Canadian engineers build a road to withstand Arctic climate change
Engineers faced a unique challenge building a road from Inuvik to Tuktoyaktuk in the Northwest Territories, because the area is above the treeline on the tundra permafrost. It's snowy and icy in the winter time. The only way between the two towns on land was by ice road. In the summer, the top active layer of the permafrost thaws.
Ed Grozic, a permafrost engineer with Kiggiak - EBA Consulting Ltd, was one of the engineers who was involved in the planning, design, environmental screening, and completion of the highway. He says you can't drive over the tundra during the summer because it becomes a watery landscape. It's too "soft and spongy."
They had to construct the new road during the Arctic winter when the ground was frozen. They sourced local, natural materials to form the fill mostly sand-sized, that was placed on the tundra to support the gravel road. It was made out of gravel because it's more malleable than asphalt as the ground expands and contracts when it freezes and thaws every year.
The road was built thicker than most highways, so as not to disturb the top layers of permafrost that thaws in the summer, "There's only so much the thaw that can physically happen from the ground surface down," says Grozic. "If the road is thick enough, then there isn't enough thaw energy to allow the thaw to advance through the entire fill into the original ground."
This area in the Arctic is melting faster than most. That's expected to continue as our climate warms. Grozic says they did engineering geothermal modelling analysis in the design to make sure the highway and bridges would last well into the future even as the climate warms.