Storm water runoff can be a big problem in summer during heavy thunderstorms. As the water rushes across roofs and driveways, it picks up oil and other pollutants. Municipal storm water treatment plants often can't handle the deluge of water, and in many locations the untreated water ends up in natural waterways. The EPA estimates as much as 70 percent of the pollution in our streams, rivers, and lakes is carried there by storm water.
To reduce the excess water runoff, many towns are encouraging businesses and homeowners to install rain gardens in their yards. Rain gardens are specially constructed gardens located in low areas of a yard where storm water can collect. The idea is to have the water naturally funnel to this garden. The rain garden collects water runoff and stores and filters it until it can be slowly absorbed by the soil.
The garden's size and location depends on the yard. The ideal situation would be to locate the garden in a natural depression. You also can funnel water from downspouts on gutters into the garden. The soil should be well drained so the water doesn't sit in the garden for more than two days. A special 'rain garden' soil mix of 50 to 60 percent sand, 20 to 30 percent topsoil, and 20 to 30 percent compost is recommended. You can dig this mixture into the soil to depth of 2 feet before planting.
The most difficult part of building a rain garden can be plant selection. Plants need to be tough enough to withstand periodic flooding, yet attractive enough to look good in the garden. Deep-rooted, low-care native plants, such as asters, and tough non-natives, such as daylilies, are best. If properly designed, the rain garden can consist of a blend of attractive shrubs, perennials, trees, and ground covers. Planting strips of grass around the garden and using mulch also can help filter the water.
For more information on creating a rain garden and for sample garden designs, go to: Rain Gardens of Western Michigan.
Article published on June 23, 2008.