Hydrologic Modifications

There are nine dams on the mainstem of the Tennessee River. The first four dams are in Tennessee and in descending order are the Fort Loudon Dam, Watts Bar Dam, Chickamauga Dam, and the Nickajack Dam. The next three dams are located in Alabama and include the Guntersville Dam, Wheeler Dam, and Wilson Dam. A large portion of the Pickwick Lake reservoir formed by Pickwick Dam in Tennessee backs up into northwest Alabama.

GUNTERSVILLE DAM, which forms LAKE GUNTERSVILLE, is located about 7 miles northwest of the town of Guntersville, Alabama in the Sequatchie Valley Province. TVA began construction of the dam in December 1935 and it was completed in January 1939. John Gunter, an early settler of the area lends his name first to the city of Guntersville, and then to this dam, built so close by. The dam sits 349 river miles from the mouth of the Tennessee River.

The Guntersville Lake watershed encompasses 2,669 square miles and the lake itself covers 67,900 acres making it the second largest of all TVA operated projects (Kentucky Reservoir is first with 160,300 surface acres). The shoreline covers 949 miles. Most of the flow into Guntersville Lake is released from Nikcajack Dam in Tennessee (approximately 37,200 cubic feet per second cfs), with an additional 4,600 cfs generated by tributaries into the reservoir. The reservoir stretches for 76 miles in length. (TVA-Guntersville)

Guntersville Lake has many public use areas including 2 state parks, 13 city or county parks, 4 state wildlife centers, 8 campgrounds, 5 camping resorts, 16 marinas, 43 boat ramps, 30 public access areas, and 23 commercial recreation areas.

In 2001, TVA owned and managed 40,236 acres of land on the reservoir.

The Lake has an average depth of only 15 feet and a maximum depth of 60 feet. The reservoir is sometimes characterized as a run of the river operation because it has an average retention time of only 12-13 days, and a small winter drawdown of only 2 to 3 feet. (TVA-Guntersville)

WHEELER LOCK AND DAM, which forms WHEELER LAKE, is located approximately 15 miles east of Wilson Dam. Wheeler Dam was the very first project taken on by the Tennessee Valley Authority just six months after Franklin D Roosevelt created the organization in 1933. Wheeler was a pivotal dam in inundating the Muscle Shoals, a major hindrance to navigational travel on the Middle Tennessee.

The dam was named after General Joseph Wheeler, also known as Fighting Joe Wheeler, who was a Confederate General during the Civil War. Wheeler’s home was located about 17 miles from the present dam site. Wheeler became an Alabama congressman and in 1898 wrote the first bill providing for the development of Muscle Shoals for navigation as well as hydropower. Though the project didn’t materialize, this bill was the first of many that led to the formation of the Tennessee Valley Authority.

Begun in January of 1933, Wheeler Dam was completed in 1936. It was the first of eight dams that TVA constructed on the Tennessee River. The lake covers 67,100 acres and creates a shoreline of 1,063 miles. TVA originally purchased 103,400 acres of land that may have been damaged as a result of the formation of the reservoir. Most of this land was inundated by the reservoir itself. Of that acreage remaining, these areas were either transferred to other agencies, managed for industrial development, leased for agriculture, or sometimes sold outright. TVA now owns and manages 11,284 acres of land around the reservoir for recreation, industrial development, navigation, wildlife and forest management, cultural and environmental preservation, and agriculture. These lands account for 335 miles or 31% of the shoreline. (Tenn Dams and Wheeler Land Plan)

Today, the industrial facilities in Decatur represent the largest concentration of waterfront industrial development in the Tennessee Valley Region. (Wheeler Land Plan)

Wheeler Lake forms a 74-mile long channel maintaining a depth of 9 feet all the way to Guntersville Dam. Wheeler Lake receives an average of 41,800 cfs from releases from the Guntersville Dam.

WILSON LOCK AND DAM, which forms WILSON LAKE, is located in the Shoals Area of Northwest Alabama. It was named for President Woodrow Wilson. It was the first dam constructed on the Tennessee River. Construction began in 1918 and was completed during 1924. It was constructed and operated by the U.S. Army Corp. of Engineers until the creation of the Tennessee Valley Authority in 1933. TVA added 13 generators, which produces more electricity than any other dam on the Tennessee River. The lake creates a shoreline of 154 mile and covers 15,500 acres.

TVA owns very little land surrounding this reservoir. TVA only purchased flowage easements or the right to flood shoreline up to a specific elevation. (Wheeler Reservoir Plan)

Though PICKWICK DAM is located in Tennessee, much of PICKWICK LAKE extends into Alabama. This reservoir began to fill in 1938 and as it did portions of the towns of Waterloo in Lauderdale County, Alabama and Riverton in Colbert County, Alabama were lost to the reservoir.