CAWELO GROUNDWATER SUSTAINABILITY AGENCY Cawelo GSA Groundwater Sustainability Plan REVIEW DRAFT August 29, 2019 2490 Mariner Square Loop, Suite 215 Alameda, CA 94501 510.747.6920 www.toddgroundwater.com PROFESSIONAL CERTIFICATION Table of Contents Executive Summary ..........................................................................................................1 1. Introduction ...........................................................................................................1 1.1. Purpose of the Groundwater Sustainability Plan ...................................................................... 1 1.2. Agency Information (REG. § 354.6) ........................................................................................... 1 1.3. GSP Organization ....................................................................................................................... 4 2. Cawelo GSA Plan Area .............................................................................................5 2.1. Description of the Plan Area ..................................................................................................... 5 2.2. Water Resources Management ............................................................................................... 10 2.3. Water Resources Monitoring .................................................................................................. 13 2.4. Land Use .................................................................................................................................. 21 2.5. General Plans ........................................................................................................................... 22 2.6. Well Permitting........................................................................................................................ 24 2.7. Regulatory Framework of Oil Field Operations ....................................................................... 25 2.8. Notice and Communication ..................................................................................................... 28 3 Basin Setting ......................................................................................................... 29 3.1 Hydrogeologic Conceptual Model (Reg. § 354.14) .................................................................. 29 3.2 Current and Historical Groundwater Conditions (Reg. § 354.16) ........................................... 49 3.3 Management Areas ................................................................................................................. 66 3.4 Data and Knowledge Gaps ...................................................................................................... 66 4 Water Budget ....................................................................................................... 68 4.1 Water Budget Approach .......................................................................................................... 68 4.2 Study Period ............................................................................................................................ 69 4.3 Historical and Current Water Budget ...................................................................................... 70 4.4 C2VSimFG-Kern Model Water Budget Analysis....................................................................... 82 4.5 Change in Groundwater Storage ............................................................................................. 85 4.6 Projected Water Budgets ........................................................................................................ 88 4.7 Projected Water Budget Results using C2VSimFG-Kern ......................................................... 95 4.8 Data and Knowledge Gaps for the Water Budget Analysis ..................................................... 95 5 Sustainability Goal and Undesireable Results ......................................................... 97 5.1 Sustainability Goal ................................................................................................................... 97 5.2 Approach to Undesirable Results ............................................................................................ 98 5.3 Chronic Lowering of Groundwater Levels ............................................................................... 98 5.4 Reduction of Groundwater Storage ...................................................................................... 101 5.5 Seawater Intrusion ................................................................................................................ 102 5.6 Land Subsidence .................................................................................................................... 103 5.7 Degraded Water Quality ....................................................................................................... 105 5.8 Depletions of Interconnected Surface Water ....................................................................... 106 Groundwater Sustainability Plan REVIEW DRAFT Cawelo GSA i TODD GROUNDWATER 6 Monitoring Network ........................................................................................... 107 6.1 Monitoring Network Objectives ............................................................................................ 107 6.2 Existing Monitoring Programs ............................................................................................... 110 6.3 Groundwater Level Monitoring Networks ............................................................................ 122 6.4 Groundwater Storage Monitoring Networks ........................................................................ 123 6.5 Groundwater Quality Monitoring Networks ......................................................................... 124 6.6 Land subsidence Monitoring Networks ................................................................................ 126 6.7 Surface Water Monitoring Networks .................................................................................... 127 6.8 Representative Regional Monitoring (Reg. § 354.36) ........................................................... 129 6.9 Assessment and Improvement of Monitoring Network (Reg. § 354.38) .............................. 132 6.10 Reporting Monitoring Data to the Department (Reg. § 354.40) ........................................... 134 7 Minimum Thresholds, Measurable Objectives and Interim Milestones ................. 135 7.1 Sustainable Management Criteria ......................................................................................... 135 7.2 Chronic Lowering of Groundwater Levels ............................................................................. 136 7.3 Reduction of Groundwater Storage ...................................................................................... 139 7.4 Land Subsidence .................................................................................................................... 141 7.5 Seawater Intrusion ................................................................................................................ 144 7.6 Degraded Water Quality ....................................................................................................... 144 7.7 Depletions of Interconnected Surface Water ....................................................................... 147 7.8 Coordination with Kern County Subbasin GSAs .................................................................... 147 8 Projects, Management Actions and Adaptive Management ................................. 149 8.1 Overview of Projects and Management Actions ................................................................... 149 8.2 Projects .................................................................................................................................. 149 8.3 Management Actions ............................................................................................................ 159 8.4 Sustainability Assessment ..................................................................................................... 162 8.5 Projected Water Budget Results using C2VSimFG-Kern ....................................................... 164 9 Plan Implementation .......................................................................................... 166 9.1 Schedule for Implementation................................................................................................ 166 9.2 Annual Reporting ................................................................................................................... 166 9.3 Periodic Evaluations .............................................................................................................. 166 10 References and Technical Studies ........................................................................ 167 Groundwater Sustainability Plan REVIEW DRAFT Cawelo GSA ii TODD GROUNDWATER List of Tables Table 3-1 Summary of Wells on Cross Sections Table 3-2 Oilfields and Adjustments to Subbasin Bottom in the Cawelo GSA Area Table 3-3 Well Completion Analysis using Available Data for the Cawelo GSA Table 3-4 Summary Statistics of Select Groundwater Quality Constituents Table 3-5 NCCAG-Mapped Natural Communities Polygons and Acres in the Cawelo GSA Table 4-1 Summary of Imported/Exported Water Deliveries (Acre-Feet per Water Year) Table 4-2 Summary of Groundwater Pumping (Acre-Feet per Water Year)