Studies at the U.S. Geological Survey Amargosa Desert Research Site have focused on characterizing factors and processes that control transport and fate of contaminants in arid environments. This paper summarizes research results that have been published through 1998. Results have improved understanding of water and gas movement through a thick unsaturated zone, including the degree to which features of the natural unsaturated-flow system can be altered by installation of a waste-disposal facility. The study of radioactive-contaminant transport at the site is at an early stage. Field data measured in association with this new component of research have generated speculation regarding the exact mechanisms that control tritium transport in arid unsaturated zones.
