By Dave Ongie
It was three years ago this month that experts from the Tennessee Valley Authority began formulating a plan to repair the seepage in the earthen embankment underneath Boone Dam.
The Boone Dam Project, as it has come to be known, has presented a unique set of challenges for the TVA employees charged with repairing the dam and returning the water level in the Boone Lake reservoir to its normal levels. Sam Vinson, the project coordinator for the Boone Dam Project, said the urgency of the situation combined with the uncertainty of what it would take to seal up the earthen embankment under the dam ultimately led to an unorthodox approach by TVA’s experts.
“Typically you plan your work, you design your work and then you build your work,” Vinson said during a phone interview last Friday. “For us at Boone, because of the urgency, we had to combine all of those phases. So in our process, we would actually plan something, design it, go start building it and then use that information to plan and design the next step. As we’re installing low-mobility grout, not only are we constructing that portion, but we’re using that information that’s gathered to plan and design the next step.”
Despite the uncertainty on the front end, TVA workers are still on track to complete the project in 2022, keeping the completion date in line with the original projection made in July of 2015. So far, TVA workers have used low-mobility grout – which is roughly the same consistency as toothpaste – to fill holes in the earthen embankment that were allowing water to escape the reservoir. They added some high-mobility grouting on top of that, which is similar to the thickness of a milkshake, before building berms out of 220,000 pounds of rock to help hold the embankment in place.
All that is left now is to secure a contractor and build a concrete cutoff wall to further reinforce the dam. While the process has been slower than many would like – particularly those who own businesses and land along Boone Lake – Vinson said a methodical approach has been necessary in order to ensure the work stands the test of time.
“We wanted to do it once, and we wanted to do it correctly,” he said. “There could have possibly been some other avenues where we tried something, see if it works and then you may have to come back and do rework in a few years. So we took the approach that we’re going to try to do this once, do it correctly and put in a repair that keeps us from having to come back and adjust.”
As the project enters its fourth year, Vinson said he is certainly well-aware of the criticism the TVA has received for the length of time it has taken to complete the job.
“We’ve had a lot of pressure from the public, and we get what I consider to be information out of context,” he said. “It only took two years to build Boone Dam. Why does it take seven to repair it? And that is true. The construction portion of Boone Dam took two years, or actually 26 months, to build. What people are leaving out of that is that they planned it, they designed it and it took two years to build it. The construction was 1950 to 1952. But the Holston River Power Company started looking at that site and planning in 1936.”
Even when you account for World War II, which put building of Boone Dam on the back burner for several years, Vinson said it took eight years to plan, design and build the dam. As his team pushes ahead, Vinson said the safety of the workers and the quality of their work will continue to be the top priority.
“We’re working really hard,” he said. “We didn’t have the leisure of studying this for 13 years and designing like you would with building a dam.”