Geophysical Monitoring Of Large-Scale Levee Overflow Experiments With Electric Resistivity Tomography

Abstract

Large scale overflow experiments allow testing erosion resistance of levee slopes under variable conditions, such as different soil parameters, grass lengths, presence of trees and presence of animal burrows. Within the scope of the Interreg-funded project Polder2C’s an extensive series of such experiments took place in Belgium and the Netherlands in 2020-2022 (Koelewijn et al. 2022). A variety of techniques was used to monitor critical parameters of those experiments, many of which were tried for the first time. One of them was Electric Resistivity Tomography (ERT) that was used to provide a time-series of images illustrating changes in the levee subsoil during testing. The experiment took place on a levee section where mole burrows had been previously detected, and where the presence of an extensive subsurface system of mole tunnels had been verified on the landward slope of the levee (figure 1).