The removal of the dillsboro dam: The challenge of success

Duke Energy Carolinas, LLC (Duke) operates the Dillsboro Hydroelectric Project (Tuckasegee River, western NC) under a license from the Federal Energy Regulatory Commission (FERC No. 2602).  Duke proposed to surrender the License and subsequently removal the low-head dam and powerhouse as part of Settlement Agreements addressing continued operation of other Tuckasegee River Projects.  This project would provide mitigation for fish passage at the upstream projects and instream flow relief at specific bypassed reaches.  The removal would allow full aquatic resource access (including listed species and a coldwater fishery) to an additional 9.5 miles of river and ultimately restore 4,220 feet of the river.  This success story is not without its environmental, regulatory and engineering challenges.  Foremost of these challenges was the relocation of federally listed mussels and the removal of 70,000 cubic yards of sediment.  In addition to the FERC surrender order, section 401 water quality certification, several section 404 permits, and a dredging permit were required before the dam removal.  Engineering challenges include staged removal, water level management, bank stabilization, and site restoration.  Several legal challenges were associated with the dam removal.  In spite of these challenges, the dam and powerhouse were successfully removed in January/February of 2010.