Work at the Boone Dam near Kingsport. The cost of repairing the 65-year-old Boone Dam in Northeast Tennessee has risen by at least 50 percent from what the Tennessee Valley Authority estimated the fix would cost when the work began in 2015.
To shore up seepage problems in the TVA dam on the South Fork Holston River, TVA estimates it will now likely cost the utility $450 million and take another five years to complete. When work began, TVA estimated more than two years ago the Boone Dam repairs would cost between $200 million and $300 million and could be completed as soon as 2020.
TVA started investigating problems at the dam in October 2014 and launched construction of the composite seepage barrier in July 2015.
“As we got farther into the work there, we learned more about what is actually happening and that provided us the data to make a more robust estimate,” TVA President Bill Johnson told analysts during a conference call last week. “As design and construction plans are finalized for this ongoing, multi-year project, the estimated costs and duration are being refined and we expect to invest in the range of $450 million to secure the Boone project completion in 2022.”
The repair project is one of the most expensive ever at a TVA dam, but Johnson said the seepage problem at the Boone dam does not indicate any systemic or widespread problems across TVA’s network of 49 dams on the Tennessee River and its tributaries.