Tomohiro Suzuki, Toon Verwaest, William Veale, Koen Trouw, Marcel Zijlema


In this paper, the effect of beach nourishment on wave overtopping in shallow foreshores is investigated with the non-hydrostatic wave-flow model SWASH. Firstly, the applicability of SWASH to model wave overtopping is tested by comparing results with a physical model setup with different storm wall heights on top of an impermeable sea dike. The numerical results show good agreement with the physical model. After validation, sensitivity analysis of the effect of beach nourishment on wave overtopping is conducted by changing bottom configurations with the SWASH model. From the sensitivity analysis, it becomes clear that wave overtopping discharge in shallow foreshores is characterized by the bores generated in surf zone due to wave breaking. To reduce wave overtopping discharge in shallow foreshore, it is important to reduce the horizontal momentum of the bores.


SWASH model; beach nourishment; wave overtopping; infragravity waves; bores; shallow foreshores

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Afdeling Kust (2011). Coastal Safety Masterplan [Masterplan Kustveiligheid] [Online]. Available: http://www.kustveiligheid.be/

Baldock, T.E., Holmes, P., Horn, D.P., (1997) Low frequency swash motion induced by wave grouping. Coastal Engineering 32, 197–222.http://dx.doi.org/10.1016/S0378-3839(97)81750-4

EurOtop. (2007) Wave Overtopping of Sea Defences and Related Structures: Assessment Manual, Environment Agency UK/Expertise Netwerk Waterkeren NL/Kuratorium fur Forschung im Kusteningenieurswesen DE. 2007.

Lara, J. L., Losada, I. J., & Guanche, R. (2008). Wave interaction with low-mound breakwaters using a RANS model. Ocean Engineering 35, 1388–1400.http://dx.doi.org/10.1016/j.oceaneng.2008.05.006

Schaffer, H.A. (1993) Infragravity waves forced by short wave groups. Journal of Fluid Mechanics 247, 551–588.http://dx.doi.org/10.1017/S0022112093000564

Suzuki, T., Verwaest, T., Hassan, W., Veale, W., Reyns, J., Trouw, K., Troch, P. and Zijlema, M. (2011) The applicability of SWASH for modelling wave transformation and wave overtopping: A case study for the Flemish coast. Proceedings in ACOMEN 2011.

Troch, P., De Rouck, J. and Schuttrumpf, H. (2002) Numerical simulation of wave overtopping over a smooth impermeable sea dike. Advances in Fluid Mechanics IV, 715-724.

Van Gent, M. R. A. (1999). Physical model investigations on coastal structures with shallow foreshore: 2D model tests with single and doube-peaked wave energy spectra. WL | Delft Hydrauilcs.

Van Gent, M.R.A. (2001) Wave runup on dikes with shallow foreshores. Journal of Waterway, Port, Coastal, and Ocean Engineering, 127(5): 254–262.http://dx.doi.org/10.1061/(ASCE)0733-950X(2001)127:5(254)

Van Gent, M.R.A. and Giarrusso, C.C. (2003) Influence of low-frequency waves on wave overtopping; A study based on field measurements at the Petten Sea-defence. WL | Delft Hydrauilcs.

Veale, W., Suzuki, T., Spiesschaert, T.,Verwaest, T. and Mostaert, F. (2011). SUSCOD Pilot 1: Wenduine Wave Overtopping Scale Model: Interim Results Report. Version 2_0. WL Rapporten, WL2011R75902a_1rev2_0. Flanders Hydraulics Research.

Verwaest, T.; Van der Biest, K.; Vanpoucke, Ph.; Reyns, J.; Vanderkimpen, P.; De Vos, L.; De Rouck, J.; Mertens, T. (2009). Coastal flooding risk calculations for the Belgian coast, in: McKee Smith, J. (Ed.) Proceedings of the 31st International Conference on Coastal Engineering 2008, Hamburg, Germany, 31 August to 5 September 2008. pp. 4193-4201http://dx.doi.org/10.1142/9789814277426_0348

Zijlema, M., Stelling, G.S. and Smit P. (2011) SWASH: An operational public domain code for simulating wave fields and rapidly varied flows in coastal waters. Coastal Engineering, 58: 992-1012.http://dx.doi.org/10.1016/j.coastaleng.2011.05.015

DOI: http://dx.doi.org/10.9753/icce.v33.waves.50