Optimal design and placement of a combined trench and submerged breakwater system on the coastal area of Aceh

Tsunami waves are currently one of the most devastating water hazards that threaten regions or countries near the subduction zones, including Indonesia. In this research, a novel coastal protection system combining a submerged breakwater and a trench is proposed to mitigate the tsunami occurrences. The model is developed based on the Shallow Water Equations, which is then solved analytically using the Separation Variables Method, and numerical using the Staggered Finite Volume Method. Wave transmission coefficient, which indicates the wave reduction rate generated by the system, is expected to be the outcomes of both approaches. The numerical scheme is validated against the analytical solutions to verify its accuracy in estimating wave reduction by the system. Further, an optimization technique is integrated to the model to obtain the optimal size and position of each structure (submerged breakwater and trench), on the real bathymetry of Aceh's coastal, which has been impacted by a deadly tsunami occurrence before. The results of this study is expected to be useful in the future development of coastal protection system against tsunami waves, especially in Indonesia.