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5356 ) drinking water standards if the State declares that the alluvial groundwaters are under the innuence of surfacc waters. A combined treatment capacity of3 to 4 million gallons per day would be required to meet the needs of ACWW A and the Cottonwood Water and Sanitation District for diversions from Cherry Creek. Current Water Rights and Water Sources ACWW A maintains a portfolio of water rights to meet its water supply obligations. These water rights include non-tributary wells and alluvial wells throughout the District, along Cherry Creek. ACWW A also operates an augmentation plan that provides for use of the tributar). and non- tributary wells and allows recapture of reusable return nows by pumping the alluvial wells. Preference is given to the use of the tributary groundwater rights to minimize the long-tenn impacts of pumping the nonrenewable deep aquifers. Because of the highly variable nature of Cherry Creek nows from year to year, the yield of the tributary wells is important in establishing the overall water supply availability for ACWW A. These water sources will also be impacted by future development in the Cherry Creek basin as water quality is affected by point and non-point pollution sources. It is possible that treatment of water produced by tributary wells will be required for both potable and non-potable uses if the State considers the alluvial groundwater to be under the innuence of surface waters. \ ) Tributary wells in the Cherry Creek alluvium can pump both in-priority surface water rights on Cherry Creek and reusable return flows from treated emuent discharges and percolated lawn return flows as provided for by the District's augmentation plan. It is assumed that ACWWA can recapture return flows on an annual basis at a rate equivalent to 24% ofwatcr used for outdoor purposes and 8\% of water used for indoor purposes. Dry year yields for tributary wells drawing from the Cherry Creek alluvium are based on creek flows being able to meet water rights senior to an \880 priority date and the rate of recovery of return flows to which Cottonwood is entitled. Table A-4 describes the current allocation of water rights available to ACWW A. Table A-4 - ACWW A Water Rights Classification Aquifer Source Annual Appropriation (ac-ftIyr) Tributary Cherry Creek Alluvium 372" Nontributary Dawson 6\ Denver 274 Arapahoe \,1\2.7 Laramie-Fox Hills 747 Total 2,195 . - Estimated dry year yield for tributary water rights = 372 acre-feet per year )