Rain Gardens – Why Everybody Needs One

(This article originally appeared in the April 2010 issue of our monthly newsletter, The Leaflet)

April showers bring May flowers, but they also create storm water that quickly runs into streams and lakes, carrying with it pollutants and sediments that harm wildlife and human health.  A rain garden is simply a bowl shaped garden about 6″ deep that is positioned where it can catch stormwater and allow it to percolate into groundwater.  It is designed and constructed to drain within 24 hours to reduce standing water, and it is planted with species that can handle periods of inundation, but also dry soil conditions (see diagram below).  The best resource to learn more about Rain Gardens is The Vermont Rain Garden Manual, and we will also plan to have an installation demonstration some time this summer here at the farm.

The cousin to the Rain Garden is the Biofiltration planting – it’s a planting of wetland natives within a moving stream of water.  We installed a biofiltration bed on South Cove where a small ditch ran into Shelburne Bay (see photo above).  The idea is that the roots form a filter mat that collects fine sediments before exiting to the Lake.

Another technique for managing stormwater is called a “curb cut“, where a section of street curb is cut away at regular intervals so that water can run off into a rain garden instead of a storm drain.  The curb cut/rain garden combo is particularly effective at reducing the amount of pollutants that would normally enter lakes and oceans through street drains.

Burlington is a perfect example of an area that desperately needs all three solutions – it’s a populated area (high pollution potential) on a slope covered in impervious paved surfaces (think fast playground slide), perched above one of the largest lakes in the country, that also happens to serve as the drinking water source for 100+ towns.  So let’s filter it first – if there was a rain garden at every house, and curb cuts on every street, that directed stormwater into plantings that absorbed it before it could run into the lake, it would be like having thousands of Brita filters.  That would really be something huh?

Related articles

• What is a rain garden? (freshairlover.blogspot.com)
• Planning Your Garden: Why You Should Cultivate a Rain Garden This Year (apartmenttherapy.com)