2014 GSA Annual Meeting in Vancouver, British Columbia (19–22 October 2014)

Paper No. 18-9
Presentation Time: 10:15 AM

GEOPHYSICAL INVESTIGATION OF A GLACIAL AQUIFER SYSTEM IN A DEGRADING PERMAFROST ENVIRONMENT NEAR UMIUJAQ, NUNAVIK, CANADA, FOR 3D HYDROGEOLOGICAL MODELING PURPOSE


BANVILLE, David1, FORTIER, Richard1, LEMIEUX, Jean-Michel1, MOLSON, John W.1, THERRIEN, René1 and OUELLET, Michel2, (1)Centre d'études nordiques, Université Laval, 1065 ave de la Médecine, Québec, QC G1V 0A6, Canada, (2)Direction de l'aménagement et des eaux souterraines, Direction générale des politiques de l'eau, Ministère du Développement durable, de l'Environnement et de la Lutte contre les changements climatiques, 675, boul. René-Lévesque-Est, 8e étage, Québec, QC G1R 5V7, Canada

The Center for Northern Studies at Université Laval, in collaboration with the Quebec Ministry of Environment, has implemented a network of groundwater monitoring wells in a 2 km2 catchment basin located in the discontinuous permafrost zone, near the Inuit community of Umiujaq in northern Quebec, Canada. This network provides a unique opportunity to monitor changes in groundwater flow dynamics resulting from permafrost degradation. A 3D geological model is currently being developed for the catchment. This model will be the basis of a 3D hydrogeological model simulating coupled groundwater flow and heat transport in the catchment. These simulations will help assess the future availability and sustainability of groundwater as a source of drinking water for northern communities.

The studied catchment lies within a valley draining into Lac Guillaume-Delisle. The groundwater monitoring wells attest the presence of two aquifers: a shallow aquifer in a surficial littoral sand layer and a deep aquifer in glacio-fluvial sediments partly confined by frost-susceptible silty marine sediments. High-resolution aerial photographs, an airborne LiDAR digital elevation model and a map of Quaternary deposits are available to characterize the surface geology. Drilling logs provide subsurface data but it is considered too sparse to build a reliable 3D geological model.

Geophysical investigation using seismic refraction, induced polarization and ground penetrating radar was thus undertaken in order to infer the bedrock topography, the extend of ice-rich permafrost and the spatial distribution of aquitard and aquifer materials along several 2D transects across the basin. These geophysical methods are complementary, which increases the reliability of the interpretation. In addition, existing data from drilling logs help constrain inversion of geophysical data. All data is currently analyzed, synthesized and integrated into the SKUA-GOCAD software to build the 3D geological model. This model will be the cornerstone of future hydrogeological simulations intended to assess the impact of climate change on groundwater resources in the presence of degrading permafrost.

Session No. 18

T159. Groundwater in Cold Environments: Current Understanding and Challenges
Sunday, 19 October 2014: 8:00 AM-12:00 PM
109 (Vancouver Convention Centre-West)
Geological Society of America Abstracts with Programs. Vol. 46, No. 6, p.67
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