AUFEIS MAPPING AS A TOOL FOR GROUNDWATER INVESTIGATION IN THE NORTHWEST TERRITORIES

ABSTRACT: Aufeis (icings) are accumulations of layered ice that form mainly during winter on the ground surface or on river or lake ice, by freezing of successive flow of water that may seep from the ground, flow from a spring or emerge from below river ice through fractures. These periglacial features can be present in seasonal-frost environments, but are most likely to occur in permafrost regions where the frozen ground acts as an impermeable barrier and forces groundwater flow to the surface via preferential flow paths. Recurrent large aufeis features are particularly of interest for groundwater investigation as they are often related to groundwater discharge locations. As groundwater knowledge in the Northwest Territories (NWT) is sparse and hard to acquire, aufeis mapping could be a cost-effective tool for groundwater characterization and monitoring. A few initiatives in the past decade have mapped these features at a regional scale using satellite imagery. The objective of this current project is to refine the methodology previously developed to identify large icings at a broad spatial scale in NWT. The outputs of the project will be of interest from a groundwater perspective, as they have the potential to (1) indicate spatial patterns of groundwater resurgence, (2) identify relevant groundwater monitoring locations, (3) provide a basis for further research on cumulative impacts of base flow at a watershed scale, and (4) provide a useful tool to follow the evolution of permafrost and groundwater dynamics in the context of climate change.