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For Little Dry Creek, Big Dry Creek (downstream of Interstate 25), Hidden Lake, Niver Creek, and Northfield Creek, synthetically developed hydrographs were computed to determine potential flood magnitudes. Rainfall data used in the development of these hydrographs were taken from the Denver Regional Council of Government's Urban Storm Drainage Criteria Manual (USDCM) (Reference 23). Synthetic hydrograph procedures used in the study include the Colorado Urban Hydrograph Procedure (CUHP), outlined in the USDCM and the USACE HEC-l Computer Hydrograph Package (Reference 24). Discharges were also computed on Big Dry Creek, prior to the start of this study, by the Denver area UDFCD (Reference 20). The discharges computed for this stream varied only slightly from those computed in the previous study. Therefore, the original information was used. For the larger drainage basins east of the Denver metropolitan area, discharge versus drainage area relationships were developed. These determinations were based on the standard log-Pearson Type III statistical analysis (Reference 25) of flood discharge records from several streams adjacent to the study area as well as in eastern Colorado. The discharge records for the streams considered covered periods from lO to 74 years. The data used in making these determinations were recorded at 18 gaging stations by the USGS and are published as regional flood data (References 26, 27, and 28). Discharges for the 500-year floods were checked by straight line extrapolation of frequencies that were previously determined using the procedure of the USGS (References 27 and 29) and compared to the USACE Standard Project Flood data when available (References 12, 21, and 30). Tributary M of Niver Creek Peak discharges for the lO- and lOO-year floods for Tributary M of Niver Creek were developed using the CUHP (Reference 31) and USACE HEC-l (Reference 24) computer models. The watershed was subdivided into six subbasins. For each subbasin, peak flow hydrographs were developed using the CUHP model. Parameters for the hydro graph development include rainfall data (Reference 32), soil type, land use, basin area, and basin geometry (References 33, 34, and 35). The outflow hydrographs derived for the subbasins were then used for the HEC-l model, which was channel and storage routing capability using the Modified Puls methods. The result from the HEC-l analysis shows that the upper pond near Elm Circle attenuates the lOO-year peak flow from 226 cfs to 200 cfs. The flows vary from 200 cfs upstream to l,086 cfs at Pecos Street. Grange Hall Creek. South Fork Grange Hall Creek. Grange Hall Creek Tributary. Basin 4100. and Brantner Gulch Synthetically developed hydrographs were computed to determine the lO-, 50-, and lOO-year discharges. Rainfall data used ln the development of these hydrographs were taken from the USDCM 25