2025 Urban Water Management Plan

Section 3 2025 Urban Water Management Plan Service Area Description City of Pleasanton Public Draft | May 2026 3-4 EKI Environment & Water, Inc. Figure 3-2 Average Monthly Climatic Conditions Climate change is expected to impact both water availability (supplies) and water demand patterns across California. For example: • Higher temperatures can lead to increases in water use, particularly for irrigation. • Declining snowpack and earlier runoff patterns could result in changes in stream flows and reservoir operations. • Frequent, severe, and prolonged droughts could lead not only to less available surface water, but could also exacerbate ongoing stressors in groundwater basins. Some of these pressures are already apparent in California. According to the Cal-Adapt tool, Pleasanton’s service area experienced a 30-year average temperature of 72.5°F between 1961 and 1990.3 Future projections using Localized Constructed Analogs (LOCA) downscaled Coupled Model Intercomparison Project (CMIP5) model indicate an average increase in temperature of 3.5°F for medium emissions (Representative Concentration Pathway [RCP] 4.5) models and 4.4°F for high emissions (RCP 8.5) models by 2064 (Figure 3-3). Climate projections for precipitation for the area show greater uncertainty compared to temperature projections, exhibiting a wider range of possible outcomes. Cal-Adapt projections using LOCA downscaled CMIP5 models suggest that the maximum 1-day precipitation may increase slightly by 0.08 and 0.09 inches under medium emissions (RCP 4.5) and high emissions (RCP 8.5) scenarios, respectively, relative to historical conditions (Figure 3-4). 3 The Cal-Adapt tool is available at: https://cal-adapt.org/tools/local-climate-change-snapshot