Obtaining low water line contour value for enclave claim regime 12 nautical miles on Hatohobei Island Republic of Palau against the Republic of Indonesia in according with UNCLOS 1982 using satellite-derived bathymetry

Abstract

UNCLOS (United Nations Convention on the Law of The Sea) 1982 gives the authority to coastal state to make claims on their sea regime. An island that is more than 125 nautical miles from the mainland where the baseline to draw a territorial line is drawn is given the right to claim the maritime regime by enclave method 12 nautical miles maximum. In determining enclave claims, Low water line contour points are needed through satellite-derived bathymetry using the Lyzenga bathymetry algorithm. The data used in this study is a multispectral planet scope imagery with 3 meters resolution, where the imagery was acquired at the 07th April 2019 and depth sample from NGA nautical chart of the Hatohobei Island and Hellen reef region. To normalize the depth value, tidal correction is done by extrapolating from BIG tides data during 29 days of tides data prediction. The Lyzenga bathymetry is applied using intercept (24.422094) and the coefficient for each band result by Ordinary Least Square regression, where the R2 value obtained is 0.194075. That variable is applied in Lyzenga Bathymetry Formula. The results of the Lyzenga bathymetry algorithm are converted into contour lines to obtain low water line contour, and buffer 12 nautical miles is carried out. The result of this study shows the areas which can be claimed by Hatohobei Island (Republic of Palau). The claim of the maritime space that can be given to Tobi Island is 1634.39 km2.