5. Determining Groundwater Inputs into High Arctic Lakes (Cape Bounty, Melville Island, NU)

Abstract

The focus of this research project is to determine the presence of groundwater seepage within two High Arctic lakes located in continuous permafrost on Melville Island, NU. Small isolated depressions were located at the bottom of each lake using bathymetric data – 21 in East and West Lake (unofficial names) combined. It was hypothesized that these depressions could be the sites of groundwater seepage into the lakes, and these locations then served as sample sites for CTD cast and water sample collection during the 2016 field season. Water chemistry and physical property data were used as indicators of groundwater seepage, as ground water would have properties similar to the source of the ground water, generating a change in water chemistry at each of these sites.
 Ionic analysis has showed site specific change at the bottom of both lakes, related to the underlying bedrock structure. Ionic ratios for the northern sites differ from ratios of the rest of the sample sites, as well as the ambient water of each lake. This correlates with the meeting of two geologic units within both lake limits. Physical characteristic data showed no change within East Lake and a localized change within West Lake, represented as an increase in electrical conductivity and decrease in dissolved oxygen. These results suggest that highly localized groundwater seepage is likely occurring in these High Arctic lakes, and that water property influences to ground water may be even more highly localized.