Document of bibliographic reference 251102

BibliographicReference record

Type

Bibliographic resource

Type of document

Reports

Type of document

Project report

BibLvlCode

MS

Title

Scientific support regarding hydrodynamics and sand transport in the coastal zone: hindcast of the morphological impact of the 5-6 December 2013 storm using XBeach

Abstract

A storm occurred in the North Sea on 5-6 December 2013 (also known as the Sinterklaasstorm) which generated high surge levels and moderately high wave heights along the Belgian coast, resulting in beach and dune erosion. Measurements of beach profile change along 122 cross-shore survey transects were compared with the numerical model XBeach. First, a novel configuration for XBeach was developed that takes into account the effects of wave directional spreading since XBeach cannot resolve directionally spreading of long waves in 1D mode (which is generally used to predict cross-shore profile change). The effect of wave directional spreading on hydrodynamics and sediment transport is investigated using idealized and realistic simulations. Idealized simulations show that the near-shore long wave field is more energetic in 1D than in an equivalent 2D model with an alongshore-uniform bathymetry. Realistic storm scenarios show that this leads to predicted erosion volumes that are 25-57% higher than in the 2D model. Sparse 2D models with 5 to 8 alongshore grid cells provide a reasonable approximation (both for hydrodynamics and sediment transport) of the full 2D model (with 50 alongshore grid cells) at a lower computational cost. The December 2013 storm was therefore simulated using a sparse 2D model with 5 grid cells in the alongshore direction. Good agreement with measured erosion volumes was found when using a recently established set of calibration values provided by Deltares. Default calibration values from an older version of XBeach lead to an overestimation of the erosion volumes, as does the use of a 1D model instead of a sparse 2D model. The sensitivity of the predicted erosion volumes to increased surge levels and wave heights was also investigated.

Bibliographic citation

Lanckriet, T.; Trouw, K.; Zimmermann, N.; Wang, L.; De Maerschalck, B.; Delgado, R.; Verwaest, T.; Mostaert, F. (2015). Scientific support regarding hydrodynamics and sand transport in the coastal zone: hindcast of the morphological impact of the 5-6 December 2013 storm using XBeach. Version 4.0. WL Rapporten, 12_107. Flanders Hydraulics Research/IMDC: Antwerp. III, 36 + 65 p. appendices pp.

Topic

Marine

Access rights

open access

Is accessible for free

true