n. A garden that uses sandy soil to help filter stormwater runoff from nearby roofs, roads, and other hard surfaces.
2014
The Nine Mile Creek Watershed District is offering money to residents, schools, nonprofit groups, associations, businesses and others to pay for projects that protect and improve water and natural resources in the Nine Mile Creek Watershed District. … Eligible projects include raingardens, pervious pavers, cisterns, native habitat restoration and shoreline or streambank restoration projects, according to a news release.
2014
In Melbourne, Australia, a five-year scheme is establishing 10,000 "raingardens" — flower and vegetable beds underlain with sandy soil to help water filter away.
2001 (earliest)
Stormwater from the hospital and Lincoln Road will flow into a landscaped stormwater pond before flowing into Henderson Creek. Stormwater from the new car parks and some of the existing car parks will flow into swales and raingardens before entering Henderson Creek. All this is designed to cleanse the water from sediments and pollutants and to prevent flooding further downstream.
Rain Gardens are an alternative storm water management practice being applied as a pilot project at Somerset. The Gardens are a combination of grasses, shrubs, and trees that serve as ground cover, a middle story, and a canopy in simulation of a forest environment. The shallow, landscaped gardens manage stormwater through bioretention, combining physical, biological, and chemical processes to maximize pollutant removal. The settling of sediments in shallow pool areas, the natural processes of plants and microbes, and chemical reactions occurring in the soil allow the gardens to absorb and purify stormwater runoff.