The TVA system of multipurpose dams and coal-fired generating plants expanded enormously in the ‘50s. In 1952, the final width and depth of the navigation channel was achieved throughout the Tennessee River. By the end of the decade, 28 major dams straddled the Tennessee and its tributaries and shoreline investment mushroomed from only $60 million in the two previous decades to $669 million in the 1950s.
In 1957, the Tennessee Valley endured the longest rainstorm in recorded history. A record flood-crest reduction of almost 22 feet prevented $112 million in
potential damage, overshadowing the $33 million in damages averted during three floods in the forties.
Seven large coal-fired generating plants were built during the 1950s, eventually providing more than double the generating capacity of the hydro system. Some in Congress began to question the need for taxpayer funding for power plants that did not offer the multipurpose benefits of the reservoir system.
In 1959, after years of debate, Congress authorized TVA to finance its power operations through bond sales. These bonds were backed, not by the credit of the U.S. Government, but by the revenues from the sale of TVA power. The amendment making TVA self-financing also required TVA to repay the funds Congress already had invested in the TVA power system, along with an annual return on the outstanding investment. It also defined an area now known as “the Fence,” which established limits of the TVA service territory.