APPENDIX A: SURFACE WATER HYDROLOGY SANTA ANA RIVER WATER RIGHT APPLICATIONS FOR SUPPLEMENTAL WATER SUPPLY DRAFT ENVIRONMENTAL IMPACT REPORT October 2004 ANRRDEIBNONAVSALLEYMUNICIPTACILRWTASITDER TABLE OF CONTENTS 1.0 INTRODUCTION..........................................................................................................................A-1-3 2.0 SANTA ANA RIVER SYSTEM....................................................................................................A-2-3 2.1 Santa Ana River Watershed..............................................................................................A-2-3 2.2 Characteristics of the Santa Ana River and Its Tributaries..........................................A-2-3 2.2.1 Measurement of Stream Flow and Stream Flow Variability.........................A-2-3 2.2.2 Tributaries...............................................................................................................A-2-3 2.2.2.1 Mill Creek...............................................................................................A-2-3 2.2.2.2 Lytle Creek............................................................................................A-2-3 2.2.3 Recent and Anticipated Changes in the Santa Ana River Flow Regime.....A-2-3 2.2.3.1 Wastewater Treatment Plant (WWTP) Discharges.........................A-2-3 2.2.3.2 Increased Urbanization........................................................................A-2-3 2.2.3.3 Seven Oaks Dam...................................................................................A-2-3 2.2.4 Past and Future Flooding, Sediment Transport, and Overbank Flows of the Santa Ana River..........................................................................................A-2-3 2.2.4.1 Flooding..................................................................................................A-2-3 2.2.4.2 Fluvial Processes....................................................................................A-2-3 2.3 Water Quality.......................................................................................................................A-2-3 2.3.1 Beneficial Use.........................................................................................................A-2-3 2.3.2 Components of Water Quality and Water Quality Characteristics..............A-2-3 2.3.3 Water Quality Measurement Activities.............................................................A-2-3 2.3.4 Existing Water Quality.........................................................................................A-2-3 2.3.5 Imported Water Quality.......................................................................................A-2-3 2.4 Regulatory and Institutional Setting................................................................................A-2-3 2.4.1 The Orange County Judgment............................................................................A-2-3 2.4.2 The Western Judgment.........................................................................................A-2-3 2.4.3 State Water Resources Control Board Orders..................................................A-2-3 2.4.4 Senior Water Rights Claimants and Seven Oaks Accord...............................A-2-3 2.4.5 Conservation District............................................................................................A-2-3 2.4.6 Santa Ana River-Mill Creek Cooperative Water Project Agreement...........A-2-3 2.4.7 Big Bear Lake Operations.....................................................................................A-2-3 2.5 Santa Ana River Segments.................................................................................................A-2-3 2.5.1 Segment A, Upstream of Seven Oaks Dam......................................................A-2-3 2.5.1.1 Major Features.......................................................................................A-2-3 2.5.1.2 SAR Characteristics...............................................................................A-2-3 2.5.2 Segment B, Seven Oaks Dam to Just Above Cuttle Weir...............................A-2-3 2.5.2.1 Major Features.......................................................................................A-2-3 2.5.2.2 Santa Ana River Characteristics.........................................................A-2-3 2.5.3 Segment C, Cuttle Weir to just above the Confluence of Mill Creek...........A-2-3 2.5.4 Segment D, Mill Creek Confluence to just above “E” Street.........................A-2-3 2.5.5 Segment E, “E” Street to just above the RIX and Rialto Effluent Outfall....A-2-3 Santa Ana River Water Right Applications for Supplemental Water Supply Draft EIR A-i