ABSTRACT
It is widely recognized that natural heterogeneity and the large spatial variability of hydraulic parameters control inltration within the vadose zone, groundwater storage, and the spread of contaminants. It is also well recognized that natural heterogeneity
is typically great and can have multiple spatial scales of variability. Conventional sampling techniques for characterizing or monitoring the shallow subsurface typically involve collecting soil samples or drilling a borehole and acquiring hydrological measurements or borehole geophysical logs. When the size of the study site is large relative to the scale of the hydrological heterogeneity, or when the hydrogeology is complex, data obtained at point locations or within a wellbore may not capture key information about eld-scale heterogeneity; especially in the horizontal direction. Integration of spatially extensive geophysical data with direct borehole measurements holds promise for improved and minimally invasive characterization and monitoring of the subsurface over a variety of resolutions and spatial scales.
