Ebb-tidal delta morphology in response to a storm surge barrier

The Eastern Scheldt ebb-tidal delta morphology has been adapting for the past 25 years in response to the construction of the Eastern Scheldt storm-surge barrier in 1986. As a result of the barrier, there has been a decrease in tidal amplitudes, volumes, and average flow velocities, and there is hardly any sediment exchange through the barrier. Bathymetrical measurements of the ebb-tidal delta show multiple effects: (1) an overall decrease in sediment volume, (2) a decrease in morphological activity, (3) sedimentation in most channels, (4) northward reorientation of channels and shoals, and (5) an increase in wave-driven features. Some channels are showing stronger erosion since 1986. This, and the reorientation of other channels could be related to changes in the interaction between crossshore and alongshore tide. Most of the erosion is located in shallower, wave-dominated regions, indicating that waves have become relatively stronger. The steady erosive trend, combined with the decline of morphological activity, points toward a system dominated by relatively small and mostly negative bed-level changes. This system is still far from any kind of equilibrium, and is steadfastly adapting itself to the new hydraulic forcing regime, even though sediment transport capaci ies have decreased