October 2004 Appendix A - Surface Water Hydrology 2.5.6 Segment F, RIX and Rialto Effluent Outfall to just above Riverside Narrows.................................................................................................A-2-3 2.5.7 Segment G, Riverside Narrows to Prado Dam................................................A-2-3 3.0 HYDROLOGIC BASE PERIOD DETERMINATION..............................................................A-3-3 3.1 Introduction..........................................................................................................................A-3-3 3.2 Determining the Appropriate Base Period Using Rainfall Data................................A-3-3 3.3 Determining the Appropriate Base Period Using Runoff Data..................................A-3-3 3.4 Selection of a Base Period..................................................................................................A-3-3 4.0 OPERATIONS MODEL (OPMODEL).......................................................................................A-4-3 4.1 Overview of OPMODEL....................................................................................................A-4-3 4.2 General Description and Purpose of OPMODEL..........................................................A-4-3 4.2.1 Model Structure.....................................................................................................A-4-3 4.2.2 Model Inputs, Parameters, and Assumptions..................................................A-4-3 4.2.2.1 Seven Oaks Dam Inflow and Storage................................................A-4-3 4.2.2.2 Operations at Seven Oaks Dam..........................................................A-4-3 4.2.2.3 Releases from Seven Oaks Dam.........................................................A-4-3 4.2.2.4 Unappropriated Santa Ana River Water and Muni/Western Diversions...............................................................................................A-4-3 4.2.3 Model Application (Methodology)....................................................................A-4-3 4.2.4 Model Results.........................................................................................................A-4-3 5.0 ALLOCATION MODEL...............................................................................................................A-5-3 5.1 General Description and Purpose of Allocation Model...............................................A-5-3 5.2 Model Structure...................................................................................................................A-5-3 5.3 Model Input, Parameters, and Assumptions.................................................................A-5-3 5.3.1 Priorities for Water Allocation............................................................................A-5-3 5.3.1.1 Direct Use – Priority 1..........................................................................A-5-3 5.3.1.2 Groundwater Recharge in the San Bernardino Basin Area – Priority 2.................................................................................................A-5-3 5.3.1.3 Other Groundwater Recharge in Muni Service Area - Priority 3.................................................................................................A-5-3 5.3.1.4 Exchange - Priority 4.............................................................................A-5-3 5.3.2 Future Conditions in Muni/Western Service Areas.......................................A-5-3 5.3.3 Future Demands in the Muni Service Area Including Exports.....................A-5-3 5.3.4 Constraints to Allocation of Santa Ana River Water.......................................A-5-3 5.3.4.1 Conveyance Routes Used for Captured SAR Water.......................A-5-3 5.3.4.2 Total Conveyance Capacity for Distributing Captured SAR Water..............................................................................................A-5-3 5.3.4.3 Conveyance Routes Used for Return of Exchange Water.............A-5-3 5.3.4.4 Available Absorptive Capacity and Demand Factors of Beneficial Uses.......................................................................................A-5-3 5.3.5 Constraints to Allocation of Water for Groundwater Recharge...................A-5-3 5.3.5.1 Defining Recharge Targets..................................................................A-5-3 5.3.6 Replenishment Obligations.................................................................................A-5-3 5.3.6.1 Background............................................................................................A-5-3 A-ii Santa Ana River Water Right Applications for Supplemental Water Supply Draft EIR October 2004 Appendix