HomeMy WebLinkAbout; Recycled Water Master Plan 2012 Part 1; Recycled Water Master Plan 2012 Part 1; 2012-01-12199 SOUTH LOS ROBLES AVENUE • SUITE 530 • PASADENA, CALIFORNIA 91101 • (626) 535-0180 • FAX (626) 535-0185 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/TOC_LOA
City of Carlsbad
RECYCLED WATER MASTER PLAN
January 2012
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City of Carlsbad Recycled Water Master Plan
TABLE OF CONTENTS
Page No.
EXECUTIVE SUMMARY
CHAPTER 1: INTRODUCTION
1.1 INTRODUCTION .................................................................................................... 1-1
1.2 PROJECT BACKGROUND .................................................................................... 1-1
1.3 STUDY AREA ........................................................................................................ 1-2 1.4 PROJECT OBJECTIVES ....................................................................................... 1-5
1.5 ACKNOWLEDGEMENTS....................................................................................... 1-5
1.6 REPORT ORGANIZATION .................................................................................... 1-6
CHAPTER 2: EXISTING RECYCLED WATE R SYSTEM
2.1 INTRODUCTION .................................................................................................... 2-1
2.2 SERVICE AREA ..................................................................................................... 2-1 2.3 EXISTING RECYCLED WATER SUPPLIES .......................................................... 2-1
2.4 EXISTING RECYCLED WATER CUSTOMERS .................................................... 2-5 2.5 RECYCLED WATER DISTRIBUTION SYSTEM .................................................... 2-7
2.5.1 Pipelines ..................................................................................................... 2-9
2.5.2 Pumping Stations...................................................................................... 2-11 2.5.3 Pressure Regulating Stations ................................................................... 2-12
2.5.4 Corintia Meter ........................................................................................... 2-14
2.5.5 Interconnections ....................................................................................... 2-14 2.5.6 Potable Water Supply Connections .......................................................... 2-14
2.5.7 System Operations ................................................................................... 2-14
2.6 ABANDONED FACILITIES .................................................................................. 2-16 2.7 KNOWN SYSTEM DEFICIENCIES ...................................................................... 2-20
2.7.1 Limited Supply from MWRF ...................................................................... 2-20
2.7.2 Water Quality Issues at Mahr Reservoir ................................................... 2-20 2.7.3 Calavera Pump Station ............................................................................. 2-20
2.7.4 Bressi Pump Station ................................................................................. 2-20
2.7.5 Gafner WRP ............................................................................................. 2-20
CHAPTER 3: RECYCLED WATER DEMANDS
3.1 INTRODUCTION .................................................................................................... 3-1 3.2 BACKGROUND ...................................................................................................... 3-1 3.3 HISTORICAL RECYCLED WATER DEMAND ....................................................... 3-3
3.3.1 Historical Demand Trends .......................................................................... 3-4 3.3.2 Existing Demand......................................................................................... 3-6 3.4 SEASONAL AND HOURLY PEAKING FACTORS ................................................ 3-9
3.4.1 Seasonal Peaking Factor............................................................................ 3-9 3.4.2 Hourly Peaking Factors and Diurnal Curves ............................................. 3-11
3.4.3 Summary of Peaking Factors ................................................................... 3-14
3.5 RECYCLED WATER DEMAND PROJECTIONS ................................................. 3-14 3.5.1 Methodology ............................................................................................. 3-15
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3.5.2 Potential Customers .................................................................................. 3-16 3.5.3 Near Term Demands ................................................................................. 3-25
3.5.4 Summary of Potential Customers ............................................................. 3-25
3.5.5 Customer Questionnaire ........................................................................... 3-35 3.5.6 Smaller Pickup Customers ........................................................................ 3-35
3.5.7 Demand Factors ........................................................................................ 3-36
3.5.8 New Developments ................................................................................... 3-37 3.5.9 Demand Summary .................................................................................... 3-41
CHAPTER 4: RECYCLED WATER SUPPLIES
4.1 INTRODUCTION .................................................................................................... 4-1 4.2 SUPPLY SOURCES ............................................................................................... 4-1
4.2.1 Existing Supply Sources ............................................................................. 4-1 4.2.2 Historical Supply Utilization ......................................................................... 4-2 4.2.3 Water Quality of Existing Supply Sources ................................................... 4-6
4.2.4 Supply from Seasonal Storage ................................................................... 4-9 4.2.5 Potential Future Supply Sources ............................................................... 4-11
4.3 SUPPLY REQUIREMENTS .................................................................................. 4-15
4.4 SUPPLY EVALUATION ........................................................................................ 4-17 4.4.1 Alternative 1 – Maximize Carlsbad WRF .................................................. 4-19
4.4.2 Alternative 2 - Maximize Meadowlark WRF .............................................. 4-21
4.4.3 Alternative 3 - Maximize Gafner WRP ...................................................... 4-22 4.4.4 Alternative 4 - Abandon Gafner WRP ....................................................... 4-24
4.4.5 Alternative 5 - Maximize Carlsbad WRF and Lake Calavera .................... 4-24
4.4.6 Alternative 6 - Utilize Shadowridge WRP .................................................. 4-26 4.4.7 Supply Evaluation Summary ..................................................................... 4-29
4.4.8 Unit Cost Comparison by Supply Source .................................................. 4-32
4.4.9 Potable Water Supplement Alternative ..................................................... 4-33 4.4.10 Recommended Supply Alternative ............................................................ 4-35
CHAPTER 5: RECYCLED WATER REGULATIONS
5.1 OVERVIEW OF REGULATING AGENCIES ........................................................... 5-1 5.2 FEDERAL REGULATIONS ..................................................................................... 5-1
5.3 STATE REGULATIONS .......................................................................................... 5-3 5.3.1 State Water Code ........................................................................................ 5-3
5.3.2 Code of Regulations – Title 22 .................................................................... 5-4
5.3.3 Code of Regulations – Title 17 .................................................................... 5-6 5.3.4 Draft Groundwater Recharge Legislation .................................................... 5-7
5.3.5 Statewide Recycled Water Policy ............................................................... 5-7
5.3.6 CDPH Guidelines ........................................................................................ 5-9 5.4 REGIONAL WATER QUALITY CONTROL BOARD ............................................. 5-10
5.5 LOCAL REGULATIONS ....................................................................................... 5-14
5.5.1 County of San Diego Regulations ............................................................. 5-14 5.5.2 District Mandatory Use Ordinance ............................................................ 5-15
5.5.3 District Regulations and Design Standards ............................................... 5-16
5.6 FUTURE REGULATORY DEVELOPMENTS ....................................................... 5-17 5.6.1 Groundwater Recharge ............................................................................. 5-17
5.6.2 Updates to the 2010 California Plumbing Code ........................................ 5-17
5.6.3 Constituents of Emerging Concern ........................................................... 5-18 5.6.4 Endocrine Disrupting Compounds ............................................................ 5-18
5.7 RECOMMENDATIONS ......................................................................................... 5-20
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CHAPTER 6: HYDRAULIC MODEL
6.1 HYDRAULIC MODELING OVERVIEW .................................................................. 6-1
6.1.1 Hydraulic Model Selection .......................................................................... 6-2
6.1.2 Previous Hydraulic Model ........................................................................... 6-2 6.2 EXISTING SYSTEM MODEL CREATION .............................................................. 6-2
6.2.1 Model Links................................................................................................. 6-4
6.2.2 Model Nodes .............................................................................................. 6-4 6.2.3 Demand Allocation...................................................................................... 6-4
6.2.4 Elevation Allocation .................................................................................... 6-5 6.2.5 Attribute Data Information ........................................................................... 6-5 6.2.6 Operational Controls ................................................................................... 6-7
6.3 EXISTING SYSTEM MODEL CALIBRATION ........................................................ 6-8 6.3.1 Field Data Gathering ................................................................................... 6-9 6.3.2 Extended Period Model Calibration .......................................................... 6-14
6.3.3 Extended Period Calibration Results ........................................................ 6-18 6.3.4 Water Quality Calibration .......................................................................... 6-19
6.3.5 Water Quality Calibration Results ............................................................. 6-23
6.4 FUTURE SYSTEM MODEL CREATION .............................................................. 6-24
CHAPTER 7: PLANNING AND EVALUATION CRITERIA
7.1 INTRODUCTION .................................................................................................... 7-1
7.2 SYSTEM PRESSURES.......................................................................................... 7-1 7.3 PIPELINE VELOCITIES AND HEAD LOSS ........................................................... 7-2
7.4 PIPELINE SIZING CRITERIA ................................................................................ 7-2
7.5 STORAGE SIZING CRITERIA ............................................................................... 7-3 7.5.1 Operational Storage.................................................................................... 7-3
7.5.2 Short-term Emergency Storage .................................................................. 7-5
7.5.3 Seasonal Storage ....................................................................................... 7-5 7.5.4 Summary .................................................................................................... 7-5
7.6 PUMP STATION SIZING CRITERIA ...................................................................... 7-5
7.7 SYSTEM RELIABILITY CRITERIA......................................................................... 7-6 7.8 SUMMARY PLANNING AND EVALUATION CRITERIA ........................................ 7-6
CHAPTER 8: EXISTING SYSTEM EVALUATION
8.1 HYDRAULIC ANALYSIS ........................................................................................ 8-1
8.1.1 Distribution System ..................................................................................... 8-1
8.2 STORAGE CAPACITY ANALYSIS ........................................................................ 8-9 8.3 PUMP STATION CAPACITY ANALYSIS ............................................................. 8-11
8.4 PUMPING EFFICIENCY AND ENERGY ANALYSIS ........................................... 8-12
8.5 WATER QUALITY ANALYSIS.............................................................................. 8-14 8.6 OPERATIONS AND MAINTENANCE .................................................................. 8-17
8.7 SUMMARY OF RECOMMENDATIONS ............................................................... 8-17
CHAPTER 9: FUTURE SYSTEM EVALUATION
9.1 INTRODUCTION .................................................................................................... 9-1
9.2 EVALUATION METHODOLOGY ........................................................................... 9-1
9.3 FUTURE SYSTEM EXPANSION EVALUATION ................................................... 9-2 9.3.1 Expansion Segments .................................................................................. 9-2
9.3.2 Other System Expansion Pipelines .......................................................... 9-15
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9.3.3 Alternatives Sizing and Cost Estimates .................................................... 9-17 9.3.4 Alternatives Ranking and Prioritization ..................................................... 9-19
9.3.5 Preferred Alternative - Phase III ................................................................ 9-20
9.3.6 Preferred Alternative - Build Out ............................................................... 9-22 9.3.7 Summary of Demand Projections ............................................................. 9-23
9.3.8 Supply Strategy ......................................................................................... 9-24
9.3.9 Utilization of Abandoned Assets ............................................................... 9-29 9.3.10 Redundancy .............................................................................................. 9-31
9.3.11 Storage Analysis ....................................................................................... 9-33 9.3.12 Pump Station Analysis .............................................................................. 9-36 9.4 SUMMARY OF FUTURE SYSTEM RECOMMENDATIONS ................................ 9-37
9.4.1 Distribution System ................................................................................... 9-37
CHAPTER 10: CAPITAL IMPROVEMENT PROGRAM
10.1 INTRODUCTION .................................................................................................. 10-1
10.2 COST ESTIMATING ASSUMPTIONS .................................................................. 10-1 10.2.1 Scope and Accuracy Range ...................................................................... 10-1
10.2.2 Markups and Contingency ........................................................................ 10-4
10.2.3 Unit Construction Costs ............................................................................ 10-5 10.2.4 Excluded Costs ......................................................................................... 10-6
10.3 SUMMARY OF RECOMMENDATIONS ............................................................... 10-7
10.3.1 Project Cost Estimates .............................................................................. 10-7 Project Phasing ................................................................................................... 10-11
10.4 CAPITAL IMPROVEMENT PROGRAM .............................................................. 10-12
10.4.1 CIP by Planning Phase ........................................................................... 10-12 10.4.2 CIP by Project Type ................................................................................ 10-15
10.4.3 Escalated CIP ......................................................................................... 10-15
LIST OF APPENDICES
APPENDIX A REFERENCES APPENDIX B SUPPLY ALTERNATIVES COST ESTIMATE DETAILS
APPENDIX C RECYCLED WATER CUSTOMER DATABASE APPENDIX D INTER-AGENCY AGREEMENTS
Mahr Reservoir Use Agreement
Leucadia County Water District Recycled Water Sales Agreement
Vallecitos Water District Recycled Water Sales Agreement
Vallecitos Water District Construction and Reconstruction of Water
Lines
MWD Agreement
APPENDIX E PERMITS AND REGULATIONS
Carlsbad WRF Master Reclamation Permit Gafner WRP Master Reclamation Permit and Addendums
Meadowlark WRF Master Reclamation Permit and Addendums
Ordinance 43 (Mandatory Use)
Ordinance 45 (Rates and Cross Connection Control Program)
APPENDIX F MODEL CALIBRATION DATA
Calibration Field Testing Plan
Calibration Data
Model Calibration Results
APPENDIX G MODEL MANUAL
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LIST OF TABLES
Page No.
Table 2.1 Recycled Water Supplies ............................................................................ 2-2
Table 2.2 Existing and Historical Recycled Water Demands ...................................... 2-5 Table 2.3 Largest Existing Recycled Water Customers ............................................. 2-6
Table 2.4 Summary of Facilities by Pressure Zone .................................................... 2-7
Table 2.5 Recycled Water Distribution System Pipelines ........................................... 2-9 Table 2.6 Pipelines by Installation Year and Material Type ...................................... 2-10
Table 2.7 Pumping Stations...................................................................................... 2-12 Table 2.8 Pressure Regulating Stations ................................................................... 2-13 Table 3.1 Phases of Distribution System Expansion .................................................. 3-1
Table 3.2 Historical Recycled Water Demands .......................................................... 3-3 Table 3.3 Largest Existing Recycled Water Customers ............................................. 3-5
Table 3.4 Historical Seasonal Peaking Factors .......................................................... 3-9
Table 3.5 Peaking Factors ........................................................................................ 3-14 Table 3.6 Customer Demand by Category ............................................................... 3-26
Table 3.7 Potential Customers ................................................................................. 3-27
Table 3.8 Water Demand Factors ............................................................................. 3-37 Table 3.9 New Development Demand Projections ................................................... 3-38
Table 3.10 Summary of Demand Projections ............................................................. 3-41
Table 3.11 Potential Build Out by Service Area .......................................................... 3-42 Table 3.12 Percentage of CMWD Demand Identified ................................................. 3-43
Table 3.13 Build-out Demand Summary ..................................................................... 3-43
Table 4.1 Recycled Water Supplies ............................................................................ 4-2 Table 4.2 Utilization of Recycled Water Supplies ....................................................... 4-3
Table 4.3 Water Quality Guidelines for Irrigation Use ................................................ 4-7
Table 4.4 Summary of Recycled Water Demands .................................................... 4-15 Table 4.5 Summary of Supply Requirements ........................................................... 4-16
Table 4.6 Supply Alternatives Summary ................................................................... 4-17
Table 4.7 Facilities Required for Expansion ............................................................. 4-18 Table 4.8 Alternatives for Expansion of Shadowridge WRP ..................................... 4-26
Table 4.9 Seasonal Supply Related to Shadowridge WRP ...................................... 4-27 Table 4.10 Preliminary Costs for Delivery from Shadowridge WRP ........................... 4-28
Table 4.11 Supply Alternatives Cost Comparison ...................................................... 4-29
Table 4.12 Supply Source Unit Cost Comparison ...................................................... 4-33 Table 4.13 Comparison of Potable Water Supplement with Alternative 1 .................. 4-35
Table 5.1 Roles of Agencies Involved in Recycled Water Use ................................... 5-2
Table 5.2 Summary of California Recycled Water Regulations .................................. 5-3 Table 5.3 Effluent Quality Standards for Unrestricted Use per Title 22 ...................... 5-4
Table 5.4 Approved Use Applications for Disinfected Tertiary Recycled Water ......... 5-5
Table 5.5 Basin Plan Groundwater Quality Objectives ............................................. 5-12 Table 5.6 Master Reclamation Permit Requirements ............................................... 5-13
Table 5.7 Potential Endocrine Disrupting Compounds ............................................. 5-19
Table 6.1 Summary of Demands by Pressure Zone ................................................... 6-5 Table 6.2 Junction Attribute Data Fields ..................................................................... 6-6
Table 6.3 Pipeline Attribute Data Fields ..................................................................... 6-6
Table 6.4 Operational Controls ................................................................................... 6-7 Table 6.5 Pressure Logger Locations ....................................................................... 6-10
Table 6.6 SCADA Data Availability ........................................................................... 6-13
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Table 6.7 Mass Balance for Calibration Day ............................................................. 6-15 Table 6.8 Pipeline Roughness Coefficients .............................................................. 6-17
Table 6.9 Water Quality Samples ............................................................................. 6-20
Table 6.10 Water Quality Calibration Results ............................................................. 6-23 Table 7.1 System Evaluation Criteria .......................................................................... 7-6
Table 8.1 System Evaluation Criteria .......................................................................... 8-2
Table 8.2 Pipeline Deficiency Locations ..................................................................... 8-7 Table 8.3 Pipeline Deficiencies Under Demand Conditions ........................................ 8-8
Table 8.4 Summary of Storage Facilities by Pressure Zone ....................................... 8-9
Table 8.5 Storage Capacity Evaluation ..................................................................... 8-10 Table 8.6 Booster Pump Station Capacity Evaluation .............................................. 8-11
Table 8.7 Power Usage for Hydro-pneumatic Zones ................................................ 8-13 Table 8.8 Summary of Facilities by Pressure Zone .................................................. 8-13 Table 8.9 Facility Inspection Criteria ......................................................................... 8-17
Table 9.1 Demands by Expansion Segment ............................................................... 9-3 Table 9.2 Expansion Segments for Serving Demands in VID (Segment 4) .............. 9-11
Table 9.3 Customer Demands in Expansion Segment 4 Alternatives ...................... 9-12
Table 9.4 Expansion Segments Preliminary Cost Estimates .................................... 9-18 Table 9.5 Expansion Segments Ranking .................................................................. 9-19
Table 9.6 Preferred Alternative – Phase III ............................................................... 9-21
Table 9.7 Preferred Alternative – Build-out Phase .................................................... 9-22 Table 9.8 Summary of Demands by Phase .............................................................. 9-23
Table 9.9 Potential Demand Outside CMWD’s Service Areas .................................. 9-24
Table 9.10 El Camino Real Abandoned Pipeline Alternative ...................................... 9-30 Table 9.11 TAP Connection Alternative ...................................................................... 9-31
Table 9.12 Redundancy Pipeline for Carlsbad Village ................................................ 9-32
Table 9.13 Analysis of Supply without Meadowlark WRF ........................................... 9-32 Table 9.14 Twin D Capacity Analysis .......................................................................... 9-33
Table 9.15 Storage Capacity Evaluation for Build-out ................................................ 9-34 Table 9.16 Storage Capacity Evaluation for Phase III ................................................ 9-36 Table 9.17 Ultimate Pump Station Capacity Analysis ................................................. 9-37
Table 9.18 Future System Recommendations ............................................................ 9-38 Table 10.1 Class Estimates ........................................................................................ 10-2 Table 10.2 General Cost Estimating Assumptions ...................................................... 10-5
Table 10.3 Unit Construction Cost .............................................................................. 10-5 Table 10.4 Detailed Project List .................................................................................. 10-8
Table 10.5 Capital Cost by Planning Phase and Project Type ................................. 10-12
Table 10.6 Timeline of Phasing ................................................................................. 10-15 Table 10.7 Escalated CIP by Planning Phase .......................................................... 10-16
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LIST OF FIGURES Page No.
Figure 1.1 Service Area of Water Districts ................................................................... 1-3 Figure 1.2 Service Area of Wastewater Districts ......................................................... 1-4
Figure 2.1 Existing Recycled Water System ................................................................ 2-3
Figure 2.2 Existing System Hydraulic Profile ............................................................... 2-8 Figure 2.3 Pipelines by Material Type ........................................................................ 2-10
Figure 2.4 Pipelines by Installation Year .................................................................... 2-11
Figure 2.5 Abandoned Potable Water System Facilities ............................................ 2-17 Figure 3.1 MWD Target and Ultimate Yield compared to Historical Demands ............ 3-2
Figure 3.2 Historical Recycled Water Demands .......................................................... 3-4 Figure 3.3 Existing Recycled Water Average Annual Demand .................................... 3-5 Figure 3.4 Existing Recycled Water Customers .......................................................... 3-7
Figure 3.5 Recycled Water Peaking Factors by Month .............................................. 3-11 Figure 3.6 Daytime Irrigation ...................................................................................... 3-12
Figure 3.7 3-Hour Evening Irrigation .......................................................................... 3-13
Figure 3.8 Other Irrigation Users ............................................................................... 3-13 Figure 3.9 Potential Recycled Water Customers ....................................................... 3-17
Figure 3.10 Potential Recycled Water Customers along Avenida Encinas ................. 3-19
Figure 3.11 Potential Recycled Water Customers near Palomar Airport ..................... 3-20 Figure 3.12 Distribution of Potential Demands by Service Area .................................. 3-35
Figure 3.13 Large User Demand Ranking Effect ......................................................... 3-36
Figure 3.14 Areas of Potential Development Incorporating Recycled Water ............... 3-39 Figure 3.15 Potential Build Out Demand Summary ..................................................... 3-41
Figure 4.1 Historical Supply ......................................................................................... 4-5
Figure 4.2 Historical Supply by Source ........................................................................ 4-5 Figure 4.3 Seasonal Storage Requirement ................................................................ 4-10
Figure 4.4 Existing and Potential Recycled Water Supplies ...................................... 4-13
Figure 4.5 Maximum Month Demand ......................................................................... 4-16 Figure 4.6 Process Flow Diagrams ............................................................................ 4-20
Figure 4.7 Supply Alternatives Comparison ............................................................... 4-30
Figure 4.8 Required Potable Supplement as Seasonal Supply ................................. 4-34 Figure 5.1 Groundwater Basin Map ........................................................................... 5-11
Figure 6.1 Screenshot of Hydraulic Model ................................................................... 6-3 Figure 6.2 Calibration Locations ................................................................................ 6-11
Figure 6.3 System Wide Diurnal Demand Patterns ................................................... 6-16
Figure 6.4 Reservoir Calibration Results ................................................................... 6-19 Figure 6.5 Water Quality Calibration Results ............................................................. 6-21
Figure 7.1 Operational Storage Requirement .............................................................. 7-4
Figure 8.1 Pressures Greater than 125 psi .................................................................. 8-3 Figure 8.2 Low Pressure and High Velocities .............................................................. 8-5
Figure 8.3 Existing System Water Quality ................................................................. 8-15
Figure 9.1 System Alternative Alignments ................................................................... 9-5 Figure 9.2 Alternative Alignment 4A ............................................................................ 9-8
Figure 9.3 Alternative Alignment 4B ............................................................................ 9-9
Figure 9.4 Alternative Alignment 4C .......................................................................... 9-10 Figure 9.5 Expansion Segment Unit Costs ................................................................ 9-17
Figure 9.6 Expansion Segment Unit Costs ................................................................ 9-20
Figure 9.7 Proposed Pressure Zones ........................................................................ 9-25 Figure 9.8 Phase III Supply Strategy ......................................................................... 9-27
Figure 9.9 Build Out Supply Strategy ......................................................................... 9-27
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Figure 9.10 Build Out Supply Strategy with Seasonal Storage .................................... 9-29 Figure 10.1 Capital Cost by Phase ............................................................................. 10-12
Figure 10.2 Phasing of Potential Expansion Segments ............................................. 10-13
Figure 10.3 Capital Cost by Project Type ................................................................... 10-15 Figure 10.4 Escalated Capital Cost ............................................................................ 10-16
Figure 10.5 Comparison of Unit Costs to Imported Water ......................................... 10-17
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LIST OF ABBREVIATIONS
Abbreviation Description
AACE Association for the Advancement of Cost Engineering
AAD Average Annual Demand
ACP Asbestos Cement Pipeline
ADD Average Day Demand
af Acre Feet
afy Acre Feet per Year
AL Action Level
AWWA American Water Works Association
BSD Buena Sanitation District
Carollo Carollo Engineers
CCB Chlorine Contact Basin
CCR California Code of Regulations
CCL3 Contaminant Candidate List 3 (third version)
CDPH California Department of Public Health
CEC Constituents of Emerging Concern
CIP Capital Improvement Program
City City of Carlsbad
CML&C Cement mortar lined and coated steel
CMWD Carlsbad Municipal Water District
COO City of Oceanside
CWC California Water Code
CWRF Carlsbad Water Recycling Facility
DDT Dichloro-Diphenyl-Trichloroethane
DEH Department of Environmental Health
DIP Ductile Iron Pipeline
District Carlsbad Municipal Water District
DPH Department of Public Health
DPS Department of Public Safety
DWR Department of Water Resources
EDC Endocrine Disrupting Compounds
ENR Engineering News Record
EOO Encina Ocean Outfall
EPA Environmental Protection Agency
EPS Extended Period Simulation
EWPCF Encina Water Pollution Control Facility
ET Evapotranspiration
EWA Encina Wastewater Authority
FCV Flow control valve
ft Feet
ft/kft Feet per thousand feet
ft-msl Feet above mean sea level
ft/s Feet per second
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Abbreviation Description
gal Gallon
GIS Geographic Information System
gpd/ac Gallons per day per acre
gpm Gallons per minute
GWRP Gafner Water Reclamation Plant
H2OMAP Water Hydraulic Modeling software package from MWH Soft, Inc.
HCF Hundred cubic feet
HDPE High density polyethylene
HGL Hydraulic Grade Line
HOA Home Owners Association
hp Horsepower
HPT Hydro-pneumatic Tank
HSA Hydrological Sub Area
HT Hydro-pneumatic Tank
HU Hydrological Unit
HWL High Water Line
I-5 Interstate 5
in Inches
kWh Kilowatt-hour
LRP Local Resources Program
LWWD Leucadia Wastewater District
MBR Membrane Bioreactor
MCL Maximum Contaminant Level
MDD Maximum Day Demand
MF Micro Filtration
MF Multiple Family
MG Million Gallon
mgd Million gallons per day
mg/L Milligrams per liter
MinDD Minimum Day Demand
MMD Maximum Month Demand
MOA Memorandum of Agreement
MPN Most Probably Number
msl Mean sea level
MWD Metropolitan Water District of Southern California
MWRF Meadowlark Water Reclamation Facility
NDMA N-nitrosodimethylamine
NTU Nephelometric Turbidity Unit
OOS Out of Service
O&M Operations and Maintenance
OMWD Olivenhain Municipal Water District
PCBs Polychlorinated Biphenyls
PHD Peak Hour Demand
PRS Pressure Regulating Station
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Abbreviation Description
PRV Pressure Reducing Valve
PSV Pressure Sustaining Valve
PS Pump Station
psi Pounds per square inch
PVC Polyvinyl chloride
RO Reverse Osmosis
RWMP Recycled Water Master Plan
RWQCB Regional Water Quality Control Board
SAR Sodium Adsorption Ratio
SCADA Supervisory Control and Data Acquisition
SDCWA San Diego County Water Authority
SDWA Safe Drinking Water Act
SF Single Family
SLRWRF San Luis Rey Wastewater Reclamation Facility
SMCL Secondary Maximum Contaminant Level
STL Steel
SWRCB State Water Resources Control Board
SWTF Stormwater Treatment Facility
TAP Tri-Agency Pipeline
TDH Total Dynamic Head
TDS Total Dissolved Solids
VID Vista Irrigation District
VWD Vallecitos Water District
VFD Variable Frequency Drive
WDF Water Demand Factor
WPCF Water Pollution Control Facility
WRF Water Reclamation Facility
WRP Water Reclamation Plant
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EXECUTIVE SUMMARY
ES.1 PROJECT BACKGROUND
Carlsbad Municipal Water District (CMWD) started its recycled water program in 1990 with
the preparation of its first Recycled Water Master Plan (RWMP). Subsequently, CMWD
issued a mandatory use ordinance and started implementing the recycled water system
facilities of Phase I. CMWD served over 1,000 acre-feet per year (afy) of recycled water by
1995. The implementation of Phase II started in 2000 and included construction of the
4-mgd Carlsbad Water Recycling Facility (CWRF) and expansion of the Meadowlark Water
Reclamation Facility (MWRF), improvements to Mahr Reservoir, three new booster pump
stations, and 24 miles of additional recycled water pipeline. Construction of Phase II was
completed in 2008 and the CMWD currently serves approximately 4,000 afy of recycled
water.
