site 13A Site 13A is a vacant area located in the vicinity of Site 13 and the San Luis Rey River near College Drive (see Figure 3 and Appendix A- Site 13A). No wells or borings are known to have been drilled on the property prior to the Phase 2 field invesfigafion. The focus of the field investigation at Site 13A was to assess the underlying stratigraphy of the alluvium adjacent to the river channel and to provide long-term groundwater level data. One exploratory borehole (13A/B1) was drilled to a depth of 135 ft bgs (see Table 2) and subsequenfiy converted to a groundwater monitoring well (13A/B1/MW1) in Febmary 2002. The monitoring well consists of 2-inch diameter well casing that is perforated within the upper portion of the alluvium (see Table 3). The potenfial use of Site 13A for the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extracfion. 6.L13 Site 32 Site 32 is a vacant 2.75-acre parcel owned by the City of Carisbad, located near the comer of Foussat Street and Mission Avenue (see Figure 3 and Appendix A- Site 32). In the past, Site 32 made up the westem portion of a groundwater production well field owned and operated by the City of Carlsbad. Although a total of four abandoned production wells were idenfified at this GEOSCIENCE Support Services, Inc. Telra Tcch/San Diego County Water Authority 45 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 site from the United States Geological Survey well database, these wells are believed to have been destroyed in December 2003. Site 32 was selected to provide a point of water level information to monitor the groundwater gradient between the proposed injection barrier at Site 1 and the exisfing Mission Basin Desalting Facility. One exploratory borehole, which was subsequently converted to a groundwater monitoring well, was drilled during Phase 2 work. Exploratory borehole 32/Bl was drilled in early March 2002 to assess the underlying stratigraphy and to verify depth to bedrock in this porfion of the Mission Basin (see Table 2). Upon completion of the borehole, 32/Bl was converted to a monitoring well 32/Bl/MWl to provide long-term water level and water quality data for the feasibility study. The monitoring well consists of 2-inch diameter well casing that is perforated in the alluvial aquifer immediately above sandstone bedrock (see Table 3). The potenfial use of Site 32 for the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extraction. 6.1.14 Desalter Site The Oceanside Desalter is located at 215 Fireside Street in the City of Oceanside (see Figure 3 and Appendix A- Desalter Site). Four exisfing monitoring wells are located on the site as well as three production wells (Nos. 1, 2 and 3) operated by the City of Oceanside to supply the desalter plant. During Phase 2 field invesfigations, two exploratory boreholes were drilled and tested (see Table 2), Exploratory boreholes (D/Bl and D/B2) were drilled in August and September 2003, respectively. The purpose of the exploratory boreholes was to evaluate the character of the alluvium, lateral extent and character of confining layers previously described in the area, determine the depth and character of bedrock, and assess water quality differences between the alluvial aquifer and the bedrock aquifer. Upon borehole completion, it was GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Waler Authority 46 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 determined that borehole D/Bl be abandoned, while borehole D/B2 was converted to a nested groundwater monitoring well (D/B2/MW1). In order to provide long-term groundwater level and groundwater quality data for the alluvial aquifer and bedrock aquifer in this portion of the Mission Basin, D/B2/MW1 was completed with two well casings (D/B2/MW1 -S and D/B2/MW1-D). The "S" and "D" designafions signify the shallow and deep well casings, respectively. In the case^of D/B2/MW1, the shallow casing was installed within the alluvial aquifer and the deep casing was installed within the bedrock aquifer (see Table 3). One test well (D/TW1/PW9) was also drilled during the Phase 2 field investigafion. Drilling of the test well was started on 7-Jan-04. Design of D/TW1/PW9 was based on the borehole log and sieve analysis of cutfings from the pilot borehole and from the confinuous core log of D/B2, located 50 ft to the north of D/TW1/PW9 (see Appendix A-Desalter Site). The potenfial use of the Desalter Site for the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extraction. 6.2 Bonsall Basin Site Site 26/27 is located southwest of the intersection of Pala Road (SR 76) and Old Highway 395, west of Interstate 15 within the equipment yard of the Rainbow Municipal Water District (see Figure 4 and Appendix A-Site 26/27). No wells or borings have been previously drilled on the property, although two wells idenfified from the United States Geological Survey well database were located (status unknown) to the west of the site. One exploratory soil borehole was drilled and subsequently converted to a nested monitoring well at Site 26/27. Exploratory borehole 26/27/Bl was drilled to a total depth of 132 ft bgs (approximately 16 ft into bedrock; see Table 2). Upon completion, borehole 26/27/Bl was converted to a nested groundwater monitoring well (26/27/Bl/MWl-S and 26/27/Bl/MWl-D) in GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 47 Geohydrologic Investigation - Lowcr San Luis Rey River Valley 31 -Aug-04 October 2003 with both casings (shallow and deep) installed at different depths within the alluvial aquifer (see Table 3). The potenfial use of Site 26/27 for the Groundwater Storage and Recovery Project would be for either groundwater recharge and/or extraction. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 48 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 7.0 FIELD INVESTIGATION PROGRAM METHODOLOGY The drilling and testing program of the Phase 2 field investigafion was implemented to assess the feasibility of artificial recharge and enable the development of a groundwater storage and recovery strategy for the Mission and Bonsall Basins. Prior to the drilling and testing program, the following geohydrologic data gaps associated with the basins had been idenfified: Aquifer and near surface soil characteristics. Mineralogy of aquifer materials,. Groundwater levels and flow characterisfics. Alluvial and bedrock aquifer groundwater quality. Alluvial and bedrock aquifer characterisfics, and Alluvial and bedrock aquifer storage potenfial. To address the data gaps, a comprehensive field drilling program was developed that included: 1 surface resisfivity survey, 23 exploratory boreholes, 8 single-complefion monitoring wells, 5 nested monitoring wells, 2 test wells, and 3 aquifer pumping tests. This section describes the methodology used in the collecfion of geohydrologic data from the boreholes and wells summarized above. A summary of the boreholes drilled and wells GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 49 Geohydrologic Investigation - Lower San Luis Rey Rivcr Valley 31-Aug-04 constructed during the Phase 2 field investigafion can be found in Tables 2 and 3. The locations of the boreholes and wells are shown on site-specific figures provided in Appendix A. Findings from the field investigation program are provided in Secfions 8 and 9. 7.1 Surface Resistivity Survey A surface resistivity survey was conducted by Southem Califomia Soil and Tesfing (SCS&T) to evaluate the subsurface basin geometry at multiple sites within the Project Area (SCS&T, 2003). Field data using the AGI STING System was collected from Febmary to March 2003 at four field invesfigafion sites (Sites 1, 9A, lOA, and 11), and at a locafion approximately 2,000 ft south of the San Luis Rey River, east of Douglas Drive. 7.2 Exploratory Boreholes Twenty-two exploratory boreholes were drilled at fifteen sites located within the Mission Basin (see Figure 3; Table 2). An additional exploratory borehole was drilled at a site located within the Bonsall Basin (see Figure 4; Table 2). Phase 2 exploratory boreholes were drilled by Water Development Corporafion (WDC) of Montclair, Califomia between 16~Jan-03 and 24-Mar-03 and between 12-Aug-03 and 6-Oct-03. All boreholes were drilled using a mud rotary drilling rig equipped with a Christensen 94 mm Wireline coring system (see Figure 10). Boreholes were drilled to depths ranging from 90 ft bgs to 501 ft bgs as summarized in Table 2. Selected boreholes were completed as monitoring wells as described in Section 7.3. Soil and bedrock samples were collected from each exploratory borehole to characterize subsurface stratigraphy and mineralogy, to identify hydrostratigraphic units, and to help define the geometry of those units. Undisturbed soil samples were collected from various depth intervals in all twenty-three exploratory boreholes using a Christensen 94 mm wireline core barrel sampler. Core samples were placed in waxed-lined core boxes for storage (see Figure 11). GEOSCIENCE Support Services, Inc. ' Tetni Tech/San Diego County Water Authority 50 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Where continuous coring was not conducted, "grab" soil samples were collected at 5-foot intervals and placed in 1-gallon scalable plasfic bags. Each bag was properly labeled in the field with the boring number, sample depth, and date of collecfion. All core and grab samples were classified in the field using the Unified Soil Classificafion System (USCS). Lithologic logs for the exploratory boreholes are provided in Appendix B. A detailed description of the findings from the data obtained from the test boreholes is provided in Secfions 8 (Mission Basin) and 9 (Bonsall Basin). 7,2.1 Soil Sampling Selected undisturbed soil core samples were submitted to Southem Califomia Soil & Tesfing, Inc., of San Diego, Califomia for analysis of the following: Consolidation (ASTM D2435), Hydraulic Conducfivity (ASTM D5084), Total porosity (API RP40), and Effective Porosity (API RP 40). Consolidation tests were performed on undisturbed samples of silt and clay obtained from exploratory boreholes 2A/B2, llC/Bl, and D/B2 from depths of approximately 95 ft bgs, 92 ft bgs, and 75 ft bgs, respectively. The results from consolidation testing were used to evaluate the potential for land subsidence within the Mission Basin, which is discussed in Secfion 10.2.2. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Waler Authority 51 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Saturated hydraulic conducfivity, total porosity, and effecfive porosity tests were performed on undisturbed sandstone bedrock samples obtained from exploratory boreholes 2A/B2 (145 and 241 ft bgs), 3B/B2 (175 and 252 ft bgs), 1 IC/Bl (78 ft bgs), and D/B2 (206 and 401 ft bgs). The results from hydraulic conductivity and porosity tesfing were used to evaluate the ability of the sedimentary bedrock to transmit groundwater, which is discussed in Section 8.2.3.3. Laboratory results of soil physical properties are listed in Table 4. Details of the test procedures for consolidauon and hydraulic conductivity and a copy of the laboratory report are provided as Appendix C. 7.2.2 Depth-Specific Groundwater Sampling During the drilling of borehole D/Bl, a groundwater sample was collected from a depth of approximately 93 ft bgs using a SimulProbe sampling apparatus. The sample was submitted to Del Mar Analytical, a Slate-Certified analytical laboratory, under chain-of-custody protocol. The sample was collected in order to assess the water chemistry at or near the alluvium/bedrock interface. A summary of the constituents tested and their detecfion limits are provided in Table 5. A copy ofthe laboratory groundwater analytical report is provided in Appendix D. 7.2.3 Geophysical Borehole Logging At the completion of borehole drilling, geophysical borehole logs were obtained from eight exploratory boreholes at seven sites during the Phase 2 field invesfigafions by Pacific Surveys of Claremoiit, Califomia. • 16-inch and 64-inch resisfivity with point resistance; Spontaneous potential (SP); GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 52 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Laterolog 3; Guard Resisfivity; Gamma Ray; Acousfic (sonic); Variable Density; and Porosity. A summary of boreholes with type of logs performed, borehole diameters, total borehole depths and logged intervals are shown in Table 6. Geophysical borehole logs were used in conjunction with the logged borehole lithology to design several of the monitoring wells, in addifion to the Desalter Test Well. Specifically, the geophysical logs were used to idenfify potential confining layers and the locafion of permeable aquifer units. Copies of the geophysical borehole logs are provided in Appendix E. 7.3 Groundwater Monitoring Wells A total of eight single-completion groundwater monitoring wells were installed at seven sites (Sites 1, 2B, 3B, 7A, lOA, 13A and 32) and four nested^ monitoring wells were installed at four sites (Sites 2A, 3B, IIC and Desalter) in the Mission Basin (see Figure 3). In addition, one nested monitoring well was installed at Site 26/27 located in the Bonsall Basin (see Figure 4). 3 Nested monitoring wells consist of two 2-inch diameter casings installed wilhin the same borehole. Each casing is completed with a different perforated interval. The perforated intervals are separated within the borehole by a bentonite seal (see Figure 13 and Appendix F). GEOSCIENCE Support Service.>!, Inc. Tetra Tech/San Diego Couniy Waler Authority 53 Geohydrologic Investigation - Lower San Luis Rey River Valley . 31-Aug-04 Ail single-completion monitoring wells (lA/MWl, 1B/MW2, 2B/B1/MW1, 3B/B1/MW], 7A/B1/MW1, lOA/Bl/MWl, 13A/B1/MW1 and 32/Bl/MWl; see Table 3) were completed in the alluvium of the Mission Basin. Two nested monitoring wells (2A/B2/MW1 and D/B2/MW1) were completed with well casings perforated within both the alluvial and bedrock aquifers of the Mission Basin. Two nested monitoring wells (3B/B2/MW2 and llC/Bl/MWI) were completed with both well casings perforated within the sandstone bedrock underlying the Mission Basin. One nested monitoring well (26/27/MWl) had both well casings completed within the underlying alluvium of the Bonsall Basin. The eight single-complefion monitoring wells constmcted in the Mission Basin were drilled and installed during Phase 2 field investigations from January to March 2002. All five nested monitoring wells were drilled and installed during Phase 2 field investigations from September to October 2003. 7.3.1 Construction and Completion Details Monitoring wells 1A/MW1, 1B/MW2, 2B/B1 /M W1, 3B/B1 /MW 1, 7 A/B1 /MW 1, lOA/Bl/MWl, 13A/B1/MW1, and 32/Bl/MWl were constmcted within the 3 1/8-inch diameter borehole generated during coring. With the exception of 1B/MW2, all of these wells were constructed with 2-inch diameter schedule 40 PVC casing and screen. The borehole for monitoring well 1B/MW2 was enlarged (reamed) to 16-inch diameter and completed as a 4-inch diameter monitoring well. The perforated portion of each well casing consisted of 0.01-inch horizontal slots, with the excepfion of wells at Site 1, which were constructed with slot sizes of 0.02-inch (lA/MWl) and 0.08-inch (1B/MW2). The annular space between the borehole wail and the screened porfions of each monitoring well were filled with three different types of filter pack material. Specifically, monitoring wells lA/MWl, 2B/B1/MW1, 3B/B1/MW1, 7A/B1/MW1, and lOA/Bl/MWl were filled with RMC # 2/16 filter pack, monitoring wells 13/^Bl/MWl and 32/Bl/MWl were filled with #3 sand filter pack, and monitoring well 1B/MW2 was filled with RMC 4 x 12 sand filter pack. With the exception of 1B/MW2 and 13A/B1/MW1, annular seals consisting of bentonite chips were placed on top of the filter pack GEOSCIENCE Support Services, Inc, Tetra Tech/San Diego County Water Authority 54 Geohydrologic Investigation - Lowcr San Luis Rey River Valley 31 -Aug-04 material up to approximately 2 ft bgs in each monitoring well. The annual space above the filter pack material to the ground surface in 1B/MW2 was filled with grout, and with concrete in 13A/B1/MW1. Monitoring well complefion details are summarized in Table 3. Well completion diagrams (as-builts) for all single-complefion monitoring wells are provided in Appendix F. Nested monitoring wells 2A/B2/MW1, 3B/B2/MW2, D/B2/MW1, llC/Bl/MWl, and 26/27/Bl/MWl were constructed within the 10.5-inch diameter borehole generated by reaming the initial 5-inch diameter pilot borehole. Monitoring wells 2A/B2/MW1-S, D/B2/MW1-S, 26/27/Bl/MWl-S, and 26/27/Bl/MWl-D were constructed with 2-inch diameter schedule 40 PVC well casing and screen (see Figures 12 and 13; Appendix F). Monitoring wells 2A/B2/MW1-D, D/B2/MW1-D, 3B/B2/MW2-S and -D, and llC/Bl/MWl-S and -D were constmcted with 2-inch diameter schedule 80 PVC well casing and screen (see Appendix F). The perforated portion of each well casing consisted of 0.02-inch horizontal slots. The annular space between the borehole wall and the well casing was filled with #3 artificial filter pack from the bottom of the borehole to below the annual seal for each nested well. To ensure that the water-bearing zone for each perforated casing interval was hydraulically isolated from one another, an annular seal, with a minimum thickness of 5-ft, was placed between the top of the lower filter pack zone and the bottom of the upper filter pack zone. A cement-bentonite slurry seal was installed for each nested monitoring well within the annular space from the ground surface to approximately 20 ft bgs. Nested monitoring well completion details are summarized in Table 3. Well completion diagrams (as-built) for all nested monitoring wells are provided in Appendix F. Monitoring wells 2B/B1/MW1, 7A/B1/MW1, and lOA/Bl/MWl were completed with concrete well pads and flush-mounted, traffic-rated well boxes with lockable well covers. All other monitoring wells were completed at the ground surface with concrete well pads and steel monuments with lockable covers as shown in Figure 14 and illustrated in Appendix F. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 55 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 7.3.2 Development After installafion, all nested monitoring wells were developed using a combination of airlifting and swabbing. Drilling fluids and development water was discharged to the ground surface and contained near each respective monitoring well. This method was continued for each well until the groundwater produced from airlifting was relafively free of suspended sediment. 7,3.3 Groundwater Sample Collection As part of the drilling and testing program of the Phase 2 field investigafion, groundwater samples were collected from nested monitoring wells 2A/B2, 3B/B2, llC/Bl, D/B2, and 26/27/B1 at the end of development. The samples were collected by transferring water from the discharge line into laboratory-prepared sample containers. Each container was labeled and immediately stored on ice in a portable cooler. All samples were submitted to Del Mar Anaiydcal, a State-Certified analytical laboratory, under chain-of-custody protocol. Testing results were used to assess the groundwater quality of the alluvial and bedrock aquifers in the Mission and Bonsall Basins, which is discussed in Secfion 8.3. A summary of the constituents tested and their detection limits are provided in Table 5. Laboratory groundwater analyfical reports are provided in Appendix D. 7.4 Site 1 Test Well (IC/TWl) Drilling of the Site 1 test well (IC/TWl) took place from 21-Jan to 24-Jan-02. Design of the test well was based on the borehole geophysical log and mechanical grading analysis of cuttings that represented the range of potential aquifer materials to be screened. The purpose of IC/TWl was to enable a pumping test at Site 1 to evaluate aquifer properties that would provide a basis for evaluating the feasibility of construcfing a seawater intrusion barrier at this site. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 56 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 7.4.1 Construction and Completion Details The pilot borehole for IC/TWl was drilled using a direct mud rotary drilling rig equipped with a 4 '/2-inch-diameter bit. The cuttings were classified in the field using the USCS system by a Tetra Tech geologist. The pilot borehole was enlarged (reamed) to a final diameter of 16 inches to a depth of 240 ft bgs. Bedrock material of the San Onofre breccia was encountered approximately 216 ft bgs. Test Well IC/TWl was installed on 4-Feb-02 to a tolal depth of 230 ft bgs and consists of 6-inch diameter type 304 stainless steel casing with 140 ft (80 to 220 ft bgs) of 0.080-inch extra strength wire wrapped well screen (see Appendix G). Blank casing consisting of 6-inch diameter schedule 80 PVC was installed from ground surface to 80 ft bgs, and from 220 ft to 230 ft bgs. The borehole for IC/TWl was backfilled from the tolal depth (240 ft bgs) lo 74 ft bgs with RMC 4 X 12 filter pack material as selected based on sieve analyses from samples collected in the IC/TWl borehole. The remaining annulus from approximately ground surface lo 74 ft bgs was then backfilled with a cement grout. The top of the well was completed with a 12-inch diameter, lockable monument cover that extends approximately 3 fl above the ground surface. A 6-inch thick, 3-foot by 3-foot concrete apron was installed around the monument. 7.4.2 Pumping Test After development, a constant rate pumping test was performed to assess aquifer transmissivity and storativity in the Site 1 area. During the test, pumping groundwater levels and discharge rate of the test well were monitored and recorded. Groundwater levels in well lA/MWl, located approximately 23.5 ft to the west of IC/TWl, were measured during the constant rate test to monitor drawdown interference. The well was pumped at a constant rate of approximately GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 57 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 50 gpm for a period of approximately 5 hours and 38 minutes'^. Pumping test results are presented in Appendix H. Results of the constant rate pumping test are plotted on Figure 15. 7.5 Desalter Site - Well D/TW1/PW9 The Desalter Test Well D/TW1/PW9 was drilled, constmcted and tested between 7-Jan-04 and 27-Feb-04 by WDC using a fluid reverse circulation rotary drilling rig (see Appendix A-Desalter Site for locafion). GEOSCIENCE provided drilling and constmction inspecfion, well design, and testing support. The chronology of constmction for D/TW1/PW9 is summarized in Appendix 1. 7.5.1 Conductor Casing Installation Drilling of D/TW1/PW9 was inifiated with the installafion of a 50-ft deep conductor casing. The conductor casing was installed inside a 42-inch diameter borehole lhal was drilled to a depth of 50 ft bgs using a bucket auger rig (see Figure 16). A 30-inch OD by 5/16-inch wall mild steel conductor casing was installed on lO-Dec-03 to 50 ft bgs and cemented in place from ground surface to a depth of 50 ft bgs. Cementing of the conductor casing was inspected by a County of San Diego inspector who approved of the cement seal and conductor completion. 7.5.2 Pilot Borehole Drilling Following complefion of the conductor casing, a 17 '/z-inch diameter pilot borehole was drilled from the bottom of the conductor casing to a total depth of approximately 300 ft bgs using a fluid reverse circulation rotary drilling rig. Pilot borehole drilling began on 7-Jan-04 and was The Site 1 test well could not be pumped longer due lo excessive drawdown in the pumping well. GEOSCIENCE Support Services, Inc. Tetra Tcch/San Diego Couniy Water Authority 58 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 completed by 9-Jan-04. Grab samples were collected during drilling at 10-foot intervals and placed in 1-gallon scalable plastic bags. Soil samples were logged in the field by a GEOSCIENCE geologist as described in Section 7.2.1. A detailed lithologic log of the pilot borehole is provided in Appendix B. 7.5.3 Geophysical Borehole Logging Upon reaching the final depth of the pilot borehole (approximately 300 ft bgs), a suite of geophysical borehole logs were run by Pacific Surveys, Inc., of Claremont, California, which included the following: 16-inch and 64-inch resisfivity with point resistance; Spontaneous potential (SP); Laterolog 3; Guard Resistivity Gamma Ray; and Acousfic (sonic). The geophysical borehole logs were used in conjunction with the lithologic samples collected from the pilot borehole to identify aquifer zones with potenfially high permeability. The geophysical borehole logs are provided in Appendix E. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Waler Authorily 59 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 7.5.4 Aquifer Zone Testing for Yield and Water Quality Isolated aquifer zone testing was conducted in the D/TW1/PW9 pilot borehole to assess potenfial yield and waler quality at depth-specific intervals before determining the final design of the test well. From examination of the borehole log and analysis of the geophysical logs, three (3) intervals (245 to 265 ft, 190 to 210 ft, and UO to 130 ft bgs) were selected for isolated zone testing. Prior to zone testing, the open 17 V2-inch pilot borehole was backfilled with gravel to within approximately 10 ft of the bottom of the zone lest interval and bentonite lo within 5 ft of the bottom of the zone to be tested. A 20 ft section of perforated pipe (mill-slotted) was attached to an 8-inch diameter drill siring and inserted in the pilot borehole within the larget zone to be tested. Filter pack material was then added to the annular space between the 17 '/2-inch borehole and the zone test toot (perforated pipe), unfil the tool was covered by at least 10 ft of material. A second bentonite seal was placed on top of the filler pack to isolate the zone from the rest of the borehole. The bentonite seals were allowed to hydrate a specified arnount of time before airlifting of the isolated zone began. Each test zone was developed by airlifting the temporary "well" until the fluid being discharged remained acceptably clean and clear, and the integrity of the seal had been verified.^ If the seal was nol holding, more bentonite and/or cutfings were added to the annulus and were allowed to hydrate before continuing development. At the end of airlift development, a submersible pump was installed and pumped for several hours until the discharge water was considered representafive of formation water. The zone was then pumped continuously for an additional 6 hours. This additional pumping was to ensure that Verification of the seal for zone testing is determined when water levels occurring in the annulus remain stable and predictable (allowing for losses to the formation above the top seal), and is different than the water level measured inside the zone testing tools (i.e. the drill pipe), whether the zone is being actively pumped, or is at rest. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 60 Geohydrologic investigation - Lower San Luis Rey River Valley 31 -Aug-04 only formation water from the isolated zone was being produced, and that the water was unconlaminated by the fluids used during drilling. During this fime, periodic measurements were made of field water quality parameters, water levels and rales of discharge. Waler samples were collected at the end of the 6 hours and delivered to Del Mar Analyfical for water quality analyses. This process was repeated for each of the remaining two zones tested. 1. The zone test procedure is summarized below: 2. The 17 '/2-inch pilot borehole was backfilled to approximately 5 ft below the zone to be tested. A bentonite seal was placed on top ofthe backfill material. 3. A 20-foot long mill-slotted secfion of pipe was placed opposite the zone to be tested. 4. Filter pack material was placed in the annular space between the perforated tool and the borehole, to approximately 10 fl above the top of the tool. 5. Ten ft of bentonite material was placed on lop of the filter pack material to complete the zone isolafion process, and was allowed to hydrate. 6. The temporary well was developed by airlifting, and the integrity of the seal was verified. 7. Following airlift development, a submersible pump was installed and the tested zone was developed further through pumping. A summary of the groundwater level, pumping rate and field geochemical parameter data (pH, temperature, TDS and turbidity) collected during zone tesfing of the D/TW1/PW9 pilot borehole is provided in Table 7. Groundwater samples were collected from each zone and submitted to Del Mar Analyfical of Irvine, Califomia for analysis. The samples were collected by transferring water from the discharge line into laboratory-prepared sample containers. A summary of the GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority "61 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 - Aug-04 consfituents tested and their detecfion limits are shown in Table 5. Laboratory groundwater analytical reports are provided in Appendix D. 7.5.5 Filter Pack, Casing and Screen Design The filter pack, casing and screen design for D/TW1/PW9 was based on review of the core from D/B2/MW1 (located approximately 50 ft to the north of the test well), examinafion of the lithologic log generated from the pilot borehole, review of the geophysical logs, review of the mechanical grading analysis data, and review of the yield and waler quality data from zone tesfing, Samples selected for mechanical grading analyses included a representative range of potential aquifer materials, including those samples with primarily fine-grained sand or sand-silt mixtures. A composite plot of grain size distribufion for the seven formafion samples analyzed is shown on Figure 17. The mean grain diameter (i.e. the 50% passing size) of the aquifer materials ranged from 0.9 mm to 1.9 mm. Uniformity coefficients^ ranged from 3.1 to 8.7. Based on these data, the filter pack selected was a custom blend '/4-inch x 16. The grain size distribution of the selected filter pack is shown on Figure 17 with the formation samples. Summaries of mechanical grading analyses for each sample analyzed are provided in Appendix J. The D/TW1/PW9 well casing consisted of 16-inch ID by 5/16-inch wall type 304L stainless steel blank casing (manufactured by Roscoe Moss Company) from ground surface to 100 fl bgs and 220 to 240 ft bgs (see Figure 18). The well screen consisted of 16-inch ID by 5/16-inch wall type 304L stainless steel Ful-Flo horizontal louvered screen with 0.094-inch openings from 100 to 220 ft bgs. An end. plate made of the same material as the casing and screen was welded to the lowermost blank secfion. The well casing and screen was installed inside a 26-inch The uniformity coefficient is defined as the 60% passing grain size (deu) divided by the 10% passing grain size (d|[j). The lower the value of the uniformity coefficient the more uniform the grading, and the larger the value the less uniform the grading of the material. GEOSCIENCE Support Services, inc. Tetra Tech/San Diego Couniy Water Authority 62 Geohydrologic Investigation - Lowcr San Luis Rey River Valley 31-Aug-04 diameter borehole (total depth of 260 ft bgs) that had been enlarged from the original 17 '/2-inch diameter pilot borehole (see Figure 19). Prior to installafion of the well casing and filter pack, a caliper log was mn in the 26-inch diameter reamed borehole by Pacific Surveys, Inc. to assess the amount of filter pack required. A copy of the caliper log is included with the geophysical Jogs in Appendix E. Prior to installing the filter pack material, the borehole annulus was backfilled from the bottom of the borehole to 230 ft bgs with a 5/16 x 1/8 gravel. The custom blend '/4-inch x 16 filler pack material was installed within the annular space between the 26-inch diameter borehole and the 16-inch ID casing and screen from a depth of 230 ft bgs to 50 ft bgs. The filter pack material was pumped through a tremie pipe, starring from the bottom interval, using clear water as a circulating medium. The final well completion included a 2-inch diameter type 304L stainless steel sounding tube, welded to the outside of the well casing to a depth of 97 ft bgs. A 3-inch diameter schedule 40 (ASTM A53) Grade B steel gravel feed pipe was installed within the annular space between the 26-inch diameter borehole wall and the 16-inch diameter well casing to a depth of 57 ft bgs. A technical cross secfion of D/TW1/PW9, as il was constmcted, is provided in Appendix K. Well constmcfion details and materials are summarized in Table 8. 7.5.6 Well Development Test well D/TW1/PW9 was inifially developed using a combinafion airlifting and swabbing tool to consolidate the filter pack after placement, and to remove colloidal and fine-grained sediments form within the well, filter pack, and near-well zone. Ten-fool intervals were swabbed and GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 63 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 - Aug-04 airlifted simultaneously until relafively clean water was discharged. A total of approximately 43 hours were ultimately spent airlifting and swabbing the well. Final development was conducted between 10-Feb lo 13-Feb-04 using a vertical turbine test pump set at 89 ft bgs. Final development consisted of pumping the well at progressively increasing discharge rates while monitoring the sand content of the discharge waler. Pumping was begun at a low discharge rate (approximately 60 gpm) and increased when the sand concentration remained less than 5 parts per million (ppm). The 5 ppm threshold was maintained throughout the final day of development at discharge rates of up to approximately 2,100 gpm. A record of notes from the well development process is provided in Appendix L. The discharge rate was measured using an in-line propeller meter. Water level measurements were collected using an electronic sounder. During pumping, the sand concentrafion was measured using a centrifugal Rossum Sand Tester. When the specific capacity (discharge rate divided by drawdown) approached a maximum and the turbidity and sand concentration approached a minimum, well development was considered complete. During the final day of development by pumping, a maximum discharge rate of 2,100 gpm was achieved. Short-term specific capacifies on the final day ranged from 50 to 58 gpm per foot of drawdown. A total of approximately 32.5 hours were spent on development pumping. 7.5.7 Plumbness and Alignment Survey A plumbness and alignment (i.e. deviafion) survey was conducted on 24-Feb-04 by Pacific Surveys, Inc. to measure the verticality of the well. Results of the survey indicaled a deviation at 120 bgs of 3.6 inches in the North-South plane and 0.0 inches in the East-West plane (see Figure 20). The maximum deviation in the North-South plane was 9.6 inches, occurring al a depth of 228 ft bgs. The maximum deviation in the East-West plane was 1.2 inches, occurring below a depth of approximately 130 fl bgs. The results of the deviation survey indicate that the GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 64 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 verticality of the test well is wilhin the limits defined by the technical specificafions (6 inches per 100 ft of depth). A summary of the deviation survey is provided in Table 9. 7.5,8 Pumping Tests Two separate pumping tests were conducted on D/TW1/PW9 after the complefion of development pumping. The first test was a step drawdown test, conducted at three progressively increasing pumping rates, lo assess the specific capacity and efficiency of the well. The second lest was a 24-hour constant rate test conducted to obtain data from which to calculate aquifer transmissivity and storativity. Details of aquifer properties determined from the pumping tests are discussed in Section 7.5.8. During both tests, the pumping groundwater level, discharge rate, and sand content of the pumping well were closely monitored (see Appendix H). Groundwater levels were also measured in the following observation wells: D/B2/MW1 -S and -D (50 ft away); OW-11 (260 ft away); OW-1 (40 East) (290 ft away); OW-2 (140 West) (290 ft away); OW-1 Shallow (555 ft away); PW-1 (565 ft away); PW-2 (565 ft away); - PW-3 (390 ft away); 2A/B2/MW1-S and -D (2,200 ft away); GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 65 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 . 2B/B1/MW1 (2,000 ft away); • 3B/B1/MW1 (4,100 ft away); . 3B/B2/MW2-S and -D (4,100 ft away), and . 32/Bl/MWr(3,100ftaway). Data gathered from these observation wells were used to esfimate storafivity values for both the alluvial and bedrock aquifers and lo provide another measure of aquifer transmissivity. The field procedure for these tests followed the American Society for Tesfing and Materials (ASTM, 1994), standard test method D 4050. A summary of the groundwater levels measured in these wells using a manual electric sounder and pressure transducers before, during and after the pumping lest is provided in Appendix H. 7.5.8.1 Step-Drawdown Test 7.5.8.1.IStep-Drawdown Data Evaluation Methodology The purpose of the step drawdown lest is to determine formafion losses, well losses, and well efficiency, all necessary in determining the final pump design. In an acfively pumping well, the total drawdown in the well is composed of both laminar and turbulent head loss components. Laminar losses generally occur away from the borehole (where approach velocities are low), while turbulent losses are confined to the area in and around the immediate vicinity of the well screen and within the well bore. The tolal drawdown in a pumping well may be expressed as: Sw = BQ+ CQ^ "Drawdown in A Pumping Well" (1) where: Sw = Total drawdown measured in the well, [fl] GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 66 Geohydrologic Investigation -- Lower San Luis Rey River Valley 31 -Aug-04 B = Formation or aquifer loss coefficient, [fl/gpm] Q = Discharge rate of the well, [gpm] C = Well loss coefficient, [fl/gpm^] The first and second terms in equation (1) are referred to as formation, or aquifer loss'' (BQ) and well loss (CQ ), respectively. Formafion (i.e. aquifer) loss and well loss coefficients are determined from the step drawdown test. The lest procedure involves pumping "the well at mulfiple (at least three) discharge rates with each "step" being a fracfion of the maximum discharge. Analysis of the step drawdown data requires plotting the "specific drawdown" (Sw/Q) for each step against discharge rate. The formation loss coefficient (B) is the y-intercepl of the best-fit straight line through the specific drawdown data points. The slope of the line is equal to the well loss coefficient (C). Well Efficiency (E) is defined as the ratio of the formation (i.e. aquifer) loss component (BQ) to the tolal drawdown measured in the well (Sw) and is expressed as a percent: £ = 100-^ = ——— "Well Efficiency" (2) Sw \ + CQ/B where: E = Well Efficiency, [%] B = Formation or aquifer loss coefficient, [fl/gpm] Q = Discharge rate of the well, [gpm] Sw = Total drawdown measured in the well, [fl] 7 Aquifer loss is the head loss measured at the interface between the aquifer and the filter pack, The magnitude of the aquifer loss can be found from consideration of radial flow into the well and may be calculated, for example, using Jacob's equation. Well losses are turbulent flow losses which are head losses associated with the entrance of water into and through the well screen as well as those losses incurred as the flow moves axially towards the pump intake. These losses vary as the square of the velocity. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 67 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 C = Well loss coefficient, [ft/gpm ] 7.5.8.1.2Summary of Data A step drawdown test was performed for the Desaller Test Well D/TW1/PW9 on 16-Feb-04 at discharge rales of 1,124 gpm, 1,542 gpm, and 2,070 gpm (see Figure 21). Step-drawdown test data are summarized in Appendix H. The specific drawdown (s/Q) data summarized in the table below are plotted against the discharge rate (Q) on Figure 22 to assess formafion and well loss coefficients. Summary of Step-Drawdown Test Results - Desalter Test Well D/TW1/PW9 Step Discharge Rate Incremental Drawdown Drawdown Speciflc Drawdown m Qn. Am Sjii . (s/Q)„, [gpm] [ft] [ft] [ft/gpm] 1 1,124 21.4 18.7 . 0.0166 2 1,542 11.1 29.7 0.0193 3 2,070 11.3 41,7 0.0201 Results indicate a formafion loss coefficient (B) of 0.017 ft/gpm and a well loss coefficient (C) of 0.000002 ft/gpm^.. These coefficients were used to evaluate expected formafion and well losses at different well discharge rates as shown on the specific capacity and well efficiency plot (see Figure 23). As shown, al a discharge rale of 2,000 gpm, the specific capacity of D/TW1/PW9 is 47.4 gpm/ft, the formation loss is approximately 34.2 ft and the well loss is approximately 8.0 ft. The well efficiency at this discharge rate is approximately 81 percent (see Figure 23). GEOSCIENCE Support Services, Inc. 68 Telra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 7,5.8.2 Constant Rate Test 7.5.8.2,1 Pumping Test Procedure The field procedure for the constant rate pumping test followed the American Society for Tesfing and Materials (ASTM, 1994), standard test method D 4050. The pumping lest was conducted in three groundwater level monitoring phases: A pre-pumping phase, • A pumping (drawdown) phase, and A post-pumping (recovery) phase. The pre-pumping phase started at 11:30 AM on 15-Feb-04 and ended at 10:10 AM on 16-Feb-04 for a total of 22 hours and 40 minutes. At the start of this phase the Desalter Wells PW-1, PW-2 and PW-3 were shut down to allow groundwater level drawdown resulfing from pumping these wells to recover. Following a 6-hour step drawdown test (see Section 7.5.8.1.1), monitoring of the groundwater levels within the pumping well and the selected monitoring wells began at 7:37 AM on 17-Feb-04. The pumping (drawdown) phase started at 8:00 AM on 17-Feb-04 when the test pump within lest well D/TW1/PW9 was tumed on, and ended at 8:35 AM on 18-Feb-04 for a total of 24 hours and 5 minutes. An average discharge rate of approximately 1,860 gpm was achieved in the pumping well throughout the test. The post-pumping (recovery) phase started at 8:35 AM on 18-Feb-04 and ended at 1:00 PM on 18-Feb-04 for a tolal of 4 hours 25 minutes. Groundwater recovery was recorded within both the pumping well and the 16 monitoring wells during this phase. