B.2 Summary of Expected Outcomes for Reduced Reliance on the Delta
IRWD receives supplemental imported water supplies from the regional water wholesaler Metropolitan Water District of Southern California (Metropolitan) through the Municipal Water District of Orange County (MWDOC), a member agency of Metropolitan that serves Orange County. Metropolitan imports water into its region from the Delta and the Colorado River. As the regional wholesaler of imported water, Metropolitan has evaluated the expected outcomes for reduced reliance on the Delta on a region-wide scale that includes its member agencies. This is documented in Appendix 10 of Metropolitan’s 2025 UWMP. Metropolitan’s findings show that its expected outcomes for regional self-reliance under both the near-term (2030) and long-term (2050) are increased over time with measurable reduced reliance on the Delta. This analysis is further described in this report under Section B.4 “Supplies Contributing to Regional Self Reliance”. While IRWD’s supplies and demands factor into the Metropolitan analysis through MWDOC, this document reports IRWD’s own expected outcomes for regional self-reliance and reduced reliance on the Delta. These expected outcomes have been developed using the approach and guidance described in Appendix C of Department of Water Resources’ (DWR) Urban Water Management Plan Guidebook 2025 – Final Draft (Guidebook Appendix C) issued in January 2026. IRWD’s results summarized below show that IRWD individually, is measurably reducing reliance on the Delta and improving regional self-reliance, both in terms of the amount of water used and as a percentage of water used. Summary of Expected Outcomes for IRWD’s Self-Reliance Near-term (2030) – Normal water year regional self-reliance is expected to increase by 163,987 AF from the 2010 baseline; this represents an increase of about 44 percent of 2030 normal water year retail demands (See Table B-2 ). Long-term (2045) – Normal water year regional self-reliance is expected to increase by 164,634 AF from the 2010 baseline, this represents an increase of 43 percent of 2045 normal water year retail demands (See Table B-2 ). The analysis provided in this appendix includes all the elements described in WR P1(c)(1) that need to be included in a water supplier’s UWMP to support a certification of consistency for a future covered action.
Appendix B - 4
IRWD – 2025 Urban Water Management Plan – Reduced Delta Reliance
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