2020 UPPER SANTA ANA RIVER WATERSHED INTEGRATED REGIONAL URBAN WATER MANAGEMENT PLAN 2020 IRUWMP EXECUTIVE SUMMARY 1 UPPER SANTA ANA RIVER WATERSHED 2020 IRUWMP – Public Review Draft Regional Context JUNE 2021 Prepared by Water Systems Consulting, Inc. and Woodard & Curran TABLE OF CONTENTS 1. Introduction ................................................................................................................................................1-1 1.1 Background and Purpose ................................................................................................................1-3 1.1.1 IRWM Plan ................................................................................................................................1-3 1.1.2 Regional UWMP ......................................................................................................................1-4 1.1.3 2020 Integrated Regional Urban Water Management Plan .........................................1-5 1.2 Plan Organization ............................................................................................................................1-7 1.3 Regional Governance and Stakeholder Involvement .................................................................1-8 1.3.1 Regional Water Management Group .................................................................................1-8 1.3.2 Governance Structure .............................................................................................................1-9 1.3.3 Stakeholder Identification and Involvement ........................................................................1-9 1.3.4 Disadvantaged Community and Tribal Outreach ........................................................... 1-10 1.4 Plan Preparation Process .............................................................................................................. 1-11 1.4.1 Public Participation ............................................................................................................... 1-11 1.4.2 Stakeholder Workshops ...................................................................................................... 1-11 1.4.3 Planning, Reports and Technical Analyses ........................................................................ 1-13 1.5 Plan Adoption ................................................................................................................................. 1-14 1.6 Relation to Other Efforts ............................................................................................................... 1-15 1.6.1 Coordination with Neighboring IRWM Regions and IRWM Planning ......................... 1-15 1.6.2 IRUWMP Relation to Local Water Planning and Land Use Planning .......................... 1-17 2. Region Description ...................................................................................................................................2-1 2.1 Location ...............................................................................................................................................2-2 2.2 Water Agencies in the Region ........................................................................................................2-2 2.2.1 Water Supply Managers, Wholesalers and Retailers .....................................................2-5 2.2.2 Flood Control Agencies ........................................................................................................ 2-15 2.2.3 Other Water Related Entities ............................................................................................. 2-16 2.3 Population and Demographics .................................................................................................... 2-17 2.3.1 Historic Population and Housing Growth in the Plan Area ............................................ 2-17 2.3.2 Future Population Projections in the Plan Area ................................................................ 2-17 2.3.3 Economic Condition and Social and Cultural Composition of the Region ................... 2-19 2.4 Land Uses ........................................................................................................................................ 2-21 2.5 Ecological and Environmental Resources .................................................................................... 2-24 Upper Santa Ana River Watershed i 2020 IRUWMP – Public Review Draft Table of Contents 2.5.1 SAR Corridor .......................................................................................................................... 2-24 2.5.2 San Bernardino National Forest ......................................................................................... 2-26 2.5.3 U.S. Bureau of Land Management Area of Critical Environmental Concern ............. 2-27 2.5.4 U.S. Army Corps of Engineers Woolly-Star Preserve Area .......................................... 2-28 2.5.5 Western Riverside County Multi-Species Habitat Conservation Plan ......................... 2-28 2.5.6 Upper Santa Ana River Habitat Conservation Plan ....................................................... 2-29 2.5.7 Wash Plan Habitat Conservation Plan ............................................................................. 2-29 2.5.8 Unarmored Threespine Stickleback Shay Pond Fish Refugium ..................................... 2-30 2.6 Regional Climate ............................................................................................................................ 2-31 2.6.1 Current Regional Climate .................................................................................................... 2-31 2.6.2 Potential Effects of Climate Change ................................................................................. 2-33 3. Regional Water Sources and Management .......................................................................................3-1 3.1 Surface Hydrology ...........................................................................................................................3-2 3.1.1 SAR Reaches .............................................................................................................................3-2 3.1.2 Natural Runoff ..........................................................................................................................3-3 3.2 Imported Water ................................................................................................................................3-7 3.2.1 SWP Overview .........................................................................................................................3-7 3.2.2 Imported Water Supply Reliability ................................................................................... 3-11 3.2.3 Valley District SWP Supply Reliability (Review)............................................................. 3-13 3.3 Groundwater .................................................................................................................................. 3-18 3.3.1 San Bernardino Basin ........................................................................................................... 3-20 3.3.2 Rialto-Colton Sub basin ....................................................................................................... 3-21 3.3.3 Riverside-Arlington Sub-basin ............................................................................................ 3-25 3.3.4 Yucaipa Sub basin ................................................................................................................ 3-26 3.3.5 San Timoteo Sub basin ......................................................................................................... 3-27 3.3.6 Chino Sub basin ..................................................................................................................... 3-28 3.3.7 Bear Valley Basin ................................................................................................................. 3-29 3.3.8 Recharge Area Programs .................................................................................................... 3-30 3.4 Recycled Water ............................................................................................................................. 3-33 3.5 Transfers, Exchanges, and Groundwater Banking Programs ................................................ 3-43 3.5.1 Transfers and Exchanges ..................................................................................................... 3-43 3.5.2 Groundwater Banking Programs ....................................................................................... 3-43 3.6 Planned Water Supply Projects and Programs ....................................................................... 3-44 3.6.1 Recycled Water .................................................................................................................... 3-44 3.6.2 Conjunctive Use Projects ...................................................................................................... 3-44 3.6.3 Groundwater Recharge ....................................................................................................... 3-45 Upper Santa Ana River Watershed ii 2020 IRUWMP – Public Review Draft Table of Contents 3.7 Development of Desalination ....................................................................................................... 3-50 3.7.1 Opportunities for Brackish Water and/or Groundwater Desalination