With Phase II near completion, CMWD initiated the development of this RWMP update to
evaluate the capabilities of the existing recycled water system, define the most cost-
effective system expansions through build out conditions, and develop a capital
improvement program (CIP). This CIP includes a recommended phasing strategy and
defines the Phase III projects. A separate Phase III Project Feasibility Study was also
prepared as part of this project but is documented in a separate report.
ES.2 STUDY AREA
The study area of this RWMP is the existing service area of CMWD as well as areas within
neighboring districts adjacent to CMWD’s service area. As shown in Figure ES.1, CMWD
currently provides potable water and recycled water within a portion of the City of Carlsbad
(City) located approximately 35 miles north of downtown San Diego. CMWD’s existing
recycled water system extends to all parts of the City except the northwest quadrant. This
RWMP evaluates opportunities to expand recycled water service throughout CMWD’s
service area as well as to a select number of large potential recycled water customers in
neighboring communities.
ES.3 EXISTING RECYCLED WATER SYSTEM
CMWD’s primary recycled water distribution system consists of five pressure zones, three
storage tanks, three booster pumping stations, two supply sources with pump stations, and
three pressure regulating stations. CMWD also supplies recycled water to the south course
of the La Costa Resort and Spa from the Gafner Water Reclamation Plant (WRP) through a
separate distribution system with dedicated service to the south golf course of the La Costa
Resort and Spa. The location of these facilities and supply sources are shown in Figure 2.1
of this RWMP.
ALGA RDCAR
LS
BAD
B
L
AVIA
R
A
P
Y
TAMAR
A
C
K
A
V
CARLS
B
A
D
VIL
L
A
G
E
D
R
EL CAMI
NO REALLEUCADIA BL
ENC IN ITAS BL
RANCHO SANTA FE RDSAN MARCOS BL
RANC
H
O S
A
N
T
A FE
R
D
PALOMAR AIR P O R T RD
C O LL E GE BLL A C OSTA AVPOINSETTIA LNEL CAMINO REALE
L CAMI
NO REAL
CAN N O N R DMELROSE D
R
OLIVENHAIN RD RA N CH O S A NTA FE RDCAMINO JUNIPERO
Agua HediondaLagoon
City ofOceanside
Carlsbad MunicipalWater District
Olivenhain MunicipalWater District
San DieguitoWater District
VallecitosWater District
Vista Irrigation District
Buena VistaLagoon
Batiquitos Lagoon
Pacific Ocean
Santa FeIrrigation District
Figure ES.1Study AreaRecycled Water Master PlanCarlsbad Municipal Water District
0 5,000 10,000
Feet
Legend
Water District Boundaries
Carlsbad Municipal Water District
City of Oceanside
Olivenhain MunicipalWater District
San Dieguito Water District
Vallecitos Water District
Vista Irrigation District
Santa Fe Irrigation District
Carlsbad City Limits
Other
Freeways
Major Roads
Local Streets
Water Body
Also Included in Study Area
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ES.4 RECYCLED WATER SUPPLIES
CMWD currently receives recycled water from the Carlsbad Water Recycling Facility
(WRF), owned by CMWD but operated by the Encina Wastewater Authority (EWA), the
Meadowlark WRF, owned and operated by the Vallecitos Water District (VWD), and the
Gafner WRP, owned and operated by the Leucadia Wastewater District (LWWD).
Table ES.1 summarizes the existing supply sources of recycled water for CMWD, while the
locations of each of these facilities are shown on Figure ES.3.
Table ES.1 Recycled Water Supplies
Recycled Water Master Plan Carlsbad Municipal Water District
Reclamation
Plant Name Owner
Permitted Capacity(1)
(mgd)
Maximum CMWD Allocation
(mgd)
Other Allocations
(mgd)
CWRF CMWD 4.0 4.00 0.0
MWRF VWD 5.0 3.00(1) 1.5(1)
GWRP LWWD 1.0 0.75(1) 0.0
Total Capacity 10.0 7.75 1.5
Total Usable Capacity(1) 7.60(1)
Notes:
VWD = Vallecitos Water District; LWWD = Leucadia Wastewater District; GWRP = Gafner WRP (1) Details and assumptions are included in Chapter 4.
To serve the projected recycled water demands, six (6) different supply alternatives were
developed. Each alternative has an assumed total build out supply capacity of 14-mgd,
which was used to develop comparable alternatives. The six alternatives are:
• Alternative 1 - Maximize use of Carlsbad WRF
• Alternative 2 - Maximize use of Meadowlark WRF
• Alternative 3 - Maximize use of Gafner WRP
• Alternative 4 - Abandon Gafner WRP
• Alternative 5 - Maximize use of Carlsbad WRF and Lake Calavera
• Alternative 6 - Utilize Shadowridge WRP
The breakdown of the distribution of supplies to add up to 14 mgd for each of the six
alternatives is summarized in Table ES.2.
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Table ES.2 Supply Alternatives Summary
Recycled Water Master Plan Carlsbad Municipal Water District
Supply Source Facility
Treatment Flow(1) (mgd) Alternative 1 Maximize CWRF Alternative 2 Maximize MWRF Alternative 3 Maximize GWRP Alternative 4 Abandon GWRP Alternative 5 Maximize CWRF and Lake Calavera Alternative 6 Utilize Shadowridge WRP Carlsbad WRF 10.25 9.75 7.00 11.00 9.00 9.75
Meadowlark WRF 3.00 3.50 3.00 3.00 3.00 3.00
Gafner WRP 0.75 0.75 4.00 - 0.75 0.75
Calavera Reservoir SWTF - - - - 1.00 -
Seasonal Storage - - - - 0.25 0.20
Shadowridge WRP - - - - - 0.30
Total 14.00 14.00 14.00 14.00 14.00 14.00
Notes:
WRF = Water Reclamation Facility; WRP = Water Reclamation Plant; SWTF = Stormwater Treatment Facility (1) Details and assumptions are included in Chapter 4.
A summary of the estimated capital cost and unit supply cost in $/acre-foot (af) are listed in
Table 4.11 and graphically presented on Figure ES.2.
$191
$300
$1,305
$181
$335 $404
$0
$200
$400
$600
$800
$1,000
$1,200
$1,400
$1,600
0
2
4
6
8
10
12
14
16
Alt. 1 Alt. 2 Alt. 3 Alt. 4 Alt. 5 Alt. 6 Unit Supply Cost ($/af)Supply Capacity (mgd)CWRF GWRP MWRF
SWTP Seasonal Storage SWRP
Unit Cost ($/af)
Figure ES.2 Supply Alternatives Comparison
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As shown on Figure ES.2, the majority of the recycled water supply capacity is produced at
the Carlsbad WRF in all alternatives, ranging from 7 to 11 mgd of the total 14-mgd supply
capacity. This figure clearly shows that the variations between alternatives are determined
by the supply mix of the remaining 3 to 7 mgd of the total 14 mgd capacity.
The narrow variation in supply mix between the five of the six alternatives is caused by the
limited supply availability and/or expansion opportunities for the GWRP, MWRF, SWTP,
and SWRP. The Carlsbad WRF is the only treatment plant with extensive expansion
opportunities and already has a secondary treatment capacity of 43.3 mgd.
In addition to the supply mix of each alternative, Figure ES.2 also shows that the estimated
unit capital supply cost in dollars per acre-foot range from $181/af to $1,305/af.
Alternative 4 is the most cost-effective scenario, while Alternative 1 the second best
alternative.
More details on each supply source and the supply evaluation is provided in Chapter 4 of
this RWMP.
ES.5 RECYCLED WATER DEMANDS
ES.5.1 Existing Demands
CMWD’s recycled water demand has steadily increased from zero afy at the start of
Phase I in 1990 to 4,350 afy in calendar year 2009. As of December 2010, CMWD serves
362 customers. CMWD’s top five largest customers comprise over one-third of the total
demand for 2009. In addition, Home Owners Association (HOA) irrigation and commercial
property irrigation, such as shopping centers and business parks, comprise a significant
portion of the system’s total demand. For planning purposes, the existing distribution
system is estimated to serve approximately 4,000 afy.
ES.5.2 Near-Term Demands
CMWD is already in the process of connecting nearly 50 new (near-term) customers with a
combined demand of 100 afy. This demand is therefore referred to as the so-called “near-
term” demand.
ES.5.3 Future Demand Projections
The future recycled water demands were projected using a variety of sources, including
potable water billing records, land use maps, aerial photography, previous reports, studies
from neighboring agencies, and discussions with CMWD staff. A list of 161 potential new
recycled water customers was developed and input into a GIS database. The total
additional potential future demand based on the customer database is nearly 5,368 afy.
This demand includes all potential users including future developments, but does not
include several potential agricultural users since they are temporarily occupying land
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planned for future home owners associations and commercial developments. The
customers were separated into four main categories and thirteen subcategories, which are
described in more detail in Chapter 3. A detailed list of all potential customers is included in
Appendix B.
In addition to the customer database, demand estimates were prepared for agricultural
areas that can be temporarily served with recycled water and vacant areas for which no
specific plans are available at this time.
The total demand for the ultimate system is projected by combining the demands from
existing and near-term customers, the potential customer database, and the arnew
developments. Table ES.3 presents a summary of demand projections. This table also lists
the corresponding table in Chapter 3 that provides more detail on each demand estimate.
Table ES.3 Summary of Demand Projections Recycled Water Master Plan Carlsbad Municipal Water District
Customer Category Demand (afy) Source
Existing 4,000 Section 3.3.2
Near Term / In Progress 100 Section 3.5.3
Customer Database 5,368 Table 3.7
New Developments 344 Table 3.9
Potential Total Demand 9,812
Not Feasible -706 Table 3.13
Total for Build-out System 9,106
As shown, the total potential recycled water demand is estimated at 9,812 afy. It should be
noted that this is not the build out demand included in the CIP, as the location of certain
potential customers would require cost-prohibitive infrastructure expansions.
The feasibility analysis of the various pipeline alignments required to serve this total
potential demand is described in Chapter 9, Future System Analysis. The results of this
analysis were used to prioritize pipeline extension projects and determine the build out
demand that is considered for the CIP projects presented in Chapter 10 of this RWMP. As
shown in Table ES.3, a total of 706 afy in potential demand is considered not feasible,
resulting in a build out demand of 9,106 afy. This equates to an average day demand
(ADD) of 8.1 mgd and a maximum day demand (MDD) of 13.5 mgd.
The list of potential customers includes customers outside CMWD’s service area. As
presented in Chapter 3, nearly 50 percent of the potential customers identified within this
plan are located inside CMWD’s service area. Implementation of the system expansions
described in this RWMP would therefore require collaboration with neighboring agencies
January 2012 7 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Executive Summary
and not only offset potable water demands within CMWD’s service area, but also diversify
supplies in neighboring agencies.
Currently, recycled water use accounts for almost 20 percent of the aggregate water within
CMWD. If all potential demands within CMWD are connected by year 2020, CMWD could
reach 27 percent recycled water when compared to total demand.
ES.6 HYDRAULIC MODEL
A hydraulic model was developed and calibrated for this project to evaluate the existing
system and determine the future system expansions projects for the CIP. A detailed
description of the model creation and calibration is included in Chapter 6 of this RWMP.
ES.7 EXISTING SYSTEM EVALUATION
The hydraulic model was used to evaluate the system hydraulics of the existing recycled
water distribution system. The evaluation and planning criteria used for this evaluation are
described in Chapter 7 of this RWMP. In summary, the following conclusions were made:
• All booster pump stations are adequately sized.
• The system has sufficient reservoir storage.
• The system has sufficient recycled water supplies to meet MMD.
• There are some hydraulic deficiencies in the distribution system such as areas with
high velocity, high head loss, high pressure, or low pressure.
• There are a few locations with low chlorine residual levels.
After an evaluation of the severity of the deficiencies, replacement of the existing system
was not recommended. To resolve the water quality deficiencies, the following
recommendation was made and included in the CIP, which is presented in Chapter 10 of
this RWMP:
• Installation of a chlorination and mixing system in “C” Tank to maintain an adequate
residual during periods of low demand.
ES.8 FUTURE SYSTEM EVALUATION
The hydraulic model was expanded by connecting potential customers identified in the
future customer database. Pipeline alignments were selected with input from CMWD staff in
an attempt to connect all potential customers. The model with this build out distribution
system was then used to size pipelines, define pressure zone boundaries, locate new
booster pumping stations and reservoirs.
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The pipeline alignments of this build out system were then divided into 18 different
expansion segments. The alignments of the segments are shown on Figure ES.3, while a
summary of the potential customer demands by segment is provided in Table 9.1.
To determine the most cost-effective system expansion, the various segments were
evaluated based on the estimated conveyance cost in dollars per acre-foot of demand
served ($/af). The segments were then prioritized based on unit conveyance cost and
incorporated in the CIP. The resulting ranking is presented in Figure ES.4.
Table ES.4 Summary of Ultimate Demands by Phase
Recycled Water Master Plan Carlsbad Municipal Water District
Phase
Ultimate System
Demand (afy)
Average Day
Demand (mgd)
Maximum Month
Demand(2) (mgd)
Existing + Near Term 4,100 3.7 6.3
Phase III Expansion Segments(1) 3,314 2.9 4.7
Phase III Subtotal 3,314 2.9 4.7
Phase III Total 7,414 6.6 11.0
Build Out Expansion Segments 1,348 1.2 2.0
Development of Vacant Land 344 0.3 0.5
Build-Out Phase Subtotal 1,692 1.5 2.5
Ultimate System Total 9,106 8.1 13.5
Notes:
(1) Assumes that all potential customers adjacent to the existing system are connected during Phase III (2) MMD peaking factors vary by customer (see Appendix C for details).
As shown in Table ES.4, a total of 9,106 afy of demand was identified as the ultimate
system demand. It is estimated that the total Phase III demand would be approximately
7,414 afy.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" TanksCamino Re
al
Marron Rd
Ca
rl
s
ba
d
Bl
vd
A lo n d r a W a y
Paseo NorteC ollege B lvd
Palomar Airport RD
Aviara Pkwy El Fuerte StCosta Ave
P o in s e ttia L n
T a m a r a c k A v e
Cannon Rd
Calle BarcelonaRanch o Santa FeCalavera PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
LakeCalavera
Corintia Meter
OMWDMeter
8"
Carlsbad villageRedundancy
Pipeline
8"8"San Marcos
Vista
Encinitas
Oceanside
4
2
35
1
6
12
89
10
11
7
13
14 18
15 16 1714"8"12"6"4"
16"
4"
1
2
"
6 "4"8"
6
"
12"4"4 "
4"6"6"
12"
8"6"6"
4
"6"4"
8"
6"
8"6"
6 "
4"8"
8
"
6
"
4"
6"6"6
"
8"8"6"4"
8 "
6"12"6"8"8"8"4 "
8"8"6"
6 "8"8"6"6"4"6"
6"
6 "6"8"6"4"6"8"4"4 "8"12"4"
12"12"6 "
8"6"6
"6"4"
8"
8"
6"
6 "6"8"12"8"C017
C032
C177
C176C175
C173
C179
C170
C169
C166
C178
C165
C164
C163
C161
C064
C158
C126
C119
C116
C157
C156
C155
C153
C152 C151
C150
C149
C148
C147
C146
C145C144
C143 C102
C123
C103
C112
C101
C105
C111
C114
C136C125
C129
C134
C139C121
C117
C124
C115
C113
C128
C108C130
C127
C118
C122
C131C120
C133
C107
C109
C141
C137
C135
C104
C100
C094
C005 C009
C001
C008
C074
C071
C087
C010
C088
C042
C044
C041
C068
C051
C063
C037
C043
C078
C040
C047
C045
C003
C013
C020
C027
C004
C021
C028
Legend
Existing Pipelines
Less than 6"
6" to 8"
10" to 14"
16" and larger
Customer (by demand in afy)
<10
10-25
25-50
50-100
>100
Recycled Water Facilities
Pump Station
PRS
Meter
WRF
Tank
Reservoir
Inactive WRP
Other
Freeways
Railroads
Local Streets
Protential Golf Courses
Water Body
Carlsbad City Limits
San Diego County
Carlsbad Municipal Water District Boundary
0 5,000 10,000Feet
Figure ES.3Potential Expansion Segments
Recycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_ES_3-Expansions Segment by Color.mxdDATE: 1/18/2011Segment 1
Segment 2
Segment 3
Segment 4
Segment 5
Segment 6
Segment 7
Segment 8
Segment 9
Segment 10
Segment 11
Segment 12
Segment 13
Segment 14
Segment 15
Segment 16
Segment 17
Segment 18
New Developments
Other (Not for Specific
Potential Expansion Segments
Expansion Segment)
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0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
$0
$500
$1,000
$1,500
$2,000
$2,500
$3,000
$3,500
$4,000
$4,500
$5,000
4A 8 3 7 10 2 9 4B 14 15 4C 16 1 5 18 13 6 12 17 11 Cumulative Demand (afy)Conveyance Unit Cost ($/acre-ft)Phase III Expansion Segments Build-out Expansion Segments Cumulative Potential Demand (afy)
Note: Conveyance costs donot include treatment costs.
expansions near to existing projects
Figure ES.4 Expansion Segment Unit Costs
As shown in Figure ES.4, the estimated conveyance unit costs for the segments range
significantly, from less than $100/acre-foot to over $2,500/acre-foot. This figure also shows
the cumulative demand of all expansion segments as 4,662 afy. It should be noted that this
does not include the existing system demand, near-term demand, or the demand of
customers located adjacent to the existing system that do not require new pipeline
segments. A summary of the total ultimate demand by phase is shown in Table ES.4.
This figure also shows that the incremental new demand decreases significantly after
implementation of expansion segment 15, while the unit cost for conveyance continues to
increase. As this is close to the point where the unit conveyance costs exceed $1,500/acre-
foot, it was decided to define all segments up to Expansion Segment 4C as Phase III and
categorize the remaining segments for the build out, as discussed in Chapter 9.
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ES.9 CAPITAL IMPROVEMENT PROGRAM
The CIP is divided into three phases. The existing phase includes recommendations made
as a part of the existing system analysis. The second phase consists of the projects to be
implemented as a part of the Phase III improvement program, while the third phase consists
of the remaining projects anticipated through build-out of the recycled water system. The
locations of the projects included in Phase III and the Build-out Phase are shown on
Figure ES.5.
The breakdown of cost by phase is summarized in Table ES.5.
Table ES.5 Capital Cost by Planning Phase
Recycled Water Master Plan Carlsbad Municipal Water District
Project Type Existing Phase III Build-out Phase Total
Pipelines $0.0 $20.7 $40.1 $60.7
Treatment $0.0 $7.0 $5.5 $12.5
Storage $0.1 $4.6 $5.7 $10.4
Total $0.1 $32.3 $51.3 $83.7
Note: (1) Capital Costs are based on the cost assumptions discussed in Chapter 10. Detailed information for each project can be found in Table 10.4.
As shown in Table ES.5, the total capital cost for existing system improvements is about
$0.6 million, while the capital cost of Phase III is estimated at $32.3 million. The expansions
required to connect all customers of the Build-out Phase will add approximately
$51.3 million in capital cost, for a total capital cost of $83.7 million.
This table also shows that pipelines represent the largest component of the total capital
cost at about $60.7 million. Treatment and storage are similar in cost, at $12.5 million and
$10.4 million, respectively. Figure ES.6 presents the capital cost by project type graphically.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" TanksCamino Re
al
E lm A v e
Marron Rd
Ca
rl
s
b
a
d
Blv
d
H
i
g
h
la
n
d Dr
A lo n d ra W a y
Paseo NorteF a ils a f e P ip e lin e
Palomar Airport RD
Aviara Pkwy El Fuerte StCosta Ave
P o in s e ttia L n
T a m a ra c k A v e
Cannon Rd
Calle BarcelonaRanch o Santa FeCalavera PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon
Oceanside
Shadowridge WRP
LakeCalavera
Corintia Meter
OMWDMeter
8"
4A
4B
4C San Marcos
Vista
Encinitas
Oceanside
4
2
35
1
6
7
89
10
11
18
171615
13
11
12
14
C017
C032
C177
C176
C175
C174
C173
C179
C170
C169
C168
C178
C165
C164 C163
C162
C161
C064
C159
C158
C126
C119C116
C157
C156
C155
C153
C152 C151
C149
C148
C147
C146
C145C144
C143 C102
C123
C103
C112
C101
C105
C111
C114
C136C125
C129
C134
C139C121
C124
C115
C113
C128
C108C130
C127
C118
C122
C131C120
C133
C107
C109C140
C141
C137
C132
C135
C104
C093
C099
C100
C005 C009
C001
C061
C074
C071
C062
C087
C010
C088
C042
C056
C044
C041 C034
C051
C063
C037
C043
C078
C018
C070
C045
C003
C013
C020
C027
C004
C021
C028
Legend
Existing Pipelines (by Diameter)
Less than 6"
6" to 8"
10" to 14"
16" and larger
Potential Expansion Segments
Phase III
Build Out
New Development Areas
Already Constructed
Recycled Water Facilities
Pump Station
Pressure Regulating Station (PRS)
Meter
WRF
Tank
Reservoir
Inactive WRP
Other
Freeways
Railroads
Major Roads
Local Streets
Water Body
Carlsbad City Limits
San Diego County
Carsbad Municipal Water District Boundary
0 5,000 10,000
Feet
Figure ES.5CIP Phasing
Recycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_ES_5-CIP Phasing.mxdDATE: 1/18/2011
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Pipelines $60.7M 73%
Treatment $12.5M 15%
Storage $10.4M 12%
Total Build-out CIP$83.7 million
Figure ES.6 Capital Cost by Project Type
It is anticipated that completion of Phase III will require approximately 10 years (2011-
2020), five years for building the Phase III infrastructure and five years to connect the
customers. It is assumed that the Build-out Phase is will take another ten years and be
completed by 2030. Based on this timing, the escalated capital project costs were
estimated as shown in Table ES.6.
Table ES.6 Escalated CIP by Planning Phase
Recycled Water Master Plan
Carlsbad Municipal Water District
Phase Period
Capital Cost
($million)
Escalated Capital Cost
($million)
Existing 2010 $0.1 $0.2
Phase III 2011-2020 $32.3 $35.3
Build-out
Phase 2021-2030 $51.3 $75.4
Total n/a $83.7 $110.9
Figure ES.7 depicts the estimated escalated unit recycled water cost compared to the
anticipated potable water unit cost from the San Diego County Water Authority, which
provides the alternate water supply to CMWD.
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$0
$500
$1,000
$1,500
$2,000
$2,500
2010 2015 2020 2025 2030Unit Cost ($/af)Year
Treatment and Storage Conveyance
Treated Imported Water Cost (SDCWA)Projection
Recycled Water System Expansion
Phase III
Build Out
Note: Costs exclude Operation and Maintainance
Figure ES.7 Comparison of Unit Costs to Imported Water
As shown in Figure ES.7, the anticipated unit cost of recycled water for each phase is
below the projected imported water costs for the same time period. Based on this
comparison it is concluded that the expansion of CMWD’s recycled water system in both
Phase III and through Build Out conditions is a cost-effective alternative for potable water
supply. In addition to the cost benefit, recycled water provides increased supply reliability,
especially during drought periods, and allows CMWD remains more in control of the overall
water supply cost for its customers.
January 2012 1-1 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 1
Chapter 1
INTRODUCTION
1.1 INTRODUCTION
Many Southern California communities must contend with a multitude of challenges when
providing a reliable water supply. The drought occurring through 2010, legal and
environmental constraints, climate change, and population growth all have the aggregate
effect of reducing the reliability of most water supplies. As recycled water provides a
reliable, drought-resistant supply, the Carlsbad Municipal Water District (CMWD) has been
providing recycled water to the City of Carlsbad (City) since 1991. To continue this
program, CMWD has undertaken this Recycled Water Master Plan (RWMP) update to
guide the continued development of its recycled water system.
This chapter includes descriptions of the project background, study area, and project
objectives. In addition, acknowledgments and an overview of the report organization are
included. A list of reference documents used for the preparation of this RWMP is included in
Appendix A, while a list of abbreviations and acronyms is included after the Table of
Contents.
1.2 PROJECT BACKGROUND
The CMWD started its recycled water program in 1990 with the preparation of its first
Recycled Water Master Plan. Subsequently, CMWD issued a mandatory use ordinance and
started implementing the recycled water system facilities of Phase I. With recycled water
purchased from neighboring agencies, Vallecitos Water District (VWD) and Leucadia
Wastewater District (LWWD), CMWD served over 1,000 acre-feet per year (afy), or
0.89 million gallons per day (mgd), of recycled water by 1995. With Phase I complete,
CMWD hired Carollo Engineers in 1997 to update its recycled water master plan and
prepare a plan for the Phase II expansion. Phase II included construction of the 4 mgd
(4,480 afy) Carlsbad Water Recycling Facility (CWRF), increased supply from the
Meadowlark Water Reclamation Facility (MWRF) from 2.25 mgd (2,520 afy) to 5 mgd
(5,600 afy), reliability and control improvements to Mahr Reservoir, three new booster pump
stations, and 24 miles of additional recycled water pipeline.
Construction of Phase II was initiated in 2004, and went into full operation in January 2008.
Currently, CMWD is still connecting Phase II customers to the distribution system and the
Phase II system demand is anticipated to increase to approximately 5,000 afy (4.5 mgd)
once all Phase II customers are connected. With Phase II near completion, CMWD is ready
to take the next steps for further recycled water system expansion. With most of the large
water customers already converted to recycled water, the next challenge is finding cost
effective expansions that effectively continue the development of CMWD’s recycled water
system. The purpose of this Recycled Water Master Plan (RWMP) Update is to document
1-2 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 1
the capabilities of the existing system and evaluate potential system expansions. The goal
of this document is to determine preferred system expansions and develop a capital
improvement program (CIP) with a phased implementation approach to reach build out
conditions. In addition, a separate Phase III Project Feasibility Study was prepared as part
of this project that provides details on the implementation of Phase III.
1.3 STUDY AREA
The project study area is the service area of CMWD as well as some of the surrounding
areas of neighboring agencies. CMWD provides potable water and recycled water within a
portion of the City of Carlsbad (City) located approximately 35 miles north of downtown San
Diego. As shown in Figure 1.1, CMWD’s service area covers most of the City’s boundary,
with special service districts providing service for the southeast corner of the City. It should
be noted that, through an agreement dated September 24, 2008 (included in Appendix D),
CMWD retails recycled water within VWD outside CMWD’s service area but within the City
of Carlsbad.
CMWD is a subsidiary district of the City of Carlsbad. The mayor and City Council are
CMWD’s governing board. CMWD management and engineering operates under the City’s
Utilities Department. CMWD is governed by the Municipal Water District Act of 1911.
The City is a member of the Encina Wastewater Authority (EWA) along with the City of
Vista, the City of Encinitas, the Buena Sanitation District, LWWD, and VWD. Wastewater
treatment is handled on a regional basis by EWA. The study area includes both wastewater
supply sources outside of the CMWD boundary and potential customers outside the CMWD
boundary who could purchase recycled water. CMWD’s boundary in relation to these
wastewater agencies is shown in Figure 1.2.
Currently, CMWD’s existing recycled water system extends to all parts of CMWD except the
upper portion of the northwest quadrant. This RWMP evaluates opportunities to expand
recycled water service throughout CMWD’s service area as well as to a select number of
large potential recycled water customers in neighboring communities.
