Illustrated Architecture Dictionary
rain garden is a planted depression that allows rainwater runoff from
impervious urban areas like roofs, driveways, walkways, parking lots,
and compacted lawn areas the opportunity to be absorbed.
This reduces rain runoff by allowing stormwater to soak into the ground (as opposed to flowing into storm drains and surface waters which causes erosion, water pollution, flooding, and diminished groundwater).
The purpose of a rain garden is to improve water quality in nearby bodies of water. Rain gardens can cut down on the amount of pollution reaching creeks and streams by up to 30%.
|A swale is a low tract of land, especially one that is moist or
marshy. The term can refer to a natural landscape feature or a
human-created one. Artificial swales are often designed to manage water
runoff, filter pollutants, and increase rainwater infiltration.
Bioswales are landscape elements designed to remove silt and pollution from surface runoff water. They consist of a swaled drainage course with gently sloped sides (less than six percent) and filled with vegetation, compost and/or riprap.
Save Our Waterways: Plant a Rain Garden
By Eliabeth Licata and Donna Evans-Deyermon
Excess storm water is the reason many of our Lake Erie beaches are closed during the summer on beautiful days. After washing over lawns, driveways, and parking lots, storm water runoff can carry with it chemical fertilizers, motor oil residues, even bacteria from pet and wildlife waste, all of which then runs into drains that often lead directly to waterways. From there, these contaminants can end up in drinking water reservoirs or favorite swimming spots.
Rain barrels (photo) are one way to save and use rain water before it becomes contaminated, but an even better way is to send the water directly into the earth, where water not used by plants soaks into lower soils, becoming naturally filtered before it eventually enriches wetlands and waterways.
Examples from Buffalo landscape architecture: