NWT RESEARCH DATABASE

Regions: Sahtu Settlement Area

Tags: hydrology, discontinuous permafrost, permafrost thaw

Objective(s): The main objective of the proposed research is to continue investigating the groundwater flow conditions within the Central Mackenzie Valley of the Northwest Territories (NWT), with a specific focus on how permafrost discontinuity and thaw processes will influence groundwater circulation and interaction with surface water bodies. Changing subsurface conditions will influence landscape features, hydrology, habitat and ecosystem, and stability of constructed infrastructure.

Project Description: This licence has been issued for the scientific research application No. 5990. The main objective of the proposed research is to continue investigating the groundwater flow conditions within the Central Mackenzie Valley of the Northwest Territories (NWT), with a specific focus on how permafrost discontinuity and thaw processes will influence groundwater circulation and interaction with surface water bodies. Changing subsurface conditions will influence landscape features, hydrology, habitat and ecosystem characteristics along with presenting challenges for the stability of constructed infrastructure. Mapping the nature and location of subsurface permafrost conditions is of interest for many applications and has proven to be both extremely challenging and costly, especially within a discontinuous permafrost environment. Airborne electromagnetic (AEM) survey methods combined with terrestrial geophysical surveys, geological information and local physical and geochemical data have proven promising in mapping permafrost occurrence and continuity on a regional scale within the Bogg Creek watershed near Norman Wells, NWT. Building on this success, highly targeted terrestrial geophysical surveys, employing a range of survey methods, can be used to further advance the understanding of the subsurface hydrology at the Bogg Creek field site. These data combined with shallow coring and surface water and soil gas sampling will permit a more detailed quantification of carbon release from this remote landscape and will provide unique insight into the source of the carbon and specifically the role of permafrost thaw in controlling carbon release. The combined field studies will elucidate the role of groundwater in the changing hydrologic and ecologic conditions, along with related potential impacts on wildlife habitat in the northern landscape as the climate warms. The new research activity will also contribute to understanding how the processes of permafrost thaw are influencing the release of entrapped chemical species from the subsurface including carbon, which is widely regarded as a potential factor in enhancing climate warming. Based on the promising results obtained from the previous AEM surveys on site and the insight obtained from the initial terrestrial geophysical surveys conducted last year, additional terrestrial geophysical surveys utilizing Electrical Resistivity Tomography (ERT), Ground Conductivity Meter (GCM), and Ground Penetrating Radar (GPR) will be conducted at a series of targeted locations within the watershed area. Specific areas of interest include near and between surface water bodies of various sizes to further understand how surface water bodies influence permafrost continuity. Surveys will also be conducted over different types of overburden materials to obtain additional information to support the detailed interpretation of the AEM data and across abandoned seismic lines of various ages to understand how local land clearing may influence permafrost thaw rates and refreezing. This will also have implications on the impact of wildfires on permafrost integrity. To document the potential impact on groundwater and surface water quality from the thawing of permafrost, shallow groundwater samples and surface water samples will be collected at locations documented to be groundwater discharge zones during previous field investigations. This will be combined with the collection and analysis of shallow soil cores from key locations in the watershed, building on the successful coring techniques used during last year’s field campaign. To quantify carbon flux, age and source in more detail, soil gas samples will be compared to the core analysis to identify the origins of carbon measured in water and soil gas, which will provide invaluable information and insight into the release of carbon from discontinuous permafrost terrain. The water and gas samples will be preserved and shipped to analytical laboratories in Edmonton and Ottawa. The core samples will be preserved and shipped to an analytical laboratory facility at the University of Ottawa for detailed investigation. Finally, all available data will be combined to support the further development of numerical modeling tools, which will ultimately be used to predict long term impacts of permafrost thaw as related to changing groundwater flow systems in a warming climate. One of the main communication mechanisms with community groups has been through video conferences and written document sharing. As part of the Research Licensing process, an update on the research progress and results have been shared with colleagues from the Sahtu Renewable Resources Board, Tulita Renewable Resources Council and the Norman Wells Renewable Resources Council. In preparation for the Summer 2024 field season, project results contained in an annual report prepared for the funding agency, Environmental Science and Research Board (ESRB), will be shared with these groups and the proposed 2024 work program will be presented and discussed during a virtual meeting planned for early June 2024. As with previous meetings, suggestions and guidance will be requested from the community leaders on priority topics to focus on as part of the continued research program. The team are also planning to provide an in-person presentation of the results and current activities while visiting Norman Wells, which will include a demonstration of the field equipment for both the Board members and local youth who may have an interest. Finally, the results of the research will be transferred to the Government of the Northwest Territories and Cenovus Energy through annual reports and presentations to collaborating groups. Ultimately, the students involved in the research work will aim to submit their research findings to appropriate journals for publication. The fieldwork for this study will be conducted from: July 17 - December 31, 2024