Highway 104 near Oxford at low risk for sinkhole: report

The chance of a sinkhole forming around a section of the Trans-Canada Highway near Oxford, N.S., is low, according to a new report that was prompted after a sinkhole formed beside the Oxford Lion's Club in 2018.

Although archival images confirmed that section of Highway 104 was built over a sinkhole, a geotechnical study conducted by Harbourside Geotechnical Consultants found the threat of one is low if the province keeps monitoring for ground movement and takes extra steps to control the water runoff from the highway and its ramps.

In a statement, Nova Scotia Transportation and Infrastructure Renewal Minister Lloyd Hines said the province would be "moving immediately on the recommendations in the report by improving ditching and also by strengthening our monitoring program."

The department said it will also develop a contingency plan to be followed if any sinking is observed near the highway and ramps.

The department said the study, which focused on a 500-metre section of Highway 104 just south of the Town of Oxford, looked at subsurface soil and rock conditions along and beneath the highway west of Exit 6.

While deposits that can dissolve in water such as gypsum are prevalent in the area, the study found the deposits that can result in sinkholes were deep underground.

Rachel Jones, the CAO of the Town of Oxford, only had a chance to look over the study briefly on Thursday, but said it was a long time coming. 

"Having it as perhaps a higher priority than it has been in the past is a good thing. There are and continue to be sinkholes on either side of that stretch of the highway," Jones said.

"The area is prone to it and we generally don't get an awful lot of warning prior to a cover collapse happening. We didn't have any warning with the sinkhole at the Lion's Club property."

Jones said she hasn't observed issues with pooling water on the highway or its ramps, but she said it the province agreeing to monitor it more is a good step forward.

"It's a far cry from a year ago when the statement was that there wasn't anything there. This area is prone to sinkholes and that's not the province's fault, that's just geology," she said.

But Jones said she is concerned about sinkholes. She said Slade Lake near the highway — locally referred to as Dry Lake — completely drained this summer.

"We've not had that type of activity here probably since the 1970s," she said.