Numerical Investigation on Wave-Overtopping at a Double-Dike Defence Structure in Response to Climate Change-Induced Sea Level Rise

Climate change has tremendous economic and environmental impacts on coastal areas and threatens human lives and livelihoods in generally densely populated coastal communities. Climate change-induced sea level rise (SLR) is a particular risk factor for coastal and low-lying areas. Therefore, the study on the overtopping of coastal structures in a changing climate is a critical topic for coastal protection and adaptation. As most coastal areas have shallow water conditions, the open-source nonhydrostatic shallow water equation-based model REEF3D::SFLOW is applied for the numerical investigation of overtopping over a coastal structure. Validation is performed by comparing the numerical estimations with the existing experiment presented by previous studies. The time evolution of overtopping can be predicted well by the numerical model in comparison to the experimental data. The computational speed is seen to be approximately 1500 times as fast as the Navier–Stokes equation-based counterparts. Thereafter, a comprehensive study on overtopping that takes into account different climate scenarios is presented with regard to the chosen coastal structure; this offers insights for future adaptations. The numerical approach provides an efficient alternative for the coastal protection structure adaptations in the changing climate