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 69 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 - Aug-04 Pumping Well The Desalter Test Well D/TW1/PW9 served as the pumping well for the constant rate pumping test. The location of this well is shown in Appendix A - Desaller Site. As described in Section 7.5.5, this well consists of a 16-inch diameter casing perforated from 100 to 220 ft bgs. The static groundwater level in the well was 13.94 ft below the measurement reference point al the start of the pumping phase of the test. Groundwater levels were measured during each lest phase using a down-hole pressure transducer set to collect measurements at 60-second intervals. During pumping, the discharge rate was monitored by reading the instantaneous discharge meter located at the pumping well. Discharge readings were displayed as gpm with a sensitivity of 1 gpm. Based on the discharge readings measured throughout the pumping period. Test Well D/TW1/PW9 pumped approximately 2.75 million gallons or 8.4 acre-ft of water at an average discharge rate of 1,860 gpm. Monitoring Wells A total of 16 existing wells located within the area of D/TW1/PW9 were used as monitoring wells during all test phases of the constant rate pumping test. These wells were selected based on their distance from the pumping well and on the aquifer in which il is screened. The following table summarizes the monitoring wells used for the constant rate pumping test: GEOSCIENCE Support Services, Inc. Tetra Tcch/San Diego County Waler Authority 70 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 D/TW1/PW9 Pumping Test - Monitoring Well Details Well Name Perforated Interval [ft bgs] Aquifer Screened Distance from Pumping Well D/TW1/PW9 [ft] Static Water Level [ft below reference point] D/B2/MW1-S* 85-140 Alluvium 50 13.88 D/B2/MW1-D* 190-270 Bedrock 50 15.31 OW-11* 230-250 Al 1 u vi um/B edrock 260 22.72 OW-1 (40 EasO 30-40 Alluvium 290 17.91 OW-2 (140 West) 130-140 Alluvium 290 15.84 PW-3 100-142 Alluvium 390 18.72 OW-1 Shallow 30-40 Alluvium 555 13.74 PW-1 100-160 Alluvium/Bedrock 565 19.40 PW-2 100-140; 160-180 Alluvium/Bedrock 565 19.19 2B/B1/MW1* 90-120 Alluvium 2,000 13.94 2A/B2/MW1-S 25-90 Alluvium 2,200 12.27 2/VB2/MW1-D 210-300 Bedrock 2,200 11.96 32/Bl/MWl • 180-210 Alluvium 3,100 14.21 3B/BI/MW1 70-100 Alluvium 4,100 21.76 3B/B2/MW2-S 170-300 Bedrock 4,100 20.70 3B/B2/MW2-D 400-440 Bedrock 4,100 19,60 * Wells in which transducers were installed. Groundwater levels were measured in D/B2/MW1-S and D/B2/MW1-D, OW-11, and 2B/B1/MW1 using a downhoie pressure transducer sel to record measurements at 60-second intervals. Groundwater levels were measured in the remaining monitoring wells using a manual sounder. 7.5.8.2.2 Constant Rate Data Evaluation Methodology Theis Equation Calculafion of aquifer parameters from pumping test data is based on analytical solufions of the basic differenfial equation of groundwater flow that can be derived from fundamental laws of GEOSCIENCE Support Services. Inc. Tetra Tech/San Diego Couniy Water Authorily 71 Geohydrologic Inve.stigation - Lower San Luis Rey River Valley 31 -Aug-04 physics. One of the most widely used solutions of this equation for non-steady radial flow to wells is the "Theis Equafion": s{rj) = ^-~^W{u) "Theis Equation" (1) where; s(r,l) = Drawdown in the vicinity of an artesian well, [ft] r = Distance from pumping well, [ft] Q = Discharge rate of pumping well, [gpm] T = Transmissivityof aquifer, [gpd/ft] W(u) = "Well function of Theis" u = 1.87xr^xS/(Txt) Jacob's Straight-Line (Modified Theis Non-Equilibrium) Method According lo Jacob (1950), for small values of "u" (u < 0.05), the Theis equation may be approximated by: . . 264Q, s(r,t)=^-^\og 0.3 Tt J "Jacob's Equation" (2) Jacob's equation is valid for use for most geohydrologic problems of pracfical interest, is easier to use than the Theis equafion, and involves a simple graphical procedure to calculate transmissivity and storafivity. This method (D 4105) is summarized by ASTM (1994). GEOSCIENCE Support Services, Inc. Telra Tcch/San Diego County Waler Authority 72 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Transmissivity (T, in gpd/ft) can be calculated as: T-'^ (3) where: Q = Pumping rate, [gpm] Ai' = Change in drawdown over one log cycle of lime, [ft] Storativity can be calculated as: S-'-^ ' (4) r' where: T = Transmissivity, [gpd/ft] to = Time at the zero-drawdown intercept, [days] r = Radial distance from the pumping well, [ft] Jacob's Straight-Line Applied to Recovery The procedure used for recovery data analysis is idenfical to that used during the pumping phase except that time is measured after the pump has stopped and "calculated recovery" is used instead of drawdown. Calculated recovery is the difference between the extrapolated time-drawdown curve and the residual drawdown. Residual drawdown is the difference between the slafic water level and depth to waler after the pump is stopped. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 73 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Jacob's Straight-Line Applied to Distance Drawdown The basic procedure used to evaluate time-drawdown data can also be used with distance-drawdown data to derive transmissivity and storafivity. In this case, however, the equafions used to evaluate the data are: As and S-'-^ (6) r. where: t = Time at which drawdown measurements were taken, [days] ro = Intercept where drawdown is zero, [ft] Hantush Inflection Point Method for Leaky Aquifers For semi-confined aquifers, fime drawdown data may show recharge trends indicative of a leaky aquifer system. In these cases, the data exhibit a reverse "S" shape. In these cases, the Hantush inflecfion point method can be used lo evaluate transmissivity, storafivity and leakage using the following equations: 229Q f T = -K, GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Waler Aulhorily 74 Geohydrologic Investigation - Lowcr San Luis Rey Rivcr Valley 31-Aug-04 and 5 = ( r ^O.llTt: B r (8) and ( 1 ^ V 7.4SB' ^day^ (9) where: T = Transmissivity, [gpd/ft] Q = Pumping rate, [gpm] = Radial distance from the pumping well, [ft] = Drawdown at the inflection poinl, [ft] = Modified Bessel funcfion of the second kind and order zero, = Leakage factor, [ft] = Time at the inflecfion point, [days] —7 = Leakance, [/day] r Sm Ko B The leakance value was also esfimated from the distance drawdown data using the relafionship: fc_ o.nr r' (10) (Hantush, 1964) GEOSCIENCE Support Services, Inc. 75 Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 where: ro - Intercept where drawdown is zero from the distance drawdown plot, [ft] 7.5.8.2.3 Summary of Data The 24-hour constant rale lest for D/TW1/PW9 started on 17-Feb-04 and finished on 18-Feb-04 (see Figure 24). The pumping test was conducted al an average discharge rate of 1,860 gpm. A summary of the aquifer parameters estimated from the various analyses of the pumping test data is provided in Table 10. Analysis of the D/TW1/PW9 pumping test data indicates that groundwater level drawdown in the test well was 2.7 fl of drawdown per log cycle (see Figure 24). The Jacob's straight-line method was used to analyze the fime-drawdown data and results show a Iransinissivity of approximately 181,000 gpd/ft. The Jacob's straight-line method applied to recovery data from D/B2/MW1-S and OW-2 (140 West), which are perforated at similar depths as the test well, yields transmissivities ranging from approximately 153,000 to 162,800 gpd/ft, and storafivilies ranging from 0.0007 lo 0.004 (see Figures 25 and 26). Distance-drawdown analysis al 1,000 minutes since the pump was started yields a transmissivity of approximately 138,000 gpd/ft and a storativity of 0.003 (see Figure 27). 7.5.9 Groundwater Sample Collection Groundwater samples were collected al the end of the 24-hour constant rate pumping test and submitted to Del Mar Analytical for consfituents listed under Tide 22 of the California Code of Regulations. A summary of the consfituents tested, their detecfion limits and analyfical results of testing are included in Appendix D. GEOSCIENCE Support Services, Inc, Tetra Tech/San Diego County Water Authorily 76 Geohydrologic Jnvesligalion - Lowcr San Luis Rey River Valley 31-Aug-04 7.5.10 Spinner (Flowmeter) Survey Approximately one.hour prior to the end of the constant rate pumping lest, a flowmeter (or "spinner") survey, was conducted by Pacific Surveys, Inc.,'in the test well (D/TW1/PW9). The test provides a relative indication of the contribution of flow to the well from differing depths. The survey was conducted while D/TW1/PW9 was being pumped at a rate of 1,800 gpm. The flowmeter survey data are provided in the geophysical borehole logs in Appendix E. Results of the flowmeter survey show that almost all of the groundwater flow contribufion to the well is occurring between depths of approximately 100 and 160 ft bgs (see Figure 28). 7.5.11 Downhoie Video Survey Pacific Surveys, Inc. completed a video log of the posl-construcfion condifion of the test well on 27-Feb-04 to serve as a permanent record of the construcfion details and condition of the well following development and testing. The video survey showed the well casing and screen lo be clean and in good condifion. 7.6 Oceanside Desalter Pumping Test A constant rate pumping test was performed at the Cily of Oceanside Desaller Plant on 20, 21, and 22-Oct-03. The test consisted of pumping City of Oceanside Wei! PW-3 for 40 hours at a constant rate of approximately 995 gpm (see Appendix A-Desalter Site for well locafion). The primary purpose of the constant rate pumping test was to obtain data from which to estimate aquifer properties of the alluvial aquifer in the vicinity of the Oceanside Desalter. However, the test data was also used to assess the relafionship between the alluvial aquifer and the underiying GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Waler Authority 77 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 bedrock aquifer as well as the relationship between the alluvial aquifer and the San Luis Rey River, 7.6.1 Pumping Test Procedure The field procedure for the pumping test followed the American Society for Tesfing and Materials (ASTM, 1994), standard lest method D 4050. The pumping test was conducted in three groundwater level monitoring phases: • A pre-pumping phase, A pumping (drawdown) phase, and A post-pumping (recovery) phase. The pre-pumping phase started at 12:00 PM on 19-Oct-03 and ended at 4:00 PM on 20-Oct-03 for a total of 16 hours. At the start of this phase the Desalter Wells PW-1, PW-2 and PW-3 were shut down to allow groundwater level drawdown resulfing from pumping these wells lo recover. Monitoring of the groundwater levels within the pumping well and the selected monitoring wells began at 8:20 AM on 20-Oct-03. The pumping (drawdown) phase started al 4:00 PM on 20-Oct-03 when pumping well PW-3 was tumed on, and ended at 8:00 AM on 22-Oct-03 for a total of 40 hours. The pumping well was set to a discharge rate of approximately 995 gpm. Groundwater pumping levels and discharge rale were measured throughout this phase. The post-pumping (recovery) phase started at 8:00 AM on 22-Oct-03 and ended at 2:20 PM on 22-Oct-03 for a total of 6 hours 20 minutes. Groundwater recovery was recorded within both the pumping well and the 14 monitoring wells during this phase. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 78 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Pumping Well Cily of Oceanside Well PW-3 served as the pumping well for the constant rate pumping test. The location of this well is shown in Appendix A, Desaller Site). This well consists of a 16-inch diameter casing perforated in the alluvial aquifer from 100 to 142 ft bgs. The static groundwater level in the well was 19.25 ft below the measurement reference poinl at the start of the pumping phase of the test. Groundwater levels were measured during each test phase using a down-hole pressure transducer set to collect measurements at 15-second intervals. During pumping, the discharge rate was monitored by reading the instantaneous discharge meter located in the PW-3 panel box. Discharge readings were displayed as gpm with a sensitivity of 1 gpm. Discharge readings were also monitored by City of Oceanside technicians at the Desalter Plant. These readings were recorded every 3 hours during the durafion of the pumping period using the facility's telemetry system. Based on the discharge readings measured throughout the pumping period, Well PW-3 pumped approximately 2.39 million gallons or 7.3 acre-ft of water at an average discharge rate of 995 gpm. Monitoring Wells A total of 15 existing well's located within the area of the Desalter Plant were used as monitoring wells during all lest phases of the constant rate pumping lest. These wells were selected based on their distance from the pumping well and on the aquifer in which il is screened. The following table summarizes the monitoring wells used for the constant rate pumping test: GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Waler Authority 79 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 PW-3 Pumping Test - Monitoring Well Details Well Name Perforated Interval [ft bgs] Aquifer Screened Distance from Pumping Well PW-3 [ft] Static Water Level [ft below reference point] PW-2* 100-140;160-180 Alluvium/Bedrock 217 19,78 OW-1 (40 East)* 30-40 Alluvium 130 18.19 OW-lShallow 30-40 Alluvium 480 15.60 OW-2 (140 West)* 130-140 Alluvium 130 17.17 OW-11 230-250 Bedrock 170 24.10 D/B2/MW1-S* 85-140 Alluvium 370 12.70 D/B2/MWND* 190-270 Bedrock 370 20.50 2A/B2/MW1-S 25-90 Alluvium 2,700 10.83 2A/B2/MW1-D 210-300 Bedrock 2,700 9.85 2B/MW1* 90-120 Alluvium 2,150 24.95 3B/MW1 70-100 Alluvium 3,800 18.60 3B/B2/MW2-S 170-300 Bedrock 3,800 19.32 3B/B2/MW2-D 400-440 Bedrock 3,800 18.15 11C/B1/MW1-S 180-250 Alluvium 5,600 38.33 11C/B1/MW1-D 300-410 Bedrock 5,600 34.93 * Wells in which transducers were installed. Groundwater levels were measured in PW-2, OW-1 (40 East), OW-2 (140 West), D/B2/MW1-S, D/B2/MW1-D and 2B/MW1 using a downhoie pressure transducer set to record measurements at 15-second intervals. Groundwater levels were measured in the remaining monitoring wells using a manual sounder. 7.6.2 Data Evaluation Methodology The methodology for evaluating the constant rate test data from PW-3 is as described in Section 7.5.8.2.1. Graphs of lime-drawdown and distance-drawdown data from the pumping and monitoring wells in which pressure transducers were installed are shown on Figures 29 through 35. Aquifer parameter data obtained from the test are summarized in Table 10. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 80 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 7.6.3 Summary of Data Transmissivity values of the alluvial aquifer obtained from the pumping test is approximately 164,000 gpd/ft as estimated from the recovery data measured in pumping well PW-3 (see Figure 29) to 211,000 gpd/ft from the drawdown data measured in monitoring wells PW-2, OW-2 (140 West), and D/B2/MW1-S (see Figures 30 through 32). These results are generally within the range (although slightly higher) of transmissivity values obtained from previous pumping test analyses for this area (approximately 129,000 to 141,000 gpd/ft; Stetson, 1991). Transmissivity values obtained from the pumping test analysis were converted to hydraulic conductivity by dividing each respecfive transmissivity by the assumed aquifer thickness. The aquifer was estimated to extend from approximately 80 fl bgs (the base of the 10-ft thick "sandy clay" identified in the driller's log for PW-3) to 142 ft bgs (the bottom of the perforated interval for PW-3) for a total thickness of 62 fl. This interpretation is generally supported by the lithology of the continuously cored borehole for D/Bl, located approximately 100 ft lo the northeast of PW-3. It is implied that, in using this assumed aquifer thickness, the aquifer being tested is confined or semi-confined, given that the groundwater polenfiometric surface is approximately 20 ft below ground surface or approximately 60 ft above the bottom of the sandy clay (confining) layer identified from the driller's log. Hydraulic conductivity values ranging from 2,113 to 3,403 gpd/fC (see Table 11) were obtained for the alluvial aquifer based on these assumptions. Storativity values obtained from the non-pumping monitoring wells ranged from 0.0004 lo 0.0014 (see Table 11). These data support the assumpfion that the alluvial aquifer in the vicinity ofthe Oceanside Desalter is confined lo semi-confined. Observation of the drawdown data from monitoring wells PW-2 and OW-2 (140 West) (see Figures 30 and 31) show thai the data form the "S" shaped curve indicative of a leaky aquifer. Leakance ranged from 0.00012/day to 0.157/day as esfimated from lime-drawdown data using GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 the Hantush inflection point method. From the distance-drawdown plot shown on Figure 36, the leakance was estimated to be 0,001/day. A summary of the aquifer parameters esfimated from the various analyses of the constant rate pumping test data is provided in Table 11. GEOSCIENCE Support Services, Inc. . Tetra Tech/San Diego County Water Authority 82 Geohydrologic Investigation -Lower San Luis Rey River Valley 3I-Aug-04 8.0 RESULTS OF FIELD INVESTIGATION PROGRAM - MISSION BASIN 8.1 Stratigraphy 8,1.1 Alluvium Unconsolidated alluvial sediments encountered in the Mission Basin during the Phase 2 field investigations are typical of sediments associated with a meandering stream system such as the San Luis Rey River. As indicated in the lithologic logs (see Appendix B), the alluvium ranges in thickness from approximately 53 to 216 ft. The origin of the alluvial sediments appears lo be granific rock (quartz, feldspar, mica), presumably weathered from the Peninsular Ranges to the east of the Mission Basin. The sand and gravel are typically medium to poorly sorted and are sub-angular lo sub-rounded, suggesfing significant transport prior to deposition. The alluvial sediments in the north-central portion of the basin (generally north of the Oceanside Desaller Facility between Sites 3B and 9A) have relafively high percentages of silt and clay, which are indicative of off channel flood plain deposits (see Appendix B; boring logs for Sites 3B, 3C, and 11; see also Plate 1), Alluvial sediments along the southem margin of the Mission Basin consist of predominantly coarse-grained deposits indicative of stream channel deposition (see Appendix B; boring logs for Sites 1, 7A, lOA, 13A, and 32). Although some silt layers are present in this area, the predominant sediment type is sand with some isolated gravel layers. Variafions in the thickness of alluvium across the Mission Basin support the deposifional environments suggested by the lateral variation of sediment types. The alluvial thickness generally increases from north lo south (see Figure 7; Plate 1). Thus, the alluvial flood plain deposits (silt and clay) occur in the shallowest portion of the basin, while the channel deposits (predominantly sand and gravel) occur in the deepest portion of the alluvial basin. This interpretation suggests that the course of the San Luis Rey River has historically been to the south of its current course. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 83 Geohydrologic Investigation - Lower San Luis Rey River Valley 3 i -Aug-04 In the central and westem porfions of the Mission Basin, layers of interbedded silt and clay having low permeability separate the shallow alluvial aquifer from the deep alluvial aquifer forming an aquitard lhal results in confined condifions in the deeper aquifer (see Figure 37). The aquitard consists primarily of sandy silt and sandy clay that ranges in thickness from approximately 10 to 30 fl (see Plate 1). Analysis of the consolidation potential of samples of the aquitard from the Desalter site and Sites 2A and IIC indicate that the greatest potenfial for consolidation, as indicated by the presence of expansive clay in the sample, is at Sites 2A and I IC (see Table 4; Appendix C). However, given the relatively thin aquifer above the aquitard and the limited thickness of the aquitard itself in the vicinity of Sites 1 IC and 2A, the potenfial for consolidafion (which could lead to land surface subsidence under conditions of prolonged groundwater level drawdown) is relatively low. 8.1.2 Bedrock Bedrock was encountered in all twenty-two^ exploratory boreholes drilled in the Mission Basin al depths ranging from 53.5 lo 222 ft bgs (see Table 2; Appendix B). As described in Secfion 4.2, two general types of bedrock were encountered: granific bedrock (identified as the Bonsall Tonalite) associated with the Southern Califomia batholith that outcrops to the east of the Mission Basin, and sedimentary bedrock of the La Jolla Group with outcrops to the north and south of the Mission Basin, and San Onofre Breccia with outcrops in western Mission Basin. 8.1.2.1 Granitic Bedrock Granitic bedrock was encountered during the drilling of boreholes 13/Bl and 13A/B1 located in the eastem portion of the Mission Basin (see Figure 3; Appendix B; Plate 1). This bedrock is correlafive with the Bonsall Tonalite, which outcrops to the east of the sites (see Figure 6). The ^ Although a record of the lithology encountered in borehole IB al Site 1 was not obtainable, it is presumed that bedrock was encountered based upon the total depth drilled and its close proximity to boreholes (A and }C. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 84 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 granitic rock was encountered at depths of 146 and 53.5 fl bgs al Sites 13 and 13A, respecfively. The granific rock in this area of the Mission Basin is light gray and medium-grained, with numerous randomly oriented gypsum-filled fractures. The upper portion of the tonalite shows little to no weathering, suggesting that little secondary porosity is available lo transmit waler in this formafion. 8.1.2.2 Sedimentary Bedrock Sedimentary rock of the La-Jolla Group was encountered in boreholes drilled during the Phase 2 field investigafions west of Site 13 in the Mission Basin. In general, the sedimentary bedrock consists of alternating layers of sandstone and siltstone and/or claystone of varying degrees of cementation. The sandstone is typically white lo light-gray or light-brown in color with medium to coarse-grained sand and minor localized fine gravel (see Appendix B). The claystone was generally fissile and harder than the sandstone; although, sandstone units encountered in borehole 2A/B2 (Site 2A) al approximately 100 and 120 ft bgs were unusually well cemented and very hard. A third type of sedimentary rock that was commonly encountered consisted of a gray- to Ught brown-colored silty claystone with minor amounts of gravel. Significant iron oxide alteration encountered at depths below 120 ft was visible in bedrock core samples in many boreholes, especially in borehole 2A/B2 at Site 2A. Marine fossils were not encountered in any of the borehole samples, suggesfing these deposits are possibly of a continental origin. In the western portion of the Mission Basin (Site 1), the first encountered bedrock consisted of clasfic sedimentary rocks of the San Onofre Breccia. The breccia encountered in Site 1 boreholes during Phase 2 drilling activities is very dense, greenish-gray to olive in color with a varying matrix of well-cemented, fine to coarse-grained sand with silt and clay. The thickness of the granific and sedimentary bedrock encountered during the Phase 2 drilling program was not determined. However, according to DWR (1967) the La Jolla Group may be as thick as 1,650 ft. In addifion, the San Onofre Breccia is associated with a deep marine trough GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Waler Authorily 85 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 (present day area ofthe Santa Monica-Channel Islands) that was filled widi 15,000 ft of Miocene age sediments (Norris and Webb, 1990). 8.2 Aquifer Systems Phase 2 drilling and testing has verified lhal groundwater within the Mission Basin occurs in both the alluvial sediments and the sedimentary bedrock underlying these sediments. Historically, it has been assumed that the sedimentary bedrock of the La Jolla Group does not yield appreciable amounts of water to wells and, accordingly, the base of the Mission Groundwater Basin was assumed to be the contact between the unconsolidated alluvium and the sedimentary bedrock (see Figure 7). Depth-specific aquifer tesfing within the sedimentary bedrock in the vicinity of the Oceanside Desalter Site confirmed the previous assumptions on the relafive yield of this aquifer. However, analysis of bedrock sediment cores at other sites (e.g. Site 2A), suggest that this formafion may locally be permeable enough to yield appreciable amounts of groundwater to welis. Given these findings, two general aquifer systems are described for this report: the alluvial aquifer system and the bedrock aquifer system. The alluvial aquifer system comprises the principal water-bearing deposits (i.e. aquifers) within the Mission Basin. The thickness of the alluvial aquifer ranges from 0 ft al the margins of the basin to greater than 200 ft in the southem (deepest) portions of the basin (e.g. Site 1 and Site 32). The lateral boundaries of the groundwater basins are approximated by the alluvium/bedrock contact at the ground surface as shown on Figure 6. The bedrock aquifer system consists of the loosely consolidated sandstone layers within the La Jolla Formation beneath the unconsolidated alluvium. The lateral and vertical extent of this aquifer system has not been defined, but likely extends beyond the boundaries of the Mission Groundwater Basin defined by the unconsolidated alluvium. If this aquifer was determined to be significantly permeable enough to store appreciable amounts of groundwater and the characteristics of groundwater flow were such that the area was receiving recharge from outside GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Waler Authority 86 Geohydrologic Investigation - Lower San Luis Rey River Valley _ 31-Aug-04 the boundaries of the groundwater basin as currently defined, then current estimates of the volume of groundwater in storage as well as the safe yield of the basin would need lo be reevaluated. However, given the limited amount of data available for this aquifer, it is premature to speculate on the implicafions of this groundwater reservoir on the amount of groundwater in storage or the safe yield of the Mission Basin. Thus, for this report, esfimates of groundwater storage and safe yield for the Mission Basin are based on the alluvial aquifer only until additional geohydrologic data on the bedrock aquifer can be collected. 8.2.1 Shallow Alluvial Aquifer The alluvial aquifer system has been divided into two aquifers based on observed differences in lithology and groundwater levels in wells. These alluvial aquifers have been designated as "shallow" and "deep". The shallow alluvial aquifer occurs throughout the Mission Basin in the upper 60 to 100 ft of alluvial sediments. The lithology of these aquifer sediments varies across the basin. In the westem portion of the basin and in the vicinity of the Oceanside Desalter, the shallow alluvial aquifer consist primarily of fine to medium-grained sand and silty sand that is interbedded with silt and some clay (see Appendix B; boring logs for D/Bl and D/B2/MW1). In the north central portion of the basin, the shallow aquifer is predominantly sill and silt/sand mixtures with interbedded clay (see Appendix B; boring logs for 3B/B2/MW2 and 3C/B1). In the northwestern portion of the basin (northeast of Site 9A), the shallow aquifer is predominanfiy sand and gravel with lesser amounts of silt (see Appendix B; boring logs for Sites 13 and 13A). GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 87 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 8.2.1.1 Groundwater Occurrence and Flow The shallow aquifer is unconfined with groundwater levels ranging from approximately 10 to 20 ft bgs. Groundwater flow is from the northeast lo the southwest (see Figure 8), in approximately the same direction as surface water flow in the San Luis Rey River. The groundwater gradient ranges from 0.0017 to 0.0025 ft/fl (9 to 13 ft/mile) with the steepest gradient in the northeast portion of the Mission Basin (see Figure 8). There is no evidence that faults mapped in the lower Mission Basin are acting as barriers to groundwater flow. During the Oceanside Desalter PW-3 pumping test (see Section 7.6), groundwater levels measured in OW-1 (40 East), which is perforated in the shallow alluvial aquifer (30 to 40 fl bgs), showed only minor drawdown (less than 1 foot) while pumping from the deep alluvial aquifer (peribrated 100 to 142 ft bgs; see Appendix H). In contrast, monitoring wells screened in the deeper alluvial aquifer (see OW-2 (140 West)) showed greater than 5 fl of drawdown during the same test. These data indicate that the shallow alluvial aquifer, where present, is in limited hydraulic communication with the deep alluvial aquifer. 8.2.1.2 Source of Recharge Due to the unconfined nature of the shallow alluvial aquifer, it is likely in hydraulic communication with the San Luis Rey River throughout most of the Mission Basin and receives most of its recharge from this source. Groundwater levels in Desalter Wells OW-1 and OW-1 (40 East), which are both perforated within the shallow alluvial aquifer, rise noficeably during periods of increased precipitafion and corresponding increased stream flow along the San Luis Rey River (see Figure 38). Similarly, groundwater levels measured in monitoring wells in the northeastem portion of the Mission Basin also rise during the late winter and spring months in response to precipitation during this part of the year (see Figure 39). Although some recharge to the shallow alluvial aquifer is expected from direct infiltration of precipitation on the land surface, the San Luis Rey River is likely the. predominant source of water to this aquifer. GEOSCIENCE Support Services. Inc. Tetra Tcch/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 8.2.1.3 Aquifer Characteristics Geohydrologic properties for the shallow alluvial aquifer system have been evaluated based both on pumping test data and empirical evaluation of lithologic descripfions of the sediments. In the northeastem Mission Basin, pumping tests at Cily of Oceanside Wells 4 and 5 suggest alluvial aquifer transmissivities are in the range of 70,000 lo 130,000 gpd/ft and hydraulic conductivities range from 1,100 to 2,000 gpd/ft^ (Geopacifica, 1995). Although the transmissivifies derived from the pumping tests at these wells are difficult to interpret because the groundwater level drawdown appears to be influenced by recharge from the San Luis Rey River, the relatively high permeability of the aquifers suggested by the pumping tests is consistent with the relafively high percentage of sand and gravel noted in boring logs in the northeastem Mission Basin (see Appendix B). Although no data are available, storafivilies (i.e. specific yield) in this area are also expected to be relafively high (25 lo 30 percent), which is consistent with unconfined sand and gravel aquifers in nearby groundwater basins (Johnson, 1967). In the vicinity of the Oceanside Desaller, the relafively fine-grained nature ofthe shallow aquifer suggests lower transmissivities and hydraulic conductivities for this aquifer in this area than in the northeastem Mission Basin. Although no data are available from field tests, typical hydraulic conductivities for these types of sediments (fine lo medium-grained sand and silty sand) range from approximately 0.5 to 5,000 gpd/ft^ (Freeze and Cherry, 1979). The specific yield of the shallow alluvial aquifer, based on the fine-grained nature of the sediments in the vicinity of the Oceanside Desalter is expected to be in the range of 10 lo 20 percent (Johnson, 1967). 8.2.2 Deep Alluvial Aquifer The deep alluvial aquifer generally occurs beneath most of the westem portion of the Mission Basin, south of Sites 3B and 3C and west of City of Oceanside Borehole No. 8 (see Plate 1). The deep alluvial aquifer is approximately 30 to 150 ft thick with the thickest porfions occurring in the vicinity of Sites 1 and 32 (see Plate 1). The sediments of this aquifer typically consist of fine GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 89 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 to coarse-grained sand with isolated gravelly layers. The thickness of the aquifer increases from north to south with the greatest thickness idenfified at Sites 1 and 32. 8.2.2.1 Groundwater Occurrence and Flow The deep alluvial aquifer is semi-confined to confined with groundwater levels generally ranging from approximately 15 lo 20 ft bgs (see Appendix M; OW-2 and D/B2/MW1-S). The groundwater flow direction is similar to that of the shallow alluvial aquifer, flowing from northeast to southwest at a gradient of 0.0017 to 0.0025 ft/ft (9 to 13 ft/mile) (see Figure 8). There is no evidence that faults mapped in the lower Mission Basin are acting as barriers to groundwater flow. 8.2.2.2 Source of Recharge Under slafic (i.e. non-pumping) condifions, the primary source of natural recharge to the deep alluvial aquifer is likely groundwater underflow from the up-gradient portions of the Mission Basin. Given the deeper nature of this aquifer and the presence of an overlying confining unit (aquitard), this aquifer does nol likely receive a significant amount of natural recharge direcfiy from the San Luis Rey River. During periods when the Desalter pumping wells are off (such as what was measured immediately prior to the D/TW1/PW9 and PW-3 pumping tests), the hydraulic head in the deep alluvial aquifer is higher than the head in the shallow alluvial aquifer, indicafing that the natural hydraulic gradient is upward. Thus, under non-pumping conditions, the shallow aquifer receives some limited recharge from the deeper aquifer from leakage through the aquitard. During periods when the Oceanside Desalter pumping wells are in operation, the hydraulic head in the deep alluvial aquifer is lower'than the head in the shallow alluvial aquifer, which acts to GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 90 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 induce recharge into the deeper aquifer from the shallow aquifer (see Figure 40). The influence of deep alluvial aquifer pumping on groundwater levels in the shallow alluvial aquifer has been shown from the PW-3 pumping lest, as discussed in Secfion 8.2.4. This pumping influence has also been demonstrated to extend to wells in the immediate vicinity of the San Luis Rey River (see PW-3 pumping test hydrographs for Sites 2A and 2B; Appendix H). These data indicate that pumping from the deep alluvial aquifer has an impact on groundwater levels directly beneath the San Luis Rey River. 8.2.2,3 Aquifer Characteristics Geohydrologic properties for the deep alluvial aquifer system have been evaluated based on the 24-hour constant rate pumping test conducted for D/TW1/PW9 and the 40-hour constant rate pumping test conducted for Oceanside Desalter Well PW-3 (see Sections 7.5.8.2 and 7.6). Based on these tests perfonned during the Phase 2 field invesfigations, the transmissivity of the deep alluvial aquifer ranges from approximately 131,000 to 211,000 gpd/ft (see Tables 10 and 11). The corresponding hydraulic conductivities range from approximately 2,100 lo 3,400 gpd/ft in the immediate vicinity ofthe Oceanside Desalter (PW-3 pumping test, Section 7.6.3) and 1,200 to 1,700 gpd/ft^ to the south of the Oceanside Desalter (D/TW1/PW9 pumping test. Table 10). The storafivity of the aquifer is esfimated to range from 7.0 x 10"* lo 3.0 x 10'^ suggesting semi-confined aquifer condifions. Although a constant rate pumping test was conducted for well IC/TWl al Site 1, which is perforated within the deeper alluvial aquifer, the relafively low discharge rate and limited pumping time did nol allow for reliable estimates of geohydrologic aquifer properties. Given the relatively coarse-grained nature of the aquifer sediments, it is likely that the hydraulic conductivity of these sediments is similar to, or greater than, the hydraulic conductivity of the sediments in the vicinity of D/TW1/PW9. The corresponding transmissivity would also be greater given the thicker sequence of aquifer sediments at Site 1. GEOSCIENCE Support Services, Inc. Telra Tech/San Diego Couniy Water Authority 91 Geohydrologic Investigation - Lower San Luis Rey River Valley • 31 -Aug-04 8.2.3 Bedrock Aquifer The bedrock aquifer consists of the permeable sandstone layers within the La Jolla Group sediments, which underlie almost all of the Mission Basin. The lateral extent of the aquifer is unknown but it likely extends beyond the boundaries of the Mission Groundwater Basin, as defined by the unconsolidated alluvium. Undisturbed cores of bedrock sediments that appeared to have the most poteniial to yield groundwater consisted of light-colored, medium- to coarse-grained sandstone. In most cases, the sandstone was weakly cemented (semi-consolidated) and consisted primarily'of quartz with minor feldspar and mafic minerals, indicative of the granific terrain in the upper elevations of the San Luis Rey River watershed. Fine-grained material was present in all cores of the sandstone, usually consisfing of fine sand, silt, and clay (weathered feldspar). Interpretation of sandstone layer stratigraphy from borehole intercepts suggests that individual sandstone/layers are laterally confinuous in the north-central portion of Ihe Mission Basin (see Plate 1). The sedimentary bedrock aquifer was explored to a maximum depth of approximately 500 ft bgs (see Plate 1; Site 1 IC/Bl). Sandstone layers were encountered at the maximum depths explored and it is Hkely, given the mapped thickness of the unit (1,650 ft; DWR, 1967) that addifional sandstone layers exist below this depth. Thus, the maximum depth of the bedrock aquifer system remains unknown. 8.2.3.1 Groundwater Occurrence and Flow The bedrock aquifer is confined with groundwater levels generally ranging from approximately 12 ft bgs ,in the center of the Mission Basin (see 2A/B2/MW1-D; Appendix M and Plate 1) to 40 ft bgs al Site IIC (see Appendix M and Plate 1). In areas of the basin not influenced by pLimping from the Oceanside Desalter (e.g. Sites IIC and 3B), the groundwater levels in the bedrock aquifer are higher than groundwater levels in the deep and shallow alluvial aquifers. In the immediate vicinity of the Oceanside Desalter, bedrock aquifer groundwater levels are also GEOSCIENCE Support Services, Inc. Telra Tech/San Diego Couniy Water Authority 92 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 typically higher than those of the shallow and deep alluvial aquifers except during periods of prolonged pumping from Oceanside Desalter wells (see Plate 1). The data available to assess the groundwater flow direcfion in the bedrock aquifer indicates that groundwater flows toward the center of the Mission Basin (see Plate 1). 8.2.3.2 Source of Recharge The source of recharge for the bedrock aquifer in the Mission Basin could not be determined based on the data collected during the Phase 2 field investigation program. 8.2.3.3 Aquifer Characteristics The only data related to the permeability of the sandstone layers of the bedrock aquifer are laboratory permeability results of undisturbed samples collected from discrete depths in boreholes 2A/B2, 3B/B2, and D/B2. Reported saturated hydraulic conductivity (vertical) of the samples analyzed ranged from 5.0 x 10'^ cm/s (0.2 gpd/ft^) in the sample from 2A/B2 at 241 fl bgs lo 7.5 X 10'^ cm/s (1.6 gpd/ft^) in the sample from 3B/B2 at 252 ft bgs (see Table 4, Appendix C). It should be emphasized that the laboratory results represent vertical permeability and that the horizontal permeability of the samples are likely as much as an order of magnitude greater. Groundwater level data obtained from the aquifer zone testing in the pilot borehole for the Desaller Test Well D/TW1/PW9 provides an indirect indication of the permeability of the bedrock aquifer. Pumping from the two bedrock zones resulted in maximum aquifer yields of 6 gpm (Zone No. 1) and 15 gpm (Zone No. 2), as compared to greater than 200 gpm for the alluvial zone (Zone No. 3). These tests suggest that the sandstone bedrock in the vicinity of the Oceanside Desalter has a relatively low permeability. Maximum groundwater level drawdown in well GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 93 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 D/B2/MW1-D (located 50 ft from the pumping well) was approximately 18 ft during Zone No. 1 pumping and approximately 63 fl during Zone No. 2 pumping (see Figure 41). Groundwater level recovery in the bedrock monitoring well (D/B2/MW1-D) also required several days, which suggests very low permeability, consistent with the soil laboratory permeability analysis and zone testing described above. The flowmeter survey, conducted at the end of the 24-hour constant rate pumping test in D/TW1/PW9, indicates that almost all of the flow to the well is from the alluvial aquifer. No flow contribufion was observed from the bottom of the perforations of the well (220 ft bgs) lo approximately 160 ft bgs. With the alluvium/bedrock contact at approximately 141 ft bgs, il appears that the upper 7 ft of the sandstone bedrock contributed some flow to the well. However, the majority of the flow contribution was from the alluvial aquifers between 140 and 100 ft bgs. These data, together with the aquifer zone tesfing results, indicates that the permeability of the bedrock is significantly lower than the permeability of the alluvium. 