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Chapter 4 - Best Mane merit Pracdces_for Erosion. and Sediment. Control r Block and gravel drop inlet sediment filter 1. Place concrete blocks lengthwise on their sides in a single row around the perimeter of the inlet, with the ends of adjacent blocks abutting. The height of the barrier can be varied, depending on design needs, by stacking combinations of 4 inch, 8 inch ` and 12 inch (101 20, and 30 cm) wide blocks. The barrier of blocks shallbeatleast 12 inches (30 cm) high andno greater than 24 inches (60 cm) high. ` 2, Wire mesh shall be placed over the outside vertical face (webbing) of the concrete blocks to.prevent stone from being washed through theholes in the blocks. Hardware cloth or comparable wire mesh with 1/2 inch (13 mm) openings shall be ' used. (See Plate 4.08g) N 3. Stone.shall.be piled against the wire to the tap of the block barrier. Suitable coarse aggregate shall be used. (See Plate 4.08h) 4. if the stone filter becomes clogged with sediment so that it no longer adequately performs its function, the stone must be pulled away from the blocks, cleaned and replaced. As a very temporary alternative, pervious burlap bags filled with gravel may be placed around the inlet provided that there are no gaps between the bags. (See Plate 4.08i) 6. Either of these two practices may be installed on pavement or bare ground ' Sod drop inlet sediment filter q . Sail shall be prepared and sod installed` according to the specifications in SODDING Section 6.67 (ES BMP 1.67). 2. Sod shall be placed to form a turf. mat covering the soil for a distance of 4 feet (1.2 m) from each side of the inlet structure. (See Plate 4.08j) Prefabricated drop inlet intemal filter baa (ACF Silt Sack) 1, Remove the grate over the catch basin and insert the filter device, then replace r grate to hold the device in position. 2. When sediments have accumulated to within one foot (30 cm) of the grate the filter insert must be removed by a front-end loader orforklift. The filter may be discarded ' and replaced or it may be emptied, cleaned, and reused. NOTE: This segment does not constitute a product endorsement.