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CITY OF EVERETT STORMWATER MANAGEMENT MANUAL <br /> 3.3.15 BMP C234: Vegetated Strip � <br /> Purpose <br /> Vcgctated sfips reduce the transport of coarse sediment from a consWction site by providing a <br /> (emporary physical bartier to sediment and reducing thc runoff velocitics of ovedand tlow. <br /> Condifions of Use <br /> • Vegetated strips may be used downslope of all disturbcd areas. <br /> • Vegetamd strips are not intended to treat concentraied flows,nor arc they intended to treat <br /> substantial amounts of overiand flow. My concentrated flows must he conveyed through the <br /> drainr.ge system to a sediment pond. The only circumstancc in which averland flow can be <br /> treat�:�solely by a strip,rather than by a sediment pond,is whcn the following critena are met <br /> (see Table 3.11): <br /> Table 3.11 Vegetated Strips. <br /> ConMbuting Flowpath <br /> Averoga Slope Slope Pereant Length <br /> 1.5H:1V orless 67%orless 100feet <br /> 2H:1V orless 50%orless 115feet <br /> 4H:1 V or less 25°k or less 150 feet <br /> 6H:1 V or less 16.7%or less 200 Feel <br /> 10H:1V or less 10°/,or less 250 Feel <br /> Design and Installation 5pecifications <br /> 1. The vegetated ship shall consist of a continuous ship of dense vegetation with a pertncable <br /> top;oil and have a minimum 25-foot long flowpath. Grass-covcred,landscaped areas are <br /> generally not adequate because the volume of sediment ovenvhelms the grass. Ideally,vcgetated <br /> sttips shall consist of undisturbed native growth with a well-devcloped soil that allows for <br /> inLllrrtion of runoff. <br /> 2. The slope within the stria shall not cxcecd 4H:1 V. <br /> 3. The up6ill boundary of the vegetated strip shall be delineated with clearing limits. <br /> Maintenance Standards <br /> I. My arcas damaged by erosion or conshuction activity:tiall be secded immediately and protected <br /> by mulch. <br /> 2. lf morc than 5 feet of the original vegetated strip width has had vegetation rcmoved or is 6eing <br /> eroded,sod must be insta�led. <br /> 3. If therc are indications Ihat concentratzd flows are traveling across the bufCer,surface water <br /> conhols must he installcd to reducc the tlows cntenng thc buffcr,oT a��itional perimctcr <br /> protection must be iustalled. <br /> Volume II—Constructron StormwaferPollution Prevention <br /> 3-57 <br />