A - Surface Water Hydrology 5.3.6.2 Parameters Used in Calculating Replenishment Obligation.........A-5-3 5.3.6.3 Calculating Replenishment Obligation.............................................A-5-3 5.3.6.4 Availability of SWP Water...................................................................A-5-3 5.3.6.5 Relationship Between Replenishment Obligation and Recharge Target.....................................................................................A-5-3 5.3.6.6 Allocation of Replenishment Water...................................................A-5-3 5.4 Model Output......................................................................................................................A-5-3 5.5 Model Results.......................................................................................................................A-5-3 5.5.1 Deliveries of SAR Water to Beneficial Uses......................................................A-5-3 5.5.1.1 Initial Deliveries to Beneficial Uses....................................................A-5-3 5.5.1.2 Ultimate Deliveries to Beneficial Uses...............................................A-5-3 5.5.1.3 Ultimate Deliveries by Year................................................................A-5-3 5.5.2 Replenishment Obligations.................................................................................A-5-3 5.6 Sensitivity Analysis: Seasonal Water Conservation Storage.......................................A-5-3 5.7 Analysis of Maximum Daily Flow Events......................................................................A-5-3 6.0 RIVER ANALYSIS.........................................................................................................................A-6-3 6.1 Storm Flow Analysis...........................................................................................................A-6-3 6.1.1 General Description and Purpose of Storm Flow Analysis...........................A-6-3 6.1.2 HEC-RAS Model Structure..................................................................................A-6-3 6.1.3 Model Assumptions..............................................................................................A-6-3 6.1.4 HEC-RAS Model Input.........................................................................................A-6-3 6.1.5 HEC-RAS Model Results......................................................................................A-6-3 6.1.5.1 Verification of HEC-RAS Model Results..........................................A-6-3 6.2 Non-Storm Flow Analysis.................................................................................................A-6-3 6.2.1 DOP Input Parameters and Assumptions........................................................A-6-3 6.2.1.1 Assumptions..........................................................................................A-6-3 6.2.2 Daily River Analysis Model (DRAM)................................................................A-6-3 6.2.2.1 Input and Methodology.......................................................................A-6-3 6.2.3 Non-Storm Flow Analysis Results.....................................................................A-6-3 7.0 REFERENCES.................................................................................................................................A-7-3 8.0 ACRONYMS...................................................................................................................................A-7-3 LIST OF TABLES 2.2-1 Upper Santa Ana River Median, Maximum, and Minimum Annual Flow.............A-2-3 2.2-2 Tributary Flow Contribution to the Santa Ana River (100-year flood event discharge in cfs)...................................................................................................................A-2-3 2.2-3 Treated Wastewater Discharged Directly to the Santa Ana River above Riverside Narrows..............................................................................................................A-2-3 2.2-4 Estimated Historic Flows on the Santa Ana River Downstream of the Santa Ana River – Mill Creek Confluence......................................................................A-2-3 2.2-5 Santa Ana River Mainstem Discharge-Frequency Values under Pre- and Post-Seven Oaks Dam........................................................................................................A-2-3 Santa Ana River Water Right Applications for Supplemental Water Supply Draft EIR A-iii October 2004 Appendix A - Surface Water Hydrology 2.2-6 Discharge, Depth and Velocity for Pre- and Post-Seven Oaks Dam Conditions, 50- and 100-Year Flood Events..................................................................A-2-3 