Investigation of the effect of different coastal dam types on wave overtopping

Climate change has significantly exacerbated coastal erosion. Thus, implementing coastal dams is crucial in reducing wave overtopping and mitigating the effects of climate change. The three commonly used coastal dam structures are vertical seawalls, curved seawalls, and riprap dams. Along with these, we designed three more dam models (triangular, zigzag, and inverted triangle) for this investigation, possessing characteristics similar to those as mentioned earlier commonly used dams. Through this research, we used such physical models to understand how different dam designs affect seawater overtopping by creating in-phase waves or redirecting wave impact and diffusing wave energy. We used compressed foam models to simulate wave impacts in a wave tank across 6 different wave frequencies to analyse which dam designs are most suitable in preventing the overtopping of seawater at coastal areas through the smallest maximum vertical displacements of water, concluding that the inverted dam is the most effective in reducing overtopping due to the redirection of wave energy downwards, followed by the zigzag dam, vertical seawall, riprap dam and curved seawall. The inverted dam is the most effective in reducing overtopping due to its narrow bottom lacking outward protrusion and redirection of wave energy downwards, followed by the zigzag dam, vertical seawall, riprap dam and curved seawall. The triangular dam, which was used as the control, was the least effective model due to the upward reflection of wave energy. To reduce overtopping in real life, a parapet can be attracted onto existing dams to redirect water downwards.