Coastal Vulnerability Assessment using AHP and Weighted Linear Combination: A Case Study of Subang Regency in Indonesia

Coastal regions along the northern coast of Java are increasingly vulnerable to shoreline retreat, tidal inundation, ecosystem degradation, and socioeconomic pressure driven by climate change and anthropogenic activities. This study evaluated coastal vulnerability along the coast of Subang Regency, Indonesia, using a multidimensional Coastal Vulnerability Index (CVI) framework that integrates indicators of physical, environmental, exposure, and adaptive capacity. The study used a geographic information system (GIS)-based multicriteria approach using fourteen vulnerability parameters derived from remote sensing analysis, unmanned aerial vehicle surveys, field observations, institutional datasets, and stakeholder assessments. Parameter weighting was conducted using the Analytic Hierarchy Process integrated within a weighted linear combination framework and compared with the conventional geometric CVI method. The results revealed substantial spatial variability among the four coastal sub-districts. Legonkulon showed the highest vulnerability level, followed by Blanakan, Sukasari, and Pusakanagara. Adaptation capacity, green-belt width, shoreline change, and population density within hazard-prone zones were identified as the most influential vulnerability parameters. The weighted framework provided flexibility in representing the interactions between physical susceptibility and socioeconomic resilience. Therefore, integrating environmental and adaptive-capacity indicators within a GIS-based multicriteria framework can support operational coastal vulnerability assessments and regional adaptation planning in rapidly changing tropical coastal environments.