ALGA RDCAR
LS
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ENC IN ITAS BL
RANCHO SANTA FE RDSAN MARCOS BL
RANC
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C O LL E GE BLL A C OSTA AVPOINSETTIA LNEL CAMINO REALE
L CAMI
NO REAL
CAN N O N R DMELROSE D
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OLIVENHAIN RD RA N CH O S A NTA FE RDCAMINO JUNIPERO
Agua HediondaLagoon
City ofOceanside
Carlsbad MunicipalWater District
Olivenhain MunicipalWater District
San DieguitoWater District
VallecitosWater District
Vista Irrigation District
Buena VistaLagoon
Batiquitos Lagoon
Pacific Ocean
Santa FeIrrigation District
Figure 1.1City and Water DistrictBoundariesRecycled Water Master PlanCarlsbad Municipal Water District
0 5,000 10,000
Feet
Legend
Water District Boundaries
Carlsbad Municipal Water District
City of Oceanside
Olivenhain MunicipalWater District
San Dieguito Water District
Vallecitos Water District
Vista Irrigation District
Santa Fe Irrigation District
Carlsbad City Limits
Other
Freeways
Major Roads
Local Streets
Water Body
Also Included in Study Area
A L GA RDCARL
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T A M A R A C K A VCARLSBAD V ILL A G E D R
EL CAMI
NO REALLEUCADIA BL
ENC IN ITAS BL
RANCHO SANTA FE RDSAN MARCOS BL
R A N C H O SA N T A F E R D
PALOMAR AIRP OR T RD
C O LL E GE BLL A C OSTA AVPOINSETTIA LNEL CAMINO REALEL CAMI
NO REA
L
CAN NO N R DMELR
OS
E D
R
OLIVENHAIN RD RA N CHO S ANTA FE RDCAMIN
O JUNIPERO
Agua HediondaLagoon
City ofOceanside
City of Carlsbad
Leucadia
Wastewater District
Buena SanitationDistrict
Buena VistaLagoon
Batiquitos Lagoon
Pacific Ocean
Vallecitos Water District
City of Encinitas
City of Vista
Figure 1.2Sewer Districts
Recycled Water Master PlanCarlsbad Municipal Water District
0 5,000 10,000Feet
Legend
Sanitation District and Sewer
Service Boundaries
City of Carlsbad
City of Oceanside
Vallecitos Water District
Buena Sanitation Maintenance District
Leucadia Wastewater District
Other
Freeways
Major Street
Local Streets
Water Body
January 2012 1-5 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 1
1.4 PROJECT OBJECTIVES
The intent of this project is to provide a RWMP that will guide CMWD as it develops and
expands the current recycled water distribution system to build out. CMWD wants to
maximize the use of recycled water as this is now the lowest cost water supply source.
Specific project objectives are as follows:
• Maximizing recycled water use in and around CMWD.
• Finding cost effective system expansion opportunities.
• Optimizing the existing and future system configuration.
The plan culminates in a CIP that is intended to serve as guidance for CMWD to meet the
desired objectives. The CIP identifies several recycled water projects for CMWD, outlines
the recommended phasing of these projects, and includes planning level opinions of
probable construction cost.
1.5 ACKNOWLEDGEMENTS
Carollo wishes to acknowledge and thank all of the City’s staff for their support and
assistance in completing this master plan. Special thanks go to Bill Plummer, David Ahles,
and Elzbieta Karczewski.
Deputy City Engineer: Bill Plummer, P.E.
Senior Engineer: David Ahles, P.E.
Engineering Technician: Elzbieta Karczewski
Public Works Superintendent: Steve Plyler
Public Works Supervisor: Jase Warner
Senior Cross Connection Technician: Pam James-Adams
The following Carollo staff were principally involved in the preparation of this RWMP:
Partner-in-Charge: Gil Crozes, Ph.D., P.E.
Project Manager: Inge Wiersema, P.E.
Project Engineer: Brian Brenhaug, P.E.
Technical Review: Dan Baker, P.E.
Project Support Staff: Tracy Clinton, P.E.
Mark Bartlett, P.E.
Dawn Guendert
Li-Chen Wang
1-6 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 1
Carollo teamed with CH2M HILL for this RWMP update. Key staff members from CH2M
HILL involved in this project were:
Project Manager: Scott Lynch, P.E.
Anne Lynch, P.E.
Project Engineer: Jessica Prince, P.E.
Xiaoyi Zhang
1.6 REPORT ORGANIZATION
This recycled water master plan is divided into 10 chapters. A brief description of the
content of each chapter is provided below.
• Chapter 1 – Introduction: This chapter includes descriptions of the project
background, study area, and project objectives. In addition, acknowledgments and an
overview of the report organization are included.
• Chapter 2 – Existing Recycled Water System: This chapter provides a brief
overview of CMWD’s existing recycled water system including descriptions of the
existing recycled water distribution system/facilities, recycled water supply sources,
recycled water demands as well as known system deficiencies.
• Chapter 3 – Recycled Water Demands: This chapter presents a discussion of
CMWD’s estimated recycled water demands, including analysis of historical recycled
water demands, recycled water demand factors and peaking factors. This chapter
also summarizes the findings of the recycled water market assessment, a list of
identified potential customers, and the projected recycled water demands for
Phase III and build out conditions.
• Chapter 4 – Recycled Water Supplies: This chapter identifies the supply and
related storage needs required to meet the projected water demands identified in
Chapter 3, including descriptions of the existing and future recycled water supply
sources, a discussion of water quality of existing supply sources, a comparison of the
capacity of the identified sources with the projected recycled water demands to
determine any supply shortfalls, a supply evaluation consisting of four supply
scenarios, and a discussion of recommended supply strategy.
• Chapter 5 – Recycled Water Regulations. This chapter identifies the regulations
that govern the implementation and use of recycled water by CMWD, including
current and anticipated recycled water regulations as well as recommendations for
changes to CMWD’s design standards.
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• Chapter 6 – Hydraulic Model: This chapter discusses development and calibration
of the hydraulic model of CMWD’s existing recycled water system including
descriptions of CMWD’s previous hydraulic model, the various data sources used to
create the model, the modeling of facilities and their controls, the allocation of
demands, and the details of the calibration process. This chapter also documents
development of the future system model.
• Chapter 7 – Planning and Evaluation Criteria: This chapter summarizes the
analysis criteria used in the existing and future system analysis, as well as planning
criteria used in development of the capital improvement program.
• Chapter 8 – Existing System Evaluation: This chapter covers the analysis
performed on the existing system and summarizes results of that analysis, including
existing system deficiencies and recommendations for improvements to optimize the
existing system. This chapter also includes a discussion of inspection and
maintenance requirements and costs.
• Chapter 9 – Future System Evaluation: This chapter documents analysis of the
future system and summarizes results of that analysis. This chapter will include an
evaluation of the different routing alternatives and laterals to serve the potential
customers identified in Chapter 3 from the various supply alternatives discussed in
Chapter 4.
• Chapter 10 – Capital Improvement Program: This chapter provides planning level
cost estimates for the improvements recommended in Chapters 8 and 9. This CIP
includes a phased implementation schedule with a planning horizon of 2030 and a
separate project list for Phase III. A detailed implementation plan for Phase III is
presented in a separate report, the Phase III Feasibility Study.
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Chapter 2
EXISTING RECYCLED WATER SYSTEM
2.1 INTRODUCTION
This chapter provides a brief overview of Carlsbad Municipal Water District’s (CMWD)
existing recycled water system including descriptions of the existing recycled water
distribution system/facilities, recycled water supply sources, and recycled water demands.
A more detailed description of the recycled water distribution system pipelines and facilities
is included in Chapter 6 (Hydraulic Model Development), while detailed descriptions of the
existing and future recycled water demands and supplies are included in Chapter 3
(Recycled Water Demands) and Chapter 4 (Recycled Water Supplies), respectively.
2.2 SERVICE AREA
CMWD’s existing recycled water system is shown on Figure 2.1. As shown, CMWD
currently provides recycled water to customers inside and outside CMWD’s service area,
but are nearly within the City of Carlsbad (City).
Most of CMWD’s recycled water distribution system is within CMWD’s service area.
However, two portions of the recycled water distribution system are located outside
CMWD’s service area. A 12-inch transmission main in Pressure Zone 660 is located within
the Vista Irrigation District (VID) to the East of CMWD’s service area along Melrose and
Faraday Avenue.
A 30-inch transmission main outside CMWD’s service area is also located where CMWD’s
recycled water distribution system is fed from Meadowlark Water Reclamation Facility
(MWRF) within the service area of Vallecitos Water District (VWD). This pipeline ends along
Rancho Santa Fe Road, located to the southeast of CMWD’s service area. CMWD also
serves recycled water customers in the VWD within the City per the Mahr Reservoir Use
Agreement found in Appendix D.
2.3 EXISTING RECYCLED WATER SUPPLIES
CMWD receives recycled water from reclamation plants within the Encina Wastewater
Authority (EWA) service area. EWA is a public agency owned by the City of Carlsbad, City
of Vista, City of Encinitas, VWD, Buena Sanitation District (BSD), and Leucadia Wastewater
District (LWWD). EWA is operated through a Joint Powers Agreement date April 21, 2005
(see Appendix D). Under the Joint Powers Agreement, these six agencies share the costs
and management of wastewater treatment services through a joint outfall system. EWA
manages the 36-mgd Encina Water Pollution Control Facility (EWPCF) and the Encina
Ocean Outfall (EOO) at the terminus of this joint system. Member agencies are responsible
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for their individual wastewater collection systems that feed the trunk mains terminating at
the EWPCF.
CMWD receives recycled water from Meadowlark WRF, owned and operated by the
Vallecitos Water District, the Carlsbad Water Recycling Facility (CWRF), owned by CMWD
but operated by the EWA, and the Gafner Water Reclamation Plant (GWRP), owned and
operated by the LWWD. The ownership and capacity allocations from these three sources
are summarized in Table 2.1.
Table 2.1 Recycled Water Supplies Recycled Water Master Plan
Carlsbad Municipal Water District
Reclamation Plant
Name Owner(1)
CMWD Allocation Total Supply Capacity
(mgd) (afy) (mgd) (afy)
CWRF City 4 4,480 4 4,480
MWRF(2) VWD 3 3,360 5 5,600
GWRP(3) LWWD 0.75 840 0.75 840
Total (Peak) 7.75 8,680 9.75 10,920
Notes:
(1) VWD: Vallecitos Water District; LWWD: Leucadia Wastewater District; VID: Vista Irrigation District.
(2) CMWD’s allocation is 3.0 mgd in the summer and 2.0 mgd in the winter. Allocation for the Olivenhain Municipal Water District is between 1.0 mgd and 1.5 mgd depending on available flow. Based on the
design capacity of 5.0 mgd, there is spare capacity of 0.5 mgd. However, due to insufficient wastewater flows, the actual available flow of the plant is currently limited to about 3.4 mgd. Some of the spare capacity is required for transportation of solids.
(3) CMWD’s allocation for the La Costa Resort and Spa Golf Course is 0.75 mgd; however, peak historic usage is typically around 0.4 mgd. This supply is not connected to CMWD’s main recycled water system.
It should be noted that GWRP only serves the south course of La Costa Resort and Spa
and is not connected to the rest of CMWD’s recycled water distribution system. The
Meadowlark WRF operates as a “skimming” plant and extracts raw wastewater upstream in
the joint system while the Carlsbad WRF and Gafner WRP treat secondary effluent from the
EWPCF.
More details on CMWD’s recycled water supplies are provided in Chapter 4 of this RWMP.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" Tanks
Calavera PS
Bressi
PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
Faraday PRS
Avenida Encinas PRS
La Costa PRS
Kemper SportsManagement
Corintia Meter
OMWDMeter
LakeCalavera
EL CAMINO REAL
Maerkle Reservoir
La Costa Resort(North Course)
La Costa Ridge Pipeline
and Pump Station(Private)
Vista Irrigation District
Vallecitos Water District
Park HyattAviara Resort
La Costa Resort(South Course)
Legoland
Aviara ResortAssociationCANNON RD
P
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ALG A R D
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LA COSTA AV
RANCHO SANTA FE R D
OLIVENHAIN RD
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Legend
Water System Facilities
Largest Customers
Pump Station
Meter
Pressure Regulating Station (PRS)
Water Reclamation Facility (WRF)
Tank
Reservoir
Inactive WRP
Pipelines by Pressure Zone
318
384
550
580
660
Other
Private Pipeline
Freeways
Local Streets
Water Body
Carlsbad City Limits
San Diego County
Carlsbad Municipal Water District Boundary
0 5,000 10,000
Feet
Figure 2.1Existing Recycled Water System
Recycled Water Master PlanCarlsbad Municipal Water District
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_2_1 Existing System Ver B.mxdDATE: 5/10/2011
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2.4 EXISTING RECYCLED WATER CUSTOMERS
Recycled water delivery records were compiled and the average annual demands for the
past seven years are summarized by use type in Table 2.2.
Table 2.2 Existing and Historical Recycled Water Demands Recycled Water Master Plan Carlsbad Municipal Water District
Usage Type
Average Annual Demand(1) (afy)
2004 2005 2006 2007 2008 2009 2010
Agricultural Irrigation
(Flower Fields)
0 0 0 0 0 0 23
Commercial or
Industrial Process Water
0 0 0 0 0 0 0
Landscape Irrigation
Commercial
Property Irrigation (includes Apartments)
382 427 410 561 827 1,074 637
Community (Churches, etc.)
8 9 11 13 17 27 49
Golf Courses 596 703 713 780 1,036 1,133 1,033
Highways 52 52 31 46 28 25 11
HOAs 388 468 645 1,087 1,361 1,466 1,369
Resort Property Irrigation
331 313 275 340 339 340 195
Parks 56 50 76 111 167 195 69
Schools 36 42 35 66 107 85 91
Other
Construction(2) 0 0 1 32 0 3 0
Public Works(3) 0 0 2 2 2 2 40
Total 1,849 2,064 2,199 3,038 3,884 4,350 3,517
Notes:
(1) Demand from consumption records. Water loss information was not available and not included.
(2) Temporary recycled water customers were primarily construction water and are tabulated separately in billing records (some of CMWD’s summaries of annual demand data may not include this demand category).
(3) Includes street medians, pump station sites, etc.
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As shown in Table 2.2, CMWD’s total demand has steadily increased between 2004 and
2009 due to the implementation of Phase II and the connection of new customers.
However, in 2010 the demand reduced significantly. The reasons for the reduction are
discussed in more detail in Chapter 3, but include the recent economic downturn, increases
in recycled water rates, increased conservation (efficiency), watering restrictions associated
with potable water, and cooler than average weather.
Table 2.2 also shows that CMWD serves most of its recycled water to the Home Owners
Associations (HOAs), Golf Courses, and Commercial Properties for landscape irrigation.
Table 2.3 lists the demands for CMWD’s five largest users. Note that some of the demand
associated with each of the five largest users may be considered multiple use types.
Table 2.3 Largest Existing Recycled Water Customers
Recycled Water Master Plan
Carlsbad Municipal Water District
Customer Name
Average Annual Demand (afy)
2004 2005 2006 2007 2008 2009 2010
La Costa Resort - North Course 167 273 287 178 263 335 272
La Costa Resort - South Course(1) 239 262 250 278 193 198 146
Park Hyatt Aviara Resort(2) 319 298 265 328 320 325 266
Aviara Resort Association 190 168 176 185 184 195 159
Kemper Sports Management(3) 0 0 0 139 396 405 274
Legoland 141 170 141 129 122 137 104
Total Top 5 Users 1,056 1,171 1,119 1,237 1,478 1,595 1,221
Notes: (1) Supplied by Gafner WRP, not connected to the rest of the recycled water distribution system. (2) Named the Four Seasons Resort prior to June 21, 2010. (3) This user represents the golf course “The Crossings at Carlsbad”.
As seen by comparing Table 2.3 to Table 2.2, CMWD’s five largest customers comprise
over one-third of the total demand for 2009 and 2010. As shown, the decline in the overall
system demands is also seen in the five largest users. The locations of CMWD’s five
largest recycled water customers are shown on Figure 2.1.
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2.5 RECYCLED WATER DISTRIBUTION SYSTEM
CMWD supplies recycled water through two recycled water distribution systems. CMWD’s
primary recycled water distribution system consists of five pressure zones, three storage
tanks, three booster pumping stations, two supply sources with pump stations, and three
pressure regulating stations. CMWD also supplies recycled water to the south course of the
La Costa Resort and Spa from the Gafner WRP through a separate distribution system with
dedicated service to the La Costa Resort and Spa. Table 2.4 provides a summary of each
of the facilities within the two distribution systems, while Figure 2.2 illustrates the
connectivity of the various facilities within the distribution system in a hydraulic profile
format.
Table 2.4 Summary of Facilities by Pressure Zone
Recycled Water Master Plan Carlsbad Municipal Water District
Pressure Zone
HGL
Elevations Served
(ft MSL)
Pumping Stations /
Supply Sources(5) Storage(5)
Pressure Regulating
Stations
Annual Demand(6)
(afy)
660 240' to 460' Bressi PS(4) n/a 311
580 200' to 430' Calavera PS(4) n/a 229
550 200' to 430' Twin D PS MWRF(2) Mahr Reservoir 731(1)
384 20' to 380' CWRF Twin D Tanks
C Tank
Faraday PRV
La Costa PRV
Twin D FCV(3)
2,381
318 50’ to 80’ n/a On-site ponds Encinas PRV 39
Gafner 60’ GWRP On-site ponds n/a 194
Notes: PS = Pump Station; HT = Hydro-pneumatic Tank; PRV = Pressure Reducing Valve; PSV = Pressure Sustaining Valve.
(1) Does not include 13.3 afy of demand served in Vallecitos Water District’s service area. (2) Flow from MWRF enters CMWD’s system through the Corintia Meter, which measures the amount of flow provided from MWRF and Mahr Reservoir.
(3) Twin D FCV is also referred to as Ralph Valve. The valve is a combination rate of flow, pressure sustaining, and solenoid control valve, but is controlled by SCADA based on tank level and demand. (4) Pump station includes a hydro-pneumatic tank; pressure zone supplied by this pump station does not include gravity storage. (5) Supply Sources and Storage indicate facilities that are either located in or directly feed the identified zone.
Note that pressure zones utilize storage and supply sources in other pressure zones. See Figure 2.2 for a schematic presentation of the connectivity of zones. (6) Based on year 2008 and obtained from the hydraulic model (see Table 6.1).
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2.5.1 Pipelines
CMWD’s recycled water distribution system includes approximately 77 miles of pipelines
within its service area, ranging in size from 2 to 30 inches in diameter. Table 2.5 presents a
breakdown of pipelines by diameter and material type as of September 2009.
Table 2.5 Recycled Water Distribution System Pipelines
Recycled Water Master Plan
Carlsbad Municipal Water District
Diameter
(in)
Pipeline Length(1) (ft) by Material Class
Total
(ft)
Total
(mi) PVC ACP
CML&C
STL DIP HDPE
2 200 0 0 0 0 200 <0.1
4 28,400 0 100 0 0 28,500 5.4
6 27,400 1,500 1,200 2,200 0 32,300 6.1
8 137,500 400 1,600 1,300 0 140,800 26.7
10 6,500 100 0 0 0 6,600 1.3
12 84,500 10,800 2,100 10,700 0 108,100 20.5
14 0 0 4,600 2,700 0 7,300 1.4
16 8,600 0 200 900 0 9,700 1.8
18 8,200 0 500 8,300 0 17,000 3.2
20 4,500 0 3,500 0 0 8,000 1.5
24 0 0 22,800 0 50 22,850 4.3
27 0 0 4,800 0 0 4,800 0.9
30 0 0 19,300 1,300 50 20,650 3.9
Total (ft) 305,800 12,800 60,700 27,400 100 406,800 -
Total (mi) 57.9 2.4 11.5 5.2 <0.1 - 77.0
Notes:
PVC = polyvinyl chloride; ACP = asbestos cement pipeline; CML&C STL = cement mortar lined and coated
steel; DIP = ductile iron pipeline; HDPE = high density polyethylene.
(1) All lengths are rounded to 100 feet (except for HDPE, which is rounded to the nearest 50 feet for
consistency with categorization of Table 2.6). Data is from CMWD’s pipeline GIS layer as of September 2009.
As shown in Table 2.5, the majority of CMWD’s transmission and distribution mains consist
of 8-inch diameter to 12-inch diameter pipelines (63 percent). The majority of the pipelines
(about 75 percent) are made of polyvinyl chloride (PVC).
According to CMWD’s pipeline GIS layer as updated September 2009, approximately
59 percent of the recycled water distribution system pipelines were installed in the years
2000 through 2009, with less than one percent installed prior to 1985. Figure 2.4
summarizes the pipeline lengths by installation years while Table 2.6 summarizes the
length of pipeline by material and installation year.
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PVC57.9 mi.75%
Asbestos Cement2.4 mi.3%Cement Mortar Lined and Coated Steel
11.5 mi.15%
Ductile Iron5.2 mi.7%
HDPE, <0.1 mi.<1%
PVC AC STL DI HDPE
Figure 2.3 Pipelines by Material Type
Table 2.6 Pipelines by Installation Year and Material Type
Recycled Water Master Plan
Carlsbad Municipal Water District
Material Pipeline Length(1) (ft) by Installation Year(2)
Total (ft) Total (mi) Prior to 1985 1985 to 1994 1995 to 1999 2000 to 2004 2005 to 2010
PVC 800 33,800 77,000 174,400 19,800 305,800 57.9
ACP 100 8,400 500 3,800 0 12,800 2.4
CML&C STL 2,900 6,800 18,500 32,500 0 60,700 11.5
DIP 0 10,900 7,300 9,200 0 27,400 5.2
HDPE 0 0 0 100 0 100 <0.1
Total (ft) 3,800 59,900 103,300 220,000 19,800 406,800
Total (mi) 0.7 11.3 19.6 41.7 3.8 77.0
Notes:
PVC = polyvinyl chloride; ACP = asbestos cement pipeline; CML&C STL = cement mortar lined and coated
steel; DIP = ductile iron pipeline; HDPE = high density polyethylene.
(1) All lengths are rounded to nearest 100 feet. Data is from CMWD’s pipeline GIS layer as of September 2009.
(2) Installation Year based on construction plan signature date from CMWD’s GIS layer.
Total Existing Pipeline Length = 77 miles
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Prior to 1985, 0.7 mi.<1%
1985 to 199511.3 mi.15%
1995 to 200019.6 mi.25%
2000 to 200541.7 mi.54%
2005 to 20103.8 mi.5%
Prior to 1985 1985 to 1995 1995 to 2000 2000 to 2005 2005 to 2010
Figure 2.4 Pipelines by Installation Year
2.5.2 Pumping Stations
CMWD’s recycled water distribution system contains four pump stations, one delivering flow
from CWRF and three pump stations that move water within the distribution system
between pressure zones. In addition, VWD uses a pump station to deliver water from
MWRF to Mahr Reservoir and LWWD uses a pump station to deliver water from GWRP to
a lake for irrigation of the La Costa Resort and Spa south golf course. Table 2.7 lists details
for each pump station.
The Bressi PS is the sole conveyance of recycled water into Zone 660, and consists of
three main pump units and a small 180-gpm jockey pump with a 7.5-hp motor. The Bressi
PS contains a hydro-pneumatic tank, which provides pressure while the pump units are
inactive.
The Calavera PS is the sole conveyance of recycled water into Zone 580, and consists of
three main pump units and a small 50-gpm jockey pump unit with a 5-hp motor. This pump
station contains a hydro-pneumatic tank, which in conjunction with the jockey pump
provides pressure while the three main pump units are inactive and demand is low.
The Twin D PS is located at the site of the Twin D Tanks, and consists of four pump units
pumping from Zone 384 to Zone 550. This pump station is designed to supply the upper
zones of CMWD’s recycled water system from Carlsbad WRF if supply from Meadowlark
WRF is unavailable. The pump station is capable of conveying flow through the Corintia
Meter into Mahr Reservoir.
Total Existing Pipeline Length = 77 miles
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Table 2.7 Pumping Stations
Recycled Water Master Plan Carlsbad Municipal Water District
Pump Station
No. of
Pump Units
Year of
Installation
Suction Zone
or Facility
Discharge
Zone
Design Capacity
(gpm)
Bressi PS 3 + JP(1) 2006 Zone 550 Zone 660 3,000
Calavera PS 3 + JP(1) 2004 Zone 384 Zone 580 1,800
Twin D PS 4 2003 Zone 384 Zone 550 4,500
CWRF PS 3 2002 CWRF Zone 384 10,000
MWRF PS(2)(3) 3 2005 MWRF Zone 550(1) 3,250
GWRPS(4) 2 1991 GWRP La Costa South Golf Course 2,250
Notes: (1) Bressi PS and Calavera PS include jockey pump units for low flow conditions. (2) This pump station feeds Zone 550 and through the Corintia Meter it can also feed Mahr Reservoir.
(3) Owned and operated by VWD. (4) Owned and operated by LWWD.
The Carlsbad WRF PS is located at the Carlsbad WRF and consists of three pump units
that pump into Zone 384. The pump units are sized at 3,330 gpm each. The pump station
design flow of 10,000 gpm requires simultaneous operation of all three pump units. Two
empty pump bays provide space for future expansion of the pump station.
Meadowlark WRF PS consists of three variable frequency drive vertical turbine pump units.
This pump station is not a part of CMWD’s recycled water system and is owned and
operated by VWD. This pump station feeds the Zone 550 through the Corintia Meter and is
designed to pump to Mahr Reservoir.
Gafner WRP PS delivers recycled water to the La Costa Resort and Spa south golf course
lake. It includes two 1,125-gpm pumps with 40-hp motors, one operating pump, and one
standby pump. Water is pumped through a 12-inch diameter pipeline to the lake.
Chapters 6 and 7 contain additional details for each facility and provide a discussion on the
controls used to operate each facility.
2.5.3 Pressure Regulating Stations
Pressure regulating stations (PRS) allow distribution systems to transfer water from higher
pressure zones to lower pressure zones without exceeding the allowable pressures in the
lower zones or completely draining the pressure out of the higher zone. Typically, a PRS
contains pressure reducing valves (PRV), pressure sustaining valves (PSV), pressure relief
valves, or combination valves.
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A PRV conveys water from an upper zone to a lower zone while reducing the pressure to a
specified pressure setting on its downstream side. A PSV maintains a pressure setting on
its upstream side while conveying flow. That is, the pressure sustaining valves will not allow
water to transfer into the lower pressure zone if the pressure in the upper zone drops below
a certain level. This ensures that a main break, or similar emergency, in the lower pressure
zone does not drain too much water from the upper pressure zone. CMWD uses combined
valves, which incorporate both pressure reducing and pressure sustaining features.
Pressure relief valves bleed water from areas of high pressure when pressure exceeds a
certain threshold. CMWD’s pressure regulating stations are configured to discharge from
the lower pressure to atmosphere or into the storm drain if the pressure in the lower
pressure zone gets too high.
CMWD’s recycled water distribution system contains three pressure regulating stations,
which generally convey and regulate the flow of water from higher pressure zones to the
lower zones. Table 2.8 summarizes details of each PRS. The locations of the pressure
regulating stations are shown on Figure 2.1, while the connectivity is shown on Figure 2.2.
Table 2.8 Pressure Regulating Stations
Recycled Water Master Plan Carlsbad Municipal Water District
Name No. of Valves(1) Year of Installation Upstream Zone Downstream Zone Elevation (ft MSL) Setting (psi)
Faraday PRS(3) 3 2003 550 384 220 70
La Costa /
Poinsettia PRS(3) 3 2006 550 384 175 89
Twin D Flow Control Valve(2)(Ralph Valve) 2 2003 550 384 386 13
Avenida Encinas
PRS(3) 2 2001 384 318 58 113
Notes:
(1) Each pressure regulating station includes a pressure relief valve (the Twin D PS also includes a pressure relief valve). The number of valves includes the pressure relief valve.
