Study on transformation and runup processes of tsunami-like wave over permeable fringing reef using a nonhydrostatic numerical wave model

Coral reefs are abundant in tropical and subtropical coastal regions. Besides their important role to ecosystems, coral reefs also act as natural buffers that help protect coastal regions from impacts of extreme surge and waves, such as those generated during hurricanes and tsunamis. Recent studies revealed that the bottom of coral reef has very similar properties as porous media. This paper investigates the hydrodynamic characteristics of the transformation and runup processes of tsunami-like wave impinging on a permeable fringing reef by applying a nonhydrostatic numerical wave model (NHWAVE). Effects of prominent factors, such as wave height, water depth, and thickness, median diameter and porosity of the permeable layer of fringing reef, on the hydrodynamic characteristics of tsunami-like wave over permeable fringing reef are discussed in detail. Results show that when the friction effects of the bottom of fringing reef are modelled using the classical quadratic friction law, the protective function of fringing reefs can be grossly underestimated. Research findings drawn from this study can further broaden our understanding on the hydrodynamic characteristics of fringing reefs under the impact of extreme surges and waves.

Automated summary

This paper investigates the hydrodynamic characteristics of the transformation and runup processes of tsunami-like wave impinging on a permeable fringing reef. It discusses the effects of factors such as wave height, water depth, and properties of the permeable layer of the reef on the hydrodynamic characteristics. The study finds that the protective function of fringing reefs may be grossly underestimated when using the classical quadratic friction law.