RECENT STUDIES OF FLOW AND TRANSPORT IN THE VADOSE ZONE

Vadose zone hydrology has received increased attention in recent years as a result of environmental concerns over potential groundwater pollution from buried wastes. Funding agencies have supported several comprehensive field studies designed to improve and test models that describe flow and transport of contaminants in heterogeneous field soils. Extensive data bases, containing measured hydraulic properties and observations of flow and transport, have been established and have been useful for model testing and comparison. Improvements in stochastic and deterministic modeling capabilities for the vadose zone have been made. The stochastic models provide a way to account for site variability. The improved deterministic models conserve mass and are computationally efficient. This paper discusses recent progress in the areas of model validation, stochastic and deterministic analysis, multiphase flow and transport, preferred pathway analysis, and other related topics.