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<br />Cross sections for Sand Creek, Sand Creek East Fork, Sand Creek <br />Center Tributary, Spring Creek, Ke,ttle Creek, ?ine Creek and its <br />tributaries, Mesa Basin, Douglas CIfeek South, Douglas Creek North, <br />Templeton Gap Floodway, Rockrimmon Basin and Peterson Field Drainage <br />were obtained from aerial topographic maps compiled by Landmark <br />Mapping between 1981 and 1983 (Reference 21). <br /> <br />Cross sections for Cottonwood Creek 'below Woodman Road were obtained <br />from the Landmark Mapping maps (Reference 21). Above Woodman Road, <br />cross sections were obtained from COE topographic maps (Reference <br />22). <br /> <br />Cross sections for Templeton Gap Lower Tributary were obtained from <br />"as constructed" channelization plans from the Colorado State <br />Division of Highways (Reference 23). <br /> <br />Locations of selected cross sections used in the hydraulic analyses <br />are shown on the Flood Profiles (Exhibit 1). For stream segments for <br />which a floodway was computed (Section 4.2), selected cross section <br />locations are also shown on the Flood Insurance Rate Map (Exhibit 2). <br /> <br />Roughness factors (Manning's IIn") for these computations were <br />assigned on the basis of field inspections of flood plain areas. <br />Roughness values used for the stream channels and overbank areas <br />varied from 0.013 to 0.080, which correspond to concrete channels and <br />densely vegetated overbanks, respectively. Photographs also aided in <br />the documentation of channel and overpank roughnes9 coefficients. <br /> <br />Starting water-surface elevations were either based on coincident <br />condition elevations, slope-area method or elevations of an adjacent <br />study. <br /> <br />the hydraulic analyses for this study were based on unobstructed <br />flow. The flood elevations shown on the profiles are thus considered <br />valid only if hydraulic structures remain unobstructed, operate <br />properly, and do not fail. <br /> <br />All elevations are referenced to theiNational Geodetic Vertical Datum <br />of 1929 (NGVD). Elevation refennce marks used in this study are <br />shown on the maps. <br /> <br />. <br /> <br />4.0 FLOOD PLAIN MANAGEMENT APPLICATIONS <br /> <br />The NFIP encourages State and local goverriments to adopt sound flood plain <br />management programs. Therefore, each Flo~d Insurance Study provides 100- <br />year flood elevations and delineations of the 100- and SOO-year flood <br />plain boundaries and lOO-year floodway to iassist communities in developing <br />flood plain management measures. <br /> <br />18 <br />