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density or as directed by the engineer to ensure that the embankment is adequate to support <br />the anticipated volume of traffic and weight and speed of vehicles to be used. <br />Material will be placed in an embankment only when its moisture content is within acceptable <br />levels to achieve design compaction. <br />Temporary erosion control measures (ditches, berms, straw dikes, silt fence) will be utilized <br />during embankment construction to minimize sedimentation and erosion until permanent <br />control measures can be established. Immediately upon completion, measures will be taken <br />to stabilize all embankments with vegetation cover or other means as approved by the <br />regulatory authority to minimize erosion. Where a vegetation cover is used, consideration <br />shall be given to providing an appropriate growth medium. <br />Drainage Each haul road not within areas disturbed by mining and reclamation activities wil <br />be designed, constructed and maintained to have adequate drainage using ditches and <br />culverts to safely convey the peak runoff from a 10 -year, 24 -hour precipitation event while <br />maintaining a minimum of one half foot of freeboard to the top of the road embankment (see <br />Map 2.05.3(3) -1 for typical details of drainage structures). <br />Drainage ditches will be placed at the toe of all cut slopes formed by the construction of haul <br />roads. Water will be intercepted before reaching a large fill and drained safely away in <br />accordance with the requirements of 4.03.1. Water from a fill will be released below the fill <br />through conduits or in adequately lined channels and will not be discharged onto the fill. <br />When drainage ditches discharge onto open terrain, a number of measures will be taken to <br />protect the terrain from erosion. When the drainage discharges onto a disturbed area, the <br />area will be revegetated to control runoff. In an area where revegetation would not be <br />sufficient to control erosion, the area will be rip- rapped. Temporary measures to reduce <br />erosion will be employed while the area is undergoing revegetation such as straw dikes, <br />containment ditches, etc. WFC typically constructs ditches on the inside of roadway cuts <br />and safety berms for drainage. As most road cuts are into resistant bedrock -type material, <br />ditches normally do not require lining. Culverts will be designed and installed to minimize the <br />runoff volume conveyed in each ditch. Culverts and ditches will typically be designed using <br />SEDCAD or other generally accepted software to predict the peak runoff and Manning's <br />equation to determine the peak velocity and flow depth. <br />Revised June 2010 (PR06) 2.05.3(3) -23 <br />