"You can't put all your eggs in one basket, and we can't put all our straws in the same glass." Roy Fowler, general manager of the Cobb County-Marietta Water Authority
BY Clint Williams, The Atlanta Journal-Constitution Staff
ATLANTA, Ga., Sept. 4, 2000 — With precious little water falling from the heavens during Georgia's prolonged drought, more communities are looking in the opposite direction for a reliable source of water.
Because of increasing understanding of the rock formations beneath metro Atlanta --- and the daring that comes from desperation --- local communities are now pumping millions of gallons of water each day from ground generally thought to be solid, dry stone.
While surface water from reservoirs such as Lake Lanier and Lake Allatoona will remain the primary source of water for the region, experts say, wells will grow in importance along with the area's water demand.
"It takes a lot of bricks to build a wall, and groundwater is part of our program," says Roy Fowler, general manager of the Cobb County-Marietta Water Authority.
While Cobb began exploring for groundwater a decade ago --- and towns such as Lawrenceville and Fayetteville have pumped groundwater for years --- most public water utilities had ignored groundwater until pressured by the drought that's now dragging into its third year.
"Groundwater is definitely the most underutilized resource in North Georgia," said James Emery, a New Hampshire-based hydrogeologist who, in a 1996 study for the Atlanta Regional Commission, concluded that as much as 50 million gallons a day could be pumped from area wells. That's about 10 percent of the total daily water use in the ARC's 10-county region, enough water to meet the daily needs of about 625,000 people.
While there may be plenty of water beneath the ground around Atlanta, it isn't always easy to get at. The crystalline-rock Piedmont aquifer is mostly hard rock, making it much more difficult to find water.
South of the fall line, which runs roughly from Columbus to Macon to Augusta, the ground is much more porous, the water easier to find and the wells much more productive. Wells drilled in the Floridan aquifer system of southeast Georgia typically yield 1,000 to 5,000 gallons a minute.
"Metro Atlanta is basically sitting on the roots of Stone Mountain," said Glen Page, groundwater project manager for the Cobb water authority.
But those granite roots are splintered with cracks and crevices --- some 3 to 6 inches thick --- that often are pulsing with water. Finding those cracks is part science, part chance.
"You can drill two wells within 50 feet of each other: one dry, one producing 100 gallons a minute," said John Clarke, a hydrologist with the United States Geological Survey and co-author of several groundwater studies.
Two 600-foot-deep wells drilled in Cobb County in May yield a total of 32 gallons a minute, not enough for a public water system, said Page, although "it was in an area our geologists were excited about."
Drilling a well "is never going to be a sure thing, but you can boost the odds tremendously," said James Mayer, a hydrogeologist and assistant professor at the State University of West Georgia in Carrollton.
"In the past, wells were drilled in the most convenient location," said Mayer. "Now, with a more rigorous geological approach, the results are much better."
New techniques and new technology developed over the last decade or so have greatly increased understanding of what lies beneath the ground, geologists said. As a result, high-yield wells are being drilled with regularity.
Lawrenceville, which has used groundwater for more than 80 years, now gets an average of 500,000 gallons a day from two wells just south of City Lake. Three new wells will provide another 1.6 million gallons a day. Eventually, groundwater will nearly meet the city's peak summer demand of 2.8 million gallons a day.
Drilling a well is cheaper than building a dam, water managers said, and groundwater is generally much cheaper to treat.
"All you do is add chlorine and fluoride and send it on its way," said Rick Eastin, director of the Fayetteville water department.
By weaning itself from the Gwinnett County water system, Lawrenceville will save lots of money, said Juan Ruiz, a consulting engineering overseeing the groundwater project. The county charges the city $2.95 per 1,000 gallons. Groundwater will cost 17-20 cents per 1,000 gallons.
"It's free water, really," said Ruiz.
A Carroll County well drilled in December 1999 will provide 750,000 gallons a day --- nearly a quarter that system's total summer demand, at a cost of about 21 cents per 1,000 gallons.
"Groundwater is definitely the cheapest water you can develop --- if it is of high quality," said Jim Baxley, manager of the Carroll County Water Authority.
Well water high in minerals may need additional treatment.
Fayetteville has been pumping 750,000 gallons a day from two wells for nine years and has drilled two more wells that will provide another 432,000 gallons a day. The system uses about 2 million gallons a day overall.
In Stockbridge, three wells will provide a total of 500,000 gallons a day when they go online within the next week or so, said Stockbridge City Manager Ted Strickland. The system serves 3,000 customers, and the wells will meet about 70 percent of total demand.
The public wells differ from most of the residential wells that have gone dry this summer. Most of metro Atlanta's private wells that have failed are bored wells --- typically less than 100 feet deep that stop at bedrock. They collect water that trickles down through the soil from recent rains, and they are more vulnerable to drought. The drilled wells that area municipalities are sinking go deep into the bedrock, usually 200 to 400 feet, and draw water from a network of cracks in the rock.
While more smaller water systems have had success in meeting growing demand with well water, groundwater won't become the region's main water source, experts said.
"Groundwater is not the solution to metro Atlanta's water problems," said Clarke with the Geological Survey.
Groundwater, said Pat Stevens, chief of environmental planning at the Atlanta Regional Commission, "is never going to be a major source of supply for the region --- 5 percent tops."
But that's no reason to dismiss groundwater as a dependable supplemental source, water management experts said.
Cobb County, for example, gets about 1 million gallons a day from wells --- less than 1 percent of the system's capacity. Cobb County-Marietta Water Authority draws water from the Chattahoochee River and Lake Allatoona, but it continues to explore for groundwater and to drill wells with the long-range goal of pumping 5 million to 10 million gallons of well water a day.
"There is a tremendous amount of competition for allocations out of Lake Allatoona and Lake Lanier," said Fowler of the Cobb water authority, adding that alternative water supplies must be developed.
"You can't put all your eggs in one basket," Fowler said, "and we can't put all our straws in the same glass."
Copyright 2000 The Atlanta Journal-Constitution