8.2.4 Relationship Between Bedrock and Alluvial Aquifers Aquifer pumping test results at Oceanside Desalter Well PW-3 and aquifer zone testing in the pilot borehole for D/TW1/PW9 indicate that pumping from the deep alluvial aquifer impacts groundwater levels in the bedrock aquifer and vice versa. During the PW-3 pumping test, as much as two fl of groundwater drawdown was measured in monitoring well OW-11 (see Figure 42), which is located approximately 170 ft from the pumping well and is screened completely within the bedrock aquifer (PW-3 is screened completely within the deep alluvial aquifer). Groundwater levels in OW-11 also recovered promptly after pumping. These data suggest that the bedrock aquifer is in hydraulic continuity with the alluvial aquifer in the immediate vicinity of the Oceanside Desalter site. Groundwater levels in bedrock aquifer monitoring well D/B2/MW1-D (perforated from 190 to 270 ft bgs), which is located 370 ft from the pumping well (PW-3), recovered during the entire GEOSCIENCE Support Services, Inc, Telra Tech/San Diego County Water Authority 94 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 durafion of the pumping test. However, at the end of the pumping test, groundwater level recovery accelerated in this well after the pumping well was tumed off (see Appendix H; Figure 43). Furthermore, when all three of the Oceanside Desalter pumping wells were lumed back on at the end of the recovery phase of the pumping test, groundwater levels in D/B2/MW1-D responded with more than six ft of drawdown (relative lo the groundwater level measured at the start of the PW-3 pumping test; see Figure 43). These data suggest lhal groundwater pumping in PW-3 was impacting the recovery rate of groundwater levels in D/B2/MW1-D and lends support for the assertion that the bedrock aquifer is in hydraulic continuity with the alluvial aquifer. Drawdown observed in D/B2/MWl-p when all three Desalter pumping wells were tumed on may be a result of pumping from Desalter PW-2, a portion of which is perforated within the bedrock aquifer (from 160 to 180 ft bgs). Aquifer zone testing in the pilot borehole for D/TW1/PW9 did not confirm the results of the PW-3 pumping test that pumping from the deep alluvial aquifer impacts groundwater levels in the bedrock aquifer. However, this may be a result of the short duration of the Zone No. 3 lest (approximately 7 hours) and not the potential for hydraulic connecfion. Groundwater levels in bedrock monitoring well D/B2/MW1-D, located approximately 50 ft from the pumping well, recovered during the entire lest (see Figure 41). On the other hand, pumping from bedrock Zone No. 1 (245-265 ft bgs) resulted in approximately 5 ft of drawdown in deep alluvial monitoring well D/B2/MW1-S (see Figure 41). The results support the PW-3 pumping test results that indicate a limited hydraulic connecfion between the deep alluvial aquifer and the bedrock aquifer. Furthermore, the higher static groundwater levels in the bedrock monitoring wells than in the alluvial monitoring wells at sites with nested monitoring wells indicates the bedrock aquifer is leaking upward into the deep alluvial aquifer. 8.3 Groundwater Quality A complete list of general geochemistry, metals, and inorganic constituents analyzed in the wells perforated within the shallow and deep alluvial aquifer, and the bedrock aquifer are presented in GEOSCIENCE Support Services. Inc. Telra Tech/San Diego County Waler Authority 95 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 Table 5, and Tables 12 through 14. Laboratory groundwater analytical reports are provided in Appendix D. 8.3.1 Shallow Alluvial Aquifer The groundwater quality of the shallow alluvial aquifer, based on water quality data from Oceanside Wells PW-4 and PW-5 and 2A/B2/MW1-S, does not show any predominant water type, although 2A/B2/MW1-S is relafively enriched in sulfate relafive to other anions (see Figure 44). The TDS of shallow alluvial groundwater is typically above 1,600 mg/L. This TDS concentrafion in groundwater is similar to dry season TDS concentrations measured in surface water within the San Luis Rey River but is slightly higher than wet season river flows (RECON, 1996). Nitrate concentrations in the shallow aquifer groundwater in the northeastem portion of the Mission Basin, which are typically between 10 and 15 mg/L (as nitrate), are similar to those of the surface waler of the river in this area (RECON, 1996) and are likely a result of agricultural runoff up-gradient of the Mission Basin. Other disfinguishing features of the shallow alluvial groundwater quality are relafively high sulfate and manganese concentrafions (see Tables 12 and 13). The only organic compound detected in the shallow alluvial groundwater was 1,2,3-Trichloropropane (1,2,3-TCP). This compound was detected al a concentration of 15 nanograms per liter (ng/L) in monitoring well 2A/B2/MW1-S. The source of the 1,2,3-TCP is not known. 8.3.2 Deep Alluvial Aquifer According to laboratory results of groundwater sampled during the Phase 2 field invesfigation program, except for Site 1, the groundwater quality of the deep alluvial aquifer does not show any predominant water type (see Figure 44), and is very similar to the groundwater quality in the GEOSCIENCE Support Services, Inc. " Tetra Tech/San Diego Couniy Water Authorily 96 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 shallow alluvial aquifer. Groundwater quality of well IC/TWl is enriched in chloride relafive to other anions. The TDS concentration of the deep alluvial groundwater is also similar lo that of the shallow alluvium, generally ranging between 1,500 and 1,880 mg/L (see Table 14; Plate 1). Unlike the shallow alluvial aquifer, the deep aquifer groundwater generally contains higher concentrations of iron, particularly in the vicinity of the Oceanside Desalter. Manganese concentrations are also relatively high in this aquifer. The only organic compound detected in the deep alluvial groundwater was 1,2,3-TCP. This compound was detected at a concentration of 230 ng/L in the sample collected from Zone No. 3 in the pilot borehole for D/TW1/PW9. The source ofthe 1,2,3-TCP is not known. 8.3.3 Sedimentary Bedrock Aquifer The groundwater quality of the bedrock aquifer is enriched in sodium or potassium relafive to the other cations (see Figure 45), which is different than the waler quality of the groundwater sampled from the alluvial aquifer. The bedrock aquifer water quality is more characlerisfic of seawater than the alluvial aquifer water quality. However, TDS concentrations in the bedrock aquifer groundwater are generally lower than the alluvial aquifer groundwater and, unlike the alluvial aquifers, the TDS concentrafion of the bedrock aquifer groundwater is highly variable, ranging between 480 and 1,400 mg/L (see Table 14; Plate 1). Other unique characterisfics of bedrock aquifer waler quality are a relafively low hardness (less than 160 mg/L), high concentrations of aluminum, iron, and relatively low concentrafions of manganese. 8.4 Volume of Groundwater in Storage The volume of groundwater in storage within the alluvial aquifers (shallow and deep) in the Mission Basin was esfimated using the following procedure: GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 97 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Aquifer Storage Capacity = (Volume of Saturated Sediments) * (Effecfive Porosity"') The volume of saturated alluvial sediments was esfimated from the area of the Mission Basin, a groundwater elevation contour map generated from October 2003 groundwater levels (see Figure 8), and a contour map ofthe top of sedimentary bedrock (see Figure 7). Effective porosity was esfimated from the types of sediments encountered during the Phase 2 drilling programs and published data (Johnson, 1967). The following procedure was followed lo esfimate the groundwater storage of the Mission Basin: • The boundary of the Mission Basin was digifized based on land surface elevation from United States Geological Survey (USGS) digital elevation models ofthe area (10-meler resolufion). • The bedrock elevation map is based on detailed lithologic logs and geophysical logs of Phase 2 boreholes that intercepted the sedimentary bedrock and water well driller's logs from the Califomia Department of Water Resources (DWR). • GIS was used lo subtract the groundwater elevation surface from the bedrock elevation surface across a 10-meler by 10-meler grid. This resulted in an estimate of the volume of saturated sediments in the basin. • An average effective porosity was calculated from available lithologic logs. Each lithologic interval was assigned an effective porosity based on published values (Johnson, 1967). The volume of saturated sediments was then mulfiplied by the effective porosity to obtain the aquifer storage capacity estimate. Also called specific yield or "drainable porosity". GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Water Authority 98 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 The known saturated alluvial thickness within the Mission Basin ranges from zero fl at the bedrock outcrops to approximately 200 fl at the westem end of the basin (Site 1). Based on an assumed effecfive porosity of aquifer sediments of 10 percent and groundwater surface contours based on data collected in October 2003, the total volume of groundwater in storage was estimated to be approximately 54,000 acre-ft (see Figure 46). Using the same methodology as described above, the available groundwater storage capacity in the unsaturated zone between the land surface and the groundwater surface (vadose zone) of the Mission Basin was also esfimated (see Figure 47). The average depth to groundwater in the Mission Basin is approximately 19 ft. Based on this data and an estimated effective porosity of 10 percent, the current total storage capacity of the unsaturated zone is approximately 9,000 acre-ft. This storage capacity could be increased from lowering of groundwater levels as would occur during increased periods of groundwater pumping in a conjuncfive use program. However, potential for liquefaction from high groundwater levels and potenfial impact to riparian habitats along the San Luis Rey River from lowered groundwater levels should be taken into consideration for future conjunctive use acfivities in the Mission Basin (see Secfion 10.2 Potential Geohydrologic Constraints to Conjuncfive Use in the Mission Basin). The aquifer storage capacity of the sedimentary bedrock aquifer underlying the Mission Basin cannot be esfimated based on available data. Based on the regional geology of the area, this aquifer system likely extends outside the limits of the alluvial aquifer. Furthermore, the geohydrologic properties of this aquifer have nol been fully characterized to date. However, it can be assumed that additional groundwater storage in the Mission Basin is available from the bedrock aquifer. GEOSCIENCE Support Services, Inc. Telra Tech/San Diego Couniy Water Authority 99 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 9.0 RESULTS OF FIELD INVESTIGATION PROGRAM - BONSALL BASIN 9.1 Lithology 9.1.1 Alluvium Unconsolidated sediments encountered during the drilling of exploratory borehole 26/27/Bl consisted primarily of sand and gravel (see Appendix B). Boulders of granific rock were encountered below a depth of 90 ft lo the base of the alluvium. The sands and gravels are poorly sorted with low percentages of fines. The origin of the alluvium is primarily granific (quartz, feldspar and mica), presumably weathered from the Peninsular Ranges to the east of the Bonsall Basin. 9.1.2 Bedrock Granitic bedrock was encountered in the borehole at Site 26/27 at a depth of approximately 116 ft bgs (see Appendix B). The bedrock is similar to the tonalite encountered al Sites 13 and 13A in the eastern portion of the Mission Basin, and is likely the Bonsall Tonalite described in Izbicki (1985b). 9.2 Alluvial Aquifer System Groundwater levels measured in well 26/27/MWl was reported to be 12.55 ft bgs (228.05 ft amsl) in both the shallow and deep casings (see Table 3). Since the casings are perforated at different intervals wilhin the alluvial aquifer, this data indicates lhal the alluvial aquifer at Site 26/27 is unconfined. However, data limited to 'Site 26/27 does nol represent aquifer conditions in the remaining areas of the basin. Likewise, groundwater flow direction in GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Waler Authority 100 Geohydrologic Investigation - Lower San Luis Rey River Valley 3]-Aug-04 the alluvial aquifer cannot be determined from one data poinl. Consequently, the flow direction is presumably the same as the San Luis Rey River. The groundwater quality of the alluvial aquifer, based on water quality data fi^om well 26/27/MWl-S and -D, does not show any predominant waler lype (see Figure 48). The TDS of the alluvial groundwater from this well was reported as 1,500 mg/L in the shallow casing and 1,300 mg/L in the deep casing. This TDS concentrafion in groundwater is similar to TDS concentrations previously reported by Izbicki (1985b). Nitrate concentrations in the alluvial aquifer groundwater at Site 26/27 were between 5.6 and 6.1 mg/L (as nitrate), and are likely a result of agricultural runoff up-gradient of the Bonsall Basin. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 101 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 10.0 CONCLUSIONS AND RECOMMENDATIONS 10.1 Mission Basin 10.1.1 General Conclusions In terms of groundwater producfion, the most favorable locations within the Mission Basin for high capacity production wells are those in the southem portions of the basin where the alluvial sediments are characterized by high permeability sand and gravel and the thickness of these sediments is the greatest. Pumping wells in these areas could produce as much as 2,000 gpm of instantaneous flow. Furthermore, pumping wells in the southem portion of the basin would have the least impact on surface water flow wilhin the San Luis Rey River because they are furthest from the river. The most favorable locafions for future producfion wells include the areas al or in the vicinity of investigafion Sites 32, lOA and the Oceanside Desalter site. Based on existing data, the sedimentary bedrock aquifer does not appear to be a significant source of groundwater to future production wells. However, the existing data is specific to one area of the basin and, given the relafively permeable sediments observed in cores in other areas, further pumping tests within the bedrock aquifer in other porfions of the basin are warranted. Ardficial recharge via surface spreading basins is likely feasible in many areas of the Mission Groundwater Basin as long as current groundwater levels can be lowered to create the necessary subsurface storage space. The high percentage of relafively permeable alluvial sediments in the southem portions of the basin is conducive to the downward percolafion of surface water. Furthermore, no laterally extensive impermeable silt and/or clay layers were idenfified that would inhibit percolafion of surface water. The most favorable sites for artificial recharge using surface spreading basins are Sites 2A, lOA, 13A and the desaller site. However, feasibility of artificial recharge using surface spreading basins should be confirmed through a pilot-tesfing program (see Section 10). GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 102 Geohydrologic Investigation - Lower San Luis Rey River Valley . 31-Aug-04 Artificial recharge via injecfion wells may be feasible within the alluvial aquifers in some portions of the westem part of the Mission Basin. However, further testing is required lo verify this conclusion. Condifions that appear to be most favorable for injection wells occur at Sites 1, 7A, 9A, 11, 32 and the Desalter site. Based on existing data, the potential for artificial recharge of the bedrock aquifer system via injecfion wells appears to be low. Pumping test data and laboratory analysis of samples suggest that the permeability of the sedimentary bedrock is relatively, low and would not accept large volumes of water. However, given the relafive lack of data regarding the lateral variafion in bedrock permeability, further testing in other areas of the basin would be beneficial lo verify this conclusion. 10.1.2 Site 1 10.1.2.1 Site 1 Conclusions Based on the data collected during the Phase 2 field investigations al Site 1 (the proposed seawater injection barrier site), the following conclusions have been reached: • Seawater intmsion does not appear lo currenfiy be an issue within the basin. Although there is evidence that seawater intmsion has occurred in the Mission Basin during the last 100 years (DWR, 1960), the groundwater flow direction within the basin has been toward the ocean at least since the early 1970s and TDS and chloride concentrations are similar to those detected in monitoring wells inland from this site. • The bedrock strafigraphy and geologic structure at Site 1 are favorable for the construction of a seawater barrier al this site. Site 1 is located within a narrow gorge, the walls of which are composed of relafively impermeable San Onofre Breccia bedrock. This impermeable bedrock also underlies the alluvium at Site 1. Thus, movement of GEOSCIENCE Support Services. Inc. Telra Tech/San Diego Couniy Water Authorily 103 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 groundwater through Site 1 can only occur through the unconsolidated alluvium. These localized conditions are favorable for some form, of hydraulic barrier to seawater intmsion at this site. • While the relatively permeable nature of the alluvial sediments beneath Site 1 are ' conducive to the injection of waler into the formation, the lack of a competent silt/clay layer in the upper 100 ft of the alluvium is not favorable for injecfion. Without a natural "cap," injected water will not migrate into the formafion but, instead, will tend to migrate upward lo the ground surface in the immediate vicinity of the injecfion well. A silty sand layer has been logged in one borehole at Site 1 between approximately 30 and 50 ft bgs (see Plate 1). However, the competence of this layer lo provide a strafigraphic barrier would have to be invesfigated further. • Using the transmissivity obtained from the IC/TWl pumping test, and assuming 10 ft of allowable drawdown, a production well at this site could produce as much as 260 gpm. As a general mle, an injecfion well may be expected to inject at half of the production rate (i.e. approximately 130 gpm). As an altemative to using injection wells for creafing a hydraulic barrier at Site 1, surface recharge ponds located along the river could be used for the same purpose. Given the types of sediments in the area, recharge ponds may have a greater potential for success in creating the barrier with less maintenance. • Large-diameter verfical shafts, as have been described by Bouwer (2002), would nol be "as favorable as recharge basins at Site 1 because they tend to clog over time and, because they are filled with gravel, cannot be rehabilitated. In summary, the natural geologic conditions at Site 1 are very favorable for a seawater intrusion barrier in this area. In addifion, it is likely that a hydraulic barrier can be achieved. The exact method of achieving the hydraulic barrier (i.e. injecfion wells or recharge basins) requires further testing. Recommendations for further testing at Site 1 are provided in the following section. GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Water Authority 104 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 10.1.2.2 Site 1 Recommendations Considering the three altemafive methods of arfificial recharge discussed for this site (injecfion wells, surface spreading basins, and verfical shafts) in the contexl of the exisfing Phase 2 data, the altemative with the greatest probability for success to create a seawater intrusion barrier is surface spreading basins. These basins could be constructed in the area southwest of the existing test well where the river channel bends to the northem portion of the gorge, creafing an area of available land. Surface spreading within a linear series of rectangular spreading basins oriented perpendicular to the San Luis Rey River would have the greatest probability of creafing and maintaining a localized groundwater mound capable of prevenfing inland seawater migrafion, should inland groundwater levels be lowered to a point where seawater intrusion was a concem. As a further test of the feasibility of artificial recharge al Site 1 using surface spreading basins, it is recommended to conduct a small-scale pilot recharge lest in the area. Such a test would involve construcfing a small-scale basin (approximately one-tenth acre) in close proximity (approximately 500 ft) to the existing test well. A shallow monitoring well would be installed in the middle of the basin to monitor groundwater levels during the test. Pumping from the existing test well could be used to supply water for the test. In this way, aquifer parameters based on groundwater drawdown and mounding could be evaluated both from the pumping test and the recharge test, respectively. The drawdown cone of depression and the groundwater mound may coalesce but the general quesfion of the feasibility of artificial recharge using spreading basins could be answered. Furthermore, because there would be no net reducfion in groundwater from the aquifer, the environmental impacts could be minimized. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 105 Geohydrologic Investigation - Lowcr San Luis Rey River Valley 31 'Aug-04 10.1.3 Site2A 10.1.3.1 Site 2A Conclusions Data collected during the Phase 2 field investigations at Site 2A to evaluate artificial recharge and/or groundwater extraction potential have resulted in the following conclusions: • The stratigraphy and aquifer characteristics of the shallow alluvial aquifer at Site 2A appear to be conducive to artificial recharge via surface spreading basins. Although some less permeable silty sand layers exist in the upper 50 fl, the relafively high percentage of sand suggests that they would allow for vertical percolafion of surface water. Although the depth lo groundwater beneath Site 2A is currently too shallow (approximately 14 ft bgs) lo allow for the recharge of surface water via surface recharge basins or injection wells, future lowering of groundwater levels as a result of increased groundwater production within the Mission Basin may result in a groundwater level low enough to store water in the subsurface. • The depth at which groundwater recharge becomes feasible depends primarily on the permeability of the sediments. Higher permeability sediments will result in shallow groundwater mounds during recharge and will allow for the recharge of more water than lower permeability sediments. Assuming the shallow alluvial sediments beneath Site 2A have a similar hydraulic conducfivity to the sediments in the alluvial aquifer at the Oceanside Desalter Site (as esfimated from pumping test data), an addifional 5 to 10 ft of drawdown should be adequate to accommodate artificial recharge via surface spreading basins. However, these conclusions should be verified at Site 2A through a controlled pilot recharge test at the site. Artificial recharge by injection into the shallow alluvial aquifer would be limited by the relative lack of a confining layer in the upper 50 ft of sedimenls- and the lack of a thick aquifer between 50 fl and the bedrock surface. The silty sand layer that exists between GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 106 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 approximately 30 and 40 ft bgs (see Plate 1) may provide enough of a strafigraphic barrier to allow for the injecfion of water into the shallow alluvial aquifers below it (although this should be field tested). Groundwater producfion from the shallow alluvial aquifer would be limited. The relafively thin aquifer available below 50 ft (the required depth for a surface seal) would not likely yield significant quanfifies of water lo a well(s). Groundwater production from the bedrock aquifer would likely be limited. The low hydraulic conductivity of the aquifer sediments (as indicated by laboratory analysis of soil samples [see Table 4] and pumping tests at the Oceanside Desaller Site) would nol be conducive to yielding large quantifies of groundwater to wells. Bedrock layers beneath Site 2A with the greatest potenfial for groundwater producfion are the sandstone layers between 130 and 170 ft bgs and 185 to 260 ft bgs. Data from the Desalter Site test well suggest production rates less than 50 gpm could reasonably be expected although further testing specific to Site 2A is necessary lo verify this. • The potential for artificial recharge by injection into the bedrock aquifer does nol appear to be promising. The low hydraulic conducfivity suggested by soil permeability tesfing in 2A/B2 (l.lOE-05 to 5.00E-O5 cm/sec) and low groundwater discharge rates during aquifer zone tesfing in the bedrock at the Desalter Site suggest that the capacity of this aquifer lo accept large amounts of recharge waler is very limited. Injecfion rates would likely be as litfie as one half of the esfimated production rate (less than 25 gpm). In summary, the most favorable alternative for Site 2A is artificial recharge using surface spreading basins. ]^ GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Waler Authority 107 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 10.1.3.2 Site 2A Recommendations To further evaluate the potential for artificial recharge at Site 2A, il is recommended lo conduct a small-scale pilot recharge lest. The existing storm water retenfion basin al this site could be used for the pilot basin although, given the relatively large size of the exisfing basin, a smaller "subbasin" may be necessary for tesfing purposes. The pilot basin could be centered on the existing monitoring well although additional monitoring wells would be recommended lo assess groundwater mounding and migration characterisfics. Ideally, the test would be conducted for several months and the source of water for the test would be the same as would be used for the large-scale recharge program. A pilot-scale surface recharge test at Site 2A would help assess the following: The ability for surface water to migrate lo the groundwater, • The surface recharge rate, which will determine the amount of water that can be recharged at this site. The groundwater mounding characterisfics, which will also be used to assess the amount of water that can be stored beneath the site, The migrafion characteristics of the stored water, • Clogging characteristics of the recharge basins, and • Potential changes in groundwater chemistry resulting from migrafion through the unsaturated zone and mixing with native groundwater. The details of a pilot recharge test at Site 2A should be prepared in the form of a pilot test work plan that describes the recharge basins, monitoring facilifies, and data collection procedures (types and frequency of measurement). GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Water Authorily 108 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 10.1.4 Site2B Data collected during the Phase 2 field invesfigation at Site 2B to evaluate artificial recharge and/or groundwater extracfion potenfial have resulted in the following conclusions: The strafigraphy and aquifer characteristics of the shallow alluvial aquifer at Site 2B appear to be conducive to artificial recharge via surface spreading basins. However, the site is nol large enough lo support artificial recharge basins. Artificial recharge by injecfion into the shallow alluvial aquifer would be limited by the relative lack of a confining layer in the upper 50 fl of sediments and the limited space at the site for an injection well. • Groundwater production from the shallow alluvial aquifer is not recommended. The relatively thin aquifer available below 50 ft (the required depth for a surface seal) would not likely yield significant quantifies of water to a well(s). • The potential for artificial recharge by injection into the bedrock aquifer beneath Site 2B does not appear to be promising. The low hydraulic conductivity suggested by testing of the bedrock at other sites in the area suggests that the capacity of this aquifer to accept large amounts of recharge waler is limited. As discussed previously, injecfion rales would likely be as little as one half of the estimated production rale (less than 25 gpm). Groundwater production from the bedrock aquifer would likely be limited. The low hydraulic conducfivity of the aquifer sediments would not be conducive to yielding large quantities of groundwater to wells. As discussed previously, production rates from the bedrock aquifer would likely be less than 50 gpm. The primary constraint for any groundwater recharge/extracfion facility at Site 2B is the linriiled available space at the site. In considerafion of this, artificial recharge and groundwater producfion at other sites should be considered before implementing such programs at Site 2B. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 109 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 10.1.5 Site3B 10.1.5.1 Site 3B Conclusions Data collected during the Phase 2 field invesfigations at Site 3B lo evaluate arfificial recharge and/or groundwater extraction potenfial have resulted in the following conclusions: • The stratigraphy and aquifer characteristics of the shallow alluvial aquifer at Site 3B may be conducive to artificial recharge via surface spreading basins. Sediments in the upper 20 to 50 ft bgs consist predominantly of relafively permeable sand. Sediments below 50 ft bgs are predominantly less permeable silt and clay. A controlled artificial recharge pilot lest should be performed at Site 3B to assess the permeability and mounding characterisfics ofthe sediments in the upper 50 ft bgs. • Arfificial recharge by injecfion into the shallow alluvial aquifer is not a viable option due to the fine-grained nature of the alluvial aquifer sediments below 50 ft bgs (the minimum required depth for a surface seal) at this site. • Groundwater production from the shallow alluvial aquifer is also not a viable opfion due to the fine-grained nature of the alluvial aquifer sediments below 50 fl bgs. • The potential for artificial recharge by injecfion into the bedrock aquifer beneath Site 3B does not appear to be promising. The low hydraulic conductivity suggested by testing of the bedrock al other sites in the area suggests that the capacity of this aquifer to accept large amounts of recharge water is limited. As discussed previously, injecfion rates would likely be as little as one half of the esfimated producfion rale (less than 25 gpm). • Groundwater producfion from the bedrock aquifer would likely be limited. The low hydraulic conducfivity of the aquifer sediments would not be conducive to yielding large quantities of groundwater to wells. As discussed previously, production rates from the bedrock aquifer would likely be less than 50 gpm. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 110 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 In summary, the most promising conjunctive use altemative for Site 3B is alluvial aquifer recharge using surface spreading basins. However, the feasibility of this altemative should be tested further as described in the following secfion. 10.1.5.2 Site 3B Recommendations To further evaluate the potential for artificial recharge at Site 3B, il is recommended to conduct a small-scale pilot recharge test. This lest would be conducted using a small-scale (i.e. 0.25-acre) spreading basin. The pilot basin could be centered on the exisfing monitoring well although additional monitoring wells would be recommended to assess groundwater mounding and migration characteristics. Ideally, the test would be conducted for several months and the source of waler for the test would be the same as would be used for the large-scale recharge program. The objectives of the pilot recharge test are the same as those outlined for Site 2A in Section 10.1.3.2. The details of a pilot recharge test at Site 3B should be prepared in the form of a pilot lest work plan that describes the recharge basins, monitoring facilifies, and data collecfion procedures (types and frequency of measurement). 10.1.6 Site3C 10.1.6.1 Site 3C Conclusions Data collected during the Phase 2 field investigation at Site 3C lo evaluate artificial recharge and/or groundwater extraction potential have resulted in the following conclusions: GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Waier Authority 111 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 • The strafigraphy and aquifer characteristics of the shallow alluvial aquifer at Site 3C are not conducive to artificial recharge via surface spreading basins. The upper approximately 20 ft of alluvial sediments is primarily silt, which would not be conducive lo the verfical percolation of surface waler. • Artificial recharge by injecfion into the shallow alluvial aquifer may be a viable option provided the sill layer in the upper 20 ft of sediments is competent to allow for the injecfion of water and the relafively thin aquifer between 50 ft and 80 ft bgs is permeable enough to accept water. Given the 30 ft aquifer thickness and assuming an aquifer permeability similar lo that esfimated from pumping tests in wells at the Oceanside Desalter site, an injecfion well at this site could be expected to inject at a rate of approximately 50 to 150 gpm. • Groundwater producfion from the shallow alluvial aquifer is nol recommended. The relatively thin aquifer available below 50 ft (the required depth for a surface seal) would not likely yield significant quanfifies of waler lo a well(s). • The potential for artificial recharge by injection into the bedrock aquifer beneath Site 3B does not appear to be promising. The low hydraulic conductivity suggested by testing of the bedrock at olher sites in the area suggests that the capacity of this aquifer to accept large amounts of recharge water is limited. As discussed previously, injection rates would likely be as little as one half of the estimated producfion rate (less than 25 gpm). • Groundwater production from the bedrock aquifer would likely be hmited. The low hydraulic conductivity of the aquifer sediments would not be conducive to yielding large quantities of groundwater to wells. As discussed previously, production rates from the bedrock aquifer would likely be less than 50 gpm. In summary, the most promising altemative for Site 3C is alluvial aquifer recharge using injecfion wells. Recommendations for further testing are provided in the following secfion. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 112 Geohydrologic Invesligaiion - Lower San Luis Rey River Valley 31-Aug-04 10.1.6.2 Site 3C Recommendations The feasibility of aquifer recharge using injecfion wells at Site 3C should be further evaluated through the drilling, construction and testing of an injection well at the site. The well should be drilled and tested using the same methods and procedures as employed for the Oceanside , Desalter Test Well (D/TW1/PW9). This would include, al a minimum, the collection of soil samples during the drilling of the pilot borehole, geophysical logging, aquifer zone testing, design and construction of an injecfion well (well depth and diameter to be determined based on examination of the pilot borehole logs arid zone tesfing results), and both pumping and injection testing. As part of the drilling and tesfing at Site 3C, it is recommended to extend the pilot borehole for the injecfion well into the sedimentary bedrock aquifer, to enable aquifer zone testing within this formation. This would provide addifional informafion regarding the potential yield of this aquifer. If promising, the injection well could also be extended into this aquifer. Another important aspect of the injection testing would be water quality analysis. If possible, water used for the injection tesfing should be the water that would ulfimately be used in a large-scale project to assess changes in water chemistry resulting from the injection process as well as mixing with the native groundwater. Details of the injection well drilling, construction and testing should be outlined in detailed technical specificafions lo be prepared prior lo drilling. GEOSCIENCE Support Services, Inc, Telra Tech/San Diego Couniy Waler Authority 113 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 10.1.7 Site7A 10.1.7.1 Site 7A Conclusions Data collected during the Phase 2 field investigafion at Site 7A to evaluate artificial recharge and/or groundwater extracfion potenfial have resulted in the following conclusions: • The stratigraphy and aquifer characteristics of the shallow alluvial aquifer at Site 7A appear to be conducive lo artificial recharge via surface spreading basins. Although some less permeable silty sand layers exist in the upper 50 ft, the relatively high percentage of sand suggests that they would allow for verfical percolafion of surface waler. However, the relafively limited space would not be conducive to surface recharge basins. • The groundwater depth beneath Site 7A (approximately 20 ft bgs) may currently be adequate to allow for the recharge of surface water via surface recharge basins. Assuming the shallow alluvial sediments beneath Site 7A have a similar hydraulic conducfivity to the sediments in the alluvial aquifer at the Oceanside Desalter Site (as estimated from pumping test data), 20 ft of unsaturated sediments should be adequate lo accommodate artificial recharge via surface spreading basins. However, these conclusions should be verified at Site 7A through further tesfing. • Artificial recharge by injection into the shallow alluvial aquifer would be limited by the relafive lack of a confining layer in the upper 50 ft of sediments. Although the silty sand layers that exist in the upper 50 ft bgs (see Plate 1) may provide enough of a strafigraphic barrier to allow for the injecfion of water into the shallow alluvial aquifers below il, this should be field tested. GEOSCIENCE Support Services, Inc.' Telra Tech/San Diego County Water Authority 114 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 • Groundwater production from the shallow alluvial aquifer at Site 7A is a viable option. The alluvial aquifer system is of adequate thickness (approximately 100 ft of unconsolidated, coarse-grained sediments) and permeability to provide suitable yield to producfion wells. Preliminarily, a well al this site would be constmcted similarly to the Desalter Test Well (D/TW1/PW9) with perforafions between approximately 70 ft and 150 ft bgs. Such a well could be expected to have a production capacity as high as City of Oceanside Wells 4 or 5 (approximately 1,000 gpm), however this should be verified through further test drilling. • It is not known, based on available data, whether groundwater producfion from or artificial recharge into the bedrock aquifer at Site 7A is feasible. Although the sandstone aquifer was encountered during the drilling of monitoring well 7A/B1/MW1, the thickness and permeability of the sedimentary formafion in this area is unknown given the proximity of the site to other sites where granific bedrock was encountered (see Plate 1). In summary, although the geohydrological condifions at Site 7A appear to be conducive to artificial recharge using surface spreading basins, the use of such basins may not be practical due lo limited available space at the site. Groundwater recharge in the alluvial aquifer using injecfion wells may be feasible at this site but further tesfing is necessary to verify this. Site 7A may also be a viable site for a groundwater producfion well. The feasibility of recharge and extracfion from the bedrock aquifer beneath Site 7A is not known based on available data. 10.1.7.2 Site 7A Recommendations Given the limited space al Site 7A, prioritization of further testing at the site should be focused on groundwater producfion/injection wells. A lest well at this site would be constructed and tested as described for Site 3C (see Section 10.1.6.2). It is also recommended to drill the pilot GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 115 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 borehole into the sedimentary bedrock aquifer to enable aquifer zone testing, and possible completion of the well in this unit. As with the well at Site 3B, both pumping and injection tests would be conducted on the well. Details of the injection well drilling, construction and testing should be outlined in detailed technical specifications to be prepared prior lo drilling. 