Tłı̨chǫ All Season Road
Designing climate resilient transportation corridors through the Northwest Territories
Peter Kiewit Sons ULC | Government of the Northwest Territories (GNWT)
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Near Yellowknife, Northwest Territories
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2019-2021
The first project in Canada to uphold the highest level of climate resilience through a government cost-sharing mechanism
The design and construction of this new 97 km all-season road was completed approximately one year ahead of schedule
Named a Global Best Project by Engineering News-Record (ENR)
Challenges
- Northern regions are experiencing the effects of climate change at an accelerated rate compared to most southern regions. Infrastructure that relies on properties of permafrost and ice for long-term stability must now be developed on a risk-based approach, with design processes that recognize and rationalize future uncertainty from changing climatic conditions.
- Incorporating climate change and forest fires into the design of roadway and bridges.
- Finding a practical balance between initial cost and performance, given that performance measures may be compromised in unstable permafrost conditions.
Solutions
- Incorporation of a region-specific climate change and forest fire adjustment factor for peak river flow rates into design to achieve climate change resilience.
- Reduction in permafrost disturbance by designing higher than typical roadway embankments in select locations to minimize the cut depths and reduce exposure and susceptibility to increasing climate temperature impacts, as one example.
- Designs that incorporate features to facilitate installation and construction in sub-Arctic temperatures, including frost non-susceptible fills at key structures such as bridge culvert structures.
Highlights
- Named a Global Best Project by Engineering News-Record (ENR) in the road/highway category for the project’s exceptional safety performance, teamwork, and ability to overcome significant challenges.
- Canada’s Top 100 Infrastructure Projects (2020).
- Canadian Council for Public-Private Partnerships (CCPPP) Gold Award (2019).
- The region-specific climate change and forest fire assessment performed on this project is currently being implemented on another GNWT project that Hatch is delivering titled “Hydrological Studies for Flood Mitigation Measures along Highway 1, 3, and 5.”
“This is a major step in improving connectivity for all residents of the Northwest Territories. The Tłı̨chǫ All-Season Road will increase resiliency of the Northwest Territories road network, while allowing for improved social and economic outcomes for the people of Whatì, Gamètì and Wekweètì.”
Project numbers
97 km of new highway4 bridge structures
3 bridge culverts
200+ highway drainage culverts
$200 million total capital cost
$6 million total engineering fees