Hydrologic Modifications

A series of seven dams between the Georgia state line and the Coosa’s confluence with the Tallapoosa River, disrupt the natural flow of the Coosa for its entire length within Alabama’s borders.

Dramatic changes to the hydrology of the Coosa River began when the 1870 River and Harbor Act provided for a preliminary examination and survey of the navigation potential between Rome, GA and Greensport, AL (near Pell City) a distance of 180 miles. The survey suggested modifying the existing channel and extending navigation to Wetumpka. The final plan provided for a 4 by 100 foot channel from Wetumpka to Rome. Three locks and dams at Greensport and a dam near Riverside were authorized in 1876 and completed in 1890. A fifth dam near Wetumpka was never completed and abandoned in 1905. Channel work was carried out between 1877 and 1920 between Rome and Riverside. The Corps District Engineer recommended abandonment of the entire Coosa navigation project in 1931 and there has never been any maintenance of this project since.

Though the dream of the Coosa as a navigational waterway into the interior of Northeast Alabama was never realized, the era of hydroelectric power dams would forever alter the character of the mainstem of the Coosa River. Within Alabama most of the River has been dammed, considerably affecting species richness in the main stem. Alabama Power Company constructed and maintains 6 power dams on the Coosa.

The six mainstem reservoirs on the Coosa impound 238 miles of the Coosa and cover a total area of about 81,300 acres (FWS, ’98). Fisheries include those listed above as well as freshwater drum, smallmouth buffalo, catfishes, redeye bass (restricted to the head of those lakes where upstream tailwater influence is prevalent). Southern walleye have been reported from Logan Martin and Weiss Lake, and of course Lake Weiss’s crappie fishery is known by fisherman throughout the south. (FWS ’98)

The first of the seven dams on the Coosa (Weiss) is 60 miles below Rome and the last one 19 miles above the confluence with the Tallapoosa.

LAY DAM AND LAY LAKE
The Construction of Lay Dam is fairly significant in the history books because it marks the beginning of modern dam construction on the Coosa (a process that would forever change the character of the river) and also served as the maiden venture for the newly formed Alabama Power Company. Built in 1914, the state of Alabama had yet to see the scale of dramatic change that the

creation of a hydropower dam can bring. With a total drainage area of 9,087 sq miles, the lake covers approximately 12,000 acres and stores 262,306 acre/feet of water. The normal Summer Lake elevation is 396 feet.

This project is operated in a run-of-river mode, releasing outflows that approximate reservoir inflows on a daily basis.

MITCHELL DAM AND LAKE MITCHELL
Built in 1923.
Drainage area = 9,827 sq miles
Reservoir size = 5,850 acres
Reservoir storage = 170,422 ac/ft
Normal Summer Lake elevation = 312 ft

WEISS DAM and LAKE WEISS was built by Alabama Power Company in 1961. The reservoir drains an area approximately 5,273 sq miles.
Reservoir size = 30,200 acres
Reservoir storage = 305,815
Normal Summer Lake elevation = 564

Weiss Dam is the first of the seven Alabama Power company reservoirs on the Coosa River and sits very close to the Georgia / Alabama state line. The project is a peaking power operation. During typical operation the dam generates power for 1-6 hours per day during the week. There is no power generation on weekends. The Weiss tailwater is inundated by the Neely Henry impoundment eliminating the issue of minimum flows.

The entire flow of the Coosa is diverted through a canal leaving a 21-mile river segment adjacent to Weiss almost completely dry. This segment is often referred to as the Dead River and miraculously still harbors rare and endangered aquatic species.

LOGAN MARTIN DAM and LAKE LOGAN MARTIN was built by the Alabama Power Company in 1964. It has a drainage area of 7,743 sq miles, reservoir size of 15,263 acres, reservoir storage of 273,300 ac/ft. The normal Summer Lake elevation is 465 feet.

There is considerable siltation of the lake primarily related to development of the land upstream and around the reservoir.

NEELY HENRY DAM and LAKE NEELY HENRY was built by the Alabama Power Company in 1966.

Drainage area = 6,600 sq miles
Reservoir size = 11,200
Reservoir storage = 120,639
Normal Summer Lake elevation = 508 ft

Typically operated with a stable pool with infrequent fluctuations of a foot or more. Peaking facility. No power on weekends. Logan Martin lake inundates the tailwater.

Effects of erosion have been found to be especially noticeable following a period of prolonged drawdown.

JORDAN DAM AND LAKE JORDAN
Built in 1928. Bouldin built in 1967.
Drainage area = 10,165 sq miles
Reservoir size = 6,807
Reservoir storage = 235,780 ac/ft
Normal Summer Lake elevation = 252 ft

Jordan Dam is the only hydropower facility on the Coosa that has a minimum flow requirement. None of the dams on the Coosa have fish passage facilities.

There are three other significant dams in the Coosa River drainage that all occur on tributary streams in Georgia.

ALLATOONA DAM and LAKE ALLATOONA on the Etowah River was constructed by the Army Corps of Engineers in 1949. It sits about 48 miles above the mouth of the Etowah, near Cartersville, Georgia. With a total drainage area of 1,110 square miles, the lake covers 11,860 acres and holds 670,050 acre-feet of water. (GA DNR)

CARTERS DAM on the Coosawattee River was built by the Army Corps of Engineers in 1974. It sits about 26.8 miles above its mouth near Redbud, Georgia. With a total drainage area of 376 square miles, the lake covers just 3,220 acres, and holds 383,565 acre feet of water. Just downstream the Corps added a reregulation dam, CARTERS REREGULATION DAM which helps regulate the impact of hydropower releases.