CHANGES IN BASIN GEOMORPHOLOGY AFTER IMPLEMENTATION OF THE OOSTERSCHELDE ESTUARY PROJECT

The completion in 1986/87 of an open storm-surge barrier in the inlet and of secondary dams in the landward parts of the Oosterschelde tidal basin (SW Netherlands) has had and will continue to have a significan t impact on geomorphological developments. An analysis of historic dat a, and of recent detailed bathymetric and morphodynamic process data, indicates that former trends have reversed. At present the Oosterschel de is a sedimentation basin with a degrading intertidal area and silti ng up of channels. The continuing reduction in intertidal area, the de creasing geomorphological gradients, the increasing fine sediment cont ent of channel deposits, combined with a general reduction in hydrodyn amics, imply significant ecological effects.