FORTY-SECOND ANNUAL ENGINEERING AND SURVEY REPORT ON WATER SUPPLY CONDITIONS OF THE SANTA YNEZ RIVER WATER CONSERVATION DISTRICT 2019-2020 April 24, 2020 Northern California Southern California Arizona Colorado Oregon FORTY-SECOND ANNUAL ENGINEERING AND SURVEY REPORT ON WATER SUPPLY CONDITIONS OF THE SANTA YNEZ RIVER WATER CONSERVATION DISTRICT 2019-2020 April 24, 2020 CARLSBAD, COVINA, AND SAN RAFAEL, CALIFORNIA APACHE JUNCTION, ARIZONA CENTENNIAL, COLORADO MEDFORD, OREGON 1126-13 April 24, 2020 San Rafael Board of Directors Santa Ynez River Water Conservation District P.O. Box 719 Santa Ynez, California 93460 Re: Forty-Second Annual Engineering Survey and Report on Water Supply Conditions of the Santa Ynez River Water Conservation District, 2019-2020 Dear Board Members: Transmitted herewith is our Engineering Survey and Report on Water Supply Conditions of the Santa Ynez River Water Conservation District for 2019-2020. This, the Forty-Second Annual Report, presents the required and pertinent information for the Board of Directors to make necessary determinations for levying groundwater charges upon the production of groundwater from water-producing facilities (water wells) within the District. As such, it provides information on the status of the groundwater and surface water supplies, as well as the annual production of groundwater from within the District. Sincerely, Oliver S. Page OSP:rrk Enclosures TABLES OF CONTENTS Page Number 1.0 Introduction 1 1.1. Historical Background 1 1.2. Description of the District 2 1.3. Report Summary 3 1.4. Findings and Determinations 7 1.5. Sources of Information 8 2.0 Groundwater Charges 9 2.1. Revenues 10 2.2. Groundwater Production 10 2.3. Well Registration 12 2.4. Major Producers 12 3.0 Precipitation 18 4.0 Surface Water Conditions 21 4.1. Basin Surface Water Use 21 4.2. State Water Project Water Use 24 4.3. River System Flow Conditions 25 4.4. Water Rights Releases 25 4.5. State Water Code Requirements 30 5.0 Groundwater Conditions 31 5.1. Sources of Groundwater 31 5.2. Groundwater Level Changes 32 5.3. Storage Changes 37 5.4. Change in Storage Trends 45 5.5. Safe Yield 45 5.6. Historical Pumpage 45 5.7. Overdraft 45 5.8. Groundwater Quality 50 APPENDICES A Summary of Provisions in the California Water Code Pertaining to the Implementation of a Groundwater Charge B Historical Groundwater Charge Rates C Additional Streamflow Records, Santa Ynez River Basin D Water Rights Releases – No release in 2019 E General Description of the Hydrogeology of the Sources of Groundwater within the District F Water-Level Hydrographs of Selected Wells G Well Inventory i LIST OF TABLES Page Number Table 1a Annual Reported Groundwater Production Within the District, All District Zones .................................................................................................. 13 Table 1b Annual Reported Groundwater Production Within the District Agricultutal Water ................................................................................................ 14 Table 1c Annual Reported Groundwater Production Within the District Other Water ........................................................................................................... 15 Table 1d Annual Reported Groundwater Production Within the District Special Irrigation Water ........................................................................................ 16 Table 2 Monthly Precipitation and Departure From Normal at Bradbury Dam and Lompoc January 2019 through March 2020 ......................................................... 20 Table 3 Summary of Cachuma Project Operations 1953 Through 2019 ........................... 22 Table 4 Flow of the Santa Ynez River at the Lompoc Narrows ........................................ 26 Table 5 Flow of Salsipuedes Creek Near Lompoc ............................................................ 27 Table 6 Historical Water Rights Releases.......................................................................... 29 Table 7 Water-Level Changes Lompoc Plain Subarea 2019 to 2020 ................................ 33 Table 8 Water-Level Changes Lompoc Upland and Lompoc Terrace Subareas 2019 to 2020 ......................................................................................................... 34 Table 9 Water-Level Changes Santa Rita and Buellton Upland Subareas 2019 to 2020 .. 34 Table 10 Water-Level Changes Santa Ynez Upland Subarea 2019 to 2020 ....................... 35 Table 11 Estimated Annual Change of Groundwater in Storage in the Santa Ynez River Alluvium for the Past Ten Years and Current Year (2019-20) ............................. 38 Table 12 Estimated Annual Change of Groundwater in Storage in the Lompoc Plain Subarea for the Past Ten Years and Current Year (2019-20) ............................... 