Experimental Design for Crosshole Electrical Resistivity Tomography Data Sets

We plan to employ crosshole electrical resistivity tomography for monitoring fast hydrological processes that involve complex interactions between a river that frequently floods and the adjacent groundwater. To obtain as much information as possible over relatively short periods, we need to optimise the electrode configurations that will be used to acquire the resistivity data. For this purpose, we have adapted an experimental design procedure first introduced for the planning of surface electrical resistivity surveys. Our new experimental design algorithm seeks electrode configurations for which the linear dependencies are low, such that each electrode configuration provides information that is largely independent of information supplied by all other electrode configurations. The resultant optimised electrode configurations yield overall resolution values and inter-borehole coverage that are superior to those supplied by a random selection approach.