2.2-7 Tributaries Contributing Sediment to the SAR..............................................................A-2-3 2.3-1 Beneficial Uses of Santa Ana River Water......................................................................A-2-3 2.3-2 Santa Ana River Basin Surface Water Quality Objectives..........................................A-2-3 2.3-3 Average Historic Surface Water Quality for Locations on the Santa Ana River (1990-2001)..............................................................................................A-2-3 3.4-1 Potential Base Periods........................................................................................................A-3-3 4.2-1 Water Uses in OPMODEL.................................................................................................A-4-3 4.2-2 Average Net Evaporation Rates (inches per month)....................................................A-4-3 4.2-3 Seven Oaks Dam End-of-Month Target Storage (in af)................................................A-4-3 4.2-4 Scenarios for Analysis.......................................................................................................A-4-3 4.2-5 Estimates of Unappropriated SAR Water Available for Capture by Muni/Western for Base Period WY 1961-62 through WY 1999-2000 (1,500 cfs Diversion Rate)....................................................................................................................A-4-3 4.2-6 Estimates of Unappropriated SAR Water Available for Capture by Muni/Western for Base Period WY 1961-62 through WY 1999-2000 (500 cfs Diversion Rate)....................................................................................................................A-4-3 4.2-7 Estimated Muni/Western Diversions for No Project and Scenarios B and D.........A-4-3 4.2-8 Estimated Muni/Western Diversions for No Project, and Scenarios A and C........A-4-3 5.3-1 Characteristics of Beneficial Uses within Allocation Model........................................A-5-3 5.3-2 Existing and Future Demands and Water Supplies for Purveyors of the Muni Service Area...............................................................................................................A-5-3 6.1-1 Pre-Dam and Post-Dam Peak Discharges and Areas Flooded Downstream of the SAR and Mill Creek Confluence...........................................................................A-6-3 6.1-2 Description of Reaches of SAR by River Mile Stationing............................................A-6-3 6.1-3 Effects of Muni/Western Diversion of up to 1,500 cfs in Sub-Area 2........................A-6-3 6.1-4 Effects of Muni/Western Diversion of up to 1,500 cfs in Sub-Area 3.......................A-6-3 6.1-5 Verification of HEC-RAS 3.1.1 Model for Sub-Area 2..................................................A-6-3 6.1-6 Verification of HEC-RAS 3.1.1 Model for Sub-Area 3..................................................A-6-3 6.2-1 Project Effect on Non-Storm Days above Cuttle Weir – Monthly Summary for WY 1966-67 through WY 1999-2000..........................................................................A-6-3 6.2-2 Project Effect on Non-Storm Days Downstream from Cuttle Weir – Monthly Summary for WY 1966-67 through WY 1999-2000........................................................A-6-3 6.2-3 Project Effect on Non-Storm Days at Mill Creek Confluence – Monthly Summary for WY 1966-67 through WY 1998-99............................................................A-6-3 6.2-4 Project Effect on Non-Storm Days at “E” Street – Monthly Summary for WY 1966-67 through WY 1999-2000.................................................................................A-6-3 6.2-5 Project Effect on Non-Storm Days at RIX and Rialto Effluent Outfall – Monthly Summary for WY 1966-67 through WY 1999-2000.......................................A-6-3 6.2-6 Project Effect on Non-Storm Days at Riverside Narrows – Monthly Summary for WY 1969-70 through WY 1999-2000........................................................A-6-3 6.2-7 Summary Results of Zero-Flow Day Analysis (WY 1966-67 to WY 1999-2000)......A-6-3 A-iv Santa Ana River Water Right Applications for Supplemental Water Supply Draft EIR October 2004 Appendix A - Surface Water Hydrology LIST OF FIGURES 1 All figures can be found in sequential order at the end of the chapter in which they are first referenced. 