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<br />III. HYDROLOGY <br /> <br />Hydrologic information required for the evaluation and design of the Uncompallgre River <br /> <br />Redevelopment Project includes peak discharges by return period for the Uncompahgre, hydrographs <br /> <br />associated with peak discharges on tle Uncompahgre and an annual ftow duration curve. In addition. <br /> <br />hydrologic information for tributaries includes peak discharges and volume associated with peak events. The <br /> <br />tributary information includes both watHr only and bulked values to account for mud and debris fiows. The <br /> <br />tributaries of interest are Skyrocket and Bridalveil Creeks which enter within the project and Cascade and <br /> <br />Portland Creeks. which enter upstrearr of the project. <br /> <br />The drainage areas of the Unc'Jmpahgre and the tributaries are listed below: <br /> <br />Uncompahgre above Portland Creek <br />Uncompahgre above Project <br />Uncompahgre below Project <br />Portland Creek <br />Cascade Creek <br />Skyrocket Creek <br />Bridalveil Creek <br /> <br />70 sq. mi. <br />713 sq. mi. <br />80 sq, mi. <br />28 sq. mi. <br />13 sq. mi. <br />07 sq. mi. <br />0,7 sq. ml. <br /> <br />3.1 Peak Events <br /> <br />Peak discharges associated with both the Uncompallgre and its tributaries are presented in this <br /> <br />section. These values were taken from existing reports. including FEMA (1985), A&S Consultants (1978) and <br /> <br />Simons, Li & Associates (1982). <br /> <br />3.1.1 Uncompahare River <br /> <br />The Uncompahgre River peak e,vents are attributable to snowmelt and occur in May and June. The <br /> <br />peak discharges were developed utilizing Log Pearson Type III method as presented in Water RE,sources <br /> <br />Council Bulletin 17B (WRC. 1981). The peak discharges at the upstream end of the project as idfmtified in <br /> <br />FEMA (1985) are: <br /> <br />3.1 <br />