By combining aerial imagery with spatially paired ADCPs upstream and downstream of a large-scale groyne, we were able to isolate and quantify complex fluid-structure-sediment interactions.
Key highlights from the study:
We captured unique tidal hydrodynamics before, during, and after intense storm conditions. Thus, providing the first explicit differentiation between episodic storm responses and recurring tidal processes at groyne-scale structures. We quantified five distinct surface turbidity patterns, linking them to subsurface hydraulic processes, which are recurrent features of the tidal forcing. Using Reynolds stresses, we reliably detected a distinct downstream mechanism where submerged groyne overflow initiates a near-bed roller and subsequent turbulent upwelling. This structure-induced transport is not just a localized anomaly. It accounts for a significant share of the inlet’s overall sediment budget and continues to drive long-term groyne-induced scour.
The study was part of the projects Gute Küste Niedersachsen, and CoastAdapt, both funded by the Niedersächsisches Ministerium für Wissenschaft und Kultur.
Link to the paper:
Herbst, M., Visscher, J., Lojek, O., & Schlurmann, T. (2026). Structure-induced turbulent upwelling and sediment mobilization in a modified tidal inlet. Continental Shelf Research, 301(105718), 105718. doi:10.1016/j.csr.2026.105718
