ATLANTA — The U.S. Army Corps of Engineers said Wednesday it will conserve water during the ongoing drought by restricting the flow from a major reservoir that serves as the main water supply for Atlanta.
    Army officials plan to cut the flow of water from Lake Lanier from 750 cubic feet per second to 650 cubic feet per second, Army Corps spokesman Pat Robbins said. While Robbins said the reduced flow into the Chattahoochee River would not be perceptible to the eye, it is intended to slowly build up the water in the reservoir in case river systems run low in the coming months.
    The dam was holding roughly 1,058 feet of water Wednesday — just a few feet above levels last seen during a prolonged drought that started in 2007.
    Water from Lake Lanier drains into the Chattahoochee River, which curves around Atlanta and flows along the border of Alabama and Georgia. The Chattahoochee and Flint rivers merge near the Florida line to form the Apalachicola River. Additional dams south of Lake Lanier help regulate the flow of water across the entire basin.
    "If the lower lakes don't get any additional rain, you've got to have water from somewhere," Robbins said. "And that's the purpose of holding it back at Lake Lanier — it's for the health of the system."
    Georgia authorities asked the Army Corps to restrict flows from the hydroelectric dam at Lake Lanier earlier this month. The Army said it reviewed information supplied by Georgia officials and determined the reduced flow of water into the Chattahoochee River would not harm the environment.
    "We did it because the outlook is for a warm, dry winter and we're already experiencing effects of the drought that we're in," said Jim Ussery, the assistant director of the Georgia Environmental Protection Division. "We wanted to conserve as much flow as we could, as much storage as we could in Lake Lanier."
    Sensors relay water quality information to Georgia authorities at several points on the Chattahoochee. If those sensors detect problems such as too little dissolved oxygen in the water — a problem harmful to fish — flows from the dam can be raised, Ussery said.
    Army officials said they made a decision to restrict water flows during a 2008 drought and have already taken similar steps along the Alabama, Coosa and Tallapoosa river system that is shared by Georgia and Alabama.
    Georgia is locked in a long-running legal dispute over metro Atlanta's use of Lake Lanier, which serves as the main water supply for roughly 3 million people. Alabama and Florida say Congress never authorized metro Atlanta to pull drinking water from the reservoir and that the city uses too much, harming the environment and industry downstream.
    The 11th U.S. Circuit Court of Appeals recently ruled in favor of Georgia. Alabama Gov. Robert Bentley has said his state will appeal the case to the U.S. Supreme Court.
    Florida did not oppose the flow restrictions announced Wednesday from Lake Lanier, said Jennifer Diaz, a spokeswoman for Florida Department of Environmental Protection. Officials in Alabama did not return calls seeking comment.