Mesh design for electrical resistivity imaging of agricultural dikes

Abstract Electrical resistivity imaging (ERI) shows promise for investigating earthen flood barriers. We are interested in the applicability of ERI for aiding maintenance and construction efforts on agricultural dikes in the upper Bay of Fundy, Canada. An overarching research goal is to develop efficient survey and data processing procedures for detecting internal issues in such dikes ahead of more detailed investigations. We are developing detailed field survey and inverse modelling protocols to help us reliably target hypothetical subsurface features, and this article presents a critical step in that process: we performed a detailed investigation to assess and adapt existing common practices for three‐dimensional (3D) inversion mesh design for seawater‐adjacent agricultural dike‐imaging scenarios. We worked in 3D because dikes have significant 3D geometry and hence two‐dimensional inversion is unlikely to be adequate. We used a representative 3D dike model for the region and worked with the specifics of our surveying equipment, yet our conclusions may have wider ranging relevance. We investigated the effect of various mesh generation parameters on forward modelling accuracy, and we conclude by providing mesh design recommendations for dike investigations.