The Public Infrastructure Engineering Vulnerability Committee (PIEVC) has developed a standardized protocol to assess the vulnerability of Canada’s public infrastructure to climate change. Case studies have been carried out to date across Canada, testing and calibrating this protocol on various infrastructures. This report presents the results of the case study undertaken for a 100 km section of Northwest Territories’ Highway 3 located between Behchoko (Rae-Edzo) and Yellowknife (km 240 to km 333). The principal objective of this vulnerability assessment is to quantify how climate change may impact the highway.

This section of the highway is located in an area with warm and discontinuous permafrost, where permafrost temperatures are generally warmer than -1°C, permafrost is not found everywhere and ground ice contents vary significantly. The highway was originally constructed as a gravel road in 1968. Between 1999 and 2006, the alignment for this section of highway was straightened and reconstructed, and the road surface chip-sealed. To date, this section of highway has experienced significant sagging in soil-covered areas and requires considerable maintenance efforts to keep the road in a comfortable and safe driving condition. The embankment deformations have been attributed to the degradation of the ice rich permafrost foundation.