(2) The pressure regulating station at the Twin D PS acts as an altitude valve, replenishing the Twin D Tanks from
the MWRF and Mahr Reservoir via the Corintia Meter. The valve is a combination rate of flow, pressure sustaining, and solenoid control valve, but is controlled by SCADA based on tank level and demand.
(3) A PSV sustains a set pressure upstream of the valve, while a PRV maintains a set pressure downstream of
the valve. CMWD uses combination pressure reducing and pressure sustaining valves with dual pilot controls at its pressure regulating stations.
As shown in Table 2.8, the Faraday PRV, La Costa PRV, and Twin D PSV supply Zone 384
from Zone 550. These three regulating stations are typically operated to deliver flow from
Meadowlark WRF and Mahr Reservoir via the Corintia Meter. The Avenida Encinas PRV is
the sole conveyance to Zone 318, regardless of the supply source and operating
conditions.
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2.5.4 Corintia Meter
CMWD’s distribution system contains a metering station at the Carlsbad WRF and a
metering station, the Corintia Meter, at the delivery point to CMWD’s distribution system
from VWD’s Meadowlark WRF and Mahr Reservoir. The Corintia metering station consists
of a 16-inch diameter magnetic meter (magmeter) to record flow. There is a 16-inch
diameter plug valve downstream from the meter that can either be opened or closed. This
valve is normally open such that Zone 550 floats off Mahr Reservoir. However, the valve
can be closed under certain conditions to isolate CMWD’s recycled water distribution
system from VWD and Olivenhain Municipal Water District’s (OMWD) recycled water
distribution systems. The Corintia Meter is located in an underground vault near the
intersection of Melrose Drive and Corintia Street as shown on Figure 2.1.
2.5.5 Interconnections
CMWD’s recycled water distribution system currently does not have any emergency
interconnections with recycled water distribution systems of neighboring agencies.
However, the OMWD recycled water distribution system is also connected to Mahr
Reservoir and fed entirely by the Meadowlark WRF. Since the OMWD recycled water
distribution system does not have an additional source of supply, OMWD would not be able
to supply CMWD’s recycled water distribution system in the event of an outage of
Meadowlark WRF. However, CMWD could supply OMWD’s recycled water distribution
system from Carlsbad WRF via CMWD’s recycled water distribution system.
2.5.6 Potable Water Supply Connections
CMWD’s recycled water distribution system currently has one connection from CMWD’s
potable water distribution system to the recycled water distribution system. Potable water is
introduced to the recycled water distribution system at the D Tanks, through the use of an
air gap. The connection is made up of a meter and an 8-inch diameter PSV currently set to
74 psi. According to CMWD staff, the PSV can convey at least 3,000 gpm. The valve is
normally closed and can be operated remotely through SCADA.
VWD also has a potable water supply connection at Mahr Reservoir. Potable water can be
added to the reservoir through an air gap.
2.5.7 System Operations
The primary function of CMWD’s recycled water distribution system is to distribute recycled
water from the water reclamation facilities to CMWD’s customers.
The Meadowlark WRF operates as a skimming plant, reclaiming treated wastewater and
discharging solids to EWPCF through a dedicated 6-inch diameter DIP forcemain to VWD’s
24-inch diameter gravity outfall sewer. VWD operates the Meadowlark WRF PS to supply
recycled water to the system. Flows from Meadowlark WRF depend on the influent flows to
the treatment plant. The variation in influent flows to Meadowlark WRF, the diurnal variation
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of CMWD’s customer demands, and the diurnal variation of OMWD’s customer demands
cause water level changes on a daily basis in Mahr Reservoir. CMWD strives to maintain at
least 15 feet of water in Mahr Reservoir to avoid pressure problems in Zone 550.
In the case where recycled water demand is low and Mahr Reservoir is full, tertiary
treatment can be curtailed and secondary treated water can be pumped through a separate
pumping station to a 12-inch diameter “failsafe” pipeline, which is capable of a peak flow of
3.0 mgd. The secondary treated pump station includes three duty (no standby) pumps rated
at 920 gpm each and with a combined capacity of 1,750 gpm (2.5 mgd) with all three
pumps operating.
The “failsafe” pipeline can also receive flow from the tertiary pumping station through
manually operated valves.
According to the Mahr Reservoir Operations and Maintenance Manual (Carlsbad, 2008),
32 MG of storage within Mahr Reservoir is dedicated to CMWD’s recycled water distribution
system storage needs. This agreement is based on a supply from the Meadowlark WRF of
2.0 mgd during the winter (December through March) and 3.0 mgd during the summer
(April through November).
The Carlsbad WRF treats secondary effluent from the EWPCF for delivery to CMWD’s
recycled water distribution system from the west side of the service area. Recycled water is
supplied to CMWD’s recycled water distribution system by the Carlsbad WRF PS. Under
typical operations, the pump units are controlled by water levels in two of the Twin D tanks.
The Carlsbad WRF PS pulls from two reclaimed water basins totaling 7.5 MG of recycled
water storage. However, a single basin with about 3.75 MG of storage is usually sufficient
for operation of CMWD’s existing recycled water distribution system. The basins have a
dual purpose as these provide buffering capacity to handle peak wet weather flows tributary
to the EWPCF during the winter months and provide additional storage to accommodate
daily irrigation peaking during the summer months for CMWD.
As discussed in more detail in Chapter 3, CMWD’s recycled water distribution system
reaches its peak demands during the evening hours for nighttime irrigation. Based on
discussions with CMWD staff, the typical daily operations pattern is as follows:
• When water levels in CMWD’s storage reservoirs fall, the Carlsbad WRF PS comes
online, supplying the nighttime demand from the Carlsbad WRF equalization basin
and replenishing operational storage.
• As the Twin D tank levels fall, the Twin D Flow Control Valve (Ralph Valve) will open
based on the levels in the Twin D tanks to increase the flow being taken from
Meadowlark WRF and Mahr Reservoir via the Corintia Meter.
• The Carlsbad WRF PS is turned off based on the levels in the Twin D tanks once the
tanks replenish as the nighttime irrigation demands end. However, during peak
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months, the Carlsbad WRF PS will be run all night to take advantage of non-peak
time-of-use electrical rates to lift supply from Carlsbad WRF to the storage tanks to
avoid pumping during peak time-of-use electrical rates.
• The Twin D Flow Control Valve (Ralph Valve) is left active until the totalized flow
through the Corintia Meter reaches the allotment for the day or the operational
storage is replenished. After SCADA closes the Twin D Flow Control Valve (Ralph
Valve), the distribution system is supplied from operational storage and is
supplemented by the Carlsbad WRF, if necessary.
Recycled water demands in Zones 660 and 550 are typically supplied exclusively by
Meadowlark WRF and Mahr Reservoir via the Corintia Meter throughout the day, as
Zone 550 uses Mahr Reservoir for operational storage. In addition, some of the demands in
Zone 384 are supplied from Meadowlark WRF and Mahr Reservoir when the Twin D Flow
Control Valve, Faraday PRV, and La Costa PRV are open. The remaining demands in
Zones 384, 318, and 580 are supplied from Carlsbad WRF. Once the daily allotment from
Meadowlark WRF has been reached, the Twin D Flow Control Valve is closed.
If Meadowlark WRF and Mahr Reservoir are not able to supply the system, the flow
direction can be reversed so that the Carlsbad WRF PS and the Twin D PS can supply the
system.
Gafner WRP exclusively serves the La Costa Resort south golf course. The golf course
provides limited operational storage through lakes within the golf course. Since the La
Costa Resort is the only customer supplied by Gafner WRP, the pump station is controlled
based on the demands of the golf course (via lake level).
2.6 ABANDONED FACILITIES
CMWD has also identified several abandoned pipelines within its potable water distribution
system that may prove useful to convey recycled water. These pipelines are shown on
Figure 2.5. Although the condition of these pipelines is unknown, CMWD staff has indicated
that it may be possible to utilize some of these abandoned pipelines by inserting a smaller
diameter pipeline within the existing abandoned pipeline such that the existing abandoned
pipeline is used as a casing. Based on discussions with CMWD staff, the following two
abandoned potable water pipelines should be considered when evaluating future system
expansions of the recycled water distribution system:
• A 27-inch diameter pipeline along Palomar Airport Road and east of El Camino Real
is abandoned and extends to the Santa Fe I Tank beyond the City boundary. The
pipeline within the service area is approximately 1.9 miles in length. The currently
abandoned potable water Santa Fe I Tank could potentially be utilized for storage for
the recycled water system. However, portions of this pipeline have been destroyed.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" Tanks
Aviara Pkwy
Calavera PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
Avenida Encinas PRS
La Costa PRS
OMWD Meter
Corintia Meter
Faraday PRS
"E" Tank(302' HWL)
Sante Fe I Tank(600' HWL)
T a m a r a c k A v e El Cami
no Re
al
Encinitas
Oceanside
LakeCalavera
Buena Vista Reservoir
and Tank (186' HWL)14''2
0''
2 7 ''6''10''1
0
''
20''20''20''
2
0''
1
0
''
Legend
Recycled Pipelines by Pressure Zone
318
384
550
580
660
Recycled Water Facilities
WRF
Tank
Reservoir
Inactive WRP
Meter
Pump Station
Pressure Regulating Station
Other
Freeways
Local Streets
Carlsbad Municipal Water District Boundary
Water Body
Carlsbad City Limits
San Diego County
Abandoned Potable Water Facilities
Abandoned Pipeline
0 5,000 10,000
Feet
Figure 2.5Abandoned Potable
Water FacilitiesRecycled Water Master Plan
Carlsbad Municipal Water District
8
"12"FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_2_4-Abandoned Pipelines Ver B.mxdDATE: 5/10/201124"
Abandoned Tanks
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• A large number of 20-inch diameter pipeline segments with a combined length of
approximately 5.3 miles along El Camino Real are abandoned and could potentially
be rehabilitated or used to convey flow northwest towards the Rancho Carlsbad Golf
Course.
In addition, the following storage reservoirs could potentially be converted to the recycled
water system:
• BV Tank is a 10,000-gallon welded steel tank constructed in 1972, currently in use as
a forebay for a potable water pump station located in the northeast quadrant at Buena
Vista Way at James Drive. The tank is at ground elevation 223 feet above mean sea
level (ft-msl) on a 2.8-acre parcel owned by the City of Carlsbad.
• BV Reservoir is an abandoned concrete lined open reservoir located in the northeast
quadrant at Buena Vista Way at James Drive. The reservoir is approximately 310 feet
by 120 feet at the top and 270 feet by 90 feet at the bottom with a base elevation of
180 ft-msl and a top elevation of 190 ft-msl. Overflow is approximately 186 ft-msl.
Capacity is 1.4 MG. Utilization of this reservoir for storage of recycled water is limited,
due to the residential nature of the neighborhood and potential odor problems.
• E Tank is a 1.5-MG reservoir located at the north end of Crossing Drive currently
serving the potable water system. This reservoir sits at an elevation of 264 ft-msl with
a high water line (HWL) at 302 ft-msl. The hydraulics of the zone it belongs to within
the potable water system are such that the entire capacity of the reservoir is not able
to be used. Due to its elevation, the only zone within the recycled water distribution
system for which it could prove useful is on the west side of Interstate 5.
• Santa Fe I Tank is located east of CMWD’s service area, north of Palomar Airport
Road a little over a mile east of Melrose Drive. This reservoir is currently abandoned
after it was replaced with a new potable water reservoir located along White Sands
Drive called Santa Fe II. It is a 2.5-MG prestressed concrete tank at a hydraulic grade
line of 660 ft-msl. Santa Fe I is connected to the 27-inch diameter abandoned potable
water pipeline along Palomar Airport Road; however, portions of this pipeline have
been destroyed.
• Lake Calavera is an open reservoir dam east of College Boulevard and south of Lake
Boulevard. The primary function of the reservoir is stormwater retention and flood
control. The water surface elevation is maintained at 208 ft-msl. The reservoir is able
to operate between 190 ft-msl to 214 ft-msl, providing a storage volume of 480 MG.
Currently, the reservoir water level is either drawn down to accommodate flood control
needs or allowed to accumulate to increase surface elevation. In the future, the
reservoir could potentially provide stormwater for a satellite treatment plant that would
treat Lake Calavera water for distribution in the recycled water system.
The potential beneficial use of these abandoned potable water facilities and pipelines is
evaluated as part of the future system analysis, which is discussed in Chapter 9.
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2.7 KNOWN SYSTEM DEFICIENCIES
2.7.1 Limited Supply from MWRF
As discussed previously, the MWRF has a design capacity of 5.0 mgd, but currently
supplies a maximum of about 3.4 mgd. The supply provided by the MWRF is limited to the
upstream wastewater flow tributary to the MWRF plus wastewater diverted through VWD’s
Lift Station Number 1. This 3.4-mgd supply limitation has had an effect on the amount of
recycled water being supplied to CMWD and OMWD as well as the flow to storage in Mahr
Reservoir. MWRF is also limited by a 3.0-mgd “failsafe” pipeline. When the MWRF supply
has been limited in the past, VWD has supplemented with potable makeup water supplied
to Mahr Reservoir to meet OMWD demand.
2.7.2 Water Quality Issues at Mahr Reservoir
CMWD staff has noted water quality problems at Mahr Reservoir due to algae and other
biological growth. To mitigate algae growth, the reservoir has an algae control chlorination
system as well as an aeration and destratification system, which mixes the reservoir. In
addition, sodium hypochlorite and/or copper sulfate are used to improve water quality.
2.7.3 Calavera Pump Station
Due to the limited storage and demand in Zone 580, the Calavera PS has experienced
some operational and control issues. The pump units used to turn on frequently for short
durations of time, either to replenish the 1,600-gallon hydro-pneumatic tank or meet low
demands. Due to the hourly variability of demands, the pumps need to cycle on and off
frequently. To mitigate this issue, CMWD recently installed a smaller 50-gpm capacity
jockey pump that can run more continuously during the low demand hours and prevent the
wear and tear on the large pump unit due to frequent on/off cycling.
2.7.4 Bressi Pump Station
CMWD staff noted that the Bressi PS experiences similar operational and control issues as
Calavera PS. CMWD staff installed a 180-gpm capacity jockey pump to the Bressi pump
station that can run continuously during the low demand hours and prevent the wear and
tear on the large pump units due to frequent on/off cycling.
2.7.5 Gafner WRP
CMWD staff have stated that the aging nature of the Gafner WRP has led to a number of
operational issues. The Gafner WRP exclusively serves the demand at the south golf
course of the La Costa Resort and Spa. As the demand at the golf course is variable, the
Gafner WRP has frequent startups and shutdowns that most likely exacerbate the
operational issues that CMWD currently pays to resolve. In addition, the Gafner WRP is not
optimally utilized since the south golf course demand is far less than the minimum amount
of recycled water that CMWD is required to purchase from the LWWD. To further
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compound the problem, the La Costa Resort and Spa further reduces recycled water
demand to its south golf course by blending Gafner WRP effluent with potable water to
decrease TDS concentrations for irrigation of golf course tees and putting greens. In the
past, golf course tees and putting greens were irrigated with the same system as fairway
sprinklers.
Discussions with the golf course operations manager of the La Costa Resort and Spa in
2010 indicated that they are planning on significant changes, which include reducing the
amount of irrigated turf, and piping potable water directly to the greens and tees. These
changes will further reduce their irrigation demand on the recycled water supply.
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Chapter 3
RECYCLED WATER DEMANDS
3.1 INTRODUCTION
This chapter presents a discussion of the estimated recycled water demands on Carlsbad
Municipal Water District’s (CMWD) recycled water distribution system. CMWD’s historical
recycled water demand is presented first, followed by a discussion of the recycled water
demand factors and peaking factors that are used to estimate the recycled water demands
of potential future recycled water customers. This chapter is concluded with a discussion of
the recycled water demand projections, which includes a summary of the evaluation of
potential customers that was conducted as part of this Recycled Water Master Plan
(RWMP). Demands for potential customers both inside and outside CMWD’s service area
are discussed. Details of each of the potential customers can be found in Appendix C.
3.2 BACKGROUND
As discussed in Chapter 2, CMWD’s recycled water distribution system has been
developed in phases. Planning for Phase I began in 1990, with CMWD’s first recycled water
master plan. Phase I was fully implemented by 1995 and planning for Phase II was initiated
with the 1997 Master Plan Update. Table 3.1 presents details for each of CMWD’s phases,
along with the years of construction for major infrastructure associated with each expansion
phase.
Table 3.1 Phases of Distribution System Expansion
Recycled Water Master Plan
Carlsbad Municipal Water District
Phase
Ultimate Yield
(afy)
Major Elements
Constructed
Years When Customers Were
Connected
Number of
Customers
Phase I 2,050 1993 - 1994 1993 - 1999 120(1)
Phase II(2) 2,950 2004 - 2009 2006 - 2010 242(3)
Notes:
(1) Based on Encina Basin Recycled Water Study (JPA, 2000).
(2) Connection of Phase II customers is ongoing. Based on input from CMWD staff, it is anticipated that the combined Phase I and Phase II goal of 5,000 afy will be met in 2012.
(3) Based on 362 total customers (675 meter accounts) in December 2010 billing data.
CMWD’s agreement with Metropolitan Water District of Southern California (MWD)
specifies targets for demands CMWD serves related to CMWD’s eligibility for the Local
Resource Program (LRP) contributions from MWD. The LRP contributions are paid to
CMWD based on the actual demand served and range from $210 down to $100 per
acre-foot served.
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The targets are comprised of a Targeted Yield and a Maximum Annual Allowable Yield. The
Targeted Yield is the minimum amount of recycled water that CMWD must serve within a
subset of the period of agreement (the targeted yields and subsets are shown in
Figure 3.1). The Maximum Annual Allowable Yield is the maximum amount of demand
eligible for the LRP contribution in a given year. If CMWD does not reach the Targeted
Yield within the subset of the period of agreement, the Maximum Annual Allowable Yield
will be reduced. The Ultimate Yield is the Maximum Annual Allowable Yield for Fiscal Year
2008-09 and beyond (prior to Fiscal Year 2008-09, the Maximum Annual Allowable Yield
increased each year until it reached the Ultimate Yield).
Figure 3.1 presents CMWD’s Targeted and Maximum Annual Allowable Yields along with
historical demands for the calendar years 2004 through 2010 based on customer billing
data.
0
1,000
2,000
3,000
4,000
5,000
6,000
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018Annual Demand (afy)Calendar Year
Historical Annual Demand Targeted Yield Maximum Allowable Yield
4,262 afy3,908 afy
3,142 afy
Ultimate Yield 5,000 afy
Figure 3.1 MWD Target and Ultimate Yield compared to Historical Demands
As shown in Figure 3.1, CMWD met the Targeted Yield in 2008 and 2009. This figure also
shows that CMWD has maximized its LRP contribution in 2008 and 2009 by exceeding the
Ultimate Yield. As shown in Figure 3.1, the demand in 2010 decreased from the demands
seen in 2008 and 2009. It should be noted that the MWD agreements are based on fiscal
year rather than calendar year, so the data shown in Figure 3.1 may not reflect actual
historical comparisons between the demand served and the relevant targets. More details
on the LRP agreement with MWD can be found in the original agreement document, which
is included in Appendix D of this report.
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3.3 HISTORICAL RECYCLED WATER DEMAND
CMWD’s existing recycled water customers used a total of 3,517 acre-feet (3.1 mgd) in
calendar year 2010. CMWD’s average annual historical recycled water demands obtained
from billing records for calendar years 2004 through 2010 are summarized in Table 3.2.
Table 3.2 Historical Recycled Water Demands
Recycled Water Master Plan Carlsbad Municipal Water District
Usage Category
Average Annual Demand(1) (afy)
2004 2005 2006 2007 2008 2009 2010
Ag. Irrigation 0 0 0 0 0 0 23
Process Water 0 0 0 0 0 0 0
Landscape Irrigation
Commercial Property
Irrigation 382 427 410 561 827 1,074 637
Community Facilities 8 9 11 13 17 27 49
Golf Courses 596 703 713 780 1,036 1,133 1,033
Highways 52 52 31 46 28 25 11
HOAs 388 468 645 1,087 1,361 1,466 1,369
Resort Irrigation 331 313 275 340 333 340 195
Parks 56 50 76 111 167 195 69
Schools 36 42 35 66 107 85 91
Other
Construction(2) 0 0 1 32 0 3 0
Public Works(3) 0 0 2 2 2 2 40
Total 1,849 2,064 2,199 3,038 3,878 4,350 3,517
Notes:
(1) Demand from consumption records. Water loss information was not available and not included.
(2) Temporary recycled water customers were primarily for construction water and are tabulated separately
in billing records (some of CMWD’s summaries of annual demand data may not include this demand category).
(3) Includes street medians, pump station sites, etc.
CMWD’s current recycled water customers were divided into four categories of user types
and ten sub-categories, each of which is listed in Table 3.2. As shown in Table 3.2, the
landscape irrigation category represents the largest component of CMWD’s demands. This
reflects the current nature of CMWD’s recycled water system customer base. CMWD
currently does not have any non-irrigation usage type recycled water customers, but is
planning to implement some non-irrigation usages in the near future.
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3.3.1 Historical Demand Trends
The historical demands from 1992 through 2010 are shown on Figure 3.2.
0
1,000
2,000
3,000
4,000
5,000
1992199319941995199619971998199920002001200220032004200520062007200820092010Demand (afy)Year
Figure 3.2 Historical Recycled Water Demands
As seen in Figure 3.2, CMWD’s demands have grown consistently through year 2009, while
demands decreased in 2010. Between 2004 and 2009, recycled water demands increased
from 1,849 afy (1.7 mgd) to 4,350 afy (3.9 mgd), an increase of 235 percent corresponding
to an average annual growth rate of about 19 percent. The primary reason for this growth
trend between 2004 and 2009 is the extensive and continued efforts of CMWD to convert
and connect new customers to the recycled water system. The growth between 2006 and
2008 was due to the efforts associated with the Phase II expansion of CMWD’s recycled
water system.
However, as shown in Figure 3.2, the annual demand decreased to 3,517 afy (3.1 mgd) in
2010. Several reasons are believed to contribute to the significant decline in 2010
demands, including higher than average precipitation in 2010, increased water
conservation, CMWD staff’s inspection and auditing practices, recent increases in recycled
water rates combined with the economic downturn.
As presented in Table 3.3 and Figure 3.3, the same demand decrease in 2010 is observed
for CMWD’s five largest customers. This is noteworthy as it indicates a decline in recycled
water usage by CMWD’s largest users, such as La Costa Resort South Golf Course and
Legoland, who have historically formed CMWD’s base demand. Discussions between
CMWD and some of its large recycled water customers clarified the demand reduction as
January 2012 3-5 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
some of the customers indicated that they reduced recycled water usage through, for
example, redesign of their golf courses or other irrigated areas by replacing irrigated turf
with lower demand landscaping. In addition, some golf course customers indicated that they
made adjustments to their irrigation practices to maintain water quality.
Table 3.3 Largest Existing Recycled Water Customers Recycled Water Master Plan
Carlsbad Municipal Water District
Customer Name
Average Annual Demand (afy)
2004 2005 2006 2007 2008 2009 2010
La Costa Resort - North Course 167 273 287 178 263 335 272
La Costa Resort - South Course(1) 239 262 250 278 193 198 146
Park Hyatt Aviara Resort(2) 319 298 265 328 320 325 266
Aviara Resort Association 190 168 176 185 184 195 159
Kemper Sports Management(3) 0 0 0 139 396 405 274
Legoland 141 170 141 129 122 137 104
Total Top 5 Users 1,056 1,171 1,119 1,237 1,478 1,595 1,221
Notes:
(1) Supplied by Gafner WRP, not connected to the rest of the recycled water distribution system.
(2) Named the Four Seasons Resort prior to June 21, 2010.
(3) This user represents the golf course “The Crossings at Carlsbad”.
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
2004 2005 2006 2007 2008 2009 2010Demand (afy)Year
Top 5 Users Other Users
Figure 3.3 Existing Recycled Water Average Annual Demand
3-6 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
3.3.2 Existing Demand
Locations for CMWD’s existing recycled water customer meters (as of June 2009) are
shown on Figure 3.4. As of December 2010, CMWD served approximately 362 customers
through 675 meter accounts.
As discussed previously, CMWD’s recycled water demand in year 2010 was 3,517 afy,
which was a significant reduction of nearly 20 percent compared to the demand of 4,350 afy
in 2009. As this reduction is most likely caused by several factors that are both temporary
and permanent in nature, it was decided that neither the demand of 2009 nor 2010 would
provide a good planning basis as the existing system demand.
Some of the temporary reasons that could have contributed to the demand decrease in
2010 include the absence of a hot summer and above average precipitation. Data from the
California Department of Water Resources (DWR) confirms that the total precipitation in
2008 and 2009 were below average, while total precipitation in 2010, as well as 2011 year-
to-date, were above average.
Other temporary factors include the economic downturn and the statewide water shortage
conditions. Both conditions have resulted in increased water awareness and increased
water conservation efforts for both potable and recycled water usage. It is anticipated that
most of the water conservation efforts are more permanent in nature as some customers,
such as the La Costa golf course, is undergoing a re-design to reduce the amount of
irrigated turf. In addition, recent and future rate increases will continue to motivate
customers to modify their landscaping and irrigation practices to conserve water and save
cost on a permanent basis.
To establish a sound planning basis for the existing demand that is not based on extreme
low year like 2010, but still takes permanent changes in water usage into account, the
demands of the previous two years were evaluated in more detail. It was noted that when
demands were compared from summer to summer rather than by calendar year, the
demand in the period July 2009 through June 2010 (3,940 acre-feet) was very similar to the
demand in the June 2010 through May 2011 (3,970 acre-feet). This shows that when the
“dry” winter of 2009 is eliminated and two similar “wet” winters are compared, the demands
were actually very consistent. Based on this observation and discussions with CMWD staff,
it was decided to use 4,000 afy as the existing system demand.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" TanksEl Cami
no Real
E lm A v e
Marron Rd
C
arls
b
a
d B
lv
d
H
i
g
h
la
n
d Dr
A lo n d ra W a y
Paseo NorteC ollege B lvdPalomar Airport
Aviara Pkwy El Fuerte StCosta Ave
P o in s e ttia L n
T a m a r a c k A v e
Cannon Rd
Calle BarcelonaRanch o Santa FeCalavera PS
Bressi PS
"D" Tank PS
Pacific Ocean
Encinitas
Batiquitos Lagoon
Buena Vista
Lagoon OceansideLakeCalavera
Corintia Meter
OMWDMeterEl Camino RealP o in s e t tia L n
San Marcos
Vista
Encinitas
Oceanside Legend
Recycled Water Pipelines (by Diameter)
Less than 6"
6" to 8"
10" to 14"
16" and larger
Existing Recycled Water Customer
Existing Recycled Water Customer
Recycled Water Facility
Pump Station
Pressure Regulating Station (PRS)
Meter
WRF
Tank
Reservoir
Other
Freeways
Major Roads
Local Streets
Water Body
Carlsbad City Limits
San Diego County
Carlsbad Municipal Water District Boundary
0 5,000 10,000
Feet
Figure 3.4Existing Recycled Water CustomersRecycled Water Master Plan
Carlsbad Municipal Water District
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_3_03-Existing_Recycled_Water_Customers.mxdDATE: 4/15/2011
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3.4 SEASONAL AND HOURLY PEAKING FACTORS
Peaking factors are used to estimate water demands for conditions other than average
annual demand (AAD) conditions. Peaking factors were used to account for fluctuations in
demands on a seasonal and hourly basis.
