The electrical resistivity tomography as a tool for groundwater prospecting in the flysch lithologies: a case study from Poland

Abstract Sustainable water management is particularly important in mountainous areas, where access to surface water is limited and drilled wells often remain the only reliable source of fresh water. Locating aquifers in such regions is challenging due to the complex geological conditions. In this context, geophysical methods, especially electrical resistivity tomography (ERT), can provide valuable support in identifying zones with higher groundwater potential in areas such as the Carpathian flysch, composed mainly of sandstones and shales occurring in varying proportions. The paper presents case studies from the Magura and Silesian Nappes, demonstrating how ERT surveys, verified by borehole data, helped indicate aquifer locations and assess hydrogeological conditions. The application of ERT in the specific geology of the Carpathian flysch allowed for the identification of the influence of lithological proportions and water mineralisation on the values of electrical resistivity and the summary of the limitations and possibilities of the ERT method in difficult mountain conditions. Although heterogeneous geological settings may limit the precision of interpretations, the results confirm that ERT is an effective tool for improving the recognition of groundwater resources in mountainous flysch areas and thus giving people access to water.