Item 28 - Urban Water Management Plan and Water Shortage Contingency Plan

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Service Area Demands with Water Use Efficiency The service area demands shown in Table C-1 represent the total retail water demands for the City’s service area and may include municipal and industrial demands, agricultural demands, recycled, seawater barrier demands, and storage replenishment demands. These demand types and the modeling methodologies used to calculate them are described in Section 4-3 of the City’s UWMP. Non-Potable Water Demands Any non-potable water demands shown in Table C-1 represent demands for non-potable recycled water, water used for purposes such as surface reservoir storage, and replenishment water for groundwater basin recharge and sweater barrier demands. Additionally, non-potable supplies have a demand hardening effect due to the inability to shift non-potable supplies to meet potable water demands. When water use efficiency or conservation measures are implemented, they fall solely on the potable water users. This is consistent with the approach for water conservation reporting used by the State Water Resources Control Board. Total Service Area Population The City’s total service area population as shown in Table C-1 come from the Center for Demographic Research, with actuals and projections further described in Section 3.4 of the City’s 2020 UWMP. Water Use Efficiency Since Baseline The water use efficiency numbers shown in Table C-1 represent the formulation that City utilized, consistent with Appendix C of the UWMP Guidebook approach. Service area demands, excluding non-potable demands, are divided by the service area population to get per capita water use in the service area in gallons per capita per day (GPCD) for each five-year period. The change in per capita water use from the baseline is the comparative GPCD from that five-year period compared to the 2010 baseline. Changes in per capita water use over time are then applied back to the City’s service area population to calculate the estimated WUE Supply. This estimated WUE Supply is considered an additional supply that may be used to show reduced reliance on Delta water supplies. The demand and water use efficiency data shown in Table C-1 were collected from the following sources: Baseline (2010) values – City’s 2005 UWMP 2015 values – City’s 2010 UWMP 2020 values – City’s 2015 UWMP 2025-2040 values – City’s 2020 UWMP It should be noted that the results of this calculation differ from what the City calculated under section 5.2 pertaining to the Water Conservation Act of 2009 (SB X7-7) due to differing formulas. C.4 Supplies Contributing to Regional Self-Reliance For a covered action to demonstrate consistency with the Delta Plan, WR P1 subsection (c)(1)(C) states that water suppliers must report the expected outcomes for measurable improvement in regional self-reliance. Table C-2 shows expected outcomes for supplies contributing to regional self-reliance both in amount and as a percentage. The numbers shown in Table C-2 represent efforts to improve regional self-reliance for the City’s entire service area and include the total contributions of the City. Supporting narratives and documentation for the all of the data shown in Table C-2 are provided below. The results shown in Table C-2 demonstrate that the City’s service area is measurably improving its regional self- reliance. In the near-term (2025), the expected outcome for normal water year regional self-reliance increases by 25,806 AF from the 2010 baseline; this represents an increase of about 48.4 percent of 2025 normal water year retail demands. In the long-term (2040), normal water year regional self-reliance is expected to increase by more than 28,706 AF from the 2010 baseline; this represents an increase of about 53.1 percent of 2040 normal water year retail demands.