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was constructed for the 400-square-mile area above the Golden gage, and a storm water management model (Reference 17) was constructed for the l75-square-mile area between the Golden and Derby gages. The rainfall depths used in the analysis were based on data obtained from the 1973 National Oceanic and Atmospheric Adm1nistration report, Precipitation-Frequency Atlas of the Western United States, Volume Ill, Colorado (Reference 18). The runoff models were calibrated against the discharge records available at the respective stream gages. The 10-, 50-, and 100-year peak discharges for Kenneys Run were calculated using the CUHP (Reference 14). The design rainfall data were supplied by the UDFCD based on values obtained from Precipitation-Frequency Atlas of the Western United States, Volume Ill, Colorado (Reference 18). Peak discharges at selected locations 1n the study reaches were obtained by routing the flood hydrographs for each subbasin computed by the CUHP. The peak discharges for Lena Gulch, upstream of West 6th Avenue, and Jackson Gulch were obtained from a 1975 study done for the UDFCD by Wr1ght-McLaughlin Engineers (Reference 19). In this stu- dy, the GUHP was used to calculate the 10-, 25-, and 100-year dis- charges for present and future development conditions. The design ra1nfall used 1n the study was supplied by the UDFCD, based on information from Precipitation-Frequency Atlas of the Western United States, Volume Ill, Colorado (Reference 18). During this stUdy, the dra1nage area of Lena Gulch was field checked to deter- mine tha t current development condi tions would be properly reflected by the estimated future development conditions reported in the 1975 UDFCD study. The future development conditions for flood discharge values from the 1975 study (Reference 19) were determ1ned to be valid for this Flood Insurance Study. The 50- and 500-year d1scharges were estimated from the frequency curves based on the 10-, 25-, and 100-year discharge values. Peak discharge-dra1nage area relationsh1ps for the flooding sour- ces of Jefferson County, Colorado, are shown in Table 1. 3.2 Hydraulic Analyses Analyses of the hydraulic characteristics of flooding from the Bources studied were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. For the South Platte River, the water-surface of the selected recurrence intervals were U.S. Soil Conservation Service WSP2 (Reference 20). These profiles and elevations historic floods, and the flood stages were then elevations of floods computed using the computer program were compared wi th determined. 11