The Flood that Never Was
When devastating flooding conditions hit, TVA is ready to spring into action. Here's an example of one year in which TVA was able to transform floodwater into record-breaking amounts of clean hydropower.
In January of 2013, a rain forecast of two inches turned into a disaster overnight. The Valley was quite literally drenched—and had received enough rainfall to flood major cities. Without intervention, Lenoir City could have been 16 feet under water, Elizabethton could have been 6 feet under water, Kingsport could have been 8 feet under water and Chattanooga could have been a whopping—and devastating—20 feet under water.
TVA River Operations went to work—having already prepared for such an event through the fall’s controlled drawdowns, preparing for winter rain. By all accounts, however, this was a doozy. This was the most rain anyone has seen in almost 60 years. Just under 10 inches fell during a weeklong rain event in Chattanooga, causing rivers and creeks to swell. Most of Tennessee was under 6 to 8 inches, but mountainous locations along the North Carolina border were subjected to 20 inches in some cases. With winter still ahead, it was time to release some water down the system.
Turning on the Turbines
River Operations was up to the task. TVA began releasing water through its turbines at full capacity. But that wasn’t enough, so they began to spill—letting water run over the dams at an even faster rate to outpace the flooding. Spilling—never popular among dam operators who would rather use the water to generate power operations—is an option of last resort. Yet spilling ruled in the Valley for 25 of the 31 days of January—a good indicator of the type of flood we were dealing with, and also the amount of flood storage space available in TVA’s reservoir system.
At the height of the flood, all of TVA’s 109 conventional hydro generating units were online and spinning simultaneously to generate clean, low-cost for the Valley, even as it saved millions of people from the trauma of flooding. By the end of February 2013, TVA had generated the most hydropower in its history 3,300 MW—enough to power 1.8 million homes.
Flooding was controlled, with modeling showing 20 feet of flooding averted in Chattanooga, 8 feet in Kingsport, 6 feet in Elizabethton, and 16 feet in Knoxville. Each of these cities were spared major structural damage—not to mention flooding in smaller towns. Estimates put the total spared damage in the Tennessee for that one flood averted at just over $800 million dollars.