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- Title
Three‐Dimensional Numerical Modeling of Cryo‐Hydrogeological Processes in a River‐Talik System in a Continuous Permafrost Environment.
- Authors
Liu, Weibo; Fortier, Richard; Molson, John; Lemieux, Jean‐Michel
- Abstract
In continuous permafrost environments, understanding complex river‐talik system dynamics is fundamental for the sustainable use of talik aquifers as a source of drinking water in remote communities. A conceptual model of a river‐talik system was previously developed based on field investigations in the floodplain of the Kuuguluk River at Salluit, Nunavik (Quebec), Canada, including geophysical surveys and monitoring of hydraulic heads and riverbed temperatures. This conceptual model is here used to develop a 3D numerical model for simulating the governing cryo‐hydrogeological processes and dynamic system behavior. The numerical simulations, supported by the field data, show that the width and thickness of the river talik is highly correlated to the width of the overlying riverbed. In summer, the river talik is hydraulically connected to the riverbed, and groundwater from the talik aquifer is contributing to river baseflow. In winter, when the river and riverbed freeze, the river talik becomes hydraulically isolated from the riverbed. Under such conditions, the river talik acts as a tube‐like conduit system which focusses groundwater flow. Increasing hydraulic heads at constrictions in the talik can be sufficient to fracture the frozen riverbed and ice cover, leading to groundwater overflows and icing formation. This study presents an integrated field and modeling approach for assessing the potential of talik aquifers as reliable sources of drinking water in northern communities. Plain Language Summary: Finding a reliable source of drinking water in very cold climates is a challenging task for the sustainable development of northern communities. On the one hand, surface water is vulnerable to contamination and can freeze in winter. On the other hand, groundwater stored as ice in permanently frozen ground, called permafrost, is not readily available for use. However, extractable groundwater in permafrost environments can often be found below surface water, including groundwater below rivers. Heat transport from the relatively warmer river water can be enough to maintain a zone of unfrozen ground below the riverbed, called a river talik. For example, the Inuit community of Salluit (Nunavik, Canada) is currently extracting groundwater from a river talik as a source of drinking water. Understanding the dynamics of this complex river‐talik system is fundamental for sustainable use of this natural resource. To improve our understanding of this system, we have undertaken field investigations to monitor water levels and temperatures in the riverbed, and to delineate the river talik using geophysical methods. We have also developed and applied a 3D numerical model to simulate the governing physical processes of groundwater flow and heat transport in and around the river talik. In winter, increases in groundwater pressure at talik constrictions are sufficient to crack the ice cover, which induces groundwater overflow, and enlarges the ice cover. The study presents a useful integrated field and modeling approach for assessing the potential of talik aquifers as reliable sources of drinking water in northern communities. Key Points: Numerical modeling supported by field investigations shows that the size of the river talik is correlated to the width of the river channelThe river talik is hydraulically connected to the riverbed in summer but is hydraulically isolated in winter due to freezing of the riverbed and icing formationWhen the talik is hydraulically isolated in winter, increases in hydraulic head at talik constrictions are enough to fracture the frozen riverbed and overlying ice which leads to groundwater overflows
- Subjects
CANADA; PERMAFROST; THREE-dimensional modeling; NATURAL resources; SUSTAINABLE development; GROUNDWATER flow; HYDROGEOLOGY; WATER levels
- Publication
Water Resources Research, 2022, Vol 58, Issue 3, p1
- ISSN
0043-1397
- Publication type
Article
- DOI
10.1029/2021WR031630