Laserfiche WebLink
CITY OF EVERETT STORMWATER MANAGEMENT MANUAL <br /> } <br /> � 3. If erosion occurs 6ue to poorly controlled drainage, the problem shall be fixed and the croded <br /> area protected. <br /> 3.2.10 BMP C121: Plastic Covering <br /> Purpose <br /> Plastic covering provides immediate,shoR•tertn erosion protection to slopes and disturbed areas. <br /> Conditions of Use <br /> 1. Plastic covering may be used on dishubed arcas that requirc cover measures for less than 30 days, <br /> except as statr.d below. <br /> 2. Plastic is perticularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively <br /> rapid breakdown of most polycihylene sheeting makes it unsuitable for long-tecm(greater than <br /> 6 months)applications. <br /> 3. Cleaz plastic sheeting can be used over newly-seeded areas to crcate a greenhouse effect and <br /> encourage grass growth if the hydroseed was installed too late in the season to establish <br /> 75 percent grass covct,or if thc wct season started earlier than normal. Clear plastic should not <br /> be used tor this pucpose during the swnmer months because t6e tesulting high temperatures can <br /> kill t6e grass. <br /> 4. Due to tapid runoff caused by plastic s6eeting,this method shall not be used upslope of areas that <br /> might be adversely impacted by concentrated runoff. Such areas include steep and/or uustable <br /> siopes. <br /> ) 5. While plactic is inexpensive to purchase,the added cost of installation,maintenance,removal, <br /> � and disposal can make this an expensive material. <br /> 6. Whenever plastic is used ro protect slopes,water collection measures must be installed at the base <br /> of the stope. These measures include plastic-covered bertns, channels,and pipcs used to covey <br /> clean rainwater away from baze soil and dishubed azeas. At no time is clean runoff Gom a plastic <br /> covcred slopc to be mixed with dirty nu�off from a project. <br /> 7. Other uscs tor plastic include: <br /> a. Temporary ditch liner <br /> b. Pond liner io temporary scdiment pond <br /> c. Liner for bermed temporary fuel storage area if plastic is not rcaclive to the typc of fue! <br /> bcing stored <br /> d. Emergency slopc protection during heavy rains <br /> r,. Temporary drainpipe("elephant muJc") used to direct water. <br /> Design and InstaUation Specific4tions <br /> 1. Plastic sheeting shali ha��e a minimum thickncss of 0.06 millimcters. <br /> 2. lf erosion at the toe of a siopc is likely,a gravel bemi,riprap,or other suitable protcctio:;shall be <br /> installed at thc toe of the slope in ordcr to rcduce the velocity of runoff. <br /> 3. Plastic slope cover must be installed as follows: <br /> a. Run plastic up and down slope,not across slope <br /> b. Plastic may be installed perpendicular to a slope if tttc slopc Icngth is less than 10 tcet <br /> Volume!I—C�nstruction Stormwater Pollution Prevenfion <br /> 3-1B <br />