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Section 6 2025 Urban Water Management Plan Water Supply Characterization City of Pleasanton Public Draft | May 2026 6-8 EKI Environment & Water, Inc. The Basin is not adjudicated. In its evaluation of California groundwater basins, DWR determined that the Basin is not in a condition of critical overdraft.11 Rather, the Basin is designated as a medium priority basin under DWR’s 2019 Phase 2 Basin Prioritization,11 which scores basins on eight components and ranks their priority based on the scores. If a basin is assigned more than 14 but less than 21 total points, it is defined as “medium priority.” In the case of the Basin, a total of 16 points were assigned, resulting in a designation as “medium priority.” The main factors driving the Basin’s designation include total population (3 out of 5 possible points), population growth (3 out of 5 possible points), numbers of public supply wells (3 out of 5 possible points), and total numbers of wells (3 out of 5 possible points). The Basin covers an area of approximately 69,600 acres (109 square miles) and is located about 40 miles east of San Francisco and 30 miles southwest of Stockton within a structural trough of the Diablo Range. The Basin extends from the Pleasanton Ridge east to the Altamont Hills (about 14 miles) and from the Livermore Upland north to the Orinda Upland (about 13 miles). Surface drainage features include Arroyo Valle, Arroyo Mocho, and Arroyo las Positas as principal streams, with Alamo Creek, South San Ramon Creek, and Tassajara Creek as minor streams. Elevations within the Basin range from about 600 feet above mean sea level (ft msl) in the east, near the Altamont Hills, to about 280 ft msl in the southwest, where Arroyo de la Laguna flows into the Sunol Basin. DWR's Groundwater Bulletin 118 and key documents described below provide additional details provided related to groundwater management in the Basin : • The updated Livermore Valley Basin Alternative Groundwater Sustainability Plan (“Alternative GSP”), which includes current groundwater conditions, a hydrogeologic conceptual model, a water budget, local sustainable management criteria, and projects and management actions for maintaining sustainability in the Basin, available on the DWR’s SGMA Portal website here: https://sgma.water.ca.gov/portal/alternative/periodiceval/preview/8 • The Annual Report for the Sustainable Groundwater Management Program, 2025 Water Year, Livermore Valley Groundwater Basin, available on the Zone 7 website https://www.zone7waterca.gov/sustainable-groundwater-management-and-sgma • The Bay Area Integrated Regional Water Management Plan (IRWMP), including detailed descriptions of local and regional hydrogeology, groundwater conditions, and groundwater monitoring practices, available on the Bay Area IRWMP website: http://bayareairwmp.org/irwm-plans/ 11 DWR, 2019. Sustainable Groundwater Management Act 2018 Basin Prioritization, State of California, dated January 2019.