Graduation of Roy van Weerdenburg

28 January 2019 15:00 - Location: Lecture Room G, Faculty of Civil Engineering and Geosciences - By: Webredactie

"Exploring the relative importance of wind for exchange processes around a tidal inlet system: the case of Ameland Inlet." | Professor of graduation: Prof. dr. ir. Z.B. Wang (TU Delft / Deltares), supervisors: dr.ir. B.C. van Prooijen (TU Delft), ir. P.K. Tonnon (Deltares), ir. S.G. Pearson (TU Delft / Deltares), dr. M.F.S. Tissier (TU Delft).

Considering scenarios of sea level rise, the sediment budget of the Wadden Sea is of interest for both coastal safety and the values of this unique environment. Sand nourishments are foreseen at the ebb-tidal deltas of the Wadden Sea to increase the sediment budget, which requires us to predict the fate of the nourishment. In this study we are interested in the exchange of water and sediment between the North Sea and the Wadden Sea through Ameland Inlet. Based on a combination of field observations from the extensive 40-days Kustgenese2.0/SEAWAD field campaign in fall 2017 and Delft3D modelling results the flow conditions are explained and the contribution of different forcing mechanisms is unravelled. Residual flow and sediment transport at the ebb-tidal delta were found nonstationary due to the action of waves, but also due to local wind-shear stresses. The spatially varying contribution of wind forcing is presented based on modelling results. The wind-driven exchange with neighbouring basins over the tidal watersheds leads to a significant residual outflow through Ameland Inlet, which increases the importance of wind for the system functioning. The many shallow areas and the orientation of the system in relation to the prevailing wind direction for strong winds are believed to make wind forcing as important as observed around Ameland Inlet.