Pervious Concrete Helps Control Storm Water Runoff
Used by developers in Florida and other Southeastern states since the 1970s to control runoff, erosion and flooding, pervious concrete attracted a good deal of attention at last month’s NAHB Green Building Show among attendees looking for solutions to address environmental regulations for more stringent storm water management practices. “It’s a great system in that it provides both day-to-day mitigation as well as catastrophic containment,” says Andy Young, technical representative of the California Nevada Cement Promotion Council and a specialist in storm water management. “With the change in EPA storm water runoff regulations, pervious concrete has really come into play because of its use in controlling pollution.” Like conventional concrete, pervious concrete is made from a mixture of cement, coarse aggregates and water. However, it contains little or no sand, resulting in a porous, open-cell structure through which water can pass readily, at a rate of three to five gallons per minute per square foot of surface area. Pervious concrete pavement provides a number of environmental advantages: - It reduces the amount of untreated runoff discharging into storm sewers.
- It directly recharges groundwater to maintain aquifer levels.
- More water is channeled to tree roots and landscaping, so there is less need for irrigation.
- Pollutants that can contaminate watersheds and harm sensitive ecosystems are mitigated.
- The hydrocarbon pollution coming from asphalt pavements and sealers is eliminated.
Pervious concrete has been embraced on the West Coast for its environmental benefits.
A storm water management system using pervious concrete can be highly effective in reducing total runoff and increasing the amount of filtered groundwater, according to Glacier Northwest, the largest concrete supplier in the Pacific Northwest, a region whose annual precipitation comes mostly from rainfall events of less than an inch. Pervious concrete pavement is being used for parking lots, subdivision streets, sidewalks and golf cart paths; and many home owners are using it to eliminate puddling, prevent erosion and save the expense of tying into local storm sewer systems. Typical applications include driveways, walkways, pool decks and patios. “Pervious Concrete Pavements” by the Portland Cement Association and the National Ready Mixed Concrete Association provides further information on the product. Following are links to information on projects around the country that have used pervious concrete to control water runoff, protect sensitive fish habitats and irrigate land: - To solve pollution runoff problems, city officials in Cerritos, Calif., paved a 10-acre overflow parking lot for a huge auto mall with 90,000 square feet of pervious concrete. This is the second largest pervious installation in the country and the second lot in the state to use pervious concrete paving. Click here.
- The Washington State Aggregates and Concrete Association has investigated the use of pervious pavements to manage storm water and protect salmon habitat. Click here.
- The California Nevada Cement Promotion Council has compiled a list of pervious concrete paving projects. Click here.
- Sustainable landscaping activists Owen Dell and Melanie Yanke of Santa Barbara, Calif., installed a pervious concrete driveway to prevent water runoff. Click here.
- Finley Stadium in Chattanooga, Tenn., installed pervious concrete in the parking area to collect storm water runoff and use it to irrigate the playing field. Click here.
- The City of Santa Monica is installing pervious concrete gutters on several streets to prevent polluted runoff, which eventually makes its way into Santa Monica Bay. Click here.
- Oregon Zoo’s Eagle Canyon exhibit used pervious concrete walkways to eliminate the need to install an extensive and potentially expensive drainage system. Click here.
For questions and answers on pervious concrete, click here.
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