|Modelling of suspended cohesive sediment transport in the De IJzermonding estuary using TELEMAC-2D and SISYPHE|
Xinyao, Y. (2005). Modelling of suspended cohesive sediment transport in the De IJzermonding estuary using TELEMAC-2D and SISYPHE. MSc Thesis. Katholieke Universiteit Leuven (KUL)/Vrije Universiteit Brussel: Brussel. ix, 84 pp.
Cohesive sediments; Modelling; Sediment transport; Tidal environment; ANE, Belgium, IJzer R. [Marine Regions]; Marine
Understanding the transport processes of cohesive sediments in tidal estuaries is of great significance for estuarine environmental management. This study forms part of an investigation of the sediment dynamics in the IJzer Estuary.
A literature survey is performed first on the current knowledge of the three most important morphodynamic processes: erosion, deposition and transport. The knowledge gained from the literatures forms the basis of data interpretation and analysis of model results in the following chapters.
This work is a continuation of the work done by Nolivos and Choudhury (2004). They set up a two dimensional vertically averaged hydrodynamic model using the TELEMAC software package. In this work, the model domain has been extended northward into the North Sea and southward to the lock system that most of time seals the estuary from the IJzer River. GIS has been used to merge the elevation data from different parts of the IJzer Estuary. Dry elements in the domain have been eliminated in STBTEL to guarantee the accuracy in results. In a next step a model has been set up to simulate the transport of suspended cohesive sediment using the SISYPHE package in TELEMAC. Imposing the concentration data on the open boundary is an important step, as it makes it possible to model the inflow of sediment from the North Sea. A routine has been programmed in order to read and assign the concentration data to the boundary nodes, and to prescribe the thresholds for erosion and deposition.
One day simulation has been executed to validate the previous hydrodynamic model and to calibrate the sediment transport model. However, due to a difference in measurement location and placement of the open boundary in the numerical model, the sediment transport cannot be well calibrated. Next, three scenarios have been designed, respectively for suspended load of pure mud, bed load of sand-mud mixture and total load of sand-mud mixture. A strip of about 750m long in the junction of the navigation channel with the tidal flat is identified as main erosion area while the two harbors, the mudflat and the tributary are deposition zones. In this case study, transport of suspended load has major impacts on the bed morphology. Finally, some encountered limitations of the TELEMAC software are also discussed.