Imaging of Fluid Flow in the Subsurface

, Center for Geophysical Investigation of the Shallow Subsurface

Our goal is to develop cost-effective, non-invasive methods for quantitatively characterizing the distribution of permeability in heterogeneous aquifers and/or imaging subsurface variation in materials and material properties using hydrologic and geophysical techniques. These capabilities have been identified as high priorities for reducing risk, uncertainty, and cost at contaminated sites by EPA, DoD, DOE, and NRC. Permeability is the most significant aquifer parameter for quantitatively describing or modeling groundwater flow and contaminant transport, and for designing remediation systems.

The Boise Hydrogeophysical Research Site (BHRS) is an in situ field-scale test facility (research wellfield) developed by the Center for Geophysical Investigation of the Shallow Subsurface (CGISS) in a shallow, heterogeneous, fluvial aquifer. At the BHRS we are thoroughly characterizing the wellfield as a control volume with "known" 3-D distributions of sedimentary facies, geophysical parameters, and hydrologic parameters. Then responses from geophysical methods, alone and together, can be related to the known hydrologic parameter distributions for mapping the 3-D distribution of permeability with inverse and/or stochastic modeling techniques.

Initial efforts have concentrated on three generally accessible geophysical methods: seismic, ground penetrating radar (GPR) and electromagnetic methods. Recent efforts also have included development of new field techniques, theory, and modeling methods for time-lapse imaging with radar and electrical resistivity tomography, and for hydraulic tomography.