BOONE LAKE (WJHL) – The Tennessee Valley Authority is closely monitoring a second area of water moving underground near Boone Dam.
That’s according to a newly released report on the plan to stop a separate area of water movement under and through Boone Dam, something the utility says would have jeopardized the safety of communities downstream if unaddressed.
A year ago, TVA rapidly dropped the level of Boone Dam after discovering a sinkhole and water seeping out of an embankment near the base of the dam.
This past summer, TVA announced its plan to spend 5 to 7 years and as much as $300 million on the repair.
“What we believe is that this proposed repair project that we have laid out for Boone Dam will take care of all of this issue,” said Jim Hopson, TVA spokesman.
At the July 30th meeting in Johnson City, TVA also said the movement of water around Boone Dam was more complex than first thought, and it would require on-going monitoring and possible future remediation.
In its draft environmental assessment of the Boone Dam repair project release last week, TVA released more details about a “potential problem” involving a second area of water movement underground near Boone Dam.WEB EXTRA: TVA Boone Dam Draft EA – October 28 (.pdf)
TVA says its inspection of Boone Dam found water moving underground in the dam’s right rim, the ridge to the east of the dam.
According to the report, “Seepage from the right abutment area is recognized as a potential problem for the long-term performance of Boone Dam. However, more study is needed to characterize the problem, identify possible mitigations, and evaluate options.”
Here’s the full quote from the report:
TVA is also considering taking action to address seepage of the right rim at the dam site. Datafrom instrumentation installed at the dam site have shown that groundwater flows under the dam embankment originate in the ridge to the east of the dam (in the right abutment or right rimof the project). Seepage from the right abutment area is recognized as a potential problem forthe long-term performance of Boone Dam. However, more study is needed to characterize theproblem, identify possible mitigations, and evaluate options. Many of the instruments needed tobetter understand the nature and areal extents of the problem were installed only recently. TVAwill determine at a later date how to proceed to address this seepage, and will conductadditional environmental review if necessary.
“We just happen to be able to find the right rim water movement because of the extensive sensor network that was put in place to detect the cause of the seepage under the earthen embankment.” Hopson said.
Hopson said the second area of water movement would not impact the Boone Dam repair project or the plan to return lake levels to normal in 5 to 7 years.
“If we correct that issue, that allows us to return Boone Reservoir to its normal operating levels. There may be additional remediation in other parts of the Boone reservoir system that we have to be looking at. But our primary concern right now is to ensure the stability of that embankment and by making the repairs return the reservoir to its normal levels,” Hopson said.
“It’s just something we’ve got to look into further to determine if there are additional steps that need to be taken below the dam independent of the earthen embankment that we’re going to be
repairing to restore the reservoir.”The draft environmental assessment will be the focus of a public hearing at Daniel Boone High School Thursday from 5:30 to 7:30 pm.
“We’re going to have to continue looking at that right rim water seepage issue to determine if there is any potential downstream considerations that we have to be aware of,” he said.