Johnson City Press – by Tony Casey
A chink in the Boone Dam’s armor has Tennessee Valley Authority officials starting the annual depth drawdown of Boone Lake about five weeks ahead of schedule.
When an Oct. 20 inspection of the dam revealed a sink hole — a common occurrence — TVA workers repaired it quickly. Six days later, an uncommon occurrence happened when seepage was found near the location of the sink hole at the base of the dam.
John McCormick, TVA vice president of river operations, assures the dam is structurally sound, but said the TVA is “exercising an abundance of caution.”
Over the course of the next 11 days, McCormick said the TVA will be bringing down the water level about 11 more feet to the necessary mark of 1,362 feet, which is what he calls the “winter pool” level. The rate at which the TVA can drop the lake maxes out at 2 feet per day and 7 feet for the week.
“We recognize this is an inconvenience,” he said. “We’re asking for patience from the community until we can fix it and fix it right.”
An early drawdown will mean that many on the lake will have to remove their boats and docks more than a month sooner than usual. McCormick said he hopes no one’s jet skis or boats become stranded.
“Property and marina owners with docks and boats need to take necessary precautions for the early drawdown,” the TVA said.
With the water level at the lower level, TVA’s engineers and experts can investigate the cause of the seepage and correct the issue. Currently, the site of the seepage is being marked by a steel bar that is sticking out of the water about 25 yards below the dam.
Jennifer Dodd, a dam safety officer with the TVA — the nation’s largest public power provider and a corporation of the U.S. government — said it could turn out that the cause of the sink hole and seepage is a broken pipe or drain, but they won’t know until the water’s low enough to further inspect. She said the area of the seepage is underwater in the rip-rap rocks near the shoreline.
Volatile weather, unless something near catastrophic, shouldn’t shake the TVA’s duty of lowering the lake before Nov. 10, McCormick said.
“Unless it’s a huge storm, we can do what we need to do,” he said.
A similar situation occurred in 2007 at Bear Creek in Alabama, where seepage was found, but it was dealt with swiftly.
McCormick said this issue won’t result in rate increases and emergency repair costs like this are built into his budget. For the time being, his main concern is public cooperation in dropping the water so the issue can be resolved in a timely and safe manner.
“Public safety is our top priority and we are continuously monitoring the dam to ensure it is safe,” he said. “The accelerated drawdown it out of an abundance of caution. Our engineers want to be sure we understand what caused the sink hole and where the water and sediment is coming from.”
Anyone who wants more information on the TVA’s river system and reservoirs can go on their site at www.tva.com/river.
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Read more: Seepage at bottom of dam causes early lowering of Boone Lake – PHOTOS | Johnson City Press http://www.johnsoncitypress.com/article/121661/seepage-at-bottom-of-dam-causes-early-lowering-of-boone-lake-photos#ixzz3HolHg5nA
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