A new report says four main causes led to the catastrophic Tennessee Valley Authority (TVA) fly ash spill that dumped a devastating 5.4 million cubic yards—over one billion gallons—of toxic coal sludge into Tennessee’s Emory and Clinch rivers and the 300 acres surrounding the TVA Kingston plant. According to KnoxNews, William Walton, AECOM engineer, and TVA’s Chief Operating Officer, Bill McCullum, recently discussed the report.
In addition to a layer of unstable ash sludge—“slimes”—that went undetected, the “construction of retaining walls on top of the ash,” “saturation of the stored ash,” and “pressure exerted by rising stacks,” led “to this problem,” said Walton, who added that, “It’s almost a perfect storm,” quoted KnoxNews. Walton said the slimes were “comprised of fine particles of fly ash, water, and sediments underneath the ash stacked in one area of the pond,” explained KnoxNews, which noted that Walton compared the consistency to that of yogurt.
It seems TVA engineers who conducted stability analyses on the pond for decades did not detect the six-inch deep slime, said Walton. The AECOM report stated the slimes’ “creep failure” and ash liquefaction triggered the spill, said KnoxNews. KnoxNews also explained that internal wall failures occurring over an hour caused the dike blowout that sent out a 47-foot-high “tsunami of sludge” with ash shooting up over half a mile from the pond’s walls, citing the report. The toxic wave pushed one house from its foundation, destroyed others, annihilated docks, and moved construction equipment, leaving a toxic fiasco in its wake.
According to Walton, the issue began at the Kingston plant when coal combustion waste was carried into a section of Watts Bar Lake; in 1958 a dike was built to create the pond from the reservoir. The ash sluicing created the slimes, he added, reported KnoxNews Since, TVA built “terraced walls” 200 feet from the “exterior dike, on top of the wet ash,” which piled ash, increasing pressure on the base, explained Walton, who noted that heavy December rains and seismic activity were likely not factors in the horrendous spill. Soil scientist, Bryce Payne, said the report confirms his independent analysis in which he concluded that the when TVA stacked the ash, it “doomed” the plant, said KnoxNews. “It was inevitable. There’s no question,” said Payne, who has a background in fly ash and explained it does not shed water when under pressure.
Stephen Smith, executive director of the Southern Alliance for Clean Energy, said the report shows that correct site characterization did not occur when site expansions took place, adding, “The report points to structurally weak slimes in the foundation from historic ash disposal as a significant contributing factor…. One would think that TVA, with its vast engineering experience, would have known to look for this material,” reported KnoxNews.
Attention has since been focused on coal ash facility health hazards and emergency response protocols. A lack of the mandatory emergency response protocols allegedly adversely affected delivery of critical information. According to Roane County’s emergency management director, Howie Rose, key decisions were delayed because of the time it took the TVA to provide meaningful information that caused estimated 12-hour delays over decisions regarding evacuation orders and “health, safety, and environmental concerns,” said KnoxvilleBiz previously.
Last month we wrote that information pointing to “significantly higher cancer risks” for those living near coal-fired power plant ash dumps was allegedly covered up by the recent Bush Administration, citing a report by EnvironmentalIntegrity.org. Apparently, the 2002 EPA Risk Screening Report was only finally released in 2009 after President Barack Obama and his administration took office, said Environmental Integrity.
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