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• safely convey the peak runoff from a 10-year, 24-hour precipitation event while maintaining a <br />minimum of one half foot of freeboard to the top of the road embankment (see Map 2.05.3-2 for <br />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 area <br />will be revegetated to control runoff. In an area where revegetation would not be sufficient to <br />control erosion, the area will be rip-rapped. Temporary measures to reduce erosion will be <br />employed while the area is undergoing revegetation such as straw dikes, containment ditches, <br />etc. WFC typically constructs ditches on the inside of roadway cuts and safety berms for <br />drainage. As most road cuts are into resistant bedrock-type material, ditches normally do not <br />require lining. Culvert designs are presented in the previous section. <br />If the ditch is not stable, then WFC will use a larger ditch section and/or adequately line the ditch <br />in order to comply with applicable regulations. <br />Maintenance Same as for original haul roads. See Section 2.05.3. <br />Restoration Same as for original haul roads. See Section 2.05.3 <br />Access Roads and Light Use Roads in Amendment Area No major access roads will be used <br />for the amendment area although minor access to sediment ponds and other facilities may be <br />used at various times. These roads will follow the same design and installation procedures as <br />outlined in Section 2.05.3 for the original mine permit area. <br />Support Facilities-Buildings No new buildings are planned within the amendment area. <br />Coal Handling Structures No new coal handling structures are planned within the amendment <br />area. <br />Support Facilities and Utility Installations. No new support facilities will be located within the <br />amendment area. <br />• <br />(Revised 12/00) Attachment 2.05.3(3) -10-101 <br />