Constructing a highway on permafrost is not without challenges. And experts say the key to an infrastructure project such as the Arctic economic and security corridor is sustained maintenance.
A warming climate is changing the dynamics for infrastructure projects even though roads built on permafrost have been a northern reality for decades. Researchers and builders are of the consensus that warming ground temperatures are shortening winters and increasing costs concerns that loom large as the federal government eyes the Arctic economic and security corridor for potential fast-tracking.
The 900-kilometre all-season utility corridor would stretch from Yellowknife to Grays Bay, Nunavut, the site of a proposed deep-water port. That would handle navy vessels as well as large cargo ships capable of loading and transporting materials from future critical mineral mines in both the Northwest Territories and Nunavut.
Since 2000, the temperature of permafrost in some parts of the Arctic has increased up to 1.2 C per decade, according to the Canada’s Changing Climate report released in 2019.
Guy Doré, an emeritus professor at Université Laval’s civil engineering department, has studied the effects of thawing permafrost on transport infrastructure for 40 years.
“If you can actually modify the corridor to avoid the problem, that’s the best solution,” he said.
As permafrost thaws, Doré says that leaves some communities with distorted roads.
That’s what Russell Newmark is seeing along the Inuvik-Tuktoyaktuk Highway in the N.W.T. He’s the CEO of EGT Northwind Ltd., which was contracted to build the highway.
“Because of the heat your road is attracting, you get slumping on the sides,“ he said. “They weren’t being lifted again to be back to the height that they should have been. And so you start getting potholes and you start getting more snow in the centre of the roads,” he said.
There are ways to build a road to limit permafrost thaw, said Jim Stevens, who was part of the planning for the Inuvik-Tuktoyaktuk Highway at the N.W.T.’s Infrastructure department. He now serves as a senior advisor at the West Kitikmeot Resources Corp., which is the proponent for the Nunavut side of the Arctic economic and security corridor.
“The first rule of constructing in that kind of region is you never cut into the surface. Because where you scour or scrape the surface, that’ll accelerate the rate of permafrost degradation,” he said.
Instead, Stevens said it’s about layering material, such as gravel and synthetic fibres, on top of the permafrost to provide some insulation.
For years, Doré and a team of researchers tested different permafrost preservation techniques along the Alaska Highway, including near Beaver Creek, Yukon.
They included installing culvert pipes on the shoulder of the road, or using light-coloured or permeable material on a road’s surface.
“You’ll cool your ground by a few degrees in the winter and the colder ground will resist thawing the next summer,” he said.
Those mitigation measures aren’t perfect though, and that means some road repairs are to be expected.
“The typical [repair] cycle if you’re in an ice-rich environment is typically about three to four years, while if you’re in other areas where there’s no sensitive soil, no ice-rich permafrost, it’s more like 12 to 15 years,” Doré said.
Newmark says the Inuvik-Tuktoyaktuk Highway had suffered from a lack of maintenance for a number of years, and much of the money spent was mostly for clearing snow off the road.
In written responses to CBC News, the N.W.T. Infrastructure department says it allocated $2.2 million each year for maintenance on that highway between 2019 and 2024, and that figure was bumped up to $2.5 million until 2027.
The department says that does include funding for maintenance like gravel surfacing and embankment slope repair.
In 2023, the federal and territorial governments also pledged $14m for the rehabilitation of the highway.
