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<br />000358 <br /> <br />PHASE II UPPER COLORADO RIVER STUDY <br />EXECUTIVE SUMMARY <br /> <br />I. Introduction <br /> <br />The Upper Colorado River Basin Study (UPCO) was initiated in 1998 to identify and <br />investigate water quantity and quality issues in the Study Area consisting of Grand and <br />Summit CountiesI. The primary goal of Phase II ofUPCO was to develop the <br />information and analytical tools necessary to understand existing hydrology and water <br />quality conditions in the study area and how increased water diversions may impact those <br />conditions. This information was meant to support discussions and negotiations between <br />the stakeholders as they seek solutions to current and future water supply, reservoir level, <br />instream flow, and water quality issues. Participants in the study were Grand and <br />Summit Counties, Colorado River Water Conservation District (River District), Middle <br />Park Water Conservancy District (Middle Park), Northwest Colorado Council of <br />Government's Water Quality and Quantity Committee (QQ), Northern Colorado Water <br />Conservancy District (Northern), Denver Water (Denver) and Colorado Springs. <br />The principal components of the Phase II study were: 1) compilation and analysis of <br />water resources and water supply data for Summit and Grand Counties; 2) expansion of <br />Denver's hydrologic and water rights model (platte and Colorado Simulation Model, <br />PACSM) to represent individual West Slope water supply systems; 3) development ofa <br />data management and display tool to support the analysis of impacts associated with <br />existing and future water supply and demand scenarios; and, 4) identification of issues to <br />be addressed in Phase III, the solutions phase, ofthe study. <br /> <br />The study analyzed existing and future conditions based on the 1947-1991 hydrologic <br />record. That is, the model used natural or "undepleted" stream flows for those years and <br />accounted for the operation of water rights and demands to predict quantity and timing of <br />water supplies, the depleted stream flows, and reservoir levels under various assumptions <br />for the demands. The 1947-1991 period includes wet, dry and average years but does not <br />include any years that are comparable to drought conditions as severe as what occurred <br />during 2002 when streamflows in certain areas were the lowest ever recorded. Impacts <br />created by the 2002 drought are discussed in more detail on page viii of this Executive <br />Summary. <br /> <br />The UPCO evaluations indicate a need for additional water supplies in Grand and <br />Summit Counties for existing and future municipal demands as well as instream flows to <br />support the area's recreational uses and maintain low-flow levels used to determine waste <br />load allocations for wastewater treatment plants. The key to developing solutions and <br />addressing impacts is cooperation among the UPCO partners as future water projects are <br />planned. <br /> <br />I Phase I ofUPCO was the development of the Scope ofWorl<: for Phase 11. Phase ill, to be initiated in mid-2003, <br />involves a collaborative effort by the participating parties to seek solutions to the issues identified in the Phase 11 study <br />report. <br /> <br />Hydrosphere Resource Consultants, 1002 Walnut, Suite 200, Boulder, CO 80302 <br /> <br />cg~~t. <18"( <br /> <br />:; -.).. 9 - '2.f:J03 <br />