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General <br />All haul road ditches will be designed, constructed, and maintained to safely pass the <br />runoff from a 10-yea r, 24-hour precipitation event. All ditches will be constructed and <br />maintained to contain the minimum required cross sectional area for the designed runoff <br />volume. The minimum freeboard will be 0.5 feet above the normal depth. The locations of <br />the typi caL ditch section (A or B) ere shown on Exhibit 13-2 end typical section <br />dimensions are located on Exhibit 13-9. The typical section dimensions and type are <br />approximate for design calculations. The ditches in the field will be constructed and <br />maintained to ensure that the minimum cross sectional area is obtained for a particular <br />area. Listed below is a summary of the section properties for the typical ditch sections <br />and Tables 13-7.1 and 13-7.2 contain rating curves for these ditch sections. These <br />ditches will be utilized on A and B haul roads, ramps, and access roads. <br /> Section A B <br /> Type V V <br /> Side Slopes 3h:1v, 2h:1v 3h:1v, 3h:1v <br />• Nanning's N 0.035 0.035 <br /> 2 <br /> Nin. Flow Area (ft <br />) 10.0 2.5 <br /> Normal Depth (ft) 2.0 1.0 <br /> Nax. Capacity (cfs) 57 (0-2.5') 10 (0.1.5') <br /> 169 (3.0-3.5') 188 (2.0-3.5') <br />• <br />13-7-1 Revised 06/19/95 <br />