Geomorphologic feature mapping methodology developed for the Dempster Highway and Inuvik to Tuktoyaktuk Highway corridors

Abstract

Thaw of permafrost and associated ground ice can reduce ground stability, modify terrain, and reconfigure drainage patterns. This, in turn, can affect terrestrial and aquatic ecosystems, and present challenges to northern societies. Permafrost change can have a significant influence on the integrity of ground-based transportation infrastructure, which is critical to northern communities. The geomorphic landscape can indicate ground ice presence and thaw susceptibility. In 2017, the Geological Survey of Canada and the Northwest Territories Geological Survey collaboratively developed a robust methodology to classify and digitize geomorphic features in permafrost terrain using high-resolution imagery. A 10-km wide corridor centred on the Dempster Highway and Inuvik to Tuktoyaktuk Highway was used to develop and test the methodology. The 875-km-long corridor traverses a variety of geological and physiographic terrain types, including glaciated and non-glaciated terrain. Permafrost here is continuous. However, variation in climate, relief, ecology, and disturbance have produced a diverse range of periglacial conditions. We selected five test sections representative of terrain along the study corridor. The main geomorphic categories are mass movement, hydrological, and periglacial. We used high-resolution (0.6 m) satellite imagery to generate stereo pairs for 3D visualization. Geomorphic features were digitized in ArcGIS. We customized Python scripts to populate the attributes for each geomorphic feature. This Open File provides a background on the physical context and physiographic terrain of the study corridor. The report presents the geomorphic feature identification and digitization methodology and summarizes the results from the test section mapping and its limitations.