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TitleLake shoreline evolution and permafrost-related drivers, Rankin Inlet, Nunavut
AuthorLeBlanc, A -M; Bellehumeur-Génier, O; Oldenborger, G; Short, N
SourceArcticNet 2018 Annual Scientific Meeting, proceedings/ArcticNet 2018 Réunion scientifique annuelle, proceedings; 2018 p. 114 (Open Access)
LinksOnline - En ligne (complete volume - volume complet, PDF, 2.35 MB)
Alt SeriesNatural Resources Canada, Contribution Series 20190208
MeetingASM2018 - ArcticNet 2018 Annual Scientific Meeting; Ottawa, ON; CA; December 10-14, 2018
Mediaon-line; digital
File formatpdf
AreaKivalliq; Rankin Inlet; Hudson Bay
Lat/Long WENS -92.3508 -92.1539 62.9206 62.8761
Subjectshydrogeology; surficial geology/geomorphology; environmental geology; geophysics; Nature and Environment; Science and Technology; permafrost; ground ice; periglacial features; ice wedges; surface waters; lakes; shoreline changes; water levels; climate effects; remote sensing; satellite imagery; airphoto interpretation; hydrologic environment; snow; precipitation; glacial deposits; tills; marine sediments; topography; displacement; Radarsat-2; ALOS-2; climate change; permafrost thaw; infrastructures; Indigenous culture; Indigenous lands; traditional knowledge; glaciofluvial sediments; lake area; active layer thickness
ProgramClimate Change Geoscience, Permafrost
Released2018 12 01
AbstractThe western coast of Hudson Bay in the Kivalliq Region of Nunavut is rich in natural resources and has potential for resource development. In addition, the establishment of a transportation and transmission corridor between Manitoba and the Kivalliq region has been under consideration for several years. Knowledge of permafrost conditions and processes is required to understand climate change impacts and to aid in developing adaptation solutions. However, the scarcity of permafrost data along the western coast of Hudson Bay hinders understanding of historical and contemporary permafrost conditions and sensitivity to climate warming. Local and traditional knowledge on permafrost and landscape change was gathered at a participatory mapping workshop in Rankin Inlet in 2016 to improve regional characterization of permafrost conditions. Among various observations, the most recurrent was of decreasing lake water levels. Analysis of historical air photos and satellite imagery was completed for 215 lakes near Rankin Inlet, and validated by field observations. The objective was to determine if permafrost-related drivers could explain the observed lake level changes after accounting for fluctuations in lake area caused by variations in the hydrological cycle, inferred by historical snow and precipitation conditions. Analysis results indicated that lakes in the study area were either expanding, draining, or remaining stable. Draining lakes were easier to identify than expanding lakes, which were only perceptible by subtle local changes in shoreline morphology. This might explain why local knowledge holders have preferentially reported low lake water levels in recent years. The distribution of lake expansion and drainage was influenced by surficial geology. A disproportionately high number of observations of lake expansion occurred in undifferentiated till and marine sediments. Draining lakes were more commonly found in glaciofluvial sediments, especially in areas of high topographic relief. Seasonal and inter-annual ground surface displacement measured with Radarsat-2 and ALOS-2, respectively, were used to validate areas of change near lake shorelines. Though translation of these remotely-sensed datasets to real displacement measurements is not straightforward, general relations were nonetheless established between the displacements and locations of stable, expanding, and draining lakes. These relations support (1) the thaw of ice-rich layers near the top of permafrost where localised lake expansion is observed, and (2) increased lake storage resulting from active layer thickening in coarse sediments. We also hypothesize that ice-wedge degradation is involved in lake water level changes. The results of this study contribute to a better understanding of the relation between permafrost and surficial geology, and how these terrain units could respond to a warming climate.
Summary(Plain Language Summary, not published)
The Geological Survey of Canada undertaken a study to determine if permafrost thawing could explain an observation, made by the local people, of lake level change near the community of Rankin Inlet, Nunavut. Knowledge of permafrost conditions is required to understand climate change impacts and to aid in developing adaptation solutions. Results indicated that some of the lake level change were due to permafrost thawing, triggered by climate change, while others responded to annual precipitation change. When permafrost thawing was involved, lake water level change was influenced by surficial geology units. This association between lake level change, permafrost, and surficial geology units is used to extrapolate permafrost conditions over a regional scale and assess how these terrain units could respond to warming climate.