2025 Urban Water Management Plan

Section 6 2025 Urban Water Management Plan Water Supply Characterization City of Pleasanton Public Draft | May 2026 6-3 EKI Environment & Water, Inc. 6.1.2.1.2 Table A Allocation Each SWC’s individual contract sets a maximum annual SWP supply limit, specified in Article 6(c) and Table A of the contract. This supply limit is commonly referred to as “Table A.” Following the initial agreement in 1961, DWR amended Zone 7’s contract over the years and increased its Table A amount to 46,000 AFY in 1997. Since then, Zone 7’s Table A amount has increased to 80,619 AFY through a series of five permanent transfers from other SWCs, including: • In December 1999, Zone 7 secured Table A SWP allocations from Lost Hills Water District of 15,000 AFY and Berrenda Mesa Water District of 7,000 AFY. • In December 2000, Zone 7 acquired 10,000 AFY of SWP allocation from Belridge Water Storage District. • In October 2003, Zone 7 obtained an additional 2,219 AFY was obtained from Belridge Water Storage District. • Finally, in 2003, Zone 7 acquired 400 AFY from the Tulare Lake Basin Water Storage District. In practice, the SWP water available to Zone 7 under the Table A allocation process (presented as % of the Table A allocation) varies from year to year due to hydrologic conditions, water demands of other SWCs, existing SWP stored water, SWP facility capacity, and environmental/regulatory requirements. The Table A allocation is typically less than 100% of the Table A amount. SWP reliability is defined based on the long- term average Table A allocation. DWR prepares a biennial SWP Delivery Capability Report (DCR) to assist SWCs and local planners in assessing the availability of supplies from the SWP. DWR issued its most recent update, the Draft 2025 DCR, in December 2025. In this update, DWR provided SWP supply estimates for SWCs to use in their planning efforts, including for use in their 2025 UWMPs. The Draft 2025 DCR includes DWR’s estimates of SWP water supply availability under both existing (2025) and future (2043) conditions. DWR’s estimates of SWP deliveries are based on the CalSim 3 computer model that simulates monthly operations of the SWP and Central Valley Project (CVP) systems. Key inputs to the model include the relevant facilities included, hydrologic inflows, regulatory and operational constraints, and contractor demands for both CVP and SWP water. In conducting its model studies, DWR develops assumptions and/or scenarios for these key inputs. In the Draft 2025 DCR, for existing conditions, DWR assumes: existing facilities, hydrologic inflows based on 100 years of historical data (1921 through 2021) adjusted to incorporate recent changes to climate; current regulatory and operational constraints including 2018 Coordinated Operation Agreement (COA) Amendment, 2024 Biological Opinions, and 2024 SWP Incidental Take Permit; and SWC demands at maximum Table A amounts. The long-term average allocation reported in the Draft 2025 DCR for the existing conditions provides an appropriate estimate for current SWP water supply availability. To evaluate SWP supply availability under future conditions, the Draft 2025 DCR includes three scenarios for climate change conditions in 2043 that represent different risk-informed levels of concern surrounding how climate change uncertainty will impact rising temperatures, shifting precipitation patterns, reduced snowpack, sea level rise, and other factors impacting future SWP water availability. The three risk- informed climate scenarios (50%, 75%, and 95% level of concern) are defined based on projected climate- informed system performance levels of April-to-July unimpaired runoff (Eight River Index) in the Delta watershed for 2028-2057. The 50% level of concern represents a middle-of-the-road or central tendency future, while the 75% level of concern scenario represents a worse than average future, and the 95% level of concern represents much worse. A 95% level of concern scenario depicts a future condition with lower SWP reliability than what results from 95% of model-informed climate outcomes.