Morphodynamic modelling of the Belgian Coastal zone: Sub report 1 – Scaldis-Coast progress report 1
Kolokythas, G.; Wang, L.; Breugem, A.; De Maerschalck, B. (2024). Morphodynamic modelling of the Belgian Coastal zone: Sub report 1 – Scaldis-Coast progress report 1. Version 4.0. FHR reports, 21_104_1. Flanders Hydraulics: Antwerp. VI, 34 p. pp.
Part of: FHR reports. Flanders Hydraulics Research: Antwerp, more
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Document type: Project report
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| Authors | | Top |
- Kolokythas, G., more
- Wang, L., more
- Breugem, A.
- De Maerschalck, B., more
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| Abstract |
Within the current project the Scaldis-Coast model will be updated, further developed and improved. The presented report is the first progress report on the progression made in the first year. The model has been updated and tested with the new TELAMAC-MASCARET v8p3 release with a new sedimenttransportand bed-update module called GAJA, replacing the previous SYSIPHE module. It was found that the update of the model with the new release didn’t have any significant impact on the model results. Only at the northern boundary some unrealistic sedimentation patterns where observed after the update, which require more investigation and probably a bug fixing or work around. However, this local sedimentation is far outside the domain of interest and has no significant influence on the bed evolution of the Belgian coast.
Furthermore, efforts have been taken in improving the Bijker sediment transport formula used in the model. It was observed than when the model was used for some extreme sea level rise scenarios some unexpected strong cross-shore transport occurred, nevertheless cross-shore processes are not included in the model yet. Based on an extensive set of model tests, two modification of the formulations showed some major improvements of the model behaviour:
• Replacement of the default wave-current bed shear stress formula in Bijker’s transport formula with the τcw formula proposed by Soulsby (1995), known as the DATA2 method and based on a fit to laboratory and field measurements
• Replacement of the default (fixed) breaking wave parameter (b) in in Bijker’s transport formula with a spatial-temporal varying expression that depends on the wave height and water depth ratio (Bijker, 1971).
Two other improvements, but with less impact have been implemented as well:
• Use of the formula for deviation (correction of sediment transport direction due to slope effect) by Talmon et al. (1995) instead of the default one (Koch and Flokstra , 1981)
• Minimum depth for bed load equal to 0.1 m (instead of 0.01 m)
The findings mentioned above were confirmed through a series of applications, which included: (a) the calculation of the annual longshore transport volumes along the Belgian coast and (b) a storm event (Ciara) in February 2020 with important impact at the marina of Blankenberge (c) a long-term morphological hindcasting (years 1986-1996) at the area east of Zeebrugge port related to the extension of the port which was completed in 1986. |
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