River Reaches—Updated Data Analysis and Temporal Trend Evaluations in Biota: 2009-2015, Tennessee Valley Authority, Kingston, Tennessee (By Arcadis)
The U.S. Environmental Protection Agency in Atlanta reported Thursday that monitoring data shows that areas of Watts Bar Reservoir affected by the 2008 ash spill in Kingston have returned to “pre-spill†conditions.
The ash spill occurred at the Tennessee Valley Authority Kingston Fossil Plant. It released 5.4 million cubic yards of coal ash on December 22, 2008.
Environmental data collected from 2009-2015 shows the fish community, benthic macroinvertebrates (bugs), sediment quality, and tree swallow colonies have recovered to baseline conditions that existed before the spill, the EPA said.
The cleanup was accomplished in three phases under the federal Comprehensive Environmental Response, Compensation and Liability Act, or CERCLA, commonly known as Superfund.
The first phase of the cleanup involved the removal of 3.5 million cubic yards of ash from the Emory River to alleviate flooding concerns and to mitigate further transport downstream. Coal ash removed from the river was de-watered and transported by rail for disposal at an approved landfill in Perry County, Alabama.
The remaining ash in the Swan Pond Embayment of Watts Bar Reservoir was removed in Phase 2 of the cleanup. The coal ash removed during this phase was placed in a re-engineered disposal cell on TVA property that was designed to withstand earthquake forces and then closed and capped in place.
The third and final phase consisted of a comprehensive human health and ecological risk assessment of the estimated 500,000 cubic yards of residual ash that was not removed from the Emory and Clinch Rivers during Phase 1 dredging work.
The entire cleanup was completed over a six-year period from 2009-2015, at an estimated cost of $1.134 billion.
In November 2012, a Monitored Natural Recovery, or MNR, plan for the river system was recommended by TVA and approved by EPA and the Tennessee Department of Environment and Conservation, or TDEC. The approved approach relies on natural processes such as mixing, scouring and redeposition, and sedimentation (burial) to reduce the relatively low ecological risks posed by the residual ash and any input from groundwater from the closed and capped in place coal ash, the EPA said.
“MNR proved to be effective in five years, versus the 10- to 15-year time frame predicted by sediment fate and transport modeling,” the EPA said. “Annual monitoring of the river system will continue for up to 30 years to confirm that risks associated with the residual ash remain low and that ash-related concentrations of metals continue to decline with time. Groundwater monitoring and maintenance of the ash disposal cell on-site will also be conducted over the long term in compliance with permit requirements.”
TVA spokesperson Scott Brooks said the public utility finished the effort in the fall of 2015, but the news announced Thursday shows that, despite the presence of coal ash remaining in the Emory River, the ecosystem is not being harmed.
“And certainly there is no, and never was, any impact to drinking water sources in the area,” Brooks said. “TVA is keeping its commitment and continues to invest billions of dollars in the safe storage and handling of coal ash and other coal combustion products.”
TVA has posted the complete Kingston Coal Ash Recovery Project report on its website here.
More information will be added as it becomes available.
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