Whether you live in a city or along a lake or river, managing storm water run-off is something to consider in your landscape. Roof tops, roads, driveways and sidewalks create impervious surfaces. These surfaces cannot absorb water. If rainwater and snow melt is not able to be absorbed into the soil, run-off occurs. Run-off can carry sediments and pollutants such as oil, pet waste, debris and nutrients from lawn clippings and fertilizers. These pollutants can then end up in our rivers and lakes. Even municipal storm sewers may lead directly to rivers and lakes.
Simply put, a rain garden is a shallow depression filled with selected trees, shrubs, flowering plants and grasses designed to allow rainwater run-off to absorb into the soil. Rain gardens help to filter pollutants, absorb nutrients and allow sediments to settle before entering the ground water. Rain gardens are also useful in controlling erosion by trapping and allowing the water to infiltrate rather than run down a slope. Also, rain gardens may add interest and beauty to a landscape, or add elements to attract butterflies and birds.
While rain gardens are a popular trend right now, not all landscapes offer suitable sites. There needs to be enough room to allow water to be absorbed into the soil and not seep into a nearby building or basement. Also, if the soil is heavy clay or already saturated ponding may occur; and ponds have a different purpose in the landscape. Some situations can be amended to allow for proper infiltration. In these cases it is best to consult a specifically trained professional.
Dakota Soil Water & Conservation District offers Landscaping for Clean Water workshops in rain garden design and implementation. Site selection, size, shape, choosing proper plants and other materials, and maintenance are all topics covered in the workshops. Demonstration sites have been planted as part of previous workshops to show how attractive and beneficial rain gardens may be.