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I <br />1 <br />1 <br />1 <br />Chute Spillway of Rubble <br />An overfall structure of rubble is applicable where it is <br />desirable to drop the watercourse elevation over a very short <br />horizontal distance. The spillway outlet should be designed so <br />that its function or stability will not be reduced by scour of <br />deposits in the exit channel. Generally chutes are designed in <br />conjunction with other erosion control practices to handle peak <br />storm flows. Rubble size is based on water velocity to be <br />withstood. <br />Sediment Control Basin with Rubble Spillway <br />This is a barrier or dam constructed across a watercourse or <br />gully to form a silt or sediment trap. Its purpose is to reduce <br />erosion from activity sites. The rubble spillway must be <br />designed to convey expected peak runoff. Basin sediment storage <br />capacity should not exceed two acre -feet and basin capacity <br />should be maintained at 50% (or greater) of original volume by <br />cleaning out as needed. A minimum embankment width of ten feet <br />is required for dams less than ten feet high, twelve feet for <br />dams exceeding ten feet. <br />Surface Roughening <br />' Providing a rough soil surface with horizontal depressions <br />created by operating a tillage or other suitable implement on the <br />contour, or by leaving slopes in a roughened condition by not <br />fine - grading them. The practice aids in establishment of <br />t vegetative cover with seed, reduces runoff velocity and increases <br />infiltration, and reduces erosion and provides for sediment <br />trapping. <br />' Grooving Slopes <br />' Grooving is cutting furrows along the contour of a slope. <br />Irregularities in the soil surface catch rainwater and provide <br />some coverage of lime, fertilizer, and seed. <br />' Level Spreader <br />' E -3 <br />An outlet <br />for dikes and <br />diversions consisting of an excavated <br />depression <br />constructed <br />at zero grade across a slope. The level <br />' <br />spreader <br />is to convert concentrated point runoff back to <br />dispersed <br />sheet flows <br />and release it onto areas stabilized by <br />existing vegetation. <br />1 <br />' E -3 <br />