Published on 09/18/08

Urbanization causes concrete jungle to grow

By Stephanie Schupska
University of Georgia

Each day, more of Georgia gets covered in concrete. This development affects traffic and eats up agricultural land. Now, in North Georgia especially, it’s affecting the water system, says a University of Georgia expert.

“It’s the 800-pound gorilla in North Georgia,” said Liz Kramer, who works jointly with the departments of agriculture and applied economics and engineering in the UGA College of Agricultural and Environmental Sciences. “We really have to be thinking of that in issues of water quality and quantity. North Georgia is getting gobbled away by those housing density numbers.”

Between 2001 and 2005, approximately 13,410 acres of impervious surfaces were put down in Gwinnett County. The metro Atlanta area averaged 55 acres a day, the equivalent of about 41 football fields. Georgia in total covered 38 million acres.

When an area is covered in pavement, sidewalks, rooftops or buildings, rainwater can’t get into the ground. Instead, it rushes across the solid surfaces, picks up pollutants and washes into streams. This can cause an artificial spike in water levels, which quickly returns to the levels before the rain. Streams don’t stay as full as they did before housing growth.

“We’re no longer recharging our groundwater, and we’re reducing the amount of available water we can use to dilute the pollutants going into the streams,” Kramer said.

And it’s all because less and less water flows through the dirt, cleaning itself as it seeps through the ground and back into aquifers and streams.

Urban pollution sources

Ten years ago, streams in metro Atlanta had much more pesticides than those in agricultural areas, according to the U.S. Geological Survey. This was due to solid surfaces and improper pesticide use.

“Farmers understand pesticides and use them properly,” Kramer said. “If someone in an urban area is working on their two-acre lot and using pesticides, they’re going to go to a home-improvement store and pick up the first thing off the shelf. And we’re Americans. If a little is good, a lot is better.”

Farmers are often blamed for pollution, particularly North Georgia poultry farmers. But in urban areas, people pollution is a bigger problem.

“Tires produce a lot of zinc,” Kramer said. “Parking lots have a lot of heavy metals, a lot of oils, anything that drips out of your car.”

Changing landscape

The population boom in North Georgia has sent many farmers looking for cheaper land or out of the industry altogether. “As we develop, we’re pushing these guys out of the watershed,” Kramer said.

By raising chickens, poultry farmers also produce chicken litter, which contains nitrogen, phosphorus, potassium and other minerals important for crop growth. Farmers sometimes spread it for fertilizer. Near urban areas where less water is absorbed before it hits a stream, farmers have to be careful where they put chicken litter and how much they spread, she said.

“If someone’s applying chicken litter, even the same amount as they have in the past, any runoff would be magnified,” Kramer said.

Pollution is a problem, she said, but losing farmland and forests is a bigger problem because agricultural land helps maintain air and water quality and ecosystems, she said.

The challenge, she said, is to keep agriculture in North Georgia. “(It) provides so much value, and that value is not being accounted for because we just look at houses.”

Stephanie Schupska is the communications coordinator with the University of Georgia Honors College.