How to Cite

Elghandour, A., Roelvink, D., Huisman, B., Reyns, J., Costas, S., & Nienhuis, J. (2020). REDUCED COMPLEXITY MODELING OF SHORELINE RESPONSE BEHIND OFFSHORE BREAKWATERS. Coastal Engineering Proceedings, (36v), papers.34.


Prediction of the shoreline response behind offshore breakwaters is essential for coastal protection projects. Due to the complexity of the processes behind the breakwaters (e.g., wave diffraction, currents, longshore transport), detailed modelling needs high computational efforts. Therefore, simplifying the process effect in a simpler coastline model could be efficient. In this study, the coastline evolution model ShorelineS is used. A new routine was implemented in the model to adjust the wave heights and angles behind the offshore breakwaters. Two approaches from the literature and a newly introduced one were tested in this study. The model free grid system was used to simply track the breaker line; such an advantage also helped to form tombolo, which is not common for these types of models. The tests showed promising results for single and multi breakwaters systems; however, the newly introduced approach still needs further testing and refinement for better performance and less computational cost.

Recorded Presentation from the vICCE (YouTube Link):


Dabees, M. (2000). Efficient modeling of beach evolution. Ph.D. Thesis. Civil engineering, Queen´'s University, Kingston, Ontario, Canada.

Deltares. (2011). UNIBEST-CL+ Manual : Manual for version 7.1 of the shoreline model UNIBEST-CL+.

Elghandour, A. M. (2018). Efficient Modelling of coastal evolution Development, verification and validation of ShorelineS model. IHE Delft Insitute for Water Education, Delft, The Netherlands.

Hanson, H., & Kraus, N. C. (1990). Shoreline response to a single transmissive detached breakwater. Coastal Engineering Proceedings, 1(22), 2034–2046.

Hanson, H., Larson, M., Kraus, N. C., & Gravens, M. (2006). Shoreline response to detached breakwaters and tidal current comparison of numerical and physical models. In Coastal Engineering Proceedings (pp. 3630–3642).

Heerdink, J. (2003). Shoreline response to offshore breakwaters. TU Delft. Retrieved from

Hsu, J., & Silvester, R. (1990). Accretion behind single offshore breakwater. Journal of Waterway, Port, Coastal, and Ocean Engineering, 116(3), 362–380.

Hurst, M. D., Barkwith, A., Ellis, M. A., Thomas, C. W., & Murray, A. B. (2015). Exploring the sensitivities of crenulate bay shorelines to wave climates using a new vector-based one-line model. Journal of Geophysical Research F: Earth Surface, 120(12), 2586–2608.

Kamphuis, J. W. (1991). Alongshore sediment transport rate. Journal of Waterway, Port, Coastal, and Ocean Engineering, 117(6), 624–640.

Khuong, T. C. (2016). Shoreline response to detached breakwaters in prototype. Delft University of Technology.

Roelvink, D., Huisman, B., Elghandour, A., Ghonim, M., & Reyns, J. (2020). Efficient modeling of complex sandy coastal evolution at monthly to century time scales. Frontiers in Marine Science, 7, 535.

Suh, K., & Dalrymple, R. a. (1987). Offshore Breakwaters in Laboratory and Field. Journal of Waterway, Port, Coastal, and Ocean Engineering, 113(2), 105–121.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.