Surface Water Dynamics and Rapid Lake Drainage in the Western Canadian Subarctic (1985–2020)

Abstract

The area and distribution of surface water are shifting rapidly in many regions across the circumpolar Arctic. In this study, we explore the effects of climate and terrain factors on the area of lakes in the Northwest Territories, Canada. We used the Landsat satellite archive to map interannual changes in 5,328 lakes and ponds in the Lower Mackenzie Plain between 1985 and 2020. The high temporal resolution of our dataset allowed us to classify gradual and abrupt changes in the lake area and identify rapid drainage events. We used Generalized Additive Models and Random Forests to test the effects of climate and terrain factors on changes in the lake area. Despite increases in the area of smaller lakes driven by increasing precipitation, we found that the total lake area has decreased by approximately 1%. Overall, 29% of lakes exhibited an increasing trend in the area, while 11% exhibited a decreasing trend, and the majority of these changes (65%) were non‐linear in nature. Lakes located in fire scars were also 3.8 times more likely to show a decreasing trend in area. Analysis of a large fire indicates that lakes within the burned region exhibited declines in an area that persisted until the end of the study period 20 years after the fire. These declines are likely related to the impact of fire on thaw depth, groundwater connectivity, and the development of new drainage pathways. Our results highlight the importance of rapid drainage and wildfire as drivers of declines in the lake area.

Monitoring 13 years of drastic catchment change and the hydroecological responses of a drained thermokarst lake

“…Preliminary analysis conducted here indicated that pixels satisfying multiple thresholds resulted in conservative estimates of shoreline locations since accuracy of shorelines constrained from individual bands (i.e., NIR and SWIR) showed high variability for individual acquisition dates. A subpixel water fraction approach would likely have improved individual use of the SWIR band (Olthof et al 2015;Travers-Smith et al 2021). This technique includes interpolating the fraction of each pixel covered by water between a pure water threshold and pure land threshold.…”

“…In addition, it is likely that hydrological changes (e.g., lake area) detected using remote sensing approaches have been conservative where steep shorelines mask water-level fluctuations. Regardless, the frequency of lateral lake drainage events has clearly increased during recent decades in some vast northern permafrost landscapes in Alaska (Jones et al 2011;Jones et al 2019;Swanson 2019;Nitze et al 2020), northern Yukon, Canada (Lantz and Turner 2015), and in fire scars in the Lower Mackenzie Plain (Travers-Smith et al 2021). This underscores the need to enhance our knowledge of the immediate and long-term consequences of the remaining postdrainage aquatic and newly formed terrestrial environments.…”

Surface water area in a changing climate: Differential responses of Alaska’s subarctic lakes

“…As climate models project Alaska to become warmer and wetter, it is possible that we could see a landscape wetting before we cross a permafrost/glacial deterioration threshold and landscape-wide drying. Additionally, we did not consider the effects of wildfire history on lake surface area in this study, which has been shown to affect rates of lake surface area change in permafrost areas [60].…”

Automated Identification of Thermokarst Lakes Using Machine Learning in the Ice-Rich Permafrost Landscape of Central Yakutia (Eastern Siberia)

“…Boike et al [25] recorded an average increase of 17.9% in the total area covered by lakes between 2002 and 2009 in the central part of the Lena River catchment in the Yakutian region of Siberia (minimum lake size = 0.3 ha). Some areas of continuous permafrost, including the lower Mackenzie River, Canada and northern Alaska, have experienced declines in lake number and areas [26,27], whereas some other sites in the discontinuous zone did not show significant trends in lake number/area but rather a substantial increase in vegetation cover (e.g., [28]). Remote sensing techniques using satellite images have become a powerful tool for analyzing lake area change in the expansive regions of continuous permafrost found in Eastern Russia.…”