May 2008

Rain Gardens Reign

Kansas City sets an ambitious goal, and communities around the country follow.

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By Margaret Buranen

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UDPREP has the distinction of having had two national experts on rain gardens speak to its members within the same year. In March 2007, more than 100 members attended a presentation by Roger Bannerman of the Wisconsin Department of Natural Resources. The event was held at the Ryerson Woods Welcome Center in Lake County, where attendees could see several LID features: two rain gardens, bioswales, two cisterns (one above and one below ground), and permeable asphalt paving.

Inspired by this program, Steve McLevich, the Libertyville, IL, Parks & Recreation Department maintenance supervisor, got the idea for a project to improve the quality of water in Butler Lake, which is a high-quality (advance identification, or ADID) wetland. The Village of Libertyville applied for a Watershed Management Board grant for cost-share to install two rain gardens and a vegetated swale to handle runoff from a parking lot at the lake.

Photo: Sara Cohen, Massachusetts Department of Conservation and Recreation
Clustering these single-family homes on smaller lots allowed more of the site to be preserved as woods and open space.

For UDPREP’s annual meeting in September, the speaker was Commissioner Sam Adams of the Portland, OR, Bureau of Environmental Services. Adams spoke on street-side infiltration practices, showing scenes of successful retrofits in Portland, part of that city’s Green Streets program.

 “The combination of [the two] programs has spurred the interest of several of our municipalities, who are following up on designing rain gardens in their public works projects—streets especially,” says Werner. “UDPREP will be following up these events with a rain garden installation workshop.”

Portland’s Green Streets
Adams and Portland’s other stormwater officials deal with runoff from an average annual rainfall of 37 inches. Portland’s Green Streets program combines rain gardens with such LID features as permeable pavement, green roofs, curb extensions with plantings, and planters that let water infiltrate.

With these features, Portland can reduce peak stormwater flows by as much as 85%, stormwater volume by 60%, and pollution in runoff by up to 90%. But there’s still a lot of runoff and more impervious surfaces from new developments. Adams told the UDPREP members that Portland’s goals include 3,700 green streets; 250 acres of ecoroofs; and 250 acres of planters, swales, and rain gardens.

An impressive example of a Portland project with multiple LID features is the retrofit at the Mt. Tabor Middle School. This innovative joint project of the Portland Public Schools and the Department of Environmental Services manages runoff from a total area of about 2 acres. It includes a swale, six planters, three drywells, a curb extension adjacent to the school, and, of course, a rain garden. In 2007, the American Society of Landscape Architects gave a national award to the project’s rain garden, which replaced 4,000 square feet of asphalt.

“Rain gardens are a decentralizing strategy,” says Tom Evans, a landscape architect with URS Corp. in Cleveland, OH. That decentralization means that rain gardens, even those installed through community projects, become the homeowner’s responsibility to maintain. Requiring homeowners to attend workshops to learn about their rain gardens and other LID features, such as the programs profiled do, connects the homeowners to the programs long-term and convinces them that their efforts benefit everyone.

There’s also peer pressure to keep the gardens looking as well as their neighbors’ gardens do. Kari Mackenbach, a water resource specialist with URS in Columbus, OH, says that a follow-up study showed 95% of the Maplewood, MN, homeowners maintained their rain gardens. Maplewood has been installing rain gardens for years as part of an ongoing street reconstruction program. Mackenbach mentions one case where the neighbors were maintaining the rain garden for a homeowner who had stopped caring for it.

The varied projects described here show that rain gardens—by themselves or combined with other LID practices—can improve water quality by lessening stormwater runoff. Rain gardens are cost-effective, low-maintenance, and attractive. Projects such as these can also help satisfy the EPA’s National Pollutant Discharge Elimination System Phase II requirements for public involvement and education. Rain gardens are up to date, and not just in Kansas City.

Author's Bio: Margaret Buranen of Lexington, KY, writes on environmental and business topics for a number of national publications.

What Do You Think?

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WardWilson

August 5th, 2008 10:13 AM PT

tblixt makes an important point. There are some sites where a rain garden won't work. I see rain gardens as one of many tools we can use. When they are applicable, they provide many benefits, but we'll sometimes need a different approach (cisterns, planters, green roofs, end-of-pipe treatment, etc.). It's important to begin with an objective analysis of the problem and objectives, then pick your tool and go to work. I am the consultant project manager of the Mt. Airy Rain Catchers project mentioned in the article.

tblixt

July 2nd, 2008 9:38 AM PT

With cities requiring more density on infill projects, homes are being placed on postage stamp sized lots - there is no room for a yard, let alone a rain garden.

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