Perpustakaan Digital ITB

Human activities in coastal areas will generally lead to a greater rate of erosion and tidal flooding due to the loss of natural protection in the form of mangrove or inappropriate structures in coastal areas. Dadap Beach, located in Juntinyuat District, Indramayu Regency, West Java Province is one of the locations experiencing problems above. In 2003, a Fishing Port (PPI) was built on Dadap Beach with structure that jutted into the sea 200 m from the shoreline. This port structure is designed to prevent sedimententation from the longshore sediment transport, but currently there has been a massive sediment depositionin the port pool area, and a tombolo is formed behind the port structure. The existence of this tombolo disturbs the balance of sediment transport in the coastal area around the port, so that in recent years the rate of coastal erosion has increased significantly and threatens rice fields and settlements. Furthermore, to overcome the coastal erosion, BBWS Cimanuk-Cisanggarung has built a coastal protection structure in form of an offshore breakwater. This study aims to analyze the hydromorphologycal effect of port structure and coastal protection at Dadap Beach, Juntinyuat District, Indramayu Regency at the surrounding coastal area, using a numerical model simulation (Delft 3D). The simulation results show that the existence of the port structure and coastal protection at Dadap Beach causes changes in current patterns due to wave diffraction by the port structure, which causes a significant decrease in longshore current velocity behind the structure and interrupting the longshore sediment transport balance. The results of this study are expected to provide a reference regarding the effect of coastal structures located in shallow water areas on currents pattern and sediment transport, so that the negative impacts of these structures can be anticipated properly.