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The decommissioned road, where necessary, is ditched from the reclaimed • ~ area to the Yampa River. Ditches are located to convey surface water from the road to riprapped runouts prior to discharging to drainage basins outside of the permit area. The ditches are at least 18 inches deep and are at least 4 feet wide. The ditches are designed to convey the peak runoff from the 10-year, 24-hour storm and are adequately riprapped with rock (up to 6 inches) in order to minimize erosion. A recently constructed sedimentation pond (October 1983) is located adja- cent to the Yampa River to control runoff and erosion from the area occupied by the access road, the crusher, and the conveyor. The sedimentation pond replaces a reclaimed sedimentation pond where the new pond is designed with a capacity of .05 acre-feet and has an 18-inch CMP discharge pipe which serves as the emergency and principal spillway for the small structure (Appendix 2.05.3-3). The pond • has a freeboard in excess of one foot and is designed to contain the peak flow from the 10-year, 24-hour storm event and is designed to safely convey, through the spillway, the peak flow from the 25-year, 24-hour storm event. The dis- turbed area draining into the structure has been graded to direct water into the structure; and, where necessary, a berm has been constructed around the dis- turbed area to minimize erosion and potential sedimentation entering the Yampa River. The sediment pond has a combined upstream and downstream sideslope of not less than 1 vertical and 5 horizontal, with neither slope steeper than lv:2h. The structure was constructed with non-alluvial material containing no organic matter, frozen soil, or mine waste material. Material used in construction was compacted with a dozer during impoundment construction. The side of the pond near the river was riprapped to protect the berm from the river; and, where the - l77 - (Rev. 5/86)