The vast parking lots common in the industry typically are made from impermeable asphalt. Every cloudburst causes stormwater to stream off this impermeable surface instead of soaking into the ground as the rainfall would in a natural setting. Water used in other external areas and loading areas also runs off the lot, increasing erosion of stream banks and causing flooding.
This runoff flows directly into steams or lakes or into municipal storm drain systems, not to a treatment plant. That’s a problem, because surface runoff is loaded with pollutants, ranging from toxic chemicals, debris, and motor oil to bacteria and other pathogens.
Because this runoff flows directly into streams or lakes, pollutant discharge is closely monitored under the Clean Water Act, whose goal is to restore U.S. waters to “fishable” and “swimmable” conditions.
The Environmental Protection Agency has the power to levy large fines to violators and doesn’t hesitate to use that power. Failing to manage surface runoff from a vast parking lot can cost big bucks.
Enter Auburn University asphalt engineers and the National Center for Asphalt Technology (NCAT), which researches asphalt technology for the transportation community worldwide.
One of the things NCAT is researching is “green” porous asphalt. That’s right—rainfall soaks through the asphalt into the ground, reducing runoff dramatically. Porous asphalt pavements not only promote infiltration, they improve water quality and recharge groundwater.
NCAT’s engineers would like to research just how effectively porous asphalt filters pathogens from the water that percolates through the asphalt’s filtering system, and how this can be accomplished without contaminating groundwater.
Porous pavements are not new, but recent advances have made it possible to modify the design and lower cost. NCAT has led the way in researching innovative asphalt mix designs, and they are seeking partners willing to be pilot sites for testing and sampling.