SATELLITE-BASED COMPARATIVE ASSESSMENT OF SHORELINE DYNAMICS USING DIGITAL SHORELINE ANALYSIS SYSTEM (DSAS) IN TERENGGANU AND JOHOR, PENINSULAR MALAYSIA

Abstract

The current study aims to analyse long-term coastal processes along the coast of Terengganu and Johor in Peninsular Malaysia over a 34-year period (1990–2024) with the aim of comparing two quite different coastal systems that vary in geomorphological characteristics and level of anthropogenic alteration. The eight years (1990, 1993, 1998, 2002, 2008, 2014, 2018, and 2024) were selected based on cloud-free satellite image availability and spatial consistency. DSAS is used to represent long-term shoreline change. Annual Landsat satellite remote sensing composites were examined and the shoreline was drawn using the U-Net deep learning segmentation model, with an overall accuracy of 98.7%, which provided the most robust shoreline delineations. Digital Shoreline Analysis System (DSAS) was used to measure the shoreline changes by use of Linear Regression Rate (LRR) and Net Shoreline Movement (NSM) measures. The results show that the Terengganu coast is relatively stable and shows a medium erosion and accretion due to the dynamics of the monsoonal waves in combination with the recent introduction of coastal protection structures. Johor coast, on the other hand, shows high rates of accretion due to large-scale land reclamation, estuarine sedimentation, as well as urban development, and erosion persists along the coast facing the Malacca, which experiences high wave energy.