Time-Lapse GPR Imaging of Subsurface Flow Processes During a Hillslope Irrigation Experiment

For a better understanding of hydrological processes in the subsurface, hydrologists need information on different spatial and temporal scales. Geophysical methods provide the opportunity to image and monitor subsurface flow processes beyond point information. In particular, ground-penetrating radar (GPR) is a promising method because it allows for fast data acquisition paired with high spatial resolution. Such characteristics are considered to be critical when monitoring fast temporal and small spatial changes in the subsurface. In this study, we present a field data example of time-lapse GPR reflection measurements to monitor subsurface flow processes induced by an irrigation experiment. We use similarity attributes to analyze our recorded data and to visualize drainage dynamics at a hillslope section in the Ore Mountains, Germany. Our results demonstrate the feasibility of GPR measurements to provide spatiotemporal information on subsurface flow processes at spatial scales of a few decimeters and at temporal scales of a few minutes.