Airborne Electromagmetic Survey to Map Permafrost in the Central Mackenzie Valley

Regions: Sahtu Settlement Area

Tags: physical sciences, electromagnetic survey, permafrost mapping

Principal Investigator: Rudolph, David (1)
Licence Number: 17022
Organization: University of Waterloo
Licensed Year(s): 2022
Issued: Apr 29, 2022

Objective(s): To utilize and assess the capacity of an airborne electromagnetic survey method to map permafrost occurrence and continuity on a regional scale.

Project Description: This licence has been issued for the scientific research application No.5240.

Within the Central Mackenzie Valley of the Northwest Territories (NWT), discontinuity and rapid change within the regional permafrost is anticipated to be influencing landscape, 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. The main objective of this research project is to utilize and assess the capacity of an airborne electromagnetic (AEM) survey method to map permafrost occurrence and continuity on a regional scale. Detailed field investigations have been completed near Norman Wells, NWT over the last decade related to environmental monitoring in advance of hydrocarbon exploration and changing climatic conditions. Much of this work has been focused within the Bogg Creek watershed situated along the western shore of the Mackenzie River between Norman Wells and Tulita, NWT. Field data have indicated a high variability of the depth to the permafrost table and the overall thickness of permafrost across this watershed region. The area contains a wide range of lake and stream sizes, diverse landscape conditions and road infrastructure. This area will be the focus of the AEM survey. The results will then be examined an evaluated in terms of the ability of this remote sensing system to map permafrost for a wide range of application.

Utilizing the information available from the Bogg Creek watershed, a Resolve6 AEM survey is proposed to map the occurrence and continuity of permafrost within the watershed area. A series of survey areas are considered, which incorporate a wide range of targets of interest that were anticipated to influence the nature of the underlying permafrost. Close survey line spacing (70 m) will permit a high degree of resolution in the subsurface imaging and will provide detailed insight into the capabilities of this AEM method to map permafrost continuity within this type of environment. The raw survey data will be numerically inverted with a computer modeling platform to develop two dimensional cross sections and three dimensional images of the subsurface apparent resistivity. The inverted data will then be interpreted for the distribution of permafrost, utilizing information and data from the Bogg Creek watershed studies to ground truth and support the interpretations. The interpreted data will then be used to access the influence of surface water body type and size along with land cover variability on permafrost occurrence.

The research team will provide reports and plain language materials detailing the progress and findings to interested parties. Researchers on the project are active in the Ne K’? Dene Ts'i?li? Forum, which provides a regular opportunity for research updates to community members, government, and other scientists. Researchers on the project will meet annually with representatives from the Sahtú Renewable Resources Board, ideally through the annual meeting of the Ne K’? Dene Ts'i?li? Forum and the Norman Wells and Tulita Renewable Resources Council to discuss research findings.

The fieldwork for this study will be conducted from April 29, 2022 to December 31, 2022