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BMP C123: Plastic Covering <br />Purpose Plastic covering provides immediate, short-term erosion protection to <br />slopes and disturbed areas. <br />Conditions of Plastic covering may be used on disturbed areas that require cover <br />Use measures for less than 30 days, except as stated below. <br />• Plastic is particularly useful for protecting cut and fill slopes and <br />stockpiles. Note: The relatively rapid breakdown of most polyethylene <br />sheeting makes it unsuitable for long-term (greater than six months) <br />applications. <br />• Due to rapid runoff caused by plastic covering, do not use this method <br />upslope of areas that might be adversely impacted by concentrated <br />runoff. Such areas include steep and/or unstable slopes. <br />• Plastic sheeting may result in increased runoff volumes and velocities, <br />requiring additional on -site measures to counteract the increases. <br />Creating a trough with wattles or other material can convey clean <br />water away from these areas. <br />• To prevent undercutting, trench and backfill rolled plastic covering <br />products. <br />• While plastic is inexpensive to purchase, the added cost of <br />installation, maintenance, removal, and disposal make this an <br />expensive material, up to $1.50-2.00 per square yard. <br />• Whenever plastic is used to protect slopes install water collection <br />measures at the base of the slope. These measures include plastic - <br />covered berms, channels, and pipes used to covey clean rainwater <br />away from bare soil and disturbed areas. Do not mix clean runoff from <br />a plastic covered slope with dirty runoff from a project. <br />• Other uses for plastic include: <br />1. <br />Temporary ditch liner. <br />2. <br />Pond liner in temporary sediment pond. <br />3. <br />Liner for bermed temporary fuel storage area if plastic is not <br />reactive to the type of fuel being stored. <br />4. <br />Emergency slope protection during heavy rains. <br />5. <br />Temporary drainpipe ("elephant trunk") used to direct water. <br />Design and • Plastic slope cover must be installed as follows: <br />Installation 1. <br />Specifications <br />Run plastic up and down slope, not across slope. <br />2. <br />Plastic may be installed perpendicular to a slope if the slope length <br />is less than 10 feet. <br />3. <br />Minimum of 8-inch overlap at seams. • <br />Volume II — Construction Stormwater Pollution Prevention - August 2012 <br />4-26 <br />