Coastal erosion vulnerability assessment along the eastern coast of Bangladesh using geospatial techniques

Coastal zones are physically, socially, and economically important. However, many coastal zones are highly vulnerable to coastal erosion due to high population density, tourist attractions, developed economy, and lowland. Erosion vulnerability assessment with limited criteria and components cannot provide detailed and accurate results. Therefore, an integrated vulnerability assessment of coastal erosion is essential to produce detailed and accurate erosion vulnerability information to support mitigation strategies. This study aims to prepare an integrated coastal erosion vulnerability approach using geospatial techniques and examine the pattern of vulnerability to coastal erosion effects in the eastern coastal region of Bangladesh. Thirteen spatial criteria under two components of vulnerability, namely, physical and socio-economic vulnerability, were assessed. These criteria were weighted on the basis of the analytical hierarchy process (AHP) and then combined to generate individual vulnerability indices. Finally, the overall vulnerability map was produced by integrating physical and social vulnerability indices. Results showed that the area of very high vulnerability includes 11% of the region, and the area of high vulnerability was 24%. Parts of Chittagong Port, Cox's Bazar, Kutubdia, Teknaf, Ukhia, Anowara, and some portions of Moheshkhali regions close to the coastline of the study site are likely to experience high vulnerability of coastal erosion impacts. The area was classified as a low- and very-low-vulnerability zone, representing 27% and 8%, respectively. For evaluating the efficiency of the outcome, the receiver operating characteristics (ROC) technique was used to validate the physical erosion vulnerability results, which stated an 85.2% success rate and 80.1% prediction rate of the produced results. The findings can be used by concerned authorities to protect coastal erosion and minimise its effects on properties and coastal environments