2 CHAPTER 1.0 FIGURES 1-1 Modeling Tools Used in Hydrologic Analyses 3 CHAPTER 2.0 FIGURES 2.1-1 Santa Ana River Watershed, Gaging Stations, and Muni/Western Service Areas 2.2-1 Schematic of Water Control Features and Gages in the Santa Ana River Canyon 2.2-2 Annual Flows at the River Only Mentone, “E” Street, and MWD Crossing Gages 2.2-3 Probability of Annual Flow at the River Only Mentone, “E” Street, and MWD Crossing Gages 2.2-4 Variability in Monthly Flow, Santa Ana River at River Only Mentone Gage 2.2-5 Probability of Monthly Flow at the River Only Mentone Gage, Months of October, November, and December (WY 1911-12 to WY 1999-2000) 2.2-6 Probability of Monthly Flow at the River Only Mentone Gage, Months of January, February, and March (WY 1911-12 to WY 1999-2000) 2.2-7 Probability of Monthly Flow at the River Only Mentone Gage, Months of April, May, and June (WY 1911-12 to WY 1999-2000) 2.2-8 Probability of Monthly Flow at the River Only Mentone Gage, Months of July, August, and September (WY 1911-12 to WY 1999-00) 2.2-9 Wastewater Discharges to Santa Ana River above Riverside Narrows, WY 1970-71 through WY 2000-01 2.2-10 Seven Oaks Reservoir Levels 2.3-1 Santa Ana River, Tributaries, and Segment Indicators 2.4-1 San Bernardino Valley Water Conservation District Annual Santa Ana River Diversions, WY 1914-15 through 1998-99 2.5-1 Southern California Edison Company Canal USGS Gaging Station 11049500, WY 1914-15 through WY 1998-99 2.5-2 Probability of Daily Discharge for SAR Segment B, above Cuttle Weir, WY 1966-67 through WY 1999-2000 2.5-3 Probability of Daily Discharge for SAR Segment C, below Cuttle Weir, WY 1966-67 through WY 1999-2000 2.5-4 Probability of Daily Discharge for SAR Segment D, below Mill Creek, WY 1966-67 through WY 1999-2000 2.5-5 Probability of Daily Discharge for SAR Segment E, below “E” Street, WY 1966-67 through WY 1999-2000 2.5-6 Probability of Daily Discharge for SAR Segment F, below RIX and Rialto Effluent Outfall, WY 1966-67 through WY 1999-2000 Santa Ana River Water Right Applications for Supplemental Water Supply Draft EIR A-v October 2004 Appendix A - Surface Water Hydrology CHAPTER 3.0 FIGURES 3.2-1 Accumulated Departure from the Average Annual Precipitation at San Bernardino County Hospital Recording Station for WY 1883-84 through WY 2001-02 3.2-2 Accumulated Departure from the Average Annual Runoff at Combined Flow Mentone Gage for WY 1913-14 to WY 2000-01 CHAPTER 4.0 FIGURES 4.2-1 OPMODEL Structure 4.2-2 Cumulative Diversions by Senior Water Rights Claimants from the Santa Ana River WY 1961-62 through WY 1999-2000. 4.2-3 Cumulative Diversions by the Conservation District from the Santa Ana River WY 1961-62 through WY 1999-2000. CHAPTER 5.0 FIGURES 5.2-1 Allocation Model Structure 5.3-1 Potential Conveyance Routes for Santa Ana River Water 5.3-2 Potential Conveyance Routes for Return of SAR Exchange Water 5.5-1 Projected Median Annual Initial Delivery of Captured SAR Water by Priority 5.5-2 Projected Maximum Annual Initial Delivery of Captured SAR Water by Priority 5.5-3 Projected Cumulative Total Initial Delivery of Captured SAR Water by Priority 5.5-4 Projected Annual Initial Deliveries of Captured SAR Water to Specific Beneficial Uses, Scenario A 5.5-5 Projected Annual Initial Deliveries of Captured SAR Water to Specific Beneficial Uses, Scenario B 5.5-6 Projected Annual Initial Deliveries of Captured SAR Water to Specific Beneficial Uses, Scenario C 5.5-7 Projected Annual Initial Deliveries of Captured SAR Water to Specific Beneficial Uses, Scenario D 5.5-8 Projected Initial Annual Delivery of Captured SAR Water by Priority, Scenario A 5.5-9 Projected Initial Annual Delivery of Captured SAR Water by Priority, Scenario B 5.5-10 Projected Initial Annual Delivery of Captured SAR Water by Priority, Scenario C 5.5-11 Projected Initial Annual Delivery of Captured SAR Water by Priority, Scenario D 5.5-12 Projected Median Annual Ultimate Delivery of Captured SAR Water by Priority 5.5-13 Projected Ultimate Delivery of Captured SAR Water by Specific Beneficial Use, Scenario A 5.5-14 Projected Ultimate Delivery of Captured SAR Water by Specific Beneficial Use, Scenario B A-vi Santa Ana River Water Right Applications for Supplemental Water Supply Draft EIR October 2004 Appendix A - Surface Water Hydrology 5.5-15 Projected Ultimate Delivery of Captured SAR Water by Specific Beneficial Use, Scenario C 5.5-16 Projected Ultimate Delivery of Captured SAR Water by Specific Beneficial Use, Scenario D 5.5-17 Projected Ultimate Delivery of Captured SAR Water by Priority, Scenario A 5.5-18 Projected Ultimate Delivery of Captured SAR Water by Priority, Scenario B 5.5-19 Comparison of Initial and Ultimate Deliveries, Scenario A 5.5-20 Comparison of Initial and Ultimate Deliveries, Scenario B 5.5-21 Projected Ultimate Delivery of Captured SAR Water by Priority, Scenario C 5.5-22 Projected Ultimate Delivery of Captured SAR Water by Priority, Scenario D 5.5-23 Comparison of Initial and Ultimate Deliveries, Scenario C 5.5-24 