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<br />• 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 />2. Another ditch will be constructed along the western peri- <br />meter of the laydown area. This ditch was designed using <br />Manning`s equation for a triangular channel as follows: <br />Design discharge 2.6 cfs <br />Design slope = 4.7% <br />Manning's n ~ 0.03 <br />Freeboard = 0.5 ft. <br />Normal depth = 0.42 ft, <br />Side slope 3 to 1 <br />Channel depth 1.0 ft. <br />Top width (with freeboard) ~ 6 ft. <br />Design velocity = 3.6 ft./sec. <br />3. The sediment pond proposed for sediment control at the <br />northwest corner of the laydown area is approximately <br />triangular in shape with a 150 ft. base and two 100 ft. <br />sides. <br />The. average depth will exceed 5 feet. A berm will be <br />c.onstrucxed to achieve this depth using excavated mate- <br />rial. Pond embankments will be constructed in accordance <br />with Section 4..05.6(8) of the Regulations of the Colorado <br />Mined Land Reclamation Board for Coal Mining and compac- <br />ted to ASTM Method D698 Standard Proctor Density of 90%. <br />The pond will provide more than 95% removal of sediment <br />larger than 0.05 mm in size. The pond will be sized to <br />store the runoff from a 10 year, 24 hour, precipitation <br />D-4 <br />