A trio of Southern governors are fighting a water war to determine who has rights to the resources in Georgia's Lake Lanier, a man-made reservoir that provides drinking water to the nearly 4 million residents of the metro Atlanta area — and the city's getting thirsty.

Atlanta's population growth may have slowed with the economy, but its water use and a lingering drought have intensified legal battles that have been raging for the past two decades between Florida, Alabama and Georgia.

At issue is who controls the water in Lake Lanier — Congress or the U.S. Army Corps of Engineers.

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The 38,000-acre reservoir in north Georgia sups the state's capital but feeds the Chattahoochee River, which flows into river systems in Florida and Alabama. Those rivers in turn support wildlife farther downstream, including mussels and sturgeon, and provide water for power plants and other industries.

Lanier has faced terrible water shortages, a privation that Florida and Alabama blame on Atlanta's thirst, but Georgia's governor has defended the state's use of resources.

"We have treated this resource very responsibly from a consumption standpoint, from a conservation standpoint, from a utilization standpoint," said Republican Gov. Sonny Perdue.

Georgia has been trying to limit the amount of water it sends downstream to Florida to combat a record-setting drought, but was rebuffed in January by the U.S. Supreme Court, which let stand a lower court ruling that the state must consult Congress before changing any of the details of its water-sharing plan.

The waters of the Chattahoochee flow directly from the Lake Lanier's Buford Dam, which is managed by the Army Corps of Engineers. The Corps, itself an interested party, argued separately to the Supreme Court that it has authority over providing drinking water to Atlanta.

The dispute has rankled leaders in all three states, and the Republican governors of Florida and Alabama insist Georgia already uses too much water and needs to conserve more.

"This is about people that are going to be laid off," said Alabama Gov. Bob Riley in a 2007 interview. "This is about protecting jobs. This is about sharing pain."

Alabama's governor declined a more recent interview request on advice from legal counsel, as the dispute heads back to a federal court in Jacksonville, Fla., where a judge is expected to rule on the matter this spring.

Gov. Perdue said he's ready to negotiate with his counterparts in establishing a new agreement, but hasn't yet had much success.

"I remain committed to try to negotiate with our fellow states in a shared agreement," Gov. Perdue said. "But it takes more than one to negotiate."

Click here for a special On the Scene blog by Jonathan Serrie: "Man versus Mussel"