3.4.1 Seasonal Peaking Factor
As discussed previously, the makeup of CMWD’s existing recycled water customer base is
entirely irrigation in nature. During hot summer days, water use is typically higher than on a
cold winter day because of increased irrigation demands. Common peaking factors include
multipliers to scale AAD to Maximum Day Demand (MDD), Maximum Month Demand
(MMD), and Minimum Month Demand (MinMD) conditions. In recycled water systems, the
MDD factors are typically similar to MMD factors as irrigation sprinkler systems are often
changed on a seasonal basis, rather than a daily basis, unless moisture sensors are used.
Additionally, data for MDD conditions is difficult to estimate on a per user basis, since billing
data is only collected monthly for each user.
Based on the historical data from CMWD, a maximum month peaking factor for irrigation
customers was estimated. Table 3.4 displays a summary of historical information used in
the development of a MMD peaking factor including the AAD and the MMD for years 2004
through 2009.
Table 3.4 Historical Seasonal Peaking Factors
Recycled Water Master Plan
Carlsbad Municipal Water District
Calendar Year
Average
Annual Demand
(mgd)
Maximum
Month Demand
(mgd)
MMD Peaking
Factor
Individual
Customers MMD Peaking
Factor Range(1)
2004 1.65 3.27 2.0 1.1-2.5
2005 1.84 3.28 1.8 1.2-3.7
2006 1.96 3.24 1.7 1.1-4.8
2007 2.71 4.04 1.5 1.1-6.5
2008 3.46 5.34 1.5 1.2-6.0
2009 3.89 5.78 1.5 1.1-10.5
Average 1.7
Note:
(1) In calculation of range of individual customers seasonal peaking factors, the following assumptions were made: minimum seasonal peaking factor excludes any accounts with seasonal peaking factors of zero (primarily inactive or closed accounts); maximum seasonal peaking factors are taken
as the 95th percentile of all individual seasonal peaking factors to exclude erroneous factors, primarily from temporary accounts or large accounts being connected part way through a year.
3-10 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Note that demands for La Costa Resort north and south courses were included in the
demands shown in Table 3.4; thus, the supplies from Gafner WRP are factored into the
calculation of seasonal peaking. If the La Costa Resort south course, and thus Gafner
WRP, is excluded from the calculation, the average MMD peaking factor is 1.6.
Table 3.4 shows that MMD peaking factors range from 1.5 to 2.0 over the six-year period
from 2004 to 2009. Variations for each year could be attributed to differing weather
conditions and rainfall distribution. However, as shown in Table 3.4, the MMD has showed
a decreasing trend over the last five years. This trend is most likely caused by the peak
attenuation effect of increasing system size and number of customers. The effect of one or
two large customer’s water usage on the overall system demand decreases over time when
more small and midsize customers are added. In addition, the smaller demand customers
are typically less likely to adjust the timing of irrigation systems on a daily or weekly basis,
but rather adjust irrigation times more on a seasonal basis.
Looking to the future, the decreasing trend appears be a sustained behavior rather than a
temporary adjustment to drought conditions. Thus, it is recommended that the MMD
peaking factor used in this study be based on the average factor of the six-year period,
rather than the maximum value. Hence, a MMD peaking factor of 1.7 is used in this study
for the existing and future system evaluations described in Chapters 8 and 9, respectively.
Table 3.4 also shows the MMD peaking factor for individual customers. The values
demonstrate that seasonal peaking for some specific customers can be quite different in
nature from the system as a whole, as some customers irrigate at a much higher level
during the summer months than the system-wide average, while some customers irrigate
more consistently throughout the year.
Figure 3.5 shows the monthly seasonal peaking factors for the calendar years 2004 through
2009. Weather data including the average daily high temperature for each month and the
average monthly precipitation are also included on Figure 3.5 for reference. Weather record
summaries were obtained from the Western Regional Climate Center (WRCC, 2010).
As shown in Figure 3.5, the seasonal peaking factor is generally highest in the month of
August, but in some years is higher in the month of July or September. The seasonal
peaking factor is highest in the summer due to the increased irrigation demands during
periods of higher temperatures and less precipitation.
The months with minimum usage are most frequently January and February. The minimum
seasonal peaking factor is used to calculate MinMD and is used primarily for water quality
analysis. For this study, the minimum seasonal peaking factors were taken as the average
of minimum seasonal peaking factors for each year, and were calculated to be 0.2,
indicating that the average daily demand during MinMD conditions can be calculated as
20 percent of the AAD. Thus, the existing system MinMD demand can be calculated as
0.8 mgd.
January 2012 3-11 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
If CMWD connects more customers from non-irrigation and non-weather dependent
customers, such as industrial process or cooling towers, it is expected that the seasonal
MMD peaking factor would decrease as these non-irrigation customers typically use a more
constant amount of water throughout the year.
2.16 2.10
1.68
0.94
0.23
0.09 0.03 0.09
0.23
0.41
1.03
1.48
63.4 63.0 63.5
64.8
66.3 68.5
72.2
73.9 73.3
71.1
68.0
64.6
30
35
40
45
50
55
60
65
70
75
80
0.0
0.5
1.0
1.5
2.0
2.5
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Temperature (degrees Fahrenheit)Monthly Demand / Average Annual Demandor Average Precipitation (inches)Average Rainfall 2004 2005 2006 2007 2008 2009 Average High Temperature
Average Daily High Temperature
Average Monthly Precipitation
Peaking Factors
Figure 3.5 Recycled Water Peaking Factors by Month
3.4.2 Hourly Peaking Factors and Diurnal Curves
Regular variations in water demands also occur during a 24-hour period. Recycled water
systems are characterized by substantial variations in demand during the day. Recycled
water systems and areas that have substantial outdoor irrigation typically experience peak
demand periods late at night through the early morning hours. This is especially true for
CMWD’s customers, as irrigation in publicly accessible areas without supervision is limited
to the period between 10 p.m. and 6 a.m. in accordance with CMWD rules and regulations
for the use of recycled water. This is in contrast with potable water systems with a
significant residential component, which often experience two periods of peak use, the first
in the morning between 6 a.m. and 8 a.m. and the second in the early evening between
5 p.m. and 8 p.m.
3-12 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Since diurnal demand patterns for individual users can vary depending on their usage
types, several usage-based diurnal demand patterns were developed from demand data
gathered for the calibration portion of this study. Figure 3.6 through Figure 3.8 present the
diurnal curves used in this study for the different types of irrigation customers. It is assumed
that future irrigation customers will follow similar diurnal demand patterns.
The diurnal curve shown on Figure 3.6 represents a usage pattern of customers that irrigate
for about 12 hours per day. This usage pattern represents golf course irrigation occurring
during daytime hours. The diurnal curve shown on Figure 3.7 represents a usage pattern of
customers that irrigate for a very short period in the late evening hours. Since the duration
of irrigation is only about 3 hours per day, the peaking factor is 8.0. Figure 3.8 shows the
estimated diurnal variation for typical users within the system. This diurnal curve was
generated during the hydraulic model calibration and is discussed in further detail in
Chapter 6.
0.0
0.5
1.0
1.5
2.0
2.5
0 2 4 6 8 10 12 14 16 18 20 22 24Demand RatioTime
Figure 3.6 Daytime Irrigation
January 2012 3-13 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Figure 3.7 3-Hour Evening Irrigation
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0 2 4 6 8 10 12 14 16 18 20 22 24Demand RatioTime
Figure 3.8 Other Irrigation Users
3-14 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
It should be noted that data on actual diurnal variation for individual customers was not
gathered as a part of this study; rather these diurnal demand patterns were developed
based on system-wide data and discussion with CMWD staff about specific users’ hours of
irrigation. Depending on the actual durations of irrigation, peaking factors for individual
customers may be significantly higher, resulting in much more stress on the distribution
system (i.e., if a customer irrigates for one hour instead of eight hours, the associated
maximum hourly peaking factor for the day would be 24.0 rather than 3.0).
CMWD’s Engineering Design Standards (CMWD, 2008) plan for usage of 8 hours per day
(typically from 10 p.m. to 6 a.m.), resulting in a maximum hourly peaking factor for the day
of 3.0. Within CMWD’s distribution system, commercial and irrigation customers primarily
use water for irrigation and would follow the irrigation based demand patterns.
CMWD may need to implement forms of demand management in the future to better utilize
existing infrastructure while increasing the overall system demand. One way to decrease
the maximum hourly peaking factor is to work with large customers to develop on-site
storage capabilities, such as golf courses with lakes. These customers can take irrigation
water during off-peak hours to replenish their on-site storage and pump from their storage
facilities to meet peak demands without placing a peak demand on CMWD’s distribution
system.
3.4.3 Summary of Peaking Factors
A summary of the peaking factors used in this master plan is presented in Table 3.5.
Table 3.5 Peaking Factors Recycled Water Master Plan
Carlsbad Municipal Water District
Demand Condition Peaking Factor
Average Day Demand (ADD) 1.0 x ADD
Maximum Month Demand (MMD) 1.7 x ADD
Minimum Month Demand (MinMD) 0.2 x ADD
Peak Hour Demand
8-hour irrigation 3.0 x MMD or 5.1 x ADD
3-hour irrigation 8.0 x MMD or 13.6 x ADD
3.5 RECYCLED WATER DEMAND PROJECTIONS
The future recycled water demand projections are based on a combination of a review of
the existing recycled water customers and the identification of potential future recycled
water customers. This section describes the methodology used to project the future
demand potential including the customers identified in the customer database workshop,
and concludes with a future demand summary.
January 2012 3-15 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
It should be noted that the future demands described herein do not necessarily represent
the actual future demands. This section is limited to identifying the future demand potential.
The system analysis (see Chapter 9) determines the feasibility of serving these customers
and identifies the preferred pipeline alignments to expand the existing recycled water
system that will only serve a portion of the potential customers described in this chapter.
3.5.1 Methodology
To estimate CMWD’s future recycled water demand, a list of potential recycled water
customers was prepared using a combination of the following sources:
• Historical potable water billing records;
• Locations of parks and schools within the City’s GIS as well as parks and schools
within neighboring agencies near CMWD’s boundary;
• Discussions with CMWD staff;
• Aerial photographs (which were searched for large, irrigated areas and business
parks); and
• Studies from neighboring agencies:
– Vista Irrigation District Water Reclamation Master Plan (CDM, 1993)
– Vallecitos Water District 2002 Water, Wastewater, and Water Reclamation
Master Plan Update (KJ, 2005)
– Olivenhain Municipal Water District Northwest Quadrant Recycled Water Study
(Boyle, 2004)
From this list, the most relevant potential users were included within the potential customer
database. Phase III customers will then be selected from the customer database based on
the expansions segments developed in Chapter 9. It should be noted that recent behavior
changes by CMWD’s customers have resulted in lower future demands than seen in
historic billing records and previous demand estimates from planning documents. CMWD
staff reviewed the demand projection for each potential customer and refined the overall
demand estimates to be more consistent with the reduced demands seen more recently
and local knowledge of CMWD’s customer base.
In addition, planning summaries for future developments from the City’s Planning
Department were used to determine areas of potential development not included in the list
of potential recycled water customers. Water demand factors for generic categories of
recycled water usage were calculated from areas of development using historical demands.
Ultimate demands were then projected by applying the water demand factors to the areas
of potential development.
3-16 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
3.5.2 Potential Customers
Based on review of the available information and discussions with CMWD staff at the
customer workshop, a list of 161 potential new large recycled water customers was
developed. The customers were separated into the same seventeen categories and
subcategories identified for the existing system, which are described in more detail below.
These categories and subcategories are:
• Agricultural Irrigation
• Commercial or Industrial Process Water
– Industrial
– Commercial Cooling
• Landscape Irrigation
– Commercial Property Irrigation
– Community (Churches, etc.)
– Golf Courses
– Highways
– Home Owners Association (HOA)
– Parks
– Resort Property Irrigation
– Schools
• Other (Mobile Home Park, Public Works)
– Construction
– Public Works
– Pond Evaporation
Note that some of these categories did not have any identified potential customers, but are
included for consistency with the existing system customer base. The locations of these
customers are shown on Figure 3.9 through Figure 3.11, while a detailed list with the
estimated potential recycled water demand for each customer is listed in Appendix C.
It should be noted that the category Highway Irrigation is used in the existing recycled water
system, but no potential customers were identified in this category.
Agricultural Irrigation
CMWD has several agricultural areas that could potentially be served with recycled water.
Typically, the demands for this use are high and these connections are desirable. However,
many of these agricultural areas within CMWD are temporary since HOAs and other
developments are planned for these sites in the future.
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" TanksCamino RealElm AveMarron Rd
Ca
rls
b
a
d
Bl
v
d Hig
hl
a
n
d
D
r
A lo n d r a W a y
Paseo NorteCollege B lvdPalomar Airport
Aviara Pkwy El Fuerte StCosta Ave
P o in s e ttia L n
T a m a ra c k A v e
Cannon Rd
Calle Barcelona
Ran ch o Santa Fe
Calavera PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
Vallecitos Water District
Vista Irrigation District
LakeCalavera
C116
C119
Corintia Meter
OMWDMeter
San Marcos
Vista
Encinitas
Oceanside
C155
C152 C151
C149
C148C146
C145C144
C143
C102
C123
C103
C112
C101
C105
C111
C114
C129
C134
C139
C121C117
C124
C115
C113
C128
C108
C127
C118
C142
C122
C131C120
C133
C107
C140
C141
C137
C132
C135
C104
C005 C009
C001
C055
C062
C087
C010
C088
C042
C056
C044
C041
C034
C068
C173
C060
C063
C037
C040
C045 C067
C003
C020
C027
C026
C035
C002
C004
C012
C021
C025
C038
C036
C072
C157
C156
C154C153
C150
C147
C130
C109
C008
C051
C043
C163
C078
C018
C070
C047
C046C011
C014
C172
C013
C033
C090
C006
C029
C028
C165
C158
C126
C178
C175
C176 C164
C174
C162
C161
C166
C167
C177 C168
C170
C169
C171
C017
C179
Legend
Recycled Water Pipelines (by Diameter)
Less than 8"
10" to 14"
16" and larger
Potential Recycled Water Customers
Agricultural Irrigation
Landscape Irrigation
Commercial or Industrial Process Water
Other
Water System Fcilities
Pump Station
Pressure Requlating Station (PRS)
Meter
WRF
Tank
Reservoir
Inactive WRP
Other
Freeways
Major Roads
Local Streets
Water Body
Customer Parcel
Carlsbad City Limits
San Diego County
Carlsbad Municipal Water District Boundary
0 5,000 10,000
Feet
Figure 3.9Potential Large RecycledWater CustomersRecycled Water Master Plan
Carlsbad Municipal Water District
See Figure 3.10
See Figure 3.11
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_3_8-Large_Potential_Customers.mxdDATE: 4/15/2011
3-18 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
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18
''
3 0 ''1
8''
1
2''12'
'24''
8''
1 2 ''8''
12''
1 2 ''12''
1 8 ''
6''12''8''12'
'
4''6''AVI
ARA P
Y COLLEGE BLC059
C050
C053
C075
C052
C074
C057
C080
C079
C083
C023
C065
C161
C144
C002
C145
C020
C137
C143
C017
I-
5AT & SF RRCANNON DR
PASEO DEL NORTE DRARMADA DRPALOMAR AIRPORT DRFLEET STL
E
GOL
A
N
D
SURFSI
DERUSSELIAMONTIAAgua Hedionda
Lagoon
Pacific Ocean
OVERWI
E DRP
A
S
E
O D
E
L N
O
R
T
E D
R
1 8 ''12''
6''8''24''
12''12''8''12''6''
12''12''
6''12''12''12''12''12''6''8''8''2 4 ''8 ''12''8''8''6''24''1 2 ''12''8''12''12''12''6''6''12''
1 2 ''12''
Legend
Recycled Water Pipelines (by Diameter)
Less than 6"
6" to 8"
10" to 14"
16" and larger
Potential Recycled Water Customers
Agriculture Irrigation
Landscape Irrigation
Commercial or Industrial Process Water
Other
Water System Facilities
Pump Station
WRF
Tank
Other
Parcels
Carlsbad City Limits
Water Body
0 1,000 2,000
Feet
Figure 3.10Potential Customers Near Avenida Encinas
Recycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_3_10-Potential_Customers_along_Avenida_Encinas.mxdDATE: 12/20/2010
Twin "D" Tanks
Bressi PS
"D" Tank PS
(Aggregate)
(Aggregate)
CAMINO VIDA ROBLE
P
AL
OMA
R OA
KSC093
C100C091
C076
C061
C084
C086C071
C085
C073
C092
C089
C054
C049
C066
C082
C081
C069
C058
C039
C096
C094
C099
C110
C064
C159
C160
C116
C032
18''2 4 ''4''20'
'
1
0''
12''4''
18''
4 ''12''4''12''4''18''8''10''18''18''8''4''8''8''8''8''8 ''1
2''
8''8''6''
30''
8''20''8''8''12''12''
1
8''
8 ''12''4''
4''
8''
8''
1
2''20''4''8''12''12''4''18''
8''
12''12''8''
12''8''1 0 ''8''4''20''18''
24''
1 2 ''20''12''18''4''4''8''8''8''8''1 2 ''
10''
18''
1
6''4''
27''6''8 ''4''18''8"E
L C
A
MIN
O R
E
A
L
PALOMAR AIRPORT RD
POINSETTIA LN
C O LLEGE BLPOINSETTIA LN
Legend
Recycled Water Pipelines (by Diameter)
Less than 6"
6" to 8"
10" to 14"
16" and larger
Potential Recycled Water Customers
Agriculture Irrigation
Landscape Irrigation
Commercial or Industrial Process Water
Other
Water System Facilities
Pump Station
Tank
Other
Near Term Customers (ongoing)
Parcels
Carlsbad City Limits
0 1,000 2,000
Feet
Figure 3.11Potential Customers
Near Palomar AirportRecycled Water Master Plan
Carlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_3_09-Potential_Customers_Near_Palomar_Airport.mxdDATE: 4/15/2011
January 2012 3-21 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
CMWD discussions with potential agricultural recycled water customers have indicated that
the potential for recycled water usage may depend on the specific water quality
requirements of each crop. It will also depend on the cost of the recycled water, and costs
associated with developing a system suitable for irrigating the crops use. For 2010, the
potable water demand for agriculture was 420 afy, which has steadily been declining since
1990.
The only existing agriculture customer using recycled water is the Flower Fields. Due to the
cost of the recycled water, converting the remaining interim agriculture use is probably not
cost effective and will not be counted on as potential customers in this study.
Commercial or Industrial Process Water
Industrial customers are sometimes the predominant application of recycled water in certain
cities with large areas of commercial and industrial land use types. CMWD has some
industrial water use at golf club manufacturing facilities, which currently use potable water.
To convert these manufacturing facilities over to recycled water use, CMWD would need to
interview the customer to determine their specific water quality needs to determine if
recycled water is suitable. Many industrial or commercial processes already use pre-
treatment systems for their process water; so in many cases, recycled water may be
acceptable. In general, recycled water may be used in a commercial or industrial process if
the recycled water is fully contained within the commercial or industrial process and the
general public does not come in direct contact with the recycled water.
Only one potential industrial customer, NRG West Coast LLC, is included in the customer
database. NRG West Coast LLC is considering expansion of its power plant. The power
plant has expressed interest in using recycled water for industrial process water as well as
landscape irrigation. NRG West Coast LLC provided estimates for water usage as well as
daily peaking factors. Advanced treatment for the process water would be done on-site.
Usage of recycled water for cooling or air conditioning applications has not been used
within CMWD’s existing recycled water customer base, but could be a source of additional
recycled water demands. Depending on the specific cooling system, advanced treatment
may be necessary for cooling water applications to avoid corrosion and scaling within the
cooling system. The customer database includes one specific customer that is currently
interested in recycled water for cooling applications for a commercial office building (C013).
It is anticipated that additional cooling towers for commercial office buildings will be
converted to recycled water in the future. In order to estimate the potential recycled water
demand associated with conversion of commercial office building cooling towers, CMWD
staff conducted a field investigation to determine the number of commercial office buildings
with cooling towers and the total potable demand associated with these customers. These
demands were grouped together for each of three large office parks in CMWD.
3-22 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Based on a study conducted by the San Francisco Public Utilities Commission (SFPUC), a
factor of 34 percent was applied to the total potable demand to approximate the component
associated with HVAC equipment within office buildings. When using recycled water to
replace potable water in cooling towers, the water use typically increases due to the
increased TDS in recycled water. This is known as reduced concentrations or cycles. It was
assumed that the increase in recycled water would be approximately 50 percent.
The resulting demands for each office park were reduced by 50 percent in order to account
for customers that would be considered too small or impractical to serve. These demands
are included in potential customers C110, C116, and C119.
Landscape Irrigation
HOAs, golf courses, resort properties, parks, schools, and other landscape irrigation are
typically the most common customers in a recycled water system. These customers and
their locations typically drive the layout of recycled water systems, and can be converted
easily to recycled water use if separate plumbing for the irrigation lines exists (e.g., if
potable water to restrooms and water fountains is fed by the same on-site pipelines as the
sprinklers, a retrofit is much more difficult).
It should be noted that properties developed after 1991 were subject to CMWD’s mandatory
use ordinance (CMWD, 2005b) and were required to design irrigation systems for eventual
recycled water connection, whether or not recycled water was available to the site.
The specific layout of certain HOAs limits the potential for recycled water conversion from
potable irrigation systems, due to the separation requirements for irrigation. Discussions
with CMWD staff highlighted specific HOAs for which conversion was anticipated to be
impractical.
Parks are another preferred customer, as their large demand typically consists almost
entirely of irrigation demands. These users can also be converted easily to recycled water
use as long as irrigation lines are separated from other facilities at the park, such as
restrooms.
School property often includes large fields, which are good candidates for conversion to
recycled water. When the irrigation lines are separated from the school potable systems,
these users can be converted easily to recycled water use.
Another type of landscape irrigation is commercial property irrigation. This usage type
includes the irrigation of small business parks, apartment landscaping, and the landscaping
surrounding commercial establishments. Typically, the demands for this use are small when
compared to larger recycled water users such as parks and schools. However, CMWD has
converted a large number of commercial irrigation users to recycled water by focusing
efforts in business park areas.
January 2012 3-23 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Other
CMWD has identified one mobile home park with a set of ornamental lakes that is
interested in recycled water to maintain the lake level (as the lake level declines due to
evaporation). This demand is classified as Pond Evaporation.
Demands for this customer were categorized with the existing system Public Works (used
for City utilities and the maintenance yard according to the 1997 RWMP [Carollo, 1997])
and Construction category as the category “Other”. Although the Construction category is a
temporary recycled water classification, it is assumed that future recycled water usage of
this category will be consistent with 2010 usage to account for usage of future construction
activities.
Neighboring Agencies
CMWD could potentially serve recycled water to customers of neighboring agencies located
just outside CMWD’s service area. These neighboring agencies are:
• Olivenhain Municipal Water District (OMWD)
• Vista Irrigation District (VID)
• Vallecitos Water District (VWD)
• City of Oceanside
OMWD has expressed interest in purchasing recycled water from CMWD at the southern
border of CMWD’s service area. Demand for this agency in the customer database is based
on preliminary estimates discussed with OMWD staff to serve both OMWD’s existing
demands and future demands within OMWD’s service area. It is anticipated that OMWD will
provide storage for daily peaking within their distribution system at Wanket Reservoir, and
be able to take water at a constant flow rate throughout the day. The Wanket Reservoir is
currently a part of OMWD’s potable water system, but is being investigated for potential
conversion to recycled water. The Wanket Reservoir is 3 MG in capacity, about 30 feet
high, and has a high water line (HWL) elevation of 427 ft-msl. As discussed in Chapter 4,
OMWD currently supplies its system from the Meadowlark WRF. Based on Alternative 2A
of the Northwest Quadrant Recycled Water Study (Boyle, 2004), the demand of OMWD’s
lower zones could be served from Gafner WRP. The study identified this based on supply
from Gafner WRP, but delivery from CMWD’s system could also apply. OMWD staff
indicated demand in the lower zones of OMWD is anticipated to be 500 afy (0.4 mgd), while
the anticipated growth in the upper zones is approximately 100 afy (0.1 mgd). The existing
and future demand of 500 afy for the lower zones is included as an individual demand in the
identified potential users; however, the 100 afy future demand for the upper zones is not
included, since it is anticipated that OMWD will supply these demands from Meadowlark
WRF.
3-24 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
VID’s service area is located to the east of CMWD’s service area, near Zones 580 and 660.
One of CMWD’s existing RW pipelines from Zone 660 crosses into VID’s service area,
which could potentially be used to connect new customers. The VID Water Reclamation
Master Plan (CDM, 1993) identified 109 potential customers within its service area. As
discussed in Chapter 4, the currently inactive Shadowridge Water Reclamation Facility is
located within VID’s service area and was originally intended to supply the Shadowridge
Golf Course with recycled water for irrigation. As the market assessment included in the
1993 Water Reclamation Master Plan was performed over a decade ago, the aerial
photograph and the City’s GIS layer of parks and schools were used to identify eight
potential customers, which were added to the customer database. One of these customer
database entries is an aggregate demand for a business park that represents
approximately 15 customers from the Water Reclamation Master Plan. CMWD obtained
potable water use records for customers within the VID boundary for verification of demand
projections.
VWD supplies CMWD and OMWD with recycled water, however, it does not retail recycled
water to customers within its service area. The 2002 VWD Water, Wastewater, and Water
Reclamation Master Plan Update (KJ, 2005) concluded that the demands from the potential
customers it identified were not sufficient to construct a distribution system to retail recycled
water, recommending instead to continue wholesaling the entire supply from Meadowlark
WRF to CMWD and OMWD. Using the aerial, as well as the schools and park GIS layer
provided by the City, six customers were added to the customer database within the VWD
service area. Two additional potential customers were added to the customer database
based on discussions with CMWD staff.
The City of Oceanside is located to the north of CMWD’s service area. The VID Water
Reclamation Master Plan identified an additional 26 customers located within the City of
Oceanside near the VID service area. Potential customers were also identified from the
City’s GIS layer of parks and schools, which extends into the City of Oceanside. The Ocean
Hills golf course was identified from the aerial photograph. A total of six potential customers
were added to the customer database. While the VID Water Reclamation Master Plan
mentioned that the City of Oceanside was considering producing recycled water at its San
Luis Rey Wastewater Reclamation Facility (SLRWRF), no master reclamation permits have
been issued by the regional water quality control board for the City of Oceanside at this
time. The SLRWRF maintains a small recycled water treatment facility. The reclamation
facility has a rated capacity of 0.7 mgd, but typically provides about 0.5 mgd to the
Oceanside Municipal Golf Course and nearby Whelan Lake. The City of Oceanside has
plans to construct a new reclamation facility at SLRWRF with a rated capacity of 1.5 mgd.
The additional recycled water will be used at the SLRWRF for plant water and irrigation
purposes. The new facility is master planned to allow phased expansion up to 7.5 mgd.
Implementation of additional phases will depend on customer demands and the cost of
potable water. Identified users for the SLRWRF recycled water are located in northern
Oceanside.
January 2012 3-25 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
3.5.3 Near Term Demands
CMWD is presently working on connecting additional customers to the existing recycled
water system. The locations of these “Near Term” customers were identified by CMWD staff
and include 25 retrofit sites for an estimated total demand of 50 afy and about 25 new
construction sites on remaining vacant industrial sites in Carlsbad Research Center, Bressi
Ranch, and Carlsbad Oaks North. The total of these customers is estimated to be an
additional 50 afy. This demand of 100 afy (0.1 mgd) was included as a “Near Term”
demand in addition to the identified potential and existing demands.
3.5.4 Summary of Potential Customers
Figure 3.9 shows locations for the potential customers identified in the customer database
and Table 3.6 summarizes the aggregate demands for these potential customers by
category and sub-category, while a detailed description of each potential customer is
included in Appendix C.