39 Table 13 Estimated Annual Change of Groundwater in Storage in the Lompoc Upland and Lompoc Terrace Subareas for the Past Ten Years and Current Year (2019-20)............................................................................................................... 41 Table 14 Estimated Annual Change of Groundwater in Storage in the Santa Rita Upland Subarea For the Past Ten Years and Current Year (2019-20) .............................. 42 Table 15 Estimated Annual Change of Groundwater in Storage in the Eastern Portion of the Buellton Upland Subarea For the Past Ten Years and Current Year (2019-20)............................................................................................................... 43 Table 16 Estimated Annual Change of Groundwater in Storage in the District Portion of the Santa Ynez Upland Subarea For the Past Ten Years and Current Year (2019-20)............................................................................................................... 44 Table 17 Summary of Change in Quantity of Groundwater in Storage Within the District................................................................................................................... 46 ii Table 18 Estimated Average Safe Yield of Principal Sources of Groundwater Within the District ............................................................................................................. 47 Table 19 Estimated Average Annual Historical Reported Groundwater Pumpage from the Principal Sources of Groundwater Within the District .......................... 48 Table 20 Average Annual Overdraft of Principal Sources of Groundwater Within the District................................................................................................................... 49 Table 21 Estimated Accumulated Overdraft of Principal Sources of Groundwater Within the District................................................................................................. 51 LIST OF FIGURES Following Page No. 1 Santa Ynez River Water Conservation District 4 2 Groundwater Charge Zones, Santa Ynez River Water Conservation District 10 3 Annual Groundwater Production Within the District, 5-Year Moving Average 18 4 Annual Precipitation and Cumulative Departure from Mean for Lompoc, Santa Barbara, Bradbury Dam, and Gibraltar Dam 20 5 Monthly Surface Flow, Santa Ynez River Near Lompoc 26 6 Major Groundwater Sources, Santa Ynez River Basin 32 7 Accumulated Dewatered Storage 46 8 Graphs Showing Total Dissolved Solids, Chloride and Sodium Concentrations in Groundwater from Selected Wells Located in the Lompoc Plain Subarea 52 LIST OF TERMS Accumulated Overdraft ..........The amount of water necessary to be replaced in the intake areas of the groundwater basins within the District or any zone or zones thereof to prevent the landward movement of salt water into the fresh groundwater body, or to prevent subsidence of the land within the District or any zone or zones thereof, as determined by the board from time to time. Defined in Water Code Section 75505. See also Dewatered Storage Acre-Foot ...............................Volume of water to flood one acre to a depth of one foot (325,851 gallons). Ad Valorem property tax .......Property tax assessed according to value of property. AF, AC-FT .............................Acre-Foot. iii Agricultural water ..................Produced water first used on lands in the production of plant crops or livestock for market. Defined in Water Code Section 75508. Alluvium ................................Sediments deposited through stream or river action. In Santa Ynez these sediments are generally much younger, less consolidated, with greater hydraulic conductivity, than the surrounding marine and non-marine sediments. ANA .......................................Above Narrows Account. Water rights release from Bradbury Dam (Lake Cachuma) made to replenish the groundwater basin upstream of the Lompoc Narrows area. Annual Overdraft ...................The amount, determined by the board, by which the production of water from groundwater supplies within the District or any zone or zones thereof during the water year exceeds the natural replenishment of such groundwater supplies in such water year. Defined in Water Code Section 75506. BNA .......................................Below Narrows Account. Water rights release from Bradbury Dam (Lake Cachuma) made to replenish the groundwater basin downstream of the Lompoc Narrows area, i.e. for the Lompoc Plain subarea. Board .....................................Refers to the five Directors of the Santa Ynez River Water Conservation District. Bradbury Dam .......................Completed in 1953, the dam impounds the Santa Ynez