10.1.8 Site 9A 10.1.8.1 Site 9A Conclusions Data collected during the Phase 2 field invesfigafion at Site 9A to evaluate artificial recharge and/or groundwater extracfion potenfial have resulted in the following conclusions; • The strafigraphy and aquifer characterisfics of the shallow alluvial aquifer at Site 9A appear to be moderately favorable for artificial recharge via surface spreading basins. Less permeable silty sand and clay layers exist in the upper 50 to 60 ft of sediments and additional exploratory boreholes are recommended prior to constmcfing recharge facilities. " Although groundwater levels beneath Site 9A are currenfiy loo shallow to allow for the recharge of surface water via surface recharge basins, future lowering of groundwater levels as a result of increased groundwater producfion within the Mission Basin may result in a groundwater level low enough to store water in the subsurface. • As discussed for olher potential arfificial recharge sites, the depth at which groundwater recharge becomes feasible depends primarily on the permeability of the sediments, which should be verified through further tesfing at the site. GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Water Authority 116 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 • Artificial recharge by injection into the shallow alluvial aquifer appears to be favorable at Site 9A. The relatively high percentage of fine-grained sediments in the upper 50 to 60 ft may be adequate to allow for the injecfion of water although further tesfing is necessary to verify this. • Groundwater production from the shallow alluvial aquifer at Site 9A is a moderately favorable opfion. The alluvial aquifer system is of adequate thickness (approximately ,64 ft of unconsolidated, coarse-grained sediments) and permeability to provide suitable yield to producfion wells. Preliminarily, a well at this site would be constructed similarly to the Desalter Test Well (D/TW1/PW9) with perforations between approximately 70 ft and 115 ft bgs. Given the relatively thin aquifer, such a well would be expected lo have a production capacity between 500 and 1,000 gpm, however this should be verified through further lest drilling. • It is not known, based on available data, whether groundwater production from or arfificial recharge into the bedrock aquifer at Site 9A is feasible. The sandstone aquifer was not encountered during the drilling of Borehole 9A/B1 and the thickness and permeability of the sedimentary formation in this area is unknown (see Plate 1). In summary. Site 9A is promising for artificial recharge of the alluvial aquifer using surface spreading basins or injection wells and may be a viable alluvial aquifer producfion well site. 10.1.8.2 Site 9A Recommendations It is recommended that further tesfing at Site 9A be inifially focused on test drilling and producfion/injecfion well constmction. In so doing, the nature and lateral extent of the silly sediments in the upper 50 to 60 ft of sediments can be more fully evaluated. Two lo three additional test boreholes located both to the west and east of 9A/B1 would provide a better understanding of the lateral extent of fine-grained sediments in the upper 50 to 60 ft bgs. One of GEOSCIENCE Support Services, Inc. Telra Tech/San Diego Couniy Water Authority 117 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 the test boreholes should be drilled for the purpose of constructing a test well. It is recommended to drill the pilot borehole for the test well into the sedimentary bedrock aquifer lo enable aquifer zone testing, and possible completion of the well in this unit. The test well could be constructed to enable both producfion and injecfion tesfing. Details of the production/injecfion well drilling, construction and tesfing should be oufiined in detailed technical specificafions prepared prior to drilling. In the event that the additional drilling and tesfing show that Site 9A is a viable candidate for arfificial recharge using surface spreading basins, a pilot recharge test using surface spreading basins may be recommended. The pilot test would include the constmcfion of a small-scale (0.5-to 1-acre) rectangular spreading basin constructed of earthen berms. Monitoring wells (both wilhin and surrounding the spreading basin) would be necessary to enable the collecfion of groundwater level and quality data before, during and after the lest. Ideally, the test would be conducted for several months and the source of water for the lest would be the same as would be used for the large-scale recharge program. A pilot-scale surface recharge test at Site 9A would help assess the following: The ability for surface water to migrate to the groundwater. The surface recharge rale, which will determine the amount of waler that can be recharged at this site, • The groundwater mounding characterisfics, which will also be used to assess the amount of water that can be stored beneath the site, • The migrafion characteristics of the stored water. Clogging characteristics of the recharge basins, and Potenfial changes in groundwater chemistry resulting from migration through the unsaturated zone and mixing with nafive groundwater. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 118 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 The details of a pilot recharge test at Site 9A should be prepared in the form of a pilot test work plan that describes the recharge basins, monitoring facilities, and data collection procedures (types and frequency of measurement). 10.1.9 Site lOA 10.1.9.1 Site lOA Conclusions Data collected during the Phase 2 field invesfigation al Site lOA to evaluate artificial recharge and/or groundwater extracfion potenfial have resulted in the following conclusions: • Based on available data, the stratigraphy and aquifer characteristics of the alluvial aquifer al Site lOA are marginally conducive to artificial recharge via surface spreading basins although additional data are necessary lo verify this. The logged portion of the upper approximately 50 ft of sediments contains a high percentage of silt and clay. However, the upper approximately 12 ft of sediments are arfificial fill associated with the berms around the exisfing storm water retenfion basin and the interval from approximately 20 to 40 ft bgs was not logged. • As discussed for other poteniial artificial recharge sites, the static groundwater level at which groundwater recharge becomes feasible depends primarily on the permeability of the sediments, which should be verified through further testing al the site. Higher permeability sediments will require less drawdown to accommodate additional waler. Confingent on verifying the stratigraphy beneath the site, artificial recharge by injection into the shallow alluvial aquifer appears lo be favorable at Site lOA. The relatively high percentage of fine-grained sediments in the upper 50 ft, if consistent throughout the interval, would be adequate to allow for the injection of water. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Aulhorily 119 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 • Groundwater production from the shallow alluvial aquifer at Site lOA is very favorable. The alluvial aquifer system is of adequate thickness (approximately 94 ft of unconsolidated, coarse-grained sediments) and pemieabiJity to provide suitable yield lo production wells. Preliminarily, a well at this site would be constructed similarly to the Desalter Test Well (D/TW1/PW9) with perforafions between approximately 70 ft and .155 ft bgs. Assuming that the permeability of the aquifer sediments is as high as that estimated from pumping tests on wells in the vicinity of the Oceanside Desalter, a well al Site lOA could produce more than 1,000 gpm. • It is not known, based on available data, whether groundwater producfion from or artificial recharge into the bedrock aquifer al Site lOA is feasible. Although the sandstone aquifer was encountered during the drilling of monitoring well 10/VBl/MWl, the thickness and permeability of the sedimentary formafion in this area has nol been investigated. In summary, the most promising altemative for Site lOA is groundwater producfion from the alluvial aquifer. Alluvial aquifer recharge using either surface spreading basins or injecfion wells may also be viable alternatives but more tesfing is required to confirm this. Recommendations for further testing are provided in the following secfion. 10.1.9.2 Site lOA Recommendations To further evaluate the production potenfial ofthe alluvial aquifer al Site lOA, il is recommended to drill and constmct a test well at this site. Soil samples collected during the drilling of the pilot borehole for the well could be used lo assess the nature of sediments in the upper 50 ft bgs. Furthermore isolated aquifer zone testing is recommended to assess waler quality differences with depth and aquifer production potential. In the event that the shallow sediments beneath the site are predominantly fine-grained (i.e. silt and clay), the well could be designed lo function as GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 120 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 both a production well and injecfion well. Pumping and, if applicable, injecfion tests should be conducted upon completion of well development. Details of the producfion/injecfion well drilling, constmction and tesfing should be outlined in detailed technical specifications prepared prior lo drilling. In the event thai test drilling at Site lOA indicates that the site is a viable candidate for artificial recharge using surface spreading basins, it is recommended lo conduct a sub-scale pilot recharge test. The existing storm water retenfion basin at this site could be used for the pilot basin although, given the relatively large size of the existing basin, a smaller "subbasin" may be necessary for testing purposes. In addition to the existing monitoring well al the site, three to four additional monitoring wells would be recommended within and surrounding the basin lo assess groundwater mounding and migrafion characteristics. Ideally, the lest would be conducted for several months and the source of water for the lest would be the same as would be used for the large-scale recharge program. The details of a pilot recharge test at Site lOA should be prepared in the form of a pilot lest work plan that describes the recharge basins, monitoring facilifies, and data collection procedures (types and frequency of measurement). lO.LlO Site 11 10.1.10.1 Site 11 Conclusions Data collected during the Phase 2 field investigation at Site 11 lo evaluate arfificial recharge and/or groundwater extraction potential have resulted in the following conclusions: GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authorily 121 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 • The stratigraphy and aquifer characteristics of the shallow alluvial aquifer al Site 11 are nol conducive to artificial recharge via surface spreading basins. The upper approximately 45 ft of alluvial sediments is primarily silt and clay (see Appendix B), which would not be conducive lo the vertical percolation of surface waler. • Artificial recharge by injection into the shallow alluvial aquifer may be a viable opfion provided the silt/clay layers in the upper 45 fl of sediments are competent to allow for the injecfion of water and the groundwater level (which is not known) is deep enough or can be lowered to allow for the storage of additional water. • The relatively thin alluvial aquifer sediments below 50 ft at Site 11 suggest the shallow alluvial aquifer has limited groundwater producfion potenfial. However, the coarse-grained nature of some layers up to 20 fl in thickness warrants further testing to verify the producfion potential of this aquifer. Il is not known, based on available data, whether groundwater production from or artificial recharge into the bedrock aquifer at Site 11 is feasible. Although the sandstone aquifer was encountered during the drilling of boring 11/Bl, the geohydrologic properties of the sedimentary formation in this area have not been investigated. Given the available data, the most promising conjunctive use altemafive for Site 11 is alluvial aquifer recharge using injection wells. Furthermore, it is recommended to further evaluate groundwater producfion from the alluvial aquifer. The feasibility of recharge and extracfion from the bedrock aquifer beneath Site 11 is not known based on available data but could be invesfigated as described in the following section. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 122 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 10.1.10.2 Site 11 Recommendations The feasibility of aquifer recharge and groundwater producfion using wells at Site 11 should be further evaluated through the drilling, construcfion and tesfing of a production/injecfion lest well at the site. The well should be drilled and tested using the same methods and procedures as employed for the Oceanside Desalter Test Well (D/TW1/PW9). This would include, at a minimum, the collecfion of soil samples during the drilling of die pilot borehole, geophysical logging, aquifer zone tesfing, design and construction of a producfion/injecfion well (well depth and diameter to be determined based on examination of the pilot borehole logs and zone testing results), and both pumping and injection tesfing. As part of the drilling and testing al Site 11, it is recommended to extend the pilot borehole for the injection well into the sedimentary bedrock aquifer, to enable aquifer zone testing wilhin this formafion. This would provide addifional information regarding the potenfial yield of this aquifer. If promising, the injection well could also be extended into this aquifer. Another important aspect of the injection tesfing would be water quality analysis. If possible, water used for the injection tesfing should be the water that would ulfimately be used in a large-scale project to assess changes in waler chemistry resulfing from the injecfion process as well as mixing with the native groundwater. Details of the injecfion well drilling, construcfion and testing should be oufiined in detailed technical specifications prepared prior to drilling. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 123 Geohydrologic Investigation - Lower San Luis Rey River Valley • 31-Aug-04 10.1.11 SitellC 10.1.11.1 Site lie Conclusions Data collected during the Phase 2 field invesfigafions at Site 1 IC to evaluate artificial recharge and/or groundwater extracfion potential have resulted in the following conclusions: • The strafigraphy and aquifer characteristics of the shallow alluvial aquifer at Site 1 IC are not conducive to artificial recharge via surface spreading basins. The upper approximately 50 ft of alluvial sediments is primarily silt and clay (see Appendix B), which would nol be conducive to the vertical percolafion of surface water. The stratigraphy and aquifer characterisfics of the shallow alluvial aquifer at Site 1 IC are not conducive to arfificial recharge via injection wells. The only sand layer in the alluvium is less than 3 ft thick, which is nol thick enough to accommodate storage of large volumes of water. The groundwater production potential of the alluvial aquifer is also limited. The fine-grained nature of the sediments between 50 ft and bedrock surface (156 ft bgs) are nol anficipated to yield a significant quanfity of water to wells. GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Waler Authority 124 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 • Groundwater production from the bedrock aquifer would likely be limited. The sandstone sediments that would be expected to be more permeable have varying percentages of siltstone, which will decrease the permeability. Furthermore, pumping tests of the sandstone aquifer near the Desaller Site, suggest that the sandstone aquifer has a relatively low hydraulic conductivity and would not be conducive to yielding large quanfifies of groundwater to wells. Based on this testing, producfion rates from the bedrock aquifer would likely be less than 50 gpm. • Foilowing the above conclusion, the potenfial for artificial recharge by injecfion into the bedrock aquifer beneath Site IIC does nol appear to be promising. As discussed previously, injection rales would likely be as litfie as one half of the esfimated producfion rale (less than 25 gpm). In summary, the most promising conjunctive use altemafive for Site 1 IC appears to be artificial recharge by injection into the unconsolidated alluvial aquifer. However, further testing at other more viable conjuncfive use sites is recommended before further tesfing at Site IIC is considered. 10.L12 Site 13 10.1.12,1 Site 13 Conclusions Data collected during the Phase 2 field invesfigafions at Site 13 to evaluate artificial recharge and/or groundwater extracfion potenfial have resulted in the following conclusions; • The strafigraphy and aquifer characterisfics of the shallow alluvial aquifer al Site 13 appear to be conducive lo artificial recharge via surface spreading basins. However, the size of the site may nol be adequate to support arfificial recharge basins. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Waler Authority 125 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 • Artificial recharge by injection into the shallow alluvial aquifer would be limited by the relative lack of a confining layer in the upper 50 fl of sediments (see Appendix B), and the limited space at the site for an injection well. • Groundwater producfion from the shallow alluvial aquifer al Site 13 is very favorable. The alluvial aquifer system is of adequate thickness (approximately 96 ft of unconsolidated, coarse-grained sediments) and permeability to provide suitable yield to production wells. Given the site's proximity to existing City of Oceanside Wells 4 and 5 and the similarities in sediment stratigraphy between the two areas, a well at Site 13 would be expected to have a similar producfion capacity as Wells 4 and 5 (approximately 1,000 gpm). Groundwater producfion from, or injecfion into, the bedrock beneath Site 13 is not considered feasible because the granific bedrock is not permeable. In summary, the most promising altemafive for Site 13 is groundwater producfion from the alluvial aquifer. 10.1.12.2 Site 13 Recommendations To further evaluate the producfion potential of the alluvial aquifer at Site 13, it is recommended to drill and construct a test well al this site. The well should be drilled and tested using the same methods and procedures as employed for the Oceanside Desalter Test Well (D/TW1/PW9). This would include, at a minimum, the collection of soil samples during the drilling of the pilot borehole, geophysical logging, aquifer zone testing, design and construction of a test well (well depth and diameter lo be determined based on examination of the pilot borehole logs and zone testing results). Both step-drawdown and 24-hour constant rale pumping tests should be conducted on the completed well to assess well efficiency, long-term discharge rate, and aquifer GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Waler Authorily 126 ' Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 characteristics (i.e. transmissivity). Details of the production/injection well drilling, construcfion and tesfing should be outlined in detailed technical specifications prepared prior to drilling. 10.1.13 Sitel3A 10.1,13.1 Site 13A Conclusions Data collected during the Phase 2 field investigafions at Site 13A to evaluate artificial recharge and/or groundwater extracfion potential have resulted in the following conclusions: • The stratigraphy and aquifer characteristics of the shallow alluvial aquifer at Site 13A appear to be conducive to artificial recharge via surface spreading basins. • Although groundwater levels beneath Site 13A are currently too shallow to allow for the recharge of surface water via surface recharge basins, future lowering of groundwater levels as a result of increased groundwater production within the Mission Basin may result in a groundwater level low enough to store water in the subsurface. • As discussed for olher potential artificial recharge sites, the depth at which groundwater recharge becomes feasible depends primarily on the permeability of the sediments. From the borehole log at the site, the sediments are predominantly sand, which should be relatively permeable. Assuming the permeability is as high as suggested by pumping tests at nearby Wells 4 and 5, an addifional 10 ft of drawdown should be adequate to accommodate artificial recharge via surface spreading basins al Site 13A. However, these conclusions should be verified through a controlled pilot recharge lest at the site. • Implemenfing an arfificial recharge program on Site 13A will be contingent on idenfifying enough space to support artificial recharge basins. GEOSCIENCE Support Services, Inc.' Tetra Tech/San Diego County Waler Authority 127 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Artificial recharge by injecfion into the shallow alluvial aquifer is nol feasible due lo shallow bedrock (approximately 55 fl bgs). • Groundwater production from the shallow alluvial aquifer at Site 13A is not feasible due to shallow impermeable bedrock. • Groundwater production from, or injection into, the bedrock beneath Site 13A is not considered feasible because the granitic bedrock is not permeable. In summary, the most promising alternative for Site 13A is artificial recharge via surface spreading basins. Recommendations for further testing to verify this are provided in the following secfion. 10.1.13.2 Site 13A Recommendations To further evaluate the potential for artificial recharge at Site 13A, it is recommended lo conduct a sub-scale pilot recharge test. The pilot lest would include the construcfion of a sub-scale (0.5-to 1-acre) rectangular spreading basin constructed of earthen berms. Monitoring wells (both within and surrounding the spreading basin) would be necessary to enable the collecfion of groundwater level and quality data before, during and after the test. Ideally, the test would be conducted for several months and the source of water for the test would be the same as would be used for the large-scale recharge program. The details of a pilot recharge test at Site 13A should be prepared in the form of a pilot test work plan that describes the recharge basins, monitoring facilifies, and data collection procedures (types and frequency of measurement). GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 128 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 10.1.14 Site 32 10.1.14.1 Site 32 Conclusions Data collected during the Phase 2 field invesfigafion at Site 32 to evaluate arfificial recharge and/or groundwater extracfion potential have resulted in the following conclusions: Based on available data, the stratigraphy and aquifer characteristics of the alluvial aquifer at Site 32 are nol conducive to artificial recharge via surface spreading basins. The interval from approximately 30 lo 50 ft bgs of alluvial sediments contains a high percentage of silt (see Appendix B), which would not be conducive to the vertical percolafion of surface water. Although groundwater levels beneath Site 32 are currently too shallow to allow for the recharge of surface waler via surface recharge basins, future lowering of groundwater levels as a result of increased groundwater producfion within the Mission Basin may result in a groundwater level low enough to store water in the subsurface. • As discussed for other potential artificial recharge sites, the depth at which groundwater recharge becomes feasible depends primarily on the permeability of the sediments. From the borehole log at the site, the sediments below approximately 50 fl bgs are predominanfiy sand with some gravel layers, which should be relatively permeable. Assuming the permeability is as high as suggested by pumping tests at the nearby Desalter Wells, an addifional 10 ft of drawdown should be adequate to accommodate artificial recharge via surface spreading basins at Site 32. However, these conclusions should be verified through a controlled pilot recharge test al the site. Arfificial recharge by injecfion into the deep alluvial aquifer appears to be more favorable than surface spreading at Site 32. The relatively high percentage of fine-grained sediments in the upper 50 fl may be adequate to allow for the injecfion of waler. GEOSCIENCE Support Services, Inc. Telra Tech/San Diego Couniy Water Authority 129 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 • . Groundwater production from the shallow and deep alluvial aquifers at Site 32 is very favorable. The alluvial aquifer system is of adequate thickness (approximately 160 ft of unconsolidated, coarse-grained sediments) and permeability to provide suitable yield to producfion wells. A well al this site could have an instantaneous production capacity of as high as 2,000 gpm. Il is nol known, based on available data, whether groundwater producfion from or artificial recharge into the bedrock aquifer at Site 32 is feasible. Although sedimentary bedrock was encountered during the drilling of monitoring well 32/Bl/MWl, the thickness and permeability of the sedimentary formafion in this area has not been investigated. In summary, viable altemafives for Site 32 include both alluvial aquifer, groundwater producfion and recharge via injection wells. Recommendafions for further testing to verify this are provided in the following section. 10.1.14.2 Site 32 Recommendations Given the available data. Site 32 (and its immediate vicinity) is a viable producfion well site and is recommended for a future producfion well. The well should be drilled and tested using the same methods and procedures as employed for the Oceanside Desaller Test Well (D/TW1/PW9). This would include, at a minimum, the collecfion of soil samples during the drilling of the pilot borehole, geophysical logging, aquifer zone testing, design and construcfion of the well (well depth and diameter to be determined based on examinafion of the pilot borehole logs and zone tesfing results). Both step-drawdown and •24-hour constant rate pumping tests should be conducted on the completed well to assess well efficiency, long-term discharge rate, and aquifer characterisfics (i.e. transmissivity). Details of the production well drilling, construcfion and tesfing should be oufiined in detailed technical specificafions prior to drilling. GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Waler Authorily 130 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 In the event that samples collected during the drilling of the pilot borehole for the production •well confirm that Site 32 is promising for aquifer recharge via injecfion wells, it would be recommended to construct the production well at this site to also function as an injection well. Following construction, it would be recommended lo conduct an . injecfion test to assess the ability of the aquifers to accept recharge through an injection well. The technical specifications described above would include provisions for constmction and testing of an injection well at this site. 10,1.15 Desalter Site 10.1.15.1 Desalter Site Conclusions Data collected during the Phase 2 field invesfigafions at the Oceanside Desalter Site to evaluate artificial recharge and/or groundwater extracfion potential have resulted in the following conclusions: Based on available data, the strafigraphy and aquifer characteristics of the alluvial aquifer in the vicinity of the Oceanside Desaller Site are conducive to artificial recharge via surface spreading basins. During the D/TW1/PW9 pumping test, water discharged into the retention basin adjacent to the Desalter Site readily percolated into the ground. • The depth to groundwater beneath the Desalter Site (approximately 20 fl bgs) appears to be deep enough to accommodate artificial recharge of surface water via surface recharge basins, given the relatively high permeability of the shallow alluvial sediments in this area. However, this should be verified through further tesfing. Arfificial recharge by injection into the deep alluvial aquifer appears to be favorable al the Desaller Site. The aquitard separating the shallow and deep alluvial aquifers would likely be adequate to allow for the injection of waler. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authority 131 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 • Groundwater production from the deep alluvial aquifer at the Desalter Site is very favorable. The alluvial aquifer system is of adequate thickness (approximately 56 ft of unconsolidated, coarse-grained sediments) and permeability to provide suitable yield to production wells. As shown by the pumping test at D/TW1/PW9, wells in this area can produce as much as 2,000 gpm. • Based on aquifer zone testing and a vertical flow meter survey during the D/TW1/PW9 pumping lest, groundwater production from or artificial recharge into the bedrock aquifer at the Desalter Site is not favorable. Zone tesfing suggests that producfion rales from the bedrock aquifer would be less than 50 gpm. Injecfion rales would be expected lo be one half of the production rate (i.e. 25 gpm) or less. In summary, viable altemafives for the Desalter Site include alluvial aquifer groundwater producfion as well as recharge via surface spreading basins or injection wells. Recommendafions for further tesfing to verify these preliminary conclusions are provided in the following secfion. 10.1.15,2 Desalter Site Recommendations Given the number of producfion wells (four) already on the Desalter Site properly, it is recommended to operate these wells for al least one year and assess groundwater level impacts from the combined pumping before drilling additional wells at this site. To further assess the feasibility of artificial recharge using surface spreading basins near the Desalter Site, it is recommended to conduct a sub-scale pilot recharge test. The exisfing storm water retenfion basin immediately north of this site could be used for the pilot basin although, given the relafively large size of the exisfing basin (approximately 11 acres), it would be necessary to construct a smaller "subbasin" for testing purposes. Four to five monitoring wells GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily 132 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 •Aug-04 would be recommended within and surrounding the basin lo assess groundwater mounding and migration characteristics. Ideally, the lest would be conducted for several months and the source of water for the lest would be the same as would be used for the large-scale recharge program. The details of a pilot recharge test at the Desaller Site should be prepared in the form of a pilot test work plan that describes the recharge basins, monitoring facilifies, and data collecfion procedures (types and frequency of measurement). 10.2 Potential Geohydrologic Constraints to Conjuctive Use in the Mission Basin Potential geohydrologic constraints lhal should be considered prior to implementafion of a conjunctive use program in the Mission Groundwater Basin include: • Potenfial environmental impacts lo the riparian habitat in the vicinity of the San Luis Rey River from lowering of groundwater levels, • Potenfial for land surface subsidence due to groundwater withdrawal during periods when groundwater producfion exceeds inflow from natural and artificial recharge, and • Potential for liquefaction during periods of high groundwater levels during periods when natural and artificial recharge exceeds groundwater producfion. These potenfial constraints are discussed in more detail in the following subsections. GEOSCIENCE Support Services, Inc. Telra Tech/San Diego Couniy Water Authority 133 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 10.2.1 Potential Environmental Impacts to the Riparian Hahitat Along the San Luis Rey River Future lowering of the groundwater level in the Mission Basin as a result of conjuncfive use activities would have lo be managed to avoid impacts to the riparian habitat along the San Luis Rey River. Lowering of the groundwater level will be necessary to accommodate future artificial recharge, whether il is from surface recharge basins or injecfion wells. The amount of groundwater level lowering necessary lo accommodate future recharge will depend on the permeability of the shallow subsurface sediments and the amount of artificial recharge to be applied. Preliminarily, an addifional 10 ft of groundwater level lowering should be adequate lo accommodate artificial recharge in many areas of the Mission Basin. However, this will need to be tested on a sile-by-site basis (see Secfions 10.1.3 through 10.1.15). Conceptually, given the findings from the Phase 2 invesfigations, artificial recharge could be maximized at the sites along the San Luis Rey River (i.e. Site 2A, the Desalter Site, Site 3B, Site 3C, Site 9A, Site 7A, and Site 13A) while focusing producfion at sites in the southem portion of the basin lhal are the furthest away from the river but have the greatest potential for groundwater production (Sites. 1 OA and 32). In so doing, excessive groundwater level lowering direcfiy beneath the river could be minimized. 10.2.2 Potential for Land Subsidence Land subsidence as a result of groundwater, or other subsurface fluid, withdrawal has been recognized in many parts of Califomia (Meade, 1968, Helm, 1975, Ireland et al., 1984, Poland and Ireland, 1988, Sneed and Galloway, 2000). In all cases, the measured subsidence is a function of excessive lowering of groundwater (or fluid) levels in areas where a significant portion of the subsurface consists of very fine-grained sediments (clay). In many cases, subsidence can be correlated with areas that historically were flowing artesian (the groundwater level was at or above the land surface). GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 134 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 Land surface subsidence is not expected to be a significani geohydrological constraint to conjuncfive use projects in the Mission Basin. Two condifions are generally necessary for land surface subsidence to occur: • Thick layers (typically 10s to 100s of ft thick) of laterally extensive clay, and • Sustained (i.e. decades) lowering of groundwater levels, particularly in areas where groundwater levels were historically shallow or al the ground surface. Sill and/or clay layers have been observed in the central and western portions of the Mission Basin. However, these fine-grained layers are thin (generally less than 20 fl thick), not laterally extensive, and typically have a relatively high percentage of sand. Laboratory tesfing for consolidation potential performed on selected silt and clay samples indicaled that these layers do not consolidate or expand when saturated. Thus, the potenfial for land surface subsidence due to consolidafion of the silt and clay layers in the Mission Basin is low. Excessive groundwater level declines (i.e. hundreds of ft of decline) will not occur in the Mission Basin as a result of future conjuncfive use projecls. The total thickness of the alluvial aquifer is only 100 to 200 ft and will nol accommodate the amount of groundwater level drawdown typically observed in areas where land surface subsidence is a problem. Furthermore, the amount of drawdown allowed for future conjunctive use projects is limited lo avoid potential environmental impacts to the San Luis Rey River (see Section 10.2.1). Thus, given the nature and characteristics of the clay layers in the Mission Basin and the expected operation of the groundwater basin, land surface subsidence is not expected to be a geohydrologic constraint for future conjuncfive use projecls. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 135 Geohydrologic Investigation - Lower San Luis Rey Rivcr Valley 31-Aug-04 10.2.3 Potential for Liquefaction Liquefacfion is the process whereby saturated unconsolidated sediment loses cohesion during periods of intense, sustained ground shaking (i.e. earthquake). In effect, the soil properties shift from a solid state to a liquid state. Liquefacfion typically occurs at depths of less than 50 ft bgs but saturated sediments less than 30 ft bgs are the most suscepfible (Matti and Carson, 1991). Because existing and proposed groundwater level condifions in the Mission Basin are susceptible to liquefaction, further invesfigation is recommended lo collect the data necessary to evaluate this constraint. Additional data would be collected through a borehole drilling or cone penetrometer test (CPT) and should be conducted in accordance with the procedures outlined in Martin and Lew (1999). 10.3 Bonsall Basin 10.3.1 Site 26/27 Conclusions Data collected during the Phase 2 field investigations at Bonsall Basin Site 26/27 to evaluate groundwater producfion potential have resulted in the following conclusions: Groundwater production from the alluvial aquifer at Site 26/27 is very favorable. The alluvial aquifer system is of adequate thickness and permeability to provide suitable yield to production wells. Potential production well yield from this aquifer is not known but •could be as high as 1,000 gpm if the aquifer permeability is as high as observed in the vicinity of City of Oceanside Wells 4 and 5. • Groundwater production from the bedrock beneath Site 26/27 is not considered feasible because the granitic bedrock is not permeable. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 136 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Groundwater production from the alluvial aquifer at Site 26/27 appears lo be a viable altemative for this site. However, this should be verified through addifional testing. 10.3.2 Site 26/27 Recommendations To further evaluate the production potenfial of the alluvial aquifer af Site 26/27, it is recommended to drill and construct a test well at this site. The well should be drilled and tested using the same methods and procedures as employed for the Oceanside Desalter Test Well (D/TW1/PW9). This would include, al a minimum, the collection of soil samples during the drilling of the pilot borehole, geophysical logging, aquifer zone testing, design and constmction of a test well (well depth and diameter to be determined based on examination of the pilot borehole logs and zone testing results). Both step-drawdown and 24-hour constant rate pumping tests should be conducted on the completed well to assess well efficiency, long-term discharge rate, and aquifer characteristics (i.e. transmissivity). Details of the test well drilling, construction and tesfing should be outlined in detailed technical specificafions prepared prior to drilling. GEOSCIENCE Support Services. Inc. Telra Tech/San Diego County Water Authority 137 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 11.0 REFERENCES American Society for Tesfing and Materials, 1994. ASTM Standards on Groundwater and Vadose Zone Investigations. Second Edition. ASL Consulfing Engineers, 2000. San Diego Countv Water Authority Groundwater Storage and Recoverv Project: Lower San Luis Rey River Valley, Technical Report - Phase 1. Dated April, 2000. Atwater, T., 1970. Implications of Plate Tectonics for the Cenozoic Tectonic Evolufion of Westem North America. Bulletin Geological Society of America, vol. 81. Bouwer, H., 2002. Artificial Recharge of Groundwater: Hydrogeology and Engineering. Hydrogeology Joumal, vol. 10, pgs. 121-142. California Department of Water Resources, 1956. Santa Margarita River Invesfigafion. State of Califomia, Department of Public Works, Division of Water Resources, Bulletin No. 57, Vols. I and II. Califomia Department of Waler Resources, 1958. Sea-Water Intrusions in Califomia. State of Califomia, Department of Public Works, Division of Waler Resources, Bulletin No. 63. Califomia Department of Waler Resources, 1960. Waler Oualitv Condifions and Effects of Recharge with Sewage Effluent in Mission Basin. San Luis Rey Valley. San Diego Countv. Report to San Diego Regional Water Pollution Control Board (No. 9). Califomia Department of Water Resources, 1967. Groundwater Occurrence and Quality. San Diego Region. Bullefin 106-2. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Waler Authority 138 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 - Aug-04 California Department of Water Resources, 1984. San Diego Cooperative Groundwater Studies. Reclaimed Water Use. Phase II. City of Oceanside, 1991. Draft Report on the Aquifer Performance Test. Prepared by NBS Lowry and Stetson Engineers, Inc., Oceanside, CA: September 1991. City of Oceanside, 2004. City of Oceanside Mission Basin Desalting Facility Groundwater Recovery Program, Agreement No. A04969, FY 1998 to 2003. Personal Communication, Judith Ludlow, Department of Waler Resources, March 9, 2004. Crippen, J.R., 1965. Natural Waler Loss and Recoverable Water in Mountain Basins of Southern Califomia. U.S. Geological Survey Professional Paper 417-E. Ellis, J.E., Lee, C.H., 1919. Geology and Groundwaters of the Western Part of San Diego County Califomia. United Slates Geological Survey Water-Supply Paper 446. Freeze, R.A. and Cherry, J.A., 1979. Groundwater. Prentice-Hall. Gasul, G. and Higley, R., 1977. Guide to San Diego Area Strafigraphy: The Edwin C. Allison Center. Prepared for American Associafion of Petroleum Geologists - SEG Petroleum Explorafion School Field Trip. Geopacifica, 1995. Results of Pump Tests - Well Nos. 3. 4 and 5. RO Plant and North River Road. Oceanside. California. Letter Report Dated June 19, 1995. GEOSCIENCE Support Services, Inc., 1993. Waler Resources Management Services: Phase 1 Geohydrologic Invesfigation. Prepared for the Rainbow Water District (formerly the San Luis Rey Municipal Water District). GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Waler Aulhorily 139 Geohydrologic Investigation - Lower San Luis Rey River Valley 31-Aug-04 Geotechnical Consultants, Inc. (Geotechnical Consultants), 1990. Appendix C-3: Preliminarv Assessment of Geologic and Hydrogeologic Conditions Gregory Canyon Site. Prepared for the U.S. Dept. of the Interior, Bureau of Land Management and the County of San Diego Dept. of Public Works, Solid Waste Division. Hantush, M.S., 1964. Hydraulics of Wells. In Advances in Hydroscience. Vol. 1. Academic Press, New York. Helm, D.C., 1975. One-dimensional Simulation of Aquifer System Compacfion Near Pixlev, Califomia, 1). Constant Parameters. Water Resources Research, Volume II, No. 3. Ireland, R.L., Poland, J.F., and Riley, F.S., 1984. Land Subsidence in the San Joaquin Valley. Califomia. as of 1980. U.S. Geological Survey Professional Paper 437-1. Izbicki, J.A., 1985a. Evaluafion of the Mission, Santee. and Tijuana Hydrologic Subareas for Reclaimed-Water Use. San Diego County. California. U.S. Geological Survey Water-Resources Investigations Report 85-4032. Izbicki, J.A., 1985b. Maps of the Bonsall Area of the San Luis Rev River Valley. San Diego County. Califomia. U.S. Geological Survey Water-Resources Investigafions Report 85-4112. Jacob, C.E., 1950. Engineering Hydraulics. J. Wiley and Sons, New York. Jennings, C.W.,"1994. Fault Activity Map of Califomia and Adjacent Areas, with Locafions and Ages of Recent Volcanic Erupfions. Califomia Division of Mines and Geology, Geologic Data Map No. 6. Scale 1:750,000. