The Yukon Government manages thousands of kilometres of hard-surface and gravel-surface roadways, as well as bridges, structural culverts, and drainage culverts. Much of this infrastructure was built between 1945-1980. With this aging infrastructure, the Yukon Government has embarked on a program to complete functional plans for all of their major highway infrastructure, with the goal of maintaining the transportation network’s mobility, safety, and reliability. The plans will help the Government to develop a comprehensive understanding of the issues, needs, and budgets for improvements, and to prioritize projects in its annual capital budgets.
The Yukon Government retained Associated Engineering to provide functional planning services for one airport and seven highway corridors totalling 1,400 kilometres. Matthew Bowen, Manager of Resource Infrastructure in our Vancouver office, tells us, “One of these assignments was the Yukon portion (km 0 to km 465) of the Dempster Highway. The objective of the Dempster Highway functional plan was to consider climate change, permafrost, geohazards, and transportation planning to develop a climate-resilient maintenance and improvement strategy that will guide investments along the Dempster Highway corridor over a 20-year planning horizon.”
The Dempster Highway was constructed between 1960 and 1978. The highway is a very remote, gravel road and provides the only year-round highway connection between Inuvik and the rest of Canada’s highway network. Although there are no communities along the Yukon section of the highway, it is a critically important route to the Beaufort Delta Region in the Northwest Territories, serving as a long-haul transport route for food, fuel, supplies, and other goods.
The highway crosses five distinct ecoregions, and contains approximately 1,200 culverts and five bridges. Long stretches of the highway are constructed through floodplains, in zones of discontinuous and continuous permafrost, and within mountainous terrain. The remote location and length of the highway, coupled with the challenging terrain and ground conditions result in relatively high maintenance costs, considering the low traffic volumes (63 vehicles per day).
Over the past decade there has been an increase in the frequency and severity of issues related to drainage, erosion, and permafrost degradation. As the climate continues to warm, rising flow rates and increasing number of extreme weather events will put additional strain on the aging drainage system. With much of the highway located in discontinuous to continuous permafrost zones, the warming climate also has a direct impact on the performance of the road, and can result in settlement, sinkhole formation, embankment failure, and other geohazards. Additionally, there are limited sources of suitable construction aggregate for surfacing material and rip rap for erosion and embankment protection throughout the corridor.
Researchers from Yukon College, the Yukon Government, and various stakeholders contributed to the project’s success. Researchers from Yukon College helped to identify climate and geohazard vulnerabilities. Our staff, Yukon College, Yukon Government, and various stakeholders participated in a workshop to identify issues, priorities, and potential investigations that could be completed to support the functional plan and future projects along the highway.
Key personnel included Matthew Bowen, Ray Korpela, Daniel Letient, Brian de Jong, Jason Kindrachuk, and Ana Varhaug.