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1 <br /> ' Design and Installation Specifications <br /> ' . Plastic slope cover must be installed as follows: <br /> 1. Run plastic up and down slope, not across slope. <br /> 2. Plastic may be installed perpendicular to a slope if the slope length is less <br /> than 10 feet. <br /> 3. Minimum of 8-inch overlap at seams. <br /> 4. On long or wide slopes, or slopes subject to wind, tape all seams. <br /> 5. Place plastic into a small (12-inch wide by 6-inch deep)slot trench at the top <br /> of the slope and backfill with soil to keep water from flowing underneath. <br /> 6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and <br /> ' tie them together with twine to hold them in place. <br /> 7. Inspect plastic for rips, tears, and open seams regularly and repair imme- <br /> diately. This prevents high velocity runoff from contacting bare soil which <br /> causes extreme erosion. <br /> 8. Sandbags may be lowered into place tied to ropes. However, all sandbags <br /> must be staked in place. <br /> ' . Plastic sheeting shall have a minimum thickness of 0.06 millimeters. <br /> . If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable pro- <br /> tection shall be installed at the toe of the slope in order to reduce the velocity of run- <br /> off. <br /> Maintenance Standards <br /> . Torn sheets must be p <br /> replaced and open seams repaired. <br /> P <br /> . Completely remove and replace the plastic if it begins to deteriorate due to ultra- <br /> violet radiation. <br /> ' . Completely remove plastic when no longer needed. <br /> . Dispose of old tires used to weight down plastic sheeting appropriately. <br /> Approved as Equivalent <br /> Ecology has approved products as able to meet the requirements of BMP C123: Plastic <br /> Covering. The products did not pass through the Technology Assessment Protocol — <br /> Ecology (TAPE) process. Local jurisdictions may choose not to accept this product <br /> approved as equivalent, or may require additional testing prior to consideration for local <br /> use. The products are available for review on Ecology's website at <br /> http:l/www.ecy.wa.gov/programs/wglstormwater/newtech/equivalent.html <br /> i <br /> 2014 Stormwater Management Manual for Western Washington <br /> ' Volume II- Chapter 4 -Page 295 <br />