‘Special Alert’ issued for major dam upstream of US nuclear plants — Muddy seepage coming up near foundation — Cause of sinkhole and ‘mysterious’ discharges unknown after weeks of analysis — Newspaper: “Hopefully, it isn’t catastrophic” — Officials working around clock, submarines and ground-penetrating radar in use
Published: November 24th, 2014 at 2:44 pm ET
Follow up to: Sinkhole develops under dam in US with nuclear plants downstream — Water now seeping out — Gov’t notified of ‘stability issues’, plants begin evaluating potential flood impacts
Tennessee Valley Authority, Nov 17, 2014 (emphasis added): Special Alert – TVA will continue to lower Boone Lake… to help engineers determine the cause of water and sediment seeping from the riverbank below the dam. The safety of our employees and the public is TVA’s top priority… we are continuously monitoring the dam.
TVA, Nov 12, 2014: “Public safety is our overriding priority and we believe that continuing the drawdown is a prudent action we should take” [said John McCormick, TVA River Operations]. Over the past couple of weeks TVA engineers and independent engineering firms have [used] side-scan sonar, remotely controlled submarines and ground-penetrating radar.
WCYB, Nov. 13, 2014: Engineers have still not found the source of water and sediment [in the] investigation into a sinkhole and seepage of clay particulates… at Boone Dam… They are working around the clock to find the cause.
WJHL, Nov 20, 2014: TVA: still no cause known for Boone Lake seepage — The cause of a mysterious problem on the banks of Boone Lake still has not been found.
Hydroworld, Nov 5, 2014: Seepage at TVA facility prompts dam safety inspection… During dam inspection Oct. 20, engineers… became aware of a sinkhole… Oct. 26, inspectors discovered seepage near the location of the original sinkhole, underwater in the… foundation.
Times-News, Nov 7, 2014: Muddy seepage [at] Boone… Hopefully, it isn’t catastrophic.
WJHL, Nov. 12, 2014: After weeks of investigation, [TVA] still doesn’t know what’s causing water and sediment to seep from the Riverbank below Boone Dam [or] whether the seepage is related to a nearby sinkhole… TVA is warning dock and marina owners that the water is going down yet again… officials seemed confident it would find a solution to the problem… But now, two weeks later, TVA still doesn’t know… Typically, TVA keeps a regimented schedule… But Wednesday’s announcement is open-ended. TVA only said the duration of the extended drawdown depends on the results of its investigation.
WJHL transcript, Nov 12, 2014: Warning for people who live and work around Boone Lake… levels will drop faster and lower than normal… to solve a lingering mystery [and it] will keep dropping until crews find out what’s going on. — John McCormick, TVA official: “The sinkhole by itself is not uncommon, but the seepage into the waterway is not a common occurrence.”
Watts Bar Nuclear Plant, 2.4 Hydrologic Engineering (1 of 2), Aug 14, 2013: Dam Failure Permutations – There are 12 major dams above Watts Bar Nuclear Plant whose failure could influence plant site flood levels [including] Boone… failure of low margin dams is postulated during the [probable maximum flood] for the Boone, Fort Patrick Henry, Melton Hill and Apalachia Dams… The failures are complete and instantaneous down to original ground elevation… Watts Bar West Saddle Dike… is postulated to fail when its peak headwater elevation occurs [and is] assumed to be complete and instantaneous down to original ground.