for treated and untreated water supplies. IRWD Recycled Water Operations provides estimates for production of recycled water-based supplies. Certain supply sources may be limited by existing contractual agreements or wholesaler capacities. Any limitations in supply availability are incorporated into the annual supply assessment. 3) The third component of the AWSDA are adjustments for weather variability (based on dry year and wet year conditions), growth (based on population data from the Center for Demographic Research (CDR), as well as any changes to existing infrastructure capacities or plausible constraints. B. Assessment Methodology and Procedures The preparation of IRWD’s AWSDA uses the following methodology and procedures, which may be expanded and amended in the future. Any such changes will accomplish the same goal of assessing the IRWD’s water supply reliability and potential shortages. Should the assessment indicate a potential shortage, the triggered shortage response actions, compliance and enforcement actions, and communication actions will be consistent with the WSCP as required in CWC Sections 10632 and 10632.1. Step 1: Access Historic Customer Use Data The basis of the IRWD AWSDA is historic customer water use data, compiled in a local database and maintained by the IRWD Finance Department. At the end of each fiscal year, actual water uses, and sales are verified for accuracy. Customer demand projections for the purpose of the AWSDA are based on actual water deliveries tracked by the Finance Department. Customer usage is sorted by supply type and calculated for each FY (July - June) in AF. Units of AF are used throughout the entire AWSDA. In accordance with CWC 10632(a)(2)(B), IRWD considers the projected current year available supply and demand as Year 1 and one dry year as Year 2. Step 2: Determine Available Supplies Estimating available supplies is accomplished by determining the volume of each supply source reasonably anticipated to be available that year and the estimated percentage loss during treatment or delivery based on past operations data. These values are estimated by IRWD facility operators monitoring available supplies (Baker Water Treatment Plant, Irvine Desalter Project, Dyer Road Well Field, Deep Aquifer Treatment System, Wells 21 and 22, Howiler Treatment Plant, Michelson Water Recycling Plant, Los Alisos Water Recycling Plant, recycled water storage reservoirs), and through coordination with water supply partners including but not limited to groundwater managers (Orange County Water District (OCWD)), and wholesalers (Metropolitan and MWDOC) to confirm expected availability of supplies for each year. In addition to estimating available supplies to meet annual customer demands, estimates are also calculated for supplies held in emergency storage in IRWD’s Water Banking Program that can be made available. Through IRWD’s water banking operations in Kern County, IRWD maintains supplies in emergency storage that can be recovered and delivered into IRWD’s service area through a Coordinated Operating, Water Storage, Exchange and Delivery
WSCP - 16
IRWD – 2025 Water Shortage Contingency Plan
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