The Great Replacement

Nickajack Dam Solves Hales Bar Leaks

Nickajack is unique in that it is the only dam in the TVA system constructed specifically to replace an existing hydroelectric facility. Built in the mid-1960s, it replaced the aging and problematic Hales Bar Dam, located 6.4 miles upstream.

Hales Bar was the first main-river, multipurpose dam ever built on the Tennessee River. To improve navigation and provide electricity to Chattanooga, engineer Jo Conn Guild Sr. promoted the construction of a privately funded lock and dam in exchange for rights to the hydroelectric power. Congress passed enabling legislation in 1904, and with funding from Chattanooga entrepreneur Charles E. James and New York financier Anthony Brady, the Chattanooga and Tennessee River Power Co. was formed to oversee the project. Construction began in October 1905.

Difficulty at the Beginning

The construction of the dam and powerhouse was the largest development of its kind ever undertaken in the region. The dam was designed to be nearly a half-mile long and 63 feet high. The project employed more than 5,000 men and required the construction of a small village to house and feed workers. Originally slated for completion in 1909, the project faced numerous delays due to flooding and persistent leakage caused by the soft bedrock foundation.

The dam was finally completed four years later. The initial operation of the Hales Bar hydro plant on Nov. 13, 1913, was described by many as “the greatest celebration that Chattanooga has ever known.”

Unfortunately, leaks appeared almost immediately. In 1919, engineers attempted to reduce leakage by pumping hot asphalt into the foundation. The fix was temporary. By 1931, a study showed the dam was leaking at a rate of 1,000 cubic feet per second.

By then, the Chattanooga and Tennessee River Power Co. had merged with other companies to form the Tennessee Electric Power Co. (TEPCO), the largest private-sector electric utility in Tennessee at the time. TVA acquired Hales Bar Dam in August 1939 when it purchased TEPCO’s assets.

As part of TVA’s system of locks and dams, Hales Bar continued to be a challenge. By 1963, a Knoxville News-Sentinel article noted, “Ever since the dam was built, it has leaked. ... After spending well over $3 million over the years trying to plug the leaks, TVA has decided to chuck the whole idea, tear down the old dam and build a new one the agency can trust.”

Holding Together

TVA selected a site about 18 miles west of Chattanooga – where the river nears the Tennessee, Alabama and Georgia state lines – for the new dam. It was named Nickajack after an ancient Native American town. The new dam would generate more electricity than Hales Bar and, with two navigation locks, offer uninterrupted passage for river traffic.

Most importantly, Nickajack Dam would rest on a more stable rock formation than the cavernous limestone beneath Hales Bar, eliminating the leakage issues.

Construction began in 1964, and initial power operations started in February 1968. TVA built the two navigation locks first to ensure a steady flow of barge traffic. Salvageable parts – such as gate locks, spillway gates and generators – were moved from Hales Bar and repurposed.

As finishing touches were made to the $70 million Nickajack project in 1967 and 1968, the 1,000-foot-wide spillway of Hales Bar was demolished. Today, all that remains of Hales Bar is the powerhouse.