Laserfiche WebLink
C. BIOFILTRATION <br /> Bloflltratlon systems use vegetation and/or sand <br /> ..._ r, <br /> and other natural filtration media to reduce pollut- <br /> ants In stormwater runoff. Filtration, Infiltration,ad- °•� ,� Wet Tolerant Species sorption,sedimentation,and biological uptake of �.• <br /> stormwater pollutants are all methods utilized by <br /> = <br /> biofiltration systems. `- Wet Prairie Plantings <br /> Vegetated Swales- Vegetative swales possess <br /> less than six percent side slopes and are wide and <br /> shallow to maximize flow residence time and pro- ` ' °`� �,•, ^,} -�� , <br /> mote pollutant removal.They are often used down- <br /> stream from detention facilities,around parking lots, <br /> In parking lot medians,and along roadsides. Figure VI-4: Vegetated Shale <br /> Vegetated Filter Strips- Filter strips consist of <br /> vegetated sloped strips in which flow is distributed <br /> broadly along the length of the vegetated area <br /> as overland sheet flow.Requiring ample space to <br /> spread the flow over a wide area at a small depth, ,v, ', Wet Tolerant Species <br /> suitable areas for filter strips Include shoulders along <br /> uncurbed roads,areas between parking lots and L / Wet Prairie Plantings <br /> stormwater Inlets, adjacent to vegetated swales <br /> and upstream of Infiltration facilities. <br /> 6"-9" Ponding <br /> Media Filters- Media filters strain runoff through 2"-3" Mulch <br /> a medlum,such as sand,peat,compost, pellet- <br /> Ized leaf compost,Into an underdrain system that <br /> �� �, 4'-0" Planting Soil <br /> conveys treated runoff to a detention facility or ��� J.the point of ultimate discharge.They can be used —..—._.-..._.-_......,._.� = ' ^r— - Fllter <br />Fabric <br /> In highly developed sites or be retrofit to existing };r <br /> sites. iil _ Optional Sand Layer <br /> Catch Basin Filter Inserts- Catch basin filter ``.... — Gravel <br /> Inserts are suspended within catch basins and <br /> designed to strain sediment.Since they require high Figure VI-5:Bloretentlon Parking Medlon Drain <br /> maintenance to avoid hydraulic(allure,they are <br /> applicable only to a small drainage area. <br /> ps <br /> Hbdlrfofllhe Desian • - •rk�, <br /> Stormwater Dosign Guidelines <br />