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i Chapter 4 - Best Management Practices for Erosion and Sediment Control i Design Criteria w A formal design is not required for many small projects and for minor or incidental applications . For larger projects refer to Figure 4 . 05a (FDOT Standard Index 102, Chart 1 ) for guidance on recommended spacing . w Construction Specifications .. Sheet Flow Applications 1 . Bales shall be placed in a single row, lengthwise on the contour, with ends of i adjacent bales tightly abutting each other. 2 . All bales shall be either wire-bound or string-tied . Straw bales shall be installed so that bindings are oriented around the sides rather than along the tops and bottoms of the bales (in order to prevent deterioration of the bindings) . (See Plate 4 . 05b) 3 . The barrier shall be entrenched and backfilled . A trench shall be excavated the width of a bale and the length of the proposed barrier to a minimum depth of 4 inches ( 10 cm) . After the bales are staked and chinked , the excavated soil shall be backfilled against the barrier. Backfill soil shall conform to the ground level on the downhill side and shall be built up to 4 inches ( 10 cm) against the uphill side of the i barrier (See Plate 4 . 05c) 4 . Each bale shall be securely anchored by at least two 2" x 2" (5 cm x 5 cm) minimum wooden stakes or two #5 ( 16 mm) minimum rebars at least 3 feet (0 .9 m) i driven through the bale . The first stake in each bale shall be driven toward the previously laid bale to force the bales together. Stakes or rebars shall be driven deep enough into the ground to securely anchor the bales. Straw bale barriers i placed on paved surfaces may be secured by placing heavy sand bags on top, and/or by bracing with 2 x 4's (5 x 10 cm) . (See Plate 4 . 05d) 5 . The gaps between bales shall be chinked (filled by wedging) with straw to prevent water from escaping between the bales. (See Plate 4 . 05b) loose straw scattered over the area immediately uphill from a straw bale barrier tends to " increase barrier efficiency . 6 . When bales are installed at the toe of a slope , they should be placed away from the slope for increased storage capacity. (See Plate 4 .05e) 7 . Inspection shall be frequent and repair or replacement shall be made promptly as needed . 8 . Straw bale barriers shall be removed when they have served their usefulness , but " not before the upslope areas have been permanently stabilized . +� 4-17