Stormwater runoff from parking lots and driveways creates a host of environmental problems.  Pesticides and fertilizers, heavy metals from vehicle exhaust, motor oil, litter, sand and other debris that accumulates on road surfaces all end up in streams, rivers and bays, contaminating those precious resources and endangering wildlife and drinking water supplies.

Permeable paving is method of paving low-traffic roads, walkways and parking lots with materials which permit air and water to move through the surface, reducing surface runoff from stormwater and other sources. Permeable paving systems usually consist of a durable, porous concrete, asphalt or plastic load-bearing surface over a bed of crushed stone.

While many new permeable paving products are virtually indistinguishable from their traditional cousins, their impact on the environment can be a dramatic improvement.

Resources:

The EPA's Office of Water conducted some field tests of permeable paving systems for stormwater management. Their two-page report shows the results of various paving types.

A more detailed report from the New York Department of Environmental Conservation on Stormwater Management can be found on their web site. Buried deep inside their Design Manual, Chapter Nine (pages 9-37) is an excellent report on permeable paving with guidance for siting, installation techniques and costs.