Tennessee subterranean authority member won’t take first Boring Company tunnel ride

A member of the Tennessee board overseeing construction of a Nashville tunnel isn’t worried yet about the potential for sinkholes detailed in a new study, but even he is leery it could be flooded by the Cumberland River.

Former state Sen. Bill Ketron of Murfreesboro, a member of the newly-formed Subterranean Transportation Infrastructure Coordinator Authority, said Monday he’s aware of a report by the Southern Environmental Law Center that the Boring Company’s tunnel from downtown Nashville to the airport could cause sinkholes, groundwater contamination and a litany of problems. He hasn’t spoken with anyone from Elon Musk’s Boring Company about the report and isn’t overly concerned yet about the potential for damage.

Ketron said he toured the section of the tunnel that’s been completed and was told the limestone under Nashville is extremely hard. The company told him concrete for the underground structure is prefabricated in Nevada.

Asked whether he feels the concrete barriers will be able to prevent flooding in the tunnel from the Cumberland River, Ketron quipped, “They say that they will, but I don’t think I want to be one of the first ones riding through it.”

A 9.5-mile tunnel that will ferry passengers in all-electric Tesla vehicles is supposed to be 13 feet in diameter and dug 30 to 60 feet underground to provide transportation between downtown Nashville near the state Capitol and the Nashville International Airport. Republican lawmakers have called the project a good method for reducing traffic on Nashville interstates.

Ketron made the comment as he recalled posing questions to former Nashville Mayor Megan Barry and a consulting firm in 2017 about the potential for massive leaking when her administration proposed a nearly $1 billion tunnel under the downtown area from Music City Central to Fifth and Broad. 

“I raised concerns about (if) you get too close to the Cumberland River you might fill the whole thing with water,” Ketron said.

The project failed to get off the ground as Barry stepped down from office amid scandal and the $5.2 billion transportation plan fizzled.

The Southern Environmental Law Center’s analysis shows the Music City Loop route will be forced to go through layers of bedrock prone to sinkholes and caves, known as karst geology, a threat to cause more sinkholes, groundwater contamination and the settling or sinking of rock. 

The Boring Company has said in an environmental impact assessment it will “avoid tunnel boring in areas where karst development is identified.” 

The Southern Environmental Law Center, though, said in its report that the route won’t be able to avoid karst regions with caves and underground streams in the area because it runs under Browns Creek, Mill Creek and the Cumberland River. 

The Southern Environment Law Center report

The Southern Environmental Law Center report details a “karst mitigation plan” obtained through a public records request describing methods the company would use to find karst features, including drilling wells into rock to see whether it’s solid and testing called “multichannel analysis of surface waves,” which uses vibrations to determine whether underground structures are present.

The report also points toward the possibility of groundwater pollution caused by the disturbance of areas such as the former Aladdin Industries site on Murfreesboro Road near the airport, which has a history of contamination caused by hazardous solvents and metals. 

Democratic state Sen. Heidi Campbell of Nashville said Nashville sits on limestone that’s riddled with caves and sinkholes and pointed out the report by an independent hydrogeologist warns that the tunnel could push toxic materials into the groundwater.

“Instead of demanding answers, the state handed Elon Musk our public right-of-way, cut Nashville out of the decision and took the company’s own paid-for report at its word,” Campbell said in a statement to the Lookout.

She called the state’s actions “reckless” and said taxpayers will wind up paying to fix any sinkhole that opens on Murfreesboro Road.

Tennessee donated the underground right-of-way to the Boring company for its project and set up the subterranean authority to oversee it.

Gov. Bill Lee has said the state gave the right-of-way because the Boring Company is making an “enormous investment” on the state’s behalf.

A Department of Transportation spokesperson did not respond immediately Monday to questions for Commissioner Will Reid.