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be a maximum of 6-feet. Posts shall consist of either: <br /> . Wood with dimensions of 2-inches by 2-inches wide min. and a 3-feet <br /> min. length.Wood posts shall be free of defects such as knots, splits, or <br /> gouges. <br /> . No. 6 steel rebar or larger. <br /> . ASTM A 120 steel pipe with a minimum diameter of 1-inch. <br /> . U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft. <br /> . Other steel posts having equivalent strength and bending resistance to <br /> the post sizes listed above. <br /> 11. Locate silt fences on contour as much as possible, except at the ends of the <br /> fence, where the fence shall be turned uphill such that the silt fence captures <br /> the runoff water and prevents water from flowing around the end of the fence. <br /> 12. If the fence must cross contours, with the exception of the ends of the fence, <br /> place gravel check dams perpendicular to the back of the fence to minimize <br /> concentrated flow and erosion. The slope of the fence line where contours <br /> must be crossed shall not be steeper than 3H:1 V. <br /> . Gravel check dams shall be approximately 1-foot deep at the back of <br /> the fence. Gravel check dams shall be continued perpendicular to the <br /> fence at the same elevation until the top of the check dam intercepts the <br /> ground surface behind the fence. <br /> . Gravel check dams shall consist of crushed surfacing base course, <br /> gravel backfill for walls, or shoulder ballast. Gravel check dams shall be <br /> located every 10 feet along the fence where the fence must cross con- <br /> tours. <br /> . Refer to Figure II-4.2.13 Silt Fence Installation by Slicing Method (p.374)for slicing <br /> method details. Silt fence installation using the slicing method specifications: <br /> 1. The base of both end posts must be at least 2-to 4-inches above the top of <br /> the filter fabric on the middle posts for ditch checks to drain properly. Use a <br /> hand level or string level, if necessary, to mark base points before install- <br /> ation. <br /> 2. Install posts 3-to 4-feet apart in critical retention areas and 6-to 7-feet apart <br /> in standard applications. <br /> 3. Install posts 24-inches deep on the downstream side of the silt fence, and as <br /> close as possible to the filter fabric, enabling posts to support the filter fabric <br /> from upstream water pressure. <br /> 4. Install posts with the nipples facing away from the filter fabric. <br /> 2014 Stormwater Management Manual for Western Washington <br /> Volume 11-Chapter 4 -Page 372 <br />