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Freeboard = 0.5 ft. <br />Normal depth = 0.4 ft. <br />Side slope = 4 to 1 <br />Depth (with freeboard) = 1.0 ft. <br />Top width (with freeboard) = 8 ft. <br />Design velocity = 3.9 ft./sec. <br /> <br />• <br />2. Another ditch will be constructed along the western perimeter <br />of the laydown area. This ditch was designed using Manning's <br />equation for a triangular channel as follows: <br />Design discharge <br />Design slope <br />Manning's n <br />Freeboard <br />Normal depth <br />Side slope <br />Channel depth <br />Top width (with freeboard) <br />Design velocity <br />= 2.6 cfs <br />= 4.7X <br />= 0.03 <br />= 0.5 ft. <br />= 0.42 ft. <br />= 3 t o 1 <br />= 1.0 ft. <br />= 6 ft. <br />= 3.6 ft./sec. <br />3. The sediment pond proposed for sediment control at the north- <br />west corner of the laydown area is approximately triangular <br />in shape with a 220 ft. base, one 175 ft. side and another <br />100 ft. side. <br />The average depth of the pond below the spillway invert is <br />about 2.7 ft. A berm will be constructed to achieve this <br />depth using excavated material. Pond embankments will be <br />constructed in accordance with Section 4.05.6(8) of the Regu- <br />lations of the Colorado Mined Land Reclamation Board for Coal <br />Mining and compacted to ASTM Method D698 Standard Proctor <br />Density of 90X. Maximum height of the embankment is 7.5 ft. <br />as measured from the upstream toe of the embankment. Accord- <br />ingly, the top width shall exceed 8.5 ft. in order to comply <br />D-4 <br />