Draft 2025 Water Shortage Contingency Plan

Results of the DRA indicate that IRWD has sufficient supplies to meet its projected demands, even during multiple dry years ( Table 1-3 ). Supplies are expected to exceed IRWD’s projected water use for all future years evaluated ( Table 1-2 and Table 1-3 ). Recycled water is considered a drought resistant supply. Therefore, Table 1-2 and Table 1-3 show only potable supplies and demands. For additional tables and non-potable results refer to the 2025 UWMP Section 7 and Appendix D. The DRA indicates that even in five years of consecutive drought there is a water supply surplus without the use of WSCP response actions. When Metropolitan WSCP response actions trigger a Level 10 shortage condition (more than 50% reduction in imported supplies), IRWD would only be in a Level 1 shortage condition (less than 10%, see WSCP Section 3.1) due to its diversified portfolio and availability of local supplies For additional details on the Multiple Dry Year Analysis and DRA refer to 2025 UWMP Section 7. Table 1 ‑ 2: Multiple Dry Year Water Reliability Analysis – Potable Water DWR Submittal Table 7-4 Retail: Multiple Dry Years Supply and Use Comparison - Potable 2030 2035 2040 2045

Supply totals

101,863 101,863 101,863 101,863

First year

Use totals

55,772 46,091

56,394 45,469

56,911 44,952

56,999 44,864

Surplus/(shortfall)

Supply totals

101,863 101,863 101,863 101,863

Second year

Use totals

56,330 45,533

56,958 44,905

57,480 44,383

57,569 44,294

Surplus/(shortfall)

Supply totals

101,863 101,863 101,863 101,863

Third year

Use totals

56,893 44,970

57,528 44,335

58,055 43,808

58,144 43,719

Surplus/(shortfall)

Supply totals

101,863 101,863 101,863 101,863

Fourth year

Use totals

56,324 45,539

56,953 44,910

57,474 44,389

57,563 44,300

Surplus/(shortfall)

Supply totals

101,863 101,863 101,863 101,863

Fifth year

Use totals

53,508 48,355

54,105 47,758

54,600 47,263

54,685

Surplus/(shortfall) 47,178 NOTES: [1] Use totals are based on average year values provided by MWDOC with a: 5% increase in Year 1; 1% increase in Year 2 and Year 3; 1% decrease in Year 4; and a 5% decrease in Year 5. Source: IRWD 2025 UWMP, DWR Table 7 – 4

WSCP - 12

IRWD – 2025 Water Shortage Contingency Plan

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