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<br /> <br />agriculture, and recreation and fishery habitat 'protection and enhancement. <br />Appropriate non-federal interests shall agree to repay the cost allocated to such <br />storage in accordance with the provisions of the Water Supply Act of 1958, the <br />Federal Water Project Recreation Act, and such other Federal laws as the <br />Secretary determines appropriate (33 United Stcltes Code [USC) S 2201 et seq.; <br />Public Law 99-662; 100 Statute 4082). <br /> <br />1.5. SERVICES TO BE PROVIDED. <br />The study is examining the potential for reallocation of storage from flood control to water <br />supply. The study will assure that all impacts are identified and quantified in order to <br />develop the water storage contract costs if it is determined that reallocation is in the best <br />interest of all parties. The study is being completed using both in-house and contract <br />servIces. <br /> <br />1.6. KEY PRODUCTS. <br />The product of the feasibility study, a feasibility report, will be used by the non-Federal <br />Sponsor, other local agencies, and the Corps to provide a complete presentation of the <br />study and results, display the recommended plan, and document compliance with all <br />applicable Federal, State and local statutes, executive orders and policies. The necessary <br />environmental analysis, as applicable to any recommendations or plans, will also be <br />included. Further, it will provide a sound basis for decision makers to judge the <br />recommended plan. <br /> <br />1.7. NEW TASKS. <br />Since the initial PSP several new tasks were identified to be included in the study. The <br />following is a brief description of the tasks. <br /> <br />1.7.1. ANTECEDENT FLOOD STUDY. <br />The purpose of this study was to develop criteria for the antecedent flood to be used in the <br />Inflow Design Flood (IDF) routing for Chatfield Reservoir near Denver, Colorado. As <br />documented in ERll 10-8-2 (FR), Corps of Engineers regulations for routing the Inflow <br />Design Flood require consideration of an antecedent flood of 50 percent of the Probable <br />Maximum Precipitation (PMP) be assumed to occur 5 days prior to the occurrence of the <br />IDE This analysis evaluated the antecedent flood using statistical analysis of historical <br />streamflow and meteorological data. The study found that the antecedent flood criteria of <br />50 percent of the PMP could be reduced to 40 percent. Based on this, Chatfield will meet <br />dam safety requirements to safely pass the IDF/PMF with 20,600 acre-feet of flood <br />storage reallocated to water supply. An independent technical review (ITR) ofthis study <br />was performed by the Bureau of Reclamation and is attached to the report. The report <br />documenting the methodologies and assumptions used will be provided in the Feasibility <br />Report, along with letters of approval from NWD and HQ for a waiver of antecedent <br />flood criteria in ERlllO~8-2(FR). Detailed description of task and the cost estimate <br />provided for this work is available at Appendix C.. <br /> <br />3 <br /> <br />