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Waler Authorily 140 Geohydrologic Investigation - Lowcr San Luis Rey River Valley 31-Aug-04 Johnson, A.I., 1967. Specific Yield - Compilation of Specific Yields for Various Materials. U.S. Geological Survey Water Supply Paper 1662-D. Prepared in Cooperafion with the Califomia Department of Water Resources. Martin, G.R. and Lew, M. 1999. Recommended Procedures for Implementation of DMG Special Publication 117. Guidelines for Analyzing and Mitigafing Liquefacfion Hazards in Califomia. Southem Califomia Earthquake Center, University of Southem Califomia. Matfi, J.C. and Carson, S.E., 1991. Liquefaction Susceptibility in the San Bemardino Valley and Vicinity, Southem Califomia - A Regional Evaluation. U.S. Geological Survey Bulletin 1898. Meade, R.H., 1968. Compaction of Sediments Underlying Areas of Land Subsidence in Central Southern Califomia for a Postulated Waler Level Lowering, 1965-2015. U.S. Geological Survey Open-File Report, Water Resources Division, Sacramento, Califomia. Moreland, J.A., 1974. Hydrologic and Salt Balance Investigafions Ufilizing Digital Models. Lower San Luis Rev River Area, San Diego County. Califomia. U.S. Geological Survey Water-Resources Invesfigations 24-74. NBS Lowry Engineers and Planners, Inc., 1992. Phase 1 Report: Balanced Water Management Project. Prepared in conjunction with Stetson Engineers, Inc. for the City of Oceanside. NBS Lowry Engineers and Planners, Inc., 1993. Groundwater Recharge and Water Duality Issues: 2 MGD San Luis Rey Basin Desalfing Facility. Prepared in conjunction with Michael Welch, Ph.D., P.E. for the City of Oceanside Water Utilifies Department. NBS Lowry Engineers and Planners, Inc., 1994. Emergency Storage Proiect - Groundwater Feasibility Study. Prepared for the San Diego County Water Authority. GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority 141 Geohydrologic Investigation - Lower San Luis Rey River Valley 31 -Aug-04 Norris, R.M. and Webb, R.W., 1990. Geology of Cahfomia. John Wiley & Sons, New York. PCR Services Corporation (PCR), 2002. Gregorv Canyon Landfill: Final EIR. Prepared for the County of San Diego, Department of Environmental Health. State Clearinghouse No.1995061007. Dated December 2002. Poland, J.F., and Ireland, R.L., 1988. Land Subsidence in the Santa Clara Valley. Califomia. U.S. Geological Survey Professional Paper 497-F. RECON, 1996. San Luis Rey River: Waler Oualitv Management Plan. Prepared for the Couniy of San Diego Department of Parks and Recreation. Skrivan, J.A., 1976. Predicted Effects of a Proposed Water-Resource Management Plan in the Lower San Luis Rey River Valley. California. Using Digital Ground-Water Flow Models. U.S. Geological Survey, Open-File Report 76-754. Sneed, M. and Galloway, D.L., 2000. Aquifer-System Compacfion: Analyses and Simulafions - the Holly Site, Edwards Air Force Base. Antelope Valley. Califomia. U.S. Geological Survey Water-Resources Investigations Report 00-4015. Southem Califomia Soil Testing, Inc. (SCS&T), 2003. Resisfivity hnaging Results for Five Sites within the San Luis Rev River Drainage Oceanside. Califomia. Prepared for Tetra Tech, Inc, Stetson Engineers, Inc., 1991. Draft Report on the Aquifer Performance Test. Citv of Oceanside 2.0 MGD Desalter Plant Project. Dated September 1991. GEOSCIENCE Support Services, Inc. Telra Tech/San Diego Couniy Water Authority 142 Geohydrologic investigation - Lower San Luis Rey River Valley 31-Aug-04 Tan, S.S., and Kennedy, M.P., 1996. Geologic Maps of the Northwestem Part of San Diego County. Califomia: Plate 1. Geologic Maps of the Oceanside. San Luis Rev, and San Marcos 7.5' Quadrangles. Califomia Division of Mines and Geology Open-File Report 96-02. Telra Tech, Inc. (Tetra Tech), 2001. Lower San Luis Rey Groundwater Storage and Recovery Feasibility Study: Phase 2B-Baseline Environmental. Hydrology, and Preliminarv Groundwater Modeling. Report Dated November 2001. U.S. Geological Survey (USGS); 1976. Summary Appraisals of the Nation's Ground-water Resources - Califomia Region. Professional Paper 813-E. U.S. Geological Survey (USGS), 2004. "Real-Time Data for Califomia". hllp://walerdata.usgs.gov/ca/nwis/rt. Welch, M. R., 1996. Supplemental Groundwater Pumping Analysis: Expansion of Oceanside Mission Basin Brackish Groundwater Desalting Facility lo a Potable Water Production Capacity of 6.37 MGD. Prepared for the City of Oceanside. Dated Febmary 1996. Westem Regional Climate Center (WRCC), 2003. "Period of Record General Climatic Summary - Temperature", http://www.wrcc.dri.edu/ (15-Mar-2004). Ziony, J.I., CM. Wentworth, J.M. Buchanan-Banks, and H.C. Wagner, 1974. Preliminary Map Showing Recency of Faulfing in Coastal Southem Califomia. U.S. Geological Survey Miscellaneous Field Studies Map MF-585. GEOSCIENCE Support Services. Inc. Tetra Tech/San Diego Couniy Waler Authorily 143 APPENDIX A Site-Specific Figures GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Appendix A Geohydrologic Investigation - Lower San Luis Rey River Valley APPENDIX A SITE-SPECIFIC FIGURES CONTENTS Description Page Site 1 - Site Plan A-1 Site 2A-Site Plan A-2 Site 2B-Site Plan '. A-3 Site 3B--Site Plan ;.A-4 Site 3C-Site Plan A-5 Site 7A-Site Plan A-6 Site 9A-Site Plan A-7 Site lOA-Site Plan ;.A-8 Site 11 - Site Plan ; A-9 Site liC-Site Plan A-10 Site 13-Site Plan A-11 31-Aug-04 GEOSCIENCE Support Services, Inc. A-i Telra Tech/San Diego County Water Authority Appendix A Geohydrologic Investigation - Lowcr San Luis Rey River Valley CONTENTS (Continued) Description Page Site 13A-Site Plan A-12 Site 32-Site Plan A-13 Desalter Site - Site Plan A-14 Site 26/27-Site Plan A-15 31-Aug-04 GEOSCIENCE Support Services, Inc. A-ii t»D.{>;«.mdftntm-..C* SIJs) T il S .i20,ClDit>rwnl.CA SlJll R.5 W, R.4 W, T.n S. sRi5.0=«221,OBXW5ni.C/ BU11 R.4 W T.ll S. Sources of Data: TclraTccli, Inc. (Aerial Pholo), 20Q1. TctraTcch, Ire, (Exisling Wells and Invesligaiion Sile5), 2003. U.S. Geological Survey (Oiher Wells - USGS Well Database), 2002, 31-AUG-04 GEOSCIENCE Pi5,Sa'220,Cla'pm<fi,CA rp:<SCfi)K»<r7c7 Fit (SCSI DJ&WOI •Kir* 3!waet.;arn 0 250 500 Feet GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY APPENDIX A-4 Site 3B-Site Plan T.ll S. Sources of Dala: TciraTccli. Inc. (Aerial Photo), 2002. TctraTecK Inc. (fixisting Wells and Investigadon Sites). 2003. U.S, Geological Survey (Other Wells - USGS Well Database), 2002. GEOSCIENCE 250 500 Feel GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY APPENDIX A-5 Site 3C - Site Plan R.4 W. T.ll S, 5« FEJI: CW6I B»CS3 •Awn 3S!r*«t( com R-4 W. T.ll S. Sources of Data: TetiaTcch, Inc, (Aenal Photo), 2002. TeiraTech, Inc. (Existing Wells and Invciligalion Sites), 2003. U S Geological Survey (Other Wells - USGS Well Database). 2002. 31-AUG-04 GEOSCIENCE P6 Ba.SSD.Ca'PSWH.CA Vim 250 500 Feel GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY APPENDIX A-7 Site 9A - Site Plan T l i S, GEOSCIENCE P.O.!ai,Oa^cror,,CA SHsi 250 500 Feet GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY APPENDIX A-8 Site lOA - Site Plan R.4 W T.I 1 S, T.ll S, Sources of Data: TelniTcch, Inc. (Aerial Photo}, 2002. TetraTedi, Inc. (Exisling Wells and Investigation Sites), 2003, U.S. Geohgicil SiiTvey (Olher Wdls - USGS Well Database), 2002 GEOSCIENCE Eel tKKJKffl^OT f—: («S1 9»MP3 250 500 Feet GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY APPENDIX A-9 Site 11-Site Plan R.5 W. R.4 W T.ll S. V 'ti^?" t=-i--t 1^-.- -••fri .- ./•''• - , TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY APPENDIX A-10 Site lie-Site Plan R.4 W. T,n s. .Source; of Dam: TctraTech, Inc. {Aenal Photo). 2003, TetraTech. Ine. (hxisling Wells and hivcstigation Sues). 2003. U.S. Geological Siirvev (Other Wells - USGS Well Databascl, 2002. GEOSCIENCE 250 500 Feet GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY APPENDIX A-11 Site 13 - Site Plan T.n s. GEOSCIENCe IK. >S0^ 9^fl707 Ftjs: CHJSlSKiWeS 250 500 Feci GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY TETRA TECH / SAN DIEGO COUNTV WATERAUTHORITY APPENDIX A-12 Site 13A - Site Plan T. 11 S. 31-AUG-04 GEOSCIENCE GEOSCIENCE Sufporl Seivices, Inc. aO.BoiZM.CIaCJiionf.CA 9l7n Tel: (909) 930-0707 -ac (909)920-04(33 WTrtw.q ss** ^er. com 250 500 Feet GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REV RIVER VALLEY TETRA TECH/ SAN DIEGO COUNTV WATER AUTHORITY APPENDIX A-13 Site 32 - Site Plan R,4 W TU S. QE05Ci£wC£ S«t*mt Stir/uw.int PO DaiIZO, dotmort.O 61711 R-3 W T,10S, Sources of Data: TetraTech, Inc. (Aerial Photo}, 2002. TctraTech, Inc. (Existing Wells and Invesligaiion Sites), 2003, U.S. Geological Survey (Olher Wells - USGS Well Database), 2002 31-AUG-04 GEOSCIENCE KV.W s^VKB t r cum 0 • 250 500 Feet GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY TETRA TECH/ SAN DIEGO COUNTV WATER AUTHORITY APPENDIX A-15 Site 26/27 - Site Plan APPENDIX C Laboratory Soil Analytical Reports GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Appendix C Geohydrologic Investigation - Lower San Luis Rey River Valley APPENDIX C SOIL PHYSICAL PROPERTIES Soils were visually classified in accordance with the United Soil Classification System (USTM). Laboratory moisture contents and dry unit weights were determined for the ring samples obtained in the field. Soil moisture content and dry unit weights are shown in Table 11. Consolidation Testing Consolidation tests were perfonned on selected undisturbed soil samples. The test procedure for all three samples was identical. The consolidation apparatus is designed to receive a one-inch high soil filled brass ring. Loads are applied in several increments in a geometric progression and the result deformations are recorded at selected time intervals. Porous stones are placed in contact with the top and bottom of each specimen to permit addition and release of pore fluid. Inundation of the samples was perfonned at a load of one kip per square foot (ksf), and the test results are shown on the enclosed semi-log plots of deformation (%) versus compressive stress (ksO. Hydraulic Conductivity Hydraulic conductivity (also referred to as triaxial permeability) was performed for typical unconsolidated sandy soils according to ASTM D-5084-90. This test method provides a means for determining hydraulic conductivity at a controlled level of effective stress. Test results are reported in centimeters per second (cm/sec). 31-Aug-04 GEOSCIENCE Support Services, Inc. C-1 Telra Tech/San Diego Couniy Water Authority Geohydrologic Investigation - Lower San Luis Rey Rivcr Valley Appendix C SUMMARY OF PEEMKABnJTY TEST RESULTS PROJECT NAME San Uie Rey Storage Fecflity PROJECT NOJ tm DATE: 10-2 W EGLJOS NOwOS-OWQI CLiENT; Soumsm Celffomfa SUMMARIZED BY; X-W DEPTH ^501QTURE DRY EFPEcnve SATURATE^ EFFECTIVE- NO CONTErJT DENSITY COMFINED HYDRAULIC POROSrrY ASTM ASTM PRESSURE CONDUCnViTY D221Q D2B37 ASTM DS0S4 (%) (pcf) (psi) (cm/eec) {%) 2A.B2 145-148 15.0 90.9 4O.0 5.0E-Q0S 46.2 2A-BZ 241-242 8.0 m.s 40.0 tlE-OOS 4Q.7 3a-S2 na-ira 90-1 40.0 2.2E~005 39.7 3B-8Z 252-2S3 12.3 93,1 40.0 7.5&O0S 38.4 11C-B1 7B-76.5 30.0 B7.1 42.6 $.4E-006 42.0 0-B2 206-207 iQ.n S4.8 40.0 42.9 D-B2 401-402 11£ 10S.4 40.0 8.3E-0Q5 39J 31 -Aug-04 C-2 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix C 1.20 1.1D 1,00 Q.90 0.80 0.70 § Q.60 O 0.60 0.40 0.30 0.2D 0-10 • r- teases ^. « ^ i O.QD 0.10 0.20 0,30 0.40 Q.SO O.S0 0.70 0.80 0.90 100 HO 1.2£. PORE VOLUME (CC) SYMBOL SAliilPLE ID DEPTH .,{FT) SOIL T/PE DRY DENsrrv (PCF) MOISTURE CONTENT {%» TOTAL PQROSiTY P0RI^31TY 0 Wsil 2A^a 145-146 SP S0.9 15.0 Q.462 Q^§2 ^•:-d^^;-;v. Environmental ^^^g Geotechnology Uaboratoiy PROJECT N.iHE: aat\ Uil8 Rs> Sbrsgs Faiyiily SoaAi-tlTssBns 5SL Proiect «Jc,:QWH9.001 31 -Aug-04 GEOSCIENCE Support Services, Inc. C-3 Tetra Tech/San Diego Couniy Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix C 1,20 1.10 1.00 0.90 OiJO 0.7Q 0.6D O 0.50 0.40 • 0.30 0.20 0.10 0.00 &' O.OO O.lfl 0.2Q O.ao 0.40 0.60 0,60 0,70 0.S0 OJO 1-00 1.10 1.23 P(5RE VOLUME {CC} SYMBOL SAMPLE ID DEPTH . (FT) SOIL TYPE DRY DENSITY tPCF) MOISTURE CONTENT t%) TOTAL PQROSm' EFFECTIVE POF:OSrrY O Wea 2A-B2 241-242 SC BB.8 8.0 0.430 t<407 w^^v:;-;; Environmental EvMig^g Gsotschnology LaDoratofy PROJECT WjvME: San LufB RBV Sloram FacKty SoJIAodTestlna SGL Projflfitdo.: 03-OS6-C01 BREAKTHROUGH METHOD 31-Aug-04 GEOSCIENCE Support Services, Inc. C-4 Tetra Tech/San Diego Couniy Water Authority Geohydrologic Invesligaiion - Lower San Luis Rey River Valley Appendix C 1.20 1.10 1.QQ 0.90 0.80 o.ro o g 0.60 O.S0 0,40 0,30 0.20 Q.10 0.00 / r 0.00 0.10 0-20 0.30 Q.40 0.SO 0.6O 0.70 0.50 O.M 1-00 110 ISC PORE VOLUME (CC) SYMBOL SAMPLE ID DEPTH (FT) SOIL 7YP£ •' bftY DENSITY (PCF) MOISTURE CONTEHT m TOTAL POROSITY EFFECTIVE POROSITY 0 Well 3a-B2 175-17S BM 88.1 e.8 0.423 .\ Environmenfal ^ Geotechnolt^y ^ Laboratory PROJECT N.QjVjE: San Im Ru,' SWrase FacJUiy Clent SouB-ietn Calfomta SuliA-KlTesflng E£3L Project f^d.: O^OSfi-OOl BROMIDE BREAKTHROUGH METHOD 3]-Aug-04 C-5 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego Couniy Water Authorily Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix C 1.20 1.10 1.00 0.90 O.B0 0.70 0,60 0.60 0.40 030 0.20 0.10 0.00 Q.OO 0.10 020 0.30 0.40 0.5a O.BO 0.70 O.SO 0.00 100 tio PORgVOLUiVIS(GC) SY^aOL SAMPLE ID DEPTH (FT) SOIL TYPE DRY (PDF) MOISTURE CONTENT t%) TOTAL POROSITY EFFECTIVE POBOsmr 0 Well 3B-a2 £62-253 SM 93.1 1E.3 0^3 D 394 EnvirDnmental Geotschnol Lsboratory Geotechnology PRt5JECT^oAtE: San Luis R0|' StDfage PatlEty Client Soinham Catiiornfei SoBAiiITealtnfi EGL Proiect No.: 03-095-001 3LAug-04 GEOSCIENCE Support Services, Inc. C-6 Tetra Tech/San Diego County Water Aulhorily Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix C 1.20 1.10 1.00, 0-SO 0.80 0.70 O.B0 0.SO Q.40 0.30 Q.20 0.10 0,00 0,00 0.10 0.20 0.30 0.40 0,50 0.60 0.70 0.80 0.90 1.0Q 1.10 1.S.0 PORE VOLUME (CC) SYMBOL SAMPLE ID DEPTH (FT} SOIL TYPE DRY DENSITY (PCF) MOISTURE CONTENT (%) TOTAL POROaiT*' EFF^CTtVE POP:0St'n' 0 Well 11C.B1 7B.78.5 SP 87.1 20.0 Q483 (1.425 i'j^^'^i^ Environmental ^^^^ Geotechnology Laboratory PROJ ECT HAMS; San Luia RtV StDt^ne FaolSty CSant Soutfiem CaffiMtiia Sail/'^^^T(!^ ling EGLPreJec'.j'Jo.; 03-063-001 31-Aug-04 GEOSCIENCE Support Services, Inc. C-1 Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix C 1^0 110 1.00 0.90 0.60 0.70 O.S0 0.40 0,30 0.20 0.10 0.00 • • / — 0.00 0.10 0.20 0.30 0,40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 IE! PORE VOLUME (CC> SYMBOL SAMPLE ID DEPTH .(PT) SOi TYPE • 'tk^ DENSITY (PCF) MOISTURE CONTE^fr (%) TOTAL POROSITY EFFECTIVE POROSiTV 0 Wall D-B2 20S-207 SM 94.9 10,1 v^te^H Envtronmental ""^ CSaatechnoiagy Laboratoiy PROJECT -JAME; SEtn Luis fl:iy Storago FaclBty Ciionb Sflirnm) Califomia Soil) Jill TesBng EgLPrcIfi(.lND.;O3'Oe$.0O1 31-Aug-04 GEOSCIENCE Support Services, Inc. C-8 Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix C 1.10 1-00 o.ao o.ao 0.70 0.60 o.sp 0.40 0.30 o.ao 0.10 0.00 0.00 0;i0 0.20 0.3Q 0.40 0.50 O.BO 0.70 0.80 0.9Q • 1.00 1.10 1.20 PORE VOLUME (CC) SYMSOL SAMPLE 10 DEPTH (FT) SOIL TYPE DRY DEfiSrrY (PCF) MOISTURE CONTENT .,, .. TOTAL POROSITY EFFECTIVE POf.OSfTY 0 Wes D^2 4Q1-402 SP/SM 105,4 11,B 0.307 C.J57 Environmentei ^^^g Geotoahnology Laboratory PROJECT a«rt Lula flEiy .Jtorags FacUiv Client: SDUUJD;^ CaHForrls SoilAiaTeet^na EGlPrpleciNj.: 03^)66-001 BREAKTHROUGH METHOD 31-Aug-04 GEOSCIENCE Support Services, Inc. C-9 Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix C £ 0 a 3 L.,^ 0.1 2 3 ^ 5 0 7 as 2 1 CQMPRESS(V 3 4 & E 7 tfl 10 E STRESS (KSF) 2 a i 5 100 . SYMBOL BORING NO SAMPLE TYPE DEPTH ro SOIL TYPE iWrr. MOISTURE comB^ m iNiT. DRY DENSITY (PCF) iMT, VOID RATIO 0 vm\ 11C-B TUUB 02-62.5 CL XI.? 101.7 o.sse •^i^^^ ENVIRONMENTAL ^•Jj QEOTECHNOLOeY LABORATORY ProjEct Name: San Luto RaySoragi' Faoilily Cllofrti Sotitfiam Cal bmia SoUartiJTBStl.ng EGLPrajedto.: 03-36W}01 31-Aug-04 GEOSCIENCE Support Services, Inc. C-10 Tetra Tcch/San Diego Couniy Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix C 7 ' 0.1 -J 1—u S G T Si) 2 1 COMPRESSW 3 1 B t 7 1 a 10 E STRESS OCSF) i 3 t s 5 7 flS IQO srweoL BORING NO SAMPLE TVPE DEPTH {TO SOIL TYPE iNlT.MOlSTliRE CONTENT m INIT. DRY DENSITY (PCF) !NIT. voin RATIC o Wol! TutiB 75-785 ML 33.3 79.a 1.1Q0 ENVIRONMENTAL 6EOTECHN0LOGY LABORATORY PraJsctNamff. San tiia Rey Sor.i4je FScH)^ Client southern c:&l^rnlQ SoH and Tr-sUng EGL Project ND.:i>i!W001 /ASTM 31-Aug-04 GEOSCIENCE Support Services, Inc. C-11 Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix C o 5 ' 0.1 2 3 4 6 a r 89 3 - 1 COMPRESSIV 3 4 3 « 7 04 10 E STRESS (KSF) t i 4 t 6 J a» 100 SYMSOL BORING NO SAMPLE TYPE DEPTH (FT) SOIL TYPE INIT. MOISTURE CONTENT mr DRY DENSITY (PCF) IMIT. VOID RATIO O Weil 2A-B2 Tube 93-96.5 CL 22.5 96.& 0.7SB ENVIRONMENTAL W^m^M OEOTECHKOLOOY LABORATORY Pn^jeetName: San Lula Roy Soiage facility Ciienl; Soiitham Califomta Soil and Tssiinfl EGL Proiect NO.; 03-056»CI01 10/03 CONSOLIDATION (ASTM D2435) FIGURE 31-Aug-04 GEOSCIENCE Support Services, Inc. C'\2 APPENDIX F l\/lonitoring Well Completion Details GEOSCIENCE Support Service.s, Inc. Tetra Tech/San Diego County Water Authority Append iX F Geohydrologic Investigation - Lowcr San Luis Rey River Valley APPENDIX F MONITORING WELL COMPLETION DETAILS CONTENTS Description Page Monitoring Well lA/Bl/MWl As-Built Diagram ; F-l Monitoring Well 1B/B1/MW2 As-Built Diagram F-2 Monitoring Well 2A/B2/MW1 As-Built Diagram F-3 Monitoring Well 2B/B1/MW1 As-Built Diagram F-4 Monitoring Well 3B/B1/MW1 As-Built Diagram F-5 Monitoring Well 3B/B2/MW2 As-Built Diagram F-6 Monitoring Well 7A/B1/MW1 As-Built Diagram '. F-7 Monitoring Well lOA/Bl/MWl As-Built Diagram F-8 Monitoring Well llC/Bl/MWl As-Built Diagram F-9 Monitoring Well 13A/B1/MW1 As-Built Diagram '. F-IO Monitoring Well 32/Bl/MWl As-Built Diagram F-l 1 31 -Aug-04 GEOSCIENCE Support Services, Inc. F-i Tetra Tech/San Diego County Water Authority Appendix F Geohydrologic Investigation - Lower San Luis Rey River Valley CONTENTS (Continued) Description Page Monitoring Well D/B2/MW1 As-Built Diagram F-12 Monitoring Well 26/27/Bl/MWl As-Built Diagram F-13 31 -Aug-04 GEOSCIENCE Support Services, Inc. F-ii Tetra Tech/San Diego Couniy Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix F Locking Lid Notes • Borehole diaryieler S'/j" • All measurements are below ground surface in feet • 2-inch diameter 0,020 in. {20-slot) horizontal slot Schedule 40 PVC wei! screen • 2-inch diameter Schedule 40 PVC blank well casing • RMC #2/16 sand filter pack • Well constructed on 14 February. 2002 • Water level measured an 7 May, 2002 LEGEND £253 Concrete Bentonite Chips • Filter Pack § Screen wim Endcap 30'II Venicsi Scslo steel Security Casing, Above Ground Completion (±3 ft.) ^ Concrete Apron n Ground Surface Borehole Diameter —37. 40- 150' San Diego County Water Authority Mission Basin Site I , Piezometer Construction Diagram Figure TBD 31-Aug-04 F-l GEOSCIENCE Support Services, Inc Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rev River Valley Appendix F Locking Lid. Notes - Borehoie diameter 16" • All measurements are beiow ground surface in feet • 4-inch diameter 0.080 in. (80-slot) horizanta! stot Schedule 80 PVC well screen • 4-inch diameter Schedule 80 PVC blank well casing • RMC 4x12 sand filter pack • Well constructed on 13 February, 2002 • Water level measured on 7 May, 2002 15' 30' Vailical Scala LEGEND C2Si3 Concrete Grout L I Filter Pack 1^^^ Screen . Steel Security Casing, Above Ground Completion (+3 ft.) Concrete Apron Ground Surface 7.6 r BGS San Diego County Water Authority Mission Basin Site 1 Monitoring Weft Construction Diasram Figu re TSO 31-Aug-04 F-2 GEOSCIENCE Support Services, Inc 0- t5 20 25 SO- SO 95 100- 150- 158 200- 210 250- 300- TD=310- 305 8 5/8 In. OD 3teel monument protective well cover and concrete pad (see detail) Cement-bentonite seol (0-15 ft) 1/4 in. Bentonite pellet seal (15-20 ft) 2 in. flush threoded Sch. 40 PVC blank cosing (0-25 ft) 2 in. flush threaded Sch. 40 PVC well screen (0.020 in. slot) (25-90 ft) RMC Monterey #3 silica sand (20-100 ft) •2 in. Sch. 40 PVC bianl< casing with end cap (90-95 ft) 1/4 In. Bentonite pellet seal (100-158 ft) |—4 in. X 6 ft Sch. 80 mnd sted post mild stSBl trafric poata set In 8 In. hol« to 3 ft bga. (concrete filled) •2 in. flush threaded Sch, 80 PVC bionk cosing (0-210 ft) PUN VIEW -4 in. X 6 ft Sch. 80 mild steel post (concrete filled} a s/S In. RMC Monterey #3 silica sand (158-310 ft) 10 1/2 in. dio. borehoie (0-310 ft) Locking cover -Concrete well pod Blank casing • Cement— bentor^lta seal 2 in. flush threaded Sch. 80 well screen 0.020 in. slot) 210-300 ft) PROTECTIVE STEEL CASING AND CONCRETE PAD DETAIL •2 in. flush threaded Sch. 80 PVC blank casing with end cop (300-305 ft) WELL CROSS SECTION Figure F-3 JN 93-05 PLP Checked; Approvid: Dale; 3t-AUG-04 TETRA TECH/SAN OIEGO COUNTY WATER AUTHORITY' CONSTRUCTION AND WELLHEAD COMPLETION DETAILS WELL gA/B2/MWl Ge0SCt£J4CE SupDVt Svrvlcei, IncorpoigUa P.O, Bo> 220. Cloremonl. C* 91711 (909)9 7Q-07D7 Fan: (909)920-0103 E-mol! BmallOgsMcienc*—wator.com Tal: Tetra Tech/San Diego County Water Authority GeolivcJrologic Investigation - Lower San Luis Rev River Vallev Appendix F Notes • Borehoie diameter 3'/(" - All measurements are below ground surface in feel • 2-inch diameter 0.010 in. {10-slot) horizontal slot Schedule 40 PVC well screen • 2Hnch diameter Schedule 40 PVC blank well'casing • RIVIC #2/16 sand filter pack • Well constructed on 26 February, 2002 • Water level measured on 7 May, 2002 LEGEND Concrete Bentonite pellets D Filter Pack i Screen with Endcap 30' Vertical Sc3Mi Flush Mounted Emco V\ftieaton Traffic Rated Well Box Concrete Apron Ground Surface 90' 120' Borehole Diameter —3'/."— San Diego County Water Authority Tt Mission Basin Site 2B Piezometer Construction Diagrum Figure TBD 31-Aug-04 .F-4 GEOSCIENCE Support Services, Inc Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix F Locking Lid , Steel Security Casing, Above Ground Completion (+3 ft.) Concrete Apron Ground Surface Notes • Borehole diameter 3V(" • All measurements are below ground surface in feet • 2-inch diameter 0.010 in. (10-sIot) horizontal slot Schedule 40 PVC well screen • 2-inch diameter Schedule 40 PVC biank well casing • RMC #2/16 sand filter pack. • Well constructed on 7 March, 2Q02 • Water levei measured on 7 May, 2002 LEGEND tC7*^ Concrete OTSIttg Bentonite Chips I 1 Filter PacK 1 ~r\ Screen with Endcap 30'I Venice! Scale San Diego County WaterAuthority Mission Basin Site3B Piezometer Construction Diugnini TBD 31-Aug-04 .F-5 GEOSCIENCE Support Services, Inc 0- 50- 100- 150- UO 170 200- 250- 300-305 310 350- 375 400- TD=450- B 5/a in. CD steel monument protective well cover and concrete pad (see detail) Cement-bentonite seal (0-140 ft) 10 1/2 in. dia. borehole (0-450 ft) 2 in. flush threaded Sch. 80 PVC blank cosing (0-170 ft) -2 in. flush threaded Sch. 80 PVC bionk casing (0-400 ft) 1/4 in. Bentonite pellet seal (140-150 ft) •2 in. flush threaded Sch. 80 well screen 0.020 In. slot) 170-300 ft) I 4 In. X 6 ft Sch. 60 mild stael post mild ateel traffic posts s«t In B In. hols to 3 ft bgs. (concrato flllad) • o o o cover c I me f 1 c V ) 1 CO ll c >, o X ° « % o RMC Monterey #3 silica sand (150-310 ft and 375-450 ft) PUN VIEW -4 in. X 6 ft Sch. 80 mild stad post (concrsts flllsd) B S/a In, 2 In. flush threaded Sch. 80 PVC blank casing with end cap (305-310 ft) • 1/4 in, Bentonite pellet seal (310-375 ft) -Locking cover Con era ta wall pad ' Blank casing Com ant-ben toni ta saal PROTECTIVE STEEL CASING AND CONCRETE PAD DETAIL •2 in. flush threaded Sch. 80 well screen (0.020 in. slot) (400-440 ft) •2 in. flush threaded Sch. 80 PVC blank casing with end cap (440-445 ft) WELL CROSS SECTION Figure F-6 Drown: Chackad: Approved: Dote; 31-AUG-04 TETRA TECH/SAN DIEGO COUNTY WATER AUTHORITY CONSTRUCTION AND WELLHEAD COMPLETION DETAILS ffELL 3B/B2/MW3 •QSCIEtjCE GEOSOENCE Support S«r\HcM, IncgtBOtolml P.O. Bon 220, Claremont. CA 91711 (909)920-0707 fax: (909)920-0*03 f-mail: DmanOgEaiciflncd-water.com Telra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rev River Vallev Appendix F Flush Mounted EmcQ Wheaton Traffic Rated Weli Box , Concrete Apron Ground Sur^ce Notes • Boretiole diameter 3V,' • All measurements are below ground surface in feet • 2-incti diameter 0,010 in. (IQ-slot) horizontal slot Scinedule 40 PVC well screen - 2-incti diameter Sctiedule 40 PVC blank well casing - RMC #2/16 sand filter pack • Weil constructed on 21 March. 2002 • Water level measured on 7 May, 2002 15'i 30'I Vertical Scjjlo LEGEND t;C2SI3 Concrete Bentonite Chips Filter Pack Screen -,2- X : 20.65'BGS 120' Boretiole Diameter —Z'W— 150' 170' San Diego County WaterAuthority Mission Basin Site 7A Piazomctcr Construction Diagram Figure TBD 31-Aug-04 F-7 GEOSCIENCE Support Services, Inc Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rev River Vallev Appendix F Nates • Boretiole diameter 3'/," ' At! measurements are befow ground surface In feet • 2-incti diameter 0.010 in, (1D-slot) tiorizontal slot Schedu!e 40 PVC well screen - 2-inch diameter Schedule 40 PVC blank well casing ' RMC #2/16 sand filter pack • Well constructed on 18 March, 2002 • V^ter level measured on 7 May, 2002 15' 30'D LEGEND • Concrete Bentonite Chips niter Pack Screen Flush Mounted Emco Wheaton Traffic Ratad Well Box Concrete Apron Ground Surface X 16.61'BGS 130' .! 170' j. 190' Borehole ; Diameter i —-z'/;—^ San Diego County cj- "Water Authority il*^ iVIission Basin Site lOA Piezometer Construction Diagram Figure TBD 31-Aug-04 .F-8 GEOSCIENCE Support Services, Inc 0- 50- 100- 150- 162 169 180 200- 250-255 260 2B9 300- 350- 400- TD=420-m 8 5/8 in. OD steel monument protective well cover and concrete pod (see detail) Cement-bentonite seoi (0-162 ft) 10 1/2 In. dia. borehoie (0-420 ft) 2 In. Sch. 80 PVC blank casing (0-180 ft) -4 In. K 6 ft Sch. 80 mild atsel post mild atasl traffic poata aat In 6 In. hol« to 3 ft bgs. (concrete filled) •2 In. flush ttireaded Sch. 80 PVC blank cosing (0-300 ft) 1/4 in. Bentonite pellet seol (162-169 ft) 2 In. Sch. 80 PVC well screen 0.020 in. slot) 180-250 ft) RMC Monterey #3 silica sand (169-260 ft) o o o 8 G ( ) 1 V J E • JO lO . nJ » _ o •o s & o PLAN VIEW -* In. X 6 ft Sch. 80 mild ated post (concrete filled) Locking cover • 2 in. Sch. 80 PVC blank casing with threaded end cop (250-255 ft) • 1/4 in. Bentonite pellet seal (260-289 ft) RMC Monterey #3 silica sand (289-420 ft) Bionk casing Com wit— bentonlto soal •2 in. flush threoded Sch. 80 well screen (0.020 in. slot) (300-410 ft) 2 in. flush threoded Sch. 80 PVC blank casing with end cap (410-415 ft) PROTECTIVE STEEL CASING AND CONCRETE PAD DETAIL WELL CROSS SECTION Figure F-9 PLP Checked; ApprcvBd; Data: TETRA TECH/5AN OlECD COUNTY WATER AUTHORITY CONSTRUCTION AND WELLHEAD COMPLETION DETAILS WELL UC/Bl/Mffl G^SCIENCE CEOSaENCE Support SonHcoii InctuporQtid P.O. eo> 220, doTdnwil. C* 91711 el: (909)920-0707 fm: (809)820-0403 E-mail: Bmol^eo^cJfinct-^-ntor.con- Tetra Tech/Sah Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rev River Vallev Appendix F locking Lid, Notes - Borehole diameter 3'/," • All measurements are from below the ground surfece in feet. • 0.020 in. (20-sIot) type 304 (SCH.40) stainless steel extra strength wire wrapped screen. • 4-inch diameter Schedule 80 PVC blank well casing. • #3 sand filter pack. • Well constructed on 13 February, 2002 • Water level measured on 7 May, 2002 LEGEND [;2S3 Concrete I 1 Filler Pack liznnzi Screen with Endcap ID' Vonteal Scalo i , Steel Secuhty Casing, Above Ground Completion (+3 fi.) Concrete Apnsn Ground Surface I',,.... 2.69'BGS 3 25' 30' Boretiole Diameter —3'/,' San Diego County Water Authority Mission Basin Site 13A Piezometer Construction Diagram yigure TBD 31 -Aug-04 F-10 GEOSCIENCE Support Services, Inc Tetra Tech/San Diego County Water Authority Geohydroiogic Investigation - Lower San Luis Rev River Vallev Appendix F Locking Lid Notes * Borehole diameter 37," * Ai! measurements are from below the ground surface in feet. ' 0,020 in, (20-siot) type 304 {SCH.40) stainless steel extra strength wire wrapped screen. • 4-inch diameter Schedule 80 PVC blank well casing. • #3 sand filter pack, • Well Constructed on 5 March, 2002 * Water ievel measured on 7 May, 2002 15' 30-1 Vedical SooiB LEGEND IsJ^SS Concrete Bentonite Chips 3 Filter Pack Screen with Endcap -5^ m Stee! Security Casing, Above Ground Completion (+3 ft) Concrete Apron Ground Surface Borehole Diameter —3V; •3' 9.49' BGS 160' 180' 210" San Diego County WaterAuthority Mission Basin Site 32 Piezometer Construction Diagr;ini TBD 31-Aug-04 GEOSCIENCE Suppoit Services, Inc .F-11 0- 50- 62 85 100- 150- 140 145 155 171 190 S. 200- 250- 300- 270 275 305 i 350- 400- TD=422- • 8 5/8 in. OD steei monument protective well cover and concrete pad (see detail) 10 1/2 in. dia. borehole (0-305 ft) Cement-bentonite seal (0-50 ft) 1/4 In. Bentonite pellet seal (50-62 ft) 2 in. flush threaded Sch. 40 PVC blank casing (0-85 ft) 2 in. Sch. 40 PVC weli screen (0.020 in. slot) (85-140 ft) •2 In. Sch. 40 PVC blanl< casing with threoded end cop (140-145 ft) • 1/4 in. Bentonite pellet seol (155-171 ft) 2 in. flush threaded Sch. 80 PVC blank cosing (0-190 ft) • RMC Monterey #3 silica sand (62-155 ft and 171-305 ft) •2 in. flush threaded Sch. 80 well screen (0.020 in. slot) (190-270 ft) • 2' in. flush threaded Sch. 80 PVC bionk casing with end cop (270-275 ft) I 4 in. ¥ 6 ft Sch. 80 mild Bt«9l post mild Btael traffic poata sot In S In. hols to 3 ft bgs. (concrsts flllsd) PLAN VIEW -4 In. X 6 ft Sch. 80 mild atsel poat (concrsts flllsd) 0 9/B In. -Locking cover r Concrsts wsll pad Blank cosing • Csmsnt- bsntcnlte seal 5 in. dio. pilot bore hole bockfill with native (to 422 ft) PROTECTIVE STEEL CASING AND CONCRETE PAD DETAIL WELL CROSS SECTION Figure F-12 Drawn; Chackad: Approvid: Dais: TETRA TECH/SAN OIEGO COUNTY WATER AUTHORITY CONSTRUCTION AND WELLHEAD COMPLETION DETAILS ffEU D/B2/Mffl GEOSCIENCE GCQSOENCE Suppe't Sarv^cai. tncorporalsi) P.O. Bs> Z:0, Clargrnont, CA 91711 el: (aO9)8Z0-O7O7 for. (909)8 20-0»O3 E-mol: omailOiJOMtienci-mtB-.com 0- 20- 40- 60- 50 55 62 70 SO- BS 100- 110 115 TD=120- 1^ <1 • 8 5/8 in. OD steei flush mounted protective well cover and concrete pod (see detail) Cement-bentonite seal (0-10 ft) 1/4 In. Bentonite pellet seal (10-15 ft) 2 in. flush threaded Sch. 40 PVC blank casing (0-20 ft) 2 in. flush threaded Sch. 40 PVC well screen (0.020 in. slot) (20-50 ft) RMC Monterey #3 silico sand (15-62 ft) 2 in. flush threaded Sch. 40 PVC blank casfng with end cop (50-55 ft) 1/4 In, Bentonite pellet seal (62-70 ft) RMC Monterey #3 silica sand (70-120 ft) \ 8 c \ V £ \) 1. mor CO 6 » D •O » PUN VIEW 12 in. T _:' -10 1/2 in. dia. borehole (0-120 ft) •2 in. flush threaded Sch. 40 well screen (0.020 !n. slot) (85-110 ft) 'mm- -(2) 2 In. sxpandcble prsssurs pluga -(2) 2 In. Sch. 40 PVC blank casings FLUSH-MOUNTED PROTECTIVE VAULT AND COVER 2 in. flush threaded Sch. 40 PVC blank cosing with end ca (110-115 ;ap ft) WELL CROSS SECTION Figure F-13 JN 93-03 Chflcked: Approved; Date: 31-AUG-04 TETRA TECH/SAN OIEGO COUNTY WATER AUTHORITY CONSTRUCTION AND WELLHEAD COMPLETION DETAILS WELL 26/27/Bl/Mffl GEOSCIENCE Support S<n4ca>, Incurparutsd P.O, Bo« 220, ClorKTionl. CA 01711 m: (909)920-0707 Fox: [909)920- 0*03 E-moi: BmaJI0g«04CiflncB^watv,com APPENDIX G Well Completion Details - Site 1 Test Well 1C/TW1 GEOSCIENCE Support Services. Inc. Tetra Tech/San Diego County Water Authorily Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix G Locking Lid Notes • Borehole diameter 16" - All measurements are below ground surface in feet • 6-inch diameter 0.080 in. (80-siot) type 304 (SCH.40) stainless steel extra strength wire wrapped screen - 6-inch diameter Schedule 80 PVC blank welt casing • RMC 4x12 sand filter pack • Well constructed on 4 February, 2002 • Water level measured on 7 May, 2002 IS' 30' vcnreal Stale LEGEND Concrefe E^gS3 Cement Grout r I Filter Pack Wire Wrapped Screen Steel Security Casing, Above Ground Completion (±3 ff.) Concrete Apron Ground Surface 7.72- ees 22t3- 22Q- i Bofefiole i Diameter ,6 »- San Diego County WaterAuthority Mission Basin Site t Test Wctl Construction Diagram Figure TBD 31-Aug-04 GEOSCIENCE Support Services, Inc, G-1 APPENDIX H Pumping Test Data GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily Appendix H Geohydrologic fnvestigation - Lower San Luis Rey River Valley APPENDIX H PUMPING TEST DATA CONTENTS Description Page Constant Rate Test Data - ] C/TW-1 H-1 Step Drawdown Test Data - D/TW 1/PW9 H-4 24-Hour Constant Rate Test Data - D/TW1/PW9 H-6 D/B2/MW1-S (Observation Well) - 24-Hour Constant Rate Pumping Test H-24 D/B2/MW1-D (Observation Well)- 24-Hour Constant Rate Pumping Test H-25 OW-11 (Observation Well) - 24-Hour Constant Rale Pumping Test H-26 OW-1 (40 East) (Observation Well) - 24-Hour Constant Rate Pumping Test H-27 OW-2 (J 40 West) (Observation Well) - 24-Hour Constant Rate Pumping Test H-28 OW-1 Shallow (Observation Well) - 24-Hour Constant Rate Pumping Test H-29 PW-1 (Observation Well) - 24-Hour Constant Rate Pumping Test H-30 PW-2 (Observation Well) - 24-Hour Constant Rate Pumping Test H-31 31 -Aug-04 GEOSCIENCE Support Services, Inc, H-i Tetra Tcch/San Diego County Water Authority Appendix H Geohydrologic Investigation - Lower San Luis Rey River Valley CONTENTS (Continued) Description Page 2A/B2/MW1-S (Observation Well) - 24-Hour Constant Rate Pumping Test H-32 2A/B2/MW1-D (Observation Well) - 24-Hour Constant Rate Pumping Test H-33 2B/B1/MW1 (Observation Well) - 24-Hour Constant Rate Pumping Test H-34 3B/B1/MW1 (Observation Well) - 24-Hour Constant Rate Pumping Test H-35 3B/B2/MW2-S (Observation Well) - 24-Hour Constant Rate Pumping Test H-36 3B/B2/MW2-D (Observation Well) - 40-Hour Constant Rate Pumping Test H-37 32/Bl/MWl (Observation Well) - 24-Hour Constant Rate Pumping Test H-38 D/TW1/PW9 (Puinpirig Well) - 24-Hour Constant Rate Pumping Test - Jacob's Straight Line Applied to Recovery H-39 D/B2/MW1-S (Observation Well) - 24-Hour Constant Rate Pumping Test - Jacob's Straight Line Applied to Recovery H-40 D/B2/MW1-D (Observation Well) - 24-Hour Constant Rate Pumping Test - Jacob's Straight Line Applied to Recovery H-41 31-Aug-04 GEOSCIENCE Support Services, Inc, H-ii Tetra Tech/San Diego County Water Authority AppCndiX H Geohydrologic Investigation - Lower San Luis Rey River Valley CONTENTS (Continued) Description Page OW-2 (140 West) (Observation Well) - 24-Hour Constant Rate Pumping Test - Jacob's Straight Line Applied to Recovery H-42 2B/B1/MW1 (Observation Well) - 24-Hour Constant Rate Pumping Test - Calculated Recovery H-43 PW-3 (Pumping Well) - 40-Hour Constant Rate Pumping Test Data H-44 OW-1 (40 East) (Observation Well) - 40-Hour Constant Rate Pumping Test H-57 OW-1 (Shallow) (Observation Well) - 40-Hour Constant Rate Pumping Test H-58 PW-2 (Observation Well) - 40-Hour Constant Rate Pumping Test H-59 PW-3 (Observation Well) - 40-Hour Constant Rate Pumping Test H-60 2B/ MWl (Observation Well) - 40-Hour Constant Rate Pumping Test H-61 2A/B2/MW1-S (Observation Well) - 40-Hour Constant Rate Pumping Test H-62 2A/B2/MW1-D (Observation Well) - 40-Hour Constant Rate Pumping Test H-63 3B/B2/MW2-S (Observation Well) - 40-Hour Constant Rate Pumping Test H-64 31 -Aug-04 GEOSCIENCE Support Services, Inc. H-iii Tetra Tech/San Diego County Water Authority Appendix H Geohydrologic Investigation - Lower San Luis Rey River Valley CONTENTS (Continued) Description Page 3B/B2/MW2-D (Observation Well) - 40-Hour Constant Rate Pumping Test H-65 1 IC/Bl/MWl-S (Observation Well) - 40-Hour Constant Rate Pumping Test H-66 11C/B1 /MW1 -D (Observation Well) - 40-Hour Constant Rate Pumping Test H-67 PW-2 (Observation Well) - 40-Hour Constant Rate Pumping Test - Calculated Recovery.... H-68 PW-3 (Pumping Well) - 40-Hour Constant Rate Pumping Test - Jacob's Straight Line Applied to Recovery H-69 31-Aug-04 GEOSCIENCE Support Services, Inc. H-iv APPENDIX H Pumping Test Data Constant Rate Test Data - 1C/TW1 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Suppoit Services, Inc. Ground Waler Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 25-Feb"02 Well Natne/Number: lC/TW-1 Circle Well Type: Circle Test Type: Observation (r = ft) Step Drawdown C^onstant Rate^]!^ Recovery Development pth: 9.91 ft below RP Reference Point Elevation: + 0.00 ft Time of Day Time Step [min] Time Total [min] Depth to Water [ft] Draw- down [ft] Pumping Rate ISPm] Sand Content [ppm] Totalizer X 100 [^al] Remarks and Other Data 10:30 AM -0 9.91 0 50 --Pump On 11:36 AM -63 10.79 0.88 50 -- 1:00 PM -150' 11.02 1.11 50 -- 2:27 PM -237 11.20 1,29 50 -- 3:33 PM -303 11.27 1.36 50 -- 3:35 PM -305 10.68 0.77 50 -- 3:36 PM -306 10.66 0.75 50 -- 3:38 PM -308 10.70 0,79 50 -- 3:51 PM -321 10.59 0.68 50 -- 4:03 PM -333 10.54 0.63 50 --Pump Off 31-Aug-04 H-1 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix IH GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 25-Feb-02 Well Name/Number: lA/MW-1 Circle Well Type: Circle Test Type: Pumping Step Drawdown Observatioal^ (r = 23.5 ft) pnstant Rate^ Recovery Development Static Water Level Depth: 12.41 ft beiow RP Reference Point Elevation: 2.00 ft Time of Day Time Step [min] Time Total [min] Depth to Water [ftl Draw- down [ft] Pumping Rate [fipml Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 10:30 AM -0 12.41 0 50 Pump On 10:42 AM -12 12.56 0.15 50 - 11:05 AM -35 12.66 0.25 50 -- 11:30 AM -60 12,74 0.33 50 -- 12:00 PM -90 12,83 0.42 50 -- 12:42 PM -132 12,93 0,52 50 -- 1 30 PM -180 13,04 0,63 50 -- 1 50 PM -200 13.09 0,68 50 -- 3 01 PM -271 10.68 0.86 50 -- 3 27 PM -297 13.27 0.86 50 -- . 31-Aug-04 H-2 GEOSCIENCE Support Services, Inc. Tetra Tecli/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 25-Feb-02 Well Name/Number: lB/MW-2 Circle Well Type: Circle Test Type: Static Water Level Pumping Step Drawdown Depth: 9.82 ft below RP X'bservationJ^ (r = 10 ft) Constant RateJ^ Recovery Development Reference Point Elevation: + 2.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 10:30 AM -0 9,82 0 50 -Pump On 10:31 AM -1 9,91 0,09 50 -- 10:32 AM 2 9.92 0.10 50 -- 10:33 AM -3 9,94 0.12 50 -- 10:34 AM -4 9.95 0.13 50 -- 10:35 AM -5 9-96 0.14 50 -- 10:37 AM -7 9.98 0,16 50 -- 10:40 AM -10 10.00 0,18 50 -- 10:48 AM -18 10.04 0,22 50 -- 10:55 AM -25 10.07 0,25 50 -- 11:00 AM -30 10.09 0.27 50 - 11:25 AM -55 10,18 0.36 50 -- 11:45 AM -75 10,23 0.41 50 -- 11:58 AM -88 10,27 0.45 50 -- 12:36 PM -126 10,38 0,56 50 -- 12:55 PM -145 10,42 0.60 50 -- 1:25 PM -175 10,48 0,66 50 -- 1:55 PM -205 10,55 0,73 50 -- 2:20 PM -230 10,61 0,79 50 -- 3:01 PM -271 10.68 0,86 50 -- 3:30 PM -300 10.73 0.91 50 -- 3:37 PM -307 10.62 0.80 50 -- 3:46 PM -316 10.58 0,76 50 --Pump Off 4:08 PM -338 10.54 0.72 50 -- 31-Aug-04 H-3 GEOSCIENCE Support Services, Inc. APPENDIX H Pumping Test Data Step Drawdown Test Data - D/TW1/PW9 GEOSCIENCE Support Services. Inc. Tetra Tcch/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support S ervices, Inc, Ground Water Resources Development PUMPING TEST DATA TEL: (909)920-0707 FAX: (909) 920-0403 Test Date: 16-Feb-04 Well Name/Number: Desalter Test Well D/TW1/PW9 Circle Well Type: CPumpin£) Observation (r = ft) Circle Test Type: C^tep Drawdo^n]^ Constant Rate Recovery Development Static Water Level Depth: 14.29 ft below RP Reference Point Elevation: + 1.96 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 10:06 AM 0 0 14.21 -0 -49635 Stan pump. 10:18 AM 12 12 31.40 17.11 1,312 49792 10:21 AM 15 15 31.68 17.39 1,366 49833 10:26 AM 20 . 20 32.00 17.71 1,220 49894 i0:31 AM 25 25 32.15 17.86 1,260 49957 10:36 AM 30 30 32.29 18,00 900 50002 10:46 AM 40 40 32.50 18.21 1,000 50102 10:56 AM 50 50 32.66 18.37 1,060 50208 11:11 AM 65 65 32.83 18,54 1,010 50309 Ql = 1,124 gpm; SC, = 54 gpm/ft 11:13 AM 2 67 41.57 27,28 2,300 50355 11:15 AM 4 69 41.92 27.63 1,250 50380 11:17 AM 6 71 42.06 27.77 1,600 50412 11:19 AM 8 73 42.21 27.92 900 50430 11:21 AM 10 75 42.28 27.99 1,700 , 50464 11:26 AM 15 80 42.46 28.17 1,860 50557 11:31 AM 20 85 42.63 28.34 960 50605 11:36 AM 25 90 42.78 28.49 1700 50690 11:41 AM 30 95 42.90 28,61 1600 50770 11:51 AM 40 105 43,08 28.79 1600 50923 12:01 PM 50 115 43.20 28.91 1630 51086 12:11 PM 60 125 43.35 29.06 1490 51235 12:21 PM 70 J35 43.46 29.17 1600 51395 12:31 PM . 80 145 43.55 29.26 1520 51547 12:41 PM 90 155 43.64 29,35 1620 51709 12:51 PM 100 165 43,77 29.48 1400 51849 1:01 PM UO 175 43.80 29.51 1510 52000 1:10 PM 119 184 43.85 29,56 1600 52160 Q2 ^ 1,542 gpm, SC2 = 54 gpm/ft 1:12PM 2 186 53.07 38,78 2850 52217 1:14PM 4 188 53.25 38.96 1900 52255 1:16PM 6 190 53.40 39.11' 2350 52302 1:18PM 8 192 53,54 39.25 2400 52350 1:20 PM 10 194 53.60 39.31 1250 52375 1:25 PM 15 199 53.75 39.46 2200 52485 1:30 PM 20 204 53.84 39.55 -2100 52590 31-Aug-04 H-4 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development PUMPING TEST DATA icL,: i,yuy^ yzo-o/o/ FAX: (909) 920-0403 Test Dale: 16-Feb-04 Well Name/Number: Desalter Test Weil D/TW1/PW9 Circle Wei! Type: CPumpin_£!) Observation (r = ft) Circle Test Type: C^tpp Drawdown!!!