Pervious Concrete           

Pervious Concrete (sometimes referred to as
Permeable or Porous concrete) is a unique,
cement-based product that has a porous
structure allowing rainwater to pass directly
through the concrete into the soil.  It is also
referred to as "no fines" concrete because it
is manufactured by leaving out the sand or
"fine aggregate". Using Sufficient paste to coat
and bind the aggregate particles together
creates a system of highly permeable,
interconnected voids that drains quickly.
Water can pass through pervious concrete at
an incredible rate of 3-5 gallons per minute,
per square foot! 




                                                                              Image by Degussa Admixtures, Inc.

"Pervious concrete is a unique and effective means to address important environmental issues and support sustainable growth. By capturing rainwater and allowing it to seep into the ground, porous concrete is instrumental in recharging groundwater, reducing stormwater runoff, and meeting US Environmental Protection Agency (EPA) stormwater regulations. The use of pervious concrete is among the Best Management Practices BMPs) recommended by the EPA, and by other agencies and geotechnical engineers across the country, for the management of stormwater runoff on a regional and local basis. This pavement technology creates more efficient land use by eliminating the need for retention ponds, swales, and other stormwater management devices. In doing so, pervious concrete has the ability to lower overall project costs on a first-cost basis."
     - Wikipedia Enviromental entry