The Draft Environmental Impact Statement (DEIS) presents the results of the USACE’ analysis of the environmental effects of the Proposed Action Alternative (PAA) for the ACT River Basin Master Water Control Manual. Under the PAA, USACE would continue to operate the ACT as a system in a balanced manner to achieve all authorized project purposes. Operations under the PAA include the following:
• Implement a revised drought plan with enhancements recommended by USFWS.
• Provide for seasonal navigation releases, coupled with seasonal maintenance dredging, to support commercial navigation in the Alabama River for a 9.0-ft or 7.5-ft channel depth as long as sufficient basin inflow above the APC projects is available. When sufficient flows cannot be provided to continue to support a minimum 7.5-ft navigation channel, navigation could be impeded and flows at Montgomery would be reduced to 4,640 cfs (7Q10). If one or more of the drought operations triggers (low basin inflows, low composite conservation storage, or low state line flows) are met, minimum flows at Montgomery would be dropped below 4,640 cfs in accordance with specific protocols developed collaboratively between the USACE and APC (discussed in detail in Section 5 of the DEIS).
• Alabama Power Company (APC) projects on the Coosa and Tallapoosa Rivers would continue to operate under their current Federal Energy Regulatory Commission licenses with specific operational requirements.
• The APC project, H. Neely Henry Lake (Coosa River), which operates with a revised guide curve under a FERC license variance (with USACE concurrence) would continue to operate under its revised guide curve.
• Specified flow requirements at Allatoona Lake would continue to provide for a 240-cfs minimum flow.
• The existing guide curve at Allatoona Lake would be revised to implement a phased fall drawdown period from early September through December. Refined operations at Allatoona Lake would include use of four action zones shaped to mimic the seasonal demands for hydropower. Modifications to the hydropower schedule would be put in place to provide greater operational flexibility to meet power demands while conserving storage. Specifically, under the PAA, hydropower generation would be reduced during annual drawdown in the fall (September through November).
•The current minimum flow requirement would remain 240 cfs from the Carters Reregulation Dam. Refined operations at Carters Lake would include the use of two action zones to manage downstream releases. The top of the new action zone 2 begins at elevation 1,066 ft in January, increasing to 1,070.5 ft in May, dropping to 1,070 ft by October, and returning to elevation 1,066 ft through December. When Carters Lake is in action zone 1, minimum flow releases at Carters Reregulation Dam would be equal to the seasonal minimum flow. Those minimum flow releases are based on the mean monthly flow upstream of Carters Lake. If Carters Lake elevations drop into action zone 2, minimum flow releases from Carters Reregulation Dam would be 240 cfs.
• The USACE reserves 6,371 ac-ft of storage space in Allatoona Lake for water supply for the City of Cartersville, Georgia and 13,140 ac-ft for the Cobb County Marietta Water Authority. Total storage space allocated to water supply is 19,511 ac-ft.
• The USACE reserves 818 ac-ft in Carters Lake for water supply for the City of Chatsworth, Georgia.
• The USACE would continue to manage fish spawning operations at 1 Allatoona Lake. During the largemouth bass spawning period, from March 15 to May 15, the USACE seeks to maintain generally stable or rising reservoir levels at Allatoona Lake. Generally stable or rising levels are defined as not lowering the reservoir levels by more than 6 inches, with the base elevation generally adjusted upward as levels rise from increased inflows or refilling of the reservoir.
• The USACE would continue migratory fish passage operations at Claiborne Lock and Dam and Millers Ferry Lock and Dam, as stated under the No Action Alternative.
One alternative available to the USACE is to continue with current operations. This is called the No Action Alternative (NAA). This would primarily mean that no revised drought plan would be implemented, there would be no modification to the guide curve at Allatoona Lake, no modification to action zones at Carters Lake, and there would be no implementation of seasonal minimum flows at Carters Lake. Hydropower production reduction during the Fall drawdown would not be implemented at Allatoona Lake.
Neither the PAA nor the NAA would alter existing water supply storage allocations, APC project guide curves, fish spawning or fish passage operations.