Modelling the effects of porous media deformation on the propagation of water-table waves in a sandy unconfined aquifer

Abstract

In this paper, the influence of porous media deformation on the dispersion of water table waves in an unconfined aquifer was examined using a numerical model which coupled Richards' unsaturated flow equation to the poro-elastic material model. The dispersion of the water table wave was quantified via the complex water table wave number which was extracted from the predicted amplitude and phase profiles. The motivation for the present study is the observed model-data discrepancy of Shoushtari et al. (2016). The observed wave dispersion (amplitude decay and phase lag) was unable to be reproduced with analytical solutions (including capillarity and vertical flow effects) or a numerical solution of Richards' equation (with and without hysteresis effects). The discrepancy inherent in the comparison is that there is more energy dissipation in the observations (faster decay rate and greater phase lag) than is predicted by any of the models. This paper examines whether deformation of the