^ Constant Rate Recovery Development Static Water Level Depth: 14.29 ft below RP Reference Point Elevation: + 1.96 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total . Water down Rate Content Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 1:35 PM 25 209 53.95 39.66 1920 52686 1:40 PM 30 214 54.07 39.78 1760 52774 , 1:50 PM 40 224 54.59 40.30 1360 52910 2:00 PM 50 234 54.74 40.45 2750 53185 2:10PM 60 244 54,86 40.57 2230 53408 2:20 PM 70 254 54.89 40.60 1920 53600 2:30 PM 80 264 55.04 40.75 1880 53788 2:40 PM 90 274 55,13 40.84 2180 54006 2:50 PM 100 284 55,21 40.92 2110 54237 3:00 PM 110 294 55.28 40,99 1810 54398 3:10PM 120 304 55.32 41,03 2300 54628 3:20 PM 130 314 55,43 41.14 1820 54810 3:30 PM 140 324 55,45 41,16 1930 55003 3:40 PM 150 334 55.75 41,46 2170 55220 3:50 PM 160 344 55.84 41,55 2000 55420 4:00 PM 170 354 55.85 41.56 1960 55616 4:10 PM 180 364 55.91 41,62 2700 55886 Q3 = 2,070 gpm; SC3 = 65 gpm/ft 31-Aug-04 H-5 GEOSCIENCE Support Services, Inc. APPENDIX H Pumping Test Data Constant Rate Test Data - D/TW1/PW9 GEOSCIENCE Support Sen'ices, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: Desalter Test Well D/TW1/PW9 Circle Well Type: C^mpin^ Observation (r- ft) Circle Test Type: Step Drawdown c^onstanl Rate^ Recovery Static Water Level Depth: 13.94 ft below RP Reference Point Elevation: + 1 Development ,96 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content X 100 Remarks and Other Data Day [inin] [min] [ft] [ft] [gpm] [ppm] [gal] 7:59 AM -0 13.94 0.00 -55885 Pump On 8:01 AM -2 44.48 30.54 2650 trace 55938 8:03 AM -4 46.51 32,57 2750 55995 8:05 AM -6 45.38 31,44 2333 56025 8:07 AM -8 45.82 31.88 2138 56056 8:09 AM -10 46.17 32.23 2450 56130 8:14 AM -15 46.80 32.86 1900 56170 8:19 AM -20 47.54 33.60 2025 56290 Ave. Q = 2,025 gpm 8:24 AM -25 47.86 33.92 2076 56404 Adjust Q (Decrease) 8:29 AM -30 48.16 34.22 1883 56450 • 8:39 AM -40 48.56 34.62 1913 56650 8:49 AM -50 48.82 34.88 1884 56827 8:59 AM -60 49.06 35,12 1883 57015 Ave, Q= 1,825 gpm 9:14 AM -75 49,35 35,41 1887 57300 9:29 AM -90 49,61 35,67 1872 57570 9:44 AM -105 49,80 35.86 1875 57854 9:59 AM -120 49,96 36.02 1871 58130 10:14 AM -135 50.11 36.17 1870 58410 10:29 AM -150 50.28 36,34 1837 58640 10:44 AM -165 50,43 36,49 1858 58950 10:59 AM -180 50,48 36.54 1864 59240 11:29 AM -210 50.64 36.70 1860 59790 11:59 AM -240 50.88 36,94 1860 60350 12:29 PM -270 50.95 37.01 1857 60900 12:59 PM -300 51,09 37,15 1853 61445 1:29 PM -330 51,19 37.25 1853 61999 1:59 PM -360 51,30 37,36 1851 62550 Ave.Q^ 1,845 gpm 2:29 PM -390 51,37 37.43 1847 63090 2:59 PM -420 51.46 37,52 1849 63650 3:29 PM -450 51,59 37,65 1847 64198 3:59 PM -480 51,67 37.73 1849 64760 4:59 PM -540 51.79 37.85 1849 65870 5:59 PM -600 51,87 37.93 1847 66968 6:59 PM -660 51.98 38,04 1847 68075 Ave, Q= 1.842 gpm 3I-Aug-04 H-6 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: Desalter Test Well D/TW1/PW9 Circle Well Type: Circle Test Type: ^mpmj Step Drawdown Observation (r = ft) "Constant Rate^ Recovery Development Static Water Level Depth: 13.94 ft below RP Reference Point Elevation: -i- 1 96 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 8:59 PM -780 52.23 38.29 1844 70270 9:59 PM -840 52.27 38.33 1847 71400 10:59 PM -900 52.30 38,36 1843 72470 Adjust Q (Increase) 11:59 PM -960 53.82 39,88 1851 73650 12:59 AM -1020 53.85 39,91 1854 74800 1:59 AM -1080 53.95 .40,01 1855 75915 2:59 AM -1140 53.99 40,05 1871 77217' 3:59 AM -1200 54.04 40,10 1863 78240 4:59 AM -1260 54,08 40.14 1866 79400 Ave, Q= 1,887 gpm 5:59 AM -1320 54,08 40.14 1865 80500 6:59 AM -1380 54,11 40.17 1868 81660 7:59 AM -1440 79,59 65.65 1871 82825 8:24 AM -1465 79.61 65.67 1879 S34I9 Q= J,850 gpm (test ave) 8:33 AM -1474 24.71 10.77 ---Pump off 18-Feb-04 8:43 AM -1484 20.25 6.31 --- 8:53 AM -1494 19.28 5,34 --- 9:03 AM -1504 18.71 • 4.77 -- 9:13 AM -1514 18.30 4.36 --- 9:23 AM -1524 17.98 4.04 --- 9:33 AM -1534 17.71 3.77 --- 9:43 AM -1544 17,48 3.54 --- 9:53 AM -1554 17,28 3.34 --- 10:03 AM -1564 17,11 3.17 --- 10:13 AM -1574 16,95 3,01 --- 10:23 AM -1584 16.81 2,87 --- 10:33 AM -1594-16.68 2,74 --- 10:43 AM -1604 16.56 2,62 --- 10:53 AM -1614 16.44 2,50 --- 11:03 AM -1624 16.34 2,40 --- 11:13 AM -1634 16.24 2.30 --- 11:23 AM -1644 16,14 2.20 --- 11:33 AM -1654 16,06 2.12 --- 11:43 AM -1664 15,98 2,04 --- 12:00 PM -1681 15,85 ' 1,91 ---End recovery 31-Aug-04 H-7 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Suppoit Services, Inc. Ground Water Re-iources Development TEL: (909)920-0707 , FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: Well D/B2/MW2-S Circle Well Type: Pumping C5bservatioivj>^ 50 ft) Circle Test Type: Step Drawdown C^onstant ^te^ Recovery Development Static Water Level Depth: 13,88 ft below RP Reference Point Elevation: -i- 1.93 fl Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rale Conlenl X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 8:00 AM 0,00 13,88 0,00 Pump on 9:00 AM 60 23.89 10,01 10:00 AM 120 24.83 10,95 11:00 AM 180 25.36 11,48 12:00 PM 240 25.73 11.85 1:00 PM 300 25.99 12,11 2:00 PM 360 26.19 12.31 3:00 PM 420 26.36 12.48 4:00 PM 480 26.52 12.64 5:00 PM 540 26.64 12.76 6:00 PM 600 26.75 12,87 7:00 PM 660 26,85 12,97 8:00 PM 720 26,94 13.06 9:00 PM 780 27.01 13.13 10:00 PM 840 27,07 13.19 11:00 PM 900 27.12 13.24 12:00 AM 960 27.52 13,64 1:00 AM 1020 27.58 13,70 2:00 AM 1080 27,64 13.76 3:00 AM 1140 27.67 13.79 4:00 AM 1200 27,72 13.84 5:00 AM 1260 27,75 13.87 6:00 AM 1320 27,78 13.90 7:00 AM 1380 27.80 13.92 8:00 AM 1440 27.83 13.95 9:00 AM 1500 18.68 4.80 Pump off 10:00 AM 1560 17.03 3.15 11:00 AM 1620 16,26 2.38 12:00 PM 1680 15.75 1.87 1:00 PM 1740 15,37 1,49 31-Aug-04 H-8 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development PUMPING TEST DATA TEL: (909)920-0707 FAX: (909) 920-0403 Test Date: 17 & 18 Feb-04 Well Name/Number: Well D/B2/MW1-D Circle Weli Type: Pumping < 'Observation7&= 50 ft) Circle Test Type: Step Drawdown ^^nslant RaieJ]!^ Recovery Development Static Waler Level Depth: 15.31 ft beiow RP Reference Point Elevation: + 1,92 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Tolal Waler down Rate Content X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 8:00 AM 0.00 15.31 0.00 Pump on 9:00 AM 60 30.96 15.65 10:00 AM 120 34,67 19.36 11:00 AM 180 36,64 21.33 12:00 PM 240 37,94 22.63 1:00 PM 300 38.88 23,57 2:00 PM 360 39.60 24,29 3:00 PM 420 40.18 24,87 4:00 PM 480 40.69 25,38 5:00 PM 540 41.10 25.79 6:00 PM 600 41.45 26.14 7:00 PM 660 41.76 26.45 8:00 PM 720 42.04 26,73 9:00 PM 780 42.28 26,97 10:00 PM 840 42,49 27.18 11:00 PM 900 42,68 27,37 12:00 AM 960 43,47 28,16 1:00 AM 1020 43.76 28,45 2:00 AM 1080 43.97 28,66 3:00 AM 1140 44.13 28,82 4:00 AM 1200 44,29 28.98 5:00 AM 1260 44,42 29.11 6:00 AM 1320 44,54 29.23 7:00 AM 1380 44.64 29,33 8:00 AM 1440 44.75 29,44 9:00 AM 1500 33.27 17,96 Pump off 10:00 AM 1560 26,42 11,11 11:00 AM 1620 23,66 8,35 12:00 PM 1680 22.01 6,70 1:00 PM 1740 20.84 5.53 31-Aug-04 H-9 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation • Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & l8-Feb-04 Well Name/Number: Well OW-11 Circle Well Type: Circle Test Type: Pumping Step Drawdown :^servatio"iT>= 260 ft) Constant Rate^ Recovery Development Static Water Level Depth: 22,72 ft below RP Reference Poinl Elevation: -i- 0.00 ft Time of Day Time Step [min] Time Tolal [min] Depth to Water [ft] Draw- down [ft] Pumping Rale [gpm] Sand Conlenl [ppm] Totalizer X 100 [gal] Remarks and Other Data 9:20 AM 19.79 -2.93 Pump on 10:36 AM 20,79 -1.93 11:53 AM 21.76 -0.96 1:39 PM 22.94 0.22 3:19 PM 23.87 1.15 5:12 PM 24,71 1.99 6:30 PM 25,18 2.46 7:42 PM 25,57 2.85 9:28 PM 26,05 3.33 11:25 PM 26.55 3.83 1:43 AM 27.04 4.32 5:55 AM 27.67 4.95 9:38 AM 27.85 5.13 Pump off 11:10AM 26,42 3.70 1:07 PM 24,74 2.02 31-Aug-04 H- 10 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Waler Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Dale: 17 & 18-Feb-04 Well Name/Number: Well OW-1 (40 East) Circle Well Tvoe: Pumpine <rObservalio'n> = 290 ft) Circle Test Type: Step Drawdown <^onstanl Rate]^ Recovery Development Static Water Level Depth: 17.91 ft below RP Reference Point Elevation: + 0,00 ft Time of - Day Time Step [min] Time Total [min] Depth to Water [ft] Draw- down [ft] Pumping • Rale [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remark.s and Other Data 9:16 AM 17,82 -0,09 Pump on 10:32 AM 17.79 -0,12 11:50 AM 17.74 -0,17 1:36 PM 17.72 -0,19 3:12 PM 17.71 -0.20 5:08 PM 17,71 -0.20 6:38 PM 17.71 -0.20 8:31 PM 17.73 -0,18 10:04 PM 17,71 -0.20 12:47 AM 17,67 -0.24 3:41 AM 17,67 -0.24 9:04 AM 17.75 -0.16 Pump off 11:27 AM 17.65 -0,26 1:28 PM 17.52 -0.39 31-Aug-04 H- 1 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: Well OW-2 (140 West) Circle Well Type: Pumping CObservationJi" = 290 ft) Circle Test Type: Step Drawdown C^onslant Rale^^ Recovery Development Static Water Level Depth: 15.84 ft below RP Reference Point Elevation: -i- 0,00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rale Content X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 8:00 AM 15,55 -0.29 , Pump on 9:00 AM 20,27 4.43 10:00 AM 21,20 5.36 11:00 AM 21.71 5.87 12:00 PM 22.06 6.22 1:00 PM 22.31 6.47 2:00 PM 22.50 6.66 3:00 PM 22.65 6.81 4:00 PM 22.79 6.95 5:00 PM 22,91 7.07 6:00 PM 23,01 7.17 7:00 PM 23,10 7.26 8:00 PM 23.18 7,34 9:00 PM 23.24 7,40 10:00 PM 23.30 7,46 11:00 PM 23.35 7.51 12:00 AM 23.55 7.71 1:00 AM 23.61 7.77 2:00 AM 23.66 7.82 3:00 AM 23.69 7.85 4:00 AM 23.73 7.89 5:00 AM 23.78 7.94 6:00 AM 23,79 7.95 7:00 AM 23,81 7.97 8:00 AM 23,84 8.00 9:00 AM 20,01 4.17 Pump off 10:00 AM 18,48 2.64 11:00 AM 17.77 1,93 12:00 PM 17.29 1,45 1:00 PM 16.93 1,09 31-Aug-04 H- 12 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey Rivcr Valley Appendix H GEOSCIENCE Support Services, Inc, Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: Well PW-3 Circle Well Type: Circle Test Type: Static Water Level Pumping Step Drawdown Depth: 18,72 ft below RP ;qbservaiionJi-= 390 fl) ^stanl Ratejl!> Recovery Development Reference Poinl Elevation: -i- 2.00 fl Time of Day Time Step [min] Time Tolal [inin] Depth lo Waler [ft] Draw- down [ft] Pumping Rale [gpm] Sand Conlenl [ppm] Totalizer X 100 [sal] Remarks and Other Data 9:22 AM 18,72 0.00 Pump on 3:22 PM 24,83 6.11 7:20 AM 18,46 -0.26 9:05 AM 22.39 3.67 10:21 AM 23.40 4.68 11:38 AM 23.94 5.22 1:15 PM 24.35 5.63 3:01 PM 24,66 5.94 4:58 PM 24,88 6.16 < 6:50 PM 25,04 6.32 8:44 PM 25,17 6,45 10:22 PM 25,26 6,54 12:58 AM 25.56 6,84 3:53 AM 25.64 6,92 8:50 AM 23.31 4.59 Pump off 11:18 AM 20.42 1,70 i :10 PM 19.70 0.98 31-Aug-04 H- 13 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Dale: 17 & 18-Feb-04 Well Name/Number: Well PW-2 Circle Well Type: Pumping CpbservalionX^ = 565 - fl) Circle Test Type: Step Drawdown Constant Rale]]]^ Recovery Development Sialic Waler Level Depth: 19.19 ft below RP Reference Poinl Elevation: + 2 OOft Time of Day Time Step [min] Time Tolal [min] Depth lo Waler [ft] Draw- down [ft] Pumping Rate [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 9:15 AM 19.19 0.00 Pump on 3:25 PM 23.72 4.53 7:22 AM 18,92 -0.27 9:08 AM 21,57 2,38 10:24 AM 22,47 3,28 11:41 AM 22.97 3,78 1:19 PM 23.33 4.14 3:04 PM 23.61 4.42 5:01 PM 23.84 4.65 6:49 PM 23.92 4.73 8:38 PM 24,13. 4.94 10:08 PM 24,22 5.03 12:53 AM 24.42 5.23 3:46 AM 24.53 5.34 8:58 AM 23.12 3.93 Pump off 1:17 PM 20,05 0.86 31-Aug-04 H-T4 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development PUMPING TEST DATA TEL: (909)920-0707 FAX: (909) 920-0403 Test Dale: 17& 18-Feb-04 Well Name/Number: Wei! PW-1 Circle Well Type: Pumping Observation "^1-= 565 ft) Circle Test Type: Step Drawdown ^^nslanl RaleJ^ Recovery Development Static Water Level Depth: 19.40 ft below RP Reference Poinl Elevation: + 2.00 fl Time Time Time Depth lo Draw-Pumping Sand Totalizer of Step Tolal Waler down Rate Content X 100 Remarks and Olher Data Day [min] [min] [ft] [ft] [gpm] [ppm] [sal] 9:\0AM 19.40 0,00 Pump on 3:28 PM 23.93 4,53 7:26 AM 19.65 0,25 9:12 AM 20.99 L59 10:28 AM 22.40 3.00 11:47 AM 23.23 3.83 1:32 PM 23.83 4.43 3:09 PM 23.95 4,55 5:06 PM 24.44 5,04 6:42 PM 24.61 5,21 8:34 PM 24.76 5.36 10:06 PM 24,85 5.45 12:50 AM 25,08 5,68 3:43 AM 25,22 5,82 9:01 AM 25.00 5.60 Pump off 11:24 AM 22.18 2,78 31-Aug-04 H- 15 GEOSCIENCE Support Services, Inc. Tetra Tcch/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Dale: 17 & 18-Feb-04 Well Name/Number: Well OW-ISH Circle Well Tvoe: ' Pumpina CObservationl> = 555 ft) Circle Test Type: Step Drawdown <^onslant Rale^^ Recovery Development Sialic Water Level Depth: 13.74 ft below RP Reference Point Elevation: + 0.00 ft Time of Day Time Step [min] Time Total [min] Depth to Water [ft] Draw- down [ft] Pumping Rale [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 9:09 AM 13.74 0.00 Pump on 3:30 PM 13.75 0.01 7:26 AM 13.53 -0.21 9:12 AM 13.52 -0.22 10:28 AM 13.51 -0.23 11 ;47 AM 13.51 -0.23 1:32 PM 13.50 -0.24 3:09 PM 13.50 -0.24 5:06 PM 13.52 -0.22 6:42 PM 13.51 -0.23 8:34 PM 13,47 -0.27 10:06 PM 13.45 -0.29 12:50 AM 13.43 -0,31 3:43 AM 13.41 -0,33 9:01 AM 13.38 -0,36 Pump off 11:24 AM 13.30 -0,44 31-Aug-04 H- 16 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: Well 2A/B2/MW1 -S Circle Well Type: Pumping C^bservationl^ 2,200 ft) Circle Test Type: Step Drawdown <^onstanl Ra^e^ Recovery Development Static Water Level Depth: 12.27 ft below RP Reference Point Elevation: -t-2.14 ft . Tirhe . of Day Time Step [min] Time Tolal [min] Depth to Waler [ft] Draw- down [ft] Pumping Rale [gpm] Sand Conlenl [ppm] Totalizer X 100 [gal] Remarks and Other Data 9:52 AM 12.27 0.00 3:58 PM 13,02 0.75 6:50 AM 12,13 -0.14 8:35 AM 12.13 '0.14 Pump on 9:55 AM 12.37 0.10 11:09 AM 12.59 0.32 12:47 PM 12.83 0.56 2:20 PM 13.02 0.75 4:11 PM 13,19 0.92 7:20 PM 13,41 1.14 9:15 PM 13.47 1.20 11:20 PM 13.57 1.30 1:32 AM 13.67 1.40 5:50 AM 13.81 1.54 9:28 AM 13,82 1.55 Pump off 11:00 AM 13,48 1.21 1:44 PM 12,95 0.68 31-Aug-04 H- 17 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Suppoit Services, Inc, Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: Well 2A/B2/MW1-D Circle Well Type: Circle Test Type: Pumping Step Drawdown bservati6rrr&^ 2,200 ft) onstanlRate^]]!^ Recovery Development Static Water Level Depth: 11,96 ft below RP Reference Point Elevation: -i- 2,16 ft Time of Day Time Step [min] Time Tolal [min] Depth lo Waler [ft] Draw- down [ft] Pumping Rale [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 9:52 AM 11,96 0.00 3:58 PM 12,06 0,10 6:50 AM 11,89 -0.07 8:35 AM 11,92 -0.04 Pamp on 9:55 AM 11,99 0.03 12:47 PM 12,03 0.07 2:20 PM 12.00 0.04 4:11 PM 12.05 0.09 7:20 PM 12.06 0.10 9:15 PM 12.07 0.11 11:20 PM 12.11 0.15 1:32 AM 12.07 o.n 5:50 AM 12.07 0.11 9:28 AM 12.03 0.07 Pump off i 1:00 AM 11,94 -0.02 31-Aug-04 H-1; GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development PUMPING TEST DATA TEL (909) 920-0707 FAX: (909) 920-0403 Test Dale: 17 & 18-Feb-04 Well Name/Number: Well 2B/BI/MW] Circle Well Type: Pumping C:5bsen^ir^= 2,000 ft) Circle Test Type: Step Drawdown Constant Rale_J^ Recovery Development Sialic Water Level Depth: 13,94 ft below RP Reference Poinl Elevation: + 1,96 fl Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rale Conlenl X 100 Remarks and Olher Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 8:00 AM 0,00 22,48 0.00 Pump on •9:00 AM 60 22.78 0.30 10:00 AM 120 23.28 0.80 11:00 AM 180 23.70 1.22 12:00 PM 240 24.03 1,55 1:00 PM 300 24.29 1.81 2:00 PM 360 24.51 2.03 3:00 PM 420 24,69 2.21 4:00 PM 480 24,85 2,37 5:00 PM 540 24.99 2.51 6:00 PM 600 25,12 2.64 7:00 PM 660 25,23 2,75 8:00 PM 720 25.32 2,84 9:00 PM 780 25.39 2.91 10:00 PM 840 25.46 2.98 11:00 PM 900 25,51 3,03 12:00 AM 960 25.57 3,09 1:00 AM 1020 25.62 3.14 2:00 AM 1080 25.67 3.19 3:00 AM 1140 25,71 3.23 4:00 AM 1200 25,75 3.27 5:00 AM 1260 25,80 3.32 6:00 AM 1320 25.83 3.35 7:00 AM 1380 25.85 3.37 8:00 AM 1440 25,89 3.41 9:00 AM 1500 25.85 . 3.37 Pump off 10:00 AM 1560 25.37 2.89 11:00 AM 1620 24.88 2.40 12:00 PM 1680 24.45 1,97 1:00 PM 1740 24.11 1.63 31-Aug-04 H- 19 GEOSCIENCE Support Services, Int. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc, Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: 32/Bl/MWl Circle Well Type: Circle Test Type: Pumping • Step Drawdown Qbservalion^= 3,100 ft) onstanl R^te^ Recovery Development Static Waler Level Depth: 14.21 ft below RP Reference Poinl Elevation: + 3 58 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rale Conlenl X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 9:46 AM 14.21 0.00 Pump on 3:52 PM 15.04 0.83 7:00 AM 13.97 -0.24 8:46 AM 13,96 -0,25 10:02 AM 14,20 -0.01 10:19AM 14,49 0.28 1:00 PM 14.83 0.62 2:30 PM 15.09 0.88 4:22 PM 15.35 1.14 7:15 PM 15,60 1.39 9:10 PM 15,77 1,56 JLT6PM 15,94 1,73 1:35 AM 16.05 1,84 5:30 AM 16.23 2.02 9:33 AM 16.28 2.07 Pump off 1:38 PM 15.35 1.14 31-Aug-04 H-20 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H • GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909) 920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17&18-Feb-04 Well Name/Number: Well 3B/B1/MW1 Circle Well Type: Pumping CObservalionj^= 4,100 ft) Circle Test Type: Step Drawdown ^Constant Rate]]!5 Recovery Development Static Waler Level Depth: 21.76 ft below RP Reference Point Elevadon: + 3.42 ft Time of Day Time Step [min] Time Tolal [min] Depth lo Waler [ft] Draw- down [ft] Pumping Rate [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 9:32 AM 21.76 0.00 Pump on 3:41 PM 21,62 -0.14 7:09 AM 21,64 -0.12 8:56 AM 21.66 -O.IO 10:11 AM 21.66 -0,10 11:30 AM 21.66 -0.10 1:03 PM 21.65 -0.11 2:44 PM 21.65 -0.11 4:32 PM 21.64 -0.12 6:58 PM 21.64 -0.12 8:55 PM 21.65 -0,11 11:15 PM 21,65 -0.11 1:16 AM 21,65 -0,11 5:45 AM 21,64 -0.12 9:10 AM 21,63 -0,13 Pump off 10:43 AM 20.78 -0,98 11:20 AM 21.62 -0,14 31-Aug-04 H-21 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc, Ground Water Resources Development PUMPING TEST DATA TEL (909) 920-0707 FAX: (909) 920-0403 Test Date: 17 & 18-Feb-04 Well Name/Number: Well 3B/B2/MW2-S Circle Well Type: Pumping £)bservalionJj>= 4,100 fl) Circle Test Type: Step Drawdown :^OTslant Rate]!^ Recovery Development Static Water Level Depth: 20.70 ft below RP Reference Point Elevation: -i- 1 83 ft Time Time Time Depth to Draw-Pumping Sand Totalizer .of Step Tolal Water down Rate Content X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 7:11 AM 20.49 -0,21 8:58 AM 20.48 -0.22 Pump on 10:12 AM • 20.47 ^0.23 10:31 AM 20,46 -0.24 1:06 PM 20,44 -0.26 2:46 PM 20.42 -0.28 4:34 PM 20.41 -0.29 6:52 PM 20.41 -0,29 8:51 PM 20.44 -0.26 11:06 PM 20,42 -0.28 1:06 AM 20,39 -0.31 5:20 AM 20.40 -0.30 9:14 AM 20.40 -0,30 Pump off 10:44 AM 20.39 -0.31 1:28 PM 20,34 -0,36 31-Aug-04 ,H-22 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: Well 3B/B2/MW2-D Circle Well Type: Pumping jbservalionjy= Constant Rate 4,100 ft) Development Static Water Level Depth: 19,60 ft below RP Reference Poinl Elevation: -i- 1 ,88 ft Time Time Time Depth lo Draw-Pumping Sand Totalizer of Step Tolal Waler down Rale Content X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 7:11 AM 19,61 O.OI 8:59 AM 19,63 0.03 Pump on 10:15 AM 19.63 0.03 10:32 AM 19.63 0.03 1:07 PM 19.59 -0.01 2:48 PM 19.60 0,00 4:35 PM 19.61 0,01 6:54 PM 19.63 0,03 8:52 PM 19.85 0,25 11:10 PM 19.69 0.09 1:11 AM 19.61 0.01 5:22 AM 19.59 -0.01 9:15 AM 19.61 0.01 Pump off 10:45 AM 19.72 0,12 1:29 PM 19.58 -0,02 31-Aug-04 H-23 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Static Water Level = 14,65 - feel below reference point 5 -- I 10 o ca 15 -- 20 Test Date: 17 & 18-Feb-04 Q= 1,850 gpm r = 50 ft 10 D/B2/1VIW1-S (Observation Well) 24-Hour Constant Rate Pumping Test T = 264Q/AS = 174,500 gpd/ft Increase Discharge at D/TW1/PW9 (11:03 p.m.) Recoveiy Pump Off 1.472 min. 100 Time Since Pumping Started, min 1,000 I I I—r 10,000 > •a 0) Q. 31-Aug-04 H-24 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley D/B2/MW1-D (Observation Weil) 24-Hour Constant Rate Pumping Test 10.-- s I 20 -I- 30 -- 40 Static Water Levels 13.88 feet beiow reference point Test Dale: 17 & 18-Feb-04 Q= 1,850 gpm I- r = 50ft • Recovery Pump Off 1472 min 10 100 1,000 Time Since Pumping Started, min 10,000 > •a <D 3 a. X 31-Aug-04 H-25 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley OW-11 (Observation Well) 24-Hour Constant Rate Pumping Test o •o a 2 -- 4 -- 6 -- 10 -- 12 Static Water Level ^19.49 feet below reference poinl Test Date: 17 & 18-Feb-04 Q = 1,850 gpm r = 260 ft Recovery Pump Off 1472 min 10 100 1,000 Time Since Pumping Started, min > -D •o 10,000 3 Q. ><' X 31-Aug-04 H-26 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 0.0 0.2 ^ 0.4 CM c o •D 0.6 0.8 -- 1.0 Static Water Levels 17.91 feet below reference point Test Date: 17 & 18-Feb-04 Q= 1,850 gpm r = 350 ft 10 OW-1 (40 East) (Observation Well) 24-Hour Constant Rate Pumping Test -O « » • • •» •—9—• Pump Off 1472 min 100 1,000 Time Since Pumping Started, min 10,000 > T3 <D a 31-Aug-04 H-27 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley s c •a Static Water Level - 15.84 3 4 -- 5 -- 6 -- 7 -- 9 -I- IC It 12 Test Dale: 17 & 18-Feb-04 0 OW-2 (140 West) (Observation Well) 24-Hour Constant Rate Pumping Test T = 264Q/As = 203,500 gpd/ft As = 2.4 ft Recovery Increase Discharge al D/TW1/PW9 (11:03 p.m ) Pum 10 100 Time Since Pumping Started, min 1,000 > T3 10,000 X* X 31-Aug-04 H-28 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley OW-1 Shallow (Observation Well) 24-Hour Constant Rate Pumping Test 0,0 0.2 ^ 0.4 - - a o S 0.6 -- 0.8 - - I.O Static Water Level = 13.74 feel below reference point Test Dale: 17 & 18-Feb-04 • Q= 1,850 gpm r = 555 ft 10 -9 » » » t e—•—•— Pump Off 1472 min 100 1,000 Time Since Pumping Started, min 10,000 > (D a x' X 31-Aug-04 H-29 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lowcr San Luis Rey River Valley PW-1 (Observation Well) 24-Hour Constant Rate Pumping Test 1 -- 2 -- 3 -- « 4 • • o 5 -- 6 -- 7 -- 9 •- 10 Static Water Level = 19,40 feel below reference poinl Test Date: 17 & 18-Feb-04 Q= 1,850 gpm r = 565 ft 10 Recovery Pump Off 1472 min 100 1,000 Time Since Pumping Started, min 10,000 > •D T3 (D 3 a x' X 31-Aug-04 H-30 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley PW-2 (Observation Well) 24-Hour Constant Rate Pumping Test 2 -- s 6 Sialic Water Levels 19.19 feel below reference point Test Date: 17 & 18-Feb-04 Q= 1,850 gpm r = 565 ft Recovery Pump Off 1472 min iO 100 1,000 Time Since Pumping Started, min 10,000 > TJ (D Q. x" X 31-Aug-04 H-31 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 2A/B2/MW1-S (Observation Well) 24-Hour Constant Rate Pumping Test 1 -- s as 3 Static Water Level = 12.27 feel below reference poinl Test Date: 17 & 18-Feb-04 Q= 1,850 gpm r = 2,200 ft • Recovery Pump Off 1472 min 10 100 1,000 Time Since Pumping Started, min 10,000 > •o Q. x' X 31-Aug-04 H-32 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydroiogic Investigation - Lower San Luis Rey River Valley 0.0 0,1 ^ 0.2 - - o S 0,3 0.4 -- 0.5 Static Water Level = 11,89 feet beiow reference poinl Test Date: 17 & 18-Feb-04 . Q= 1,850 gpm r = 3,500 ft 2A/B2/]V1W1-D (Observation Well) 24-Hour Constant Rate Pumping Test 10 100 Time Since Pumping Started, min Recovery 1,000 10,000 > •o •D (D 3 Q. X* 31-Aug-04 H-33 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 2WBI/MW1 (Observation Well) 24-Hour Constant Rate Pumping Test 1 « 2 -- e o •a i a 3 4 -• • 0 • C » 0 »f Static Water Level = 22.4! feet below reference point Test Dale: 17 lo 18-Feb-04 Q= 1,850 gpm r = 2,000 ft to = 59,5 min = 0,041 day 10 As = 2,6 ft T = 264Q/ As = 188,000 gpd/ft S = 0.3Tto/r^ = 0.0006 100 Time Since Pumping Started, min Recovery Pump Off 1472 min -H- 1,000 10,000 > •D (D 3 Q. x' X 31-Aug-04 H-34 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 3B/B1/MW1 (Observation Well) 24-Hour Constant Rate Pumping Test 0.00 Static Water Level = 21.64 feet • below reference point 0.01 -- c o as 0.02 - - 0.03 Test Dale: 17 & 18-Feb-04 Q= 1,850 gpm r = 4,100 ft Pump Off 1472 min 10 100 Time Since Pumping Started, min 1,000 > -o 10,000 3 Q. x" X 31-Aug-04 H-35 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily Geohydrologic Investigation - Lower San Luis Rey River Valley 3B/B2/IVIW2-S (Observation Well) 24-Hour Constant Rate Pumping Test 0.00 0.02 - • ^ 0.04 • - G O as 0.06 - - 0.08 - - 0.10 Static Waler Level = 20,70 feet below reference point Test Date: 17 & 18-Feb-04 Q= 1,850 gpm r = 4,100 ft . 10 -I 1 1—r -9 • • 9—•——» 100 Time Since Pumping Started, min Pump Off 1472min 1,000 > -a •o 10,000 3 a. x' X 31-Aug-04 H-36 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 3B/B2/MW2-D (Observation Well) 24-Hour Constant Rate Pumping Test 0.0 e 1.0 Sialic Water Level = 19.60 feet below reference point Test Date: 17 & 18-Feb-04 .Q = 1,850 gpm r = 4,000 ft 10 -• • O—• » » »•—9 100 Time Since Pumping Stained, min Pump Off 1,475 min 1,000 > •u 10,000 3 Q. x' X 31-Aug-04 H-37 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 32/Bl/MWl (Observation Well) 24-Hour Constant Rate Pumping Test I -- e o as 2 •• Sialic Water Level - 14.21 feet below reference point Test Date: 17 & 18-Feb-04 Q= 1,850 gpm r = 3,100 ft Recovery Pump Off 1472 min 10 100 1,000 Time Since Pumping Started, min 10,000 > •a •o (D 3 Q. X* X 31-Aug-04 H-38 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley D/TW1/PW9 (Pumping Well) 24-Hour Constant Rate Pumping Test Jacob's Straight Line Applied to Recovery Time Since Pumping Stopped (f), min 31-Aug-04 H-39 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley « 4 -- V a 3 "3 10 -- 12 Test Dale: I8-Feb-04 Q= 1,850 gpm r = 50 ft to = 0.22 min = 0.0002 day D/B2A1W1-S (Observation Well) 24-Hour Constant Rate Pumping Test Jacob's Straight Line Applied to Recovery 0.1 LO T = 264Q/AS = 153,000 gpd/ft S = 0.3Tto/r^ = 0.004 10.0 Time Since Pumping Stopped (f), min As = 3.22 ft 100,0 > CD 1,000,0 a x' X 31-Aug-04 H^40 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley s "a 5 -- 10 -- 15 -- 20 -- 25 -- 30 D/B2/]VIW1-D (Observation Well) 24-Hour Constant Rate Pumping Test Jacob's Straight Line Applied to Recovery T = 264Q/AS = 36,500 gpd/ft S = 0 JTto/r^ = 0.013 Test Date: 18-Feb-04 Q= 1,850 gpm r = 50 ft to = 3.8 min = 0.003 day As = 13.38 ft 10 100 Time Since Pumping Stopped (f), min > •o <D 1,000 3 Q. x' X 31-Aug-04 H-41 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 25 a: •o cd u 30 -- 35 OW-2 (140 West) (Observation Well) 24-Hour Constant Rate Pumping Test Jacob's Straight Line Applied to Recovery - • - T = 264Q/AS = 162,800 gpd/ft S = 0.3Tto/r^ = 0.0004 As = 3,0 ft t': time since pumping stopped Test Dale: 18-Feb-04 Q= 1850 gpm r = 340 ft • to = 0.625 min = 0,0004 day • • t 1 1 1 1 i_ 10 Time Since Pumping Stopped (f), min 100 > •D (D 1,000 a x' X 31-Aug-04 H-42 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley s "CB U 1 - 2 -- 3 -- 4 -- 2B/B1/IVIW1 (Observation Well) 24-Hour Constant Rate Pumping Test Calculated Recovery t': time since pumping stopped Test Dale: 18-Feb-04 Q= 1,850 gpm to = 72 min. = 0.05 day r = 2,000 ft As ^ 3.2 ft -M- T = 264Q/AS = 153,000 gpd/ft S = 0.3Tto/r^ = 0.0006 Trendline 10 100 J,000 Time Since Pumping Stopped (t'), min > -a a> 10,000 g_ x' X 31-Aug-04 H-43 GEOSCIENCE Support Services, Inc. APPENDIX H Pumping Test Data Constant Rate Test Data - City of Oceanside Well No. 3 (PW-3) GEOSCIENCE Support Sen'ices, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Re.sources Development PUMPING TEST DATA TEL (909) 920-0707 FAX: (909) 920-0403 Test Date: 17& 18-Feb-04 Well Name/Number: PW-3 Circle Well Type: slumping. > Observation (r = ft) Circle Test Type: Step Drawdov/n ^OTSlant RalT^i^ Recovery Development Static Water Level Depth: 19.25 ft below RP Reference Poinl Elevation: + 0.00 fl Time Time Time Depth lo Draw-Pumping Sand Totalizer of Step Tolal Waler down Rate Content X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [ppm] [gal] 4:00 PM -0 19.08 0.00 0.00 Baseline, 4:02 PM -2 60.44 41.36 1400 Pump on. 4:04 PM -4 52.44 33.36 995 4:06 PM -6 52.09 33.01 995 • 4:08 PM -8 52.24 33.16 995 4:10 PM -10 52.41 33.33 995 4:15 PM -15 52,70 33.62 995 4:20 PM -20 52,91 33.83 995 4:25 PM -25 53,12 34.04 995 4:30 PM -30 53,28 34,20 995 4:40 PM -40 53.55 34,47 995 4:50 PM -50 53,71 34.63 995 5:00 PM -60 53,84 34.76 995 5:15 PM -75 53,94 34.86 995 5:30 PM -90 54,13 35.05 995 5:55 PM -115 54.24 35,16 995 6:20 PM -140 54.35 35,27 995 6:45 PM -J65 54.43 35,35 995 7:10 PM -190 54,48 35,40 995 7:35 PM -215 54,57 35.49 995 8:00 PM -240 54,64 35,56 995 8:25 PM -265 54.81 35,73 995 8:50 PM -290 55.07 35,99 995 9:15 PM -315 55,11 36,03 995 9:40 PM -340 55.15 36.07 995 10:05 PM -365 55.18 36.10 995 10:30 PM -390 55.24 36.16 995 10:55 PM -415 55.28 '36,20 995 11:20 PM -440 55,26 36,18 995 11:45 PM -465 55,34 36,26 995 12:10AM -490 55,36 36.28 995 12:35 AM -515 55,79 36,71 995 1:00 AM -540 55.77 36,69 995 1:25 AM -565 55,80 36,72 995 31-Aug-04 H-44 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: {909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Well Name/Number: PW-3 Circle Well Type: Circle Test Type: ^mpin;£ Step Drawdown Observation (r= fl) <^nstanl RateJ]^ Recovery Development Static Waler Level Depth: 19.25 ft below RP Reference Poinl Elevation: + 0.00 ft Time Time Time Depth lo Draw-Pumping Sand Totalizer of Step Tolal Water down Rale Content X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [sal] 1:50 AM -590 55.84 36.76 995 2:15 AM -615 55.83 36.75 995 2:40 AM -640 55.88 36.80 995 3:05 AM -665 55.87 36,79 995 3:30 AM -690 55.88 36,80 995 3:55 AM -715 55.89 36,81 995 4:20 AM --740 55.90 36,82 995 4:45 AM -765 55,88 36,80 995 5:10 AM -790 55,90 36,82 995 5:35 AM -815 55,90 36.82 995 6:00 AM -840 55,91 36.83 995 6:25 AM -865 55.94 36.86 995 6:50 AM . -890 55.93 36,85 995 7:15 AM -915 55.95 36,87 995 7:40 AM -940 55.93 36.85 995 8:05 AM -965 55.95 36,87 995 8:30 AM -990 55,94 36.86 995 8:55 AM -1015 55,97 36.89 995 9:20 AM -1040 55,93 36.85 995 9:45 AM -1065 55,99 • 36.91 995 10:10 AM -1090 55.96 36,88 995 iO:35 AM -1115 55.96 36,88 995 11:00 AM -1140 55.94 36,86 995 11:25 AM -1165 55.96 36,88 995 11:50 AM -1190 56.00 36.92 995 12:15 PM -1215 56,00 36.92 995 12:40 PM -1240 56,00 36.92 995 1:05 PM -1265 55.99 36,91 995 1:30 PM -1290 56.03 36,95 995 1:55 PM -1315 56.01 36,93 995 2:20 PM -1340 56.00 36,92 995 2:45 PM -1365 56,02 36,94 995 3:10PM -1390 56,00 36.92 995 3:35 PM -1415 56,02 36.94 995 31-Aug-04 H-45 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Sei-vices, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & 18-Feb-04 Wei! Name/Number: PW-3 Circle Well Type: Circle Test Type: ;Mjmpinj Step Drawdown 0^ervation_(r = ft) t^^^tant RateJ]^ Recovery Development Static Water Level Depth: 19.25 ft below RP Reference Point Elevation: + 0.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content X 100 Remarks and Other Data Day [min] [min] [ft] [ft] [Spm] [ppm] [gal] 4:00 PM -1440 55.99 36.91 995 4:25 PM -1465 56.00 36.92 995 4:50 PM -1490 56.01 36.93 995 5:15 PM -1515 55,98 36.90 995 5:40 PM -1540 56,00 36.92 995 6:05 PM -1565 56,01 36,93 995 6:30 PM -1590 55.97 36,89 995 6:55 PM -1615 56.00 36,92 995 7:20 PM -1640 55.99 36.91 995 7:45 PM -1665 55.98 36.90 995 8:10 PM -1690 55.96 36.88 995 8:35 PM -1715 55.97 36.89 995 9:00 PM -1740 55.93 36.85 995 9:25 PM -1765 55.94 36,86 995 9:50 PM -1790 55.93 36.85 995 10:15 PM -1815 55,93 36.85 995 10:40 PM -1840 55,95 36.87 995 11:05 PM -1865 55.92 36.84 995 11:30 PM -1890 55.95 36.87 995 11:55 PM -1915 55.91 36.83 995 12:20 AM -1940 55.96 36,88 995 12:45 AM -1965 55.97 36.89 995 1:10 AM 1990 55.93 36.85 995 1:35 AM -2015 55.89 36.81 995 2:00 AM -2040 55.94 36,86 995 2:25 AM -2065 55,93 36.85 995 2:50 AM 2090 55,91 36.83 995 3:15 AM -2115 55,92 36.84 995 3:40 AM -2140 55,93 36.85 • 995 4:05 AM -2165 55.93 36.85 995 4:30 AM -2190 55.92 36.84 995 4:55 AM -2215 55.95 36,87 995 5:20 AM -2240 55.89 36,81 995 5:45 AM -2265 55.93 36.85 995 31-Aug-04 H-46 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 17 & I8-Feb-04 Well Name/Number: PW-3 C^mpin^" Circle Well Type: Circle Test Type: Static Water Level Step Drawdown Depth: 19.25 ft below RP Observation (r = ft) <Constant Ra^^]]I> Recovery Development Reference Point Elevation: + 0.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rale Content X 100 Remark.s and Other Data Day [min] [min] [ft] [ft] [gpni] [ppm] [gal] 6:10 AM -2290 55.90 36,82 995 6:35 AM -2315 55.91 36,83 995 7:00 AM -2340 55.90 36,82 995 7:25 AM -2365 55.92 36.84 995 7:50 AM -2390 55,88 36.80 995 Pump off. 8:15 AM -2415 22,58 3.50 Recovery 8:40 AM -2440 21,55 2.47 Recovery 9:05 AM -2465 21.12 2.04 Recovery 9:30 AM -2490 20.85 1.77 Recovery 9:55 AM 2515 20,66 1.58 Recovery 10:20 AM -2540 20,52 1.44 Recovery 10:45 AM -2565 20,41 1.33 Recovery 11:10 AM -2590 20.31 • 1.23 Recovery 11:35 AM -2615 20,23 1.15 Recovery 12:00 PM -2640 20.16 1,08 Recovery 12:25 PM -2665 20.10 1.02 Recovery 12:50 PM -2690 20.05 0.97 Recovery 1:15 PM -2715 19.99 0.91 Recovery 1:40 PM -2740 19,96 0.88 Recovery 31-Aug-04 H-47 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX; (909) 920-0403 PUMPING TEST DATA Test Date:20, 21 & 22-Ocl-03 Well Name/Number: Weil OW-11 Circle Well Type: Circle Test Type: Pumping Step Drawdown )bservatiorr$r = 195 ft) Constant Rale Recovery Development Static Waler Level Depth: 22.55 ft below RP Reference Point Elevation: 0 ft Date Military Time Time Tolal [min] Depth to Water [ft] Draw- down [ft] Pumping Rale [gpm] Sand Content [ppm] Totalizer X 100 • [gal] Remarks and Olher Data 10/20/03 908 0 24.10 0,00 ---Baseline moniloring 10/20/03 1450 0 22.55 0.00 ---Baseline monitoring 10/20/03 1623 23 22.23 0.32 995 --PW-3 pump on [16:00] 10/20/03 1708 68 22.43 0.12 995 -- 10/20/03 1810 130 22,73 -0.18 995 -- 10/21/03 807 967 24,42 -1.87 995 -- 10/21/03 1051 1131 24.57 -2,02 995 -- 10/21/03 1230 1230 24,52 -1,97 995 -- 10/21/03 1620 1460 24,48 -1,93 995 - 10/22/03 726 2366 24,42 -1.87 995 -- 10/22/03 807 2407 24,51 -1.96 ---PW-3 pump off [08:00] 10/22/03 831 2431 24,37 -1.82 ---Recovery 10/22/03 946 2506 23.73 -1,18 ---Recovery 10/22/03 1020 2540 23.45 -0,90 --Recovery (0/22/03 1101 2581 23.10 -0,55 ---Recovery 10/22/03 1205 2645 22.59 -0,04 --Recovery 10/22/03 1251 2691 22,26 0.29 ---Recovery 10/22/03 1330 2730 22,04 0,51 - • --Recovery 31-Aug-04 H-48 GEOSCIENCE Support Services, Inc. Tetra Tech/San Oiego County Water Authority Geohydrologic Investigation - Lower San Luis Rey Rivcr Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Devekipmeni TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date:20, 21 & 22-Oct-03 Well Name/Number: Well OW-1 (40 East) Circle Well Type: Circle Test Type: Static Waler Level Pumping Step Drawdown Depth: 17.68 ft below RP )bservation^ = 130 Constant Rate Recovery ft) Development Reference Point Elevation: 0 ft Dale Mililaiy Time Time Tolal [min] Depth to Water [ft] Draw- down [ft] Pumping Rate [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 10/21/03 856 0 17.90 0.00 ---Baseline monitoring 10/21/03 1418 0 17.68 0.00 ---Baseline monitoring 10/2J/03 1614 12 17.65 0.25 995 --PW-3 pump on [16:00] 10/21/03 1703 63 17.68 0,22 995 -- 10/21/03 1815 135 17.67 0,23 995 -- 10/22/03 738 938 17.69 0.21 995 -- 10/22/03 1049 1129 17.72 0.18 995 -- 10/22/03 1235 1235 17.69 0.21 995 -- 10/22/03 1616 1456 17.67 0.23 995 -- 10/23/03 724 2364 17.70 0.20 995 -- 10/23/03 805 2405 17,70 0.20 ---PW-3 pump off 10/23/03 828 2428 17,72 0.18 ---Recovery 10/23/03 953 2513 17,70 0.20 ---Recovery 10/23/03 1207 2647 17.66 0.24 ---Recovery 10/23/03 1248 2688 17.68 0.22 ---Recovery 10/23/03 1328 2728 17.58 0.32 ---Recovery 31-Aug-04 H-49 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valtey Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date:20,21 &22-Oct-03 Well Name/Number: Well OW-1 Shallow Circle Well Type: Circle Test Type: Pumping Step Drawdown tjervaljonjr= 480 ft) _jstanl Ra^]]!^ Recovery Development Reference Point Elevation: 0 fl Dale Military Time Time Total [min] Depth lo Waler [ft] Draw- down [ft] Pumping Rate [gpm] Sand Conlenl [ppm] Totalizer X 100 [gal] Remarks and Other Data 10/21/03 912 0 15,10 0.00 ---Baseline moniloring 10/21/03 1425 0 14.65 0,00 ---Baseline moniloring 10/21/03 1648 48 14.92 -0,27 995 --PW-3 pump on [16:00] 10/21/03 1827 147 15.92 -1,27 995 -- 10/22/03 748 948 14.99 -0.34 995 -- 10/22/03 1056 1136 15.02 -0.37 995 -- 10/22/03 1236 1236 15,01 -0.36 995 -- 10/22/03 1623 1463 15.00 -0.35 995 -- 10/23/03 730 2370 15.00 -0.35 995 - 10/23/03 811 2411 15.00 -0,35 ---PW-3 pump off 108:00] 10/23/03 836 , 2436 15.0! -0.36 --Recovery 10/23/03 951 2511 14.97 -0.32 ---Recovery 10/23/03 1208 2648 14.87 -0,22 ---Recovery 10/23/03 1335 2735 14.82 -0,17 ---Recovery 31-Aug-04 H-50 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Dale:20, 21 & 22-Ocl-03 Well Name/Number: Weli 2A/B2/MW1-S Circle Well Type: Circle Test Type: Pumping Step Drawdown 2,700 ft) Recovery Reference Point Elevation: 2.14 ft Development Dale Military Time Time Tolal [min] Depth to Water [ft] Draw- down [ft] Pumping Rale [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 10/20/03 1219 0 12.97 0.00 --Baseline monitoring 10/20/03 1756 116 12.92 0.05 995 --PW-3 pump on [16:00] 10/21/03 1008 1088 13.46 -0.49 995 -- 10/21/03 1500 1380 13.43 -0.46 995 -- 10/22/03 .715 2355 13,49 -0.52 • 995 -- 10/22/03 907 2467 13.45 -0.48 ---PW-3 pump off [08:00] 10/22/03 1130 2610 13.24 -0,27 ---Recovery 10/22/03 1250 2690 13.15 -0,2 ---Recovery 31-Aug-04 H-51 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation • Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date:20, 21 & 22-Oct-03 Well Name/Number: Well 2A/B2/MW1-D Circle Weil Type: Circle Test Type: Pumping Step Drawdown = 2,700 ft) ronslant RaleJ!) Recovery Reference Point Elevation: 2,11 ft Development Dale Military Time Time Total [min] Depth to Waler [ft] Draw- down [ft] Pumping Rale [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 10/20/03 1221 0 11.96 0.00 ---Baseline monitoring 10/20/03 1758 118 11.88 0.08 995 --PW-3 pump on [16:00] 10/21/03 1009 1089 12.01 -0.05 995 -- 10/21/03 1500 1380 11.69 0.27 995 -- 10/22/03 716 2356 11.96 0.00 995 -- 10/22/03 908 2468 12.00 -0.04 ---PW-3 pump off [08:00] 10/22/03 1131 2611 11.95 0.01 ---Recovery 10/22/03 1251 2691 11.96 0.0 ---Recovery 31.Aug-04 H-52 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date:20, 21 & 22-Oct-03 Well Name/Number: Well 3B/B2/MW2-S Circle Well Type: Circle Test Type: Pumping Step Drawdown )hse^^on^ 3,800 fl) Constant RaleJ^ Recovery Development Static Water Level Depth: 21.17ft below RP Reference Point Elevation: 1.83 ft Dale Military Time Time Total [min] Depth lo Waler [ft] Draw- down [ft] Pumping Rate [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 10/20/03 1104 0 21.17 0,00 ---Baseline monitoring 10/20/03 1745 105 21.12 0,05 995 --PW-3 pump on [16:00] 10/21/03 845 1005 21.10 0,07 " 995 -- 10/21/03 1545 1425 21.02 0.15 995 -- 10/22/03 703 2343 20.99 0.18 995 -- 10/22/03 856 2456 21.00 0.17 ---PW-3 pump off [08:00} 10/22/03 1159 2639 20.98 . 0,19 ---Recovery 10/22/03 1300 2700 20.96 0.2 ---Recovery 31-Aug-04 H-53 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Waler Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date:20, 21 & 22-Ocl-03 Well Name/Number: Well 3B/B2/MW2-D Circle Well Type: Circle Test Type: Pumping Step Drawdown )bse^g^n>= 3,800 ft) Constant Ralel!^ Recovery Development Static Water Level Depth; 19.98 ft below RP Reference Point Elevation: 1.88 ft Dale Military Time Time Total [min] Depth lo Waler [ft] Draw- down [ft] Pumping Rale [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 10/20/03 1106 0 19.98 0.00 ---Baseline moniloring 10/20/03 1748 108 19.98 0.00 995 --PW-3 pump on [16:00] 10/21/03 846 1006 20,11 -0.13 995 -- 10/21/03 1548 1428 20,01 -0,03 995 -- 10/22/03 704 2344 20.04 -0,06 995 -- 10/22/03 858 2458 20.06 -0.08 ---PW-3 pump off [08:00] 10/22/03 1200 2640 20.05 -0.07 --Recovery 10/22/03 1301 2701 20.02 0.0 ---Recovery 3I-Aug-04 H-54 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. Ground Waler Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Dale:20, 21 & 22-Oct-03 Well Name/Number: Well 1 IC/Bl/MWl-S Circle Well Type: Pumping C^^^^^n^= 5,600 ft) Circle Test Type: Step Drawdown C^onslantRaje]])) Recovery alic Water Level Depth: 40.01 ft below RP Reference Point Elevation: 1.68 ft Development Dale Military Time Time Total [min] Depth to Waler [ft] Draw- down [ft] Pumping Rale [gpm] Sand Content [ppm] Totalizer X 100 [gal] Remarks and Other Data 10/20/03 1135 0 40.01 0.00 --PW-3 pump on [16:00] 10/21/03 901 1021 40.06 -0.05 995 -- 10/21/03 1557 1437 39.99 0.02 995 -- 10/22/03 652 2332 40.03 -0.02 995 -- 10/22/03 927 2487 40.03 -0.02 ---PW-3 pump off [08:00] 10/22/03 1148 2628 40,03 -0.02 ---Recovery 10/22/03 1320 2720 40.02 -O.OI ---Recovery 31-Aug-04 H-55 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix H GEOSCIENCE Support Services, Inc. TEL:' (909) 920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date:20, 21 & 22-Ocl-03 Wei) Name/Number; Well 1 IC/BI/MWl-D Circle Well Type: Circle Test Type: Pumping Step Drawdown )bservatiotuy -- 5,600 ft) Recovery Development Static Water Level Depth: 36.55 ft below RP Reference Point Elevation: 1.61 ft Dale Military Time Time Total [min] Depth to Waler [ft] Draw- down [ft] Pumping Rate fgpm] ' Sand Content [ppm] Totalizer X 100 [gaJ] Remarks and Other Data 10/20/03 1133 0 36.55 0.00 -. --PW-3 pump on [16:00] 10/21/03 903 1023 35.39 1.16 995 -- 10/21/03-1600 1440 35.33 1.22 995 -• - 10/22/03 654 2334 35.37 1.18 995 -- 10/22/03 929 2489 35.38 1.17 ---PW-3 pump off [08:00] 10/22/03 1150 2630 35.39 1.16 ---Recovery 10/22/03 1321 2721 35.36 1.19 ---Recovery 31-Aug-04 H-56 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley OW-1 (40 East) (Observation Well) 40-Hour Constant Rate Pumping Test 0.00 0.02 - - o •o a 0.04 - - 0.06 Static Water Level = 17.68 feet below reference point Test Date: 20 lo 23-Oct-03 . Q = 995 gpm r= 130 ft .Pump Off 2400 min 10 100 Time Since Pumping Started, min 1,000 > •a -D 10,000 § Q. x' X 31-Aug-04 H-57 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley OW-1 (Shallow) (Observation Well) 40-Hour Constant Rate Pumping Test -0.2 0.0 -- 0.2 -- 0.4 + o es Q 0.6-i- 0.8 -- 1.0 -- 1.2 Static Waler Level = 14.95 feet below reference point Test Date: 20 to 23-Oct-03 Q = 995 gpm I- r= 480 ft 10 100 Time Since Pumping Started, min Recovery Pump Off 2400 min 1,000 > TJ 10,000 § Q. x' X 31-Aug-04 H-58 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Wafer Authority Geohydrologic Investigation - Lower San Luis Rey River Valley s o . •a 4 S 6 7 Static Waler Level 19.78 feet below reference point Test Dale: 20 to 23-Ocl-03 Q = 995 gpm r = 217ft to = 0.45 min = 0.0003 day 0.1 1.0 PW-2 (Observation Well) 40-Hour Constant Rate Pumping Test T = 264Q/AS = 175,000 gpd/ft S = 0.3Tto/r^ = 0.0003 Ar'*' = 0.004/days 10.0 100,0 Time Since Pumping Started, min Pump Off 2400 min 1,000.0 10,000.0 > •o <D Q. x' X 31-Aug-04 H-59 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 10 -- c I 20 + 30 • • 40 Static Water Level = 19.25 feet below reference poinl Test Date: 20 to 22-Oct-03 Q = 995 gpm As = 1.6 ft 10 Oceanside Desalter Well PW-3 (Pumping Well) 40-Hour Constant Rate Pumping Test T = 264Q/AS = 164,000 gpd/ft . • • • I 100 Time Since Pumping Started, min ^Recovery , Pump Off 1,000 10,000 > •a •a <D 3 31-Aug-04 H-60 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 1 -- I 2 + CS 3 -- \ Static Waler Level = 24.98 feel below reference point Test Date: 20 to 23-Oct-03 Q = 995 gpm r = 2.150 ft 10 2B/1V1W1 (Observation Well) 40-Hour Constant Rate Pumping Test 100 Time Since Pumping Started, min Desaller Production Wells Pumping 1,000 I ~i—1—r 10,000 > •o <D a. x" X 31-Aug-04 H-61 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 2A/B2/IVIW1-S (Observation Well) 40-Hour Constant Rate Pumping Test 0.0 0.1 -- 0.2 -- e o as Q 0.4 -I- 0.5 -- 0.6 -- 0.7 10 100 1,000 Time Since Pumping Started, min \ Static Water Level = 12.97 feet below reference point • r -- Recovery Test Date: 20 to 23-Oct-03 Q = 995 gpm - • r = 2,700 ft 1 1 1 1—1—I—1—1— Pump Off 2,400 min 1—' 1 1 f 1—1—I—1— > -o 10,000 § Q. x' X 31-Aug-04 H-62 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 2A/B2/MW1-D (Observation Well) 40-Hour Constant Rate Pumping Test 0.00 0.02 - - o es 0.04 - - 0.06 Static Water Level - 11,96 feet below reference point Test Date: 20 lo 23-Oct-03 Q = 995 gpm r= 2,700 ft 10 100 Time Since Pumping Started, min Pump Off 2,400 min 1,000 > •o 10,000 3 Q. x' X 31-Aug-04 H-63 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 3B/B2/MW2-S (Observation Well) 40-Hour Constant Rate Pumping Test 0.00 0.02 - - o •a ffi 0.04 - - 0.06 Static Water Level ^ 21.17 feet below reference point Test Date: 20 to 23-Oct-03 . Q = 995 gpm r^ 3,800 ft 10 Pump Off 2,400 min 100 Time Since Pumping Started, min 1,000 > •o •a 10,000 3 Q. x' X 31-Aug-04 H-64 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 3B/B2/1VIW2-D (Observation Well) 40-Hour Constant Rate Pumping Test 0.00 0.04 - - • Static Waler Level = 19.98 feet below reference point c I 0.08 + es 0.12 -- 0.16 Test Date: 20 lo 23-Oct-03 Q = 995 gpm r= 3,800 ft 10 100 1,000 Time Since Pumping Started, min Recovery > •a 10,000 § a x' X 31-Aug-04 H-65 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley llC/Bl/IMWl-S (Observation Well) 40-Hour Constant Rate Pumping Test 0.00 . Static Water Level = 40.01 feet below reference poinl ^ 0.04 - - a o as 0.08 - - Test Dale: 20 to 23-Ocl-03 Q = 995 gpm r= 5,600 ft Recovery Pump Off 2,400 min 100 1,000 Time Since Pumping Started, min > •D 10,000 3 a. x' X 31-Aug-04 H-66 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley IIC/BI/IMWI-D (Observation Well) 40-Hour Constant Rate Pumping Test 0.00 ^ 0.04 - - e o •B fi as 0.08 - - Static Waler Level 3: 36.55 feet below reference point Test Dale: 20 to 23-Oct-03 Q = 995 gpm r= 5,600 ft 100 Pump Off 2,400 min 1,000 Time Since Pumping Started, min > 10,000 § X X 31-Aug-04 H-67 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 1 -- 2 -- 3 -- > o u a; Pi 4 -- 6 -- 7 -- PW-2 (Observation Well) 40-Hour Constant Rate Pumping Test Calculated Recovery As= 1.7 ft i': time since pumping stopped i{i = 2.0 minutes = 0.0014 days Test Date: 22-Ocl-03 Q = 995 gpm h r = 217ft T = 264Q/AS = 154,500 gpd/ft S = 0.3 T t„/r = 0.0014 > T3 (D 1,000 g_ x' X 10 100 Time Since Pumping Stopped (f), min 31-Aug-04 H-68 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Wafer Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 6 > o u ai -e 20 V a 3 u "a U 25 40 PW-3 (Pumping Well) 40-Hour Constant Rate Pumping Test Jacob's Straight Line Applied to Recovery • t': lime since pumping stopped --Test Date: 22-Oct-03 \ Q = 995 gpm \ T = 264Q/AS = 131,00 gpd/ft i -As = 2.0 ft ^ r . 