His research areas are mathematical models of hydrological and vadose zone processes and applied mathematical methods. He is currently researching water infiltration and its relationship with non-linear solute adsorption processes as well as the effect of subsurface heterogenity on chemical transport. Other research interests include contaminant sorption in soil profiles, unsaturated flow, transport of organic liquids, saltwater intrusion and centrifugal modelling of solute transport processes. He has published over 80 refereed technical papers.