Agenda for the Future – Historical evolution of tides and morphology in the Scheldt Estuary: Sub report 4. Hydrodynamic modelling of morphological scenarios

This study on historical evolution of tides and morphology in the Scheldt Estuary is part of the Agenda for the Future research program (AvdT studie: ‘historische evolutie getij en morfologie Schelde estuarium’). The general objective of this AvdT study is to improve insights on the interactions between changes in estuarine morphology and changes in estuarine tidal hydrodynamics. This subreport handles the analysis of two morphological scenarios that are simulated with the Scaldis-3D model of the Scheldt Estuary and the Belgian coastal zone. In one scenario, the 2013 bathymetry is taken as a reference and the subtidal and intertidal bathymetry are alternately adapted to the 1930 situation in four estuarine sections (Vlissingen- Hansweert, Hansweert-Liefkenshoek, Liefkenshoek-Schelle and Schelle-Dendermonde). In a second set of simulations, the 1930 bathymetry is taken as a reference and the subtidal and intertidal bathymetry are alternately changed to the 2013 situation. The goal of these scenarios is to identify the relative impact of the subtidal and intertidal morphological changes in different sections of the estuary on the global tidal hydrodynamics and point out the morphological developments leading to the largest changes in tidal hydrodynamics. Additionally, scenarios are set up in which the influence of changes in downstream forcing conditions (i.e., an increase in tidal amplitude) relative to the impact of morphological changes on tidal characteristics in the estuary is assessed.