New method to measure dune erosion processes using a mobile, contained environment on a real beach

Master thesis (2021)

Authors

J.E. Scheijmans Civil Engineering & Geosciences

Contributors

S.G.J. Aarninkhof Hydraulic Engineering (mentor)
S. de Vries Coastal Engineering - CEG (mentor)
M.F.S. Tissier Environmental Fluid Mechanics - CEG (graduation committee member)
P.P.J. van Wiechen Coastal Engineering - CEG (graduation committee member)
Faculty
Civil Engineering & Geosciences, Civil Engineering & Geosciences
Copyright: © 2021 Jasper Scheijmans
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Published Date

01-06-2021

Language

English

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Faculty

Civil Engineering & Geosciences

Abstract

The Netherlands has 254 km of coastline that is covered with sandy dunes. As these dunes function as primary flood defences, intensive research has been conducted into dune erosion in recent years. This research mainly took place in laboratories, because all boundary conditions could be controlled and measurements could take place very accurately. However, it remains difficult to simulate a natural wave climate in a flume. In addition, there is also the risk of forgetting certain (as yet unknown) natural processes. Partly because of this, the demand for accurate field data and field measurement techniques has increased over the years. This thesis proposes a new experimental method to investigate dune erosion in the field, in which a 40 feet open-top shipping container is used as an in-field wave flume. Two containers are placed in between the low- and high waterline of the Sand Engine, near Kijkduin. The experimental method is validated by looking at the hydrodynamics within the container and by comparing dune erosion within this container with dune erosion from existing field and laboratory studies. This validation consists of four experiments in which several research hypotheses are tested to see if the wave propagation and erosion processes inside the containers work as expected. In general, it can be concluded that the experiments carried out inside the containers were in good agreement with the tested theories. These theories included that: the avalanching process is present, higher dunes have a bigger eroded volume, the dune toe follows the rising water level and the slope of the foredune remains similar during the erosion process. As this was the first time this method has been used, some recommendations are made. One of those findings is that the use of the measurement systems should be the same in both containers. A good reason to use this contained erosion method again is for the investigation of the grain size influence in erosion processes.