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APPENDIX 2.05.3-66 <br />• SEDIMENT TRAP DESIGN - RECLAIMED BACKFILLED MINE AREA <br />SUN COAL COMPANY - MEADOWS N0. 1 <br />ROUTT COUNTY, COLORADO <br />• <br />• <br />Area C <br />Area = 6.5 acres <br />Change in elevation = 257 feet <br />Channel length = 1175 feet <br />CN number* = 75 <br />Precipitation* <br />100-year/24-hour - 2.3 inches <br />25-year/24-hour - 2.0 inches <br />10-year/24-hour - 1.6 inches <br />Runoff* <br />100-year/24-hour - 0.59 inches <br />25-year/24-hour - 0.38 inches <br />10-year/24-hour - 0.20 inches <br />Slope adjustment factor* = 1.04 for a slope of 21.9% <br />Equivalent drainage area* = 18.5 acres <br />Equivalent peak flow* = 25.5 cfs/in. of runoff for <br /> 18.5 acres <br />lculations: <br />Q 100 yr. = 25.5 ins (.59") = 15.1 cfs 18:5 (1.04) = 5.5 cfs <br />Q 25 yr. = 25.5 ins (.38") = 9.7 cfs 18 (1.04) = 3.5 cfs <br />Q 10 yr. = 25.5 ins (.20") = 5.1 cfs ~~ (1.04) = 1.9 cfs <br />* Source -USDA-SCS Technical Release No. 55 and Procedures for Determining Peak <br />Fiows in Colorado, March 1980. <br />- 252 - (Rev. 5/86) <br />