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<br />• <br />CERTIFICATION <br />I certify that the designs for drainage through the reclaimed topography at New Elk were reviewed <br />by me and found to reflect conservative, standard engineering practices. These designs were <br />performed with the software SEDCAD+ and reflect non-erosive passage of the 100-year 24-hour <br />storm of 4.2 inches through diversions which are armored with riprap in almost all cases. <br />Curve numbers were assigned to reflect conditions at initial reclamation in all areas except the Refuse <br />Disposal Area (RDA), where the area would be reclaimed before the pond was removed and final <br />drainage was installed. Undisturbed vegetation at the site is ponderosa pine-oak forest on the north <br />facing slopes and an oak juniper community on the south facing slopes. All natural, undisturbed soils <br />have a D hydrologic classification. Disturbed areas adjacent to the river were originally loams with <br />a B hydrologic classification. Curve numbers have been assigned a C classification reflecting limited <br />topsoil replacement. It is assumed that the railroad embankment will stay in place, and that its coarse <br />texture reflects an earthen material with an A hydrologic classification. <br />:Table 19-1: Curve Numbers utilized in lost-Mining Topography Drainage Calculations <br />Hydrologic Soil Curve <br />Description Classification Vegetative Community Number <br />Undisturbed, North Ponderosa Pine- Oak, 80% <br />Facing Slopes D Total Cover 72 <br />Undisturbed, South <br />Facing Slopes D Oak-Juniper, 50 % Total Cover 79 <br />Railroad Embankment A Hard Surface Dirt Road 74 <br />Newly Reclaimed <br />Alluvium C <br />Reclaimed RDA D <br />Fallow 91 <br />Dryland Pasture & Range, 60% 83 <br />Total Cover <br />The information contained herein is accurate to the best of my knowledee and belief. <br />• <br />