Estimation of Maximum Lake Depth from the Surrounding Topography; towards a Regional Assessment of the Occurrence of Taliks below Arctic Lakes

Presenter:

 

Anne-Marie LeBlanc – anne-marie.leblanc@canada.ca

 
 

Authors:

 
A-M. LeBlanc – Geological Survey of Canada, Ottawa, ON, Canada
J. Chartrand – Geological Survey of Canada, Ottawa, ON, Canada
S.L. Smith – Geological Survey of Canada, Ottawa, ON, Canada
 

Summary:

Open taliks, areas of unfrozen ground, are mainly found beneath large and deep lakes that do not freeze to their bottom. Their connection to the regional groundwater can affect the development of mine projects due to these potential pathways for contaminant transport. Potential for taliks can be obtained by a first-order estimate by knowing the maximum lake depth of large lakes. For regions formed by glacial processes, maximum lake depth may be estimated with topographic variables from the surrounding landscape. This study explores the use of a high-resolution ArcticDEM to extract topographical variables surrounding lakes in Nunavut to run predictive models of maximum lake depth. Lakes from the Kivalliq (areas of Rankin Inlet and Baker Lake) and the Kitikmeot regions with known maximum depth (n=280) are used to assess maximum depth for all lakes in the regional surrounding of the lakes with known bathymetry. Preliminary results, for the area of Rankin inlet, indicate that for the simplest and best model, lake area and median slope explained 79% of the variance in maximum lake depth. Lakes from Baker Lake and the Kitikmeot region were utilized to further validate the initial model and to identify any local to regional model differences.

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