Comparison of Initial and Ultimate Deliveries, Scenario D 5.5-25 Projected Ultimate Delivery of Captured SAR Water by Priority (Cumulative Total) 5.5-26 Projected Sources of Water Used to Meet Replenishment Obligations of the SBBA 5.5-27 Projected Use of Muni’s Available SWP Table A Water within Muni’s Service Area CHAPTER 6.0 FIGURES 6.1-1 River Analysis (Peak Flow, Channel Velocity, Depth, and Overbank Flow) 6.2-1 Daily River Analysis Model (DRAM) Structure 6.2-2 Median Monthly Flows (Non-Storm Days) for SAR Sebment B, just above Cuttle Weir, WY 1966-67 through WY 1999-2000 6.2-3 Median Monthly Flows (Non-Storm Days) for SAR Segment C, below Cuttle Weir, WY 1966-67 through WY 1999-2000 6.2-4 Median Monthly Flows (Non-Storm Days) for SAR Segment D, below Mill Creek Confluence, WY 1966-67 through WY 1998-99 6.2-5 Median Monthly Flows (Non-Storm Days) for SAR Segment E, below “E” Street, WY 1966-67 through WY 1999-2000 6.2-6 Median Monthly Flows (Non-Storm Days) for SAR Segment F, below RIX and Rialto Effluent Outfall, WY 1966-67 through WY 1999-2000 6.2-7 Median Monthly Flows (Non-Storm Days) for SAR Segment G, at Riverside Narrows, WY 1969-70 through WY 1999-2000 6.2-8 Probability of Daily Discharge (Non-Storm Days) for SAR Segment B, above Cuttle Weir, WY 1966-67 through WY 1999-2000 6.2-9 Probability of Daily Discharge (Non-Storm Days) for SAR Segment C, below Cuttle Weir, WY 1966-67 through WY 1999-2000 6.2-10 Probability of Daily Discharge (Non-Storm Days) for SAR Segment D, below Mill Creek Confluence, WY 1966-67 through WY 1998-99 6.2-11 Probability of Daily Discharge (Non-Storm Days) for SAR Segment E, below “E” Street, WY 1966-67 through WY 1999-2000 Santa Ana River Water Right Applications for Supplemental Water Supply Draft EIR A-vii October 2004 Appendix A - Surface Water Hydrology 6.2-12 Probability of Daily Discharge (Non-Storm Days) for SAR Segment F, below RIX and Rialto Outfall, WY 1966-67 through WY 1999-2000 6.2-13 Probability of Daily Discharge (Non-Storm Days) for SAR Segment G, below Riverside Narrows Outfall, WY 1969-70 through WY 1999-2000 A-viii Santa Ana River Water Right Applications for Supplemental Water Supply Draft EIR October 2004 1 1.0 INTRODUCTION 2 This Surface Water Hydrology appendix contains background information that supports the 3 impact analyses in the Environmental Impact Report (EIR). The effects identified through these 4 analyses also influence groundwater characteristics such as depth to groundwater, interaction 5 with contaminant plumes, and water quality. Such potential interactions are addressed in 6 Appendix B - Groundwater Hydrology. 7 Chapter 2, Santa Ana River System, presents a description of existing and future conditions in the 8 upper SAR basin. The conditions described include the following: 9 • Hydrologic characteristics of the SAR and its tributaries; 10 • Effects on the flow regime of the SAR attributable to construction and operation of 11 Seven Oaks Dam; 12 • Major structures on the mainstem of the SAR such as dams and water diversion 13 structures; 14 • Water rights and water diversions; and 15 • Water quality conditions and objectives. 16 Chapter 3, Hydrologic Base Period Determination, describes the selection of the base period used 17 in the surface water and groundwater hydrologic modeling for the Project. 18 Chapter 4, Operations Model (OPMODEL), describes the model developed to estimate the 19 quantity of unappropriated SAR water available for diversion by Muni/Western. This model 20 simulates monthly releases that could be made from Seven Oaks Dam under a set of variable 21 conditions. These conditions are determined by a number of parameters including the following: 22 • Diversions by senior water rights claimants; 23 • Diversions by the San Bernardino Valley Water Conservation District 24 (Conservation District); 25 • Releases designed to accomplish habitat restoration as prescribed by the terms of the 26 Biological Opinion (BO) of the U.S. Fish and Wildlife Service for operation of 27 Seven Oaks Dam; and 28 • Operation of Seven Oaks Dam for either flood control or a combination of flood control 29 and seasonal storage. 30 Chapter 5, Allocation Model, describes the approach taken to simulate the manner in which water 31 diverted by Muni/Western would be put to beneficial use. The Allocation Model is a mechanism 32 designed to distribute the diverted water through a set of existing and proposed conveyance 33 facilities to a set of water uses. These uses are: 34 • Direct use in the Muni/Western service areas; 35 • Groundwater recharge of the San Bernardino Basin Area (SBBA); Santa Ana River Water Right Applications for Supplemental Water Supply Draft EIR A-1-1 October 2004