If you’d like to help improve storm water runoff at your own home, you’re in luck-building a raingarden is imminently do-able at a homeowner level.
For the layer of organic material beneath the shallow basin, combine equal parts compost (homemade or store-bought), sand (for porousness, to keep the water moving through the layer) and the soil that’s already on your property.
The second level could be anything from recycled concrete or rubble leftover from a demolition to a truckload of gravel.
Above the ground, go wild with plants and no one will be able to distinguish your raingarden from any other landscaping. Choose plants that can take occasional water inundation, since the basin will occasionally hold standing water.
Don’t worry about mosquitoes-a correctly built raingarden basin will only hold water for a few hours at a time before it disperses through the ground, and mosquitoes need several days’ worth of standing water to breed.
Include an overflow device to avoid flooding, but there’s no need to install a pipe that connects to the storm pipe below ground. At home, overflow water can go to the land rather than a pipe, but be sure that it drains away from your home.
Once the raingarden is installed, it requires no more maintenance than a conventional garden bed.
To get an idea of how it might look, visit the raingarden plot in front of the grounds department building, beside the Chicopee Complex. The office building is about the same size as the average house, and the raingarden there, which is no bigger than most home gardens, is built to handle drainage from both the parking lot and the front half of the roof. Another campus raingarden comparable to one built at home is the “Lumpkin Woods” area near Clark Howell Hall.