Dee Breeding from WILL-AM 580 narrates this week's installment.
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In a vegetable garden, you grow vegetables. In a flower garden, you grow flowers. In a rain garden you grow . . . . Well, unlike these others, the purpose of a rain garden isn’t limited to what grows in it. A rain garden is actually a landscape feature that functions as a small-scale, temporary wetland.
A rain garden typically consists of a shallow depression that is planted with shrubs, flowers, and grasses that are native to the region where it is located. A rain garden may be designed to receive water from a downspout or sump pump, or it may be located to intercept water that runs off of a parking lot or other impermeable surface.
Like a natural wetland, a rain garden provides important ecological services. Chief among these, it reduces the amount of water that enters streams via storm drains during and immediately following rain showers. In this way, a rain garden helps to alleviate flooding and cuts down on the amount of silt and pollution that washes into our waterways. Water that is held back in a rain garden infiltrates the soil more effectively than water that runs over a lawn, and thus it can also help to recharge groundwater locally.
Also like a natural wetland, a well-designed rain garden is a pleasure to look at, and it provides a bit of wildlife habitat, albeit on a small scale. During the growing season, native flowers used in a rain garden can attract butterflies and other beneficial insects. Over the winter, the seeds from those flowers and the berries from shrubs can provide food to attract birds.
It’s important to note that while a rain garden functions like a wetland, it is not a pond. A rain garden should dry up following precipitation, as the water it holds filters into the soil.
If you would like to see a really super rain garden that was completed last Fall, check out the project on the U of I campus just south of Allen Hall on Dorner Drive. There, students who were enrolled in a Natural Resources and Environmental Sciences internship class actually constructed a rain garden, based on a design that was produced by students from a previous class.
On Thursday, April 19, a ribbon-cutting ceremony will be held to celebrate the completion of the Dorner Drive rain garden. Students, faculty and staff who contributed to the project will be on hand, along with UI Provost Linda Katehi, Facitlities and Services Executive Director Jack Dempsey, and other campus administrators who supported the effort.
Beyond retaining and purifying stormwater, the Dorner Drive rain garden is intended to alleviate ponding around a substantial red oak tree on the site, and to prevent flooding on heavily used adjacent sidewalks. Construction of the rain garden was funded by U of I Facilities & Services in conjunction with the U of I Environmental Council, as part of a broader effort to develop and showcase sustainable practices on campus.
If you are intrigued by the possibility of creating your own rain garden, you may want to start with some of the links at the Environmental Almanac website. These include a how-to column by U of I Extension educator Sandy Mason, and a more detailed online manual for homeowners.
Both at home and in larger landscapes, rain gardens are an elegant, economical way to reduce the negative impacts of storm runoff.