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• <br />DRAINAGE FACILITIES <br />The layout of drainage facilities, including the design points, disturbed area, <br />2-49 <br />culverts and ditches, are shown an Figure 2.2-3. As shown in Appendix N, pages 16- <br />39, 10-year peak flows from drainage basins for D- 1through D-16 are less than 23 cfs <br />when routed together at the pond. Designs for the ditches flowing into and out of the <br />pond are shown in Table 4.2-12. <br />Runoff volume from these drainage basins during the 10-year storm total 1.7 <br />acre-feet, as shown by the values in Appendix N, page 13. <br />2.4.4.1 Alternate Sediment Controls <br />The office area is to have runoff controlled by alternate means. Run-off from the <br />area will be filtered through a silt fence. The following table lists the length of the silt <br />fence. The 1.7-inch, 10-year event was used to size the sediment fences. <br />~- <br />- ° <br />rvr~ - akFlfs° ~ Le <br />is "t <br />~ <br />~ ~ <br /> <br />Office Area 0.35 16-feet <br />Calculations confirming the adequacy of these controls are contained in Appendix M. <br />Berms or ditches will be constructed to direct run-off into the silt fence. The <br />berms/ditches will form triangular ditches at least 0.7 feet deep with 1.5H:1V side <br />slopes. See Appendix M for ditch sizing calculations. <br /> <br />M`Clane Volume 1 12/07 <br />