Rain Gardens

What is a rain garden?  Rain gardens capture and filter storm water runoff from impervious areas such as roofs, driveways, roads and lawns and allow it to seep slowly into the ground.  Plants, mulch and soil in rain gardens combine natural, phyisical, biological and chemical precesses to remove pollutants from storm water runoff that empties into our rivers and lakes.  Using native trees, shrubs and perennials enhance the beauty of yards and neighborhoods while providing natural habitat for birds, butterflies, hummingbirds and beneficial insects.

 The definition from Wikipedia:  

A 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). They can be designed for specific soils and climates.  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%.

Native plants are recommended for rain gardens because they generally don't require fertilizer and are more tolerant of one’s local climate, soil, and water conditions, and attract local wildlife such as native birds. The plants — a selection of wetland edge vegetation, such as wildflowers, sedges, rushes, ferns, shrubs and small trees — take up excess water flowing into the rain garden. Water filters through soil layers before entering the groundwater system. Root systems enhance infiltration, maintain or even augment soil permeability, provide moisture redistribution, and sustain diverse microbial populations involved in biofiltration.   Also, through the process of transpiration, rain garden plants return water vapor to the atmosphere.   A more wide-ranging definition covers all the possible elements that can be used to capture, channel, divert, and make the most of the natural rain and snow that falls on a property. The whole garden can become a rain garden, and all of the individual elements that we deal with in detail are either components of it, or are small-scale rain gardens in themselves.