Bioretention is one way to capture and clean stormwater. Bioretention works by mimicking the natural environment and allowing runoff to infiltrate the ground. Bioretention cells, or raingardens, are landscaped shallow depressions that are designed to collect stormwater from rooftops, streets, sidewalks, and other hard surfaces that don’t allow water to soak in. They are constructed with special soil mixes that can absorb large amounts of water yet drain rapidly, treat pollutants in the runoff, and support plant growth. Typically these special soils are comprised of sandy soil and compost. Where class A EQ biosolids are available, they can make excellent additions to bioretention either as biosolids compost, or as a biosolids soil blend. Biosolids have the ability to hold large amounts of water yet improve soil drainage, chemically bind pollutants found in stormwater, and support healthy plant growth.
