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� qtr q :;�-.. � ' • .�'+Ya , •�s. <br />i., <br />;a <br />r; <br />Raingarden in a commercial development - Stillwater, MN <br />Design Criteria: <br />► Infiltration requires suitable soils. <br />► Minimum 10' setback and located clown <br />grade from home foundations. <br />► Best applied to drainage areas with relatively <br />flat slopes (5%). <br />Benefits: <br />► Can be very effective for removing fine <br />sediment, trace metals, nutrients, bacteria <br />and organics (Davis el al. 1998). <br />Provides many additional environmental <br />(habitat, improves air quality, urban micro - <br />climates), social ( creates a unique sense <br />of place ) and economic benefits ( reduces <br />development and maintenance cost, greater <br />lot yield, increases property vahjes). <br />► Well suited for high impervious areas. <br />► Reduces runoff volume. <br />► Flexible design, affording many opportunities <br />for creativity. <br />Limitations: <br />► Susceptible to clogging by sediment; <br />therefore maintenance and pretreatment is <br />necessary to maintain effectiveness. <br />► Not effective for large drainage areas (use <br />multiple structures, closer to source of <br />runoff). <br />► Space consumption (5%-10% of drainage <br />area). <br />Definition: <br />Bioretention is a terrestrial -based (up- <br />land as opposed to wetland), water <br />quality and water quantity control process. <br />Bioretention employs a simplistic, site <br />integrated design that provides opportunity <br />for runoff infiltration, filtration, storage and <br />water uptake by vegetation. <br />MANAGEMENT <br />SUITABILITY <br />Water Quality (V,,,o) <br />Channel Protection (V,i,) <br />'1 <br />Overbank Flood Protection (V <br />w <br />Extreme Flood Protection (v a,) <br />'fft] <br />Recharge Volume (VF,,) <br />Infiltration %vin appropnalc sc.L•; & Erle• co>uLl,rv,:; <br />Filtration <br />Temperature Control <br />x.., Settling <br />Evaporation <br />X Transpiration <br />X Soil Adsorption <br />X Biological/ Micro. Uptake <br />'�4 5 � Total Suspended Solids <br />�a Nutrients - Total Phosphorus/ <br />Tntal NitronPn <br />M-1 M Metals - Cadmium, Copper, lead, <br />and Zinc <br />s � a � Pathogens - Coliform, Streptococci, <br />1=. Coli 'less th-5=`I:!nrlenc sludcs <br />'_. Toxins - Chloride, Hydrocarbon, <br />- Pesticide`1':.is,t,:,:,:;u,de,;rad:Mns,urf�:-s <br />Note: Average pollutant removal expected when sizing based on MPCA <br />