Collaborative Research: Watershed-scale Geomorphic Response to Climate Change in the Aklavik Range, NWT (Canada)

Arctic landscape response to rapid anthropogenic climate change has the potential to fundamentally alter both human and natural systems. This includes increased hazards to Arctic communities from permafrost thaw and associated slope instability and the destruction of river and coastal habitats from higher sediment and nutrient yields in Arctic rivers. While it is clear that Arctic landscapes are sensitive to climate change, a gap exists in our knowledge about how changes in temperature will affect the ways in which sediment is transported across a watershed. In order to address this knowledge gap, the investigators will be conducting a field- and remote sensing-based study of Arctic watersheds in the Aklavik Range of the Northwest Territories (NWT), Canada, where numerous First Nations communities are situated. The research team will test the specific hypothesis that climate change in the Arctic is leading to faster production of sediment within mountainous regions and causing subsequent increases in sediment delivery to hillslopes and rivers. This is an interdisciplinary project that involves three Early Career tenure-track faculty, multiple local collaborators, as well as the Ehdiitat Gwich’in. The investigators will study two small bedrock watersheds (where sediment is produced) and their associated fan deposits (where sediment is stored) along a north-south climate gradient. Prior geomorphic work on these fan deposits was conducted in the 1960s to 1980s, making them an ideal location to quantitively assess change over time. The major objectives are to: (1) conduct fieldwork to understand how sediment is produced and the processes by which it moves across this landscape; (2) perform laboratory analyses on samples collected in the field to quantify rates of sediment production and transport over decadal to millennial scales; (3) use remote sensing techniques to extend local findings to the broader region over the last several decades; and (4) to use these data to calibrate sediment production and transport models so that we can predict future Arctic landscape response to anthropogenic warming scenarios. Many of the dating and remote sensing techniques have greatly advanced in the last several decades, but have not been applied to an integrated Arctic study spanning an entire watershed. Once proven in this study, this combination of methods could be used in other landscapes (both in the Arctic and at low latitudes) to better quantify how changes in rates of one geomorphic process (e.g., breakdown of bedrock) affects changes in rates of another (e.g., rates of sediment delivery to a river). In addition, the data collected during this project will calibrate state-of-the-science models allowing scientists to better inform local communities of potential hazards due to future warming. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.