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Chapter V <br /> • Rolling Dips. Rolling dips may be used as cross-drainage structures. Dips should be <br /> constructed so that the drainage bottom slopes gently downward from the toe of the <br /> road cut to the shoulder of the fill. These may be used in preference to, or as a <br /> replacement for, culverts. <br /> B.A.T. Ponds. B.A.T. ponds are/may be constructed to allow for enhanced sediment <br /> control without creating undue and counterproductive surface disturbance. Design, <br /> size and construction methods are determined by considerations of available space <br /> and intended function. <br /> B.A.T. ponds have been constructed at the base of a steep slope below Road D, <br /> 110+00 - 100+00, an area of heavy snow and avalanching, to intercept overland flows <br /> without sustaining snow damage. B.A.T. ponds at the base of Road D, above the Arctic <br /> Circle, intercept substantial amounts of sediment from flows down the road ditch, but <br /> conform to the available space and terrain. <br /> Vegetation. Mid-Continent hydro-mulched substantial portions of the cut slopes on the <br /> roads, with assistance from the U.S.Forest Service, and planted thousands of trees <br /> during the 1970s and 1980s. <br /> C.S. Coal has identified additional cut slopes which will be planted with a quick-growing <br /> • seed mix intended to achieve interim stabilization and prevent loss of sediment. <br /> Substantial portions of the roads will be ripped and seeded at out-turns and along the <br /> outside portion of the road bed. The roadbeds themselves do not have the steep <br /> gradient and slope creep which hinders establishment of vegetation on the fill slopes, <br /> and once established, will provide a good vegetative buffer to control erosion. <br /> Vegetation is naturally establishing along segments of Road G, and elsewhere. In <br /> some areas, natural growth will be supplemented with the interim seed mix. <br /> A seed mix approved by the Division will be used for interim road stabilization. <br /> Check Dam Structures. Check dam structures will be keyed into gullied areas which <br /> have formed below drainage ditch outlets and culvert outfalls. Generally, these are <br /> found in steep, forested terrain which is inaccessible to equipment. Available on-site <br /> rock and timber will be used with the objective of slowing flow velocities, and to allow <br /> the gullies to stabilize to the extent possible. <br /> Straw Bale Check Dams. These are readily employed, easily transported, and provide <br /> good sediment control for small, limited areas. When installed on steep slopes, the <br /> dams are generally staked into the ground with roof bolts. <br /> • d. Portal Benches <br /> 19 <br /> Revised 7/92 <br />