Expertise Flow and contaminant transport in vadose zones and aquifers; numerical, stochastic/geostatistical, field, and laboratory analysis of effects of spatial variability on flow and contaminant migration in the subsurface; development of rapid methods for characterizing transport propertise of multi-phase flow; development of cost-effective imaging tools for characterizing geological media and monitoring evolutions of water, oil, and contaminants in the subsurface using hydro/geophysical techniques