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<br />Peak discharges for Monument Creek from its confluence with Fountain <br />Creek to the northern Colorado Springs study limit were obtained from <br />a COE Flood Plain Information report (Reference 8). A regional gage <br />station analysis was utilized to develop the selected recurrence <br />interval peak flow rates. The hydrologic results contained in this <br />report correlated well with Reference 6 and the Fountain Creek study <br />discussed above (Reference 7). <br /> <br />. <br /> <br />The hydrologic analysis adopted for use in this study for Sand Creek <br />were obtained from a U.S. Soil Conservation Service (SCS) Flood <br />Hazard Analysis report (Reference 9). The SCS report used SCS <br />hydrologic methods to develop peak discharges for the 10-, 50-, and <br />100-year recurrence intervals. Field reconnaissance and the analysis <br />of current land use maps of Colorado Springs were reviewed by the <br />study contractor to ensure that the SCS curve numbers (CN values) <br />were applicable to development in the city. These checks showed no <br />significant changes in land use compared to those used in the SCS <br />report. The SOD-year peak discharge was obtained by extrapolating <br />the 10-, 50-, and 100-year peak discharges on log-probability paper. <br /> <br />Peak discharges for Bear, Camp, Cheyenne, and Cottonwood Creeks, and <br />South Shooks Run were obtained from hydrologic information compiled <br />in a COE report cited earlier (Reference 6). The hydrologic analyses <br />contained therein utilized a synthetic unit hydrograph method to <br />obtain flow rates for the 10-, 50-, and 100-year floodflow rates. <br />Basin data (such as slope, area, soils, channel lengths, and land <br />uses) . were reviewed and found to be accurately estimated for each <br />basin associated with the above streams. The SOD-year peak discharge <br />was obtained through extrapolation of the 10-, 50- and 100-year flood <br />results on log-probability paper. Rainfall patterns and amounts were <br />obtained for each of the above basins using the National Oceanic and <br />Atmospheric Administration (NOAA) data (Reference 10). Flows <br />resulting from this analysis were also checked with those obtained <br />using hydrologic methods outlined in Manual for Estimating Flood <br />Characteristics of Natural Flow Streams (Reference 11) and showed <br />good correlation. <br /> <br />For Kettle and Pine Creeks, and tributaries of Pine Creek, peak flow <br />rates were obtained using the same document (Reference 11). <br /> <br />. <br /> <br />The hydrologic results for Douglas Creek (North and South), Mesa <br />Basin and Rockrimmon Basin drainages, Spring Creek, and for Templeton <br />Gap Floodway and its tributaries were developed using an SCS report <br />entitled Procedures for Determining Peak Floods in Colorado <br />(Reference 12). This methodology is consistent with those outlined <br />in the City of Colorado Springs storm runoff criteria manual <br />(Reference 13), and has been used widely to determine design <br />capacities for flood-control projects throughout the city. Drainage <br />basin studies for all basins except Spring Creek were reviewed to <br />check their adequacy for use in this study. In all the studies <br />reviewed, future development conditions were assumed to obtain the <br />100-year frequency flow rate. Field checks were carried out to check <br />changes in land use since completion of each drainage study, channel <br />alignments and major hydraulic structures which could affect each <br /> <br />13 <br /> <br />J <br />