Dedicated to the Conservation of Southeastern Fishes
Stream Shows Signs Of Life
September 10, 2006
Release from: Morgan Simmons
TELLICO PLAINS, Tenn. - Fisheries biologist Jim Herrig lowered the probe into McNabb Creek and waited for the results. When the screen flashed a pH reading of 6.9 - just a hair below neutral on the acidity scale - he couldn't resist a smile.
Know News (Tennessee)
"This," said Herrig, "is what a mountain stream should be."
McNabb Creek is making a lot of people smile lately. Located in the Cherokee National Forest, the stream is a tributary of the North River, which in turn feeds the Tellico River.
In 1977, McNabb Creek was severely impacted when construction of the Tellico-Robbinsville Road - also known as the Cherohala Skyway - cut through Anakeesta rock, causing acids and toxic metals to leach into McNabb and other nearby streams every time it rained.
For two years, the project was shut down while the Federal Highway Administration tried to mitigate the damage. More than $2 million was spent on treatments, most of them aimed at blanketing the crushed Anakeesta rock used as road fill with a layer of fiberglass fabric, limestone and soil.
Over time, McNabb Creek recovered enough to support four species of fish, but no reproduction was documented. In 2005, to accelerate the stream's comeback, the U.S. Forest Service dumped 7 1/2 tons of 99 percent pure limestone sand at the headwaters of McNabb Creek so that every time it rained, the sand washed downstream to neutralize the acid runoff.
In August 2005, the U.S. Forest Service, the Tennessee Wildlife Resources Agency and Trout Unlimited removed 220 rainbow trout from McNabb Creek to make conditions more favorable for brook trout, the only trout native to the eastern United States. They also collected 180 southern strain brook trout from a nearby stream and released them into McNabb Creek.
This summer, for the first time in almost 30 years, biologists saw clear evidence of brook trout reproduction in McNabb Creek.
For Robert Wilson, president of the Appalachian Chapter of Trout Unlimited, the news couldn't have been sweeter.
"Brook trout are one of our most beautiful fish," Wilson said. "Fishing for them takes you to smaller streams in the rhododendron thickets that are off the beaten path. It's the opposite of fishing big, open water."
All told, six out of the eight chapters of Trout Unlimited in Tennessee worked on the McNabb Creek project. Forest service officials say overall fish numbers in the creek still are about one-tenth of what they should be and that McNabb won't be open to fishing until at least 2008 when brook trout reach their capacity.
Traces of the limestone sand used to treat acid runoff in McNabb Creek are still visible along the Tellico-Robbinsville Road a few miles west of the Tennessee-North Carolina line.
There, at an elevation of about 3,400 feet, is where McNabb Creek gets its start. The U.S. Forest Service dumped the sugary-fine sand at nine points - mostly at the mouth of culverts that funnel water away from the roadbed and down the mountain.
On a recent visit to the treatment site, Herrig took a pH measurement at a pool of water barely larger than a birdbath. This was ground zero for McNabb Creek. Located at the base of the roadbed, the pool was fed by water draining out of the fill dirt, which was piled as deep as 100 feet beneath the highway.
After construction of the Tellico-Robbinsville Road resumed, crews built bridges to span stream drainages instead of filling them with the Anakeesta spoils from the road cuts.
Herrig said Virginia and West Virginia have used similar limestone sand treatments to neutralize the effects of acid precipitation.
"The beauty of this treatment is that very little sand moves during base flows," Herrig said. "It only washes down during rain events, which is when the stabilizing effects of the limestone is needed most."
Exposed Anakeesta has created pollution problems with a number of highway projects in the Southern Appalachians, including U.S. Highway 441 (Newfound Gap Road) in the Great Smoky Mountains National Park.
Rainwater draining directly off the roadside Anakeesta cliffs along the Tellico-Robbinsville Road can have a pH value of 3.5 - almost the same acid level as vinegar or lemon juice.
Herrig said the limestone sand treatment is expected to be effective from three to seven years and that monitoring will determine when, or if, more treatments are needed.
"When people can fish McNabb Creek and consistently catch brook trout, then I'll be happy," Herrig said.