As shown in Table 3.6, the total additional potential future demand within CMWD’s service
area is approximately 2,711 afy (2.4 mgd). This demand includes 711 afy (0.6 mgd) for the
NRG power plant listed as C002 in Industrial in Table 3.6. The potential demand without the
NRG power plant would be 2,000 afy (1.8 mgd). In addition, 2,657 afy (2.4 mgd) of
demands were identified in the service areas of neighboring agencies for a total of
5,368 afy (4.8 mgd).
The demands identified in Table 3.6 include all potential users for which detailed
information is known, but does not include areas anticipated for eventual development not
associated with specific developments (which will be discussed later). This market
assessment is intended to determine all potential customers, while the determination of
whether a customer should be connected will be discussed in Chapter 9.
3-26 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Table 3.6 Customer Demand by Category
Recycled Water Master Plan
Carlsbad Municipal Water District
Customer Category(1)
Existing System
Demand(2)
(afy) Near Term
Demand
(afy)
Potential Future
Demand(3)
(afy) 2009 2010
Agricultural Irrigation 0 23 0 0
Commercial or Industrial Process
Water
0
Industrial 0 0 0 711
Commercial Cooling 0 0 0 62
Landscape Irrigation(4)
Commercial Property Irrigation 1,074 637 100 645
Community Facilities 27 49 0 0
Golf Courses 1,133 1,033 0 50
Highways 25 11 0 0
HOA 1,469 1,369 0 885
Resort Property Irrigation 340 195 0 75
Parks 195 69 0 147
Schools 85 91 0 131
Other 0
Construction 2 0 0 0
Pond Evaporation 0 0 0 5
Public Works 0 40 0 0
Subtotal inside Service Area 4,350 3,517 100 2,711
Neighboring Agencies(5)
Olivenhain Municipal Water District(4) 0 0 0 687
Vista Irrigation District 0 0 0 1,158
Vallecitos Water District 0 0 0 557
City of Oceanside 0 0 0 255
Subtotal outside Service Area 0 0 0 2,657
Total 4,350 3,517 100 5,368
Notes:
(1) Details by customer are presented in Appendix C.
(2) Average Existing Demand is shown for calendar years 2009 and 2010. An existing system demand of 4,000 afy is assumed for this study and will be used in later analysis of this chapter. However, demand for years 2009 and 2010 are shown here to show the demand by customer category.
(3) Potential Future Demand from Customer Database (see Appendix C and Table 3.7). Does not include demands for New Developments (areas which are anticipated to eventually develop but without definite
plans for development at this time).
(4) Landscape Irrigation is divided into 8 sub-categories. For the 500 afy OMWD demand, the breakdown of demands into sub-categories was not available, but the individual customers making up the 500 afy are anticipated to fall within the landscape irrigation category.
(5) Potential demand identified in neighboring agencies of City of Oceanside, OMWD, VID, and VWD.
January 2012 3-27 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
The demand estimates and usage type classifications of the 161 identified potential
customers are listed in Table 3.7, while their locations are presented on Figure 3.9,
Figure 3.10, and Figure 3.11.
Table 3.7 Potential Customers
Recycled Water Master Plan
Carlsbad Municipal Water District
Map ID(1) Customer Name AAD (afy) Customer Type
Included in Ultimate System(3)
C002 NRC West Coast LLC / Cabrillo
Power
711.0 Industrial Y
C004(2) KSL Resorts: La Costa Resort
(Group)
20.0 Resort Property
Irrigation
Y
C005 Robertson's Ranch - West Village (Phase 2) 118.3 HOA Y
C008(2) Rancho Carlsbad MHP 35.0 HOA Y
C009 Robertson's Ranch - East Village
(Phase 1)
65.8 HOA Y
C010 Tamarack Point HOA 42.0 HOA Y
C012 Rancho Carlsbad Golf Course
(Executive Course)
50.3 Golf Courses Y
C013 Invitrogen (Life Technologies) 18.0 Commercial Cooling Y
C014 San Pacifico HOA 41.5 HOA Y
C017(2) Alta Mira HOA 13.0 HOA Y
C018(2) Valley Middle School (Carlsbad Unified School) 17.0 Schools Y
C020 Carlsbad Property Inc (Group) 19.7 Commercial Property
Irrigation
Y
C021 Pan Pacific Retail Prop Inc 19.5 Commercial Property Irrigation Y
C023 William L Canepa 8.0 Resort Property
Irrigation
Y
C025(2) Army and Navy Academy
(includes Maxton Brown Park)
17.8 Schools Y
C026(2) Camino Hills HOA 17.8 HOA Y
C027 Full Range Prty LLC (Carlsbad
Golf Center)
17.5 Commercial Property
Irrigation
Y
C028(2) The Village Apartments 8.7 Commercial Property Irrigation Y
C029(2) Plaza Camino Real 25.6 Commercial Property
Irrigation
Y
C032 OVLC Management Co. DBA /
KSL (was Olympic Hotel / PAC)
15.0 Commercial Property
Irrigation
Y
3-28 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Table 3.7 Potential Customers
Recycled Water Master Plan
Carlsbad Municipal Water District
Map ID(1) Customer Name AAD (afy) Customer Type
Included in Ultimate System(3)
C033 Motel 6 - Site 000471 14.9 Commercial Property
Irrigation
Y
C034 City of Carlsbad Parks 14.9 Parks Y
C035 Senior Center Field (City of Carlsbad Parks) 3.4 Commercial Property Irrigation Y
C037(2) Hope Elementary School
(Group)
13.3 Schools Y
C038 Ponto Hotel 13.0 Resort Property Irrigation Y
C039 Palomar Triad #520 12.8 Commercial Property
Irrigation
Y
C040(2) Kelly Elementary School (Group) 10.5 Schools Y
C041(2) Carlsbad High School (Group) 10.1 Schools Y
C043 Brierly Field (City of Carlsbad Parks) 9.6 Parks Y
C044(2) Existing Landscape Meters near
Impala Dr and Palmer Wy
31.0 Commercial Property
Irrigation
Y
C045 Holiday Park (City of Carlsbad Parks) 9.3 Parks Y
C046 Holiday Park (City of Carlsbad
Parks)
8.5 Parks Y
C047 Chase Field (City of Carlsbad
Parks)
8.3 Parks Y
C049 Equity Growth Invest 7.9 Commercial Property
Irrigation
Y
C050 Carlsbad Commercial Center 7.8 Commercial Property
Irrigation
Y
C051 City of Carlsbad Parks 7.3 Schools Y
C052 Carlsbad Point Corporation 7.0 Commercial Property
Irrigation
Y
C053 Gildred Development 6.8 Commercial Property
Irrigation
Y
C054 2052 CDN LLC 6.8 Commercial Property
Irrigation
Y
C055 North Pointe HOA 1.5 HOA Y
C056(2) Greenview HOA 6.4 HOA Y
C057 Cognac Pacific Corporate LLC 6.4 Commercial Property
Irrigation
Y
January 2012 3-29 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Table 3.7 Potential Customers
Recycled Water Master Plan
Carlsbad Municipal Water District
Map ID(1) Customer Name AAD (afy) Customer Type
Included in Ultimate System(3)
C058 H G Fenton 6.1 Commercial Property
Irrigation
Y
C059 Cognac Carlsbad Pac Centr LLC 6.1 Commercial Property Irrigation Y
C060(2) Buena Vista Elementary School
(Group)
2.0 Schools Y
C061 North Pointe HOA 6.0 HOA Y
C062 Viaggio HOA and Aviara Masters HOA 9.2 HOA Y
C063 City of Carlsbad Parks 5.7 Parks N
C064 Future Parcel - Carlsbad Airport
Center
1.8 Commercial Property
Irrigation
Y
C065 Windstar Carlsbad Office LLC / Floral Trade Center 5.5 Commercial Property Irrigation Y
C066 Public Storage Inc 5.3 Commercial Property
Irrigation
Y
C067(2) Magnolia Elementary School
(Carlsbad Unified School)
3.1 Schools Y
C068(2) Dolphin Beach Apartments 1.0 HOA Y
C069 Kilwa Manufacturing Inc 5.2 Commercial Property
Irrigation
Y
C070 Jefferson Elementary School Irrigation (City of Carlsbad Parks)
5.1 Schools Y
C071 Realty Associates Fund VII LP 5.1 Commercial Property
Irrigation
N
C072(2) Lakeshore Gardens MHP (Group) 5.0 Pond Evaporation Y
C073 Naturemaker Inc 5.0 Commercial Property
Irrigation
Y
C074 Inns of America Suites 5.0 Commercial Property Irrigation Y
C075 Cognac Carlsbad Pacifica LLC 5.0 Commercial Property
Irrigation
Y
C076 Future Parcel - Carlsbad Airport Center 2.6 Commercial Property Irrigation Y
C078 City of Carlsbad Parks 4.6 Parks Y
3-30 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Table 3.7 Potential Customers
Recycled Water Master Plan
Carlsbad Municipal Water District
Map ID(1) Customer Name AAD (afy) Customer Type
Included in Ultimate System(3)
C079 Palomar and Company 4.4 Commercial Property
Irrigation
Y
C080 Inns of America Suites 4.4 Commercial Property Irrigation Y
C081 Bond Ranch 4.3 Commercial Property
Irrigation
Y
C082 Boi Carlsbad Inc 4.2 Commercial Property
Irrigation
Y
C083 CBRE Carlsbad Commercial Ctr 4.2 Commercial Property
Irrigation
Y
C084 North Pointe Owners' Assoc 2.0 HOA Y
C085 Palomar Lot 10 BCA 4.0 Commercial Property
Irrigation
Y
C086 Realty Associates Fund VII LP 4.0 Commercial Property
Irrigation
Y
C087 Tramanto HOA 3.8 HOA Y
C089 Carlsbad Corporate Center 3.5 Commercial Property
Irrigation
Y
C090 Bressi Ranch Corp Ctr 3.4 HOA Y
C091 Spy Optic Inc 3.4 Commercial Property
Irrigation
Y
C092 Del Abeto Cntr #260 3.1 Commercial Property
Irrigation
Y
C093 Palomar 910 Assoc Ltd 2.6 Commercial Property
Irrigation
Y
C094 Guy Freeborn 2.5 Commercial Property
Irrigation
Y
C096 Micro-Probe Prop LLC 2.4 Commercial Property Irrigation Y
C099 CBRE - Josepho Family Trust 1.1 Commercial Property
Irrigation
Y
C100 Sierra Land Group Inc 0.9 Commercial Property Irrigation Y
C104 Hosp Grove Park 2.0 Parks Y
C107 Alga Norte Park (Future) 71.9 Parks Y
C109(2) Future High School Site 30.0 Schools Y
C110 Business Park Cooling Towers in
Carlsbad Airport Center
9.9 Commercial Cooling Y
January 2012 3-31 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Table 3.7 Potential Customers
Recycled Water Master Plan
Carlsbad Municipal Water District
Map ID(1) Customer Name AAD (afy) Customer Type
Included in Ultimate System(3)
C116 Business Park Cooling Towers in
Carlsbad Research Center
30.0 Commercial Cooling Y
C119 Business Park Cooling Towers in Carlsbad Oaks 4.4 Commercial Cooling Y
C126 High-Density Residential
Development at Quarry Creek
64.5 HOA Y
C132 Rotary Park 2.2 Parks Y
C135 Magee Park 4.6 Parks Y
C137 Discovery Isle Child Development 3.6 Schools Y
C140 Irrigation Meters in Palisades
and Telescope HOA
11.7 HOA Y
C141 Beythlechim 0.6 Schools N
C143 Legoland Inner Park Expansion 33.6 Resort Property Irrigation Y
C144 Gemological Institute of America
Expansion
5.2 Commercial Property
Irrigation
Y
C145 Carlsbad Ranch Resort 37.9 Commercial Property Irrigation Y
C146(2) Dos Colinas (Senior Independent
and Assisted Care Living)
59.7 HOA Y
C147 Walmart / Sunny Creek Plaza 12.0 Commercial Property
Irrigation
Y
C148 Cantarini 115.0 HOA Y
C149 Holly Springs 93.1 HOA Y
C150 Carlsbad Oaks North - Phase I 42.1 Commercial Property
Irrigation
Y
C151 Carlsbad Oaks North - Phase II 34.0 Commercial Property Irrigation Y
C152 Carlsbad Oaks North - Phase III 36.3 Commercial Property
Irrigation
Y
C153 Bressi Ranch - Planning Areas 1
through 4
43.5 Commercial Property
Irrigation
Y
C154 Bressi Ranch - Planning Area 5 9.9 Commercial Property
Irrigation
Y
C155 Bressi Ranch - Planning Area 15 10.4 Commercial Property
Irrigation
Y
3-32 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Table 3.7 Potential Customers
Recycled Water Master Plan
Carlsbad Municipal Water District
Map ID(1) Customer Name AAD (afy) Customer Type
Included in Ultimate System(3)
C156 Rancho Carrillo Village H -
Palomar Korean Church
2.4 Commercial Property
Irrigation
Y
C157 Carlsbad Raceway and Palomar Forum - Remaining Vacant
Parcels
44.6 Commercial Property Irrigation Y
C158 HOA 11.1 HOA Y
C159 Existing Landscape Meters along
Palomar Oaks Way
15.7 Commercial Property
Irrigation
Y
C160 Future Business Park Irrigation
along Palomar Oaks
8.0 Commercial Property
Irrigation
Y
C161 Existing Landscape Meters along
Car Country Drive
12.0 Commercial Property
Irrigation
Y
C162 Existing Landscape Meters along Frost Avenue 8.0 HOA Y
C163 Existing Colony at Calavera
Irrigation Meters
7.2 HOA Y
C164 Existing Landscape Meters along El Camino Real 2.0 HOA Y
C165 Existing Landscape Meters at
Marbella (Apartment Complex)
2.0 HOA Y
C166 Existing Landscape Meters at Marea 8.6 HOA Y
C167 Existing Landscape Meters along
Blue Orchid Lane
9.7 HOA Y
C168 Existing Landscape Meters at Alga Hills HOA 17.2 HOA Y
C169 Existing Landscape Meters at
Jockey Club HOA
15.8 HOA Y
C170 Existing Landscape Meters along
Altisma Way
4.0 HOA Y
C171 Existing Landscape Meters at
Alicante Hills HOA
14.4 HOA Y
C172 Existing Landscape Meters along
Navigator Circle
3.4 HOA Y
C173 Library and Civic Center (City of Carlsbad Library and Parks) 5.0 Parks Y
C174 Existing Landscape Meters at
HOAs on Chinquapin Ave
24.0 HOA Y
January 2012 3-33 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Table 3.7 Potential Customers
Recycled Water Master Plan
Carlsbad Municipal Water District
Map ID(1) Customer Name AAD (afy) Customer Type
Included in Ultimate System(3)
C175 Existing Landscape Meters along
Oak Avenue
3.5 Commercial Property
Irrigation
Y
C176 Carlsbad Village Academy 11.0 Schools Y
C177 Existing Landscape Meter at Avenida Encinas 14.9 Commercial Property Irrigation Y
C178 Existing Landscape Meters at
The Villa HOA
20.0 HOA Y
C179 Existing Landscape Meters at Fairways HOA 26.8 HOA Y
Subtotal - Inside CMWD Service Area 2,711.0
C001 OMWD Customers (Gafner WRP or from Carlsbad WRF via El
Camino)
500.0 Landscape Irrigation Y
C108 La Costa Canyon High 63.9 Schools N
C118 Future School 31.4 Schools N
C120 La Costa Canyon Park 27.5 Parks N
C122 La Costa Heights Elementary/Levante Park 20.8 Parks N
C127 El Camino Creek Elementary 11.4 Schools N
C128 Olivenhain Pioneer Elementary 11.4 Schools N
C130 Mission Estancia Elementary 10.1 Schools N
C131 Cadencia Park 9.7 Parks N
C142 La Costa Valley Preschool and Kindergarten 0.5 Schools N
Subtotal - OMWD 686.7
C003 Shadowridge Golf Course 448.1 Golf Courses Y
C101 Business Park (Vista Irrigation District) 582.3 Commercial Property Irrigation Y
C111 Buena Vista Park 53.5 Parks Y
C114 Rancho Buena Vista High 39.2 Schools Y
C125 Center for
Science/Math/Technology
12.3 Schools N
C129 Breeze Hill Park 10.9 Parks Y
C134 Breeze Hill Elementary 7.9 Schools Y
C136 Tri City Christian Schools 3.7 Schools N
Subtotal - VID 1,157.9
3-34 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 3
Table 3.7 Potential Customers
Recycled Water Master Plan
Carlsbad Municipal Water District
Map ID(1) Customer Name AAD (afy) Customer Type
Included in Ultimate System(3)
C042 La Costa Meadows Elementary
School
9.7 Schools Y
C088 St. Elizabeth Seton Church 1.8 Schools Y
C102 Lake San Marcos Resort Country Club 336.0 Golf Courses N
C105 Lake San Marcos Executive Golf
Course
99.9 Golf Courses N
C112 Business Park (Vallecitos Water District) 42.7 Commercial Property Irrigation Y
C113 Park 39.7 Parks Y
C123 San Marcos High School 19.2 Schools N
C133 Fuerte Park 8.2 Parks Y
Subtotal - VWD 557.2
C103 Ocean Hills Country Club 148.0 Golf Courses Y
C115 Oak Riparian Park 36.5 Parks N
C117 Madison Middle/Lake Elementary 33.6 Schools Y
C121 Lake Park 22.4 Parks Y
C124 New Venture Christian Schools 13.4 Schools Y
C139 Montessori of Oceanside 0.9 Schools Y
Subtotal - City of Oceanside 254.8
Subtotal - Outside CMWD Service Area 2,656.6
Grand Total 5,367.6
Notes:
(1) Map IDs correlate to the site number in Figure 3.9.
(2) Cross-connection testing requirements may prevent full conversion of this site to recycled water.
(3) Indicates whether customer was determined to be feasible for connection to the potential expansion
segments as discussed in Chapter 9.
The distribution of demands relative to service area is shown on Figure 3.12. This figure
illustrates that about 50 percent of the potential future demand is located within CMWD’s
service area while the remaining 50 percent is distributed within neighboring agencies.
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Inside CMWD Service Area
2,711 afy
50%
OMWD
687 afy
13%
VID
1,158 afy
22%
VWD
557 afy
10%
Oceanside
255 afy
5%
Figure 3.12 Distribution of Potential Demands by Service Area
3.5.5 Customer Questionnaire
Customer surveys were developed and sent to several of the largest potential customers
identified in the customer workshop. These questionnaires requested information about any
barriers the customers had to using recycled water.
The majority of the mailed customer questionnaires did not successfully reach the potential
customers due to a discrepancy between the service address and billing addresses.
However, in general, results of the survey showed that customers were interested in
recycled water. Several customers mentioned that financing of recycled water conversion
would be the primary barrier to adopting recycled water. To date, CMWD has not assisted
in financing of customer site conversions, and has no plans for participating in financing of
conversions in the future. Overall, the responses that were received did not indicate hostility
toward the usage of recycled water.
3.5.6 Smaller Pickup Customers
Identifying potential customers beyond the 161 potential users included in the customer
database is not anticipated to be viable. An additional 144 customers were identified with
historical potable water billing records totaling approximately 55 afy (less than 0.1 mgd).
However, the demand of these additional 144 customers is relatively low demand when
compared to the top 161 potential customers listed in the customer database. The steep
decline in demand by customer is also illustrated on Figure 3.13.
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Figure 3.13 Large User Demand Ranking Effect
As shown in Figure 3.13, the demand of each individual potential customer drops off
significantly after the first few large customers. Because of this drop off effect, recycled
water demands for the 144 potential customers ranking past the top 161 were not included
in this study. CMWD has worked extensively to identify potential customers for conversion
near the existing system and it is assumed this effort will continue in the future.
3.5.7 Demand Factors
For new developments or customers without historical billing records, demand factors were
developed to estimate potential demand based on historical demand records and areas of
known developments.
Demand factors were developed for irrigation associated with HOAs, commercial and
industrial properties, golf courses, schools, and parks. Demand factors were not developed
for other uses since City planning documents did not indicate other large planned
developments with other uses. It is assumed that future development of planned
communities (with HOA demands) and business parks (commercial and industrial irrigation)
will be similar in irrigation practices to recent developments. Some areas of typical recent
development were selected for each of these categories to develop the recycled water
demand factors. These water demand factors are presented in Table 3.8.
10
20
30
40
50
60
70
80
Average Annual Demand (afy)
Recycled Water User Ranking
1 161 81
Cabrillo Power 711 afy
OMWD
500 afy
Shadowridge
Golf Course (VID) 448 afy
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Table 3.8 Water Demand Factors
Recycled Water Master Plan
Carlsbad Municipal Water District
Usage Type Description Water Demand Factor (gpd/ac)
HOAs Includes irrigation of street medians and
common areas of HOAs
700
Business Park Landscape irrigation for commercial and
industrial properties
600
School Irrigation of fields and landscaping of schools 1,000
Park Irrigation of parks 2,000
Golf Course Irrigation for golf courses 2,500
Note:
(1) Water Demand Factors are applied to the parcel acreage, and thus exclude streets.
It should be noted that recycled water use within HOAs is primarily within common areas
and street medians. While residential planned communities can use recycled water for
irrigation of individual homes, the cross-connection testing requirements render irrigation of
individual homes with recycled water infeasible.
It should also be noted that the typical commercial and industrial properties and business
parks consists of very little irrigated area. Based on aerial imagery, typical lots may consist
of about 10 percent irrigated landscaping. It is assumed that future commercial property
development will use irrigation in a similar manner as existing commercial properties.
3.5.8 New Developments
New developments present a unique opportunity for recycled water use, as the location and
installation of recycled water distribution infrastructure can be implemented during initial
construction of the development, resulting in shorter construction time and lower cost
compared to construction in existing developments where pavement repair and traffic
control would be required.
The City’s Planning Department provided a list of parcels with anticipated development.
This list was joined to the City’s GIS parcel layer. Subsequently, the Planning Department’s
classifications were adapted to recycled water usage designations as follows:
• Residential parcels (Multiple Family [MF], Single Family [SF], and Septic) were
assigned to the HOA category if the parcels fell within tracts of land suitable for
planned community development. Isolated individual residential parcels less than
5 acres in size were not considered suitable for recycled water irrigation.
• Commercial and Industrial parcels were assigned to the Commercial and Industrial
Property Irrigation category.
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The data provided by the planning department focused on detailed development over the
next five years, but in most cases, development past five years was assumed to increase
linearly across the years within the planning period.
Where information on detailed development was available, the relevant parcels were added
to the customer database. These parcels are shown in brown on Figure 3.14. The
remaining development areas were categorized into either Residential (consisting of HOA
type development) or Commercial Irrigation (consisting primarily of commercial and
business park irrigation) and the corresponding demand factors were applied to estimate a
total future demand due to development. Since CMWD has focused its conversion efforts
on developments that are able to adequately take advantage of recycled water, it is
anticipated that not every development can fully utilize recycled water to the same extent.
Thus, the total future demand due to new developments was reduced by 50 percent.
The areas are shown in Figure 3.14 and the demand is summarized in Table 3.9.
Table 3.9 New Development Demand Projections Recycled Water Master Plan
Carlsbad Municipal Water District
Land Use Type Total Acreage (Parcels >5 ac)
Demand
Factor (gpd/ac)
Total Future
Demand (gpd)
Total Future
Demand (afy)
Residential 615 700 430,500 482
Commercial Irrigation 306 600 183,600 206
Subtotal 921 N/A 614,100 688
50% Reduction N/A N/A -307,050 -344
Total
307,050 344
"C" Tank
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoon
Twin "D" TanksCamino Re
al
E lm A v e
Marron Rd
C
arls
b
a
d Blv
d
H
i
g
h
la
n
d Dr
A lo n d ra W a y
Paseo NorteC ollege B lvdPalomar Airport RD
Aviara Pkwy El Fuerte StCosta Ave
P o in s e ttia L n
T a m a r a c k A v e
Cannon Rd
Calle Barcelona
R ancho Santa Fe
Calavera PS
Bressi PS
"D" Tank PSPacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
Lake
Calavera
San Marcos
Vista
Encinitas
Oceanside Legend
Recycled Water Pipelines (by Diameter)
Less than 6"
6" to 8"
10" to 14"
16" and larger
Recycled Water Facilities
Pump Station
Pressure Regulation Station (PRS)
WRF
Tank
Reservoir
Inactive WRP
New Developments
Residential
Commercial Irrigation
Development not anticipated toutilize Recycled Water (Small Parcels)
Represented in Customer Database
Others
Freeways
Major Roads
Local Streets
City Boundary
Carlsbad City Limits
San Diego County
Water Body
Carlsbad Municipal Water District
0 5,000 10,000
Feet
Figure 3.14Areas of New Developments
Recycled Water Master Plan
Carlsbad Municipal Water District
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_3_13-Incorporating Recycled Water.mxdDATE: 4/15/2011
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3.5.9 Demand Summary
The total potential demand for the ultimate system is projected by combining the existing
demand, the near-term demand, the demand from the potential customer database (inside
and outside CMWD’s service area), and the demand from new developments. Table 3.10
presents a summary of demand projections while Figure 3.15 graphically shows the build
out demand by customer category.
Table 3.10 Summary of Demand Projections
Recycled Water Master Plan Carlsbad Municipal Water District
Customer Category Demand (afy) Source
Existing 4,000 End of Section 3.3.2
Near-Term 100 Table 3.6
Customer Database
(in Service Area) 2,711 Table 3.6
Neighboring Agencies 2,657 Table 3.6
New Developments 344 Table 3.9
Potential Total Demand 9,812
New Developments(Potential Areas of DevelopmentNot Accounted for in
Customer Database)344 afy
Existing Customers
4,000 afy
Potential Demand in NeighboringAgencies2,657 afy
Potential Demand inside Service Area
(Customer Database)2,711 afy
Near Term Customers100 afy
Figure 3.15 Potential Build Out Demand Summary
Total Potential Demand 9,812 afy
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As shown in Table 3.10, the potential build out demand is estimated to be approximately
9,812 afy (8.3 mgd).
The feasibility of serving this potential build out demand is evaluated in Chapter 9, Future
System Analysis, which includes an analysis of the various pipeline alignments required to
serve this total potential demand. The results of this analysis are used to prioritize pipeline
extension projects and determine the build out demand that is considered for the Capital
Improvement Program (CIP) projects presented in Chapter 10 of this master plan.
A summary of customers by location in relation to the service area is presented in
Table 3.11.
Table 3.11 Potential Build Out by Service Area Recycled Water Master Plan
Carlsbad Municipal Water District
Category
Demand Inside
Service Area
(afy)
Demand Outside
Service Area
(afy)
Total
Demand
(afy)
Existing 4,000 0 4,000
Near Term / In Progress 100 0 0
Potential Future Demand(1) 2,711 2,657 5,368
New Developments(2) 344 0 344
Total 7,155 2,657 9,812
Percentage 73% 27% 100%
Note:
(1) Customers identified within the customer database (Appendix C). Customers with a Purveyor of OMWD, VID, VWD, or Oceanside are outside CMWD’s service area.
(2) Additional development not individually identified which did not have specific information on timing. Included to adequately size pipelines for ultimate build out conditions.
As shown in Table 3.11, the potential build out demand includes approximately 2,657 afy or
27 percent of recycled water demand from customers that are located outside CMWD’s
service area.
CMWD should consider adopting a goal for maximizing the cost effective use of recycled
water within its service area. Currently, recycled water use accounts for almost 20 percent of
the aggregate water within CMWD. As shown in Table 3.12, if all potential demands within
CMWD are connected, CMWD will meet a recycled water use goal of approximately
27 percent by the year 2020. The demand projections for the year 2020 are based upon a
2020 potable water demand of 25,100 afy from CMWD’s 2010 Urban Water Management
Plan (UWMP). It should be noted that the development assumptions in the UWMP may not
have assumed the same development shown in Figure 3.14.
