Laserfiche WebLink
Santa Ana 2020 Urban Water Management Plan <br />arcadis.com <br />4-5 <br />For most retail agencies, the Mid Scenario of CII account growth was used, but for those retail agencies <br />that have had faster historical growth the High Scenario was used. For those retail agencies that have <br />had relatively stable CII water demand, the Low Scenario was used. For Santa Ana, the mid-scenario <br />was used. <br />For those agencies that supply recycled water for non-potable demands, MWDOC used agency-specified <br />growth assumptions. Most agencies have already maximized their recycled water and thus are not <br />expecting for this category of demand to grow. However, a few agencies in South Orange County do <br />expect moderate growth in recycled water customers. <br />For large landscape customers served currently by potable water use, MWDOC assumed these demands <br />to be constant through 2050, except for agencies that have growing recycled water demands. For the <br />agencies that have growing recycled water demands, large landscape demands served by potable water <br />reduced accordingly. For non-revenue water, which represents the difference in total water production <br />less all water billed to customers, this percentage was held constant through 2050. Note that 2050 data <br />was not presented in the UWMP. <br />An agency’s water use demand projection is the summation of their residential water demand, CII <br />demands, large landscape and recycled water demands, and water losses all projected over the 25-year <br />time horizon. These demands were provided to each of the Orange County water agencies for their <br />review, feedback, and revision before being finalized. <br />4.3.1.1 Weather Variability and Long-Term Climate Change Impacts <br />In any given year water demands can vary substantially due to weather. In addition, long-term climate <br />change can have an impact on water demands into the future. For the 2014 OC Water Reliability Study, <br />CDM Smith developed a statistical model of total water monthly production from 1990 to 2014 from a <br />sample of retail water agencies. This model removed impacts from population growth, the economy and <br />drought restrictions in order to estimate the impact on water use from temperature and precipitation. <br />The results of this statistical analysis are: <br /> Hot/dry weather demands will be 5.5% greater than current average weather demands <br /> Cooler/wet weather demands will be 6% lower than current average weather demands <br /> Climate change impacts will increase current average weather demands by: <br />o 2% in 2030 <br />o 4% in 2040 <br />o 6% in 2050 <br />4.3.2 25-Year Water Use Projection <br />The projected demand values were provided by MWDOC and reviewed by the City as part of the UWMP <br />effort. As the regional wholesale supplier for much of Orange County, MWDOC works in collaboration <br />with each of its retail agencies as well as MET (its wholesaler), and the City (who is a direct Member <br />Agency of MET) to develop demand projections for imported water. The City has been proactively <br />decreasing its reliance on imported water by pursuing a variety of water conservation strategies within the <br />service area. Future water savings and low-income water use are included in these projected values.