2025 Urban Water Management Plan

Section 6 2025 Urban Water Management Plan Water Supply Characterization City of Pleasanton Public Draft | May 2026 6-10 EKI Environment & Water, Inc. management actions. The update included revised minimum thresholds and measurable objectives where appropriate, updated water budget analyses, enhanced evaluation of interconnected surface water conditions, and documentation of ongoing management measures such as the GPQ, artificial recharge operations, and monitoring programs. DWR approved the first Periodic Evaluation of the Alternative GSP in June 2024, confirming that Zone 7 continues to meet SGMA requirements and is managing the Basin sustainably. Under SGMA, Zone 7 is also responsible for annual reporting and Five-Year Periodic Evaluations to demonstrate continued progress toward sustainability. Zone 7’s latest Annual Report was developed for Water Year 2025. The second Five-Year Periodic Evaluation of the Alternative GSP is being prepared and is due to DWR by December 21, 2026. 6.2.3.1 Sustainable Yield and Allocation across Main Basin Groundwater Users Zone 7 continues to operate the Basin within its Sustainable Yield over a long-term period (10 years) and manage groundwater resources to prevent significant chronic lowering of groundwater levels and reduction of groundwater storage. Zone 7 determined historic lows by measuring groundwater elevations in multiple Main Basin wells and identifying the minimum observed level. Zone 7 also defines operational storage as the difference in surface water elevation between a full Main Basin and its historic low. The total storage capacity of the Basin is about 254,000 AF, of which about 126,000 AF is managed as operational storage (Zone 7, 2026). Moreover, pumping is managed to keep groundwater within the operational storage band and above emergency reserved levels. Using over a century of hydrologic records and projected future recharge conditions, the long-term natural sustainable yield of the Main Basin was determined to be 13,400 AFY, which is about 11% of the operational storage. Table 6-1 summarizes how this sustainable yield is allocated among non-Zone 7 groundwater users. Table 6-1 Natural Sustainable Yield Demand Components Demand Component of the Sustainable Yield Sustainable Average (AFY) Pleasanton 3,500 Cal Water 3,069 DSRSD 645 Other Groundwater Pumping 1,186 Agricultural Pumping 400 Mining Area Losses 4,600 Total 13,400