Rain Gardens

Rain gardens are vegetated, shallow basins which hold rainwater that would otherwise flow rapidly into a stormwater system (see sidebar). This reduces the volume of water reaching the stormwater system and the stream which in turn helps prevent flash flooding. The soil and vegetation of rain gardens also act as a filter to remove some of the pollutants that would otherwise reach our streams.

Under normal circumstances, water will pool in a rain garden during and immediately following a storm, but the basin will be dry within a day or so. Many people express concern that a rain garden will encourage mosquitoes to breed, but a properly designed and maintained rain garden will dry before any mosquitoes emerge, killing any that may have been growing.

Rain gardens are frequently planted with native plants that are tolerant of wet conditions. Native plants with a course, deep root system are preferred to shallow-rooted plants like turf grass. As the roots of the native plants grow and then die off, the channels they leave behind allow water to infiltrate more efficiently. For this reason, a healthy rain garden planted with native vegetation will gradually become more efficient at absorbing water over the course of several years.

The rain garden here at Litzsinger Road Ecology Center is about a quarter of an acre in size. Located to the west of the North Prairie, our rain garden receives runoff from several neighboring properties as well as from our Savannah. Any water that flows out of our rain garden goes into the ephemeral pond, and overflow from the pond continues into the North Prairie. This rain garden was created in 2005 by excavating a few inches of soil in a series of small basins. These were lined with a layer of erosion matting and then planted with native seedlings and seed. It is now a well established habitat and has helped prevent soil erosion on the hillside and in the prairie.

Native Landscaping Manual from Shaw Nature Reserve (Chapter 2 focuses on Rain Gardens)

(http://shawnature.org/nativeland/NativeLandscapingManual/NativeLandscapingManual.aspx)

Native Plant Rain Gardens
(http://grownative.org/documents/GNRaingardenGuide.pdf)

River des Peres Watershed Coalition (http://www.riverdesperes.org)

10,000 Rain Gardens (http://www.rainkc.com/)