Investigation and Quantification of Water Track Networks in Sub-Arctic Alaska

摘要

Water tracks are drainage pathways that route water through the soil over a subsurface, lateral constraining layer such as permafrost. Due to the prevalence of permafrost in the polar environments, water tracks form the dominant drainage network, yetthey remain relatively unexplored. The objective is to investigate water tracks in thickly vegetated boreal regions for a systematic understanding of their interactions with engineered infrastructures. A methodology to map water tracks in subarctic Alaska is being developed to conduct preliminary analysis of their geotechnical impact on infrastructures. The study area is Goldstream Road in Fairbanks, Alaska. This road experienced high amounts of damage, possibly due to interception of prominent water tracks. In 2012, the Alaska Department of Transportation collected geophysical data along the road. We plan to create a water track distribution map around the Goldstream Road using remotely sensed imageries and correlate it with the geophysical data. Thusfar, water tracks were identified in both permafrost and non-permafrost (seasonal-frost) areas of the Goldstream Road. Furthermore, two highly-varying water tracks were characterized. Both characterizations uncovered quite promising insights. One, in aresidential area of Fairbanks, revealed that water tracks not only form due to lateral constraining layer, but can also form along the boundary between two units with contrasting hydraulic properties (e.g., compacted fill and natural soil). The other water track, by the Goldstream Road, suggested that temperature and moisture content are significant parameters of water tracks. The findings from this study emphasize the need for future explorations of water tracks.