What is a Stormwater Garden?

There are several names for a stormwater garden: rain garden, bioretention swale, vegetated swale, and others; all names will be used interchangeably throughout this article. They refer to gardens created to soak up rain water from surfaces that cannot soak it up: roofs, driveways, parking lots, sidewalks. Stormwater gardens are planted with wild flowers and other native vegetation and generally replace conventional lawns, grassy swales, or storm drains.

A rain garden has many environmental benefits. It absorbs more water than a lawn will, slowing down the rush of rain water. The plants in the garden capture silt and gravel that can be transported by rain and snow melt. They also improve water quality by helping to remove pollutants like nitrates, phosphates, or petroleum pollutants, and cool the rain water down after it has been heated up by the pavement. This cooling is critical as heated stormwater can impact wildlife that lives in streams and lakes.

Rain gardens are beautiful. They are landscaped with native plants that do well in the type of environment that they've been planted and so need little upkeep with watering and require no fertilizing. They provide habitat for wildlife, such as birds, insects, and other living things. They improve air quality by removing carbon dioxide (a greenhouse gas) and other air pollutants, and add oxygen to the air.

A rain garden should only be mowed down once or twice each year and replaces a section of lawn that may have previously needed regular mowing; thus they decrease noise and air pollution due to mowing and save energy.