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CITY Of EVERETT STORMWATER MANAGEMENT hfANUAL <br /> Typical Biofiltration Swale <br /> Data <br /> Drainage <br /> Systam Maintenance Activitlee anG Condltlons <br /> Frequency Feature ✓ � � � Problem Condidonc to Check For That Should Ewist <br /> M General Sediment Sediment deplh exceeds 2 Inches or inhibits Remova sediment deposds on grass <br /> Accumulation on vegetation growth in 10 percent or more o! treatrnent area of Ihe bioswale.When <br /> Grass swale. finished,swale should be level from side to <br /> sida and drain freeiy:oward outlet. <br /> There should be no amas ol standing waler <br /> once;nflow has ceased. <br /> M Generel S;anding Water When water stands m the swele between storms Any of the tollowing may apD�Y� remove <br /> and does not drein freely. sediment or frash blodceges, improve gratle <br /> from hend lo toot ol swale, remove clogged <br /> check dams, atld unAerdrems or convert lo a <br /> wel biofilNation swale. <br /> M General Flow spreader Flow spreader uneven or clogged sc Ihat fiows Level the spreader and clean so that fiows <br /> are not uniMrmly disVibuted through antire are 5praad evenly over enlire swele widlh. <br /> swale width. <br /> M General Constant Baseflow When smell quentlfies ai weter continually flow Add a iow-flow pea-grevel drein ihe lenglh of <br /> througb the swale,even when Ihe wea0�er has the swale or by-pass the basefiow around Ita <br /> been tlry loi weeks, antl an emtle0,muddy swale. <br /> channel has fo�med in the swale bottom. <br /> M General Poor Vegetation Whan grass is sparse or bare or emdetl palches Oetermine why grass growlh Is poor and <br /> Coverage occur m more than 10 percent ol the swale correct that�antli�ion. Re-plant with plugs of <br /> buttom. grass hom the upper slopa�. plant m the swale <br /> botlom at:.inch intervals.Or re-seed into <br /> loosened,fertde soil. <br /> M General Vegetation When the grass becomes ezcessively tall Mow vegelation or remove nuisance <br /> (greater than 10 inches);when nuisence weeds vegetelion so thal Pow not impeded. <br /> and oU�ar veAelation starts lo lake over. Grass should be mowed fo a height of 3 fo 4 <br /> inchas. Remove grase clippings. <br /> M General Excessive Shading Grass growth is 000r because sunlight does not If possible,trim back over-henging limbs and <br /> reach swale. remove brushy vegetetion on edjacenl <br /> slopes. <br /> Appen�lices <br /> , F-�',--• :. <br />