A federal spending bill passed Thursday requires the U.S. Army Corps of Engineers to provide a report in the coming months that could further threaten Georgia’s use of Lake Lanier as a source of drinking water.

An amendment to the bill, passed nearly three months after Georgia lost a clutch battle in water-rights litigation with Florida and Alabama, requires the corps to provide a report to Congress in 120 days that shows how water is currently allocated in the Apalachicola-Chattahoochee-Flint and Alabama-Coosa-Tallapoosa river basins.

The Energy, Water and Related Agencies Appropriations bill could affect how operating manuals for the two basins are written and have serious repercussions for Georgians who rely on Lake Lanier for drinking water, said U.S. Rep. Nathan Deal, R-Gainesville.

The spending bill was passed by both the U.S. House and Senate this week.

Three representatives from Georgia, including Deal, fought the bill Thursday. U.S. Sen. Saxby Chambliss, R-Georgia, also voted against the spending bill.

“If you do the study at this point in time and do not consider human consumption and human use in the process, then you’re going to have a study, that for all intents and purposes, will, hopefully, be useless,” Deal said. “Because, at some point, the issue of human consumption is going to have to be addressed. And to spend a lot of money and to hurry the corps up to do something like this in a short time frame in which they will not be considering human consumption as part of this critical yield, I think, is a waste of money.”

The corps manages the two river basins based on decades-old operating manuals and staff experience. The manuals have not been updated since 1957 because of litigation between Georgia, Alabama and Florida over rights to the basins’ water.

Any study in the next few months affecting the basins’ management likely would not take into account the use of Lake Lanier as a source of drinking water, Deal said. A recent federal ruling in the tri-state water wars bars most of Georgia — and severely limits Gainesville and Forsyth County — from using the lake as such.

U.S. District Court Judge Paul Magnuson ruled in July that water withdrawal is not a congressionally authorized use of Lanier.

Magnuson’s ruling gives Georgia three years to stop using the reservoir for water consumption, negotiate with Florida and Alabama over the lake’s use or have Congress reauthorize the lake to allow water withdrawals.

Both Georgia officials and the corps have said they intend to appeal Magnuson’s ruling.

When the appropriations bill reached the floor of the House of Representatives on Thursday, Deal spoke against it, claiming the bill injects federal lawmakers into the tri-state water wars. He said it will be used against Georgia in litigation between the three states.

“To spend corps dollars calculating something that does not take into account the right of the people to drink the water that is in their state is unrealistic and is a true waste of federal money,” Deal said. “I find it quite ironic that the gentleman who injected this language into this bill just a couple of years ago was injecting language that directed the corps not to do these kind of studies. Isn’t it ironic how, all of a sudden, the positions have flip-flopped?”

By “gentleman,” Deal referred to U.S. Sen. Richard Shelby, R-Ala., a member of the Senate Appropriations Subcommittee on Energy and Water Development. The Alabama senator issued a news release Wednesday praising what he called the “Shelby Water Wars Amendment.”

“This legislative provision simply provides an understanding of how the water within the Alabama-Coosa-Tallapoosa and Apalachicola-Chattahoochee-Flint River Basins is currently being allocated,” Shelby said in a news release. “...I look forward to working expeditiously with my colleagues in Alabama, Florida and Georgia to ratify an equitable water allocation agreement that has been properly reached among the governors of each state and therefore is worthy of Congressional consideration and approval.”

In the past, Shelby has tried unsuccessfully to add language in corps appropriations bills that blocked the corps from updating its operating manuals for the two river basins. Most recently, Shelby introduced an amendment in 2007 that would bar the corps from using federal funds to update those manuals.

At that time, Georgia lawmakers fought Shelby’s amendment and were demanding new manuals, arguing that the corps’ current operating guidelines did not reflect the state’s growth. In early 2008, the corps began updating the manuals at the direction of U.S. Army Secretary Pete Geren, a process estimated to take three years.

“So now that (Alabama and Florida have) got this federal judge’s opinion in the Florida case, which they perceive as giving (Alabama) a tactical advantage, now all of a sudden, they’re wanting 120 days for them to start the process of updating the manuals — or at least a portion of it,” Deal said.

Technically, the only manual that is currently recognized for the Apalachicola-Chattahoochee-Flint River Basin is one that was written at the time Lake Lanier was completed in 1957. That manual was written before some of the projects, including Lake Walter F. George, were built. It also uses population data at the time when Georgia had 3.9 million residents, compared with the current 9.3 million. Atlanta’s population was nearing 1 million, compared with 4 million today.

An updated draft of the manuals was rejected in the late 1980s because of litigation between the three states.

Representatives for Shelby and U.S. Sen. Johnny Isakson did not comment by press time.

Times senior content editor Edie Rogers contributed to this report.