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Chapter 4 - Best Management Practices for Erosion and Sediment Control <br /> Block and gravel drop inlet sediment filter <br /> r 1 . Place concrete blocks lengthwise on their sides in a single row around the perimeter <br /> of the inlet, with the ends of adjacent blocks abutting . The height of the barrier can <br /> be varied, depending on design needs, by stacking combinations of 4 inch , 8 inch <br /> and 12 inch ( 10 , 20 , and 30 cm) wide blocks . The barrier of blocks shall beatleast <br /> r 12 inches (30 cm) high and no greater than 24 inches (60 cm) high . <br /> 2 . Wire mesh shall be placed over the outside vertical face (webbing) of the concrete <br /> r blocks to prevent stone from being washed through the holes in the blocks . <br /> Hardware cloth or comparable wire mesh with 112 inch ( 13 mm) openings shall be <br />_ used . (See Plate 4. 08g) <br /> 3 . Stone shall be piled against the wire to the top of the block barrier. Suitable coarse <br />_ aggregate shall be used . (See Plate 4. 08h) <br /> 4 . If the stone filter becomes clogged with sediment so that it no longer adequately <br /> performs its function , the stone must be pulled away from the blocks , cleaned and <br /> replaced . <br /> 5 . As a very temporary alternative , pervious burlap bags filled with gravel may be <br /> r placed around the inlet provided that there are no gaps between the bags. (See <br /> Plate 4 .081) <br /> r 6 . Either of these two practices may be installed on pavement or bare ground <br /> Sod drop inlet sediment filter <br /> r <br /> 1 . Soil shall be prepared and sod installed according to the specifications in SODDING <br /> - Section 6 . 67 ( ES BMP 1 . 67) . <br /> 2 . Sod shall be placed to form a turf mat covering the soil for a distance of 4 feet <br /> ( 1 .2 m) from each side of the inlet structure . (See Plate 4 . 08j) <br /> r <br /> Prefabricated drop inlet internal filter bag (ACF Silt Sack) <br />.. 1 . Remove the grate over the catch basin and insert the filter device, then replace <br /> grate to hold the device in position . <br />.. 2 . When sediments have accumulated to within one foot (30 cm) of the grate the filter <br /> insert must be removed by a front-end loader or forklift. The filter may be discarded <br /> and replaced or it may be emptied , cleaned , and reused . <br /> NOTE: This segment does not constitute a product endorsement. <br /> 4-41 <br />