Most parking lots may resemble a man-made wasteland even with cars sitting on top of them. But now they can serve a dual purpose by helping filter out pollutants in rainwater that might reach underground water sources.
The Environmental Protection Agency kicked off a study this week on how pavement materials can improve water filtration. A 43,000-square-foot section of a parking lot at the agency’s Edison, New Jersey facility serves as the test bed for three different types of permeable pavement. The agency also planted several rain gardens this summer to see how vegetation can aid in water filtration.
Storm water runoff can gather large amounts of debris, chemicals (antifreeze, motor oil) and other nasty sediment as it flows across impermeable parking lot and rooftop surfaces. Porous pavement could go a long way toward countering that–EPA employees will even contribute to the experiment during their daily commutes by representing traffic and adding vehicle-related pollution like leaking oil.
The filtered water won’t all go into the soil. Certain sections of the porous pavement test beds are lined with geotextile fabric to collect water samples. The impermeable fabric sections also have a perforated pipe to drain accumulated runoff into a dedicated collection tank.
So next time you’re watching dirty storm water run along gray pavement, just remember–the EPA’s Green Infrastructure Research Program has got your back.