Rain Gardens, A Wise Way to Use Runoff - U of I Extension

News Release

Rain Gardens, A Wise Way to Use Runoff

This article was originally published on April 6, 2009 and expired on April 13, 2009. It is provided here for archival purposes and may contain dated information.

When we receive rain, a lot of it falls on surfaces that cannot soak up water. Roofs and driveways create large amounts of runoff—much of which ends up in storm drains. It is estimated that water from these areas can increase stream flow by up to five times! Sump pumps also pump a lot of water that must be drained. Instead of allowing all of this water to uselessly drain away, one can create a place that will allow the water to drain back into the ground, away from the house. In addition, by planting the site to native perennial plants, it can add an aesthetically pleasing landscape to the yard. This is the idea behind a rain garden.

According to U of I Extension Educator Duane Friend, a typical rain garden is an area that is 4 to 8 inches deep, with a flat bottom. The size of the garden will depend on soil type and the amount of surface runoff going into the garden, but for most yards it would need to be around 75 to 300 square feet in size. The shape will be influenced by such things as surrounding slope, and how it will retain water. A berm is built on the down slope end and sides to help keep water from running out of the garden. Rain gardens are designed to drain in an average of two days; so standing water, along with mosquito concerns, should not be a problem.

There are many native wildflowers that will work well in a rain garden setting. Native perennials do not need fertilizers and pesticides to thrive and, therefore, will not increase water quality problems. These plants have extensive root systems which will also take in large amounts of water as it percolates through the soil. It is usually best to start the garden with plugs instead of seeds.

Rural homes can also benefit from having a rain garden in the landscape. If designed properly, the garden can enhance the beauty of yards and neighborhoods, along with providing habitat for birds and butterflies.

For more information on rain gardens, visit the following websites:



Source: Duane Friend, Extension Educator, Energy and Environmental Stewardship, friend@illinois.edu

Pull date: April 13, 2009