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3.7 <br />2. Spreader lip: Construct the spreader lip in undisturbed soil. Construct the lip to <br />uniform height, at least 6 inches above the base of the spreader, and 0% grade over <br />the length of the spreader. <br />3. Gravel berm: Place a 6 -inch high gravel berm across the level lip. Gravel placed on <br />the level lip shall consist of washed crushed rock, 2 -inch maximum in size. <br />4. Length: Establish the spreader length based on flow expected from the ditch as <br />indicated on Table 02210-1: <br />TABLE 02210-1 <br />DITCH FLOW VS. MINIMUM SPREADER LENGTH <br />Ditch Flow ( m) <br />Minimum Spreader Length (ft) <br />< 50 <br />15 <br />50-100 <br />20 <br />100-130 <br />30 <br />130-180 <br />40 <br />5. Width: 6 feet minimum <br />TEMPORARY SEDIMENT TRAP <br />A. Temporary sediment traps may be used to collect and store sediment under the following <br />conditions: <br />1. Where drainage area above sediment trap is less than 3 acres. <br />2. At the outlets of diversion channels that convey sediment -laden water. <br />3. Where access can be maintained for sediment removal. <br />B. Sediment traps may be formed completely by excavation or by construction of compacted <br />embankment dikes. Construct temporary sediment traps in accordance with the <br />following: <br />1. Dike embankment: <br />Height: 5 feet maximum <br />Top Width: 4 feet minimum <br />Side Slopes: 3H:1 V or flatter <br />Materials: Suitable materials for embankment are locally -derived soils, free <br />of rocks larger than 6 -inches, debris, waste, frozen materials, <br />vegetation, and other deleterious materials. <br />Placement: Clear, grub and strip the embankment footprint area of all <br />vegetation and topsoil. Place embankment fill material in lifts not <br />exceeding 9 -inches loose thickness and compact to at least 92 <br />percent maximum dry density in accordance with ASTM D698. <br />2. Excavation: Where sediment traps are formed by excavation, keep side slopes 2H:1 V <br />or flatter. <br />Erosion and Sediment Controls February 2017 02210-5 <br />