Multi-Temporal Analysis of Shoreline Change Using MNDWI and Landsat 8 OLI Imagery: A Case Study of Tiku Coast, West Sumatra, Indonesia

Abstract

Shoreline change caused by coastal erosion and accretion has become one of the major environmental challenges affecting the sustainability of coastal ecosystems and human activities. Tiku Coast, located in Agam Regency, West Sumatra, Indonesia, has experienced continuous shoreline dynamics influenced by marine processes and sediment transport. This study aims to identify and quantify shoreline changes between 2014 and 2024 using multi-temporal Landsat 8 OLI imagery combined with the Modified Normalized Difference Water Index (MNDWI) and the Digital Shoreline Analysis System (DSAS). Shorelines were extracted automatically from satellite imagery using the MNDWI algorithm, while shoreline displacement was evaluated through the Net Shoreline Movement (NSM) and End Point Rate (EPR) methods. A total of 336 transects were generated to assess shoreline movement along the 12.77 km coastal segment. The results indicate that accretion is generally more dominant than erosion throughout the study area. The highest accretion was observed at Transect 230 with an NSM of 71.30 m and an EPR of 7.12 m/year, whereas the most severe erosion occurred at Transect 249 with an NSM of −121.67 m and an EPR of −12.15 m/year. Temporal analysis further reveals that shoreline changes became increasingly pronounced after 2019, particularly in the western and eastern coastal sections. The integration of MNDWI and DSAS provides an efficient and reliable approach for long-term shoreline monitoring and offers valuable information to support coastal management, erosion mitigation, and sustainable spatial planning in coastal regions.