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WATERSHED DELINEATION IN AREAS OF PERMAFROST DISTURBANCE ON EASTERN BANKS ISLAND, NWT: A GEOMATICS APPROACH FOR PREDICTING WATER QUALITY IMPACTS

Session: Permafrost Degradation II / Dégradation du pergélisol II

Ashley Rudy, Queen's University (Canada)
Scott F. Lamoureux, Queen's University (Canada)
Jean E. Holloway, Queen's University (Canada)
Melissa J. Lafrenière, Queen's University (Canada)
Steve V. Kokelj, Northwest Territories Geological Survey (Canada)
Rebecca Segal, University of Victoria (Canada)
Trevor C. Lantz, University of Victoria (Canada)
Robert H. Fraser, Canadian Centre for Remote Sensing (Canada)
I. Rod Smith, Geological Survey of Canada (Canada)

The goal of this study was to develop a framework for informing water-sampling strategies to evaluate the relationships between thermokarst disturbances and impacts on water quality. A permafrost disturbance inventory for the Johnson Point area, eastern Banks Island was produced through a visual inspection of SPOT 4 and 5 satellite imagery. A total of 197 retrogressive thaw slumps were identified and digitized, ranging in size from 2600 to 885 500 m2 with the majority of slumps located adjacent to lakes and streams. Watersheds were derived from the Canadian CDED DEM and NHN stream network data sets using ArcGIS with Spatial Analyst extensions. Specific criteria were used to create a hierarchy of nested watersheds. This contextual information will enable us to determine if: 1) the relative density of disturbance is related to the intensity of water quality effects; 2) if water quality is impacted more by the areal extent of disturbance or numbers of individual disturbances; and 3) whether the hydrological connectivity and distance of a disturbance to a water body affects downstream water quality. This knowledge will provide information suitable for researchers, communities and decision makers to assess the impact of permafrost disturbance on surface water environments.