Profile

Oleksandra Pedchenko
Postdoctoral fellow
Department of Geology and Geological Engineering
Laval University
oleksandra.pedchenko.1@ulaval.ca

Supervised by:

John Molson (Regular member)

Co-supervised by:

Richard Fortier (Regular member)

Jean-Michel Lemieux (Regular member)

Research project description

Numerical assessment of groundwater resource sustainability of a river talik system within a continuous permafrost environment

Introduction: Water supply in permafrost regions is problematic for local communities and for economic development including mining. Groundwater is a potential solution for maintaining a safe and sustainable water supply. River taliks are of particular interest but their potential is currently unknown. Climate change adds to this uncertainty but as permafrost thaws, is expected to increase availability of groundwater as a sustainable resource. We are developing a 3D numerical model of a well-characterized river-talik system near Salluit, Nunavik, (Québec) to explore the critical questions with respect to water supply sustainability under pumping. Objectives: This project will provide critical insights into the potential for groundwater pumping from river-talik systems in permafrost environments, to inform water supply stakeholders and to support northern economic development initiatives. The objective is to assess the potential of river-talik systems as water supplies, using Salluit as a well-documented example. Guidelines for evaluating other sites will be developed. Study sites: The study site is located near the Inuit community of Salluit in the far north of Nunavik (Quebec), Canada, within a zone of continuous permafrost. Quaternary deposits fill the bottom of the valley above the bedrock interface. The Kuuguluk River in the Salluit Valley discharges into the Sugluk Fjord. Alluvial sediments in the riverbed are made of glacio-fluvial sand, gravel, and boulders. After emergence following isostatic rebound, these deposits were invaded by permafrost due to the very cold climate. Due to heat transport by the river flow in summer, a talik has formed below the Kuuguluk River. A single pumping well located in the bedrock further up the valley extracts groundwater from this river talik which is used as a source of drinking water by the local community. Understanding the dynamics of complex river-talik systems is fundamental for the sustainable use of drinking water for remote Inuit communities. Material and methods: The methodology of this project comprises the following steps: Review and treatment of existing background information and data from the Salluit field site. Review of the existing conceptual model and the 3D numerical cryo-hydrogeological model of the Kuuguluk river-talik system, Salluit. Review of the HEATFLOW numerical code, input data structure model output, and graphics tools. Test model runs and reproduction of existing 3D site model simulation (which did not include pumping wells or climate change). Extending the existing Salluit numerical model domain to include a pumping well to explore the limits of suitable groundwater extraction under different climate change scenarios, including the parameter uncertainty analysis. Reporting and exchange with the local community of Salluit and the Quebec Ministry of Environment. Expected results: The developed numerical tool will provide new insights to help making critical decisions regarding the use of groundwater for water supply in permafrost environments. The model results will be available to the academic community, decision-makers and local communities who wish to make similar assessments of potential and sustainability of their water supply. Industry will also benefit by improved knowledge of whether river taliks, and groundwater in general, could provide additional possibilities for water supply in permafrost environments. By the end of the project term, a research paper will be prepared and submitted for publication in a leading international peer-reviewed journal. A final report will be targeted for a broader audience. It will include practical guidelines and conclusions regarding the sustainable water supply at Salluit, with implications for other sites.

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