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Table 3.12 Percentage of CMWD Demand Identified
Recycled Water Master Plan Carlsbad Municipal Water District
Potable Demand Projection Year
2020(1)
(afy)
Potential
RW Demand(2)
(afy)
Total Demand
Year 2020
(afy)
Maximum Percentage
Recycled Water
by Year 2020(3)
25,100 6,811 31,911 27%
Notes:
(1) Source: CMWD’s 2010 UWMP (CMWD, 2010).
(2) Demand Inside Service Area based on demands from Table 3.11, deducting New Developments as not likely to be in place by 2020.
(3) If all Potential RW Demands except New Developments were realized by 2020.
Chapter 9 discusses the specific customers that could be connected to expansion
segments of the future recycled water system, and which potential customers were not able
to be connected to expansion segments in a cost-effective manner. Table 3.13 presents a
summary of the demands included in the ultimate recycled water system based on the
discussion in Chapter 9. As shown, the build-out system includes a total of 7,144 afy
(6.4 mgd) considering only the demand within CMWD’s service area and, totaling 9,106 afy
(8.1 mgd) including demands from neighboring agencies.
Table 3.13 Build-out Demand Summary
Recycled Water Master Plan Update Carlsbad Municipal Water District
Demand Description AAD (afy) AAD (mgd) MMD (mgd)
Existing + Near-Term (Phases I and II) 4,100 3.7 6.2
Potential Customers within CMWD 2,711 2.4 4.1
New Developments (with indefinite timing) 344 0.3 0.5
Total Identified Demand within CMWD 7,155 6.4 10.9
Not Feasible inside Service Area -11 < 0.1 < 0.1
Total for CMWD Build-out System 7,144 6.4 10.8
Potential Customers outside CMWD 2,657 2.4 3.7
Not Feasible outside Service Area -695 -0.6 -1.1
Total for Build-out System with Neighboring Agencies 9,106 8.1 13.5
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Chapter 4
RECYCLED WATER SUPPLIES
4.1 INTRODUCTION
This chapter identifies the Carlsbad Municipal Water District’s (CMWD) supply and related
storage needs required to meet the projected water demands identified in Chapter 3. This
chapter starts with a description of the existing and future recycled water supply sources.
Subsequently, the capacity of these sources are compared with the projected recycled
water demands to determine any supply shortfalls. As part of the supply evaluation, six
supply scenarios are evaluated based on various combinations of expanding supply
sources. This chapter is concluded with a supply strategy that describes the phasing of
supply projects to accommodate the recommended system configuration described in
Chapter 9 of this recycled water master plan (RWMP).
4.2 SUPPLY SOURCES
This section discusses each of CMWD’s existing recycled water supply sources and their
associated capacities as well as the historical utilization of each supply source.
4.2.1 Existing Supply Sources
As discussed in Chapter 3, CMWD receives recycled water from three reclamation plants:
Carlsbad Water Recycling Facility (WRF), Meadowlark WRF, and Gafner Water
Reclamation Plant (WRP).
The Carlsbad WRF is owned by CMWD; and the Encina Wastewater Authority (EWA) has
been contracted to provide operation and maintenance through a memorandum of
understanding (MOU) dated May 1, 2005.
The Meadowlark WRF is owned and operated by the Vallecitos Water District and serves
both CMWD’s recycled water system and a portion of the Olivenhain Municipal Water
District’s (OMWD) recycled water system within the City of Carlsbad.
The Gafner WRP is owned and operated by the Leucadia Wastewater District and serves
only the south golf course of the La Costa Resort. The Gafner WRP does not connect to the
rest of CMWD’s recycled water distribution system.
Carlsbad WRF and Gafner WRP currently operate as tertiary treatment plants, treating
secondary effluent from the Encina Water Pollution Control Facility (EWPCF). Meadowlark
WRF operates as a “skimming” plant, discharging solids into a 10-inch diameter sludge
pipeline for treatment at the EWPCF. The capacities of the Carlsbad WRF, Meadowlark
WRF, and Gafner WRP are presented in Table 4.1 along with CMWD’s recycled water
allocation.
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Table 4.1 Recycled Water Supplies
Recycled Water Master Plan
Carlsbad Municipal Water District
Reclamation
Plant Name Owner
Permitted Capacity(1)
(mgd)
Maximum CMWD Allocation
(mgd)
Other Allocations
(mgd)
CWRF CMWD 4.0 4.00 0.0
MWRF VWD 5.0 3.00(2) 1.5(3)
GWRP LWWD 1.0 0.75(4) 0.0
Total Capacity 10.0 7.75 1.5
Total Usable Capacity(5) 7.60(5)
Notes:
VWD = Vallecitos Water District; LWWD = Leucadia Wastewater District
(1) Maximum discharge flow as stated in permit (CWRF Order No. 2001-0352; MWRF Order No. R9-2007-0018; GWRP Order No. R9-2004-0223, included in Appendix E).
(2) Rated capacity of MWRF is 5.0 mgd. However, discussions with VWD staff have indicated that the WRF historically has produced less flow than rated. While the rated capacity is 5.0 mgd, the actual produced
flow is less (3.2 mgd in 2009) due to insufficient wastewater flow to Meadowlark. CMWD’s agreement with VWD limits supply availability to 3.0 mgd during summer months and 2.0 mgd during winter months.
(3) Current MWRF allocation for the Olivenhain Municipal Water District is 1.0 mgd with an option to
purchase up to 1.5 mgd.
(4) Based on the agreement between LWWD and CMWD (included in Appendix D) that states that the GWRP can produce up to 0.75 mgd, a maximum and minimum annual purchase of 840 afy (0.75 mgd)
and 394 afy (0.35 mgd), respectively.
(5) As the GWRP is not connected to CMWD’s recycled water system and the demand of the La Costa Resort and Spa south golf course MMD is only 0.6 mgd (versus 0.75 mgd capacity at GWRP), the total
existing usable capacity is limited to 7.6 mgd.
As shown in Table 4.1, CMWD currently has 7.75 mgd of allocated supply capacity,
although only 7 mgd is available to CMWD’s primary recycled water distribution system as
Gafner WRP only supplies the La Costa Resort and Spa south golf course and is not
connected to the rest of the distribution system. In total, the reclamation plants have a
permitted capacity of 10 mgd.
4.2.2 Historical Supply Utilization
While daily supply data for Meadowlark WRF and Carlsbad WRF was available (EJPA,
2009) for January 2005 through June 2009, the daily demands for the OMWD system were
not known for the same period, and thus could not be deducted to determine CMWD’s daily
utilization of supply sources. Monthly supply data for the portion of flow supplied to
CMWD’s distribution system by Meadowlark WRF, as well as total flow from Carlsbad
WRF, and Gafner WRP was available (CMWD, 2011) for the calendar year 2010 and is
presented in Table 4.2.
During periods of high recycled water demands or recycled water supply outages, CMWD
has had to supplement its recycled water system with potable water. Potable water can be
introduced to the recycled water distribution at CMWD’s D Tanks, through the use of an air
gap. The connection is made up of a meter and an 8-inch diameter Pressure Sustaining
January 2012 4-3 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4
Valve (PSV), which, according to CMWD staff, can convey at least 3,000 gpm. Potable
water can also be supplemented in the system feeding the La Costa Resort and Spa south
golf course from Gafner WRP. In addition, VWD has a potable water connection at Mahr
Reservoir, which can be used to supplement recycled water in the reservoir with potable
water through an air gap.
Table 4.2 Utilization of Recycled Water Supplies Recycled Water Master Plan
Carlsbad Municipal Water District
Source
Average Annual
Supply in 2010
Percentage of
Average Annual Supply in
2010
Maximum
Month Supply(2) in 2010
(mgd)
Percentage of
Maximum Month Supply in 2010
(mgd) (afy) (mgd)
CWRF 969 0.9 28% 2.2 38%
MWRF (1) 2,272 2.0 66% 2.9 50%
GWRP 195 0.2 5% 0.6 11%
Potable Water (3) 30 < 0.1 1% 0.1 1%
Total 3,466 3.1 100% 5.8 100%
Notes: (1) Portion of MWRF recycled water supplied to CMWD. MWRF also supplies recycled water to OMWD
customers. (2) The month of maximum demand in calendar year 2010 was 5.8 mgd in June 2010. Note that maximum month supply for individual sources varied by supply source (e.g., MWRF produced its maximum monthly flow in May 2010). (3) Potable makeup water use in 2010 included 4.8 afy at the D Tank supplemental water connection and 25.7 afy at Gafner WRP.
As shown in Table 4.2, in 2010, CMWD obtained the greatest percentage of its supply from
the Meadowlark WRF. Under typical operations, CMWD first obtains supply from the
Meadowlark WRF and uses the Carlsbad WRF to balance supply with demand because
CMWD pays for allocated supplies from Meadowlark WRF even if the supply is not used. In
accordance with the inter-agency agreement, CMWD purchases 2 mgd from December
through March (4 months) and 3 mgd from April through November (8 months). Note that in
2009, CMWD obtained the largest component of its supplies from Carlsbad WRF because
the Meadowlark WRF has at times not provided the contracted 3 mgd due to a lack of
influent flow that limited effluent recycled water production. Influent flow at the Meadowlark
WRF did not match expected flow projections from the time of the Meadowlark WRF
expansion because the housing downturn had slowed development, which would have
increased influent flow.
During the maximum month (June 2010) CMWD’s demand was 5.8 mgd. During this
month, CMWD still obtained the majority of its flow from Meadowlark WRF, with slightly
more supply coming from Carlsbad WRF. It should be noted that potable makeup water
was primarily supplemented at Gafner WRP when Gafner WRP was offline for several
months in 2010. Potable makeup water at the Twin D tanks was primarily used in
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June 2010 when demands were the highest of the year. Note that data for VWD’s potable
water makeup connection at Mahr Reservoir was not available and is not included in
Table 4.2.
During the minimum month (February 2010), CMWD’s demands were only 0.51 mgd,
significantly less than the 2.0 mgd allocation from Meadowlark WRF. CMWD supplied
demands during this month almost exclusively from Meadowlark WRF.
Daily flows from Carlsbad WRF and Meadowlark WRF were obtained from water quality
reports to the regional water quality control board (EJPA, 2009) for January 2005 through
June 2009. As discussed in Chapter 3, it was assumed that MDD will be similar to MMD
since CMWD’s customers are primarily irrigation in nature. While daily flow data was
analyzed to determine the actual MDD to MMD ratio, several limitations were found in the
daily flow data. Limitations precluding this calculation included daily effluent data for
Meadowlark WRF was reported for total plant flow including OMWD’s demands, daily flows
for potable makeup water were not reported, several daily flows from Carlsbad RWMP
significantly exceeded the rated capacity, daily storage in Mahr Reservoir was not reported.
Figure 4.1 presents the total annual historical supply for calendar years 2002 through 2010,
including potable makeup water. Note that data for 2004 was not available, and supply data
for 2009 was only available through June 2009 due to the fiscal year (supply data was
projected for the rest of the year). Average annual demand data from billing records is
overlaid on Figure 4.1 for the calendar years 2004 through 2010. As shown, the demand
reported in 2010 slightly exceeded reported supplies, likely due to rounding in monthly
reporting.
As shown in Figure 4.1, demand increased significantly between 2003 and 2005 as
Phase II customers began to be connected.
Figure 4.2 shows approximate historical supply for each supply source. Supplies for
Meadowlark WRF and Gafner WRP were taken from the annual reports for the Reclaimed
Water Development Fund (CMWD, 2011), while supply data for Carlsbad WRF were taken
from daily flow monitoring from monthly water quality monitoring reports obtained from
Encina Joint Powers Authority (EJPA, 2009). Since the annual reports for the Reclaimed
Water Development Fund are summarized by fiscal year, and reports specific to each
supply source for some consecutive years were not available, supply for the months
available was assumed to be representative of the full calendar year.
As shown in Figure 4.2, total recycled water supply to CMWD increased between 2006 and
2008 due to the addition of the Carlsbad WRF in 2006 and the completion of upgrades to
the Meadowlark WRF in 2008. Overall supplies decreased in 2010 in response to the
decreased demands discussed in Chapter 3.
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0
1,000
2,000
3,000
4,000
5,000
6,000
2002 2003 2004 2005 2006 2007 2008 2009 2010Average Annual Supply (afy)Calendar Year
Total Supply (from Monthly MWD Reports)
Total Demands (from Billing Data)
(1)
Notes:(1) As data for this calendaryear was incomplete, average flows for the months available were assumed to apply to the rest of the year.(2) Data was only available through June, the seasonal peaking for 2008 was applied to 2009 data available to project a 2009
supply.
(1)
(2)
(1)
(1)
(1)
n/a
Figure 4.1 Historical Supply
0
500
1,000
1,500
2,000
2,500
3,000
3,500
2002 2003 2004 2005 2006 2007 2008 2009 2010Average Annual Supply (afy)Calendar Year Gafner WRP (afy)
Meadowlark WRF (afy)
Carlsbad WRF (afy)
Notes:(1) As data for this calendar year was incomplete, average flows for the months available were assumed to apply to the rest of the year. (2) Seasonal peaking for 2008 was applied to monthly data through June 2009 to project supply. (It was assumed that Carlsbad WRF would provide projected supplies beyond the historic capacity of Meadowlark WRF.
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(2)
(2)
(2)
n/a
Figure 4.2 Historical Supply by Source
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4.2.3 Water Quality of Existing Supply Sources
Water quality from the existing sources was analyzed to determine any restrictions that may
exist for irrigation uses. Water quality data was tabulated and compared to existing
guidelines for irrigation use restrictions. This data is summarized in Table 4.3.
As shown in Table 4.3, the average historical water quality samples do not indicate any
severe restrictions for any of CMWD’s recycled water supply sources. As there are no
parameters that fall in the severe restriction category, CMWD should be able to use their
existing recycled water sources for its irrigation demands with proper quality management.
However, due to some water quality parameters, the use of recycled water may not be
suitable for some sensitive plant species. For instance, discussions between CMWD staff
and specific agricultural users have indicated concerns about water quality parameters
which may affect required treatment, including boron, manganese, and TDS.
Boron
One constituent of potential concern is boron. Currently, effluent from all three wastewater
reclamation plants contains a boron concentration of approximately 0.4 mg/L, as displayed
in Table 4.3. In the future, this effluent concentration could increase due to the construction
of the new Poseidon desalination facility in the City of Carlsbad (City).
The new desalination facility will use reverse osmosis treatment to desalt ocean water for
drinking water purposes. Typical ocean water has a boron concentration between 4 and
5 mg/L. According to correspondence with the City, the new plant’s effluent will have a
boron concentration of approximately 0.75 mg/L. Once this new supply is integrated with
Carlsbad’s existing potable water supply, the concentration of boron will increase. As a
result, the concentration of boron in wastewater will also increase.
While, the increased concentration will not impact the “Degree of Use Restriction” in
Table 4.3, the increased concentration in wastewater does have the potential of pushing
treated recycled water effluent above the limit for boron as stated in CMWD’s discharge
permit. Currently, the permit stipulates a boron concentration limit of 0.75 mg/L for the
Carlsbad WRF and 0.5 mg/L for the Meadowlark WRF.
It is recommended that CMWD coordinate with the new desalination plant to ensure that the
boron concentration from the desalination plant will not cause recycled water effluent to
exceed these permitted limits.
If the limit is exceeded, the only process capable of removing boron is reverse osmosis with
upstream pH adjustment. At neutral pH, boron exists as boric acid (H3BO3), which is neutral
and is a similar size to a molecule of water, allowing it to pass through RO membranes.
Boron can be removed by raising the pH above 9, so the boron is deprotonated, forming
dihydrogen borate (H2BO3-).
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Table 4.3 Water Quality Guidelines for Irrigation Use Recycled Water Master Plan Carlsbad Municipal Water District
Water Quality Parameter(1) Unit
Degree of Use Restriction(1,2,3,4) Supply Source
None Slight to Moderate Severe MWRF(7) CWRF(8) GWRP(9)
Salinity
ECw dS/m <0.7 0.7-3.0 >3.0 1.63 1.70 1.73
TDS mg/L <450 450-2000 >2000 991 965 1,076
Permeability(5) ECw = 0.9
SAR = 0-3 and ECw = >0.7 0.7-0.2 <0.2
SAR(6) = 3-6 and ECw = >1.2 1.2-0.3 <0.3 1.6 1.7 1.7
SAR = 6-12 and ECw = >1.9 1.9-0.5 <0.5
SAR = 12-20 and ECw = >2.9 2.9-1.3 <1.3
SAR = 20-40 and ECw = >5.0 5.0-2.9 <2.9
Sodium (Na)
Surface SAR <3 3-9 >9 4.0(6) 5.5(6) 5.6(6)
Sprinkler mg/L <70 >70 152 197 201
Chloride (Cl)
Surface mg/L <140 140-355 >355 236 265 278
Sprinkler mg/L <100 >100 236 265 278
Boron (B) mg/L <0.7 0.7-3.0 >3.0 0.37 0.40 0.41
Bicarbonate mg/L <90 90-500 >500 192 219 225
pH --- 6.5-8.4 (normal range) 6.7 7.4 7.3
Nitrogen (N)
Ammonia (NH4) mg/L (see combined N values below) N/A N/A N/A
Nitrate (NO3) mg/L (see combined N values below) N/A N/A N/A
Combined Nitrogen (N) mg/L <5 5-30 >30 N/A N/A 16.1
Iron Recommended maximum concentration of 5 mg/L. Not toxic to plants in aerated soils but can contribute to soil acidification and loss of reduced availability of essential phosphorus and molybdenum.
Manganese Recommended maximum concentration of 0.2 mg/L. Toxic to a number of crops at a few tenths to a few mg/L, but usually only in acid soils. Notes: (1) Adapted from University of California Committee of Consultants (1974), and Ayers and Westcot (1994). (2) Method and Timing of Irrigation: Assumes normal surface and sprinkler irrigation methods are used. Water is applied as needed, and the plants utilize a considerable portion of the available stored soil water (50% or more) before the next irrigation. At least 15 percent of the applied water percolates below the root zone (leaching fraction [LF] > 15%). (3) Site Conditions: Assumes soil texture ranges from sandy loam to clay with good internal drainage with no uncontrolled shallow water table present. (4) Bold text indicates where CMWD’s Supply Sources from the right columns fall within the range shown. Definitions of “The Degree of Use Restriction” terms: None = Recycled water can be used similar to the best available irrigation water. Slight = Some additional management will be required above that with the best available irrigation water in terms of leaching salts from the root zone and/or choice of plants. Moderate = Increased level of management required and choice of plants limited to those which are tolerant of the specific parameters. Severe = Typically cannot be used due to limitations imposed by the specific parameters. (5) Permeability is evaluated based on the combination of adjusted sodium adsorption ratio (SAR) and Electrical Conductivity (ECw) values. (6) Adjusted SAR (adj. RNa) includes the effect of bicarbonate/calcium ratio (Cax). (7) Average of Samples from January 1998 through September 2009. Source: (EJPA, 2009). (8) Average of Samples from November 2005 through September 2009. Source: (EJPA, 2009). (9) Average of Quarterly Samples from Oct 2008 through September 2009 (TDS, N, Conductivity, and pH), Annual samples in June 2008 (Cl, B), and intermittent samples from 2002 through 2009 (Na, HCO3). Source: (EJPA, 2009).
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For CMWD, removing boron would involve pH adjustment and installing a secondary RO
treatment train at the Carlsbad WRF. As this addition adds additional capital cost to any
plant expansion, it is recommended that CMWD control the concentration of boron at the
source of potable water production, the new desalination plant.
Manganese
Another constituent of concern is manganese since CMWD’s Carlsbad WRF exceeds the
permitted effluent limit of 0.05 mg/L when the Carlsbad WRF is operated as designed. The
Carlsbad WRF was designed for granular media filtration of 80 percent of the influent flow
and MF/RO filtration for the remaining 20 percent of the influent flow. The flow streams are
blended prior to distribution. As the Carlsbad WRF does not currently operate at capacity,
there is spare MF/RO capacity. To reduce the manganese concentration, the plant operates
beyond the 20/80 flow split, sending a greater percentage of flow to the MF/RO units.
While, the MF/RO process reduces manganese, this solution is not permanent since the
Carlsbad WRF will need to run at capacity in the future and will be restricted to the 20/80
flow split since spare MF/RO units will not be available.
Providing additional treatment for the removable of manganese will require improvements
to the Carlsbad WRF, which requires a substantial investment for both facility
improvements and operations. Removal of manganese typically involves the oxidation of
the water soluble manganese ions (Mn+2) with the addition of chlorine or potassium
permanganate in a contact tank and the removal of the resulting insoluble manganese
oxides through filtration. At the Carlsbad WRF, removal of manganese would involve a
contact chamber for the addition of chlorine or potassium permanganate and possibly a
new set of filters. The Carlsbad WRF could potentially use the existing granular media
filters, but the effectiveness of the existing filters would need to be verified. It should be
noted that the Carlsbad WRF also could replace the media of some existing filters with
media designed specifically for manganese removal. Filtronics, Inc. has a proprietary
media, FV03 Electromedia®, specially designed to remove manganese through magnetic
attraction. Alternatively, manganese can be removed through a greensand process. The
greensand process involves the use of filters with natural greensand zeolite that is coated
with manganese oxides. The oxides on the greensand remove the soluble manganese ions
until the oxides become saturated; at which point, the greensand oxides are regenerated
with potassium permanganate. This alternative method does not involve a contact chamber,
only greensand filters.
While manganese is an essential nutrient at low dosages, it is harmful to ingest at high
doses. The EPA has set a Secondary Maximum Contaminant Level (SMCL) for manganese
at 0.050 mg/L based on aesthetic concerns for drinking water such as staining and taste
considerations. Ingestion of manganese through water consumption is not considered
harmful unless the concentration is above 0.3 mg/L. The Regional Board most likely set the
0.05 mg/L limit in order to protect the underlying groundwater basins, which have
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manganese objectives of 0.05 mg/L. Manganese concentrations below 0.3 mg/L are not
known to have any negative health effects beyond undesirable aesthetic qualities.
If possible, CMWD should attempt to ease the Regional Board’s limits of manganese that
are applicable to recycled water. In addition, the manganese concentration of water
received from the MWD’s Skinner plant is, on average, about 0.02 mg/L. This suggests that
an industrial user in the City might be discharging manganese to the sewer. If possible,
CMWD should also attempt to discern the source of manganese in the collection system. If
the Regional Board does not ease the manganese limits, or if CMWD is unable to discern
the source of the additional manganese, additional treatment at the Carlsbad WRF plant will
be required since running the spare reverse osmosis units for manganese removal is an
expensive method for manganese removal. For the purposes of this study, it is assumed
that additional MF/RO capacity will not be required when the Carlsbad WRF is expanded in
the future.
Total Dissolved Solids (TDS)
As discussed previously, Carlsbad WRF was designed for granular media filtration of
80 percent of the influent flow and MF/RO filtration for the remaining 20 percent of the
influent flow. The MF/RO treatment was included to reduce TDS levels in the secondary
effluent from the Encina Water Pollution Control Facility (EWPCF). The 1997 RWMP
describes TDS levels ranging above 1,300 mg/L. In discussions with CMWD staff, it was
learned that after the Carlsbad WRF came online, an investigation was conducted to
determine the source of the high TDS levels. This investigation identified a specific user
discharging seawater into the sewer system. Once this discharge was discontinued, the
TDS levels in EWPCF’s secondary effluent were reduced. Based on the lowered TDS
levels, it is assumed that future expansions of Carlsbad WRF will not require additional
MF/RO capacity.
4.2.4 Supply from Seasonal Storage
Since CMWD’s demands are primarily landscape irrigation in nature, peak demands occur
seasonally. Seasonal storage can be used to buffer the peak seasonal flows when the daily
demands exceed the supply capacity of the supply sources in lieu of expanding plant
capacity. In order to use seasonal storage as a supply, excess supply in months of low
seasonal demand must be placed into seasonal storage to be pulled out in months where
demand exceeds supply capacity. One of the key challenges with seasonal storage as a
source of supply is to limit utilization of seasonal storage supplies before the peak months.
Otherwise, supply shortages may occur.
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A sample supply strategy for supply planning with seasonal storage is presented in
Figure 4.3. Based on the usable existing supply capacity of 7.6 mgd (see Table 4.1) and a
seasonal storage capacity of 32 MG (CMWD’s allocation capacity in Mahr Reservoir),
CMWD could meet an average annual demand of 4.9 mgd based on the current seasonal
peaking behavior of CMWD’s customer. This corresponds to a maximum month demand of
8.3 mgd using a peaking factor of 1.7 (see Table 3.5).
Figure 4.3 Seasonal Storage Requirement
Hence, the existing seasonal storage capacity would be sufficient to provide about 0.7 mgd
of supply during summer months. Assuming that the 32 MG is available, this corresponds to
45 days of 1.5 months.
Currently, CMWD has adequate supply capacity such that seasonal storage is not
necessary. However, as CMWD’s peak summer demands grow, taking advantage of
seasonal storage can delay treatment plant upgrades. In addition, it should be noted that
Mahr Reservoir historically has experienced the following issues:
• Water quality issues related to algae growth.
• Low reservoir levels related to insufficient flows from Meadowlark WRF.
January 2012 4-11 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4
These issues are interrelated as low water levels result in higher water temperatures, which
then causes more algae growth. As Mahr Reservoir is located south from the Meadowlark
WRF, the majority of reservoir outflow goes to OMWD’s system, while CMWD receives
treated water from Meadowlark WRF. When Meadowlark WRF produces more than
CMWD’s demand, the remaining flow is directed to Mahr Reservoir. Due to this system
configuration, OMWD receives more water from Mahr Reservoir than CMWD and
experiences the related water quality issues. OMWD is therefore interested in reducing its
take from Mahr Reservoir and obtaining recycled water from the Carlsbad WRF through a
new pipeline connection along El Camino Real. As this new connection enters OMWD’s
system in the lower zones, the higher zones that are currently fed from Mahr Reservoir can
only be served if additional pumping stations and east-west pipelines are constructed to
connect the lower and higher pressure zones in OMWD’s recycled water system. As this
expansion of OMWD’s system is not likely to happen in the near future, it is assumed that
OMWD will maintain its current take from Meadowlark WRF and its 18 MG share in Mahr
Reservoir. For planning purposes, it is therefore assumed that CMWD’s seasonal storage
capacity in Mahr Reservoir remains 32 MG.
4.2.5 Potential Future Supply Sources
CMWD is approaching a supply shortfall once the future demands are realized. There are
various options to address this shortfall and expand the recycled water supply capacity.
These options are discussed below and include:
• Expansion of Carlsbad WRF
• Increased allotment from Meadowlark WRF to CMWD
• Increased supply from Gafner WRP by connecting Gafner WRP to CMWD’s recycled
water system via a pump station and pipelines
• Re-activation and connection to Shadowridge WRF
• Surface water treatment plant for stormwater runoff into Lake Calavera
An expansion of Carlsbad WRF could be one potential source of additional supply.
According to the 2001 Influent Pumping and Equalization Preliminary Design Report (MWH,
2001), the ultimate design capacity of the Carlsbad WRF is 16 mgd. While the report only
quantifies the necessary changes required to the pumping system to accommodate the
additional capacity, it is assumed that the rest of the facility is designed such that it can also
accommodate the treatment expansions to reach the ultimate capacity of 16 mgd.
A second alternative could be securing additional supply from Meadowlark WRF. Since the
historic limitation to supply from Meadowlark WRF has been low influent wastewater flows,
this would most likely need to consist of obtaining some of OMWD’s allocation in exchange
for supplying some of OMWD’s lower zone demand from CMWD’s system. Based on
discussions with CMWD staff, it is anticipated that influent wastewater flows to Meadowlark
WRF will not exceed 4 mgd, resulting in a maximum supply of about 3.5 mgd.
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A third source of additional supply could be connection of the Gafner WRP to the rest of
CMWD’s recycled water system. As discussed previously, CMWD’s current utilization of
Gafner WRP is less than its rated capacity. It is possible that the remaining capacity could
be used within the rest of CMWD’s recycled water system or expansion could increase
potential supply from Gafner WRP. A technical memorandum completed for Leucadia
Wastewater District (LWWD) in October 2010 indicated an expansion of up to 3.7 mgd
would cost approximately $35.8 million.