1 1 1 1 1—1—1—t— 1 1 1 1 l_I—t—1_ ' ' '— * 1 10 Time Since Pumping Stopped (f), min 100 > •a <D 1,000 g_ x' X 31-Aug-04 H-69 GEOSCIENCE Support Services, Inc. APPENDIX I Chronology of Construction - Desalter Test Well D/TW1/PW9 GEOSCIENCE Support Sen'ices. Inc. Tetra Tech/San Diego County Waler Authority Appendix I Geohydrologic Investigation - Lower San Luis Rey Rivcr Valley Chronology of Construction D/TW1/PW9 lO-Dec-03 Conductor casing is installed into the 42-inch diameter borehole to a depth of 51 feet below ground surface. The conductor casing is 30 inches in diameter with a wall thickness of 5/16 inches. A tremie pipe is installed at 45 feet below ground surface (ft bgs). A total of 17 yards of grout was pumped, completing the sanitary seal witnessed by Larry Newcomb of the County of San Diego DHS. 7- Jan-04 WDC Exploration & Wells begins drilling 17 '/2-inch diameter pilot borehole using reverse circulating drilling method. Pilot borehole drilled to 107 ft bgs. 8- Jan-04 Deviation survey V2 degree from center at 100 feet below ground surface. Pilot borehole drilled to 280 ft bgs. Deviation survey Vi degree from center at 280 ft bgs. 9- Jan-04 Pilot borehole drilled to total depth of 302 ft bgs. Pacific Surveys conducts geophysical logs in pilot borehole. Bentonite bottom seal installed from 262 to 302 ft bgs (bentonite mixed 1:1 by volume with 5/16" gravel.) Zone test tool (0.050 slot size) installed for Zone 1 (245 to 265 ft bgs). Gravel pack installed for Zone 1 from 235 to 262 ft bgs (RMC 8 mesh). Bentonite top seal installed for zone test (upper seal tagged at 216 ft bgs). 10- Jan-04 Airlift development of Zone 1. Installing 4-inch submersible pump to 199 ft bgs inside 8-inch diameter zone test tool. Start Zone 1 pumping at approximately 10 gallons per minute (gpm). 11- Jan-04 Seal on Zone 1 not intact; water level in conductor dropping. 31-Aug-04 GEOSCIENCE Support Services, Inc. I-l Tetra Tech/San Diego County Water Authorily Appendix I Geohydroiogic Investigation - Lower San Luis Rey River Valley 12-Jan-04 Submersible pump removed from inside zone test tool. Zone test tool removed from borehole. 13- Jan-04 Zone 1 testing completed; water samples taken and delivered to Del Mar Labs. Zone 2 (190-210 ft bgs) testing preparation. 14- Jan-04 Zone 2 (190-210 ft bgs) airlifting commences. 15- Jan-04 Zone 2 (190-210 ft bgs) airlifting continued and completed. Water quality samples collected, delivered to Del Mar Labs. 16- Jan-04 Zone 3.(120-140 ft bgs) airlifting commences. 19-Jan-04 Zone 3 (120-140 ft bgs) airUfting continued, completed. Water quality samples collected and delivered to Del Mar Labs. 23- Jan-04 WDC Exploration & Wells pulling zone test tools. H2S monitored, not detected. Reaming pass conducted to clean out borehole. 24- Jan-04 Reaming completed. Pacific Surveys conducts caliper log. Casing installation begins. Tremie pipe to 240 ft bgs installed. 25- Jan-04 WDC set well casing to 5 ft above ground. Backfilling and installing of filter pack (1/4 X 16) commenced. A total of 13 supersacks of filter pack (1/4 x 16) and 3 supersacks of gravel in place for approximately 480 ft'^. A total of 13 gallons of chlorine added concurrently to the filter pack installation. 26-Jan-04 Annular seal poured and curing. Filter pack tagged to 50 ft bgs. A total of 7 yd poured. 3!-Aug-04 GEOSCIENCE Support Services, Inc. 1-2 Tetra Tech/San Diego County Water Authority Appendix I Geohydrologic Investigation - Lower San Luis Rey River Valley ^ 27- Jan-04 Initial airlift development begins at 3:10 PM. Airlifting at 120 ft to 140 ft bgs at approximately 20 gpm for 2 hours. Tagged filter pack within gravel feed tube at 51.6 ft below reference point (23 inches above ground surface). 28- Jan-04 Initial airlift development continues and is completed at 12:50 PM. Commence airlift development and swabbing of the screened intervals (100 to 160 ft bgs). 29- Jan-04 Continued airlift development and swabbing of the screened intervals (160 to 220 ft bgs). Conditioned screened intervals with PFD. 30- Jan-04 Complete airlift development and swabbing of the screened intei;vals. lO-Feb-04 Began pump development at approximately 60 gpm. A maximum pumping rate of 1,500 gpm was achieved with an average specific capacity of 51.72 gpm/ft. - ll-Feb-04 Continued pump development. A maximum pumping rate of 2,000 gpm was achieved with an average specific capacity of 52.68 gpm/ft. 12- Feb-04 Continued pump development A maximum pumping rate of 2,000 gpm was achieved with an average specific capacity of 50.55 gpm/ft. 13- Feb-04 Completed pump development. A maximum pumping rate of 2,100 gpm was achieved with an average specific capacity of 52.84 gpm/ft. Approximately 31.1 hours of pump development was achieved. 16- Feb-04 Step Drawdown test begins at 10:10 AM. Steps conducted at 1000 gpm, 1500 gpm, and 2000 gpm, respectively. 17- Feb-04 24-Hour Constant Rate (1800 gpm) test begins at 8:00 AM. 18- Feb-04 24-Hour Constant Rate (1800 gpm) test concludes at 8:15 AM. Water quality samples taken. Recovery monitored until 1:30 PM. 27-Feb-04 Video Survey and deviation studies conducted. Video survey completed at 9:50 AM, deviation complete by 10:30 AM. 31 -Aug-04 GEOSCIENCE Support Services, Inc, 1-3 APPENDIX J Mechanical Grading Analysis - Desalter Test Well D/TW1/PW9 GEOSCIENCE Support Sen'ices. Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Mechanical Grading Analysis DyTWl/PW9 (100-107 ft) 100 90 70 ^ 60 c as Cu Pu 50 40 30 20 10 1' X 1 f 1 t t 1 I J m J W~ f 1 ( / 1 1 / t 1 1 aeai i<iuer FacK f f 1 1 1 t * It 1 a M t M 0.01 2> 04 1 • 1 J9-U Sieve Opening, mm "O T3 (D 3 a x' c 31-Aug-04 J- 1 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigafion - Lower San Luis Rey River Valley Mechanical Grading Analysis D/TW1/PW9 (120-130 ft) 100 90 80 70 ^ 60 c as a. 50 S 40 30 20 10 0.01 I' '/ 1 £ c .0 o A f 11 1 / m 1 1^ / 1 - g 1^ / § IHPSI Filfpr Park i / 11 r 1 I / n / / / r ! ! —< f ! ! ! ! ! 0.1 10 100 Sieve Opening, mm > XJ •o 3 Q. 31-Aug-04 S-2 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Mechanical Grading Analysis D/TW1/PW9 (140-150 ft) 100 90 80 70 ^ 60 c u S 40 30 20 10 "1 J r / r 0 1— /l' / / f / 1 1 t T 1 deal Filter Pack i 1 f t 1 j 1 1 * f 1 1 • f M t M 7 n —< 0 —1 ? —1 * \ • Sieve Opening, mm > T3 •D O 3 Q. 31-Aug-04 J-3 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Mechanical Grading Analysis D/TW1/PW9 (160-170 ft) 100 90 80 70 ^ 60 as fi. 50 S 40 30 20 10 ©T" A r 0 § 1 1 M. 1 • 1 # r 1 • 1 • • fl If 1 pfll Fiifpr Park J f J f 1 i f f f y f 1 1 ' « /I 1 i / 1 f / M t —< 0-! 1 \ r Sieve Opening, mm > •o 3 Q. x' 31-Aug-04 J-4 GEOSCIENCE Support Services, Iiic. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lovi'er San Luis Rey River Valley Mechanical Grading Analysis D/TW1/PW9 (190-200 ft) 100 90 80 70 ^ 60 BE P 40 30 20 10 7,^ # /' r 1 * r • 1 t 1 1 'f / 1 f I deal Filter Pack f f f f / / • (. f y —< 1 <• : ! ! II 1 Sieve Opening, mm > •D <D 3 Q. S' C 31-Aug-04 J-5 GEOSCIENCE Support Services, Inc. APPENDIX K Well Completion Details - Desalter Test Well D/TW1/PW9 GEOSCIENCE Support Services. Inc. 3 In. Sch. 40 grovd feed pipe (to 57 57 100- . " w 150- 200- 220 250- :: - -b l ' P " t q -. . 0-Qh;O.Q,O.ttoQC 9.* o.^ p.*. 0. Ot|O.QQtt-iQa a QfLQ a-Qft Q fa Q-o Ja D 6. o.a pb. o • o • (, 0.(10Ci..0.a-Db;C WELL CROSS SECTION -Air vent pips -2 In. Sch. 40 SS Tj^ie 304 sounding tube (to 97 ft) -42 in. borehole (0-50 ft) -30 In. 00 n S/16 in. wall conductor cosing (to 50 ft) -10.5 Sk aonij—cement seal (to 50 ft) -2G in. borehole (50-250 ft) -16 In. ID K 5/lB In. wall SS Type 304L blank casing (0-100 ft) -Sted centraliiers -Custom blend ^/* in. x 16 fnter pock (50-302 ft) -)B in. JD X 5/16 In. wall SS Tjpe 304L Ful-Flo louvarad screen with 0.094 In. ^enings (100-220 ft) -16 in. ID X 5/16 in. wall SS Type 304L bionk cosing w/end plate (220-240 ft) -17 1/2 In. pilot borehole (to 302 ft) RSN (ohm-m) 0 50 TD-302- ol.\qai(tr7.aat Toline WanrQiialil) • DmLicrTr^r Wrll PjTWIfi'W^ <;m"jnJy>>irr Analijicai I5aln - Dh,olv*d .Mtr»li \ 1 l,r'cl in IH..I Purer" "£ Wnt.T "iniivV R-lr IffPfnl CilciBin I Iriq iribt-l \ 1 l,r'cl in IH..I Purer" "£ Wnt.T "iniivV R-lr IffPfnl CilciBin I Iriq 1 iJ ' 1 (1.(11S 1,1 iji •) 1 1 1 1, ,,O.M., 1 1 4-11 •>M Cn>iintl^-a1rr AiijiL>1ic jl Dufa - Inorganics /..».- Siiild- tinslLI Nirr.rr pH 1^1 •\ r..liir |.:M<I Ud..r II.O.N.I 1 I'll! D.n ilii NA ' .11 I<1 ••I 0 6i 31 !J <1 iJ 60 =o:; JIO' :}•> <! ll Jin- c;ravel Park Castimi D)CBd J/4 i Ifc r.s. SlJ. Sine OypninE*. .Microns % Pacing 3.S 132 imi IfJ iir-K K; » 4 » IS? J 71. ih) K iii>i] 1?4 t; II M. 11,11 .< 1 1!. nm7 l.i'J 1.4 RESISTIVITY LOG AND AQUIFER ZQNF TFST INTFRVAI (D ^— OCL Ul 2: o I—^ w CO ^ o \ ps s ^ w APPENDIX L Development Notes - Desalter Test Well D/TW1/PW9 GEOSCIENCE Support Sen'ices, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lowcr San Luis Rey River Valley Appendix L GEOSCIENCE Support Service;, Inc. TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: IO-Feb-04 Well Name/Number: .Desalter Test Well D/TW 1 /PW9 Circle Well Type: CCumpini^ Circle Test Type: Step Drawdown Static Water Level Depth: 21.60 ft below RP Observation (r = ft) Constant Rate Recovery Reference Point Elevation: + 2, C^Developmen^ OOft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content X 100 Remarks and Other Data Day [mini [min] [ft] [ft] [gpm] [ppm] [gal] 12:45 PM 60 7.00 29422 mica, clear 1:00 PM 24.3 3.7, 60 4.00 29426 .slight H2S odor 1:15 PM 21.3 0.3 80 tr 29435 1:30 PM 22.4 0.8 100 tr 29451 1:45 PM 23.9 2.3 200 tr 29470 2:00 PM 210 tr 29509 2:08 PM 25.5 3.9 300 tr 29532 2:18PM 25.6 4.0 300 tr 29565 2:30 PM 400 tr 29608 2:40 PM 27.2 5.6 400 tr 29649 3:00 PM' 29.2 7.6 500 tr 29733 3:30 PM 32.3 10.7 650 tr 29884 .surging x 1 3:45 PM 700 tr 29983 3:53 PM 33.4 11.8 tr 30063 3:57 PM 850 tr 4:00 PM 38,0 16.4 850 Ir 30110 4:06 PM 37.3 15.7 S50 tr 30162 4:20 PM 39.4 17.8 1,050 tr 30299 4:22 PM 40.8 19.2 1,000 surging \ 3 4:25 PM 1,500 30366 4:33 PM 49.0 27.4 1.500 30475 4:47 PM 49.0 27.4 1,500 30683 4:54 PM tr 4:56 PM 49.3 27.4 1,500 tr 30818 5;05 PM 1,500 tr 30952 6:06 PM 50.6 . 29.0 1,500 tr shutciown total 153,000 gal/3.25 hrs 31-Aug-04 L-l GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix L GEOSCIENCE Suppoit Services, Inc. Ground Water Resources Development PUMPING TEST DATA ICL: (,yuyj yzu-u/u/ FAX: (909) 920-0403 Test Date: ll-Feb-04 Wel] Name/Number: Desalter Test Well D/TWI/PW9 Circle Well Type: C ^.Pumping, Observation (r = ft) Circle Test Type: Step Drawdown Constant Rate Recovery <Clpevel opment_]^ Static Water Level Depth: 21.90 ft below RP Reference Point Elevation: + 2.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content Retnarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] fgal] 7:50 AM 500 30985 8:04 AM 34.0 21.1 750 8:07 AM 750 tr 31101 8:12 AM 34.0 12.1 Surging x 2 8:15 AM 33.6 11.7 750 tr 31159 (807 gpm) 8:30 AM 34.1 12.2 800 31280 Shutdown, pump off 8:57 AM 20.9 -1.0 Pump off 9:35 AM 20.5 -1.4 31283 Pump off .10:27 AM 20.4 -1.5 800 Pump on, .surging x 2 10:34 AM 34.5 12.6 800 31322 .slightly cloudy from air 10:40 AM tr 31378 shut down, leak at end 10:49 AM 22.3 0.4 off 11:03 AM 21.9 0.0 750 Pump on, surging x 2 11:05 AM 31384 pump off 11:06 AM 750 pump on 11:08 AM 950 tr 11:09 AM 35.1 13.2 31407 11:24 AM 36.5 14.6 tr 31547 (933 gpm) 11:25 AM 900 surging x 1 11:28 AM 38.0 16,1 1,000 31580 (1044 gpm) 11:44 AM 38.9 17.0 1,025 31747 surging x 1 11:46 AM 1,025 31760 11:50 AM 40.8 18.9 1,100 11:58 AM 41.4 19.5 1,150 tr 31898 (1150 gpm) 11:59 AM surging x 1 12:01 PM 1,200 31925 12:08 PM 42.7 20.8 1,250 tr 32011 (1229 gpm) 12:10 PM 1,300 surging X 1 12:12PM 44.3 22.4 1,300 32052 {1340 gpm) 12:32 PM 46.8 24.9 1,300 tr 32320 surging X 1 12:34 PM 1,400 32337 12:51 PM 49.0 28.1 1,450 tr 32593 (1506 gpm) 12:52 PM surging x 5 12:55 PM 51.0 30.1 1.600 32623 31-Aug-04 L-2 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix L GEOSCIENCE Support SeiA-ices, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: ll-Feb-04 Well Name/Number: Desalter Test Well DmVl/PW9 CPumpin^ Circle Well Type: Circle Test Type: Step Drawdown Observation (r = Constant Rate ft) Recovery C||^eveloprTient_]l!!> Static Water Level Depth: 21.90 ft below RP Reference Point Elevation: -f 2.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Waler down Rate Content Remarks and Other Data Day [min] [min] [ft] [ft] f^Pf"] [ppm] 1:08 PM 51.6 30.7 1,600 tr 32835 (1631 gpm) 1:09 PM surging x 5 1:12 PM 52.0 31.1 1,700 32865 1:26 PM 53,5 32.6 1,700 33104 (1707 gpm) 1:27 PM surging x 5 1:32 PM 55.5 34.6 .1,800 33168 1:46 PM 58.3 36.4 1,800 33433 (1892 gpm) 1:47 PM surging x 5 1:57 PM 59,9 37.9 2,000 33477 (1993 gpm) 2:06 PM 60.8 38.9 2,000 33776 micas + coarse sand 2:10PM .surging x 10? 2:13 PM 42.4 20.5 1,000 33822 2:28 PM 42.3 20.4 1,000 tr 33979 (1047 gpm) 2:30 PM surging x 5 2:35 PM 43.0 21.1 1,100 34022. 2:53 PM 43.8 21.9 1,100 tr 34231 (1161 gpm) 2:54 PM surging X 5 2:58 PM 44.0 22,1 1,200 tr 34263 3:16 PM 45.7 23.8 1,200 34484 (1228 gpm) 3:18PM surging x 5 3:22 PM 46.1 24.2 • 1,300 tr 34532 3:41 PM 45.9 24.0 1,300 34783 (1321 gpm) 3:46 PM .surging x 5 4:01 PM 46.4 24.5 1,400 tr 34815 4:02 PM 47.8 25.9 1,400 35028 (1420 gpm) 4:23 PM surging x 5 4:24 PM 48.9 27.0 1,500 35069 4:29 PM 50.6 28.7 1,500 tr 35326 (1512 gpm) 4:47 PM surging X 5 4:48 PM 50.9 29,0 1,600 35384 4:51 PM 51.8 29.9 1,600 tr 35671 (1688 gpm) 5:01 PM surging X 5 •• 5:04 PM 53.9 32,0 1,700 35700 5:06 PM 26.0 4.1 1,700 tr 35871 (1710 gpm) 31-Aug-04 L-3 GEOSCIENCE Support Services, Inc. Tetra Tcch/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix L GEOSCIENCE Support Services, Inc. Ground Water Resources Development — TEL: (909)920-0707 PUMPING TEST DATA FAX: (909) 920-0403 Test Date: ll-Feb-04 Well Name/Number: Desalter Test Well DA"WI/PW9 Circle Well Type: CPumping!!) Observation (r = ft) Circle Test Type; Step Drawdown Constant Rate Recovery ^Development]^ Static Water Level Depth: 21.90 ft below RP Reference Point Elevation: -i- 2.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] fga'] 35947 pump off 31-Aug-04 L-4 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix L GEOSCIENCE Support Sei-vices, Inc. Ground Water Resources Development -::== TEL: (909)920-0707 PUMPING TEST DATA FAX: (909) 920-0403 Test Date; l2-Feb-04 Well Name/Number: Desalter Test Well D/TW1/PW9 Circle Weil Type: C ^Pumpin^ Observation (r = ft) Circle Test Type: Step Drawdown Constant Rate Recovery CpevelopmenP^ Static Water Level Depth: 21.90 ft below RP Reference Point Elevation: + 2.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content Remarks and Other Data Day [min] [minj [ft] [ft] [gpm] [ppm] [gal] 7:30 AM 21.9 0.0 35947 7:36 AM startup 7:39 AM 38.9 17,0 1,000 35961 7:59 AM 40.9 19.0 1,000 tr 36180 (1095 gpm) 8:00 AM surging x 6 8:03 AM 1,500 36208 8:21 AM 48.2 26.3 1,500 tr 36481 (1517 gpm) 8:22 AM surging x 6 8:26 AM 59.0 37.1 2,000 36526 8:42 AM 59.9 38.0 2,000 36857 (2069 gpm) 8:43 AM surging x 6 8:47 AM 59.4 37.5 2,000 36898 9:04 AM 61.0 39.1 2,000 372249 (2065 gpm) 9:05 AM surging x 6 9:09 AM 1,000 37287 9:23 AM 41.2 19.3 1,000 tr 37428 (1007 gpm) 9:24 AM surging X 6 9:27 AM 47.0 25.1 1,500 37449 9:47 AM 48.9 27.0 1,500 tr 37749 (1500 gpm) 9:48 AM surging x 6 9:51 AM 58.2 36,3 2,000 37774 10:06 AM 61.0 39.1 2,000 tr 38083 (2060 gpm) 10:07 AM surging x 5 10; 10 AM 1,000 38124 10:28 AM 42.0 20.1 1,000 tr 38324 (lill gpm) 10:29 AM .surging x 5 10:33 AM 1,500 38352 10:48 AM 49.4 27.5 1,500 tr 38579 (1513 gpm) 10:49 AM surging x 5 10:53 AM 2,000 38618 11:11 AM 62.2 40.3 2,000 38990 (2067 gpm) 11:12AM surging x 5 11:15 AM 1,000 39010 11:33 AM 44.0 22.1 1,000 tr 39215 (1139 gpm) 31-Aug-04 L-5 GEOSCIENCE Support Services, Inc. Telra Tech/San Diego County Water Authority Geohydrologic Investigation - Lowcr San Luis Rey River Valley Appendix L GEOSCIENCE Support Services, Inc. Ground Water Resources Development —--^ — TEL: (909)920-0707 PUMPING TEST DATA FAX: (909) 920-0403 Test Date: 12-Feb-04 Wel! Name/Number: Desalter Test Well Dn'Wl/PW9 Circle Well Type: CPumping^ Observation (r = ft) Circle Test Type: Step Drawdown Constant Rate Recovery <Clpe vel opmenr^ Static Water Level Depth: 21.90 ft below RP Reference Point Elevation: -i- 2.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content Remarks and Other Data Day [min] [min] fftl [ft] fgpm] [ppm] fgal] 11:34 AM surging x 5 11:37 AM 1,500 39240 11:56 AM 50.2 28.3 1,500 tr 39532 (1537 gpm) 11:57 AM surging x 5 11:59 AM 2,000 39549 12:16 PM 61.9 40.0 2,000 39900 (2065 gpm) 12:18 PM surging X 5 12:22 PM 1,000 39968 12:38 PM 42.1 20,2 1,000 tr 40145 (1106 gpm) 12:42 PM surging X 5 12:44 PM 1,500 40184 1:02 PM 50.3 28.4 1,500 tr 40448 (1467 gpm) 1:03 PM surging x 5 1 ;07 PM 2,000 40494 1:35 PM 62.4 40.5 2,000 41070 (2057 gpm) 1:37 PM surging x 5 1:40 PM 1,000 41115 1:57 PM 42.1 20.2 1,000 tr 41299 (1083 gpm) 1:58 PM surging x 5 2:00 PM 1,500 41310 2:16PM 50.6 28.7 1,500 tr 41546 (1475 gpm) 2:17 PM surging x 5 2:20 PM 1,200 41565 2:36 PM 45.9 24.0 1,200 tr 41760 (1219 gpm) 2:37 PM .surging x 5 2:40 PM . 1,600 41786 2:59 PM 55.5 33.6 1,600 tr 42111 (1711 gpm) 3:00 PM surging X 5 3:03 PM 1,800 42140 3:18PM 59.0 37.1 1,800 tr 42420 (2000 gpm) 3:20 PM surging x 5 3:22 PM 1,150 42444 3:37 PM 45.6 23.7 1,150 tr 42622 (1187 gpm) 3:38 PM surging x 5 31-Aug-04 L-6 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix L GEOSCIENCE Suppoit Services, Inc. Ground Water Resources Development TEL; (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date: 12-Feb-04 Well Name/Number: Desalter Test Well D/TW 1/PW9 C^mpin^ Circle Well Type; Circle Test Type: Step Drawdown Observation (r = Constant Rate ft) Recovery C^Dey e! opmenT^ Static Water Level Depth; 21.90 ft below RP Reference Point Elevation: + 2.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Tolal Water down Rate Content Remarks and Other Data Day [min] [min] [ft] [ft] [gpm] [ppm] [gal] 3:41 PM 1,350 42646 4:02 PM 49.0 27.1 1,350 tr 42937 (1388 gpm) 4:03 PM surging x 5 4:07 PM 1,600 42979 4:24 PM 53.3 31.4 1,600 tr 43250 (1594 gpm) 4:25 PM surging X 5 4:29 PM 2,000 43298 4:55 PM 62.8 40.9 2,000 tr 43829 (2213 gpm) 4:57 PM 43882 pump off 31-Aug-04 L-7 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix L GEOSCIENCE Support Services, Inc. Ground Water Resources Development ---^ ^ TEL: (909)920-0707 PUMPING TEST DATA FAX: (909) 920-0403 Test Date: 13-Feb-04 Well Name/Number; Desalter Test Well D/TW1/PW9 Circle Well Type: CPumpin^ Observation (r'= ft) Circle Test Type; Step Drawdown Constant Rate Recovery C^DevelopmenT^Ii^ Static Water Level Depth: 21.90 ft below RP Reference Point Elevation; + 2.00 ft Time Time Time Depth to Draw-Pumping Sand Totalizer of Step Total Water down Rate Content Remarks and Other Data Day [min] [min] [ft] [ftl [gpm] [ppm] [gal] 7:36 AM 1,050 43896 7:52 AM 40.0 18.1 1,050 tr 44078 (1138 gpm) 7:53 AM surging x 3 7:55 AM 1,300 44100 8;06 AM-45.8 23.9 1,300 tr 44255 (1409 gpm) 8:08 AM surging X 5 8:12 AM 1,600 44316 8:30 AM 50.3 28.4 1,600 tr 44609 (1628 gpm) 8:31 AM surging x 5 8:33 AM 1,800 44627 8:57 AM 54.8 32.9 1,800 tr 45093 (1817 gpm) 8:58 AM surging x 5 9:01 AM 2,000 45095 9:20 AM 61.8 39.9 2;000 45488 (2068 gpm) 9:22 AM surging x 5 9:25 AM 1,000 45518 9:45 AM 40.4 18.5 1,000 tr 45733 (1008 gpm) 9:48 AM surging X 5 9:51 AM 1,200 45778 10:08 AM 46.0 24.1 1,200 tr 45995 (1276 gpm) 10:09 AM surging x 5 10:12 AM 1,400 46019 10:30 AM 50.0 28.1 1,400 tr 46288 (1494 gpm) 10:31 AM surging x 5 10:34 AM 1,600 46317 10:51 AM 53.5 31.6 1,600 tr 46607 (1706 gpm) 10:52 AM surging x 5 10:56 AM 1,800 46649 1 i: 11 AM 55.9 34.0 1,800 tr 46923 (1827 gpm) 11:12 AM surging x 5 11:16 AM 2,100 46968 11:33 AM 61,2 39.3 2,000 tr 47313 (2312 gpm) 11:34 AM surging x 5 11:38 AM 1,000 1 437348 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix L GEOSCIENCE Support Services, Inc. Ground Water Resources Development TEL: (909)920-0707 FAX: (909) 920-0403 PUMPING TEST DATA Test Date; 13-Feb-04 Well Name/Number: Desalter Test Well D/TW1/PW9 C^umpin^ Circle Well Type; Circle Test Type; Step Drawdown Observation (r = Constant Rate ft) Recovery C[DevelopmenP^ Static Water Level Depth: 21.90 ft below RP Reference Point Elevation: + 2.00 ft Time of Day Time Step [min] Time Total [min] Depth to Water [ft] Draw- down [ft] Pumping Rate [gpm] Sand Content [ppm] Totalizer [gal] Remarks and Other Data 11:58 AM 41.0 19.1 1,000 tr 47551 (1015 gpm) 11:59 AM .surging x 5 12:02 PM 1,200 47560 12:07 PM 44.2 22.3 1,200 tr 47622 Fuel truck arrives (1240 gpm) 12:15 PM 1,400 47632 12:36 PM 46.8 24.9 1,400 tr 47921 (1376 gpm) 12:37 PM suring X 5 12:39 PM 1,500 47937 12:56 PM 51.9 30.0 1,500 tr 48198 (1535 gpm) 12:57 PM surging x 5 1:00 PM 1,700 48225 1:20 PM 54.4 32.5 1,700 tr 48577 {1760 gpm) 1:21 PM suring x 5 1:24 PM 1,850 48601 1:48 PM 60.0 38.1 1,850 tr 49070 (1954 gpm) 1:49 PM surging x 5 1:53 PM 1,000 49103 2:06 PM 40.6 18.7 1,000 tr 19235 {1015 gpm) 2:07 PM surging x 5 2:11 PM 1,500 49265 2:33 PM 50.5 28.6 1.500 tr 49588 (1468 gpm) 2:36 PM 49634 Pump Off 31-Aug-04 L-9 GEOSCIENCE Support Services, Inc. APPENDIX M Summary of Groundwater Elevations GEOSCIENCE Support Sen'ices, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] Site 1 lA/MWl 7/25/02 12.25 5,90 Site 1 lA/MWl 9/6/02 11.57 6,58 Site I lA/MWI 11/6/02 11.57 6,58 Site 1 lA/MWl 2/21/03 12.20 5.95 Site 1 lA/MWl 4/23/03 12.25 5,90 Site 1 lA/MWl 5/12/03 12.55 5,60 Site 1 lA/MWl 6/11/03 12.22 5.93 Site 1 lA/MWI 7/9/03 11.88 6.27 Site 1 lA/MWl 8/12/03 12.22 5.93 Site 1 lA/MWl 9/9/03 12.18 5.97 Site 1 lA/MWl 10/10/03 • 12.65 5.50 Site 1 lA/MWl 11/19/03 12,57 5,58 Site 1 lA/MWl 12/16/03 12.79 5.36 Site 1 1AA4W1 1/12/04 12.67 5.48 Site 1 lA/MWl 2/24/04 12.07 6.08 Site 1 lA/MWI 3/10/04 12.48 5.67 Site 1 IB/MW2 7/29/02 9.20 6,43 Site 1 1B/MW2 9/6/02 8.99 6,64 Site 1 1B/MW2 11/6/02 9.01 6,62 Site 1 1B/MW2 2/21/03 9.59 6.04 Site 1 1B/MW2 4/23/03 9.45 6,18 Site 1 1B/MW2 5/12/03 9.96 5.67 Site 1 1B/MW2 6/11/03 9.61 6.02 Site 1 1B/MW2 7/9/03 9,29 6.34 Site 1 1B/MW2 8/12/03 9.50 6.13 Site I 1B/MW2 9/9/03 9.60 6.03 Site 1 1B/MW2 10/10/03 9.95 5.68 Site 1 1B/MW2 11/19/03 9,97 5.66 Site 1 1B/MW2 12/16/03 10.20 5.43 Site 1 1B/MW2 1/12/04 10.10 5.53 Site 1 1B/MW2 2/24/04 9.49 6.14 Site 1 IB/MW2 3/10/04 9.86 5.77 Site 1 ICAIWl 7/29/02 9.10 6.65 Site 1 IC/TWl 9/6/02 , 9.11 6.64 Site 1 IC/TWl 11/6/02 9.13 6.62 Site 1 iCArw.i 2/21/03 9.70 6,05 Site 1 ICyTWl 4/23/03 9,55 6.20 31-Aug-04 M-l GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations # Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] Site 1 IC/TWl 5/12/03 10.07 5.68 Site 1 icnrwi 6/11/03 9.72 6.03 . Site 1 IC/TWl 7/9/03 9.42 6.33 Site 1 IC/TWl 8/12/03 9.60 6,15 Site 1 IC/TWl 9/9/03 9.71 6.04 Site 1 IC/TWl 10/10/03 10.05 5.70 Site 1 IC/TWl 11/19/03 10.09 5.66 Site 1 IC/TWl 12/16/03 10.31 5.44 Site 1 ICA'Wl 1/12/04 10.15 5.60 Site 1 IC/TWl 2/24/04 9.60 6.15 Site 1 IC/TWl 3/10/04 9.97 5.78 Site 2A 2A/B2/MW1-S 9/30/03 14.43 19.07 Site 2A 2A/B2/MW1-S 10/10/03 14.18 19.32 Site 2A 2A/B2/MWI-S 10/20/03 12.97 20.53 Site 2A 2A/B2/MW1-S 11/19/03 . 14.33 19.17 Site 2A 2A/B2/MW1-S 12/16/03 14.20 19.30 Site 2A 2A/B2/MW1-S T/12/04 11.60 21.90 Site 2A 2A/B2/MW1-S 2/17/04 12.27 21.23 Site 2A 2A/B2/MW1-S 2/24/04 13.20 20.30 Site 2A 2A/B2/MW1-S 3/10/04 13.20 20.30 Site 2A 2A/B2/MWI-D 9/30/03 11.06 22.46 Site 2A 2A/B2/MWI-D 10/10/03 11.98 2L54 Site 2A 2A/B2/MW1-D 10/20/03 11.96 21,56 Site 2A 2A/B2/MW1-D 11/19/03 12.15 21.37 Site 2A 2A/B2/MW1-D 12/16/03 12.24 21.28 Site 2A 2A/B2/MW1-D 1/12/04 11.75 21,77 Site 2A 2A/B2/MW1-D 2/17/04 11.96 21.56 Site 2A 2A/B2/MW1-D 2/24/04 11.95 21.57 Site 2A 2A/B2/MW1-D 3/10/04 11,84 21.68 Site 2B 2B/B1/MW1 9/6/02 22.66 n 25,80 Site 2B 2B/BI/MW1 11/6/02 23.77 24.69 Site 2B 2B/BI/MWI 2/21/03 22.88 25.58 Site 2B 2B/B1/MW1 4/23/03 22.18 26.28 Site 2B 2B/B1/MW1 5/12/03 23.00 25.46 Site 2B 2B/B1/MW1 6/11/03 25.18 23,28 Site 2B 2B/B1/MW1 7/9/03 26.98 21.48 Site 2B 2B/Bi/MWl S/I2/03 24.70 23.76 31-Aug-04 M-2 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] Site 2B 2B/BI/MW1 9/9/03 28.49 19.97 Site 2B 2B/B1/MW1 10/10/03 28.80 19.66 Site 2B 2B/B1/MW1 10/20/03 24.95 23.51 Site 2B 2B/B1/MW1 11/19/03 28.76 19.70 Site 2B 2B/B1/MW1 12/16/03 28.59 19,87 Site 2B 2B/BI/MW1 1/12/04 23.5! 24.95 Site 2B 2B/B1/MW1 2/17/04 24.90 23.56 Site 2B 2B/B1/MW1 2/24/04 27.34 21.12 Site 2B 2B/B1/MW1 3/10/04 27.50 20.96 Site 3B 3B/BI/MW1 • 7/25/02 20.95 31.87 Site 3B 3B/B1/MW1 7/26/02 21.00 31.82 Site 3B 3B/B1/MW1 9/6/02 20.95 31.87 Site 3B 3B/B1/MW1 11/6/02 21.25 31.57 Site 3B 3B/B1/MWI 2/21/03 20.38 32.44 Site 3B 3B/B1/MW1 4/23/03 19.57 33.25 Site 3B 3B/B1/MW1 5/12/03 • 19.89 32.93 Site 3B 3B/B1/MW1 6/11/03 20.22 32.60 Site 3B 3B/B1/MW1 7/9/03 20.65 32.17 Site 3B 3B/B1/MWI 8/12/03 22.13 30,69 Site 3B 3B/B1/MW! 9/9/03 21.91 30.91 Site 3B 3B/B1/MW1 10/10/03 22.24 30.58 Site 3B 3B/B1/MW1 10/20/03 22.60 30.22 Site 3B 3B/B1/MW1 11/19/03 22.43 30.39 Site 3B 3B/B1/MW1 12/16/03 22.32 30.50 Site 3B 3B/B1/MWI 1/12/04 21,86 30.96 Site 3B 3B/B1/MWI 2/17/04 21.76 31.06 Site 3B 3B/B1/MWI 2/24/04 21.55 31.27 Site 3B 3B/B1/MW1 3/10/04 21.35 31.47 Site 3B 3B/B2/MW2-S 9/30/03 20.36 30.41 Site 3B 3B/B2/MW2-S 10/10/03 21.19 29.58 Site 3B 3B/B2/MW2-S 10/20/03 21.17 29.60 Site 3B 3B/B2/MW2-S 11/19/03 20.36 30.41 Site 3B 3B/B2/MW2-S 12/16/03 21.30 29.47 Site 3B 3B/B2/MW2-S 1/12/04 20.05 30.72 Site 3B 3B/B2/MW2-S 2/17/04 • 20.70 30.07 Site 3B 3B/B2/MW2-S 2/24/04 20.45 30.32 Site 3B 3B/B2/MW2-S 3/10/04 20.23 30.54 31-Aug-04 M-3 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] Site 3B 3B/B2/MW2-D 9/30/03 . 21.18 29.64 Site 3B 3B/B2/MW2-D 10/10/03 19.96 30.86 Site 3B 3B/B2/MW2-D 10/20/03 19.98 30.84 Site 3B 3B/B2/MW2-D 11/19/03 21.36 29.46 Site 3B 3B/B2/MW2-D 12/16/03 20.04 30.78 Site 3B 3B/B2/MW2-D 1/12/04 19.73 31.09 Site 3B 3B/B2/MW2^D 2/17/04 19.60 31.22 Site 3B 3B/B2/MW2-D 2/24/04 19.39 31.43 Site 3B 3B/B2/MW2-D 3/10/04 19.15 31.67 Desalter D/B2/MWI-S 9/30/03 , 22.21 16.06 Desalter D/B2/MW1-S 10/10/03 22.12 16.15 Desalter D/B2/MW1-S 10/20/03 14.78 23.49 Desalter D/B2/MW1-S 11/19/03 22.15 16.12 Desalter D/B2/MW1-S 12/16/03 22.15 16.12 Desalter D/B2/MW1-S 1/12/04 13,43 24.84 Desalter D/B2/MW1-S 1/27/04 21.71 16.56 Desalter D/B2/MW1-S 2/16/04 14.25 24.02 Desalter D/B2/MW1-S 2/24/04 20,85 17.42 Desalter D/B2/MWI-S 3/10/04 21.00 17.27 Desalter D/B2/MW1-D 9/30/03 29,69 8.57 Desalter D/B2/MW1-D 10/10/03 29.03 9.23 Desalter D/B2/MW1-D 10/20/03 23.65 14.61 Desalter D/B2/MW1-D 11/19/03 30.17 8.09 Desalter D/B2/MW1-D 12/16/03 30.85 7.41 Desalter D/B2/MW1-D 1/12/04 20,55 17.71 Desalter D/B2/MWI-D 1/27/04 27.62 10.64 Desalter D/B2/MW1-D 2/16/04 15,97 22.29 Desalter D/B2/MW1-D 2/24/04 21.96 16.30 Desalter D/B2/MW1-D 3/10/04 22.16 16.10 Desalter OW-1 (40 East) 1/29/02 13.35 27.22 Desalter OW-1 (40 East) 2/26/02 13.35 27.22 Desalter OW-1 (40 East) 3/5/02 13,25 27.32 Desalter OW-1 (40 East) 4/12/02 13.15 27.42 Desalter OW-1 (40 East) 5/17/02 13.30 27.27 Desalter OW-1 (40 East) 6/18/02 13.55 27.02 Desalter OW-1 (40 East) 7/26/02 13,57 27.00 Desalter OW-1 (40 East) 8/16/02 13.35 27.22 31-Aug-04 M-4 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] Desalter OW-1 (40 East) 9/6/02 15.00 25.57 Desalter OW-1 (40 East) 10/22/02 21.20 19.37 Desalter 0W-! (40 East) 11/5/02 20.72 19.85 Desalter OW-1 (40 East) 12/10/02 16.90 23.67 Desaller OW-1 (40 East) 1/14/03 16.45 24.12 Desalter OW-1 (40 East) 2/18/03 15.64 24.93 Desalter OW-1 (40 East) 3/18/03 16.14 24.43 Desalter OW-1 (40 East) 4/23/03 15.23 25.34 Desalter OW-1 (40 East) 5/12/03 13,40 27.17 Desalter OW-1 (40 East) 6/11/03 13.59 26.98 Desalter OW-1 (40 East) 7/9/03 14.77 25.80 Desalter OW-1 (40 East) 8/12/03 15.51 25.06 Desalter OW-1 (40 East) 9/9/03 25.47 15.10 Desaller OW-1 (40 East) 10/10/03 25.95 14.62 Desalter OW-1 (40 East) 10/20/03 17.90 22.67 Desalter 0W-! (40 East) 11/19/03 26.0! 14.56 Desalter OW-1 (40 East) 12/16/03 26.50 14.07 Desalter OW-1 (40 East) 1/12/04 18.00 22.57 Desalter OW-1 (40 East) 2/17/04 17.9! 22.66 Desalter OW-I (40 East) 2/24/04 24.85 15.72 Desalter OW-1 (40 East) 3/10/04 24.80 15.77 Desalter OW-2 (140 West) 1/29/02 16.22 24.07 Desaller OW-2 (140 West) 2/26/02 16.70 23.59 Desalter OW-2 (140 West) 3/5/02 16.10 24.19 Desalter OW-2 (140 West) 4/12/02 16.00 24.29 Desalter OW-2 (140 West) 5/17/02 16.50 23,79 Desalter OW-2 (140 West) 6/18/02 16.42 23.87 Desalter OW-2 (140 West) 7/26/02 16.41 23.88 Desalter OW-2 (140 West) 8/16/02 16.25 24.04 Desalter OW-2 (140 West) 9/6/02 18.20 22.09 Desaller OW-2 (140 West) 10/22/02 24.70 15.59 Desalter OW-2 (140 West) 11/5/02 23.35 16.94 Desalter OW-2 (140 West) 12/10/02 20.20 20.09 Desalter OW-2 (140 West) 1/14/03 19.80 20,49 Desalter OW-2 (140 West) 2/18/03 18.99 21.3 Desalter OW-2 (140 West) 3/18/03 19.50 20,79 Desaller OW-2 (140 West) 4/23/03. 17.40 22.89 31-Aug-04 rvi-5 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] Desalter OW-2 (140 West) 5/12/03 15,45 24.84 Desalter OW-2 (140 West) 6/11/03 21.71 18.58 Desalter OW-2 (140 West) 7/9/03 23.90 16.39 Desalter OW-2 (140 West) 8/12/03 18.43 21.86 Desalter OW-2 (J40 West) 9/9/03 48.27 -7.98 Desalter OW-2 (140 West) 10/10/03 50.85 -10.56 • Desalter OW-2 (140 West) 10/20/03 16.5 23.79 Desalter OW-2 (140 West) 11/19/03 58.29 -18 Desaller OW-2 (140 West) 12/16/03 61.00 -20.71 Desaller OW-2 (140 West) 1/12/04 14.95 25.34 Desalter OW-2 (140 West) 2/17/04 15.84 24.45 . Desalter OW-2 (140 West) 2/24/04 60.39 -20.10 Desalter OW-2 (140 West) 3/10/04 61.75 -21.46 Desalter OW-1 Shallow 1/29/02 9.27 28.01 Desalter OW-1 Shallow 2/26/02 9.23 28.05 Desalter OW-1 Shallow 3/5/02 9.23 28.05 Desaller OW-1 Shallow 4/12/02 9.05 28.23 Desalter OW-1 Shallow 5/17/02 9.90 27.38 Desalter OW-1 Shallow 6/18/02 10.38 26.90 Desalter OW-1 Shallow 7/26/02 9.98 27.30 Desalter OW-1 Shallow 8/16/02 9.46 27,82 Desalter OW-1 Shallow 9/6/02 9.60 27.68 Desalter OW-1 Shallow 10/22/02 14.65 22.63 Desalter OW-1 Shallow 11/5/02 15.91 21.37 Desalter OW-1 Shallow 12/10/02 IL50 25.78 Desalter OW-1 Shallow 1/14/03 11.35 25.93 Desalter OW-1 Shallow 2/18/03 • 10.74 26.54 Desalter OW-1 Shallow 3/18/03 9.93 27.35 Desalter OW-1 Shallow 4/23/03 8.65 28.63 Desalter OW-1 Shallow 5/12/03 10.07 27.2! Desalter OW-1 Shallow 6/11/03 10.55 26.73 Desaller OW-1 Shallow 7/9/03 11.95 25.33 Desaller OW-1 Shallow 8/12/03 13.48 23.80 Desalter OW-1 Shallow 9/9/03 14.48 22.80 Desalter 0W-! Shallow 10/10/03 15.20 22.08 Desalter OW-1 Shallow 10/20/03 15.10 22,18 Desaller OW-1 Shallow 11/19/03 15.45 21.83 31-Aug-04 M-6 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] Desalter OW-1 Shallow 12/16/03 15.90 21.38 Desalter OW-1 Shallow 1/(2/04 14.70 22.58 Desalter OW-1 Shallow 2/17/04 13.74 23.54 Desalter OW-1 Shallow 2/24/04 13.68 • 23.60 Desaller OW-1 Shallow 3/10/04 13.97 23.31 Desaller OW-11 3/1/02 15.50 26.43 Desalter OW-ll 3/6/02 15.42 26.51 Desalter OW-11 6/10/02 15.50 26.43 Desalter OW-11 6/18/02 15.20 26.73 Desaller OW-11 9/6/02 22.38 19.55 Desaller OW-11 11/6/02 29.30 12.63 Desaller OW-11 2/21/03 35.75 6,18 Desalter OW-11 4/23/03 39.25 2.68 Desalter OW-11 5/12/03 17.64 24,29 Desalter OW-11 6/11/03 47.97 -6.04 Desalter OW-11 7/9/03 44.43 -2.50 Desalter OW-11 8/12/03 23.88 18.05 Desalter OW-11 9/9/03 49.82 -7.89 Desalter OW-11 10/10/03 50.05 -8.12 Desalter OW-11 10/20/03 24.10 17.83 Desaller OW-11 11/19/03 50.98 -9.05 Desaller OW-11 12/16/03 53.94 , -12.01 Desalter OW-11 1/12/04 19.92 22.01 Desalter OW-11 . 2/17/04 22.72 19.21 Desalter OW-11 2/24/04 46.98 -5.05 Desalter OW-11 3/10/04 45.74 -3.81 Site 7A 7A/B1/MW1 7/25/02 23,53 49.83 Site 7A 7A/B1/MW1 9/6/02 24.89 48.47 Site 7A 7 A/B 1/MWl 11/6/02 27.30 46.06 Site 7A 7A/B1/MW1 2/21/03 20.22 53.14 Site 7A 7A/B1/MWI 4/23/03 19.24 54.12 Site 7A 7A/B1/MW! 5/12/03 19.94 53.42 Site 7A 7A/B1/MW1 6/11/03 19.93 53.43 Site 7A 7A/BI/MW1 7/9/03 20.08 53.28 Site 7A 7A/B1/MW1 8/12/03 20.21 53,15 Site 7A 7A/B1/MW1 9/9/03 20.58 52.78 Site 7A 7 A/B 1/MWl 10/10/03 20.88 52,48 31-Aug-04 M-7 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] . Groundwater Elevation [ft amsl] Site 7A 7A/B1/MW1 11/19/03 20.19 53.17 Site 7A 7A/B1/MW1 12/16/03 20.01 53.35 Site 7A 7A/B1/MW1 1/12/04 19.88 53.48 Site 7A 7A/B1/MW1 2/24/04 19.31 54.05 Site 7A 7A/B1/MW1 3/10/04 19.42 53.94 Site lOA lOA/Bl/MWl 6/12/02 16,77 44.30 Site lOA lOAyBl/MWl 6/19/02 16.82 44.25 Site lOA lOA/BI/MWl 9/6/02 17.66 43.41 Site lOA lOA/Bl/MWl 11/6/02 18.25 42.82 Site lOA lOA/BI/MWl 2/21/03 16.88 44.19 Site lOA lOA/Bl/MWl 4/23/03 15.46 45.6! Site lOA lOA/Bl/MWI 5/12/03 15.40 45.67 Site lOA lOA/Bl/MWl 6/11/03 15.62 45.45 Site lOA lOA/Bl/MWl 7/9/03 15.81 45.26 Site lOA lOA/Bl/MWl 8/12/03 16.02 45.05 Site lOA lOA/Bl/MWl 9/9/03 16.37 44.70 Site lOA lOA/BI/MWI 10/10/03 16,61 44.46 Site lOA lOA/Bl/MWl 11/19/03 16.74 44.33 Site lOA lOA/Bl/MWl 12/16/03 16.64 44.43 Site I OA lOA/Bl/MWl 1/12/04 16.35 44.72 Site lOA lOA/Bl/MWl 2/24/04 15.98 45.09 Site lOA lOA/Bl/MWl 3/10/04 15.66 45,41 Site IIC lIC/BI/MWl-S 10/10/03 39.96 39.00 Site UC 11C/B1/MW1-S 10/20/03 40.01 38.95 Site ilC UC/Bl/MWTS 11/19/03 40.09 38.87 Site lie 11C/B1/MW1-S 12/16/03 40.2] 38.75 Site UC llC/Bl/MWI-S 1/12/04 40.05 38.91 Site UC llC/Bl/MWI-S 2/24/04 39.74 39.22 Site UC 11C/B1/MW1-S 3/10/04 39.53 39.43 Site UC 11C/B1/MW1-D 10/10/03 35.22 43.67 Site UC UC/BI/MWl-D 10/20/03 36.55 42.34 Site UC UC/BI/MWl-D 11/19/03 35.58 43.31 Site 11C IIC/BI/MWI-D 12/16/03 35.74 . 43.15 Site lie 11C/B1/MW1-D 1/12/04 35.56 43.33 Site UC 11C/B1/MW1-D 2/24/04 35.26 43.63 Site UC 11C/B1/MW1-D 3/10/04 35.03 43.86 Site 13A 13 A/B 1/MWl 7/24/02 10.24 60.48 31-Aug-04 M-8 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] Site 13A 13A/B1/MW1 9/6/02 13.35 57.37 Site 13A 13A/B1/MW] 11/6/02 16.80 53.92 Site 13A 13A/B1/MW1 2/21/03 5.39 65.33 , Site 13A 13A/B1/MW1 4/23/03 8.43 62.29 Site 13A 13A/B1/MW1 5/12/03 5.59 65.13 Site I3A 13A/B1/MWI 6/11/03 5.75 64.97 Site 13A 13/VBl/MWl 7/9/03 6.02 64.70 Site 13A 13A/B1/MWI 8/12/03 6.68 64.04 Site I3A I3A/B1/MW1 9/9/03 9.20 61.52 Site 13A 13A/B1/MW1 10/10/03 8.48 62.24 Site 13A 13A/B1/MW1 11/19/03 9.11 61.61 Site 13A 13 A/B 1/MWl 12/16/03 6.01 64.71 Site 13A , 13A/B1/MW1 1/12/04 8.80 61.92 Site 13A 13A/B1/MW1 2/24/04 5.20 65.52 Site I3A I3A/BI/MW1 3/10/04 5.63 65.09 Site 32 32/Bl/MWl 6/13/02 13.34 21.21 Site 32 32/Bl/MWl 6/19/02 13,28 21.27 Site 32 32/Bl/MWl 9/6/02 13,19 21.36 Site 32 32/Bl/MWl 11/6/02 13.82 20.73 Site 32 . 32/Bl/MWl 2/21/03 12.90 21.65 Site 32 32/Bl/MWl 4/23/03 12.31 22.24 Site 32 32/Bl/MWl 5/12/03 12.89 21.66 Site 32 32/Bl/MWl 6/11/03 14.41 - 20.14 Site 32 32/Bl/MWl 7/9/03 15,43 19.12 Site 32 32/Bl/MWl 8/12/03 14.20 20.35 Site 32 32/Bl/MWl 9/9/03 16.45 18.10 Site 32 32/Bl/MWl 10/10/03 16.67 17.88 Site 32 32/Bl/MWl 11/19/03 16.64 17.91 Site 32 32/Bl/MWl 12/16/03 16.58 17.97 Site 32 32/Bl/MWl 1/12/04 , 13.36 21.19 Site 32 32/Bl/MWl 2/17/04 14.21 20.34 Site 32 32/Bl/MWl 2/24/04 15.60 18.95 Site 32 32/Bl/MWl 3/10/04 15.61 18.94 OW-5 1/24/02 24.60 42,78 OW-5 2/11/02 24.35 43.03 OW-5 3/6/02 24.60 42.78 OW-5 5/17/02 24.43 42.95 31-Aug-04 M-9 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] OW-5 6/10/02 24.66 42.72 OW-5 6/18/02 24.81 42.57 OW-5 9/6/02 25.51 41.87 OW-5 11/6/02 25.94 41.44 OW-5 2/21/03 23.35 44.03 OW-5 4/23/03 22.66 44.72 OW-5 5/12/03 23.11 44.27 OW-5 6/11/03 23.51 43,87 OW-5 7/9/03 23.81 43.57 OW-5 8/12/03 24.26 43.12 OW-5 9/9/03 24.66 42.72 OW-5 10/10/03 24.50 42.88 OW-5 11/19/03 24.41 42.97 OW-5 12/16/03 24.15 43.23 OW-5 1/12/04 23.77 43.61 OW-5 2/24/04 22.95 44.43 OW-5 • 3/10/04 23.15 . 44.23 OW-6 1/24/02 24,93 53.13 OW-6 3/6/02 24.94 53.12 OW-6 5/17/02 24.87 53.19 OW-6 6/10/02 25.09 52.97 OW-6 6/18/02 24.93 53.13 OW-6 9/6/02 24.78 53.28 OW-6 11/6/02 33.00 45.06 OW-6 2/21/03 23.92 54.14 • OW-6 4/23/03 23.65 54.41 OW-6 5/12/03 24,95 53.11 OW-6 6/11/03 22.87 55.19 OW-6 7/9/03 23.09 54.97 OW-6 8/12/03 23.23 , 54.83 OW-6 9/9/03 23.52 54.54 OW-6 10/10/03 23.59 54.47 OW-6 11/19/03 22.73 55.33 OW-6 12/16/03 22.15 . 55.91 OW-6 1/12/04 22.15 55.91 OW-6 2/24/04 21.77 56.29 OW-6 3/10/04 22.22 55.84 31-Aug-04 M- 10 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary pf Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] OW-7 1/24/02 23.63 51.58 OW-7 3/6/02 23.42 51.79 OW-7 5/17/02 23.57 51.64 OW-7 6/10/02 23.77 51.44 OW-7 6/18/02 24.32 50.89 OW-7 9/6/02 27,48 47.73 OW-7 11/6/02 29,71 45.50 OW-7 2/21/03 22.60 52.61 OW-7 4/23/03 22.27 52.94 OW-7 5/12/03 23.56 51.65 OW-7 6/11/03 22.56 52.65 OW-7 7/9/03 22.71 52.50 OW-7 8/12/03 22.83 52.38 OW-7 9/9/03 23.19 52.02 OW-7 10/10/03 23.63 51.58 OW-7 11/19/03 22.71 52.50 OW-7 12/16/03 22.55 52,66 OW-7 1/12/04 • 22.40 52,81 OW-7 2/24/04 21.80 53.41 OW-7 3/10/04 22,02 53,19 OW-8 1/24/02 24.45 49.01 OW-8 3/6/02 22.52 50.94 OW-8 5/17/02 22.51 50.95 OW-8 6/10/02 23.00 50.46 OW-8 6/18/02 23.55 49.91 OW-8 9/6/02 26.28 47.18 OW-8 11/6/02 28.13 45.33 OW-8 2/21/03 21.63 51.83 OW-8 4/23/03 21.36 52.10 OW-8 5/12/03 21.56 51.90 OW-8 6/11/03 21.83 51.63 OW-8 7/9/03 21,97 51.49 OW-8 8/12/03 22.17 51.29 OW-8 9/9/03 22.72 50.74 OW-8 10/10/03 23.22 50.24 OW-8 11/19/03 22.01 51.45 OW-8 12/16/03 21.85 51.61 31-Aug-04 M- 11 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Appendix M Summary of Groundwater Elevations Site Name Well Name Date of Measurement Depth to Water [ft below RP] Groundwater Elevation [ft amsl] OW-8 1/12/04 21.70 51.76 OW-8 2/24/04 21.21 52.25 OW-8 3/10/04 21.42 52.04 OW-9 1/24/02 17.25 51.85 OW-9 2/11/02 17.07 52.03 OW-9 2/27/02 16.53 52.57 OW-9 3/6/02 17.28 51.82 OW-9 5/17/02 17.18 51.92 OW-9 6/10/02 17.50 51.60 OW-9 6/18/02 17.97 51.13 OW-9 9/6/02 20.58 48.52 OW-9 11/6/02 22.39 46.71 OW-9 2/21/03 16.60 52.50 OW-9 4/23/03 15.73 53.37 OW-9 5/12/03 16.07 53.03 OW-9 6/11/03 16.42 52.68 OW-9 7/9/03 16.38 52.72 OW-9 8/12/03 16.82 • 52.28 OW-9 9/9/03 17.17 51.93 OW-9 10/10/03 17.60 51,50 OW-9 11/19/03 16.62 52.48 OW-9 12/16/03 16.48 52.62 OW-9 1/12/04 18.20 50.90 OW-9 2/24/04 15.50 53.60 OW-9 3/10/04 15.79 53.31 Site 26/27 26/Bl/MWl-S 10/7/03 12.59 228.05 Site 26/27 26/Bl/MWl-D 10/7/03 . 12.59 228.05 31-Aug-04 M- 12 GEOSCIENCE Support Services, Inc. FIGURES GEOSCIENCE Support Services, Inc. TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY \ iS&t Rancho Santa Fe r J^/jfcVAs^P"- REGIONAL VIEW SAN LUIS REY RIVER WATERSHED R.4 W. 1 RJ W. R.JW K.3W. FTcjiarcdb)'. OWB Map Pioji Sialc Plane 198), ZoocV Figure 1 CIS_p™j\san_diep>_cwa_f irohydjDWtvrt_£roh)idrQ_fl-04 dpr TETRA TECH / SAN DIEGO COUNTV WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY Prepared by: DWB Map Prnjcclkm Stale Plane [983. Zone VI Sourcf of Data: Dcpanniemof Water E^cwjTCKCGTiHind^'aiM Basm BoundanctV LOWER SAN LUIS REY RIVER WATERSHED INVESTIGATION AREAS o EXPLANATION [nvcstigation Site Parcel Boundaiy Mission and Bonsall Groundwater Basin Boundaries San Luis Rey River Watershed Boundary City Freeway Stale Highway Surface Waler San Luis Rey River San Luis Rey River Tributaries Camp Pendleton Boundary GEOSCIENCE Figure 2 GlS_proj\iM_diejo_c:wa_EMhyHio^*<kM^En>hvi!ro_fi-0^ ^[K" TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REV RIVER VALLEY iMISSION BASIN INVESTIGATION SITES EXPLANATION I 11C I •; • Investigation Site •- ~ ,«i.'