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Dune safety in Callantsoog : the dune safety development due to sand nourishments, since 2000 in Callantsoog, the Netherlands.

Hageman, E.M. (2018) Dune safety in Callantsoog : the dune safety development due to sand nourishments, since 2000 in Callantsoog, the Netherlands.

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Abstract:In this thesis, the effect on the dune safety in the area of Callantsoog, due to the nourishment executed since the year 2000, are analyzed. The focus of dune safety is on the erosion volume and the erosion profile after a 1/3000-year storm. Firstly, the volume increase and profile change of a number of coastal cross sections are analyzed. Since the year 2000, 8 nourishments are executed in the research area. Because of those nourishments, the dune and beach volume increased. Also because of the nourishments, changes occurred in the nearshore bathymetry data, which affects the wave energy reaching the dunes. The changes that the bathymetry underwent, caused less wave energy to reach the dune, so less erosion takes places during the surge storm. This change is confirmed by obtained post-storm dune foot of the past 18 years. Two models are used to determine the dune safety. A distinction is made in an empirical dune erosion model, DUROS+, and a process-based model, XBeach 1D. At the moment the empirical model is the official model used by Rijkswaterstaat to assess the Dutch coastal primary barriers. It appears that the empirical model gives about double as much erosion volume compared to the process-based model. Before implementing the XBeach 1D model as official assessment tool of the Dutch coastal primary water barrier, it is suggested that some extra research has to executed. The comparison in the models is made, since a pilot nourishment is executed at a depth of -10m NAP in the year 2017. This depth is not taken into account in the empirical model. But the question is, if this deep shoreface nourishment does have influence on the dune safety. However, it seems that a nourishment at this depth, and even significantly higher, does not have noteworthy changes on the erosion volume and erosion profile at this moment.
Item Type:Essay (Bachelor)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering BSc (56952)
Link to this item:https://purl.utwente.nl/essays/75469
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