Many municipalities and states are embracing the use of Green Infrastructure as a sustainable means of treating polluted runoff. The District supports the Cities of Roswell and Atlanta for taking the initiative to require Green Infrastructure on new development sites. Click Here for more information on Green Infrastructure from the Environmental Protection Agency's website.
Other forms of Green Infrastructure include green roofs, pervious pavement, bioswales, and harvesting rainwater in cisterns and reusing it for irrigation, flushing toilets, or supplying cooling towers.
Green Infrastructure is an alternative approach to managing stormwater runoff that emphasizes infiltration, evapotranspiration, and rainwater harvesting techniques. Urban stormwater runoff contains numerous pollutants that are often times dumped directly into our creeks and streams without any type of treatment.
Green Infrastructure is designed to prevent the 'first flush' (typically the first 1.0" of rain) from running off a site. One of the more common means of handling this polluted runoff is through a rain garden (or bioretention). Rain gardens are vegetated depressions that break down pollutants such as nitrogen, phosphorus, and hydrocarbons through microbial action and filtration. About half of the water exits the rain garden through evapotranspiration (combination of evaporation and transpiration) and the other half infiltrates into the underlying subsoils.