Coastal Vulnerability Assessment Based on Multiple Bio-Geophysical Hazards: A Case Study in La Union, Philippines

Abstract This study focuses on the coastal vulnerability of La Union, Philippines, a province located along the western coastline in the northern island of the country. Using the Coastal Vulnerability Model in the Integrated Valuation of Ecosystem Services and Trade-Offs (InVEST), the research assesses the spatial distribution of exposure to flooding and inundation due to extreme weather events in La Union. The results reveal varying levels of vulnerability, with a substantial proportion of the coastline categorized as very low to low exposure. However, moderate and high exposure areas are also identified, indicating specific locations with heightened risks. Two scenarios, (i) with and (ii) without natural habitats, are compared to quantify the influence of habitats on coastal vulnerability. The study emphasizes the importance of natural habitats, such as mangroves, in providing coastal protection. Moreover, the need for targeted interventions, adaptive management, and sustainable development practices to mitigate climate change’s impacts and protect coastal communities and ecosystems in La Union, Philippines, is being highlighted as an important strategy to enhance resilience against natural coastal hazards. This is the first study that employs the InVEST suite of models in assessing coastal vulnerabilities in the Philippines.