Sediment budget for the Belgian coast: final report
Vandebroek, E.; Dan, S.; Vanlede, J.; Verwaest, T.; Mostaert, F. (2017). Sediment budget for the Belgian coast: final report. Version 2.0. FHR reports, 12_155_1. Flanders Hydraulics Research/Antea Group: Antwerp. X, 57 + 35 p. appendices pp.
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Document type: Project report
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| Keywords |
Coastal protection > Coastal protection against erosion > Morphodynamics soft coastal defences
Literature and desktop study
Transport > Sediment transport
Uncertainty
ANE, Belgium, Belgian Coast [Marine Regions]
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| Author keywords |
Sediment budget; Closure depth |
Contact detailsProposer: Vlaamse overheid; Beleidsdomein Mobiliteit en Openbare Werken; Vlaams Ministerie van Mobiliteit en Openbare Werken; Agentschap voor Maritieme Dienstverlening en Kust; Afdeling Kust , more
| Authors | | Top |
- Vandebroek, E.
- Dan, S., more
- Vanlede, J., more
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| Abstract |
In the framework of the Vlaamse Baaien project, Flanders Hydraulics Research developed a sediment budget for the nearshore Belgian coast. The study describes the sediment volumes available in the coastal system and their circulation patterns. The sediment budget equation takes into account all the sources and sinks of sediment for each of 9 longshore coastal cells, delimited based on the gradient or disruption of sediment transport. The onshore limit is usually delineated by the coastal defense structures, while the offshore limit is either the closure depth or the offshore limit of data availability. A custom tool was developed to solve the sediment budget equation for each cell. This study also estimates the uncertainties in the data and methods used. The final budget spans a ten year period, between 2000 and 2009. Most inputs to the sediment budget, such as human interventions and bathymetric and topographic data, were developed in previous studies. Other inputs, such as the closure depth, volume changes, and uncertainty of the data and methods were computed in the present study. Longshore sediment transport was calculated empirically and compared to numerical modeling results from previous studies. The latter was ultimately used in the sediment budget. The loss of sediment at the onshore boundary by aeolian transport was assumed to be very small compared to the sediment exchange at the offshore boundary. A sediment budget was built based on the change between the survey at the beginning and at the end of the considered period (2000 – 2009) considering all volume measurements, corrected and uncorrected for human interventions. However, a second sediment budget based on the linear trend was made in order to check the sensitivity of different method of calculation for the volume differences. The Belgian coast is generally balanced in terms of loss and gain of sand, with relatively little exchange to the offshore areas. The exception is in the vicinity of Zeebrugge Harbour, where large volumes of sand are exchanged with deeper offshore areas. Finally, recommendations are made about how to increase accuracy of the sediment budget in the future, including quantifying aeolian sediment transport, measuring closure depth, and extending the sediment budget to the entire Belgian shelf |
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