The boulder darter isn’t much to look at—a dull silver-brown fish barely the length of an adult man’s finger. But it’s a rarity, a fish found only in the Tennessee Valley, in the Elk River below Tims Ford Dam. So rare, in fact, that it’s protected by the Endangered Species Act.
The Elk River is an area known for its aquatic diversity, home to a wide variety of mussels, snails and sport fish that thrive in relatively warm water.
But it’s also home to a regionally important trout fishery, stocked by the Tennessee Wildlife Resources Agency, a put-and-take fishery maintained during summer months. The trout thrive in the cold water released through the Tims Ford Dam; however, the drop in temperature put stress on the boulder darters, as well as several species of endangered mussels that inhabit the tailwater. What to do?
TVA undertook a study with the U.S. Fish and Wildlife Service and agreed to modify its hydropower operations at Tims Ford Dam to warm up the temperature of the tailwater to help protect and promote the recovery of the boulder darter, endangered mussels and other warm-water sport fish downstream of the cold-water trout fisheries.
It’s a win-win. Temperatures at the Elk River Mile 124 are ideal for trout, while downstream at the Elk River Mile 93 gauge they run a good 20 to 30 degrees warmer—ideal for endangered boulder darters, mussels, snails and sport fish to not only survive but thrive.