The Cobb County-Marietta Water Authority (CCMWA), City of Cartersville, and Bartow County rely on Allatoona Lake to meet their municipal and industrial water supply needs. CCMWA withdraws water stored in Allatoona Lake under a storage contract it signed in 1963, which lets CCMWA store up to 13,140 acre-feet of water in the reservoir. (An acre-foot is the volume of water required to cover one acre in water one foot deep, or about 325,851 gallons.) The City of Cartersville has two contracts with the Corps (one signed in 1966 and another signed in 1993), which give it the right to store up to 6,371 acre-feet of water in Allatoona Lake.
In 1981, CCMWA requested to contract for more storage in Allatoona Lake, asking the Corps to move forward “as rapidly as possible” on the request. The Corps completed its review of CCMWA’s request in 1989. At that time, the Corps proposed to “reallocate” 34,864 acre-feet of storage in Allatoona Lake so it could be used by CCMWA and others for water supply storage. The Corps’ proposal was based on an environmental study and its determination that there would “be no significant environmental impacts.”
Alabama sued the Corps in 1990 to block it from finalizing the plan. Like the ACF litigation filed by Alabama, Florida, and others, Alabama’s claims in the ACT Basin were ultimately dismissed in 2012.
In the intervening years, CCMWA and its retail customers worked to reduce water supply needs through conservation. CCMWA also invested heavily in projects to generate “made inflows” to increase the amount of water available from CCMWA’s storage in Allatoona Lake. Made inflows consist of reclaimed water returned to a reservoir for reuse and releases of water stored in other water supply reservoirs. These projects minimize environmental impacts and maximize the use of existing infrastructure by augmenting the amount of water flowing into CCMWA’s storage space in the reservoir.
For example, each day about 17 million gallons of highly treated, reclaimed water is collected and returned to Allatoona Lake for reuse. Likewise, CCMWA has constructed the Hickory Log Creek Reservoir upstream of Allatoona Lake. This project releases water for withdrawal by CCMWA to supplement its Allatoona Lake supplies.
In November 2014, the Corps released an updated master water control manual and Environmental Impact Statement (EIS) for the ACT Basin. Unfortunately, the updated manual and EIS failed to address CCMWA’s request for more storage and many other issues related to water supply. The updated manual was formally adopted in May 2015 without correcting these deficiencies.
Failure to Act Lawsuit (resolved)
In November 2014, following release of the Corps' EIS, the State of Georgia, the Atlanta Regional Commission, and CCMWA sued the Corps to compel it to act on water supply issues at Allatoona Lake.
In September 2017, the district court ruled in favor, finding that the Corps’ failure to respond to the Georgia Parties’ water supply requests at Allatoona Lake was unlawful. The district court ordered the Corps to respond to the water supply requests by August 2021. The case (the “Failure to Act Lawsuit”) was State of Georgia v. U.S. Army Corps of Engineers, Civil Action No. 1:14-cv-3593 (N.D. Ga.).
Storage Accounting Lawsuit (resolved)
In 2017, CCMWA sued the Corps over its refusal to honor CCMWA’s rights to “made inflows” — reclaimed water returned to the lake and releases from the Hickory Log Creek Reservoir — that had been allocated to CCMWA by the State of Georgia. CCMWA and the Corps signed a settlement to resolve CCMWA’s legal claims. The settlement agreement required the Corps to reconsider its practices and study the environmental impacts of honoring CCMWA’s water rights. The case (the “Storage Accounting Lawsuit”) was CCMWA v. U.S. Army Corps of Engineers, Civil Action No. 1:17-cv-400 (N.D. Ga.).
The Corps’ Reallocation Study
The Corps prepared a “Reallocation Study” to comply with the court’s order in the Failure to Act Lawsuit and its settlement agreement in the Storage Accounting Lawsuit. This study, which extended over three years, evaluated the impacts of meeting Metro Atlanta's water supply needs from Allatoona Lake and honoring CCMWA’s rights to made inflows.
Based on a detailed Environmental Impact Statement, the Corps signed a Record of Decision on August 30, 2021, granting Metro Atlanta’s water supply requests from Allatoona Lake. The decision confirms that Metro Atlanta’s projected 2050 water supply needs from Allatoona Lake of 94 million gallons per day will be met, explaining that “exhaustive analysis” by the Corps shows meeting these needs will have “no significant adverse impacts to federal purposes” and no “appreciable effects on flows at the Alabama-Georgia state line, drought triggers, or water quality.”
The decision reallocates more storage space in the reservoir to meet the projected water needs of the City of Cartersville and Bartow County through 2050. When combined with the existing water supply storage space in the reservoir, about 5.85 percent of the usable storage and about 12 percent of the conservation storage in Allatoona Lake will be dedicated to water supply. This means that about 88 percent of the reservoir’s conservation storage will remain available to meet other objectives like recreation, hydropower, navigation, and fish and wildlife conservation.
Additionally, and perhaps more significantly, the decision recognizes CCMWA’s right to impound and withdraw made inflows to Allatoona Lake. Made inflows are a critical part of Metro Atlanta’s long-term water supply plan because they increase the amount of water flowing into a reservoir, thus letting water providers meet growing needs and improve water supply reliability by engineering projects to put more water back into existing reservoirs.
The decision recognizing CCMWA’s rights to made inflows marks a sea-change in Corps water policy. It will strongly incentivize more water reuse in Metro Atlanta, enhance the resiliency of the region’s water supply, and maximize the use of existing reservoir storage space, thus avoiding economic and environmental impacts from constructing more and unnecessary water supply infrastructure.
Alabama et al. Lawsuit (ongoing)
Separately, in May 2015, the State of Alabama and Alabama Power also sued the Corps in federal court in Washington, D.C. to challenge the Corps’ 2015 decision to revise its ACT Master Water Control Manual. These suits challenge the Corps’ compliance with NEPA, as well as the operational rules adopted by the Corps. Further, in November 2022, Alabama was granted permission to add new claims challenging the Corps’ 2021 Record of Decision granting water supply requests at Allatoona Lake and honoring CCMWA’s rights to made inflows. The consolidated case (the “Alabama Parties’ Lawsuit”) is Alabama et al. v. U.S. Army Corps of Engineers, Civil Action No. 1:15-cv-696 (D.D.C.). The cities of Montgomery and Mobile, Alabama have also intervened in this case, as have the State of Georgia, the Atlanta Regional Commission and the Cobb-County Marietta Water Authority. This case remains pending in Washington, D.C.