(ii) Current year available supply, considering hydrological and regulatory conditions in the current year and one dry year. The annual supply and demand assessment may consider more than one dry year solely at the discretion of the urban water supplier. (iii) Existing infrastructure capabilities and plausible constraints. (iv) A defined set of locally applicable evaluation criteria that are consistently relied upon for each annual water supply and demand assessment. (v) A description and quantification of each source of water supply. 2.2 Annual Water Supply and Demand Assessment Procedures CWC Section 10632(a)(2) requires that urban water suppliers prepare and submit an Annual Water Supply and Demand Assessment (AWSDA). IRWD’s AWSDA is a determination of the near-term outlook for supplies and demands and identification of any expected shortage that may prompt response actions in the current year. IRWD’s AWSDA supply and demand estimates may differ from IRWD’s projections used for long term planning and are not intended for that purpose. Available supplies are assessed through ongoing coordination with wholesalers, groundwater managers, and IRWD facility operators and staff. Due to the nature of IRWD’s water supply system, many supplies are tracked and managed directly by IRWD on an operational basis. IRWD’s diversified water portfolio allows for multiple sources to be available to meet projected customer demands in varying circumstances. To project water demands for the AWSDA reliability analysis, IRWD uses historical customer water usage data. This data is evaluated in conjunction with local weather conditions, estimated water use requirements, and is adjusted to account for population growth. IRWD has implemented successful water use efficiency and outreach programs since the early 1990’s. These efforts, combined with the long-term use of budget-based rates, have resulted in IRWD having relatively consistent levels of customer water use demands, and less discretionary water use over time. The AWSDA considers this customer use trend in the overall analysis. The following AWSDA methodology includes a written decision-making process to determine water supply reliability. Once completed, the AWSDA is reviewed by IRWD’s senior management. A. Key Data Inputs The following data components are important inputs to the preparation of IRWD’s AWSDA. 1) The first component of the AWSDA, is the estimated acre-feet (AF) of water sales derived from customer usage data. This is based on actual water sales from previous fiscal years (FY). The customer usage data is categorized by water type (treated, untreated, recycled) as well as customer type. Actual water sales are tracked and finalized at the end of each FY in a database managed by the IRWD Finance Department.
2) The second component of the AWSDA is the availability of water supplies by water type (treated, untreated, recycled) in AF. IRWD’s Operations Department provides estimates
WSCP - 15
IRWD – 2025 Water Shortage Contingency Plan
Powered by FlippingBook