,...... ~ . Mojave Water Agency i BOOkman-_ Edmonston _ A DIVISion of GEl Consultants Geotechnical December 16, 2005 Environmental and 042180 \X!ater Resources Engineering Mr. Norman T. Caouette Assistant General Manager Mojave Water Agency 22450 Headquarters Drive Apple Valley, CA 92307-4304 Subject: Technical Study to Evaluate a Potential Long-Term Water Management Program Between the Mojave Water Agency and Metropolitan Water Storage District Dear Mr. Caouette: Bookman-Edmonston a division of GEl Consultants in association with Science Applications International Corporation is pleased to submit our report entitled "Technical Study to Evaluate a Potential Long-Term Water Management Program Between the Mojave Water Agency and Metropolitan Water Storage District." We are prepared to present the findings ofthis report to the local community or other parties. We are also available to provide any further technical support, including evaluation ofadditional scenarios or response to comments. It has been our privilege to provide this service to Mojave Water Agency and to Metropolitan Water District. Sincerely, Richard A. Rhone, P.E. Managing Executive Engineer Enclosures cc: Robert Beeby, SAlC ww,v.ge ico nsul [<1 n [S.COIl1 GEl Consultants, Inc. 225 West Broadway, Suite 400, Glendale, California 91204-1331 818.244.0117 fax: 818.242.0480 Technical Study to Evaluate a Potential Long-Term Water Management Program Between The Mojave Water Agency and Metropolitan Water District Date: December 2005 Project No: 042810 in association with Table of Contents Introduction v Organization of Report vi Executive Summary 1 Program Alternatives 1 The Recommended MWA/Metropolitan Program 2 Cost Sharing Opportunities 4 Program Cost Summary 5 1.0 Existing Water Management Program and Initial Screening of Alternatives 6 1.1 Current MWA Operations 6 1.1.1 Current Water Management Principals 6 1.1.2 Land Use and Water Requirements 6 1.2 Water Supplies 7 1.2.1 Surface Water 7 1.3 Groundwater 8 1.4 Geology 9 1.5 Hydrogeology 10 1.6 Groundwater Quality 10 1.7 Existing Facilities 11 1.7.1 State Water Project 11 1.7.2 MWA Facilities 11 1.7.3 Local Water Purveyors 12 1.7.4 Demonstration Banking Report 13 1.8 MWA/Metropolitan Water Management Program 14 1.8.1 Storage of Supplemental Water 14 1.8.2 Recovery of Stored Water 14 1.9 Screening Matrix 15 1.10 Criteria and Assumptions 15 1.11 Alternatives 17 1.11.1 Multipurpose Opportunity Alternatives 17 1.11.2 Water Transfer and Storage Alternatives 18 1.11.3 Recovery Operations 19 1.12 Conclusion and Recommendations 19 2.0 Preliminary Engineering and Hydrogeology Review for Put Alternatives 22 2.1 Summary of Put Alternatives 22 2.2 Description of Put Alternatives 25 2.2.1 Alternative P1 – Mojave River Dam Storage 26 2.2.2 Alternative P2 – Mojave River via Cedar Springs Dam 26 2.2.3 Alternative P3A – Alto Subarea via Mojave River Pipeline and East Branch 27 2.2.4 Alternative P4A and P4B – Alto Subarea via Morongo Basin Pipeline 28 2.2.5 Alternative P5 – In-Lieu Recharge via Water Treatment Plant 29 2.2.6 Alternative P7 – Oeste Spreading Along East Branch 29 2.2.7 Alternative P8 – Alto Spreading Along East Branch and in Oro Grande and Antelope Valley Washes 30 2.2.8 Alternative P9 – Upper Mojave River via East Branch through Unnamed Wash 31 2.3 Hydrogeology Review of Put Alternatives 32 2.3.1 Alternatives P7 and P8 - Close to the East Branch 33 2.3.2 Antelope Wash 35 2.3.3 Alternatives P3 and P4 – Along the Mojave and Morongo Basin Pipelines 35 2.3.4 Alternatives P1, P2, and P9 – Mojave River Recharge Alternatives 37 2.4 Screening of Put Alternatives 38 2.5 Cost Assessment of Put Alternatives 38 2.5.1 Alternative P2 – Mojave River via Cedar Springs Dam 41 2.5.2 Alternative P3A – Alto Subarea via Mojave River Pipeline and East Branch 41 2.5.3 Alternatives P4A and P4B – Alto Subarea via Morongo Basin Pipeline 42 2.5.4 Alternative P5 – In Lieu Recharge via Water Treatment Plant 42 2.5.5 Alternative P7 – Oeste Spreading Along the East Branch 43 2.5.6 Alternative P8 – Alto Spreading Along East Branch and in Oro Grande and Antelope Valley Washes 43 2.5.7 Alternative P9 – Upper Mojave River via East Branch through Unnamed Wash 44 2.6 Ranking of Alternatives 44 2.7 Conclusions and Recommendations 46 3.0 Metropolitan Water Storage Assessment 48 3.1 Activities Relating to Storage Options 48 3.2 Metropolitan’s Water Supply 49 3.3 Metropolitan’s Storage Programs 50 3.3.1 Coachella Valley Water District and Desert Water Agency 51 3.3.2 Semitropic Water Storage District 51 3.3.3 Arvin-Edison Water Storage District 53 3.4 Metropolitan’s Range of Storage Programs with Mojave Water Agency 54 3.5 Program