High Resolution Imaging of Vadose Zone Transport Using Crosswell Radar and Seismic Methods

摘要

Although borehole and outcrops provide some sampling there is a critical need to provide volumetric information between point measurements. For example, there is a need for information on heterogeneities at scales ranging from the centimeter to 10s of meters, as these features can alter contaminant transport significantly. At Hanford, heterogeneities of interest can range from localized phenomena such as silt or gravel lenses, fractures, clastic dikes, to large-scale lithologic discontinuities. These features have been suspected of leading to funneling and fingering, additional physical mechanisms that could alter and possibly accelerate the transport of contaminants to underlying groundwater. It has also been observed from the studies to date that over relatively short distances there are heterogeneities in the physical structure of the porous medium and structural differences between repacked soil cores and the field site from which the materials initially came. Crosswell geophysical measurements are one means to provide this information.