Why Lake Allatoona is full, Lanier isn’t

Every day, Lake Lanier’s water level is setting a new record low for that date.

Less than 60 miles to the west, Lake Allatoona has been full or nearly full all year.

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John Durso/AJC Special

In the cove near John Durso’s house, weed grow up to 6 feet tall where he used to fish.

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Both lakes are critical to metro Atlanta’s drinking water supply. Both are owned and operated by the U.S. Army Corps of Engineers. So why the difference?

In a word, size.

Lanier can hold more than five times as much water as Allatoona. And lately, the Allatoona basin has received more rain than Lanier’s.

It’s like the difference between using a garden hose to fill a whirlpool and a straw to fill a swimming pool.

This month, Lanier is losing more water through evaporation and withdrawals for drinking water than it receives, a net loss of about 11 million gallons per day.

Also, the corps has to release enough water from Lanier into the Chattahoochee River to meet the Atlanta region’s water needs — and to dilute its treated sewage discharges.

DRY COVER ON LANIER

John Durso used to catch striped bass off the dock behind his Lake Lanier home.

Now he feeds deer.

This is the second summer Durso has had a dry cove. In some spots, six-foot-tall reeds are growing where there used to be 12 feet of water. “The value of my house is just disappearing,” he said.

HOW ARE OTHER LAKES?

Lake Hartwell on the Savannah River, a federal reservoir between Georgia and South Carolina, is 14 feet below full and expected to keep falling through the fall.

West Point Lake on the Georgia-Alabama border is close to full, but is expected to start dropping rapidly as the corps releases more water to make up for the lack of rain.

Georgia Power’s lakes, including Lakes Burton, Oconee, Rabun and Seed, or at or near full.

WHAT’S NEXT?

If the drought continues to choke off rain, Lanier could set a record low level by the end of the year. By Sept. 12, the Corps expects Lanier to drop another foot and a half to an elevation of 1,052.3 feet above sea level. That’s lower than the December 1981 level that had been the record low until last December when the lake fell to 1,050.8 feet. If Tropical Storm Fay makes it as far as north Georgia, it would take four inches of steady rain to have any significant impact on Lake Lanier’s level.

Allatoona is expected to drop more than two feet by Sept. 12, but should not get close to its record low.

Sources: U.S. Army Corps of Engineers; the Southeast River Forecast Center