Traditional asphalt driveways result in surges of rainwater runoff, especially during storms, that can overwhelm sewers and contribute to flooding. As all that water flows over the pavement, it can pick up oil, gas residue, fertilizers, pesticides, decing salt and other contaminants, which end up hurting water quality down stream.
A greener option that continues to gain acceptance and popularity is pervious pavement (also called permeable or porous pavement), which was first discovered around 1970. According to the Portland Cement Association (PCA), this material can absorb three to eight gallons of rainwater per minute, per square foot. This helps recharge local groundwater, reduces the need for retention ponds, and cuts down on flooding.
Homeowners even get extra points for pervious pavement toward qualifying for LEED certification from the U.S. Green Building Council. The EPA lists pervious pavement among its recommended Best Management Practices.
How does it work? Unlike conventional concrete, pervious concrete contains little or no sand, which normally fills in the tiny spaces between larger concrete components (stone, gravel, cement).
Although pervious pavement costs more to buy up front, it can save money in the long haul because it lasts longer than traditional concrete and requires less work to maintain.
The material has been successfully used in a wide range of paving applications, from streets to driveways, sidewalks, golf cart paths, retaining walls and French drains. All interstate highways in Georgia and Oregon are now repaved with porous asphalt.
For a list of manufacturers of pervious pavement, look here.
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