Although as far as dams go the Tellico Dam is not a terribly impressive structure (it's a relatively small concrete spillway with a gentle earth embankment), its history is unique. Tellico Dam was one of the first controversial dam projects in the country. Construction of the dam was delayed when the discovery of the Snail Darter, an endangered fish, was found in this portion of the Tennessee River. The case made it to the U.S. Supreme Court in the Case Tennessee Valley vs. Hill. Eventually Congress waived the Endangered Species Act to allow construction of the dam.
See
the Tellico Dam Wikipedia entry for more information.
Note: Although the dam itself does not produce power, it redirects the flow of the river to the larger Fourt Loudon Dam that does do this.