So long, bumpy highways? N.W.T. gov't thinks it may have a solution

If you've ever driven on highways in the Northwest Territories, you'll know that bumps and dips are a way of life — but the territorial government says they may have found a solution, following four years of testing.

Territorial government has been testing methods on four stretches of Highway 3 since 2012

A driver heads over a bumpy stretch of Highway 3, between Yellowknife and Behchoko. The territorial government has been testing methods of reducing bumps and dips in the road - caused by melting permafrost - since 2012 (Chantal Dubuc/CBC)

If you've ever driven on highways in the Northwest Territories, you'll know that bumps and dips are a way of life — but the territorial government says they may have found a solution.

Over the past four years, the Government of the Northwest Territories has been testing sections of road on Highway 3 between Behchoko and Yellowknife, using numerous methods in an attempt to combat abnormalities on highways caused each year by melting permafrost.

"All of them are performing as our scientists predicted," said Kevin McLeod, the director of highway and marine services for the territory, "and there's one that's performing better than we wanted. And that's the one that we will be using into the future."

The successful combination, McLeod said, was a mixture of larger rocks in embankments — allowing cold air to more easily penetrate through — geogrid, a geosynthetic material that's used to reinforce soils, and cellular concrete, which combines to protect permafrost beneath the surface.

"It reacted in a couple ways," said McLeod. "It protected the permafrost more, so that any melting... the permafrost was less affected. It didn't melt as much as it did if it wouldn't have this technique. 

"And secondly, it melted at a slower pace, so if any bumps did appear, they were less severe."

A costly proposition

Though drivers across the territory will be excited at the prospect of less bumpy highways, McLeod said repairs will be slow-going, largely due to cost. The test sections cost between $250,000 and $450,000 each. 

McLeod says the territory currently spends between $4,000 and $20,000 per kilometre to maintain highways, with slightly more on Highway 3, due to a higher volume of repairs. 

"It's a very difficult situation, in terms of engineering," he said. "There is discontinuous permafrost. We've been working on the road, we paved it in 2006, and the road has been windy and twisty since the early '50s. And we are attacking the areas that we can address each year."

McLeod didn't want to put a dollar figure as to what it would cost to begin working on problem areas, but said his division would begin addressing "high priority areas" as soon as they get money from the government.

"Next year, we'll start," he said. "We'll be addressing the more high priority areas with these techniques.

"The areas that are in need of repair — the dipping areas, the areas that are under risk from melting permafrost... we will dig those out, and we'll replace those with these successful methods."

with files from Sonja Koenig


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