Picture the grime of city streets -- oil, grease and soot from cars and trucks; pet waste; trash and litter; sediment and debris from construction sites; and a mix of toxic chemicals. Now picture the same streets after a rainstorm. They look cleaner, right? Sure, but the debris and contaminants haven't just disappeared -- they've been swept through street drains and underground pipes then washed directly into the nearby river, lake or bay.

Wherever humans have paved or built over the natural world, dirty rainwater tends to run straight into our waterways, contaminating the water, destroying habitat and damaging property. Known as urban runoff, this type of pollution can have serious consequences, from fouling drinking water to closing beaches and poisoning shellfish beds. Indeed, the U.S. Environmental Protection Agency now considers urban runoff and pollution from other diffuse sources the greatest contaminant threat to our nation's waters. The good news is that there are a number of proven solutions that towns and cities can use to reduce runoff pollution.

One new and exciting approach has emerged in recent years. Called "low-impact development," it uses both simple common sense and technology -- strategically placed beds of native plants, rain barrels, "green roofs," porous surfaces for parking lots and roads, and other tools -- to help rainfall evaporate back into the atmosphere or soak into the ground, rather than polluting the nearest water body. In effect, low-impact development mimics nature's own filtering systems. The result is less water pollution from dirty runoff, less flooding, replenished groundwater supplies -- and often, more natural-looking, aesthetically pleasing cityscapes.

The pages that follow show how communities across America are cleaning up their water with low-impact development -- and both saving money and beautifying their environs as they do so.

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Based on STORMWATER STRATEGIES: Community Responses to Runoff Pollution, a May 1999 report by the Natural Resources Defense Council, reissued in October 2001 as a CD ROM with a new chapter on low-impact development.

Related NRDC Pages
Urban Stormwater Solutions
How to Clean Up Our Water

last revised 11.20.01