Validation of a 2-dimensional hydrodynamic model within a study to propose the optimal disposal strategy in the Western Scheldt

In order to work out a disposal strategy along sandbars in the Western Scheldt, Flanders Hydraulics Research conducted research combining field measurements and 2D high resolution numerical modelling. The Delft3D software was used for this. For the calibration of the numerical model, a lot of information and experience from previous modelling studies was available. In a first phase, the water levels in the model were calibrated by applying a space varying Manning bed roughness coefficient: in this way the propagation of the tidal wave between the different measurement stations could be adapted in the model. In a second phase, the focus of the calibration was on the flow velocities. The horizontal viscosity was used for this as the main parameter. For the intertidal area, the maps of ecotopes were used to calibrate the flow velocity. A depth depending bed roughness as well as the critical velocity between high and low dynamic intertidal areas were used for the calibration. Combining the in situ measurements, the calibrated numerical models and the experience from 2 in situ disposal tests, the engineers of Flanders Hydraulics Research succeeded in working out an optimal disposal strategy