Parameter resolution of simulated responses to periodic hydraulic tomography signals in aquifers

An accurate assessment of the hydraulic properties of aquifers is required to represent groundwater flow and solute transport. This study investigates periodic hydraulic tomography performed between wells to obtain accurate images of hydraulic properties. Tomographic experiments with different period and amplitude of sinusoidal test flow, hydraulic properties and well configurations were simulated with a numerical flow model. An l-curve analysis of the obtained heads and sensitivities identified the optimal parameter resolution and served as a basis for comparing the experiments. The results show that the transient phase of signals with short periods provides the most information about the resolution of the aquifer. The resolution could be further improved if tests with different periods were properly combined in the analysis. The study concludes that periodic tomography provides valuable insight into the spatial resolution of hydraulic conductivity and its vertical anisotropy and specific storage, but the choice of signal characteristics is critical.