Modeling the morphodynamics of the mouth of the Scheldt estuary

Jebbe van der Werf, Tomas van Oyen, Bart De Maerschalck, Arnold van Rooijen, Abdel Nnafie, Marcel Taal, Toon Verwaest, Lodewijk de Vet, Julia Vroom, Mick van der Wegen

Monday 29 june 2015

16:24 - 16:36h at South America (level 0)

Themes: (T) Special session, (ST) Scheldt Estuary physics and integrated management

Parallel session: 3J. Special session: Scheldt Estuary physics and integrated management

The Scheldt estuary is situated at the border of The Netherlands and Belgium. It consists of a river part from Gent to about Antwerpen, an inner estuary (Western Scheldt) from Antwerp to Vlissingen and a mouth or ebb-tidal delta. The average Scheldt river discharge is about 100 m3/s. The pre-dominantly semi-diurnal tide amplifies in upstream direction to a tidal range exceeding 5 m near Antwerpen, making the Scheldt a tide-dominated estuary. The Western Scheldt includes the entire gradient from fresh to salt water providing various habitats for marine flora and fauna. In addition to these ecological values, the estuary is of large economic importance as it provides navigation routes to the ports of Antwerp, Gent, Terneuzen and Vlissingen. Safety against flooding is the third important aspect of the Scheldt estuary. This paper presents the Delft3D-NeVla model to study the morphodynamics of the mouth, in relation to the other parts of the Scheldt estuary. We are particularly interested in the impact of possible morphological interventions in the mouth, such as the creation of a new navigation channel and the use of this dredged sediment to protect the coast. The 2DH model covers the entire Scheldt estuary and includes the effect of tide, wind, waves, dredging and dumping activities and the presence of non-erodible layers. The model will be validated against observation data of flow, waves, suspended sediment concentration and morphological change. In this way, sand transport and morphodynamics can be predicted on a time-scale of 10-20 years.