TVA's Kingston Coal Ash Will be Stored Onsite
The U.S. Environmental Protection Agency Region 4 on May 18 approved the Tennessee Valley Authority’s (TVA) selected cleanup plan for the next phase of coal ash removal at the TVA Kingston site in Roane County, Tenn.
The cleanup plan, one of three alternatives proposed to the public earlier this year, requires TVA to permanently store onsite all of the ash being removed from the Swan Pond Embayment, which includes land and waterbodies adjacent to the TVA coal ash disposal area. The embayment area will then be restored to conditions that protect human health and the environment. After careful review of all comments received between January and April, TVA, EPA and the Tennessee Department of Environment and Conservation (TDEC), agreed that the selected cleanup plan provides the best option to protect public health and the environment.
The cleanup plan approved by EPA in a signed Action Memorandum (AM) was chosen above the others because of its protectiveness, ease of implementation and cost effectiveness.
The cleanup plan includes:
Removal and onsite storage. TVA will remove and consolidate approximately 2.5 million cubic yards of ash from the embayment. All the ash will be consolidated onsite in the re-engineered TVA coal ash disposal area, and no material will be taken off-site. The plan virtually eliminates the risks and costs associated with shipping ash over public roads or by rail. Onsite disposal also addresses community concerns about proper disposal and management of ash in off-site landfills.
Building protective perimeter dike. TVA will place dry ash atop an engineered base layer of sand, gravel and geo-fabric. The dry ash will be placed into the disposal area slowly so that it does not slide. The company will install a new dike around the entire perimeter of the coal ash disposal area to keep the ash from entering the embayment in the future. This dike will go 60 to 70 feet below the ground to the shale bedrock and will consist of overlapping soil-cement columns that can withstand a local 6.0 magnitude earthquake. The coal ash area will incorporate measures to divert drainage and control runoff.
Closing the disposal area. Once all the ash has been put in place, a two-foot clay cover and one foot of top soil will be put over it. Vegetation will then be planted to prevent erosion. Upon completion, the structure will be closely monitored and regularly inspected to ensure public health and safety. TVA will conduct long-term groundwater monitoring.
The height of the closed coal ash disposal area will be approximately 25 feet above the road surface, which is about 30 feet lower than the former dredge cell. The ash pond will be closed at the same time as the former dredge cell. Closing the areas simultaneously will eliminate the need for imported fill material to close the ash pond, which is expected to result in schedule efficiencies and cost savings.
Restoration. Following the removal of ash to native sediments, TVA will restore a complex mosaic of forested, scrub-shrub and emergent wetland plant communities that will provide diverse habitats for fish, semi-aquatic amphibians and bird species.
Drinking water, river water and groundwater in the area are sampled on a routine basis, and current results indicate no exceedances of drinking water standards or surface water quality criteria. Continued ecological, groundwater and river sampling will be conducted indefinitely after the cleanup is complete to monitor environmental conditions surrounding the site.
Field work to prepare for the cleanup is expected to begin in late May as the time-critical work on the site concludes. This portion of the cleanup is estimated to take about four years to complete and will cost approximately $268.2 million, which includes an estimated $686,000 in annual maintenance costs for the first 30 years once the cleanup is complete. Ongoing five-year reviews will be conducted to ensure the integrity of the ash containment.
Public comments were sought on the Engineering Evaluation/Cost Analysis (EE/CA) Report and the alternatives described in it to restore the environment. TVA’s responses to all comments received can be found in the responsiveness summary, an appendix to the Action Memorandum. Public comments on the AM itself are being accepted through June 18 and should be submitted via email to email@example.com or in writing to
TVA, P.O. Box 40, Kingston, TN 37763-0400.
A separate EE/CA Report for the residual ash in the river system that remains once the time-critical dredging is complete will be prepared at a later date.