Geoscience Data Compilation for Groundwater Mapping across the Alberta and Northwest Territories Transboundary Region

Knowledge of groundwater in the Alberta-Northwest Territories transboundary region is limited despite its significance in managing resources within our shared basins. Hydrogeological information is scarce and aquifers in this region have not been fully mapped. To address this challenge, the Alberta Geological Survey, in collaboration with the governments of Alberta and Northwest Territories, is seeking to better understand transboundary groundwater by collecting empirical data, developing conceptual models, and mapping aquifers. Initial efforts focused on assessing subsurface data to support aquifer delineation in the transboundary region, including creating maps of bedrock topography and sediment thickness. Data compilation was required relying on lithological observations from various borehole types, water level and chemistry data from groundwater wells, and geophysical logs, drill cuttings and stratigraphic tops from hydrocarbon wells. Preliminary geological mapping identified significant discrepancies in the estimated sediment thickness above bedrock. Different data sources between Alberta and Northwest Territories and geological mapping methods caused the variability. Data harmonization followed by new mapping and building regional cross-sections was performed to create a unified geological model for evaluating groundwater resources. Water samples from the Hay River and wells in the sub-basin were collected for geochemical and isotopic analysis. Data integration of aquifer mapping with our water geochemistry will be used to develop an understanding of groundwater-surface water interaction and circulation pathways in sediment and bedrock aquifer systems. Resolving data fragmentation issues allowed us to conduct the hydrogeological characterization needed to inventory transboundary groundwater that is important for establishing governance of shared resources. Future work will acquire new data to aid in quantifying groundwater conditions and devise monitoring programs in the Alberta-Northwest Territories transboundary region.