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requirements of 4.03.1. Water from a fill will be released below the till through conduits or in <br />adequately lined channels and will not be discharged onto the fill. <br />When haul road drainage ditches discharge onto open terrain, a number of measures will be taken to <br />minimize erosion including revegetation, straw dikes, and riprap. When the road ditch discharges onto <br />a disturbed area, the terrain will be revegetated or riprapped, if necessary, to control runoff and erosion. <br />Temporary measures to reduce erosion (straw dikes, containment ditches, silt fence, etc.) will be <br />employed while the area is undergoing revegetation. <br />SCC typically constructs ditches on the inside of roadway cuts and safety berms for drainage. A <br />typical V-ditch section would be a minimum of two feet deep with side slopes 1.5:1 or flatter. As <br />most road cuts are into resistant bedrock-type material, ditches normally do not require lining. Culverts <br />will be sized and installed to minimize the runoff volume conveyed in each ditch. Culverts and ditches <br />will typically be designed using SEDCAD+ to predict the peak runoff and Manning's equation to <br />determine the peak velocity and flow depth Isee Attachment 13-11. Tables 13-3 and 13-4 contains an <br />inventory of existing and proposed ditches at the Seneca II-W Mine while Attachment 13-6 contains <br />the design calculations for existing and proposed typical ditches. Haul Roads G, H, I, J, K, and L will <br />utilize typical ditch cross sections as depicted on Exhibit 13-10 and located on Exhibits 13-2 and 13- <br />2A. Attachment 13-fiA contains general designs for the porous rock check dams in the Mine Entrance <br />Road and Haul Road G ditches. These check dams assist in minimizing the amount of sediment • <br />reaching some of the culvert outlets along these roads. <br />Ii the ditch is not stable, then a larger ditch section will be used and/or adequately lined in order to <br />comply with applicable regulations. <br />Drainage from haul roads within the areas disturbed by mining and reclamation activities Isee Exhibits <br />13-2 and 13-2A1 will be constructed to meet the requirements of 4.05.2 and such haul roads will at a <br />minimum be constructed and maintained to minimize erosion of the disturbed area. Erosion control <br />measures to be used singly or in combination include but are not limited to: <br />a. Stabilizing all exposed surface areas to promote a reduction in the rate and volume of <br />runoff; <br />b. Using straw dikes, riprap, check dams, berms, geotextile materials, mulches, vegetation <br />sediment filters, contour turrows or other measures that reduce overland Tlow velocity, <br />reduce runoff volume, or trap sediment; or <br />c. Such other measures to minimize erosion resultant siltation and disturbance to the prevailing <br />hydrological balance. <br />Surfacing. See Exhibit 13-10 for typical detail. <br />f 1 <br />~J <br />18 Revised 4/01 <br />