Item 21 - Public Hearing - Resolutions Approving the 2025 Urban Water Management Plan and the 2025 Water Shortage Contingency Plan

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2025 URBAN WATER MANAGEMENT PLAN MAY 2026/FINAL DRAFT/CAROLLO BPP Adjustments for Basin Management OCWD has established management guidelines that are used to establish future BPPs, as seen in Table 6.9. Raising or lowering the BPP allows OCWD to manage the amount of pumping from the basin. OCWD has a policy to manage the groundwater basin within a sustainable range to avoid adverse impacts to the basin. OCWD seeks to maintain some available storage space in the basin to maximize surface water recharge when such supplies are available, especially in relatively wet years. By keeping the basin relatively full during wet years, and for as long as possible in years with near-normal recharge, the maximum amount of groundwater could be maintained in storage to support pumping in future drought conditions. During dry hydrologic years, when less water is available for recharge, the BPP could be lowered to maintain groundwater storage levels.A component of OCWD's BPP policy is to manage the groundwater basin so that the BPP will not fluctuate more than 5 percent from year to year. Table 6.9 Management Actions Based on Changes in Groundwater Storage Available Storage Space Basin Management Action to Consider (amount below full basin condition,AF) Less than 100,000 Raise BPP 100,000 to 300,000 Maintain and/or raise BPP towards 85%goal 300,000 to 350,000 Seek additional supplies to refill basin and/or lower the BPP Greater than 350,000 Seek additional supplies to refill basin and lower the BPP The OCWD's GWRS came online in 2008 with a capacity of approximately 70 million gallons per day (mgd) and was expanded to 100 mgd in 2015. In 2023, it was expanded again to a final capacity of 130 mgd.The GWRS provides a resilient local water supply that recharges the Orange County groundwater basin with advanced treated wastewater. The additional yield supported OCWD's move to raise the BPP from the long-standing approximately 77 percent level prior to 2023 to 85 percent beginning in February 2023. Monthly water-resources reports show agencies achieving 86 to 88 percent pumping shares after the final expansion from late 2024 to early 2025, reflecting how GWRS production has enabled higher local reliance over the last decade, along with the relatively low water demands of approximately 400,000 AFY. Modeling and forecasts generate estimates based on historical averages. Consequently, forecasts use average hydrologic conditions,which smooth the dynamic and unpredictable local hydrology.Variations in local hydrology are the most significant impact to supplies of water available to recharge the groundwater basin. The current BPP of 85 percent is based on modeling of average annual rainfall weather patterns and estimated groundwater recharge volumes. If OCWD were to experience a relatively dry period, the BPP could be reduced to maintain water storage levels, by as much as 5 percent. Basin Equity Assessment Exemptions In some cases, OCWD encourages treating and pumping groundwater that does not meet drinking water standards in order to protect water quality. This is achieved by using a financial incentive called the BEA Exemption.A BEA Exemption is used to promote beneficial uses of poor-quality groundwater and reduce or prevent the spread of poor-quality groundwater into non-degraded aquifer zones. OCWD uses a partial or total exemption of the BEA to compensate a qualified participating agency or Producer for the costs of treating poor quality groundwater, which typically include capital, interest and operations and maintenance costs for treatment facilities (City of La Habra et al., 2017). Similarly, for proactive water quality management, OCWD exempts a portion of the BEA for their Coastal Pumping Transfer Program CITY OF SANTA ANA