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An optimized workflow for regional aquifer characterization in Montérégie, Québec, Canada.

Gloaguen, Erwan; Blouin, Martin (2014). An optimized workflow for regional aquifer characterization in Montérégie, Québec, Canada. In: Symposium on the Application of Geophysics to Engineering and Environmental Problems 2014 (SAGEEP 2014)., 16-20 mars 2014, Boston, États-Unis.

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Résumé

Because of the threat on groundwater supply by anthropic activities, the growth of the population and the global warming, the inventory of regional groundwater resources became a major concern in most industrial countries. In 2009, the ministry of environment of the province of Quebec (Canada) funded a huge characterization program aiming to improve the knowledge of the groundwater resources throughout the municipalized areas of Quebec. Our group was mandate to built a characterization workflow and apply it to the regional aquifer of Montérégie Est that covers an area of approximately 9000 km2 North-East of Montreal city. The surveyed area has approximately 577 000 inhabitants, of whom 28% use groundwater as a source of supply. The most important step in such characterization program consists in predicting the challenges in data integration before going to the field. Hence, the project required developing specific data assimilation algorithms that take into account the different scale and resolution of the in situ characterization tools. A coarse to fine characterization was chosen, first starting with the mapping of surficial quaternary deposits. Then, based on geological knowledge regional seismic reflexion, ground-based and airborne TEM were measured to image the regional continuity of the quaternary deposits so as to map the unconsolidated sediment-bedrock interface. Based on this information the sites for cone penetration test with electrical and permittivity sensors were decided and wells were installed up to the bedrock at location were the petro-physical relations show different patterns than those previously sampled. Finally, core and water sampling and hydraulic testing were done. The data integration starts firstly, by importing all the data into a 3D GIS to cross-validate the indirect information with well data. The main surfaces are then interpolated using adapted kriging with external drift that take into account the resolution of each technique. Secondly, petro-physical analysis is computed within each lithology. Finally, three-dimensional multivariate interpolation is computed over the entire surveyed area to estimate the spatial variability of the regional lithology. This allowed to better understanding the genesis of the unconsolidated material that in return permits to improve the knowledge of regional groundwater flow.

Type de document: Document issu d'une conférence ou d'un atelier
Mots-clés libres: hydrogeophysics; regional aquifer characterization; data assimilation
Centre: Centre Eau Terre Environnement
Date de dépôt: 31 août 2017 20:35
Dernière modification: 31 août 2017 20:35
URI: http://espace.inrs.ca/id/eprint/3589

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