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2.4 CULVERT DESIGNS <br />This section contains culvert design information for the D-Seam Portal, Pond D, Pond B, Hubbard Creek Fansite <br />and Bear Creek Fansite areas. All culverts are designed to safely pass the peak flow from the 10-year, 24-hour <br />storm event. Culverts DA and DA2 are designed to safely pass the peak flow from the 100-year, 24-hour storm <br />event. <br />The 100-year, 24-hour peak flow for Elk Creek is 107.0 cfs (using a conservative CN of GO)and "155.0 cfs for Bear <br />Creek (using a CN of 57). The methodology and assumptions used to determine the peak flow are included in <br />previously approved submittals (refer to Section 2) <br />Culverts for the D-Seam Portal, Pond D, and Pond B were sized using the U.S. Bureau of Public Roads <br />nomography. The culvert nomographs can be found in the culvert design section. The culverts were designed <br />assuming aheadwater/diameter ratio of 1.5 (unless otherwise specified). A summary of inputs and results are <br />shown on the following Tables. <br />Culverts HCC-1, HCC-2, HCC-3, and BCC-1 were sized using Sedcad and calculations are shown in Section 10. <br />Culvert inlet protection will consist of riprap extending to the highwater level (1.5 feet above the top of culvert). <br />Small sumps may be constructed at the entrances of culverts if OML.I,C determines no under-cutting will occur. <br />Straw bales will be placed up-stream of culvert entrances, when appropriate, to limit Flow velocities and to control <br />sediment. <br />