Brand, E.

Chen, M.

Dan, S.

Montreuil, A.-L.

Open Marine Archive

 73 
How waves and suspended sediment affect the beach that we see 
Brand Evelien
1
, Montreuil Anne-Lise
1
, Chen Margaret
1
 and Dan Sebastian
2 
1
  VUB, Pleinlaan 2, 1050 Elsene, Belgium 
E-mail: evelien.brand@vub.be  
2
  Flanders Hydraulics Research, Berchemlei 115, 2140 Antwerpen-Borgerhout, Belgium 
 
In Belgium more than half of the coast is currently eroding and sand nourishments are carried out 
regularly. With climate change and sea level rise this will only be worse and thus coastal areas will be 
increasingly vulnerable to coastal storms and floods. To protect the beach efficiently, a good 
understanding of the beach dynamics is necessary. Therefore, the aim of this study is to relate beach 
morphological changes to hydrodynamics, such as waves and currents, and suspended sediment 
concentrations. 
 
This study was carried out at Mariakerke, close to Oostende, a managed beach characterized by 
groins, a seawall and frequent sand nourishments. More than 1.5 years of data was collected and 
analyzed. Waves, currents, and suspended sediment concentrations were measured in the nearshore 
zone at -5 and -8 m TAW. This was done at two beach sections that are one kilometer apart. At both 
sections the beach topography of three cross-shore profiles was measured every month. 
 
The results show that the beach grows when the wave height is small and the wave period is large. 
The beach erodes when the waves become steeper, i.e. have a larger height and a smaller period. 
However, when the wave height is medium, the beach erodes under small waves and grows under 
large waves. This can be related to an increase in suspended sediment concentrations when waves 
are medium. Flood dominant currents transport the sediment shoreward. For medium waves this 
results in partial compensation of erosion by waves. Thus, the beach topography is influenced by 
wave impact, but also by suspended sediment supply. 
 
Keywords: intertidal area; beach morphodynamics; wave steepness; sediment supply; coastal 
morphology  


How waves and suspended sediment affect the beach that we see

http://www.vliz.be/imisdocs/publications/311583.pdf

How waves and suspended sediment affect the beach that we see

Abstract

Similar works

Full text

Available Versions

Open Marine Archive