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<br />The annual peak discharges were obtained from USGS Water-Supply Paper <br />Nos. 1681, 1921, and 2121 (References 8, 9, and 10, respectively) and <br />from Water Resources Data for Colorado (Reference 11). Regional <br />relationships of basin area to peak discharge were determined for the <br />10-, 50-, 100-, and 500-year floods (Reference 3). Previously, the <br />COE, Albuquerque District, computed frequency-discharge curves from <br />gage station analyses of the USGS gages on the Arkansas River at Pueblo <br />and Canon City (Reference 1). An area proportion was then applied <br />between the Pueblo and Canon City station results to obtain peak flows <br />in Fremont County. The discharges obtained in the previous <br />calculations fell within the 90 percent confidence limits of the COE <br />Canon City gage-station-analyses discharges; therefore, the hydrologic <br />analyses performed by the COE are considered valid. <br /> <br />There are no streamflow records for the NE Canon drainage basin. Peak <br />discharges for the 100-year frequency flood were therefore developed <br />using the synthetic rainfall-runoff evaluation procedures <br />(Reference 12). Synthetic runoff hydro graphs were developed from the <br />U.S. Soil Conservation Service Triangular Hydrograph Equation using <br />incremental hydrographs. All runoff computations were based on <br />existing land use and cover conditions in the watershed as of March <br />1980. Precipitation data were taken from NOAA Atlas #2, <br />Precipitation-Frequency Atlas of the Western United States, Volume III, <br />Colorado, (Reference 13). <br /> <br />Peak discharge-drainage area relationships for Arkansas <br />Coal, and Chandler Creeks, and NE Canon Drainage Area <br />Table. 1. <br /> <br />Ri ver, Oak, <br />are shown in <br /> <br /> TABLE 1 - SUMMARY OF DISCHARGES <br />FLOODING SOURCES DRAINAGE AREA PEAK DISCHARGE (cfs) <br />AND LOCATION (Sq Miles) 10-YEAR 50-YEAR 100-YEAR 500-YEAR <br />Arkansas River <br />Upstream of Florence <br /> At Minnequa Dam 3,546 11,000 21,000 28,000 71,000 <br /> At Canon city 3,117 8,850 16,500 20,500 32,500 <br />Oak Creek At Mouth 72.0 7,100 13,300 16,000 23,000 <br />Coal Creek At Mouth 20.40 4,900 7,800 9,000 15,000 <br />NE Canon Drainage Area <br />North of Kountz Avenue 5.53 --1 --1 2,380 --1 <br />North of Central 4.75 --1 --1 1,660 --1 <br />South of South Street 3.17 --1 --1 1,450 --1 <br />South of High Street 2.68 --1 --1 1,050 --1 <br />North of High Street <br /> (Sub-basin from NW) 1. 67 --1 --1 630 --1 <br />North of Harding 1.58 --1 --1 850 --1 <br />North of High Street <br /> (Sub-basin from NE) 1. 01 --1 --1 926 --1 <br />Chandler Creek At Mouth 13.95 6,200 8,200 12,500 20,000 <br />--1 Not Computed <br /> <br />6 <br />