City tries to minimize asphalt effect

Sunday, September 23, 2007
Landscaping at the Kroger Fuel Center is an example of city parking lot regulations.

When driving to the store, whether it's a quick stop for a gallon of milk or for an extended stroll with a shopping cart, many motorists like to park conveniently close to the entrance.

A "sea of asphalt" in front of buildings, however, may create more environmental problems than the convenience it gives to consumers, and that is one reason for commercial parking regulations in the City of Greencastle.

The city tries to address such concerns by limiting parking spot locations and requiring landscape islands in large lots, City Planner Shannon Norman explained to the BannerGraphic.

A recent study by researchers at Purdue University points out a troubling nationwide trend in parking lots that increases urban heating and pollution.

Cars are a major source of water pollution, contributing 1,000 pounds of heavy metals into water runoff every year, according to study leader Bryan Pijanowski of Purdue.

"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," agreed study member Bernard Engel. "Rain then flushes these contaminants into rivers and lakes."

While Greencastle may not have many concentrated "seas of asphalt," city leaders are trying to lessen the negative environmental impact of paved parking lots.

"One way is to limit the amount of parking that is allowed in the front yard of a structure," Norman said. "Our current ordinances says that on all non industrial lots (including commercial), no more than 40 percent of the permitted spaces can be in the front yard if there are more than 50 spaces. The remainder of the parking must be in the side and rear yards."

That requirement specifically addresses the sea of asphalt issue, she said.

Another control is the placement of landscape islands in industrial lots that exceed 20 spaces for light industrial and 50 spaces for industrial.

"These islands must equal 5 percent of the area of the lot," Norman explained. "This is meant to specifically address excessive heat and emissions from large areas of hard surface. Also, the ordinance has standards for foundation plantings, groundcover materials and vehicle overhand -- all meant to aid in the reduction of environmental impacts because of parking."

One recent example of adding green spots to parking areas was the new fuel center added at the Greencastle Kroger.

Even though the fuel center was constructed on an existing site, the project did not have to come into full compliance with the city regulations because it was "grandfathered." However, the islands actually improved the fuel center project, Norman said.

Along with controlling traffic in the Kroger parking lot, the green spots are an attractive addition to the site.

Norman said she believes the city is making great strides in increasing the quality of storm water as well.

"Measures in place include standards for curbing, natural drainage and filtering, as well as the requirement of storm water quality maintenance by developers," she said.

Those efforts are visible in the construction project along Indianapolis Road and Washington Street where the new College Corner retail development is blossoming.

The Kroger Fuel Center and College Corner projects have both been required to install sediment control structures to catch and filter run-off from the parking lots.

Also, Gas America and the Kroger Fuel Center have both entered into agreements with the city for self-inspection of storm inlets and catch basins.

Purdue's study of parking looked at Tippecanoe County -- which has 355,000 parking spaces but is home to 155,000 residents.

Because parking lots also prevent the rain from soaking into the ground, they can worsen local flooding and erosion, Pijanowski said.

The paved surfaces also add to the urban heat island effect, which can raise temperatures by 2 to 3 degrees Celsius by absorbing more of the sun's rays than the surrounding ground, said Indiana state climatologist Dev Niyogi, a colleague of Pijanowski at Purdue who did not work directly on this study.

Norman said there is no data available on the ratio for parking spaces per person in Greencastle. But the public should be aware that the city has parking control measures in place to lessen the environmental impacts for the community.

Greencastle became an MS4 (Municipal Separate Storm Sewer) Community in 2005. There has been a concentrated effort to improve stormwater quality by requiring control measures for all new developments, she said. That includes a review of stormwater best management practices and soil erosion control plans for all new construction.

By understanding the parking space issue, Norman said, people can be aware of the importance of using alternate forms of transportation not only for their own personal health, but also the health of the environment.

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