The ACF River Basin originates in northeast Georgia, crosses the Georgia-Alabama border into central Alabama, and follows the state line south until it terminates in Apalachicola Bay, Florida. The basin covers 60 counties in Georgia, 10 counties in Alabama, and 8 counties in Florida. Extending a distance of approximately 385 miles, the basin drains 19,600 square miles.
The USACE Water Management Section of the Mobile District operates five federal reservoir projects: Buford Dam (Lake Lanier), West Point Dam, Walter F. George Lock and Dam, George W. Andrews Lock and Dam, and Jim Woodruff Lock and Dam (Lake Seminole) as components of the ACF system.
These are multi-purpose projects for which operations have been congressionally authorized either through the original project authorizations, or by subsequent congressional authorizations that apply generally to all USACE reservoir projects. The reservoir projects are operated in a balanced manner within the system to support all authorized project purposes and benefits within the ACF system to the extent practicable.
USACE does not prioritize the project purposes but does use action zones that have been defined for each of the major storage reservoirs in the ACF system—Lake Lanier, West Point Lake, and Walter F. George Lake. These action zones, which are outlined in the 1989 Draft Master Water Control Plan, are used to determine minimum hydropower generation and maximum navigation releases from conservation storage in the lakes while balancing the lake levels in a system-wide approach.
The guidelines in the Draft Water Control Plan reduce the amount of water available for augmenting navigation flows and other project purposes as drought conditions intensify in the basin. Ultimately, during times of drought, operations in support of navigation and hydropower may become very limited and recreation will be affected.
The strategy of operating the projects also calls for water to be taken first from storage in the lower lakes on the system and gradually pulling water from the upper lakes over time. Thus, Walter F. George, which contains most of the storage on the lower system because Lake Seminole does not have much storage, will be the first lake to be affected by operations on the system during periods of low water. If conditions remain dry, water will also be pulled from West Point Lake and eventually Lake Lanier. This is all done in accordance with the action zones and guidelines in the Water Control Manual, which attempts to equitably balance the lakes in the system. Varying hydrologic conditions throughout the ACF River Basin may result in the lakes getting out of balance; but, eventually, they will be brought back into balance according to the manual.
The Water Management Section makes daily decisions and coordinates regularly with representatives from the various areas for which the river systems are operated—hydropower, recreation, navigation, environmental, public affairs, and others areas—to exchange information concerning the operation of the river systems. Daily water management decisions are determined using the information obtained along with current project and basin data.
A weekly District River Report is prepared that summarizes the conditions in each of the river basins. Operation of the lakes on the ACF system is also guided by use of action zones. The action zones provide guidelines on meeting the project purposes for each lake. Congressional authorized project purposes on the ACF system include the following:
- Water Quality
- Flood Risk Management (Flood Control)
- Fish and Wildlife
Action zones have been defined for each of the major storage reservoirs in the ACF system—Lake Lanier, West Point Lake, and Walter F. George Lake. They are shown on the 5-week forecast charts on the ACF Basin Page. The zones are used to manage the lakes at the highest level possible for recreation and other purposes that benefit from high lake levels. The action zones also provide guidance on meeting minimum hydropower needs at each project and determine the amount of storage available for downstream purposes such as navigation.
The zones were derived on the basis of the past operation of the projects, which considered time of year, historical pool level/release relationships, operational limits for conservation, and recreational resource impact levels. The action zones are basic guidelines for operating the river system; however, there could be other factors and activities that cause the lakes to operate differently than the zones shown on the graphs. Some of those factors range from flood control actions, fish spawn operations, maintenance and repair of turbines, emergency situations such as drownings and chemical spills, drawdowns because of shoreline maintenance, releases made to free stuck barges, and other circumstances.
The federal lakes are operated to maintain their lake level in the same zones concurrently. However, because of the hydrologic and physical characteristics of the river system and factors mentioned above, there might be brief periods when one lake is in a lower zone than the other. If that occurs, efforts are made to bring the lakes back in balance with each other as soon as conditions allow. By doing so, effects on the river basin are shared equitably among the projects.
Water Control Manual
The authority for water control operations for USACE-owned and operated reservoir projects is contained in legislative authorization acts and referenced project documents. The public laws and project documents contain provisions for the development of a Master Water Control Manual and specific project Water Control Manuals and appropriate revisions and updates. A number of congressional authorizations apply to all federal reservoir projects, including the following:
- Flood Control Act of 1944 (P.L. 78-534)
- Fish and Wildlife Coordination Act of 1958 (P.L. 85-624)
- Water Supply Act of 1958 (P.L. 85-500)
- Federal Water Pollution Control Act Amendments of 1972 (P.L. 92-500)
- Endangered Species Act of 1973 (P.L. 93-205)
- Water Resource Development Acts
Without a comprehensive updated Master Water Control Manual, USACE runs the risk of, among other things, not providing sufficient water where needed (when needed to meet the authorized project purposes and the needs of stakeholders, whether domestic, municipal or industrial); adversely affecting endangered species; expending water resources too early, which reduces the ability to maintain the system to meet project purposes and the needs of stakeholders; and flooding people and facilities that are now within flood plains. This risk is due to changing conditions within the basin and at federal reservoirs which, if not accounted for, can affect water management decisions.
Hydrologists must consider and evaluate many factors to determine the appropriate management of water at each lake. In addition to the constraints of the authorized project purposes, they must consider power contract commitments, hydrologic and climatologic factors, downstream lake and basin wide conditions, potential threats of flood and drought, and lake levels.
The current Master Water Control Manual for the ACF River Basin was completed in 1958 and does not include Water Control Manuals for the West Point, Walter F. George, or George W. Andrews projects. Manuals were developed for individual projects in the ACF River Basin as they came on line or as operations changed to accommodate changing conditions within the system. EISs for the reservoir projects in the basin were prepared in the 1970s. The existing Water Control Manuals do not address water supply operations.
There was a need to develop an updated ACF Water Control Plan that incorporated the overall system management, and a draft was proposed in 1989 as part of the Lake Lanier post-authorization change report. This Water Control Plan described current system operations at that time but was never finalized because of litigation filed by the state of Alabama objecting to current and proposed changes to operations in the basin. However, USACE has been operating the ACF system under the draft 1989 Water Control Plan on an interim basis pending update of the Master Manual and individual project Water Control Manuals. The Water Control Manuals specific to each federal reservoir in the ACF River Basin are prepared as appendices to the Master Water Control Manual. The current project manuals are listed below.
- Appendix A - Jim Woodruff Reservoir
- Appendix B - Buford Dam
- Appendix C - Walter F. George Dam
- Appendix D - George W. Andrews Reservoir
- Appendix E - West Point Reservoir
The individual manuals typically outline the regulation schedules for each project, including operating criteria, guidelines, and rule curves as well as specifications for storage and releases from the reservoirs. The Water Control Manuals also outline the coordination protocol and data collection, management, and dissemination associated with routine and specific water management activities (such as flood control operations or drought contingency operations). Updates or revisions to the Water Control Manuals are typically integrated with the NEPA public involvement and documentation process.
The operational flexibility and discretion written into the manuals is necessary to balance the water management needs for the numerous and often competing authorized project purposes at each individual project with basin-wide water resource needs for areas throughout the ACF River Basin. Project operations must also be able to adapt to seasonal and inter-annual variations in flow and climatic conditions. Additional plans may also be developed for drought contingency operations or to respond to other emergency conditions.