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

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C.2 Summary of Expected Outcomes for Reduced Reliance on the Delta As stated in WR P1 (c)(1)(C), the policy requires that, commencing in 2015, UWMPs include expected outcomes for measurable reduction in Delta reliance and improved regional self- reliance. WR P1 further states that those outcomes shall be reported in the UWMP as the reduction in the amount of water used, or in the percentage of water used, from the Delta. The expected outcomes for the City of Santa Ana (hereafter referred to as ‘City’) regional self-reliance were developed using the approach and guidance described in Appendix C of DWR’s Urban Water Management Plan Guidebook 2020 – Final Draft (Guidebook Appendix C) issued in March 2021. The data used in this analysis represent the total regional efforts of Metropolitan, the city, and its member agencies and were developed in conjunction with Metropolitan as part of the UWMP coordination process. The following provides a summary of the near-term (2025) and long-term (2045) expected outcomes for the city’s Delta reliance and regional self-reliance. The results show that as a region, the City, Metropolitan, and its member agencies are measurably reducing reliance on the Delta and improving regional self-reliance, both as an amount of water used and as a percentage of water used. Expected Outcomes for Regional Self-Reliance for the City Near-term (2025) – Normal water year regional self-reliance is expected to increase by 25,806 AF from the 2010 baseline; this represents an increase of about 48.4 percent of 2025 normal water year retail demands (Table C-2). Long-term (2040) – Normal water year regional self-reliance is expected to increase by nearly 28,706 AF from the 2010 baseline, this represents an increase of about 53.1 percent of 2045 normal water year retail demands (Table C-2). C.3 Demonstration of Reduced Reliance on the Delta The methodology used to determine the City’s reduced Delta reliance and improved regional self-reliance is consistent with the approach detailed in DWR’s UWMP Guidebook Appendix C, including the use of narrative justifications for the accounting of supplies and the documentation of specific data sources. Some of the key assumptions underlying the City’s demonstration of reduced reliance include: All data were obtained from the current 2020 UWMP or previously adopted UWMPs and represent average or normal water year conditions. All analyses were conducted at the service area level, and all data reflect the total contributions of the City and MWDOC, in conjunction with information provided by Metropolitan. No projects or programs that are described in the UWMPs as “Projects Under Development” were included in the accounting of supplies. Baseline and Expected Outcomes In order to calculate the expected outcomes for measurable reduction in Delta reliance and improved regional self-reliance, a baseline is needed to compare against. This analysis uses a normal water year representation of 2010 as the baseline, which is consistent with the approach described in the Guidebook Appendix C. Data for the 2010 baseline were taken from the city’s 2005 UWMP as the UWMPs generally do not provide normal water year data for the year that they are adopted (i.e., 2005 UWMP forecasts begin in 2010, 2010 UWMP forecasts begin in 2015, and so on). Consistent with the 2010 baseline data approach, the expected outcomes for reduced Delta reliance and improved regional self-reliance for 2015 and 2020 were taken from the City’s 2010 and 2015 UWMPs respectively. Expected outcomes for 2025-2040 are from the current 2020 UWMP. Documentation of the specific data sources and assumptions are included in the discussions below. Service Area Demands without Water Use Efficiency In alignment with the Guidebook Appendix C, this analysis uses normal water year demands, rather than normal