Agenda - 03-02-2006-7b - Laserfiche WebLink

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Mow Does OWASA Estimate Future Demands for Water and Wastewater Service? Future demand projections axe generated from currently available information about plans for major new development activities (such as UNC's main campus and Carolina North), changes in local building trends, recent water consumption data and trends, reuse projections from the University, and assumptions about future water conservation anxong all customer classes. A list of key assumptions and information sources on which OWASA's most current projections axe based is presented in Attachment C. Wastewater demand projections are generated by applying an empirically derived factor of 0.92.3 to corresponding drirllcing water demand projections, reflecting the fact that only a portion of the drinking water used in the community is returned as wastewater, A spreadsheet with detailed calculations and results is available on request.. Long-term demand forecasts extend through 2050, when we assume that build-out will have occurred; i.e., forecasts for 2050 represent OWASA's best guess at "ultimate" capacity needs. We recognize that Carrboro's and Chapel Hill's projections of future population and emplo}anent, as reflected in Transportation Analysis Zone (TAZ) data, do not extend beyond 2030 or 20.35, and that both towns expect to be substantially built out by then. OWASA's pr~ojectioras of future water mrd wastewater treatment demands therefore con°espwtd to housing and employment levels that exceed Cm°rboro's ar:d Clsapel Hill's buildout projections by more than 20 percent. We believe that tlris provides a conservative margin of safety for meeting the capacity needs of future development. We also recognize that the actual pace and timing of growth in the community and the University may result in short-terns departures from our projected demand trends, but such departures are not expected to affect long-terns estimates of water and sewer system capacity needs. As more detailed o owth plans are developed by Carrboro, Chapel Hill, and UNC, OWASA will continue to revise and refine our pxo,jected demands accordingly.. We expect, for example, that the more or less linear pattern assumed for future b owth (as depicted in Figure 1), will likely bend upward in the middle years before leveling off at or below projected buildout levels, Are There Any Options for Additional Water Supply Sources That Could Reduce Our Vulnerability to Severe Droughts Before the Expanded Stone Quarry Is Available in the 2030s? OWASA's 5 percent allocation of the Jordan Lake water supply storage capacity will yield an average of about 5 mgd. If used by our community, this could substantially reduce our vulnerability to severe droughts until the expanded Quarry Reservoir is available in the 20.30s. However, constructing facilities to obtain and transport water from Jordan Lake to OWASA's water treatment plant in Canboro would cost approximately $45 million in today's (2006) dollars - an expensive investment for a OWASA -Water and Sewer Capacity /mplicatiars of tncrensed Derelopnrent De»sity Page 9 0~ ZI