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The drill road has 0.2 acres of disturbance, 18.8 acres of contributing watershed, and a ground <br />slope for the contributing watershed of 11 %. A curve number of 85 was utilized to reflect the <br />disturbed condition of the drill road and a curve number of 63 was used to reflect the undisturbed <br />condition of the contributing watershed. <br />This demonstration utilized the Manning's roughness coefficient of 0.0054, and a stem spacing <br />of 0.86 inches. These inputs are intended to reflect that the native grass cover density adjacent to <br />the drill roads. The 0.13 cfs flow was then run through a native grass filter approximately 692 <br />feet in length (road length) and 10 feet in width (direction of the flow through the grass filter). <br />As shown in the attached SEDCAD output files, the calculated resulting peak settleable <br />concentration released and the 24 -hr weighted settleable solids concentration is 0.00 ml/1, well <br />below the effluent standards of 0.5 ml/1, and a 97.1 % trap efficiency. <br />Exh. 7, Item 14, Page 2 Revision Date: 5/22/17 <br />Revision No.: MR -174 <br />