| Title | Comparison between hydraulic conductivity anisotropy and electrical resistivity anisotropy from tomography inverse modeling |
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| Author | Gernez, S; Bouchedda, A; Gloaguen, E; Paradis, D |
| Source | Frontiers in Environmental Science vol. 7, 67, 2019 p. 1-15, https://doi.org/10.3389/fenvs.2019.00067  Open Access |
| Image |  |
| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20180391 |
| Publisher | Frontiers Media SA |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf (Adobe® Reader®); html |
| Province | Quebec |
| NTS | 21L/11 |
| Area | Saint-Lambert-de-Lauzon |
| Lat/Long WENS | -71.3247 -71.2578 46.6150 46.5800 |
| Subjects | hydrogeology; geophysics; surficial geology/geomorphology; Science and Technology; groundwater resources; aquifers; groundwater flow; hydraulic conductivity; electrical resistivity; anisotropy;
modelling; geophysical surveys; electrical surveys; sediments; alluvium; silts; sands; glacial deposits; tills; organic deposits; beach ridges; scarps; landfill sites; open pits; surface waters; wetlands; swamps; lakes; streams; observation wells;
Methodology; alluvial sediments; Phanerozoic; Cenozoic; Quaternary |
| Illustrations | location maps; geoscientific sketch maps; models; geophysical images; plots; bar graphs; histograms; schematic representations |
| Program | Groundwater Geoscience Aquifer Assessment & support to mapping |
| Released | 2019 06 04 |
| Abstract | Hydrogeophysics is increasingly used to understand groundwater flow and contaminant transport, essential basis for groundwater resources forecast, management, and remediation. It has proven its ability
to improve the characterization of the hydraulic conductivity (K) when used along with hydrogeological knowledge. Geophysical tools and methods provide high density information of the spatial distribution of physical properties in the ground at
relatively low costs and in a non-destructive manner. Amongst them, the Electrical Resistivity Tomography (ERT) has been widely used for its high spatial coverage and for the strong theoretical links between electrical resistivity (rho) and key
hydrogeological parameters, such as K. Historically, ERT data processing was based on isotropic hypothesis. However, the unconsolidated aquifers in Canada reveal in most cases a strong anisotropic behavior for K both with in situ or laboratory
measurements. Recently, electrical anisotropy has been considered model-wise, but it is seldom considered as an interpretation tool or in the characterization process of the anisotropy of K. In order to evaluate the potential of ERT to assess the
anisotropy of electrical resistivity, we developed a forward and inverse modeling code. These codes have been validated and tested on a realistic synthetic case reproducing the behavior of a real aquifer extensively characterized, the site of
Saint-Lambert-de-Lauzon in Quebec (Canada). On this site, innovative in situ hydraulic tomography has revealed a strong anisotropy, with up to three orders of magnitude between horizontal and vertical K components. In order to confirm the link
between in situ K- and rho-anisotropies, an ERT survey has been performed, using the same wells as for the hydraulic tomography. The inversion confirms a strong link between K- and rho-anisotropies. It demonstrates the suitability of the anisotropic
ERT approach coupled with well measurements to provide better estimates of K and its anisotropy at the scale of a site. |
| Summary | (Plain Language Summary, not published)
This research present a novel approach to estimate hydraulic anisotropy of the subsurface from geophysical data (electrical resistivity). Hydraulic
anisotropy is an important parameter to know to understand groundwater flow, and very few methods exists to estimate it. The practical developments made in this research will greatly contribute to the hydrogeology industry (scientists,
engineers). |
| GEOSCAN ID | 313615 |
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