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Volume V -Appendix M(viii) <br />Small Area Exemption No. 1 -SAE-4 <br />Calculation Rational and Results Summary <br />Silt Fence Design <br />Topsoil Area -Munger Canyon Mine <br />Purpose: <br />To control the runoff of water and sediment from the topsoil site, after final reclamation, a <br />silt fence was designed. The silt fence will be installed to the East of where the 72" <br />culvert on the haul road is located as shown on Page M(viii)-iii. <br />Rational: <br />Calculated using SEDCADr"' 4 for Windows <br />The landslope used in SEDCAD 3.5% and as such, berms will be constructed at a 3.5% <br />grade on both sides of the fence in order to direct the runoff to the fence. The fence will <br />be placed at the lowest elevation point as shown on Page M(viii)-iii. <br />Areas, slopes and flow paths obtained from the Sketch on following page M(viii)3ii. <br />The soil type in the study area is very gravelly clay loam <br />The following Curve Numbers were utilized in the calculations: <br />Reclaimed Topsoil Area - 87 - C soil group, Herbaceous Mixture poor cover <br />Table 2-2d Runoff curve numbers for arid and semiarid rangelands <br />10 year 24 hour storm event of 1.5" used in calculations to be conservative. <br />ENGINEER'S CERTIFICATION <br />The SEDCAD calculations and inforr~~~esented orb pages M(viii)-3i and M(viii)-iii were <br />prepared under my direct superva~~q@@"II~nontli~f May 2007, and the information <br />presented is true and correct tgt _,FitystEo~ ~Sfcttledge and belief. <br />Date <br />State of <br />I~ <br />M(viii)-3 <br />05/07 <br />