COASTAL SAFETY STRUCTURE PLANNING USING MODIFICATION OF ARTIFICIAL FISH APARTMENTS AT NORTH JAVA COASTAL INDONESIA

Indonesia is in the spotlight due to erosion and abrasion, especially on the North Coast of Java.The location of Tirang Beach, which is part of the North Java coast, has faced these problems for a few years.This disaster is also aggravated by the rising sea level caused by climate change.Tirang Beach area requires restoration efforts to improve the quality of life for the community.Artificial Fish Apartment (AFA) is proposed as a coastal protection alternative.This structure is designed to catch sediment, restore the marine ecosystem's habitat, and be a tourist attraction.The AFA structure will consist of concrete blocks with cavities on each side of the block.The concrete block is square and arranged stacked up to resemble a trapezoid.The modelling of hydrodynamic and sediment transport conditions using Delft3D models was carried out.Modelling is conducted for three AFA layout scenarios and compared to existing conditions.The study indicates that scenario two positively impacts the emergence of new land.The analysis shows that scenario two gets maximum sedimentation and is the most significant change for the seabed elevation change.Thus, it is predicted that reaching MSL will take approximately four years.Compared to the existing condition, the average calculated wave height reduction is approximately 0.3 m.The Analytic Hierarchy Process (AHP) method was employed to determine the best alternatives.The results indicate that scenario two is highly recommended as the top priority, followed by scenario 5 in second place.