Permeable parking lots could cut down on water contamination

Permeable parking lots being tested by researchers at North Carolina State University could cut down on water and soil contamination by allowing storm water to drain naturally through the soil rather than becoming runoff which could collect oil and other pollutants.

The permeable pavement system, developed originally during World War II for aeroplane runways and tank roads, is being tested for its suitability for modern city life. The pavement consists of layers of materials creating a surface which is not only permeable, but is also strong enough so support vehicles. A base layer of gravel is covered with a geotextile fabric for stability, followed by a layer of sand and a concrete or plastic lattice grid, though which is planted a spreading variety of grass to add further stability and texture.

Although the permeable system would initially cost a little more than conventional surfacing, the price may be repaid though lower pollution of surrounding waters, say the researchers. “The total cost could be less because permeable pavement may reduce the amount of money put into infrastructure such as ponds and storm drains,” said William F Hunt III, an urban storm water extension specialist in the Department of Biological and Agricultural Engineering at the university.

So far, says the research team, results are proving positive.

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