Monitoring of permafrost beneath a stream crossing along the Inuvik-Tuktoyaktuk Highway

ABSTRACT: With over 40% of Canada’s landmass situated in regions of continuous permafrost, climate change and its effects pose a major concern for northern regions. Warming air temperatures, one driver of permafrost degradation, can lead to geohazards such as slope instability, soil subsidence, and ground movement, all of which increase the risk of infrastructure failure. The Inuvik-Tuktoyaktuk Highway (ITH) in the Northwest Territories was opened for use in 2017 as the only year-round transportation link to the Arctic Coast in Canada. Since its opening, significant maintenance has been required to keep the road operational as a result of changes in the underlying permafrost. At kilometer 131 of the ITH, approximately 14km South of Tuktoyaktuk, the highway crosses Gunghi Creek. The crossing was originally outfitted with a corrugated steel pipe (CSP) culvert, but following significant deformation the crossing was rebuilt in early 2021 with an open bottom arch concrete structure, founded on 20 adfreeze piles. A ground temperature monitoring program was implemented as part of the rebuild to monitor the performance of the new structure. This has consisted of thermistor strings deployed within the piles, along the road centreline, within the embankment, and other areas of interest. Additional climate data is being collected including temperature, wind, precipitation, and snow depth to assist in numerical modelling to help predict future performance of the structure and others like it.