Controls on Thermokarst Lake Water Balances in the Inuvik - Tuktoyaktuk Region

• Main Author: Wilcox, Evan J.
• Format: Text
• Language: English
• Published: Scholars Commons @ Laurier 2023
• Subjects: permafrost; lakes; hydrology; water balance; water isotopes; arctic; Soil Science; Arctic; Canada; High Lake; Inuvik; Level Lake; Northwest Territories; Rapid Lake; Tuktoyaktuk; Climate change; Ice; Thermokarst
• Online Access: https://scholars.wlu.ca/etd/2547; https://scholars.wlu.ca/cgi/viewcontent.cgi?article=3695&context=etd

There are tens of thousands of thermokarst lakes in the Inuvik-Tuktoyaktuk region, located in the northwest corner of the Northwest Territories, Canada. These lakes formed following the last glacial period in areas where ice-rich permafrost thawed and created depressions in the landscape. The Inuvik-Tuktoyaktuk region is one of the fastest warming regions in the world, leading to changing precipitation patterns, permafrost thaw and deciduous shrub expansion, all of which are affecting the water balance of thermokarst lakes. During the past several decades, lake expansion and contraction have been observed in response to fluctuations in precipitation. While these changes in lake surface area and number have been documented, less is known about how varying meteorological conditions, lake and landscape features, and hydrological processes have regulated these changes in thermokarst lake water balances. Many studies documenting fluctuations in lake surface area often observe some lakes expanding in area while others contract during the same period of time, suggesting that lake and watershed properties regulate how lakes react to climate change. Rapid lake drainage, which can be initiated by extremely high lake levels, is occurring at an increasing rate. The main objective of this thesis is to quantify the drivers of variability in thermokarst lake water balance components (e.g. inflow, evaporation, lake level, lake water source composition), so that we may better understand how lakes will respond to ongoing climate change. Multiple properties of the environment have the potential to influence thermokarst lake water balances: seasonal and inter-annual variation in meteorological conditions (i.e. air temperature and precipitation), watershed properties (e.g. surface area, vegetation, topography, permafrost), and lake properties (e.g. depth, surface area, outlet channel presence). Achieving the objective of this thesis involves measuring lake water balances and quantifying how the environmental properties described ...