Photo credit: sunshinecity
No doubt about it, Americans like their cars—so it shouldn't come as a shock that a ton of space is being devoted to parking spaces, whether they're suburban driveways or sprawling lots around big retailers. But a recent study by Purdue University in Indiana indicates that this growing land-use trend plays a role in heating up urban areas and trapping water pollution.
The researchers surveyed the total area dedicated to parking in a midsize Midwestern county; they found that parking spaces outnumbered resident drivers 3-to-1 and resident families 11-to-1. The total parking area was larger than 1,000 football fields, covering more than two square miles."Even I was surprised by these numbers," says Bryan Pijanowski, the associate professor of forestry and natural resources who led the study in Purdue's home county of Tippecanoe. "I can't help but wonder: Do we need this much parking space?"
The results are cause for concern, says Pijanowski, in part because parking lots are a major source of water pollution, while presenting a host of other environmental and economic problems.
In Tippecanoe County alone, parking lots turn out about 1,000 pounds of heavy-metal runoff per year, says Purdue professor Bernard Engel, who used a computer model to estimate changes in water-borne runoff caused by land-use changes. Pollutants collect on the lots' non-absorbent surfaces and then are easily washed away by rain.
"The problem with parking lots is that they accumulate a lot of pollutants—oil, grease, heavy metals and sediment—that cannot be absorbed by the impervious surface," Engel says. "Rain then flushes these contaminants into rivers and lakes."
And we haven't even begun discussing the "urban heat island" effect that parking lots contribute to, which can raise temperatures by 2 to 3 degrees Celsius, according to Indiana state climatologist Dev Niyogi.
Tippecanoe County is part of nationwide trend, says Pijanowski, of Americans paving an increasing percentage of land each year for their cars and trucks. He says that businesses could get more creative about using combined-use or shared parking lots, which would save construction and property costs, while minimizing land use.
Or we could take a different approach to development planning and mitigate the monetary and environmental costs associated with parking areas in the first place, he says. "In many areas of the world, particularly Europe, cities were planned prior to automobiles, and many locations are typically within walking distance," Pijanowski says. "This is just one different way to plan that has certain advantages." ::Newswise