Changes in the normal baseline due to changes in the Coast's dynamics and Their effects on the sea boundary in Weh Island, Nanggroe Aceh Darussalam, Indonesia

Abstract

The United Nations Convention on the Law of the Sea (UNCLOS) 1982 gave archipelagic states the authority to set maritime boundaries based on such baselines. The basepoint is any point on the usual normal baseline. The base point must be established where the beach's sea level and lowest tide coincide. The location of the base point will change if the coastline's terrain or sea level changes due to physical land- and water-based causes. The reference to establish marine limits will change if the base point changes.It is possible to discover deviations from the average baseline by combining multitemporal satellite imagery with remote sensing techniques. Using satellite images, the position of the shoreline is established according to the time of image acquisition. Utilizing tidal analysis data on changes in vertical position and the slope of the coastal topography, the position of the immediate coastline is then restored to the low water line/normal baseline. Using normal baseline data, the Digital Shoreline Analysis System (DSAS) method is utilized to calculate the rate and rate of temporal changes.According to calculations of the usual baseline's speed and acceleration on the eastern portion of Weh Island, which has a Base Point (TD) of 178, the baseline has drifted 21 m seaward between 2017 and 2022, growing on average approximately 5 m per year. Consequently, coastal dynamics must be taken into account when calculating the base point if the location of TD 178 is updated in accordance with UNCLOS 1982 standards.