Sheet flow runoff from denuded areas shall be intercepted by silt fence or diversions to protect adjacent properties and water resources from sediment transported via sheet flow.
(a) Where intended to provide sediment control, silt fence shall be placed on a level contour and not placed where concentrated flow is directed toward it. Silt fence shall be pulled tight and trenched at least four inches to six inches into the ground and backfilled to prevent runoff from cutting underneath the fence. Sections of silt fence shall be joined so there are no gaps in the fence. The ends of the silt fence shall be brought upslope of the rest of the fence to prevent runoff from going around the ends. Silt fence shall not control large drainage areas. The relationship between the maximum drainage area to silt fence for a particular slope range is shown in the table below.
TABLE 5: MAXIMUM DRAINAGE AREA TO SILT FENCE
Maximum Drainage Area (in acres) to 100 Linear Feet of Silt Fence | Range of Slope for a Particular Drainage Area (in percent) |
0.5 | <2% |
0.25 | 2% but < |
1.125 | 20% but < 50% |
(b) The use of combination barrier constructed of silt fence supported by straw bales or silt fence embedded within rock check dams may be effective for use in roadside ditches and on-site diversion swales and ditches. Storm water diversion practices shall be used to keep runoff away from disturbed areas and steep slopes where practicable. Such devices, which include swales, dikes or berms, may receive storm water runoff from areas up to ten acres.
(Ord. 15-O-2820, passed 5-19-2015)