The ruling comes amid tense negotiations among the states' governors over water sharing during a record drought.
The 2003 agreement with the Corps would give Georgia about a quarter of Lake Lanier's capacity over the coming decades and is the foundation of Georgia's long-term plans for supplying drinking water to the rapidly growing Atlanta region.
Alabama and Florida challenged the pact, arguing that Georgia doesn't have any legal right to the federal reservoir, which was initially built for hydropower. The withdrawals would dry up river flows into their states that support smaller municipalities, power plants, commercial fisheries and industrial users like paper mills.
