Flood Susceptibility Assessment in Southwest Coastal Region of Bangladesh Using an AHP-GIS Based Approach

Floods are one of the deadliest types of natural calamities that result in huge losses of lives and cause significant economic and property damages. Flood hazards are expected to persist in the future, posing severe threats to humanity. As climate change continues, the severity and frequency of floods have become a major concern in many areas of the world. Bangladesh, being located in a low-lying topography, has been facing flood disasters over the years like many other nations around the world. The country's southwest coastal region, in particular, is one of the most vulnerable to flooding. Flood management, control, and prevention measures are crucial to minimizing the likelihood of damage to agriculture, infrastructure, and other natural resources. Flood mitigation efforts and early warning systems may depend heavily on the flood vulnerability assessment. Therefore, the objective of the current study is to identify the flood susceptible zones in the six administrative districts covering Khulna, Satkhira, Pirojpur, Bagerhat, Jhalokati, and Barguna in the southwest coastal region of Bangladesh. Flood-susceptible zones are determined using a multi-criteria decision technique that has adopted an integrated geographic information system (GIS) and analytical hierarchical process (AHP)-based approach. Ten different flooding causal factors, including elevation, topographic wetness index, land use/land cover, slope, soil type, distance from the main river, surface runoff, geology, soil drainage, and soil texture, are used to identify flood susceptible zones. The flood susceptible areas with very low, low, moderate, and high risk attributes and river regions are found to be 318 km2 (2%), 1553 km2 (10%), 3556 km2 (23%), 7190 km2 (47%), and 2784 km2 (18%), respectively. It is expected that the flood-prone zones identified by this study will be used to undertake immediate countermeasures aimed at reducing flood-related losses.