Characterizing Aspects of Groundwater Flow in Discontinuous Permafrost Terrain, Within the Central Mackenzie Valley, NWT

• Main Author: Wicke, Andrew
• Format: Master Thesis
• Language: English
• Published: University of Waterloo 2021
• Subjects: permafrost; baseline monitoring; groundwater; geochemistry; isotopes; Northwest Territories; Mackenzie River; Mackenzie Valley; Martin House; Bogg Creek; Mackenzie river
• Online Access: http://hdl.handle.net/10012/17025

With recent developments in oil and gas exploration technologies that have opened regions of Canada’s northern territories and the threat of climate change, uncertainties around how these factors may impact the environment in these areas are profuse. To reduce uncertainty and allow for mitigation planning, having effective baseline monitoring of environmental systems, such as groundwater, is critical. However, baseline monitoring studies of groundwater resources in these regions are complex and expensive to undertake as compared to studies in more southern regions. This is due mainly to the remoteness, lack of infrastructure and presence of discontinuous permafrost that complicates the use of traditional groundwater monitoring methods in northern regions. The work outlined in this thesis set out to improve baseline monitoring studies of groundwater in discontinuous permafrost areas. A suite of geochemical and isotopic tracers combined with physically based hydrologic measurements were tested in two summer field campaigns within the Bogg Creek Watershed, a small subcatchment of the Mackenzie River in the Northwest Territories (NWT). These data were acquired through strategic sampling utilizing portable and lightweight equipment, guided by previous remote sensing work and an aerial infrared survey. This field data was combined with a variety of other data sets acquired through public records and reports, as well as through collaboration with interested third parties. Physical data provided evidence for groundwater discharge in some areas, while the geochemical and isotopic evidence allowed for fingerprinting of these groundwater sources. In total, 5 groundwater source groups were identified in the study area. These included shallow seepage water and organic active layer porewater (both Ca-SO4¬), suprapermafrost groundwater originating from mineral soils (Ca-HCO3), subpermafrost groundwater from the Little Bear Formation aquifer (Na-HCO3), and subpermafrost groundwater from the Martin House Formation (Na-Cl/HCO3). ...