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NOAA atlas for Colorado (Reference 4). Unit hydrographs used in this determination were calculated using procedures recommended by the Urban Drainage and Flood Control District, as is the official policy of the City of Pueblo. LoSS rates were calculated using scs curve numbers and a recent soil survey of the Pueblo area. All curve numbers were checked by an official of the SCS in Denver. The peak 100-year inflow to Lake Minnequa was calculated to be 3,400 cfs. The Lake Minnequa outflow hydro graph was developed using the HEC-l Modified pu1s routing method (Reference 12) with critical depth calculations at the outflow section. The stage-volume relationships were developed from previous work by Sellards and Grigg (Reference 13), the COE, and topographic mapping at a scale of 1:4,800, with a contour interval of 2 feet (Reference 14). The stage/volume/dis- charge curves developed by the study contractor are, therefore, similar to the previous COE and Sellards and Grigg curves. Assuming the lake to be at full stage during the 100-year flood event, the peak 100-year outflow discharge was found to be 2,400 cfs with a volume of 950 acre-feet. The 100-year elevation for Lake Minnequa is given in Table 3. The 10-, 50-, and SOO-year floods were not studied for this flooding source. 3.2 Hydraulic Analyses Analyses of the hydraulic characteristics of flooding from the sources studied were carried out to provide estimates of the eleva- tions of floods of the selected recurrence intervals. Water-surface elevations for the Arkansas River, Fountain Creek, Fountain Creek East Bank OVerflow, University Park Tributary, Wild Horse-Dry Creek, and the Bonforte Boulevard area were developed with the COE HEC-2 step-backwater computer program (Reference 15). Cross sections for the hydraulic analyses were obtained by photo- grammetric methods (Reference 16): from topographic maps at a scale of 1:1,200, with a contour interval of 2 feet (Reference 17): from a topographic map at a scale of 1:2,400, with a contour interval of 2 feet (Reference 18): from construction and grading plans for the University Park subdivision and Jerry Murphy Road (Reference 19): from grading plans for a borrow pit in Fountain Creek near the mouth of University Park Tributary (Reference 20); and from field surveys performed by the COE and the City of Pueblo. Locations of selected cross sections used in the hydraulic analyses are shown on the Flood Profiles (Exhibit 1). For stream segments for which a floodway was computed (Section 4.2), selected cross section locations are also shown on the Flood Boundary and F100dway Map (Exhibit 2). 17