Metro DetroitJuly 9, 2014
Rain gardens create a healthy landscape
By Linda Shepard
C & G Staff Writer
METRO DETROIT — A rain garden can beautify your yard, eliminate watering and keep stormwater contaminants away from rivers, lakes and streams.
“A swampy area is a key indicator as a great place for a rain garden,” said Nina Misuraca-Ignaczak, Clinton River Watershed Council watershed planner. “Rain gardens work with nature so you don’t have flooded areas that tend to be mosquito habitats and attract geese. Ideally, rooftop water runoff can be retained on site and, generally, you don’t have to irrigate your rain garden — it receives water naturally.”
Rain gardens also offer important ecological benefits.
“Rain gardens create a clean filtration system,” Misuraca-Ignaczak said. Plants and soils clean stormwater naturally, removing fertilizer nutrients and other pollutants as an attractive green solution to reduce water pollution and improve overall water quality.
According to Clinton River Watershed Council officials, stormwater becomes polluted when it washes over pavement and comes into contact with automotive fluids, sediment, trash, pet waste and more. Ordinarily, the runoff flows directly to rivers, lakes and streams. But by directing the runoff into a rain garden filled with native plants, the pollutants can be absorbed by the deep plant roots.
Oakland Township officials constructed a rain garden bioswale to keep pollutants from entering the lake and wetland areas at Lost Lake Park.
The garden is located between the two sections of the parking lot, said Ben VanderWeide, Oakland Township natural area stewardship manager. Native plants, including black-eyed Susan and native grasses — with roots that travel deep into the soil — catch the parking lot stormwater runoff and keep it out of Lost Lake.
“The native plant roots can handle the big fluctuations in the weather,” VanderWeide said. “The plants are able to stay green and sometimes go dry,”
Keeping nitrogen out of waterways is a significant function of a rain garden.
“Lake Erie and Saginaw Bay have high incidence of nutrients from fertilizers,” VanderWeide said. “The algae grow too much, die and decompose, using up oxygen. Then the fish die.”
Setting up a rain garden in your yard involves directing roof drain spouts toward the garden. The garden soil may need amendments, depending on its composition of clay or sand. The size of the garden will be related to the size of the roof drain area.
Rain gardens should be located at least 20 feet from any building. Design the garden as a “shallow bowl” to trap the first flush of storm water, say CRWC officials, who recommend a pond depth of 3-6 inches. If the site has clay soil, make the depression shallow to reduce the volume of trapped water. If the soil is sandy and porous, a deeper rain garden — possibly exceeding 12 inches in depth — could be considered.
Wet prairie wildflowers are excellent candidates for rain gardens, along with columbine, horsemint, spicebush, joe-pye weed, spiderwort and swamp milkweed. According to CRWC officials, native plants require less water and fertilizer than nonnative plant species, and many naturally are resistant to pests. When selected to fit site conditions, native plants create small ecosystems to attract birds, butterflies and beneficial insects.
For a complete list of native Michigan plants and more information about creating your own rain garden, visit crwc.org.