TVA Biologists Find Rare “Livers of the Rivers”

TVA biologists ended the summer by surveying the livers of Elk River tailwaters — a 130-mile stream that flows from the base of Tims Ford Dam in Lincoln County, Tennessee to Alabama’s Wheeler Reservoir.

The presence of the water-filtering pigtoes, heelsplitters, washboards and the federally threatened rabbitsfoot continue to provide evidence that the Elk’s aquatic ecosystem below the impoundment is improving since TVA’s 2004 decision to cease all generation on the river between mid-April to mid-October.

The new policy shift was part of an agreement between TVA and U.S. Fish and Wildlife Service to ensure the tailwaters below Tims Ford remain warm enough to support the spawning cycles of all native warm-water species.

USFWS is charged with the enforcement of the Endangered Species Act of 1973 and works in partnership with TVA, Tennessee Wildlife Resources Agency and other agencies to protect endangered species, such as the boulder darter, cracking pearlymussel and shiny pigtoe mussel that are present in the Elk. The Endangered Species Act is the same federal mandate that delayed the construction of Tellico Dam when University of Tennessee Ichthyologist Dr. David Etnier discovered the snail darter in the Little Tennessee River.

According to Todd Amacker, TVA’s Aquatic Endangered Species Biologist, the switch to flow-through operations at Tims Ford Dam established a slow, consistent release schedule throughout the spring and summer that more closely mimics a natural river

“The way that we used to operate Tims Ford Dam was by sending large plugs of cold water downstream,” Amacker said. “Once we made improvements to how we operate the dam, we saw an almost immediate recovery to the aquatic fauna below the dam.”

USFWS Biologist Andy Ford joined Amacker and the rest of TVA’s team in the summer mussel survey. Both mollusk experts agreed that protecting endangered mussels has a critical purpose:  it preserves water quality.

“Everything is connected,” Ford said. “Mussels are the sentinels of our rivers. They are the most sensitive to pollutants in our waters, and you want those bio-indicators so there is time to correct a water quality issue before it affects humans.

“Everyone supports clean water. I don’t care who you are,” he explained. “By looking out for these endangered species, we’re looking out for everyone.”

The Cost of No Generation

Elk River angler Rhonda Page supports protecting the boulder darter and rare freshwater mussels, but she’s also concerned about protecting the river’s trout fishery. It’s how she and her husband make their living as owners of Tim’s Flies and Lies Outfitters — a fly-fishing tackle shop, located in Normandy, Tennessee.

She said they opened their business in 2002, and once guided the cold, 14-mile-long stretch below the dam where TWRA annually stocks non-native species of rainbow and brown trout, which are recreational fish that can’t successfully reproduce in the Elk. But once TVA stopped generating in the summer, the warmer tailwaters shortened the trout fishery to nine miles and limited demand for her husband’s guide services.

“Back then, it was nothing to average a 100 fish in a day,” Page said.

The Pages no longer offer guided trips. Only tackle.

“The problem with the mandate is that when we get a bunch of rain like we’ve had this summer, TVA spills instead of generates,” Page said. “When you generate, that cold water comes off the bottom of the reservoir. When you spill, you’re dumping 80-degree surface water into a trout stream.”  

Trout become stressed when the water temperature reaches the mid-60s. They cannot survive at temperatures above 70 degrees.

Balancing Competing Needs

For an agency whose main priority is flood control, managing the Elk River tailwaters is all about balancing competing demands and fostering biodiversity. That’s why TVA River Management monitors dissolved oxygen levels and tailwater temperatures to ensure the health of the trout fishery.

During summer flood-control operations, TVA spills at a lower flow rate and extends release times over a period of days instead of hours. Spoon-feeding the warmer water into the stream prevents any sudden changes in tailwater temperature that is monitored by both TVA and TWRA at Farris Creek confluence. Farris creek is located nine miles downstream and marks the end of the trout fishery.

Fall generation resumes when the Farris Creek temperature monitor drops below 60 degrees.

While not ideal, compared to the 50-degree waters that Page and many trout anglers once enjoyed throughout the year, the balance between the competing needs of both the Elk’s native and non-native species allow both cold-water and warm-water fisheries to coexist.

And that’s a big deal for the local economy.

According to TVA’s 2021 Recreation Impact study, TVA’s 63 stream access sites across the Valley contributed $45 million in spending and attracted 565,663 recreational visitors. The sites are responsible for 624 Valley jobs and provide about $13 million in labor income.

Tennessee’s Trout Fisheries

TWRA is responsible for managing Tennessee’s trout fisheries. The state agency stocks about 2 million trout annually across  84 hatchery-supported streams, lakes and reservoirs.

“There’s only one species of trout that’s native to Tennessee and that’s the brook trout, which is only found naturally in a few streams in the southern Appalachians,” TWRA said. “Instead of having to drive several hundreds of miles to fish for trout, our stocking program gives anglers a close-to-home fishing opportunity.”

Biologist Dave Harrell is an avid fly fisherman who is a member of Trout Unlimited’s Clinch River chapter. He volunteers as an instructor for Project Healing Waters, which is a non-profit organization that uses trout fishing as physical and emotional rehabilitation for disabled active military service personnel and veterans. In addition, he also serves as a volunteer instructor for Casting for Recovery, another non-profit that teaches women who have been touched by breast cancer how to fly fish.

“There’s a lot of good that comes from our trout fisheries, and it’s not all economic,” Harrell said.

A Rare Find

Protecting the Valley’s waterways is a big job that requires partnership. To conduct the recent five-day mussel checkup on the Elk, biologists from USFWS and TWRA joined TVA to comb the gravel bottom of the river. The efforts took a total of 60 hours.

The team surveyed five sites and identified 25 species of mussels: Tennessee pigtoe, pistolgrip, round hickorynut, fragile papershell, mucket, spike, mountain creekshell, three-ridge, slabside pearlymussel, washboard, mapleleaf, deertoe, longsolid, rabbitsfoot, Tennessee clubshell, wavy-rayed lampmussel, purple wartyback, pimpleback, pink heelsplitter, three-horn wartyback, butterfly mussel, pocketbook, plain pocketbook, flutedshell, snuffbox (pictured below).

And to the team’s surprise, they plucked a pristine shiny pigtoe mussel from the river that measured 36.5mm. The USFWS used a genetic swab to confirm the identification made in the field. The rare find was officially documented as the first siting of the endangered species in the Elk River since the 1970’s.

“It’s a privilege any time you get to see a species that is only known from a few places on planet Earth, especially working with aquatic species that aren’t found outside of Tennessee or Alabama,” Amacker said. “But to find a species that was thought to be extirpated completely from the Elk River is extra special. I think what we found is further proof that the way we are now managing the Elk is working.”