Modelling the Scheldt estuary: the 3D SCALDIS model and its applications
Vanlede, J.; Nazarali, M. (2025). Modelling the Scheldt estuary: the 3D SCALDIS model and its applications, in: Oosterlee, L. et al. Book of abstracts - ECSA Focus Meeting 2025 Estuarine Restoration: From theory to practice, University of Antwerp, Antwerp, Belgium 19-23 May 2025. pp. 88
In: Oosterlee, L.; Schoelynck, J. (Ed.) (2025). Book of abstracts - ECSA Focus Meeting 2025 Estuarine Restoration: From theory to practice, University of Antwerp, Antwerp, Belgium 19-23 May 2025. University of Antwerp: Wilrijk. 106 pp., more
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Document type: Conference paper
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| Abstract |
The SCALDIS model serves as a reference for the tidally influenced part of the Scheldt estuary and was developed using TELEMAC-3D. Initially created and calibrated for scenario analysis in the Upper Sea Scheldt as part of the "Integrated Plan of the Upper Sea Scheldt" project, it features an unstructured mesh with a higher spatial resolution, particularly upstream, compared to its predecessor, the NEVLA model which used a structured grid.
The SCALDIS model has various applications. It provides hydrodynamic input for sediment transport calculations involving sand and mud. The hydrodynamic results are used to delineate habitats in the subtidal zone of the Sea Scheldt. Specifically, the maximum flood current velocity defines boundary values for high and low dynamic subtidal zones. The SCALDIS model is also utilized to assess the impact of flood control areas on hydrodynamics in the Scheldt estuary. Tracer dispersion experiments within the model are employed to calibrate an ecosystem model. The flow fields generated by the model are processed as a flow atlas and integrated into the shipping simulator of Flanders Hydraulics.
The first SCALDIS model was calibrated for 2013, and a re-calibration was done for 2019. Flanders Hydraulics is currently developing the next model in this series, SCALDIS 2020. This update focuses on generating an optimized unstructured mesh and revising the type and location of the open sea boundary condition. All active or planned Flood Control Areas are included in the mesh of the SCALDIS 2020 model. The model is optimized for efficient computation on the High-Performance Computing (HPC) cluster of Flanders Hydraulics.
To develop a reference model with broad applicability, it is essential to implement a comprehensive calibration strategy. For this purpose, the VIMM toolbox is employed for the hydraulic model. This toolbox is internally developed at FH and operates in MATLAB. The Scheldt estuary benefits from extensive measurements, allowing for robust calibration and validation against a rich dataset. Calibration and validation are conducted for distinct, non-overlapping periods in the year 2020, encompassing storm events, normal conditions, and high river discharge scenarios in the Scheldt estuary.
Continuous water level data are available from 55 stations, while continuous salinity data are accessible from 13 stations. Additionally, continuous deep water velocity measurements for the year 2020 are recorded at two stations: Lillo and Oosterweel. Further measurement data originate from shallow water campaigns carried out over the preceding five years (2015-2020). From the sailed ADCP data, 49 campaigns were selected spanning three years before and after the modelling year (2017- 2023), ensuring an even distribution of measurements across the model domain as well as during calibration and validation phases. |
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