Electrical resistivity has been used successfully to characterize temporal change in water content in the vadose zone.  Currently, electrical resistivity is used indirectly to estimate parameters in hydrogeologic models.  A large number of apparent electrical conductivity measurements are collected and used with a numerical inversion scheme to provide a two- or three-dimensional distribution of electrical conductivity of the subsurface.  The electrical resistivity distribution is related to water content by a calibration function.  This distribution can then be used to constrain a hydrologic inverse model to estimate hydrologic parameters.  This is a state-oriented approach in which the full state (water content distribution) of the region of interest is determined in each time step.  We propose a process-oriented approach whereby only those data required to identify the parameters controlling the hydrologic process through time are collected.  This approach is developed by coupling a hydrologic model with an instrument response model facilitating direct study of parameter identifiability from electrical resistivity measurements.  Initial analyses show that the sorptivity and hydraulic conductivity in the Philip two term infilitration model can be identified based on electrical resistivity measurements.  Further analyses show that measurements made during both driven (infiltration) and relaxing (redistribution) processes lead to more complete descriptions of soil hydraulic properties.