Combining AirSWOT with Direct and Isotope Hydrological Measurements for Landscape Scale Assessment of Mackenzie Region Thermokarst Lakes

Evan Wilcox, Wilfrid Laurier University, wilc0150@mylaurier.ca (Presenter)
Philip Marsh, Wilfrid Laurier University, pmarsh@wlu.ca
Branden Walker, Wilfrid Laurier University, bwalker@wlu.ca
Gabriel Hould - Gosselin, Université de Montréal, ghgosselin@gmail.com
Brent Wolfe, Wilfrid Laurier University, bwolfe@wlu.ca

Thousands of small thermokarst lakes cover up to 50% of the landscape across the forest – tundra transition zone between Inuvik and Tuktoyaktuk in the western arctic of Canada. The yearly water balance of these lakes has not been quantified before, nor has the variability in water balance across the region been assessed. Water flux to the atmosphere, permafrost degradation, and limnological conditions are all affected by the lake hydrology, and climate change induced temperature increases and changes to precipitation patterns could affect lake water balances in this region. This necessitates an evaluation of current lake water balance conditions, and an assessment of landscape variability of water balance, in order to predict how the landscape will change in the future. To characterize the water balance of these lakes, direct measurements of lake level, lake discharge, evaporation, basin snow storage, and precipitation were made at two adjacent lakes near the Trail Valley Creek Research Station, 45km N of Inuvik. Each lakes had similar sized catchments, but one lake has a surface area twelve times larger than the other. This larger lake fell below its sill level shortly after snow melt and was only fully recharged by large rainfall events, while the smaller lake was maintained to sill level by runoff the entire year. This lead to the hypothesis that the water balance of a lake can be approximated by dividing the area of its catchment by the area of the lake. To test whether this variable is the dominant control on lake water balance, water levels changes between the two AirSWOT flights in the region are compared to the lake size and its basin size. Stable water isotopes will be sampled from a variety of lakes in the region next year pre-snowmelt, post-snowmelt, and at the end of the summer to describe freeze-up, snowmelt recharge, and rainfall recharge, respectively. This will help describe landscape scale variability while relating results back to the dominant hydrological processes observed from the direct measurements of water balance.

Associated Project(s): 

• Marsh-01

Poster Location ID: 102

Session Assigned: Permafrost and Hydrology