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Rain Gardens Weed Out Pollutants

Thinking about doing a little landscaping? You might consider planting a “rain garden” that will brighten up your yard while reducing harmful pollution in your neighborhood and surrounding watershed.

Rain gardens are easy to build and can trap up to 99 percent of pollutants from urban storm runoff, according to a recent study in Environmental Science and Technology. By sending runoff back into the soil instead of letting it run down the street into sewers or waterways, rain gardens improve water quality and can also convert some pollutants into less harmful compounds, the two-year study by researchers at the University of Connecticut found.

On a typical city block today, more than half the rainwater that falls ends up as runoff containing metals, oils, and fertilizers. The researchers showed how rain gardens, which are little more than shallow depressions in the earth planted with hardy shrubs, could significantly reduce concentrations of nitrates, ammonias, phosphorous and other pollutants. In fact, rain gardens are a way of putting back what nature once provided and developers wiped out with paved surfaces: the earth’s natural drainage system.

Too much storm water runoff can cause flooding and human and aquatic health problems. Excess nutrients that make their way into rivers and bays cause algae blooms that make it difficult for shellfish and other aquatic life to survive. Bacteria from runoff may wash into swimming areas, creating health hazards for people who use them. Runoff also contains insecticides and pesticides that may cause hormonal disruptions in the offspring that live in affected waters.

If everyone planted a rain garden in their yard, they might also help save themselves some money: The less storm water that needs to be treated, the easier it is for treatment plants to keep costs down.

For more information on this study, and on how to build a rain garden, go to www.sciencedaily.com/releases/2006/01/060126193136.htm.

For information on storm water runoff, the problems it causes and how to prevent it, go to www.epa.gov/weatherchannel/stormwater.html. For information on nitrates and their potential endocrine-disrupting effects, click here.

To read more about this and other environmental health issues, go to www.healthandenvironment.org, www.environmentalhealthnews.org or www.ourstolenfuture.org.