Laserfiche WebLink
III IIIIIIIIIIIII III <br />999 <br />~~ MINE AREA DIVERSIONS AND DITCHES Doc Date:121111zoo1 <br />• SEDIMENT COLLECTION DITCHES <br />The sediment collection ditches collect surface runoff from the facilities <br />area and the raw and clean coal stockpile areas and route it to <br />Sedimentation Pond No. 1 and Sedimentation Pond No. 5. The ditches are <br />designed to safely pass the peak discharge from the 5-year, 24-hour storm <br />event with exception of the Access Road Collection Ditch. It is designed <br />to safely pass the peak discharge from the 10-year, 24-hour storm event. <br />All sediment collection ditches are constructed as trapezoidal channels <br />with 2H:1V sideslopes. Specifically, there are two (2) sediment <br />collection ditches which exist within the Southfield facilities area: <br />o Collection Ditch No. 1 (CD-1) <br />o Collection Ditch N0. 2 (CD-2) <br />o Access Road Collection Ditch <br />Collection Ditch No. 1 (CD-1) <br />CD-1 is located along the northern edge of the facilities area just south <br />of County Road No. 92 as shown on the Drainage and Sediment Control Map, <br />(Map 20). The ditch routes the facilities area surface runoff to the yard <br />area catchment basin, where it is collected and routed via a 24-inch CMP <br />to the access road collection ditch as shown on the Drainage and Sediment <br />Control Map, (Map 20). The access road collection ditch empties to <br />Sedimentation Pond No. 5. <br />CD-1 is divided into three (3) sections (Sections A, B and C) each having <br />a different channel slope. The peak flow calculated for the 10-year, 24- <br />hour event is 4.51 cubic feet per second. <br />Section A has a channel slope of 5.0 percent and a flow velocity equal to <br />4.4 feet per second. Section B has a channel slope of 15.0 percent and a <br />flow velocity equal to 6.7 feet per second. Section C has a channel <br /> <br />C:\ W ORR\PRN6(~BbOfR I J. RE V <br />~,IIJ~J ~m 93R Revised - Apri 1 1993 <br />