Pervious Concrete is a fantastic environmentally green choice for those who want a less expensive and environmentally friendly option to manage storm water. This porous concrete mixture has little to no sand which creates an open-cell structure that allows rain water to filter through to the underlying soil! According to the United States Environmental Protection Agency (EPA), storm water runoff can send as much as 90% of the pollutants (such as oil and other hydrocarbon liquids commonly found on parking lot and driveway surfaces) directly into our rivers and streams. The Pervious Concrete filters the water giving enough time for the pollutants to break down before they meet our streams and rivers. The use of Pervious Concrete can reduce the need for large detention ponds, skimmers, pumps, drainage pipes and other storm water management systems. Expensive irrigation systems can be downsized or even eliminated. Pervious Concrete is a durable material; parking areas properly designed and constructed will last 20-40 years with minimal maintenance. Thus, concrete, conventional or Pervious, is widely recognized as the lowest life cycle cost option available for paving.
Here is a great article on Pervious and Green Concrete http://www.forconstructionpros.com/publication/article.jsp?pubId=7&id=8798&pageNum=1
When it rains it drains!