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The Colorado Urban Hydrograph Procedure hydrologic computer program, designed for hydrologic analyses in the Denver area after major flooding in 1965, was used in the Urban Drainage and Flood Control District report to develop the 10-, 2S-, and 100-year flood dis- charges for these streams. The SO- and SOO-year discharges were extrapolated using the 10-, 2S-, and 100-year discharge information. The 10- and 100-year flood discharges on Goldsmith Gulch and West Tributary to Goldsmith Gulch were taken from a report prepared for the Urban Drainage and Flood Control District (Reference 2). The Urban Drainage and Flood Control District report used the HEC-l computer model to determine the 2-, 10-, and 100-year flood dis- charges, The SO- and SOO-year flood discharges were determined by straight-line extrapolation from this information. A summary of the Frequency Discharge-Drainage Area data is presented on Table 1. 3.2 Hydraulic Analyses Analyses of the hydraulic characteristics of streams in the commu- nity were carried out to provide estimates of the elevations of floods of the selected recurrence intervals along each stream studied in detail in the community. Water-surface elevations of floods of the selected recurrence inter- vals were computed using the U,S, Army Corps of Engineers HEC-2 step-backwater computer program (Reference 7). Cross section data for streams in the area were obtained from 2-foot contour maps (References 1, 2, 3, and 4). Bridge and culvert infor- mation was taken from data used in previous Flood Insurance Studies (References 5, 6, and 8) or in the Urban Drainage and Flood Control District reports (References 1, 2, 3, and 4), Where these data were lacking, field measurements were taken. Locations of selected cross sections used in the hydraulic analyses are shown on the Flood Profiles (Exhibit 1), For stream segments for which a floodway is computed (Section 4.2), selected cross section locations are also shown on the Floodway Map (Exhibit 2). Channel roughness coefficients (Manning's "nil) for these computa- tions were taken from the existing reports except in reaches where field observations indicated unreasonable values. The range of the Manning's "nil factors used in this study were from 0.030 to 0.050 for the channels and from 0.03S to 0.070 for the overbank areas. Flood profiles were drawn showing computed water-surface elevations to an accuracy of 0.5 foot for floods of the selected recurrence intervals. Starting elevations for Big Dry Creek and Little Dry Creek were taken from the Flood Insurance Studies for the Cities of Littleton and Cherry Hills Village, respectively. Weir calculations across S