2009-05-12_PERMIT FILE - C1980005 (2)

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• 4.02.3(4)Drainaae. Each access road not within areas disturbed by minirxl and reclamation activities will be designed, ~ircted or reconstructed, aryl maintained to have adequate drainage using ditches and culverts to safely convey the peak runoff fr~n a 10-year, 24-hour precipitation event while maintaining a minimum of one foot of freeboard to the top of the road pmtanx,~+,t (see I~dri.bit 7-14 for typical details of drainage ~). 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 i.rl aocordailce with the raniirements of 4.03.1. Water fran a fill will be released below the fill thrax~r wnduits or >n adequately lined channels and will not be discharged onto the fill. • Fhien road duchess disctlarge onto open terrain, a number of measures will be taken to protect the terrain from erosion. Peabody will utilize measures as revegetation, riprap, straw dikes, and silt fence to protect the terrain fran erosion. 4h~en the road ditch discharges onto an area disturbed by road construction, the terrain 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 (straw dikes, wntairmpsit ditches, silt fences etc) will be employed while the area is undergoing revegetation such as straw dikes, containment ditches, etc. Peabody typically constructs ditches on the inside of roadway cuts for drainage. Atypical V~litch section would be a m; n;Trn m, of two feet deep with side slopes 2:1 or flatter. As most road cuts are into resistant bedrock-type material, ditches normally do not require linirxl. Culverts will be • designed and installed to minimize the runoff volume conveyed 12-37e Revised 08/20/93