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<br />-19- <br /> <br />comparative purposes. The spring snowmelt phenomena produces the peak <br />streamflow discharges for the main stem Gore Creek. The values derived <br /> <br />from the fourteen log-Normal snowmelt discharge probability analysis <br /> <br />were utilized in developing the Snowmelt Discharge curves, as pre~ <br /> <br />sented on Figures 111-7 to 1II-12. The curve fitting process included <br /> <br />a least squares computation for the best fit or mean discharge curve <br /> <br />and fitting an upper envelope curve based upon a 1.5 standard deviation. <br />The upper envelope'curve provides a confidence level of 93+% that <br />resultant peak discharges will fall below the curve. Due to the relative <br /> <br />shortness of many of the streamflow records. the upper envelope curve <br /> <br />was utilized in defining peak discharges for the floodplain compu- <br />tations in this study. <br />The 500 year snowmelt discharge curves were established by <br /> <br />extrapolating the curves for other recurrence intervals based upon a <br /> <br />criteria defined by the Colorado Water Conservation Board and in <br />accordancewithF.I.A.practices. Amore detailed discussion of the <br />procedures and the data are contained in the technical addendum to <br />this report. <br />Effects of Development on Discharges <br />Increased imperviousness within the Gore Creek Valley is not <br />expected to increase snowmelt flooding. This is because snow in the <br />lower valley will be melted early in the thaw before the creek is <br />near flood stage. 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