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Design and Installation Specifications <br />. The vegetated strip shall consist of a minimum of a 25-foot flowpath length con- <br />tinuous strip of dense vegetation with topsoil. Grass -covered, landscaped areas <br />are generally not adequate because the volume of sediment overwhelms the <br />grass. Ideally, vegetated strips shall consist of undisturbed native growth with a <br />9 Y 9 <br />well -developed soil that allows for infiltration of runoff. <br />. The slope within the strip shall not exceed 4H:1V. <br />. The uphill boundary of the vegetated strip shall be delineated with clearing limits. <br />Maintenance Standards <br />• Any areas damaged by erosion or construction activity shall be seeded imme- <br />diately and protected by mulch. <br />• If more than 5 feet of the original vegetated strip width has had vegetation removed <br />or is being eroded, sod must be installed. <br />. If there are indications that concentrated flows are traveling across the buffer, sur- <br />face water controls must be installed to reduce the flows entering the buffer, or addi- <br />tional perimeter protection must be installed. <br />BMP C235: Wattles <br />Purpose <br />Wattles are temporary erosion and sediment control barriers consisting of straw, com- <br />post, or other material that is wrapped in biodegradable tubular plastic or similar encas- <br />ing material. They reduce the velocity and can spread the flow of rill and sheet runoff, <br />and can capture and retain sediment. Wattles are typically 8 to 10 inches in diameter <br />and 25 to 30 feet in length. Wattles are placed in shallow trenches and staked along the <br />contour of disturbed or newly constructed slopes. See Figure II-4.2.14 Wattles (p.378) for <br />typical construction details. WSDOT Standard Plan 1-30.30-00 also provides information <br />on Wattles (http://www.wsdot.wa.gov/Design/Standards/Plans.htm#Sectionl) <br />Conditions of Use <br />• Use wattles: <br />• In disturbed areas that require immediate erosion protection. <br />• On exposed soils during the period of short construction delays, or over <br />winter months. <br />• On slopes requiring stabilization until permanent vegetation can be estab- <br />lished. <br />1 <br />2014 Stormwater Management Manual for Western Washington <br />Volume 11 - Chapter 4 - Page 376 <br />