The focus of Subproject 7 lies in the model-based reconstruction of groundwater salinization along the northwestern German coast resulting from prehistoric, historical, and potentially future storm surge events. The aim is to quantify the impact of individual storm surge events on salinization dynamics, enabling reliable assessments of the timescales for salinization and subsequent freshwater recovery. To date, a systematic understanding of how individual storm surge events have shaped the long-term evolution of groundwater salinity is lacking —knowledge that is crucial for protecting groundwater resources in the context of dike breaches and climate change.

For the planned modeling work, an existing density-dependent paleo-groundwater flow model for Northwestern Germany is employed. New data on prehistoric and historical storm surge events, as well as paleotopography, will be integrated into the model in close collaboration with NIHK (TP 6). Future scenarios are used to assess potential dike breaches and their regional impacts on groundwater salinization. Key factors such as flood probability, extent, and duration of saltwater intrusion are critical in determining the spatial and temporal distribution of groundwater salinization.