Abstract
Fractures and conduits in the vadose zone can significantly affect the groundwater-surface runoff interaction. Electrical geophysical methods have the potential to provide important information regarding saturation evolution in the fractured vadose zone in the field. Integrating numerical models with the field data can improve the interpretation of the field electrical measurements. In this study we develop and present an advanced method for coupled simulation of variably saturated fluid flow and electrical current distribution in an explicitly fractured porous media. In this model, the fractures are simulated with the hybrid-dimension approach (i.e. 1D fracture elements and 2D matrix elements) discrete fracture matrix model. Mixed hybrid finite element method, previously shown to be significantly more efficient that the conventional finite element method for highly heterogeneous domains, has been used as the numerical method of discretization for both fluid flow and electrical current. The results of the numerical solution are validated by comparing against the results obtained by a finite element based package for three synthetic configurations and the results show that the developed model exceeds the computation performance of the finite element counterpart. The developed model is then used to investigate impact of fracture geometry and the influence of electrical dipole configurations on the simulated electrical response. This work is the preliminary study of a highly efficient new tool for the coupled simulation of water flow and electrical current in fractured vadose zone.