Development of a mud transport model for the Scheldt estuary

A mud transport model for the Scheldt estuary is being developed. Its purpose is to support managers of the Scheldt estuary with the solution of a number of managerial issues. The model domain ranges from the tidal boundary at Gent down to the Belgian coastal cities of Nieuwpoort and Zeebrugge.The hydrodynamic simulations on which the mud transport model is based show realistic values for water levels, salinities and residual currents in the major part of the model domain. However, the propagation of the tidal wave is modelled less accurately upstream of Antwerp.Regarding the mud transport simulations, which are based on simple process formulations, it is shown that a satisfactory agreement is obtained between computed and observed concentration levels and their spatial and temporal variations. SPM levels in the Scheldt appear to be rather sensitive to the volume of harbour siltation and dumping, notably near Antwerp.The sediment budget computed by the model includes an unrealistically high residual sediment flux towards the North Sea. By enhancing the estuarine mud circulation, the modelled residual flux becomes smaller and agrees better with observation-based estimates. A longer hydrodynamic simulation period (presently up to 3 months) would help to analyse the sediment budget and seasonal dynamics in more detail.

Research highlights
► Development of process-based numerical model for long-term and large-scale mud dynamics.
► Model computes both (dynamic) equilibrium bed composition and SPM levels.
► Satisfactory comparison with field data regarding mud distribution in water column and at bed.
► Computation of mud balance and influence of different forcing factors hereon.