In addition, the Shadowridge WRP, owned by the Buena Sanitation District (BSD), is
currently not in service. However, a study dated September 2010 by PBS&J for the City of
Vista evaluated reactivation of the plant. Three alternatives were analyzed, and a 2-mgd
MBR process was noted as “may be cost-effective”. If reactivated, 1 mgd of effluent would
be allocated to the adjacent Shadowridge Golf Course, park, and high school, while the
remaining 1 mgd could be available to CMWD. However, the analysis assumed that CMWD
would need to accept the full flow of the facility throughout the year, less than used by the
Shadowridge Golf Course. Similar to Meadowlark WRF, Shadowridge WRP is intended to
operate as a “skimming” plant, discharging solids into a solids discharge pipeline, which is
also referred to as the failsafe pipeline. Solids are ultimately treated at the EWPCF. The
locations of the Shadowridge WRP as well as the failsafe pipeline are shown on Figure 4.4.
The Lake Calavera supply option would divert water from Lake Calavera to a treatment site
located at either the southwest or the southeast corner of Cannon Road and College
Boulevard. Flow would be delivered to the treatment site via a new gravity line located in an
existing sewer main easement. Based on similar treatment of surface water sources,
treatment for Lake Calavera water would most likely consist of coagulation through a rapid
mix tank and a flocculation tank, sedimentation, filtration, and chlorine addition. Depending
on the measured water quality, the actual designed treatment process could change. If the
water has both low turbidity and color (less than 25 units), Lake Calavera water treatment
could consist of only direct filtration. For this study, the worst case (turbidity and color
greater than 25 units) was assumed.
The locations of each of CMWD’s existing facilities as well as the potential future supply
sources are shown on Figure 4.4.
Carlsbad WRF
Gafner WRP
Mahr Reservoir
Meadowlark WRF
Agua HediondaLagoonEl Ca
mi
no Rea
l
E lm A v e
Marron Rd
C
arls
b
a
d B
lv
d Hi
g
hl
a
n
d
D
r
Paseo NorteC ollege B lvdP a lo m a r A irp o rt R D
Aviara Pkwy El Fuerte StCosta Ave
P o in s e ttia L n
T a m a ra c k A v e
Cannon Rd
Calle BarcelonaRanc ho Santa FeEncina Water Pollution Control Facility
Pacific Ocean
Encinitas
Batiquitos Lagoon
Buena VistaLagoon Oceanside
Shadowridge WRP
Lake Calavera
"C" Tank
Twin "D" Tanks
OMWDMeter
Corintia Meter
Olivenhain MunicipalWater DistrictSan DieguitoWater District
VallecitosWater District
Vista Irrigation District
Proposed Calavera Stormwater Treatment Facility
8"
San Marcos
Vista
Encinitas
Oceanside
1 2"E n c in a O u tfa ll24"
16"36"14"
12"
10''
30''24''8''12''12''8''12''
1 2 ''4''8''12''20''6''4''
4''
4''6''12''
18''
4''
20''
8''8''8''
1 2 ''8 ''12''12''12''1 2 ''8 ''4 ''18''
4''12''12''12''4'
'4''12''
8''12''8''
8 ''8''
8''
8''8''
12''16''30''12''1
2
''
8''
1
6''
8 ''14''8''12''8''8''8''
1 2 ''6''
8''12''
8 ''8 ''
8''8''24''
12''30''8''12''6''
12''
8''
8''4''6''
12''8''1 2 ''8'
'24''27''
8''8''
12''
8''
12 ''
24 ''
8''
4 ''
6''14''16''8''12''8''12''8 ''8''8''
1
6''
1 2 ''1 2 ''1
2''
8''20''10''12''
1 2 ''10''
8 ''8''12''12''8''
12''8''8''6''
12''30''8''
8''6''8''18''8''8''8''8''8''8''6''2 4 ''18''
8''24''
0 5,000 10,000
Feet
Figure 4.4Supply Sources
Recycled Water Master PlanCarlsbad Municipal Water District
FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_4_1-Supply_Sources.mxdDATE: 5/18/2011Potable Water Connection
Supply Source ProcessesRated Capacity
(mgd)
Carlsbad WRF 4.0 Tertiary
Meadowlark WRF 5.0 Primary, Secondary
Gafner WRP 1.0 Tertiary
Potable Water
Connection (D Tanks)4.3 n/a
Potable Water Connection (VWD)
Legend
Distribution Pipeline
12" and Smaller
14" and Larger
Recycled Water Facility
Proposed Treatment Facility
Existing WRF
Tank
Encina
Reservoir
Potable Water
Meter
Inactive WRP
Treatment Related Pipelines
Encina Outfall
Failsafe Pipeline
Failsafe Pipeline
(Secondary Effluent to Gafner WRF)
Other
Freeways
Local Streets
Carlsbad City Limits
Water Body
San Diego County
Carlsbad Municipal Water District Boundary
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4.3 SUPPLY REQUIREMENTS
As described in Chapter 3, CMWD’s existing system recycled water average annual
demand is assumed as 4,000 acre-feet per year (afy) (3.6 mgd), with a corresponding
maximum month demand of 6.1 mgd. The potential build out demand including demand for
neighboring agencies is estimated at 9,106 afy (8.1 mgd) with a corresponding maximum
month demand of 13.5 mgd. The general phasing of demands is presented in Table 4.4.
Table 4.4 Summary of Recycled Water Demands Recycled Water Master Plan Carlsbad Municipal Water District
Condition
Average Annual
Demand
(afy)
Average Day
Demand
(mgd)
Maximum Month
Demand(1)
(mgd)
Existing 4,000 3.6 6.1
Near-Term (Phases I and II)(2) 4,100 3.7 6.2
CMWD Build-out System(3) 7,144 6.4 10.8
Build-out System with Neighboring Agencies(4) 9,106 8.1 13.5
Notes: (1) Assumes a Maximum Month Demand seasonal peaking factor (PF) based on individual customer peaking factors listed in customer database (see Appendix C).
(2) Includes 100 afy of Near Term / In Progress demands discussed in Chapter 3. (3) Near-Term + Customer Database demands inside CMWD service area discussed in Chapter 3 less customers determined not feasible for connection in Chapter 9. Includes Areas of Potential Development
discussed in Chapter 3. (4) Near-Term + Customer Database demands discussed in Chapter 3 less customers determined not feasible for connection in Chapter 9. Includes Areas of Potential Development discussed in Chapter 3.
The projected water demands as listed in Table 4.4 and the existing supply allocation of
7.6 mgd during summer months are graphically depicted in Figure 4.5. As shown, the
maximum month build-out demand associated with connection of all feasible customers
within CMWD’s service area, identified in Chapter 9, is 10.8 mgd. When compared with
CMWD’s existing supply allocation of 7.6 mgd, CMWD will need to find an additional
3.2 mgd of supply to serve CMWD’s build-out system.
The MMD demand associated with connection of all feasible customers including those in
neighboring agencies is 13.5 mgd. Hence, nearly 6 mgd of additional supply would be
required to serve the build-out system including the demands identified outside CMWD’s
service area.
While CMWD has sufficient supply capacity for its Existing and Near-Term demands, it is
anticipated that as future demands are added to CMWD’s system as a part of Phase III,
CMWD will need to develop new supply sources to expand its recycled water system. The
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required supply capacity to meet the projected MMD for each phase and the associated
supply shortfalls are summarized in Table 4.5.
6.1 6.2
10.8
13.5
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
Existing Near-Term (Phase I
and II)
CMWD Build-out
System
Build-out System
with Neighboring
AgenciesMaximum Month Demand (mgd)Usable Supply Capacity (7.6 mgd)
Figure 4.5 Maximum Month Demand
Table 4.5 Summary of Supply Requirements Recycled Water Master Plan
Carlsbad Municipal Water District
Description
Near-Term
(Phase I and II)
CMWD Build-out
System
Build-out System
with Neighboring
Agencies
ADD (mgd) MMD (mgd) ADD (mgd) MMD (mgd) ADD (mgd) MMD (mgd)
Demand 3.7 6.2 6.4 10.8 8.1 13.5
Existing Supply Capacity 7.6 7.6 7.6 7.6 7.6 7.6
Supply Balance +3.9 +1.4 +1.2 -3.2 -0.5 -5.9
As shown in Table 4.5, CMWD will experience a supply shortfall of just over 3 mgd when all
potential customers are connected within the CMWD service area, and just under 6 mgd
when all potential demands from neighboring agencies are connected. For planning
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purposes, a MMD supply capacity of 11 mgd is assumed to be required for connection of all
feasible customers within CMWD’s service area while an MMD supply capacity of 14 mgd is
assumed for connection of all feasible customers including those in neighboring agencies.
Various alternatives to meet these supply requirements are discussed in the next section.
4.4 SUPPLY EVALUATION
Based on discussions with CMWD staff, six different supply alternatives were developed.
Each alternative has an assumed total build out supply capacity of 14 mgd, based on the
demands presented in Chapter 3 and the feasibility study discussed in Chapter 9. The unit
supply cost of each alternative as expressed in dollars per acre-foot ($/af) was used for
relative comparison purposes. The six supply alternatives that will meet the 14-mgd
capacity goal are summarized in Table 4.6.
Table 4.6 Supply Alternatives Summary Recycled Water Master Plan
Carlsbad Municipal Water District
Supply Source Facility
Treatment Flow(1) (mgd) Alternative 1 Maximize CWRF Alternative 2 Maximize MWRF Alternative 3 Maximize GWRP Alternative 4 Abandon GWRP Alternative 5 Maximize CWRF and Lake Calavera Alternative 6 Utilize Shadowridge WRP Carlsbad WRF 10.25 9.75(3) 7.00 11.00 9.00 9.75
Meadowlark WRF 3.00 3.50 3.00 3.00 3.00 3.00
Gafner WRP(4) 0.75 0.75 4.00 - 0.75 0.75
Calavera Reservoir SWTF - - - - 1.00 -
Seasonal Storage - - - - 0.25 0.20
Shadowridge WRP - - - - - 0.30
Total 14.00 14.00(5) 14.00 14.00(5) 14.00 14.00
Notes:
WRF = Water Reclamation Facility; WRP = Water Reclamation Plant; SWTF = Stormwater Treatment Facility
(1) Treatment Flow under MDD conditions. For Alternative 6, Shadowridge WRP would have a treatment capacity of 1.0 mgd, but would only supply 0.3 mgd under MDD conditions.
(2) MMD for Gafner WRP did not occur during the same month as MMD for Carlsbad WRF and Meadowlark WRF during 2010. Note that although Gafner WRP’s allocation is 0.75 mgd, it is not connected to the rest of the system and is currently only able to supply La Costa Resort and Spa south golf course).
(3) OMWD would be connected to the CMWD system thus freeing capacity at the Meadowlark WRF; however, in addition to the expansion shown here, CWRF would need to be expanded to accommodate the additional 1.4 mgd of OMWD demands planned to be supplied from MWRF for a total CWRF plant
capacity of 11.15 mgd.
(4) Demands for Gafner WRP assumed connection of Gafner WRP to the rest of the system for all alternatives except Alternative 4.
(5) Total does not include additional expansion capacity of 1.4 mgd allocated to OMWD from CWRF
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The treatment processes and other improvements such as, pipelines and booster pump
stations are summarized by supply source in Table 4.7. The capacity and size of the
required expanded facilities varies for each alternative as described in the following
sections.
Table 4.7 Facilities Required for Expansion Recycled Water Master Plan
Carlsbad Municipal Water District
Supply Source Required Facilities(1)
Carlsbad WRF Tertiary Filters(2) Chlorine Contact Basins Effluent Pumping(3)
Meadowlark WRF(5) - -
Gafner WRP(4) Tertiary Filters
Chlorine Contact Basins
Influent Force Main
Effluent Pumping Transmission Main
Calavera Stormwater Facility Screenings Sedimentation
Flocculation Basins
Filtration Rapid Mix Chamber
Chlorine Contact Basins
Transmission Main(6)
Shadowridge WRP(7) Headworks
Primary Clarifiers Odor Control Facilities
Aeration Basins
Blower Building
Secondary Clarifiers Tertiary Filters
Chlorine Contact Basins
Notes:
(1) Required facilities include associated yard and electrical work.
(2) Carlsbad WRF’s existing MF/RO system and filters treat 20 percent and 80 percent of the flow, respectively. Flow from both processes is blended prior to distribution. Expansions are not anticipated to require MF/RO based on discussions with CMWD staff.
(3) Carlsbad WRF currently has 14.4 mgd of effluent pumping capacity (3 duty - no standby)
(4) The 12-inch diameter transmission main proposed in Chapter 9 would need to be increased to a 16-inch diameter transmission main to connect GWRP effluent to CMWD’s distribution system. Pipeline size is
based on a 3.4-mgd flow since 0.6 mgd will be delivered to the La Costa golf course, which is adjacent to the GWRP.
(5) Since Meadowlark WRF is limited by wastewater influent flow, no expansion is anticipated.
(6) An 8-inch diameter transmission main is required for connecting the stormwater treatment plant to CMWD’s distribution system.
(7) As a part of discussions between CMWD and VID, preliminary cost estimates for three alternatives were
developed and are discussed in Section 4.4.6. Details on which facilities are included in the expansion were not available. VID’s study on reactivation of Shadowridge WRP also discusses alternatives for delivery of the effluent to CMWD’s distribution system. These alternatives are discussed in further detail
below.
It should be noted that all three water reclamation treatment plants (Carlsbad WRF, Gafner
WRP, and Meadowlark WRF) are part of the Encina Wastewater Authority (EWA) and
operate off the EWA’s joint collection system. At the end of the collection system is the
Encina Water Pollution Control Facility (EWPCF) with a flow capacity of 40.5 mgd, a solids
capacity of 43.3 mgd, and an ocean outfall with a flow capacity of 43.3 mgd. The EWPCF
treats wastewater to secondary treatment standards. The Carlsbad WRF and the Gafner
WRP are tertiary scalping plants. Secondary effluent from the EWPCF is pumped to the
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Carlsbad WRF and the Gafner WRP for tertiary treatment. EWA also has two wastewater
scalping plants upstream in the joint collection system, the Meadowlark WRF and the
Shadowridge WRP.
The unit costs for each alternative will be based on the potential annual demand, which is
made possible by the expansion. The total existing MMD supply capacity is 7.75 mgd.
However, since Gafner WRP is not currently connected to the rest of the system, utilization
of the full allocated capacity of Gafner WRP will only be possible if it is connected to the
rest of the system. For relative comparison, it is assumed that Gafner WRP will be
connected to the rest of the system at build-out and relative costs for the connection are
included in each alternative. Based on the seasonal peaking factor of 1.7, the existing MMD
supply capacity of 7.6 mgd corresponds to an average annual demand of 5,008 afy. Based
on an average annual build-out demand of 9,106 afy, unit costs for each expansion were
assumed to add 4,098 afy of potential demand. Note that this unit cost is based on the
average annual demand added to the system, not the utilization of the plant.
4.4.1 Alternative 1 – Maximize Carlsbad WRF
This alternative consists of CMWD’s current supply mix using recycled water from the
Carlsbad WRF, Meadowlark WRF, and the Gafner WRP. The capacities of the Gafner
WRP and Meadowlark WRF remain as existing in this alternative providing 0.75 and
3.0 mgd, respectively. The use of the Carlsbad WRF is maximized in this alternative, which
will thereby provide the balance of the required supply. The Carlsbad WRF is therefore the
only plant expansion in this alternative and would need to be increased from 4.0 mgd to
10.25 mgd to provide a combined supply capacity of 14.0 mgd. In addition, a pipeline and
pump station are included to connect the Gafner WRP to the rest of the distribution system,
allowing full utilization of the 0.75 mgd allocation of Gafner WRP.
As stated previously, the Carlsbad WRF was originally sized to be increased up to 16 mgd,
and it is therefore assumed that all expansions can be accommodated at the current site.
The process flow diagrams for each plant are shown on Figure 4.6. As EWPCF already has
a secondary treatment capacity of 40.5 mgd, only tertiary treatment processes, disinfection,
and effluent pumping capacity needs to be upgraded as part of this alternative. As the plant
already has 14.4 mgd (10,000 gpm) of effluent pumping capacity, no additional effluent
pumping capacity is needed to meet MMD. However, if the Carlsbad WRF is used to meet
Peak Hour Demands (PHD), additional pumping capacity will be needed. Based on
discussions with CMWD staff, Carlsbad WRF will not require spare pumping capacity since
Mahr Reservoir can be used to supply Carlsbad WRF in event of a pump outage.
21-Carlsbad610Fig4.6-8308A00.aiPROCESS FLOW DIAGRAMSFIGURE 4.6CARLSBAD MUNICIPAL WATER DISTRICTWastewaterCollectionSystemHeadworks PrimaryClarifiersRoughingFiltersAerationBasinSecondaryClarifiersTertiaryFiltersChlorineContactBasinEffluentPumpingHeadworksPrimaryClarifiersAerationBasinSecondaryClarifiersOceanOutfallExisting 40.5 mgd Encina Water Pollution Control FacilitiesStormwaterRunoffCalaveraReservoirFiltrationSecondaryEffluentExisting 1 mgd Gafner Water Reclamation PlantTertiaryFiltersChlorineContactBasinEffluentPumpingChlorineContactBasinEffluentPumpingTertiaryFiltersMicrofiltrationReverseOsmosis20% of Flow80% of FlowSecondaryEffluentExisting 4 mgd Carlsbad Water Reclamation FacilityPotential 1 mgd Calavera Stormwater Treatment FacilityScreeningsRecycled Water UsersExisting 5 mgd Meadowlark Water Reclamation PlantHeadworksPotential 2 mgd Shadowridge Water Reclamation PlantHeadworks PrimaryClarifiersRoughingFiltersAerationBasinSecondaryClarifiersTertiaryFiltersChlorineContactBasinEffluentPumpingRapidMixFlocculationSedimentationBasinCoagulant Auxiliary ChemicalChlorineInjection
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To determine the capital construction cost of this alternative, the following key components
were included:
• 6.25 mgd tertiary filter capacity expansion at Carlsbad WRF.
• 6.25 mgd chlorine contact basin capacity expansion at Carlsbad WRF.
• No additional effluent pumping capacity at Carlsbad WRF.
• 1,500 feet of 8-inch diameter pipeline and 75 hp pump station sized for 0.75 mgd to
convey flow from Gafner WRP to distribution system (future Expansion Segment 8 in
El Camino Real).
The estimated capital cost of this alternative is $10.8 million. Based on a 30-year
repayment period and 6-percent interest, the annual cost is estimated at about $785,000. A
detailed breakdown of this estimate is included in Appendix B. Assuming an annual
demand of 4,098 afy made possible by this expansion, the unit supply cost of this
alternative is hereby estimated at $191/af.
4.4.2 Alternative 2 - Maximize Meadowlark WRF
This alternative consists of CMWD’s current supply mix using recycled water from the
Carlsbad WRF, Meadowlark WRF, and the Gafner WRP. The utilization of Gafner WRP
would again increase in this alternative since Gafner WRP would be connected to the
system providing 0.75 mgd during MMD conditions. The use of Meadowlark WRF is
maximized by taking the available 3.5 mgd of supply versus the current 3.0 mgd.
This alternative therefore assumes that OMWD would no longer take supply from
Meadowlark WRF, but instead obtain recycled water from the Carlsbad WRF through
CMWD’s distribution system. This would require OMWD to modify its distribution system by
adding several booster pumping stations to obtain flow from lower zones in its distribution
system. The Carlsbad WRF would also need to be expanded to provide the balance of the
required supply for both CMWD and OMWD.
Based on discussions with OMWD staff, OMWD’s existing demands are 700 afy,
anticipated to increase to 1,300 afy in the future. As discussed in Chapter 3, the customer
database includes 500 afy for OMWD delivered in the lower zones. Since the 500 afy is
already accounted for within CMWD’s build-out demand of 9,106 afy, the remaining
additional demand, which would need to be supplied from Carlsbad WRF, would be
800 afy. Based on a seasonal peaking factor of 2.0 (specific to OMWD’s system), the
estimated MMD would be 1.4 mgd.
The Carlsbad WRF is the only plant expansion in this alternative and would need to be
increased from 4.0 to 11.15 mgd to provide an additional 5.75 mgd for CMWD and 1.4 mgd
to OMWD.
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It is assumed that the proposed expansion of the Carlsbad WRF from 4 mgd to 11.15 mgd
can be accommodated at the current site and that this expansion will be limited to the
tertiary treatment processes, disinfection, and effluent pumping capacity. As the plant
already has approximately 14.4 mgd of effluent pumping capacity, it is not anticipated that
the pump station will need to be expanded to meet a MMD of 11.15 mgd. However, if the
pump station at Carlsbad WRF is used to meet PHD, additional pumping capacity will be
needed.
To determine the capital construction cost of this alternative, the following key components
were included:
• 5.75-mgd tertiary filter capacity expansion at Carlsbad WRF.
• 5.75-mgd chlorine contact basin capacity expansion at Carlsbad WRF.
• No additional effluent pumping capacity at Carlsbad WRF.
• Transmission main from CMWD’s distribution system to OMWD’s distribution system
(the 12-inch diameter, 5,500-foot long pipeline proposed along El Camino Real in
Chapter 9 would need to be increased in size to 16 inches in diameter).
• Two booster pumping stations within OMWD’s system, so that OMWD can take
supply from its lower zones.
• 1,500 feet of 8-inch diameter pipeline and 75 hp pump station sized for 0.75 mgd to
convey flow from Gafner WRP to distribution system (future Expansion Segment 8 in
El Camino Real).
The overall capital cost of this alternative is estimated at $16.9 million. A detailed
breakdown of this estimate is included in Appendix B. Assuming an annual demand of
4,098 afy made possible by this expansion, the unit supply cost is estimated at $300/af.
This alternative would be more feasible if Meadowlark WRF wastewater influent flows
would increase in the near future, creating a new supply source without the need of
expanding CWRF for OMWD. However, this alternative is not possible given the anticipated
influent flows to Meadowlark WRF.
4.4.3 Alternative 3 - Maximize Gafner WRP
This alternative consists of CMWD’s current supply mix using recycled water from the
Carlsbad WRF, Meadowlark WRF, and the Gafner WRP. The Meadowlark WRF remains at
its current capacity in this alternative, providing 3 mgd. The use of Gafner WRP is
maximized by increasing the supply capacity to 4 mgd. As Gafner WRP treats secondary
effluent from the EWPCF, this plant expansion would only require additional Microfiltration
and Reverse Osmosis Treatment, disinfection, and effluent pumping. MF/RO treatment
would be used to both accommodate limited space constraints and water quality
constraints. The use of this additional supply would require the installation of 5,000 feet of
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12-inch diameter pipeline along El Camino Real from the Gafner WRP to the intersection
with Aviara Parkway. This pipeline, along with a new booster pumping station, would
provide a direct connection with Zone 384. This 3-mgd booster station would need to
provide sufficient head to deliver recycled water into Zone 384 to serve other customers in
CMWD from Gafner WRP. It should be noted that the basin plan for the La Costa Golf
Course area, between El Camino Real and Highway 78 (Batiquitos Hydrologic Sub Area
4.51), does not have any limits on TDS and Manganese. When Gafner WRP is expanded
and used to serve new CMWD customers, more stringent regulations from other basin
plans apply. Water quality could therefore be a potential issue when maximizing this supply
source.
In addition, the Carlsbad WRF would be expanded to provide the balance of the required
supply. The Gafner WRP and Carlsbad WRF would be expanded by 3.0 mgd each, to
provide a combined supply capacity of 14.0 mgd (since Gafner WRP would be connected to
the system, it is assumed that the full capacity of 1.0 mgd could be used).
It is assumed that the proposed expansion of the Carlsbad WRF from 4.0 mgd to 7.0 mgd
can be accommodated at the current site and that this expansion will be limited to the
tertiary treatment processes, disinfection, and effluent pumping capacity. As the plant
already has approximately 14.4 mgd of effluent pumping capacity, no additional pumping
capacity at Carlsbad WRF is anticipated. However, if the pump station at Carlsbad WRF is
used to meet PHD, additional pumping capacity will be needed.
To determine the capital construction cost of this alternative, the following key components
were included:
• 3-mgd treatment plant upgrade at the Gafner WRP using MF/RO and chlorine contact
basins for disinfection.
• 3.4-mgd discharge pumping station to serve Zone 384. A supply of 0.6 mgd will
continue to be delivered to the La Costa Golf Course.
• Replace secondary effluent force main from EWPCF supplying Gafner WRP influent
(estimated at 16-inch diameter, 27,000 feet).
• 3-mgd tertiary filter capacity expansion at Carlsbad WRF.
• 3-mgd chlorine contact basin capacity expansion at Carlsbad WRF.
• Transmission main from Gafner WRP to CMWD’s distribution system (the 12-inch
diameter, 5,000-foot long pipeline proposed along El Camino Real in Chapter 9 would
need to be increased in size to 16 inches in diameter).
The estimated capital cost of this alternative is $73.6 million. A detailed breakdown of this
estimate is included in Appendix B. Assuming an annual demand of 4,098 afy made
possible by this expansion, the unit supply cost of this alternative is estimated at $1,305/af.
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4.4.4 Alternative 4 - Abandon Gafner WRP
This alternative is similar to Alternative 1; however, it eliminates the use of Gafner WRP.
Consequently, the Carlsbad WRF would need to be expanded to provide the entire balance
of the required supply of 14.0 mgd for CMWD. The Carlsbad WRF is the only plant
expansion in this alternative and would need to be increased from 4.0 to 11.0 mgd to
provide an additional 7.0 mgd for CMWD. This expansion includes the 0.6 mgd to replace
lost capacity from the Gafner WRP.
Similar to Alternative 1, it is assumed that the proposed expansion of the Carlsbad WRF
from 4.0 mgd to 9.7 mgd can be accommodated at the current site and that this expansion
will be limited to the tertiary treatment processes and disinfection. As the plant already has
approximately 14.4 mgd of effluent pumping capacity, no additional pumping capacity is
anticipated. However, if the pump station at Carlsbad WRF is used to meet PHD, additional
pumping capacity will be needed.
To determine the capital construction cost of this alternative, the following key components
were included:
• 7-mgd tertiary filter capacity expansion at Carlsbad WRF.
• 7-mgd chlorine contact basin capacity expansion at Carlsbad WRF.
• No additional effluent pumping capacity at Carlsbad WRF.
• 1,500 feet of 8-inch diameter pipeline to convey flow from the distribution system to
the Gafner WRP site to supply La Costa Resort and Spa south golf course demands.
The proposed pipeline size in Chapter 9 is predicted to have sufficient capacity to convey
the La Costa Resort and Spa south golf course (Gafner WRP’s only existing customer)
MMD of 0.6 mgd in addition to the demands associated with Expansion Segment 8.
The estimated capital cost of this alternative is $10.2 million. A detailed breakdown of this
estimate is included in Appendix B. Assuming an annual demand of 4,098 afy made
possible by this expansion, the unit supply cost of this alternative is estimated at $181/af.
Note that costs for abandonment of Gafner WRP and the cost benefit of wholesale costs to
LWWD are not considered.
4.4.5 Alternative 5 - Maximize Carlsbad WRF and Lake Calavera
This alternative expands CMWD’s current supply mix by developing a new supply source
from Lake Calavera while continuing to use recycled water from the Carlsbad WRF,
Meadowlark WRF, and the Gafner WRP. Meadowlark WRF remains at current capacity in
this alternative providing 3.0 mgd. Gafner WRP is connected to the distribution system,
allowing full utilization of the 0.75 mgd allocation. Carlsbad WRF is expanded from 4.0 mgd
to 9.0 mgd. The balance of 0.25 mgd is assumed to be supplied from seasonal storage in
the peak month.