What if There Was Never a TVA?

TVA’s river management efforts help avoid major flooding in the Tennessee Valley by modeling what flooding would be like without the reservoir system.

Can you guess what the most flood-prone city in the Tennessee Valley is? It’s Chattanooga, and without the Tennessee Reservoir system, much of the city would be under water, much of the time. In fact, it is estimated that since Norris Dam was finished in 1936, around nearly $7.2 billion in flood-related damages have been averted in Chattanooga alone.

Broaden the scope to the rest of the Tennessee Valley, and that number grows to $7.9 billion. Add that to damages that didn’t happen to locations along the lower Ohio and Mississippi Rivers, and you’re looking at $8.6 billion in flood damages averted by the Tennessee Valley reservoir system.

TVA tracks what might have happened had it never existed as a way of keeping track of how well its system is operating. When flooding events do occur—such as the Chattanooga flood of March 1973, where the waters crested at 36.9 feet—we know that without the system of dams and reservoirs that flood would have been 15.5 feet higher. By the time the flood was over, it had caused $35 million in damages at Chattanooga. Had TVA not been there, that number would have been $465 million in property damages—which translates into nearly $2 billion of today’s dollars averted, just from the effects of that one flood!

Evaluating flood metrics keeps TVA engineers thinking how best to use the system, to prepare for every scenario and to keep the people of the Valley safe and dry no matter what the weather—and making sure we never forget the way things were.