Simon Oxley/istockphoto
DCL
Every time it rains in the city, a great majority of that falling water lands on cement or asphalt. At first the rainwater puddles, then it begins to trickle out of parking lots and streets until its gushing down the storm drain in a rushing torrent.
When the water dribbles across the asphalt and cement, it picks up oils, metals, pesticides and other pollutants and carries it to down into the storm drain. All those impurities end up in the freshwater supply. This sounds like a huge problem.
It is a large problem, but it is one with a simple solution: Rain gardens. A rain garden is a shallow depression dug into the earth that is landscaped with sturdy shrubs and plants surrounded by bark mulch. The water from parking lots run into these depressions. The plants absorb 99% of the pollutants. And the bacteria in the soil keep harmful nitrates out of the water supply by converting them to nitrogen gas.
Rain gardens are effective all year round, and they aren?t too bad to look at. You can create a rain garden yourself.
Source: [url='http://www.sciencedaily.com/releases/2006/01/060126193136.htm']Science Daily
