0831droughtaudState climatologist David Stooksbury explains why tropical storms alone can't pull Georgia out of the drought.
Rain from Tropical Storm Fay earlier this week pushed up the level of Lake Lanier by more than 2 feet, but the lake is still lower than it has ever been at this time of year.
"We're still in a drought," said Lisa Coghlan, spokeswoman for the U.S. Army Corps of Engineers, which operates Lanier. "One tropical (storm) is not enough to bring the lake back to normal."
When the storm began last Sunday, the lake stood at 1,053.31 feet above sea level. By Saturday, it had risen to 1,055.75. But that was still more than 15 feet below the normal full pool of 1,071.
What would it take to get the lake back to that level? Only the passage of time.
"We're going into September and October, historically a very dry period," said David Stooksbury, Georgia's state climatologist. "I don't think we can pull out (of the drought) until wintertime."
Stooksbury said even if we get multiple tropical storms, the effect is fleeting. "We just lose too much water to evaporation and plant use," he said.
Todd Hamill, hydrologist with the Southeast River Forecast Center in Atlanta, said summer heat and dense vegetation diminish the benefit of tropical storms, no matter how much it rains.
"Tropical storms are usually like a Band-Aid. They buy us more time until winter," he said. "Our real recharge period is December through March. That's when we don't have much evaporation and we don't have leaves on the trees."
Every Tuesday, the National Oceanic and Atmospheric Administration compiles a U.S. Drought Monitor report. For much of this summer, the corner of Northeast Georgia has been classified as "exceptional," the worst possible category.
As of Aug. 26, no county in Georgia was still in exceptional drought, but all of Northeast Georgia is still considered to be in "extreme" drought, the second-worst classification.
That may seem hard to believe, especially during a week when the ground became so saturated that many trees were uprooted in Tuesday's storms.
But when scientists try to quantify a drought, they're looking at the big picture. "These storms do have a significant impact to lawns, gardens and to local water systems," said Hamill.
But he said it takes a long time for that water to reach deep below the surface. One indication of the amount of groundwater is how long creeks and rivers stay full after the rain stops. "A lot of mountain streams rose quickly (during Tuesday's storms), but they also fell quickly, because a lot of their flow was taken up by groundwater," Hamill said.
This week's rain did refill most of the smaller reservoirs in Northeast Georgia. But local governments are playing it safe and are not assuming that their water resources are out of danger.
The third week of August, both Clarkesville and Cornelia enacted complete bans on outdoor watering, not even allowing the limited watering by hand that is still permitted under the state's Level 4 drought rules.
And despite the fact that some parts of Habersham County received more than 11 inches of rain this week, Clarkesville's ban is still in effect.
"The (Soque) river was pretty much at an all-time low and we had trouble with our pumping system," said Clarkesville Public Utilities director Tim Durham.
He said the city was having difficulty pulling water out of the Soque and pumping it into a storage reservoir. Clarkesville applied to the Georgia Environmental Protection Division for permission to impose a complete watering ban, which was still in effect as of Thursday.
Cornelia has a similar problem, according to city manager Donald Anderson. "Our main water source is Hazel Creek," he said. "And a week ago last Friday, it (the stream flow) just stopped. We were having to draw 3 million gallons a day from our reservoir instead of from the creek, and our reservoir dropped 5 feet."
After Tuesday's rain added about a foot of water to the reservoir, city officials decided they could relax the rules a bit. "We've lifted the mandatory ban but we're still asking people to voluntarily conserve," said Anderson. "We didn't lift the ban totally because we're still in a drought."
Fifty-five North Georgia counties, including Hall, are still under Level 4 drought rules. Residents are allowed to water on odd-even days depending on their street address, but they can only use a handheld garden hose and may not water for more than 25 minutes a day.
Kevin Chambers, spokesman for the EPD, said the agency has no plans to modify its drought policy despite Tropical Storm Fay or any potential hurricanes that may be brewing off the coast, such as Gustav.
Though the benefit from these storms is real, it doesn't last long. Lake Lanier rose 2 feet from Monday to Wednesday, but the increase slowed to only a few additional inches between Wednesday and Thursday.
Hamill said the only thing scientists can say with certainty is that the longer the drought continues, the more likely it is to end.
He said it is unusual for a drought in Georgia to last more than four years, and the current drought has already lasted three.
"Odds are that we will come out of the drought next year," Hamill said.