Section 7 | Water Supply Reliability and ………… Drought Risk Assessment
Law
10635(a) Every urban water supplier shall include, as part of its urban water management plan, an assessment of the reliability of its water service to its customers during normal, dry and multiple dry water years. This water supply and demand assessment shall compare the total water supply sources available to the water supplier with the total projected water use over the next 20 years, in five-year increments, for a normal water year, a single dry water year, and multiple dry water years. The water service reliability assessment shall be based upon the information compiled pursuant to Section 10631, including available data from state, regional or local agency population projections within the service area of the urban water supplier.
This Section 7 provides IRWD’s assessment of its water supply reliability and its ability to meet the water needs of its customers, under varying water year types and is used to evaluate its risk of shortage under a severe drought. It also includes the Drought Risk Assessment (DRA) that requires a Supplier to examine its water supplies, water uses, and the resulting water supply reliability under an assumed drought period lasting five consecutive dry years. IRWD’s available water supply sources are further described in Section 6 and the District’s customer uses are described in Section 4. As described in Sections 4 and 6, IRWD’s system includes both potable and non-potable supplies and demands. Non-potable supplies are conveyed through an extensive separate non-potable distribution system. Therefore, IRWD included the optional tables in this Section 7 to show the separate analysis for potable and non- potable water supplies and demands.
7.1 Constraints on Water Sources Considerations Law
10631b(1). A detailed discussion of anticipated supply availability under a normal water year, single dry year, and droughts lasting at least five years, as well as more frequent and severe periods of drought, as described in the drought risk assessment. For each source of water supply, consider any information pertinent to the reliability analysis conducted pursuant to Section 10635, including changes in supply due to climate change.
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IRWD – 2025 Urban Water Management Plan
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