1988-04-11_PERMIT FILE - C1981008A (20)

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Each layer of the embankment will be completed, leveled and compacted before the succeeding layer is placed. Successive layers will be compacted evenly by routing dozers, trucks and scrapers over the entire width of the embankment. This procedure will be continued until no visible horizontal movement of the embankment material is apparent. Embankment layers will be compacted to a minimum of 90 percent of Standard Proctor density or as directed by the engineer to ensure that the embankment is adequate to support the anticipated volume of traffic and weight and speed of vehicles to be used. Material will be placed in an embankment only when its moisture content is within acceptable levels to achieve design compaction. Temporary erosion control measures (ditches, berms, straw dikes, silt fence) will be utilized during embankment construction to minimize sedimentation and erosion until permanent control measures can be established. Immediately upon completion, measures will be taken to stabilize all embankments with vegetation cover or other means as approved by the regulatory authority to minimize erosion. Where a vegetation cover is used, consideration shall be given to providing an appropriate growth medium. Drainage. Each access road not within areas disturbed by mining and reclamation activities will be designed, constructed and maintained to have adequate drainage using ditches and culverts to safely convey the peak runoff from a 10-year, 24-hour precipitation event while maintaining a minimum of one foot of freeboard to the top of the road embankment (see Exhibit 13-20 for typical details of drainage structures). Drainage ditches will be placed at the toe of all cut slopes formed by the construction of haul roads. Water will be intercepted before reaching a large fill and drained safely away in accordance with the requirements of 4.03.1. Water from a fill will be released below the fill through conduits or in adequately lined channels and will not be discharged onto the fill. When drainage ditches discharge onto open terrain, a number of measures will be taken to protect the terrain from erosion. When the drainage discharges onto a disturbed area, the area will be revegetated to control runoff. In an area where revegetation would not be sufficient to control erosion, the area will be riprapped. Temporary measures to reduce erosion will be employed while the area is undergoing revegetation such as straw dikes, containment ditches, etc. 13-26 Revised 04/11/88