The primary objective of the Vadose Zone Transport Field Study is to obtain hydrologic, geophysical, and geochemical data from controlled field studies to reduce the uncertainty in vadose-zone conceptual models and to facilitate the calibration of numerical models for water flow and contaminant transport through Hanford's heterogeneous vadose zone. A secondary objective is to evaluate advanced, cost-effective characterization methods with the potential to assess changing conditions in the vadose zone, particularly as surrogates of currently undetectable high-risk contaminants. The study is designed to assure the measurement of flow-and-transport properties in the same soil volume, a pre-requisite for developing techniques for extrapolating parameters derived from investigations at clean representative sites to contaminated sites with minimal characterization.