My areas of focus span the wide range of arid region hydrology, with particular interest in bridging the gap between hydrogeology and soil physics in the newly emerging area of vadose zone hydrology. I am currently involved with studies of moisture flux and groundwater recharge in arid environments. Other work includes the development of soil-atmosphere models of energy and water flux, the study of ground-water/brine interactions in terrestrial environments, the reconstruction of paleoclimates from soil water chemistry, and reactive transport of contaminants in fractured, dual porosity unsaturated media and mine waste materials.