sentences:  In the 1960s, TVA began expanding the size of its dam locks to accommodate the increase in river traffic the Tennessee Valley had experienced since the end of World War II.A study in 1963 suggested that expanding the size of the Hales Bar lock would be extremely expensive, and considering the continued expenses involved with leak repair, TVA decided that would be more practical to replace the dam altogether.Nickajack Dam was authorized in January 1963 and construction was completed December 14, 1967.