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Maintenance Standards <br />. Repair any damage immediately. <br />Intercept and convey all evident concentrated flows uphill of the silt fence to a sediment trap- <br />ping BMP. <br />Check the uphill side of the silt fence for signs of the fence clogging and acting as a barrier to <br />flow and then causing channelization of flows parallel to the fence. If this occurs, replace the <br />fence and remove the trapped sediment. <br />Remove sediment deposits when the deposit reaches approximately one-third the height of <br />the silt fence, or install a second silt fence. <br />. Replace geotextile fabric that has deteriorated due to ultraviolet breakdown. <br />BMP C234: Vegetated Strip <br />Purpose <br />Vegetated strips reduce the transport of coarse sediment from a construction site by providing a <br />physical barrier to sediment and reducing the runoff velocities of overland flow. <br />Conditions of Use <br />. Vegetated strips may be used downslope of all disturbed areas. <br />Vegetated strips are not intended to treat concentrated flows, nor are they intended to treat <br />substantial amounts of overland flow. Any concentrated flows must be conveyed through the <br />drainage system to BMP C241: Sediment Pond (Temporary) or other sediment trapping <br />BMP. The only circumstance in which overland flow can be treated solely by a vegetated strip, <br />rather than by a sediment trapping BMP, is when the following criteria are met (see Table 1I- <br />3.12: Contributing Drainage Area for Vegetated Strips): <br />Table II-3.12: Contributing Drainage Area for Vegetated Strips <br />Average Contributing Area <br />Slope <br />Average Contributing Area Per- <br />cent Slope <br />Max Contributing area Flowpath <br />Length <br />1.5H : 1 V or flatter <br />67% or flatter <br />100 feet <br />2H : 1 V or flatter <br />50% or flatter <br />115 feet <br />4H : 1 V or flatter <br />25% or flatter <br />150 feet <br />6H : 1 V or flatter <br />16.7% or flatter <br />200 feet <br />1 OH : 1 V or flatter <br />10% or flatter <br />250 feet <br />2019 Stormwater Management Manual for Western Washington <br />Volume /I - Chapter 3 - Page 376 <br />