Sinkhole develops under dam in US — 7 nuclear reactors downstream

 

TVA makes aerial inspections by helicopter and ground inspections of its transmission lines and surrounding areas twice a year to insure that the system remains safe and reliable. View of TVA Boone Dam located near TN State Highway 75. (Lee Talbert/Johnson City Press)

View of TVA Boone Dam located near TN State Highway 75. (Lee Talbert/Johnson)

 

Sinkhole develops under dam in US — 7 nuclear reactors downstream

Water now seeping out — Gov’t notified of ‘stability issues’, plants begin evaluating potential flood impacts — Official: An ‘uncommon’ occurrence, we’re monitoring it continuously and working around clock — Structure same height as Niagara Falls

By ENENews

Johnson City Press, Oct. 30, 2014 (emphasis added): Oct. 20 inspection of [Tennessee’s Boone] dam revealed a sink hole… Six days later, an uncommon occurrence happened whenseepage was found near the location of the sink hole at the base of the dam

NRC, Oct. 30, 2014: … BOONE DAM STABILITY ISSUES… “TVA conducted a briefing for government officials… after discovery of a sink hole near the base… water and sediment [has been] found seeping from the river below the dam. TVA is continuously monitoring the dam… The dam is located upstream of all three TVA nuclear sites… The NRC Senior Resident Inspector was notified. The licensee is evaluating this event for potential impact on the design basis flooding level.”TN_Dam_Nuclear

Times Free Press, Oct. 30, 2014: Tennessee Valley Authority engineers [will] search for the source of water seepage… Water and sediment were found Sunday seeping from the river bank below the dam.

TVA, Oct. 30, 2014: A sink hole was discovered near the base… water and sediment was found seeping from the river bank below the dam…

John McCormick, VP at TVA: [We’re] exercising an abundance of caution… Unless it’s a huge storm, we can do what we need… we are continuously monitoring the dam… engineers want to be sure we understand what caused the sink hole and where the water and sediment is coming from.

WCYB, Oct. 30, 2014: [A] sinkhole and seepage of clay particulates into the water at Boone dam… [is near] the bottom of structure on the river side of the dam… TVA employees are working around the clock to find the cause of the sinkhole and the source of the seepage. “The seepage into the waterway is not a common occurrence,” said McCormick… they do not have a definite timetable for finding the source of the seepage…

Boone Dam is just over the border from Virginia, where a powerful M5.9 quake struck in 2011Times Free Press: TVA inspects dams, nuclear plants after earthquake [and] is in the process of performing visual walk downs and inspections at… Boone

USGS: [Quakes] in the eastern U.S. can travel much farther and cause damage over larger areas than previously thought [and] damaging effects can extend over a much larger area… the farthest landslide from the 2011 Virginia earthquake was 245 km from the epicenter. This is by far the greatest landslide distance recorded from any other earthquake of similar magnitude… [This quake] occurred in an area 20 times larger than expected [and] landslide distances… are remarkable… [it’s] the largest distance limit ever recorded…

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Top Official: “Sinkhole has sunk further… we have water coming through dam” upstream of nuclear plants

“Now agency’s top priority”; “Continued flow…could destabilize dam” — Section caved in at base — Gov’t not disclosing inundation maps over security concerns; Private meeting with facility in path (VIDEO)

By ENENews

WJHL, Apr 28, 2015 (emphasis added): [T]he head of the nation’s largest public utility… TVA President Bill Johnson toured Boone Dam [and] said water was moving through the base of the earth filled portion of the dam carrying sediment… “we do have water coming through the dam because the sinkhole has sunk further,” Johnson said pointing to a section of caved-inparking lot at the base of Boone Dam… Johnson said it is essential for TVA to figure out how to stop the flow of water through the base… because continued flowsinkhole_photo of sediment-laden lake water could destabilize the dam.

Johnson City Press, Apr 28, 2015: TVA leader: Boone Dam is top priority

Kingsport Times News, Apr 29, 2015: TVA already has spent millions of dollars looking for the fix and is likely to spend millions more, Johnson said, adding cost is not a factor… The seepage is being blamed on karst, a geological characteristic [that] occurs with dissolution of bedrock, such as limestone. The more rock lost, the more room for more water to flow through – speeding the further dissolution of rock. Seepage through an earthen section of a dam [with]sediment… can indicate ongoing erosion.TN_nuclear

Bristol Herald Courier, Apr 28, 2015: [TVA officials]continue to report sediment seepage in the earthen part of the dam… Travis Brickey, TVA senior program manager, said via phone that repair is still in the “discovery stage”… but there is sediment seepage in the earthen part of the dambecause water has, over time, found its way through karst underground.

Kingsport Times News, Apr 6, 2015: In February… TVA officials met privately with Mayor Dennis Phillips and [an official] at Eastman Chemical Co. – to discuss the seepage… “TVA’s intent is to protect everything downstream“… Phillips said. “They didn’t get into any specifics on houses or areas involved. It’s just naturally understood that if something happened to the dam, it would be a major problem“… Phillips said he is very supportive of Boone Lake remaining at its current level or lower until TVA determines there is no chance of disaster. City Manager Jeff Fleming said… “we have to support [TVA’s decision], rather thanrisk something catastrophic happening“… Last month, the Times-News submitted a [FOIA] request… asking for inundation maps [for] areas downstream… “We are unable to publicly disclose the inundation maps, studies and plans… due to security concerns,” said TVA FOIA Officer… “There were no assurances… It could be multiple years” [Phillips said].

WJHL transcript, Apr 28, 2015 — Bill Johnson, TVA president: “You see here the sinkhole in the parking lot”… He said [it] is now the agency’s top priority… Sediment seeping downstream led TVA to drastically drop water levels — now we know to keep people downstream safe.