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<br />I. <br />I <br /> <br />f. Detailed briefa of the public hearings and meetings are <br />presented in appendix XII. <br /> <br />14. PROBLEM AllALYSIS <br /> <br />Because of the hydrologic inter-relationships between the <br />Cherry Creek and Sand Creek basins, caused by the existence of <br />the Cherry Creek emergency spillway, problem analysis _s <br />initially focused on Cherry Creek Reservoir and the Cherry Creek <br />basin. Section II of this report presents the problems and <br />solutions associated with the Cherry Creek basin. Sand and <br />Toll Gate Creeks are discussed in Section III. Problems and <br />potential solutions associated with Westerly Creek, a left-bank <br />tributary of Sand Creek, are essentially limited to the Westerly <br />Creek drainage area and are the subject of a separate report. <br /> <br />II. CHERRY CREEK BASIN <br /> <br />15. PROBLEMS CONSIDERED <br /> <br />a. Flood prOblem. <br /> <br />(1 ) Cherry Creek D8lll and Reservoir. A remote but <br />potentially severe flood threat exists along Toll Gate and Sand <br />Creeks from discharges through the Cherry Creek Reservoir <br />emergency spillway. If a spillway design flood were to occur <br />with the flood control pool in the Cherry Creek Reservoir at <br />its maximum level, a peak discharge of 45,000 cubic feet per <br />second would be diverted into the Sand Creek basin. Damages <br />of at least $7.8 million and $83.4 million under existing and <br />future conditions of development, respectively, would occur <br />alollg Toll Gate and Sand Creeks. Wind-wave action, which could <br />be reasonably expected to occur, would cause overtopping of the <br />Cherry Creek Dam causing additional damages along Cherry Creek. <br /> <br />(2) If the flood control pool were half-full when a <br />spillway design flood occurred, a maximum peak discharge of <br />30,000 cubic feet per secolld would be diverted into the Sand <br />Creek basin. Damages of at least $5.5 million and $58.8 million <br />under existing and future conditions of development, respectively, <br />would occur along Toll Gate and Sand Creeks. <br /> <br />(3) Diversion of Cherry Creek vater into the Sand Creek <br />basin is possible with various combinatiolls of antecedent pool <br />levels and flood inflows. For example, any cOlllbination of <br />successive floods having a total volume in excess of 107 percent <br /> <br />"R" Jan 72 <br /> <br />.' ~. <br /> <br />20 <br /> <br />30S9 <br />