Detached Hexareef Breakwater Configuration Design to Reduce the Effect of Ocean Waves at Eco-Resort Area Raja Ampat

The Eco-Resort area at Raja Ampat is frequently impacted by extreme waves, particularly during the west monsoon, increasing the risk of abrasion and damage to ecosystems and infrastructure. A detached hexareef breakwater configuration was designed to reduce wave height while maintaining coastal aesthetics, as the site is an eco-friendly tourism area. The data used included tidal observations, bathymetry and topography surveys, wind and wave data, and hexareef formation data. The configuration was designed based on the beach response index, leading to periodic tombolo formation. Four configuration alternatives were developed based on freeboard (f) values under the HWS (Highest Water Springs) condition. Numerical modeling using Delft3D-WAVE assessed wave reduction effectiveness for each alternative. Results showed wave reductions for two significant wind and wave directions - North and Northwest - as follows: 24% and 33% for Alternative 1 (f = -1.018 m), 46% and 55% for Alternative 2 (f = -0.518 m), 66% and 71% for Alternative 3 (f = -0.218 m), and 72% and 77% for Alternative 4 (f = -0.018 m). Alternative 3 was chosen because its performance was only 6% lower than Alternative 4 (the most effective); however, it has a submergence value that is more suitable for maintaining coastal aesthetics.