By STACY SHELTON
The Atlanta Journal-Constitution
Published on: 05/01/07
Metro Atlanta is adding 55 acres worth of concrete, asphalt and rooftops every day — double the amount of new pavement since the last time it was measured in 2001, according to a new study out of the University of Georgia.
The study also showed the region continues to lose about 50 acres of trees a day — about four acres less than 2001.On one hand, the numbers tell the story of metro Atlanta's continuing prosperity. On the other, they show us what we're losing. With every new parking lot, shopping center and subdivision, piney woods and small creeks are disappearing, leaving even fewer natural places where the loudest noise is a bird call.
"It's scary stuff to look at this," said Liz Kramer, director of UGA's Natural Resources Spatial Analysis Laboratory and the study leader. "What we're seeing is not good planning and its cumulative effects."Kramer used detailed aerial photography to assess Georgia's tree canopy and hard surfaces. The Georgia Forestry Commission was the main sponsor of the study, which cost about $150,000. The state Environmental Protection Division also provided some funding.
For numbers on new hard surfaces and loss of tree cover, UGA focused on the 16-county metro area during the years 2001 through 2005. This is the second study of its kind from Kramer, which the forestry commission hopes will be used by planners to consider the regional impacts of development.
Gwinnett County, where an average of nine acres of pavement is laid down every day, has struggled to manage problems caused by rapid growth in recent years. Last year, the county became one of the first to start charging home and business owners a stormwater utility fee to manage the runoff from new paving and development.
More hard surfaces means fewer forests, wetlands and soils are available to soak up the water and more flooding. The same phenomenon exacerbates droughts. When hardtop blocks the rain from soaking in and refilling groundwater supplies, water isn't available to slowly drain into rivers and streams during a drought.
Many of the region's rivers and streams, and its two largest lakes — Lake Lanier and Lake Allatoona — are polluted from stormwater runoff, the rain that hits pavement, picks up dirt and grease, and drains into the nearest waterway. Scientists who study water quality say streams start to degrade when as little as 9 or 10 percent of a drainage area is covered with hard surfaces. Metro Atlanta's most populated counties — Cobb, DeKalb, Gwinnett and Fulton — are at least 18 percent covered.
Of all the counties, Clayton has the most hard surfaces at 25 percent — a number influenced by its small size and the presence of Hartsfield-Jackson International Airport and surrounding development. Jim Stokes, president of the Georgia Conservancy, the state's largest environmental advocacy group, said the numbers in the study "heighten the importance of our parks. That's why [Atlanta's] Piedmont Park becomes more important, and even more, smaller urban parks and green spaces."
The numbers help explain perennial environmental problems in the region as well: air and water pollution. Low-level ozone, a major component of smog, is created when car and industrial pollution cooks together on hot summery days. Roads, parking lots and other hard surfaces create a heat island effect, increasing the temperatures that worsen the region's smog.
With fewer trees, there's less shade available to cool temperatures, and fewer to filter some of the pollution that causes smog. The human cost is paid in asthma attacks, emphysema flare-ups and other respiratory illnesses caused by breathing unhealthy air.
"I think the moral of the story is that this was done without a regional plan," Kramer said. "This is a result of 5 million independent decisions. . . We can use this information to do a better job of planning to catch up and get ahead."Susan Reisch, the forestry commission's urban and community forestry coordinator, said she hopes communities will use the information, which includes statewide figures, as a benchmark to improve on.
"I think they [community leaders] get it when they see the visual images and data," Reisch said. Developers are getting it too. Conservation subdivisions, in which the developers leave as much as 40 percent of green space in return for higher density on the rest of the land, are slowly catching on. But it's still a hard sell in neighborhoods used to lot sizes of a half acre or more.
Michael Paris, president and CEO of the Council for Quality Growth, a metro Atlanta organization that represents the growth industry, said "local communities don't like the idea that the lots are smaller and politically, it becomes tough sometimes."