sentences:  It began operation on November 13th, 1913.In 1939, the Tennessee Valley Authority assumed control of Hales Bar Dam after purchasing TEPCO's assets.TVA spent two decades trying to fix a leakage problem that had plagued Hales Bar since its construction, but after continued leakage, and after it was determined that expanding the dam's navigation lock would be too expensive, TVA decided to replace the dam by building Nickajack Dam downstream.