A field assessment of site‐specific correlations between hydraulic and geophysical parameters

Abstract

ABSTRACTIn this study the potential of combining high‐resolution hydraulic tomographic and geophysical tomographic measurements to define site‐specific relationships between geophysical and hydraulic parameters was investigated. We exploit the high‐spatial resolution of hydraulic and geophysical tomographic images to define a representative and reliable site‐specific relationship, if it exists, over an area, where geophysical and hydraulic tests are performed. The parameters involved in this study were: seismic P‐wave velocity derived from seismic tomography; resistivity and electrical conductivity derived from electrical tomography (ERT); diffusivity, hydraulic conductivity and specific storage derived from hydraulic tomography. We derived a site‐specific correlation function between the parameters P‐wave velocity and diffusivity that shows the highest correlation of all hydraulic and geophysical parameter combinations. The transformation of the P‐wave velocity field into a diffusivity field using the estimated site‐specific correlation function allowed us to increase the significance of hydraulic tomographic as well as seismic tomographic measurements with respect to the spatial diffusivity distribution in the near subsurface.