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CITY OF EVERETT STORMWATER MANAGEMENT MANUAL <br /> i <br /> ' 4. Wherc the size of the drainage area is no greater than one-faurth ecre per l00 feet of bartier <br /> length;thc maximum slope length bchind the barrier is 100 fcet; and the maximum slope gradient <br /> bchind thc bartier is 2:1. <br /> 5. Where effcctiveness is required for less t6an 3 moaths. <br /> 6. Under no circumstances shall straw bale bartiers be wnstructed in streams,channels, swales or <br /> ditches. <br /> 7. Straw bale barriers should not be used where rock or hard surfaces prcvent the full and unifortn <br /> anchoring of the bartier. <br /> Design and Installation Specilications <br /> l. Bales shall be placed in a single row,lengthwise on the contour,with ends of adjacent bales <br /> tightly abutting one another. An over0ow/discharge point must be designated for cunoff <br /> intcrcepted by the straw bales. <br /> 2. All bales shell be either wire-bound or sning-tied. Straw bales shall be installed so that bindings <br /> are ariented around the sides rather thaa along the tops and bottoms of the bales in order to <br /> prcvent detcrioration of t5e bindings. <br /> 3. T6c baRier shall be entrenched and backf'illed. A trenc6 shill be excavated the width of a bale <br /> and the length of the proposed barrier to a minimum depth of 4 inches. The trench must bc deep <br /> enough to remove all gass and other material that might allow wderflow. After the bales are <br /> staked and chinked(filled by wedging),the excavatcd soil shall be backfilled against the barrier. <br /> Backfill soil shall confortn to the ground level on the downhill side and shall be built up to <br /> , 4 inches against the uphill side of the barrier. <br /> 4. Each bale s6a11 be securcly anchored by at least hvo stakes or reinforcement bazs driven through <br /> the bale, The first stake in each bale shall be driven toward the previously laid bale to force[he <br /> bales together. Stakes or rcinforccment bars shall be driveo deep enough into t6e ground to <br /> securely anchor the bales. Stakes should not extend above the bales but instead s6ould be driven <br /> in tlush with the top of the bale for saf?ry reasons. <br /> 5. The gaps between the bales shell be chinked(filled by wedging)with sRaw to provent water from <br /> escaping betwcen the bales. Loose straw scattercd over the area immediately uphill from a straw <br /> bale barticr tcnds to increase barrier efficicncy. Wedging must be done carcfully in order not to <br /> separate the bales. <br /> Malntenance Standards <br /> 1. Straw bale barticrs shall bc inspected immediately after each runoff-producing rainfall and at <br /> least daily during prolongcd rainfall. <br /> 2. Close attention shall be paid to thc repair oC damaged bales,cod cuns, and undcrcutting bencalh <br /> bales. <br /> 3. Necessary repairs to barriers or replacement of bales shall he accomplished promptly. <br /> 4. Sediment deposits should be removed after each runoff-producing rainfall. They must be <br /> removed tvhen the level of deposition rcaches approximatcly ono-half the hcight of the barticr. <br /> 5. Any sediment deposits remaining in pla�e after the straw bale bacner is no longer�equired shall <br /> bc dressed to conform to the existing grade,prepared and seeded. <br /> 6. Straw bales used ns a temporary straw b,�le barrier shall be removed afler project completion and <br /> stebilization to prevent sprouting of unwanted vegetation. <br /> Volume ll—Construction Stormwater Pollution Prevention <br /> 3-52 <br />