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General <br />All haul road ditches will be designed, constructed and maintained to <br />safely pass the runoff from a 10 year-24 hour precipitation event. All <br />ditches will be constructed and maintained to contain the minimum required <br />cross sectional area for the designed runoff volume. The minimum <br />freeboard will be 0.3 feet above the normal depth. The locations of the <br />typical ditch sections (A, B, or D) are shown on Exhibit 7-7 and typical <br />section dimensions are located on Exhibit 7-14. The typical dimensions <br />are approximate and the ditches in the field will be maintained to ensure <br />that the minimum cross sectional area is obtained for a particular area. <br />Listed below is a summary of the section properties for the typical ditch <br />sections and Table 7-6-4-1 and Figure 7-6-4-1 contain rating curves for <br />these ditch sections. <br />Section A 8 D <br />Shape V V V <br />• Side Slopes 3h:ly 3h:ly 3h:ly <br />Manning's N 0.035 0.035 0.035 <br />Min. Flow Area (ftz) 27.0 12.0 3.0 <br />Max. Capacity (cfs) 145.1 49.2 7.8 <br />Normal Depth (ft) 3.0 2.0 1.0 <br /> <br />7-6-4-2 <br />