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Design and Installation Specifications <br />The vegetated strip shall consist of a continuous strip of dense vegetation with topsoil for a min- <br />imum of a 25-foot length along the flowpath. Grass -covered, landscaped areas are generally <br />not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips <br />shall consist of undisturbed native growth with a well -developed soil that allows for infiltration <br />of runoff. <br />- The slope within the vegetated strip shall not exceed 4H:1 V. <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 immediately and pro- <br />tected by mulch. <br />If more than 5 feet of the original vegetated strip width has had vegetation removed or is being <br />eroded, sod must be installed. <br />If there are indications that concentrated flows are traveling across the vegetated strip, storm - <br />water runoff controls must be installed to reduce the flows entering the vegetated strip, 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, compost, or other <br />material that is wrapped in netting made of natural plant fiber or similar encasing material. They <br />reduce the velocity and can spread the flow of rill and sheet runoff, and can capture and retain sed- <br />iment. <br />Conditions of Use <br />. Wattles shall consist of cylinders of plant material such as weed -free straw, coir, wood chips, <br />excelsior, or wood fiber or shavings encased within netting made of natural plant fibers <br />unaltered by synthetic materials. <br />- Use wattles: <br />o In disturbed areas that require immediate erosion protection. <br />o On exposed soils during the period of short construction delays, or over winter months. <br />o On slopes requiring stabilization until permanent vegetation can be established. <br />. The material used dictates the effectiveness period of the wattle. Generally, wattles are effect- <br />ive for one to two seasons. <br />2019 Stormwater Management Manual for Western Washington <br />Volume 11 - Chapter 3 - Page 377 <br />