Overview
Dillsboro Dam is one of a series of Duke Energy hydropower facilities along the Tuckasegee River. As private facilities, these dams require Federal Energy Regulatory Commission (FERC) licenses for operation. As part of a license, federal law requires operators to address impacts to fish and wildlife resources, including the limitation of up- and downstream fish movement caused by the dam. The removal of the Dillsboro Dam is seen as a large step toward addressing those impacts on the Tuckasegee River.

The removal of the dam was one of a suite of measures Duke agreed to in a 2003 settlement agreement signed by 16 stakeholders that included the U.S. Fish & Wildlife Service, North Carolina Wildlife Resources Commission, Eastern Band of Cherokee Indians, North Carolina Council of Trout Unlimited, and the towns of Sylva and Dillsboro. While the stakeholder process allowed input from a number of groups, federal law requires that input be solicited from the USFWS, and that the USFWS has the authority to prescribe fish passage for a licensed project.

Benefits to wildlife
The Dillsboro Dam is literally a wall across the river, preventing most fish, crayfish, and other stream animals from moving upstream and downstream. Dams effectively partition the stream into segments, splitting some aquatic wildlife populations while preventing others from accessing otherwise quality habitat. Although a stream may have pristine water quality, it’s useless to a fish that’s unable to access it.

Fish surveys documented greater fish diversity below the dam than above, including 10 species not found above the dam at all. Dam removal will provide access to upstream habitat not only to these fish, but to a pair of imperiled species in the Tuckasegee:  the federally endangered Appalachian elktoe mussel and the sicklefin redhorse fish. The elktoe is found both below the dam and above the reservoir behind the dam, so removal will help reconnect the bisected population. The migratory sicklefin redhorse is found in the lower reaches of the Tuckasegee River and is the focus of efforts to boost its numbers, including creating a population that will swim further up the river, into habitat made available by dam removal

Currently, nearly a mile of the Tuckasegee River sits impounded behind Dillsboro Dam. In this reach, sediment has settled on the stream bottom, covering the natural sand and rock substrate that supports native life.  Water at the bottom of the reservoir is also lower in oxygen and colder than free-flowing river water. The biological impact of the reservoir can be seen in the fact the Appalachian elktoe is found above and below, but not in the reservoir, and there are 11 species of fish in the reservoir behind the dam, while the river immediately below the dam has 38 species and the river stretch above has 24. Restoring the reservoir to a free-flowing river will make this portion of the river usable to a suite of native fish and other aquatic animals.

Benefits to wildlife-based recreation
Removing the dam will create a stretch of un-impounded river more than 29 miles long, providing boaters and anglers with more opportunity to enjoy a free-flowing river without having to portage around the 12-foot high dam. The restoration of the river behind the dam will open up habitat for native smallmouth and rock bass, and Duke Energy plans to install a boat access point upstream of the reservoir, improving access to this section of river.

Protecting wildlife during the process
In preparation for dam demolition, teams of biologists collected mussels from the area immediately below the dam and moved them upstream out of harm’s way.  In total, 1137 elktoes were collected. There were 54 specimens of wavy-rayed lampmussel also collected and moved. After the dam is removed and the river becomes stable, the mussels will be returned. In the long-term, the dam removal will open up new habitat for the mussels in the impounded part of the river behind the dam and will reconnect the bisected population, allowing them to interbreed, thus improving their genetic diversity, and with it, their ability to survive.

A short-term concern has been addressing the 100,000 cubic yards of sediment estimated to rest behind the dam. The Service tested the sediment, finding no contaminants of concern. 63,000 cubic yards of sediment were dredged and deposited at an upland site, with more to be removed during demolition. Most of the sediment not dredged will be stabilized in place on the newly exposed riverbanks, secured by landscaping using native plants. Some minor amounts sediment will be gradually released during demolition, eventually settling into the next reservoir downstream, one of the largest in North Carolina, where it will not have a noticeable impact.

Other steps taken to protect the stream and its wildlife during demolition include:

• * A meeting between the Fish & Wildlife Service and contractors working on the project to cover permit conditions and discuss any questions regarding measures to minimize or avoid impacts to Appalachian elktoes.
• * A qualified aquatic biologist will be present to monitor certain phases of demolition, including initial clearing and when any in-channel work is conducted.
• * Activities in the floodplain will be limited to those absolutely necessary to conduct the demolition.
• * All construction equipment should be refueled in a contained area outside the 100-year floodplain or at least 200 feet from all water bodies (whichever distance is greater).  Construction equipment will be inspected daily.  Hazardous materials, fuel, lubricating oils, or other chemicals will be stored outside the 100-year floodplain or at least 200 feet from all water bodies (whichever distance is greater), preferably at an upland site.
• * Stream-side vegetation will be maintained to the maximum extent possible, especially large trees. If stream-side areas are disturbed, they will be revegetated with native woody species as soon as possible.
• * Water clarity will be measured through the demolition.
• * The dam demolition is scheduled to proceed swiftly so that work in the river will be completed before spring spawning seasons.