Numerous Pollutants Plague Parking Lots

Resource, Nov 2007

From suburban driveways to sprawling lots, Americans devote lots of space to parking spaces - a growing landuse trend that plays a role in heating up urban areas and adding to water pollution, according to a recent study.

Researchers from Purdue University surveyed the total area devoted to parking in the University's home county of Tippecanoe. They found that parking spaces outnumbered resident drivers 3-to-1 and outnumbered resident families 11 -to-1.

Bryan Pijanowski, associate professor of forestry and natural resources who led the study, says the results are cause for concern because parking lots present environmental and economic problems. They are, for instance, a major source of water pollution, he says.

ASABE member and Purdue professor Bernard Engel used a computer model to estimate changes in water-borne runoff caused by land-use changes. Engel, head of the Department of Agricultural and Biological Engineering, says parking lots are troublesome because they accumulate a lot of pollutants - oil, grease, heavy metals, and sediment - that cannot be absorbed by the impervious surface and then are easily carried away by rain.

The county's parking lots also produced 1,000 times the amount of heavy metal runoff and 25 times the total runoff that the same area of agricultural land would produce, Engel says.

The computer model, a type of "long-term impact assessment model," calculated predicted changes in runoff and compared them with runoff levels from land in agricultural production.

"People can help by first realizing that our land is not unlimited and that we need to use it prudently," Pijanowski says.

For more information, contact Pijanowski, bpijanow@purdue.edu or Engel, engelb@purdue.edu.