^Hx P^n^ei Boundary Map l^rqjccDDn: SUIT Plane LSg5,Zoac\T SouiuQ otDaia' Tcnarcclv Luc, (Aerial Pholc), 200i. TEuaTccb, Inc. (Fji^ling WcUs and Envc:4]g3iiOQ Silcs). 2003 Dcpaitmcm of Water RKOtirces (GiDmH^ftaicc Hasm Bo«ni!ari«), IW7 rJ0 5~r,H 2000 Exisling Wells and Boreholes © Borehole ^ Moniloring Well Production Well Test Well while line Mission Groundwater Basin Boundary GEOSOENCE Figure 3 GISjHDj^ dic£iJ_cwa_gMliydre*i:*a_geohydn>_a-r>4JTC TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY PrciHTcd by: DWB Map PiDjttlinn- SlaLc Plane mi. Zane VI sot Data: TcosTcch, Inc (Aerial Pbou), 2M2. TeiraTech. Inc (Kxi^linf Wells and Investiganon Sites), 2003. Depannvntof Waler Resources (QtoLiiiL]\^aierBa&in boundaries), 1997 BONSALL BASIN INVESTIGATION SITES EXPLANATION •f I - x>. bi'.'esligation Siie (*_,;. jj . Parcel Boimdary- Exisling Monitoring Well white line Bonsall Groundwater Basin Boundary 1000 SEOSCIENCE Figure 4 GlS_pnij\fian_dicEo c^ta jcoliydrrfidc»a_g«)hydj'j_8-04ipr TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY Prepareilhy: DWB Map E^jcctiDa: Slale Plane I9S3. ZoncV] GAGING STATIONS AND AVERAGE ANNUAL PRECIPITATION LOWER SAN LUIS REV RIVER WATERSHED A EXPLANATION Invesligaiion Siie parcel Boundaiy NOAA Precipitation Slalio Location USGS Gaging Station Location and Designation Mission and Bonsall Groundwater Basin Boundaries San Luia Rey River Walershed Boiindary Freeway Stale Highway j ~j Surface' San Luis Rey River San Luis Rey River Tribularies SEOSCIENCE Figure 5 ClS_prq| Wi_ilJf £Q_cwa_gcollydIo^sd;:w^_Ecohyll^fl_^^-04 apr TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEV MISSION BASIN GEOLOGIC MAP AND LOCATION OF GEOLOGIC CROSS-SECTIONS EXPLANATION Geologic Classifications Qal Tii |5Q Alluvium (Holocene) Unnamed Marine Terrace Deposits (Pleistocene) San Onofre Breccia (Miocene) La Jolla Group (Eocene) Bonsall Tonalite (Upper Cielaeeous) Fault - Solid Where Mapped at Surface Fault' Dotted Where Concealed Strike and Dip of Bedding Plane A' Geologic Cross-Section — (Sec Plate i) Investigation Site Parcel Boundary Eiiisdng Wells and Boreholes ® Bordiolp ^ Monitoring Well Production Weil Tesi Well 9 [18H02 O O Other Well! San Luis Rey River Watershed Boundary City Freeway Statt; Highway Surface Water San Luis Roy River San Luis Rey River Tnbutarics Prejaredby DWB Ma^ ProjccuoQ: Slate Plane 1963, Zone VI R.5 W. R_4 W. Source of Geology, Phy^tc^rapbic Boundaiy. and Faitfts" (Geology) LTSGS "DctaJcdGcnIjydriilogical InvcsugauonoriJic Lower SaiiLmsRnlR!vcTValley,Saii[)ieeo,CA'. 1985. (Smite and [Jip. and Faults] ZiDnyeLal, 1974 Tan and Kennedy. 1996. GEOSCIENCE 3000 Swivl BB»*t«i hit Figure 6 TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY Prepared by: DWB Map Projectioo: Stale Plane 19S3,Zotie VI MISSION BASIN BEDROCK ELEVATIONS (2003) EXPLANATION Bedrock Elevation (feet above mi -200 to-170 -170 to-140 -UOto-llO -llOto-SO -80 to -50 >-50 1 level) 7A/B1/MW1 Well Site Designation -75 Bedrock Elevation (feet above mean sea level) Exisling Wells 0 Monitoring Well 9 Production Well [J] Test Well ^^O^ Olher Wells Mission Gfound*'ater Basil Boundary San Luis Rey River Watershed Boimdary Freeway Stale Highway San Luis Rey River San Ljiis Rey River Tributaries GEOSCIENCE rirotBi*<x tinv Sotm. in. Figure 7 GlSJJro]^sm^^dic:go_cwa_6^^yd^^^a(k^wa_geo(lydlo_8-04 ap TETRA TECH / SAN DIEGO COUiNTV WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEY Prcparnlby: DWB Map Projecuon: Suic Plane l9S3,A>neVI R-5W R.4W. Source orUala Cily ol Oceanside. ami L'SGS. (Waler Ici-cl dau| 2003 2000 4000 Feel MISSION BASIN GROUNDWATER ELEVATIONS (2003) EXPLANATION 3Q Groundwater Elevation (2003) "" (feet above mean sea level) 3B/B1/MW1 30 ft Well Site Designation Groundwater Elevation (2003) {feet above mean sea level) Existing Wells Monilering Well 9 Production Well Test Weil o Oiha Well white line Mission Groundwater Basin Boundary GEOSCIENCE « CA uri! fm^lDM.^ I Figure 8 GiS_proj^*aii djcgo cw0_geoJiyilirffiilcwa_ETOhydTo_H-O4-apf TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REV RIVER VALLEY LOCATION OF UNDERGROUND STORAGE TANKS (UST'S) IN MISSION BASIN Underground Storage Tanks (UST*s) Silcs with Regional Water Quality Conmil Board Status Preliminary Site Assessment UndCTway Remedial Action Underway Case Closed v/hitc line Mission Groundwater Basin Boundary Freeway Slate Highway Sac Ltiis Rey River San Luis Rey River Tributaries Prepmdby: DWB Map Projcciinn: Stale Plane t9«3,ZoncVT Source of Dala: Bteional WalD (Jualiiy Conlrol Board. JIXH. Figure 9 GrSjnQj^iaan_£liegfl_cwm_Eeohydio'«k'AB_jc(*ydio_R'OJ-ApT Tetra Tech/San Diego County Water Authority Geohydroiogic Investigation - Lower San Luis Rey River Valley Figure 10 Exploratory Borehole Drilling Operation at Site 2A. View is to the northwest. 3I-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tecli/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 11 ir-i .a Soil Core Sample from 2A/B2 at 245 - 265 ft below ground surface. 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 12 Installation of 2-inch PVC casing for Monitoring Well 11C/B1/MW1-D 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 13 Monitoring Well llC/Bl/MWl 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 14 Completed Monitoring Well llC/Bl/MWl 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Test Well IC/TWl - Constant Rate Pumping Test 0.1 0,1 -- 0.2 -• 0.3 -- -f 0.4 - - I 0-5 + c: I 0.6 - cs 0.7 -- 0.8 -- 1 Static Water Level = 14.29 ft below reference point 0.9 -I- Test Date: 25-Feb-02 Q = 50 gpm Source of data: Tetra Tech, Inc. 31-Aug-04 Time Since Pumping Started, minutes 10 As = 0,31 T = 264Q/AS = 42,600 gpd / ft 100 1000 Recovery c GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 16 ''Jim-':.. • Desalter Test Well (D/TW1/PW9) Conductor Casing Installation. View is to the southwest on lO-Dec-2003 3I-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Wentworth Grain Size Class Desalter Test Well D/TW1/PW9 Mechanical Grading Analysis Composite Plot Sand Gravel 200 IIIO 0,1 Sieve Opening, mm 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 18 Desalter Test Well D/TW1/PW9 Spiral Weld 16-inch Stainless Steel Casing Installation (24-Jan-2004) 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 19 Borehole Drilling Bit (17,5-inch) and Reaming Bit (26-inch) for D/TW1/PW9 33-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/ San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 20 Desalter Test Well D/TW1/PW9 - Deviation Survey Plot North and South East and West Deviation from Vertical, in 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Desalter Test Well D/TW1/PW9 - Step Drawdown Test 10 -• 20 -• s 'fi ^ 30 fi es 40 -• 50 60 Static Water Level - 12.3 ft bgs, 14.29 ft below Reference Point t* = 1,440 minutes (time after start of step when incremental drawdowns are measured) Test Date: 16-Feb-04 :P—^ Step 1 Qi= 1,124 gpm 10 Steps Qg = 2,070 gpm 100 Time Since Pumping Started, min Incremental Drawdown Asi =21,40 ft 1,000 -I I I I L tn c 10,000 5 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Desalter Test Well D/TW1/PW9 - Specific Drawdown Plot 0,040 0,030 • • B a. ec o 0.020 CO a, tn 0,010 0.000 Test Dates: 16-Feb-04 (step drawdown test) 17 & 18-Feb-04 (constant rate test) Equation of Best-Fit Straight Line: y = 0.000002x +0.017 Data Point Obtained From Step Drawdown Test Formation Loss Coefficient B = 0.017 ft/gpm Data Point Obtained From Constant Rate Test Well Loss Coefficient C = 0.000002 ft/gpm^ 500 1,000 !,500 Discharge, Q, gpm 2,000 2,500 3,000 C (B ro to 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Desalter Test Well D/TW1/PW9 Specific Capacity and Well Efficiency Diagram c i o es Q 100 1,500 Discharge, Q, gpm u C s tii C ro 03 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Desalter Test Well D/TW1/PW9 (Pumping Well) 24 Hour Constant Rate Pumping Test 0 -r 10 -- 50" Static Water Level at the time pumping started = J3.94 feet below reference point Test Date: 17 lo 18-Feb-04 Q = 1,850 gpm T = 2640/As = 181,000 gpd/ft Increase Discharge Rate (11:00 p.m.) As = 2.7 ft Start of Flowmeter Survey • (7:03 a.m.) ( Recovery Pump Off 10 100 Time Since Pumping Started, min 1,000 10,000 CO c ro 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley > o u Si s u 10 -- 20 D/B2/MW1-S (Observation Well) 24 Hour Constant Rate Pumping Test Jacob's Straight Line AppUed To Recovery 15 4- t': time since pumping stopped Test Date: 18-Feb-04 Q= 1,850 gpm r=50ft. - to = 0,22 min = 0.0002 day 0.1 1.0 As ^ 3,2 ft T = 264Q/AS = 152,600 gpd/ft S = 0.3Tto/r^ = 0.004 10.0 Time Since Pumping Stopped (f), min 100.0 1,000.0 c CD IO 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley OW-2 (140 West) (Observation Well) 24 Hour Constant Rate Pumping Test Jacob's Straight Line Applied to Recovery 2 -- 4 -- es 10 t': time since pumping stopped Test Date: 18-Feb-04 Q= 1,850 gpm r = 290 ft • to= 1.8 min = 0.0012 day T = 264Q/AS = 162,800 gpd/ft S = 0.3Tto/r^ = 0.0007 -I t I ' ' ' _j I • • As = 3.0 ft 10 Time Since Pumping Stopped (f), min 100 1,000 c (D ro o 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 5 -- 10 -- 15 -- c I "i 20 + as 25 -- 30 -- 35 40 Test Date: 17 & 18-Feb-04 Q= 1,850 gpm ro ^,3,100 ft t= 1,000 min = 0.69 days 10 Desalter Well D/TW1/PW9 Distance Drawdown Plot To As = 7.1 ft • D/B2/MW1-S OW-11 PW-2 PW-3*. ^ PW-1 *OW-2(I40 West) 2A/B2/M^I-S • 2B/B1/MW1 32/Bl/MWl T = 528Q/AS = 137,600 gpd/ft S = 03Tt/ro^ = 0.003 100 Distance From Pumped Well, ft 1,000 10,000 c CD IO 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 28 Desalter Test Well D/TW1/PW9 - Flowmeter Survey 100-120 120-140 140-160 160-220 Estimated Percent of Flow From Interval, Expressed as Percent of 1,800 gpni 40 60 Cumulative Flow, percent 100 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tecti/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 10 -- •o 20 + rt 30 -- 40 Static Waler Level = 19.25 ft below reference point Test Date: 20 to 22-Oct-03 Q = 995 gpm As 31 1.6 ft 10 PW-3 (Pumping Well) 40 Hour Constant Rate Pumping Test T = 264Q/AS = 164,000 gpd/ft 100 Time Since Pumping Started, min 1,000 Recovery Pump Off 10,000 C —t (D ro to 3I-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 1 -- 2 -- 3 -- c o . •a 4 as 5 -- 6 -- 7 -- Static Water Level 19.82 feet below reference point Test Date: 20 to 23-Oct-03 Q = 995 gpm As= 1.5 ft f(r/B) = 2.3Si/As = 4.45 s, = 2.9 ft s, = 4.74ft Ko(r/B) = 4.38 (r/B) = 0,014 r = 217ft t,- =41.75 min ^0,029 day B= 15,500 ft PW-2 (Observation Well) 40 Hour Constant Rate Pumping Test T = 229Q/s„ Ko(r/B) = 211,000 gpd/ft S = (r/B) 0.27Tt, /r^ = 0.0005 K'/b' = T/7.48tf = 0.000 12/days 10 100 Time Since Pumping Started, min Pump Off 2400 min • • . I Recovery 1,000 10,000 c o u o 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley o C3 1 -- 2 3 - • 4 -- 5 -- 6 -- 7 -- Static Water Level 16.38 feet below reference point Test Date: 20 to 23-Oct-03 Q = 995 gpm As= 1.5 ft f(r/B) = 2.3s,7As = 4.21 Si = 2.75 ft s^ = 5.50ft Ko(r/B) = 4.13 (r/B) = 0,018 r= 130 ft t, = 12 min ^ 0.008 day ^ B = 382 ft OW-2 (140 West) (Observation Well) 40 Hour Constant Rate Pumping Test T = 229Q/s^ Ko(r/B) = 171,000 gpd/ft S = (r/B) 0.27Tt, /r^ = 0.0004 K'/b' = T/7.48B^ = 0.157/days As= 1.5 ft Recovery 1.0 10.0 100.0 Time Since Pumping Started, min 1,000,0 ,10.000.0 <£2 c CO 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley 1 -- 2 - c |3 as 4 -- Static Water Level = 14.72 feet below reference point Test Date: 20 to 23-Oct-03 Q = 995 gpm As^ 1,5 ft f(r/B) 2.3s,7As = 2.9 Si= 1.9 ft s„ = 3.85 ft Ko(r/B) = 2.43 (r/B) = 0.10 r = 370 ft t,- =38,5 min = 0.027 day B= 1,088 ft D/B2/MW1-S (Observation Well) 40 Hour Constant Rate Pumping Test As= 1.5 ft Inflection point = 1.9 ft T = 229Q/s„ Kn(r/B) = 144,000 gpd/ft S = (r/B) 0.27Tt, /r^ = 0.0008 K'/b' = T/7.48tf = 0.016/days 10 100 Time Since Pumping Started, min / Recovery Pump Off 2400 min 1,000 10,000 c -t (D CO IO 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley PW-2 (Observation Well) 40 Hour Constant Rate Pumping Test Calculated Recovery I -- 2 -- ;^3 + u > o es 3 S3 , U 5 6 -- 7 As= 1,7 ft t': time since pumping stopped to = 2.0 minutes = 0.0014 days Test Date: 22-Oct-03 Q = 995 gpm r = 217ft T = 264Q/AS = 154,500 gpd/ft S = 0.3 T to/r = 0.0014 10 100 Time Since Pumping Stopped {V), min 1,000 c CO CO 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley OW-2 (140 West) (Observation Well) 40 Hour Constant Rate Pumping Test Calculated Recovery 1 -- 2 -- ^ 3 + u > c u OJ a: 4 -- U 5 6 -- 7 -- t': time since pumping stopped to = 0.49 minutes = 0.0003 days Test Date: 22-Oct-03 Q = 995 gpm r= 130 ft As^ 1.85 ft T = 264Q/AS = 142,000 gpd/ft S = 0.3 T Vr^ = 0.0008 0.1 1.0 10.0 Time Since Pumping Stopped (f), min 100.0 tn 1,000,0 c (D CO 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley -1 to D/B2/MW1-S (Observation Well) 40 Hour Constant Rate Pumping Test Calculated Recovery u "a U 0 1 2 3 -- 4 -- t': time since pumping stopped . to = 0.79 minutes = 0.0005 days Test Date: 22-Oct-03 Q = 995 gpm r = 370 ft T = 264Q/AS = 153,000 gpd/ft S = 0.3 T to/r = 0.0008 As= 1.7 ft ' ' I L. 10 Time Since Pumping Stopped (f), min 100 tn 1,000 c <D CO Ul 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrolic Investigation - Lower San Luis Rey River Valley 2 -- 4 -- i 6 o •a PW-3 (Pumping Well) Distance Drawdown Plot 10 2A/B2/MWI-S • / llC/BI/MWl-S Test Date: 20 to 23-Oct-03 -- Q = 995 gpm to = 4,766 ft - t= 1,000 min = 0.69 days --As = 3.3 ft D/B2/MW1-S -^y"^ PW-2 w -z • (140 WesO -- . T = 528Q/AS = 159,000 gpd/ft S = 0.3Tt/ro^ = 0.0014 K'/b' = (1.94xl0"'^)T/rfl^ = 0.001/days 1 1 1 1 r r 1 1 100 Distance From Pumped Well, ft 1,000 10,000 c <!> CO 31-Aug-04 GEOSCIENCE Support Services, Inc. TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REY RIVER VALLEV EXTENT OF AQUITARD IN MISSION BASIN EXPLANATION , ' " " • Estimaied Laicra] Exient i n _ I of Aquitard (based on borehole lithology and geophysical iogsl InvestigMion Site Parcel Bouiidary Existing Wells and Boreholes 0 Borcholt 0 Momlonng Well 9 Prwluaion WeU 0 Tea Wetl white line Missioo Groundwater Basin Boundary Prepartii by: DWB Map Projccunn: SUIC Pl^ 1983. Zcos V] B.5 W. I R 4 W TdnTrch, Inc. (Atrial Phnio). 3002. TdiaTcfA. Enc. (Exisling W?[l& ind InvcMjf aEion Stlfs). 2iJQ^. GEOSCIENCE FMORTH l.OOO Figure 37 CI S_ptoi/saii_diep>_cwii_geoliydnysdcwa^cohyiln)_8 JM_rig37.nnd Telra Tech/San Diego County Water Authoritj' Geohydrologic Investigation - Lower San Luis Rey River Valley Hydrographs of OW-1 Shallow and OW-1 (40 East) 12/21/93 9/12/94 12/19/01 9/11/02 6/3/03 Tl IQ C (D U 03 31-Aug-04 GEOSCIENCE Support Services, tne. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lowcr San Luis Rey River Valley Hydrographs of OW-6, OW-7, OW8, and OW-9 ' 60 S 50 CB 'fi c 3 O u o '7. O-^3 O- Q Q (5. •CP Date 1 Q o. to X? (Q' c (D CJ CO 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - L.ower San Luis Rey River Valley Hydrographs of OW-1 (40 East), OW-2 (140 West) and OW-1 Shallow 10 2/23/02 6/25/02 10/26ffl3 Tl ta c -I CD •(^ o 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley as c 3 O o Desalter Test Well D/TW1/PW9 Zone Testing Groundwater Elevations in Alluvial and Bedrock Aquifers 60 1 Zone 1 (245-265 ft bgs) Ave. Q = 6 gpm Zone 2 (190-210 ft bgs) Ave. Q = 15 gpm Zone 3 (110-130 ft bgs) Ave. Q - 185 gpm -100 -1 12-Jan-04 13-Jan-04 14-Jan-04 15-Jan-04 16-Jan-04 17-Jan-04 Date/Time 18-Jan-04 19-Jan-04 20-Jan-04 a c —I <D Notes; D/B2/MW1 is located 50 ft from D/TW1/PW9. Data gaps represent the period during which zone testing did not occur. 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley OW-11 (Observation WeU) 40 Hour Constant Rate Pumping Test 0.0 1.0 o aa 2.0 3.0 -I Static Water Levei 22.55 feet below reference point Test Date: 20 to 23-Oct-03 Q = 995 gpm r= 195 ft tn c 10,000(5 ro 10 100 1,000 Time, min 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley D/B2/MW1-S and D/B2/MW1-D (Observation Wells) 40 Hour Constant Rate Pumping Test 10 100 Time Since Pumping Started, min 1,000 10,000 •n <n c 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/ San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 44 Trilinear Diagram Mission Basin Alluvial Aquifer Groundwater This diagram shows differences in water type between wells screened in the alluvial aquifer. The water does not show any prominent water type, but is relatively enriched in chloride relative to other anions. D/B2 93 ft bgs PW-5 65-130 ft bgs PW-4 65-130 ft bgs 25 PW-3 100-142 ft bgs D/B2/MW1-S, 100-220 ft bgs D/TW1/PW9 100-220 ft bgs D/TWl/PW9-Zone3 110-130 ft bgs 2A/B2/MW1-S 25-90 ft bgs JOTWl 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/ San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 45 Trilinear Diagram Mission Basin Bedrock Aquifer Groundwater This diagram shows differences in water type between wells screened in the bedrock aquifer. The waler is sodium chloride type. D/B2/MW1-D 210-300 ft bgs D/TW1/PW9 Zone 2 190-210 ft bgs 11C/B1/MW1-D 300-410 ft bgs 3B/B2/MW2-S 170-300 ft bgs 2A/B2/MW1-D 210-300 ft bgs 3B/B2/MW2-D 400-440 ft bgs 11C/B1/MW1-S 180-250 ft bgs DmVl/PW9-Zone I 245-265 ft bgs 31-Aug-04 GEOSCIENCE Support Services, Inc. G IS_ ]mJj^san_^JiCE•_c^a jcf^ydro^sdcwa j«ihy<1iO^K-04 jpT TETRA TECH / SAN DIEGO COUNTY WATER AUTHORITY GEOHYDROLOGIC INVESTIGATION - LOWER SAN LUIS REV RIVER VALLEY Frcpaitdby: DWB Map PiojcctjorL Suit Plaacl^Ei.ZoncVl 0 2000 4000 Feci ESTIMATED UNSATURATED ALLUVIAL THICKNESS IN MISSION BASIN EXPLANATION Unsalutalcd AlluvLal Thickness (ft) I I 0-5 [ I 5-10' \ ••Wl\ 10-15 20-25 Based on water level data collected up to October 2003 and US Geological Survey 3O-meler digital elevation model 7A/B1/MW1 Well Sue Designation 24 Unsaturated Alluvial Thickness (ft) Existing Wells ProdiKlion Well Test WtLI 9 Mission Groundwater Basin Boundary San Luis Rey River Watershed Boundaiy Freeway Stale Highway San Luis Rey River San Luis Rey Rivcr Tributarie GEOSCIENCE Figure 47 GiS_p[oi^iaa_dicgo_cwa_^cohTdlfl^5dc»fl £cfihydro_*i-04 apr Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Figure 48 Trilinear Diagram Bonsall Basin Alluvial Aquifer Groundwater This diagram shows the water type of groundwater in the alluvial aquifer at Site 26/27. The water does not show any prominent water type, but is relatively enriched in chloride relative to other anions. 31-Aug-04 GEOSCIENCE Support Services, Inc. t t lilh i""uiillt t . . I. i * 1 t 1 i i * i"T"i In I OODGD IJ II'MMII ' ij "iii i 1! I iM I i I 1 t i 1 t i t 1 1 ' Plate 1 rrrm rsca/sjn DISCO coutm WATIH Aurmiiinr GEOLOGIC CROSS SECTIONS A-A' AND B-B' Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Table 1 Summary of Monthly Evaporation Rates (in Inches) Month Lake O'Neill Station Month 1953 1954 January -2,21 February -4.57 March • 4,65 3.93 April 4.91 4.75 May 7.60 6,09 June 6.59 7,95 July 8.66 8,24 August 8.49 8.07 September 5.41 6.60 October • 5.08 5.16 • November 3.58 3,80 December 4.27 2,92 Source of Data: DPW Division ofWater Resources Bulletin No. 57, 1956 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tedi;San Diego Couniy Water Authorily Geohydrologic Invesligaiion - Lo\¥er San Luis Rey River Valley Table 2 Summary of Field Investigation Exploratory Boreholes Borelioles Situ ID Frnish Dale Ground Surfaci! in amsl] BorElinlc Diameter Iin] Tolal Deolh [ft bgs] Depth to Bedrock [fll Grab Samole Iflbgs] Core Interval [fl bgs] SimulProbe Samoles Ifl bg.s] it 1 lA 3O-Jan-02 16.32 3,125 230 212 NA 0-230 NA N 1 iB TBD 12.S 3,125 230 221 NA O-230 NA N 1 IC 24-Jan-02 . 12.92 4,5 240 222 0-240 NA NA Y 1 B.3 3-Feli-02 7.S6 3,125 140 115 NA 0-140 NA Y 1 B-4 5-Feb-02 i.'i.yg 3,125 90 71.5 NA 0-90 NA N l,\ Bl TBD 29.35 3.125 il8 lis NA 0-118 NA N l,\ B2 3-Sep-03~ 31.36 5 310 91 0-95 y.wio NA Y 2ii Bl 26-Feb-02 48,46 3.125 130. 121 NA • 0-130 NA N 3B Bl 7-Mar-02 49.4 3,125 107 98.5 NA 0-107 NA N 3B B2 li-Sep-03 48,94 5 450 99 0-100; 308-465 100-308 NA Y 30 Bl U-Mar-02 58.99 3,135 264 215,5 NA 0-264 NA N 7A Bl 20-Mar-02 73.36 3,125 170 161 NA 0-170 NA y 9\ Bl 24-Mar-02 57.78 3,125 124 114 NA 0-124 NA N lOA Bl l9-Ma[-02 61.07 3.125 190 153 NA 0-190 NA N II Bl 16-]sn-02 56,25 3.125 150 135 NA 0-150 NA N nc Bl 25-3ep-03 77,28 J .Wl )56 * 0-50; 172-503 50-172 NA Y 13 BI 15-Feb-02 80,42 3,125 166 146 NA 0-166 NA N I3A Bl 13-Fel)-02 67,72 3,125 135 53,5 NA 0-135 NA N 32 Bl 5-Mar-l)2 30,97 3,125 218 209 NA 0-218 NA N DvsalUr Bl 13-Aug-03 41 5 220 136 0-59 59-220 93 N DvsalUr B2 2i-Aug-03 36,34 5 422 141 0-60; 220-290 60-220; 290-423 NA Y DvsalUr TWl 9-Jan-04 TBD 17.5 300 141 0-300 NA NA Y 16/17 Bl 2-OC1-03 240.65 5 120 116 NA 0-120 NA Y bgs NA TBD •- Beliiw Gniund Surfiicc : Noi Applicable = To Be Dclermincd 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydroiogic Investigation - Lower San Luis Rey River Valley Summary of Field Investigation Monitoring and Test Wells Monitoring Wells Test Wells .2 Perforated Interval u. 01 ^ ffl c • ~ u l-l Site ID Reamed I Shallow Casing Deep Casing c i: 'vi u E a Slot Siz Top of Ca Elevatic Ground w; Elevalio Water Qual ianiple Colle g Reamed Dia. Blank Interval Perforated Interval Casing Typc/Dia. Slot Size Top of Ca Elevatic G round w; Elevatit Pumping Test? [in] [ft bgs) [fl bgs] [in] [in] [ft amsl] [ft amsl] [in] [ft bgs] [ft bgs] [in] [in] [ft amsl] [ft amsl] [Y/N] lA/MWI 3,125 40-150 NA 2-in, PVC 0,02 18.2 5,9 NA NA NA NA NA NA NA NA NA 1 IB/MW2 16 80-220 NA 4-in, PVC 0,08 15,6 6,43 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA icmvi 16 0-80; 220-230 80-220 6-in PVC/SS* 0-08 15.7 6.65 Y 2A MW! 10.5 25-90 210-300 2-in, PVC 0.02 33,5 19,07^/2 2.46* Il-Sep-03 NA NA NA NA NA NA NA NA , NA 2B MWl 3-125 90-120 NA 2-in. PVC O.OI 48,5 25,8 NA NA NA NA NA NA NA NA NA NA MWl 3-125 70-100 NA 2-in. PVC O.OI 52,8 31.87 NA NA NA NA NA NA NA NA NA NA 3B MW2 10,5 170-300 400^40 2-iti. PVC 0,02 50.8 30.41^/ 29,64* 26-Sep-03 NA NA NA NA NA NA NA NA NA 7A MWl 3-125 120-150 NA 2-iii- PVC 0,01 73.4 49,83 NA NA NA NA NA NA NA NA NA NA lOA MWl 3,125 130-170 NA 2-in. PVC 0,01 61.1 44.3 NA NA NA NA NA NA NA NA NA NA lie MWl 10.5 180-250 300-410 2-in. PVC 0,02 78,9 39,00^/ 43.67* 6-OCI-03 NA NA NA NA NA NA NA NA NA 13A MWl 3,125 25-30 NA 2-in, PVC 0,01 70,7 57,37 NA NA NA NA NA NA NA NA NA NA 32 MWl 3,125 180-210 NA 2-in, PVC 0.01 34,6 21,21 NA NA NA NA NA NA NA NA NA NA liter MWl 10.5 85-140 190-270 2-in, PVC 0.02 38,3 16,06Vx 8,5/ ll-Sep-03 NA NA NA NA NA NA NA NA NA a NA NA NA NA NA NA NA NA NA TW1/PW9 26 0-100; 220-240 100-220 16-in, SS 0.094 TBD -22 Y 26/27 MWl 10-5 20-50 85-110 2-in. PVC 0.02 240-6 228,05^7 228,0.5'* 7-Oct-03 NA NA NA NA NA NA NA NA NA Notes: bgs NA TBD : Below Ground Surface • Not Applicable To Be Determined IC/TWl contains a Type 304L stainless steel well screen. First measured groundwater elevation in completed well as reported by City of Oceanside (see Appendix N). Groundwater elevation in shallow casing. Groundwater elevation in deep casing. 0> (D 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Summary of Soil Physical Properties Data Boring Sample Depth [ft] Soil Type [USCS*] Moisture Content [% wt] Dry Density (pcf) Effective Confined Pressure (psi) Saturated Hydraulic Conductivity (cm/sec) Effective Porosity • (%) Init. Void Ratio 2A/B2 95-95.5 CL 22.5 96.9 ---0.736 2A/B2 145-146 SP 15 90,9 40 5,OOE-05 46.2 . - 2A/B2 241-242 SC 8 96,8 40 l.lOE-05 40.7 - 3B/B2 175-176 SM 8,8 96.1 40 2.20E-05 39,7 - 3B/B2 252-253 SM 12.3 93.1 40 7.50E-05 39,4 - IIC/BI 78-78.5 SP 20 87,1 42.6 - 3.40E-05 42 - nc/Bi 92-92.5 CL 21.7 101.7 ---0,656 D/B2 75-75,5 ML 33.3 79,9 ---1.1 D/B2 206-207 SM 10.1 94.9 40 2.80E-05 42.9 D/B2 401-402 SP/SM 11.6 105.4 40 6.30E-05 36.7 - * Unified Sol! Classification System (D 3i-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Table 5 Water Quality Analysis Summary Maximum Constituent Units Detection Limit Method Number Contaminant Level (MCL) General Physical Properties' * . *• -' ** Color Color unit 1 EPA 110.2 15* Odor Odor unit 1 EPA 140.1 3* pH pH unit NA EPA 9040B 6,5-8,5* Specific Conductance umhos/cm'' 1 EPA 120.1 900 Total Dissolved Solids (TDS) mg/L 10 EPA 160,1 500* Turbidity NTU' • 1 EPA 180,1 5 Inorganics • Alkalinity as CaCO, ma/L" 2 SM2320B Bicarbonate Alkalinity as CaCOi mg/L 2 SM2320B Bromide mg/L 0.5 EPA 300,0 Carbonate Alkalinity as CaCO-, mg/L 2 SM2320B Chloride mg/L 2 EPA 300.0 250* Chromium (VI) mg/L 0.001 EPA 7199 Fluoride (total) mg/L 0,5 EPA 300.0 2* Hardness (as CaCO^) mg/L 2 EPA 130.2 Hydroxide Alkalinity as CaC04 mg/L 2 SM2320B Nitrate as N mg/L 0.11 EPA 300,0 10 Sulfate mg/L 2 EPA 300,0 250* Metals Aluminum ug/L . 10 EPA 200,8 50 to 200* Arsenic ug/L 1 EPA 200,8 50 Barium ug/L 1 EPA 200,8 2000 Boron mg/L 0,05 EPA 200.7 Cadmium ug/L 1 EPA 200.8 5 Calcium mg/L 0,1 EPA 601 OB Copper ug/L 2 EPA 200.8 1000* Iron ue/L 10 EPA 200,8 300* Lithium mg/L 0.05 EPA 200,7 Maanesium ms/L 0.02 EPA 200,7 Manganese ug/L 1 EPA 200,8 50* Nickel ug/L 1 EPA 200.8 100 Potassium mg/L 0,5 EPA 601 OB Selenium ug/L 2 EPA 200.8 50 Silicon mg/L as Silica 0.11 EPA 200,7 Silver ug/L 1 EPA 200,8 100* Sodium mg/L 0,5 EPA 601 OB Zinc ug/L 20 EPA 200,8 5000* Miscellaneous' ' • ' • , I 1,2,3-Trichloropropane (123-TCP) ne/L' 5 SRL 524M-TCP Perch1orate ug/L 2 EPA 314.0 Surfactants fMBAS") me/L 0.1 EPA 425.1 0,5* Notes: ' nephelometric turbidity units ^ milligrams per liter ^ micromhos per centimeter squared picocuries per liter millivolts micrograms per liter ^ nanograms per liter * National Secondary Drinking Water Standard 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Summary of Geophysical Borehole Log Testing Borehole Number IC B.3 2A/B2 3B/B2 7A/B1 llC/Bl D/B2 26/27/Bl Total Depth of Borehole [ft bgs] 240 140 310 460 170 503 423 132 Bottom Logged Interval [ft bgs] 230 109 308 458 62 501 421 130 Borehole Diameter [inches] 4 4 5 5 4 5 5 5 Date Geophysical Borehole Log Performed 24-Jan-02 3-Feb-02 3-Sep-03 15-Sep-03 20-Mar-02 25-Sep-03 25-Aug-03 2-Oct-03 16-in / 24-in Resistivity X X X X X X x' X Spontaneous Potential (SP) X X X X X X X X Laterlog 3 X X X X X • X X X Guard Resistivity X X X X X X X X Gamma Ray X X X X X X X X Acoustic (sonic) X X X X X X Variable Density X X X X X X Porosity X X X X X X fi> CT O m 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Summary of Aquifer Zone Test Field Results - Desalter Test Well D/TW1/PW9 Zone Number Depth of Zone [ft bgs] Static Water Level [ft bgs] Pumping Water Level [ft bgs] Discharge Rate [gpm] Field TDS [ppm] Field Turbidity [NTU] Field pH [pH units] Field Water Temperature ["C] 1 245-265 14,28 167.4 3.9 395 9.79 7.1 20,7 2 190-210 64,32 141.9 11 373 8.56 7.4 17,6 3 110-130 19.4 40 210 1112 0.8 7.4 18,5 Notes: TDS ^ Total Dissolved Solids bgs = Below Ground Surface ppm = Parts Per Miiiion 0) CT (D 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authorily Geohydrologic Investigation - Lower San Luis Rey River Valley Summary of Well Completion Details Desalter Test Well D/TW1/PW9 General Information Owner Well Name; DA'WI/PW9 State Well Number To be determined Well Owner: San Diego County Water Authority Owner Address: 4677 Overland Avenue San Diego, Califomia 92123 Latitude: To be determined Longitude: To be determined Land Surface Elevation: To be detemuned Well Localion: Approximately 1,000 feet south-southwest o the end of Heritage Avenue, Oceanside, Califomia Hydologic Unit: Mission Unit of the Lower San Luis River Groundwater Basin Geologic Setting: Alluvium & Bedrock (Sandstone) Use of Water: Municipal Drilling Equipment Drilling Rig Type: Reverse Circulation Rotary Pilot Borehole Bit Size/Type: 17 1/2-inch/Tricone Reamed Borehole Bit Size: 26-inch Mud Reservoir Type: Above-Ground Tank Mud Additives: Drispac (polymer) Method of Cutting Recovery: Discharge at Shale Shaker Conductor Casing and Sanitary Seal Conductor Casing OD: 30-inch Wall Thickness: .VI 6-inch Casing Length: 50 feei Casing Material: ASTM A139 Grade B Steel Conductor Borehole Diameter: 42-tnch Start Date of Conductor Borehole: IO-Dec-03 Completion Date of Conductor Borehole: lO-Dec-03 Date Conductor Casing Set: lO-Dec-03 Annual Seal Depth: 50 feet Composition of Sanitary Seal: 10,5 Sack sand-cement slurry Date of Placement: lO-Dec-03 Witness of Seal Placement; San Diego County Borehole Drilling and Logging Pilot Borehole Diameter: 17 1/2-inch Start Date of Pilot Borehole: 7-Jan-04 Completion Date of Pilot Borehole: 9-Jan-04 Total Depth of Pilot Borehole: 302,5 feet Reamed Borehole Diameter: 26-inch Start Date of Borehole Reaming: 24-Jan-04 Completion Date of Borehole Reaming: 24-Jan-04 Total Depth of Reamed Borehole: 250 feet Geophysical Logs Run; 9-Jan-04 16" & 64" Normal Resistivity Laterolog Spontaneous Potential (SP) Gamma-Ray Acoustic (Sonic) Caliper (date) ,. Flowmeter (Spinner; date): 18-Feb-04 Casine , Screen, Filter Pack and Annular Seals Start Date of Casing and Screen Install: 24-Jan-04 Casing ID: 16-inch Casing Wall Thickness: 5/16-inch Casing Type: Roscoe Moss spirally welded Casing Material: Type 304L Stainle.sK Steeel Cased Intervals: 0-50, 220-240 ft Sounding Tube Size & Length: 2-inch Sch, 40 Type 304L stainless steel, 0-97 Gravel Feed Tube Size & Ungth: 3-inch ASTM A53. Grade B sieel. 0-57 ft Date of Completion of Casing & Screen Install: 25-Jan-04 Screen ID: 16-inch Screen Wall Thickness: 5/16-inch Screen Type: Ful-Flo Louvers with 0,094-inch openings Screen Material: Type 304L Stainless Steel Screened Intervals: 100-220 feet Completed Depdi; 240 feet Filter Pack: Custom Blend i/4-inch X 16 (50-250 ft) Mediod of Placement; Fluid circulation through tremie pipe Stan Date of Filter Pack Placement: 25-Jan-04 Completion Date of Filter Pack Placement: 25-Jan-04 Annual Seals; 0-50 feet (cement) Completion Date of Annular Seal Placement; 26-Jan-04 CT <D 03 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Table 9 Deviation Survey Data Desalter Test Well D/TW1/PW9 Depth [ft bgs] Total Departure [inches] Depth [ft bgs] North/South East/West 0 0 0 10 . 0 0 20 '0,0 -0.0 30 -0,0 -0.0 40 -0,0 -0.0 50 -0,1 -0.0 60 -0,1 -0.0 70 -0.1 -0,0 80 -0.2 -0,0 90 -0.2 -0,0 100 -0,3 -0,0 no -0.3 0 120 -0.3 0 130 -0,3 0.1 140 -0,3 0.1 150 -0,4 O.I 160 -0.4 0.1 170 -0.4 0.1 ' 180 -0.5 0,1 190 -0.6 0,1 200 -0.6 0,1 210 -0,7 0,1 220 -0,7 0.1 228 -0,8 0.1 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Summary of Aquifer Test Results - Desalter Test Well D/TW1/PW9 Well Well Type Aquifer Transmissivity' [gpd/ft] Hydraulic Conductivity^ [gpd/ft'] Storativity^ [Fraction] Leakance^ [1/day] Data Source Dmvi/pw9 Pumping Alluvium 181,000 1,508 NA NA Pumping Drawdown Data Dmvi/pw9 Pumping Alluvium 148,000 1,233 NA NA Recovery Data D/B2/MW1-S Monitoring Alluvium 174,500 1,454 NA NA -Pumping Drawdown Data D/B2/MW1-S Monitoring Alluvium 153,000 1,275 0.004 NA Recovery Data OW-2 (140 West) Monitoring Alluvium 203,500 1,696 NA NA Pumping Drawdown Data OW-2 (140 West) Monitoring Alluvium 162,800 1,357 0,0007 NA Recovery Data 2B/MW1 Monitoring Alluvium 188,000 • 1,567 0,0006 NA Pumping Drawdown Data 2B/MW1 Monitoring Alluvium 153,000 1,275 0.0006 NA Recovery Data Multiple Monitoring Alluvium 137,600 1,147 0,003 3.0 X lO'Vdays Distance Drawdown Data Notes: Transmissivity is the ability of an aquifer to transmit water. Transmissivity is the product of the hydraulic conductivity and the saturated aquifter thickness Hydraulic conductivity is the ability of an aquifer to transmit water per unit thickness of the aquifer. The aquifer hydraulic conductivity incorporates properties of both the fluid (kinematic viscosity) and medium (intrinsic perraeabliiity). Hydraulic conductivity is calculated by dividing the transmissivity of the aquifer by the saturated thickness of the aquifer. The estimated thickness of the alluvial aquifer at D/TWi/PW9 is 120 ft (based on the lithology as recorded in drilling logs at Storarivity is the volume of water that is released or added to storage per unit surface area of the aquifer per unit change in hydraulic head, Leakance is the ratio of the hydraulic conducrivity of the semi-confining layer (i,e, "leaky" layer) to the thickness ofthe layer. Vertical leakage (between aquifers) is the product of the leakance, area and hydraulic head difference (i.e. the difference between the head at the top and bottome of the leaky layer). Ql CT (D O 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Summary of Aquifer Test Results - City of Oceanside WeU PW-3 Well Well Type Aquifer Transmissivity' [gpd/ft] Hydraulic Conductivity"^ fapd/ft^l Storativity^ [Fraction] Leakance'* [1/day] Data Source PW-3 Pumping Alluvium 164,000 2,645 NA NA Pumping Drawdown Data PW-3 Pumping Alluvium 131,000 2,113 NA NA Recovery Data PW-2 Monitoring Alluvium 211,000 3,403 0.0005 0.00012 Pumping Drawdown Data PW-2 Monitoring Alluviiim 154,500. f 2,492 0,0014 NA Recovery Data OW-2 (140 West) Monitoring Alluvium 171,000 2,758 0.0004 0.157 Pumping Drawdown Data OW-2 (140 West) Monitoring Alluvium 142,000 2,290 0.0008 NA Recovery Data D/B2/MW1-S Monitoring Alluvium 144,000 2,322 0.0004 0.016 Pumping Drawdown Data D/B2/MW1-S Monitoring Alluvium 153,000 2,468 0.0008 NA Recovery Data Multiple Monitoring Alluvium 159,000 2,565 0.0014 0.0012 Distance Drawdown Data Notes: ' Transmissivity is the ability of an aquifer to transmit water. Transmissivity is the product of the hydraulic conductivity and the saturated aquifter thickness. ^ Hydraulic conductivity is the ability of an aquifer to transmit water per unit thickness of the aquifer. The aquifer hydraulic conductivity incorporates properties of both the fluid (kinematic viscosity) and medium (intrinsic permeablility). Hydraulic conductivity is calculated by dividing the transmissivity of the aquifer by the saturated thickness of the aquifer. The estimated thickness of the alluvial aquifer at PW-3 is 62 ft (based on the lithology as recorded in drilling logs at the Desalter Site). ^ Storativity is the volume of water that is released or added to storage per unit surface area of the aquifer per unit change in hydraulic head. Leakance is the ratio of the hydraulic conductivity of the semi-confining layer (i.e. "leaky" layer) lo the thickness of the layer. Vertical leakage (between aquifers) is the product of the leakance, area and hydraulic head difference (i.e. the difference between the,head at the top and bottome of the leaky layer). ^ Q) CT Q 31-Aug-04 GEOSCIENCE Support Services, Inc. Tetra Tech/San nicgo Cuunly Water Authorily Geohydrologic Investigation - IjOwer San Luis Rey River Valley Groundwater Analytical Data - Inorganics Well Name Interval Aquifer Date Sampled Bicarbonate ms/L Carbonate mg/L Alkalinity mc/l. Hydroxide mc/h Hardness as CaCOj mg/L Chloride ms/L Sulfate mg/L Surfactants (MBAS) me/L Nitrate-N mg/L Fluoride mg/L Bromide mg/L Chromium V( ma/L IGTWl 80-220' Deep Alluvial 15-Feb-02 330 ND 270 ND 740 670 380 0.23 0-2 NA NA NA 2A/B2/MW1-S 25-90" Shallow Alluvial 1 l-Sep-03 260 ND 260 ND 720 270 520 ND ND ND 1,4 ND 2A/B2/MW^D 210-300" Bedrock 1 l-Sep-03 100 ND 100 ND 120 560 170 ND 0,37 L3 3,1 • ND PW-l 100-160' Deep Alluvial 23-Sep-03 NA NA 260 . NA 474 386 413 NA ND 0-26 NA NA PW-2 100-180" Deep Alluvial /Bedrock 23-Sep-03 NA NA 250 NA 524 439 434 NA ND 041 NA NA PW-3 ,100-142" Deep Alluvial 23-Sep-03 NA NA 275 NA 559 527 430 NA ND 0,28 NA NA D/B2 93" bgs Deep Alluvial l8-Aug-03 310 ND 310 ND 800 290 510 NA 0.23 NA NA NA D/B2/MW1-S 85-140' Deep Alluvial I l-Sep-03 250 ND 250 ND 780 350 480 ND ND ND 1,9 ND D/B2/MW1-D 190-270' Bedrock ll-Sep-03 140 4,0 150 ND 84 92 83 ND 0-12 ND 0.51 ND D/rWl/PW9-Zone 1 245-265' Bedrock l3-Jan-04 150 4,0 160 ND 29 120 65 NA 0,17 NA NA NA D/rWI/PW9-Zone 2 190-210' Bedrock l5-Jan-04 !50 ND 150 'ND 140 89 60 NA ND NA NA NA D/rWl/PW9-Zone3 110-130' Deep Alluvial !9-JaTi-04 260 ND 260 ND 730 410 410 0,11 ND NA NA NA D/rwi/pw9 100-220' Deep Alluvial /Bedrock l8-Feh-04 340 ND NA ND 690 470 440 0.14 ND 0,23 NA ND 3B/B2/MW2-S 170-300' Bedrock 26-Sep-03 120 ND 120 ND 160 94 66 NA ND NA NA NA 3B/B2/MW2-D 400-440' Bedrock ll-Oci-03 220 4.0 220 ND 76 280 100 "NA ND NA NA NA llC/Bl/MWI-S 180-250' Bedrock 6-Oct-03 120 ND 120 ND 60 140 100 NA 1,7 NA NA NA IIC/Bl/MWI-D 300-410' Bedrock 6-Oct-03 340 ND 340 ND 84 240 100 NA ND NA NA NA PW^ 65-130' Shallow Alluvial 23-Sep-03 NA NA 305 NA 454 378 500 NA 2,33 0,34 NA NA PW-5 65-130' Shallow Alluvial 23-Sep-03 NA NA 340 NA 462 400 515 NA 3,22 0,36 NA NA 26/27/B IA1W I-S 20-50' Shallow Alluvial 7-Oct-03 270 ND 270 ND 760 300 • 380 NA 5.6 NA NA NA 26/27/B l/MWl-D 85-110' Deep Alluvial 7-Oc!-03 210 ND 210 ND 680 230 370 - NA 6-1 NA NA NA Q> (D ro Notes; ND - Consutueni not delected above the laboratory detection limit. NA - Not Analyzed mg/L= milligrams per liter 31-Aug-<V4 GEOSCIENCES Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Groundwater Analytical Data - Metals Well Name Interval Aquifer Date Sampled S 3 C s 3 Mg/L u '3 < Mg/L S .2 'C a ca Mg/L c o u o ta mg/L E S •a U Mg/L E _3 03 U mg/L u a. a o tJ mg/L s o u Mg/L S = mg/L E c ec as mg/L a BC S ca Mg/L u Z Mg/L E s as o a. mg/L E = *S "3 Mg/L e e u E« mg/L I- Mg/L S •3 o mg/L N Mg/L IC/TWl 80-220' Deep Alluvial 15-Feb-02 NA NA NA NA NA 180 ND 270 NA 71 480 NA 10 NA, NA-NA 340 30 2/VB2/MW1-S 25-90' Shallow Alluvial ll-Sep-03 4900 1.5 130 0.27 ND 180 5.6 3600 ND 45 2500 7 10 3.1 51 ND 280 70 2A/B2/MW1-D 210-300' Bedrock ll-Sep-03 4200 3.2 70 0,54 ND 40 4,7 3000 0,08 2.8 89 9.1 5.1 8.2 14 ND 430 1700 PW-1 100-160' Deep Alluvial 23-Sep-03 NA NA NA NA NA 190 NA 3500 NA 70.1 663 NA NA NA NA NA NA NA PW-2 100-180' Deep Alluvial /Bedrock 23-Sep-03 NA NA NA NA NA 210 NA 1490 NA 75.1 486 NA NA NA NA NA NA NA PW-3 100-142' Deep Alluvial 23-Sep-03 NA NA NA NA NA 224 NA 2220 NA 81,8 507 NA NA NA NA NA NA NA D/B2 93' bgs Deep Alluvial 18-Aiig-03 NA NA NA NA NA 220 NA NA NA NA NA NA 38 NA NA NA 250 NA D/B2/MW1-S 85-140' Deep Alluvial iI-Sep-03 280 1,2 160 0.25 ND 170 ND 1800 ND 67 620 1.2 10 2.7 33 ND 230 ND D/B2/MW1-D 190-270' Bedrock ll-Sep-03 1500 4.4 67 0.63 ND 28 ND 980 ND 2,4 58 ND 2.6 ND 32 ND 130 44 D/TWl/PW9-Zone 1 245-265' Bedrock 13-Jan-04 NA NA NA NA NA 8,80 NA 670 NA NA 15 NA 1.1 NA NA NA 160 NA D/TWl/PW9-Zone2 190-210' Bedrock I5-Jan-04 NA NA NA NA NA 25 NA ND NA NA 9,6 NA 1.6 NA NA NA 99 NA DA-Wl/PW9-Zone 3 110-130' Deep Alluvial 19-Jan-04 NA NA NA NA NA 170 NA 1400 NA NA 370 NA 11 NA NA NA 250 NA DA"W1/PW9 100-220' Deep Alluvial /Bedrock 18-Feb-04 ND ND 150 0.28 ND 170 4,2 2300 NA 63 460 2.1 10 8.1 NA ND 230 ND IU <D CO 31-Aug-04 Page 1 of 2 GEOSCIENCES Support Services, Inc. Tetra Tech/San Diego County Water Authority Geohydrologic Investigation - Lower San Luis Rey River Valley Groundwater Analytical Data - Metals Well Name Interval Aquifer Date Sampled E 3 S E = < Mg/I> u 'E at u < Mg/L E .2 'u ca n Mg/L 5 Ul o mg/L E 3 s TS as O Mg/L S 3 '0 "3 u mg/L u <u a a o U mg/L c 1 Mg/L E 3 la mg/L E 3 e 93 mg/L IU V c 03 en C 01 Mg/L <u .X u Z Mg/L E U5 CQ O a. mg/I. E 3 'S Ol "iJ Mg/L c o w mg/L u Oi _> Mg/L E 3 •S o tn mg/L C N Mg/L 3B/B2/MW2-S 170-300' Bedrock 26-Sep-03 NA NA NA NA NA 55 NA NA NA NA NA NA 3.7 NA NA NA 130 NA 3B/B2/MW2-D 400-440" Bedrock ll-Oct-03 640 NA NA NA NA 25 NA 500 NA NA 24 NA 2.1 NA NA NA 220 57 llC/Bl/MWI-S 180-250" Bedrock 6-OCI-03 7500 NA NA NA NA 20 NA 6400 NA NA 94 NA 3,6 NA NA NA 270 300 11C/B1/MW1-D 300-410' Bedrock 6-Oct-03 #### NA NA NA NA 27 NA #### NA NA 200 NA 3,7 NA NA NA 270 180 PW-4 65-130' Shallow Alluvial 23-Sep-03 NA NA NA NA NA 182 NA ND NA 99.6 402 NA NA NA NA NA NA NA PW-5 65-130' Shallow Alluvial 23-Sep-03 NA NA NA NA NA 185 NA ND NA 104 144 NA NA NA NA NA NA NA 26/27/Bl/MWl-S 20-50' Shallow Alluvial 7-Oct-03 NA NA NA NA NA 150 NA NA NA NA NA NA 4.7 NA NA NA 170 NA 26/27/B 1/MWl-D 85-110' Deep Alluvial 7^Oct-03 NA NA NA NA NA 180 NA NA NA NA NA NA 5.5 NA NA NA 200 NA Notes; ND = Constituent not detected above laboratory detection limit. NA = Not Analyzed. /ig/L = Micrograms per liter. mg/L = Milligrams per titer. fll (D CA3 31-Aug-04 Page 2 of 2 GEOSCIENCES Support Services, Inc. Tetra Tech/San Diego County Water Authority ^ Geohydrologic Investigation - Lower San Luis Rey River Valley Groundwater Analytical Data - Miscellaneous Compounds Well Name Interval Aquifer Date Sampled 123-TCP ne/L Color Color Unit Specific Conductance UH/L Odor T.O.N. pH pH units Perchlorate ua/l Total Dissolved Solids mfi/L Turbidity NTU IC/TWl 80-220' Deep Alluvial 15-Feb-02 NA NA 3020 NA 7,7 NA 1880 NA 2A/B2/MW1-S 25-90' Shallow Alluvial 11 -Sep-03 15 5 2400 ND 7,0 ND 1600 72 2A/B2/MW1-D 210-300'. Bedrock ll-Sep-03 ND ND 2400 4.0 8.12 ND 1400 49 PW-1 100-160' Deep Alluvial 23-Sep-03 NA 60 2190 3.0 7.14 NA 1460 32 PW-2 100-180' Deep Alluvial /RpHrnrk 23-Sep-03 NA 35 2312 1.0 7.38 NA 1550 16 FW-3 100-142' Deep Alluvial 23-Sep-03 NA 40 • 2575 1.0 7.28 NA 1690 23 D/B2 93' bgs Deep Alluvial 18-Aug-03 57 10 2300 ND 7.57 NA 1500 2500 D/B2/MW1-S 85-140' Deep Alluvial ll-Sep-03 140 28 2300 2.0 7.85 ND 1600 11 D/B2/MW1-D 190-270' Bedrock ll-Sep-03 ND ND 790 ND 8.13 ND 490 24 Dmvl/PW9-Zone 1 245-265' Bedrock 13-Jan-04 ND 10 770 ND 8.31 NA 480 11 Dmvl/PW9-Zone2 190-210' Bedrock 15-Jan-04 ND 19 760 ND 7,58 NA 450 21 DA'Wl/PW9-Zone3 110-130' Deep Alluvial 19Jan-04 230 28 2400 ND 7.07 NA 1600 24 D/TW1/PW9 100-220' Deep Alluvial /RpHrnfk 18-Feb-04 190 ND 2600 ND 7.34 ND 1500 35 3B/B2/MW2-S 170-300' Bedrock 26-Sep-03 NA 19 840 S.O 7.85 NA 520 66 3B/B2/MW2-D 400-440' Bedrock ll-Oct-03 NA 37* 1400 3.0* 8.28 NA 770 200* 11C/B1/MW1-S 180-250' Bedrock 6-Oct-03 NA NA 1300 NA 8.18 NA 820 NA UC/Bl/MWI-D . 300-410' Bedrock 6-Oct-03 NA NA 1200 NA 8.18 NA 830 NA PW-4 65-130' iihallow Alliivial 23-Sep-03 NA 4 2340 ND 7.49 NA 1600 0.1 PW-5 65-130' Shallow Alluvial 23-Sep-03 NA 4 2452 ND 7.54 NA' 1740 0,1 26/27/B 1/MWl-S 20-50' Shallow Alluvial 7-Oct-03 NA NA 2200 NA 7.46 NA 1500 NA 26/27/Bl/MWl-D 85-110' Deep Alluvial 7-Oct-03 NA NA 1900 NA 7.46 NA 1300 NA Notes: ND = Constituent not detected above the laboratory detection limit, NA - Not Analyzed ng/L = nanograms per liter pg/L = micrograms per liter mg/L = milligrams per liter * Results from sampled collected on 26-Sep-03. 01 CT 31-Aug-04 GEOSCIENCES Support Services, Inc.