HOW AUTONOMOUS AND ANTHROPOGENIC DEVELOPMENT OF THE SCHELDT ESTUARY (BELGIUM) AFFECT TIDAL ASYMMETRY AND SAND TRANSPORT

Abstract

A sand transport model for the Scheldt estuary was built using an existing TELEMAC-3D hydrodynamic model. The sand transport model was validated against measurements with a delft bottle at different locations along the estuary. The sand transport model was made to test different alternative bathymetries of the Upper Sea Scheldt within a large project that aims to improve the navigability of the Upper Sea Scheldt for larger ships. Within these alternative the autonomous development of the estuary by 2050 and several anthropogenic measures, like channel straightening and smoothening of sharper bends, are taken into account. The cross sectionally averaged flow velocity to the power five asymmetry between flood and ebb was used as an explanatory variable to understand better the results of the sand transport model. Changing boundary conditions, like including sea level rise, proved to play a larger role in the sand transport changes between alternatives than the bathymetric changes themselves.