Flexibility 54 3.6 Conclusion 54 4.0 Preliminary Engineering for Take Alternatives 56 4.1 Effect of Entitlement Exchange on Return Scenarios 57 4.2 Description of Take Alternatives 58 4.2.1 Alternative T0 – Direct Return Through Regional Sub-Projects from Alto Subarea 58 Bookman-Edmonston, a division of GEI Consultants, Inc. ii 4.2.2 Alternative T1 – Direct Return through the Mojave River Pipeline from Alto Subarea 59 4.2.3 Alternative T2 – Direct Return through the Morongo Basin Pipeline from Alto Subarea 60 4.2.4 Alternative T3 – Direct Return from the Floodplain Aquifer 61 4.2.5 Alternative T4 – Direct Return from Oeste Subarea 61 4.2.6 Alternative T5 – Entitlement Exchange Alternative 62 4.2.6.1 Environmental Considerations 63 4.2.6.2 Other Considerations 63 4.3 Hydrogeology Review of Take Alternatives 63 4.4 Fatal Flaw Screening of Take Alternatives 64 4.5 Cost Assessment of Take Alternatives 64 4.5.1 Alternative T1 – Direct Return Through Mojave River Pipeline from Alto Subarea 64 4.5.2 Alternative T2 – Direct Return Through Morongo Basin Pipeline 65 4.5.3 Alternative T3 – Direct Return from Floodplain Aquifer (in combination with Alternative T0) 66 4.5.4 Alternative T4 - Direct Return from Oeste Subarea 67 4.5.5 Alternative T5 – Entitlement Exchange Alternatives 68 4.6 Ranking of Alternatives 68 4.7 Conclusions and Recommendations 69 5.0 Local Water Agency Participation 71 5.1 Potential Benefits for Participating Local Agencies 71 5.2 Screening of Local Agencies 72 5.2.1 Proximity to the East Branch 73 5.2.2 Existing Production Data 73 5.2.3 Projected Growth and Future Production 73 5.3 Selection of Local Water Agencies 73 5.4 Existing and Potential Facilities of Interested Local Agencies 74 5.4.1 Victor Valley Water District 75 5.4.1.1 Proposed Facilities 76 5.4.2 Baldy Mesa Water District 77 5.4.2.1 Proposed Facilities 77 5.4.3 Hesperia Water District 78 5.4.3.1 Proposed Facilities 78 5.4.4 San Bernardino County Special District 70L and 70J 79 5.4.4.1 Proposed Facilities 80 5.5 Integration of Local Agency Information 80 5.5.1 Potential Local Agency Involvement in MWA/Metropolitan Program 82 5.6 Potential Mitigation Planning for Alternatives 82 5.7 Conclusion and Recommendations 83 6.0 Institutional Issues Screening of Alternatives 88 6.1 Overview of Institutional Issues 88 6.1.1 Adjudicated Groundwater Basins 88 Bookman-Edmonston, a division of GEI Consultants, Inc. iii 6.1.2 Conjunctive Use Agreement 89 6.1.3 Use of State Water Project Supplies and Facilities 90 6.1.4 Other Agreements 91 6.2 Issues with Existing Groundwater Banks 93 6.3 Screening of Alternatives by Institutional Issues 95 7.0 Facilities Cost Estimate 97 7.1 Formulation of Possible MWA/Metropolitan Program Matrix 97 7.1.1 Mutual Exchange Program 98 7.2 Sizing the MWA/Metropolitan Program 99 7.2.1 Facility Composition with Entitlement Exchange 101 7.3 Program Facilities 103 7.4 Cost Evaluations 106 7.4.1 Annual Cost Evaluations 107 7.5 Project Flexibility 108 7.6 Conclusion 108 Appendices A Local Model Simulating River Recharge and Pumping Scenarios B Cost Estimates Bookman-Edmonston, a division of GEI Consultants, Inc. iv Introduction The MWA is a regional water management entity created by special act of the California legislature. It is one of the 29 contractors with the California Department of Water Resources (DWR) and has a contract for up to 75,800 acre-feet of water from the State Water Project (Table A entitlement). The MWA encompasses over 4,900 square miles within the High Desert Region of San Bernardino County in southern California and contains several distinct groundwater basins and subareas. Plate1 illustrates the MWA area. Two of those basins, Mojave Area Basin including its five subareas, and the Warren Valley Basin which is a subarea of the Morongo Basin/Johnson Valley Basin, have been adjudicated because of the long-term overdraft of groundwater for agricultural, municipal, and industrial water supplies. The region has historically imported a negligible amount of SWP water and has been dependent upon its groundwater supply, the region has experienced cumulative groundwater overdraft since the early 1950s. Groundwater has been the primary source of water for the MWA. Consequently, MWA programs have focused on ways to increase the availability and reliability of the local water supply through the continued review and improvement of its management of groundwater resources. MWA recognizes that years of cumulative overdraft have increased the available groundwater storage. This presents an opportunity for enhanced conjunctive management of groundwater and surface water resources, both local and imported.