Numerical simulator
The numerical simulator used for the simulations in this study is the EOS3 module of the integral finite difference code named TOUGH2 (Pruess et al., 1999). TOUGH2 has been used successfully in many geothermal and nuclear waste disposal studies (e.g., Sonnenthal and Bodvarsson, 1999; Haukwa et al., 2003). The EOS3 module of the code is developed for simulating the transport processes of water, air, and heat in porous media. As a result, it can be used to simulate unsaturated infiltration in soil.