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Florida Erosion and Sediment Control Inspector's Manual <br /> 4 . 05 STRAW BALE BARRIER <br /> ( ES BMP 1 . 05 ) <br /> .. Definition <br /> A temporary sediment barrier consisting of a row of entrenched and anchored straw bales . <br /> Purposes <br /> 1 . To intercept and detain small amounts of sediment from disturbed areas of limited <br /> extent. <br /> AW 2 . To decrease the velocity of sheet flows and low-to-moderate level channel flows . <br /> Conditions Where Practice Applies <br /> 1 . Below disturbed areas subject to sheet and rill erosion . <br /> 2 . Where the size of the drainage area is no greater than 1 /4 acre per 100 feet ( 1 . 3 <br /> ha/100 m ) of barrier length ; the maximum slope length behind the barrier is 100 feet <br /> (30 m ) ; and the maximum slope gradient behind the barrier is 50 percent (2 : 1 ) . <br /> 3 . In minor swales or ditch lines where the maximum contributing drainage area is <br /> no greater than 2 acres (0 . 8 ha ) . <br /> 4 . Where effectiveness is required for less than 3 months. <br />'s 5 . Under no circumstances should straw bale barriers be constructed in streams or in <br /> swales where there is a possibility of a washout . <br /> Planning Considerations <br /> .. Improper use of straw bale barriers has been a major problem . Straw bale barriers have <br /> been used in streams and drainageways where high water velocities and volumes have <br /> destroyed or impaired their effectiveness . Improper placement and installation of the barriers , <br /> such as staking the bales directly to the ground with no soil seal or entrenchment, has allowed <br /> undercutting and end flow . This has resulted in additions instead of removal of sediment from <br /> runoff waters . Finally, inadequate maintenance lowers the effectiveness of these barriers . <br /> Aw Trapping efficiencies of carefully installed straw bale barriers on one project in Virginia <br /> dropped from 57 percent to 16 percent in one month due to lack of maintenance . <br /> There are serious questions about the continued use of straw bale barriers as they are <br /> presently installed and maintained. Averaging approximately $3 to $ 6 per linear foot installed <br /> ($ 10 to $ 20 / m ) the thousands of straw bale barriers used annually in Florida represent <br />.. sufficient expense that optimum installation procedures should be emphasized . If such <br /> procedures are carefully followed , straw bale barriers can be quite effective . <br /> 4- 14 <br />