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<br />that the results are reasonable. The fact that 21 additional years of peak flow data are now <br />available also increases confidence in the results of the current study. <br /> <br />For the Roaring Fork and Fryingpan Rivers, the hydrologic analyses were completed by the <br />USACE (Reference 17). A regional analysis of stream data taken at gages in the Roaring Fork <br />Basin was performed and natural flow frequency curves were developed. The peak flows <br />determined for the 10-,50-, 100-, and 500-year floods were used to determine the flood profiles <br />and the 100-year floodplain for this report. <br /> <br />Data from a large number of stream gaging stations located within the homogenous watershed <br />area similar to this area were analyzed. These gages are located within Pitkin County and nearby <br />Summit, Eagle, Garfield, Mesa, Delta, and Gunnson Counties. The streamflow data were <br />separated into snowmelt and rainfall peaks and analyzed separately. <br /> <br />Snowmelt peaks from a total of 40 gages and rainfall peaks from 25 gages were analyzed to <br />obtain individual and regional statistical parameters of mean, standard deviation, and skew for <br />the two types of flow peaks. In numerous instances, the rainfall peaks were of very small <br />magnitude. Several stream gages did not show any significant peaks caused by rainfall. <br /> <br />Using log-Pearson Type ill distribution as described in U.S. Water Resources Council <br />Bulletin 17 A, the discharge-frequency information was developed separately for the snowmelt <br />peaks and the rainfall peaks for the 10-, 50-, 100-, and 500-year recurrence intervals. These two <br />distributions were combined to obtain the overall peak discharge-frequency relationship for each <br />stream. For ungaged streams, the values of regional statistical parameters were used and the <br />drainage area curves were developed for the 10-, 50-, 100-, 500-year recurrence intervals. <br /> <br />Peak discharges for the Roaring Fork and Fryingpan Rivers are shown in Table I. <br /> <br />21 <br />