Geophysical Investigations Supporting the Groundwater Model for the North Sea Island of Föhr

PhD Student and like to particitpate at the AGAP Quality Award. Global change including changes for groundwater systems endanger sensitive regions such as barrier islands. Especially saltwater intrusions pose an increasing risk for water quality in coastal areas. To evaluate climate change effects for these environments we need reliable hydrogeological models. To improve the hydrogeological model and estimate hydraulic properties for our investigation area – the North Sea island of Föhr – we use a combination of airborne electromagnetics, seismic reflections and borehole methods. By evaluation of borehole logging data a petrophysical characterization regarding resistivity and seismic velocity is possible. An empirical positive correlation between hydraulic conductivity and electrical resistivity is estimated. For structural analysis airborne electromagnetic data were inverted including a-priori constraints from seismic reflections. The resistivity distribution as well as seismic sections and velocities reveal glacial structures, e.g. buried valleys and a glaciotectonic thrust-fault complex.