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<br />Reach 2, were obtained from topographic maps with a contour interval <br />of two feet. (References 25 and 26). In undeveloped areas, field <br />surveys were supplemented using aerial photographs (Reference 14). <br />All bridges and culverts were field checked to obtain elevation <br />data and structural geometry. <br /> <br />Locations of selected cross sections used in the hydraulic analyses <br />are shown on the Flood Profiles. For stream segments for which a <br />floodway is computed (Section 4.2), selected cross section locations <br />are also shown on the Flood Boundary and Floodway Map. <br /> <br />, <br /> <br />Roughness factors (Manning's "n") used in the hydraulic computations <br />were chosen by engineering judgment and based on field observations <br />of the streams and flood plain areas. Channel roughness values used <br />in this study ranged from 0.03 to 0.05. Overbank values ranged from <br />0.05 to 0.14. <br /> <br />Starting water-surface elevations for Eagle River (at Minturn) were <br />obtained using the slope-area method at a starting cross section 800 <br />feet downstream of the Town of Minturn corporate limits. <br /> <br />Starting water-surface elevations for Fryingpan and Roaring Fork <br />Rivers were obtained from a flood study done on Fryingpan River <br />through the Town of Basalt (Reference 10). On Taylor Creek, the <br />starting water-surface elevations were taken from those elevations <br />calculated for Fryingpan River. <br /> <br />Starting water-surface elevations for Brush Creek, Reach 1, were <br />calculated using critical depth at the mouth of Brush Creek. Start- <br />ing water-surface elevations for the supercritical flow on Brush <br />Creek, Reach 2, were calculated using critical depth at the upstream <br />end of the reach. Starting water-surface elevations for Eagle River <br />(at Redcliff) were calculated using critical depth downstream of the <br />corporate limits of the Town of Redcliff. Turkey Creek starting <br />water-surface elevations were derived from the calculated flood <br />elevations on Eagle River (at Redcliff). <br /> <br />Flood profiles were drawn showing computed water-surface elevations <br />to an accuracy of 0.5 foot for floods of the selected recurrence <br />intervals. <br /> <br />The hydraulic analyses for this study were based on unobstructed <br />flow. The flood elevations shown on the profiles are, thus, con- <br />sidered valid only if hydraulic structures remain unobstructed, <br />operate properly, and do not fail. <br /> <br />11 <br /> <br />REVISEO: 1/25/83 <br />