EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Experimental and numerical investigation of microparticle transport and deposition in the context of permafrost thaw

Madiha Khadhraoui1,3,4, John Molson1,3,4, and Najat Bhiry3,2
Madiha Khadhraoui et al.
  • 1Département de géologie et de génie géologique, Université Laval, Québec, Canada
  • 2Département de géographie, Université Laval, Québec, Canada
  • 3Centre d’études Nordiques, Université Laval, Québec, Canada
  • 4Centre québécois de recherche sur la gestion de l'eau, Québec, Canada

In natural porous environments, soil particle migration during flow plays an important role in soil stability and pollutant transport by affecting soil mechanical properties and water quality. In northern areas, permafrost degradation alters the subsurface connection pathways leading to mass movements and rearrangement of the soil. To date, few models have included the influence of temporal and spatial variations of flow velocity and porous media heterogeneity on the transport and deposition of suspended particles.

In this study, laboratory column experiments and a numerical model were used to investigate these issues. The laboratory column experiments were carried out under different flow rates and the effect of porous media heterogeneity was investigated using different grain size distributions. The soil columns were reconstituted from several samples taken in the studied site, the Tasiapik Valley, located in the discontinuous permafrost zone near Umiujaq, Nunavik, Québec. During the experiments, the spatio-temporal distribution of the porosity and the hydraulic conductivity was monitored using X-ray computed tomography imaging (CT-SCAN). Using the pore water velocity computed from the groundwater flow solution, the advection–dispersion transport equation with a first-order kinetic term for particle deposition was solved using the finite element model Heatflow/Smoker. The dependency of the attachment kinetics on the pore water velocity and on the porous media heterogeneity was included. The model was tested and validated with an analytical solution and calibrated with the experimental data. Our simulations highlight the roles of hydrodynamic conditions and soil characteristics on particle transport and deposition mechanisms and the susceptibility of the porous medium to thermo-suffosion in permafrost environments.

How to cite: Khadhraoui, M., Molson, J., and Bhiry, N.: Experimental and numerical investigation of microparticle transport and deposition in the context of permafrost thaw, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13611,, 2021.

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