Flood susceptibility modelling of the Teesta River Basin through the AHP-MCDA process using GIS and remote sensing

The Lower Teesta River basin in northern Bangladesh, which is prone to recurrent annual flooding, requires refined flood susceptibility analysis. In this context, this paper presents a novel approach for quantifying flood susceptibility in the Lower Teesta River Basin through the Analytical hierarchy process (AHP) and Multi-criteria decision analysis (MCDA) using geographic information system (GIS) and remote sensing techniques. Ten flood conditioning parameters were selected for flood susceptibility modelling, based on a comprehensive literature review and expert opinion. These parameters include the topographic wetness index (TWI), elevation, slope, rainfall, proximity to rivers and roads, soil type, drainage density, land use and land cover type, and the normalised difference vegetation index (NDVI). This comprehensive assessment resulted in the creation of an exact flood risk map that delineates areas within the basin that are prone to high or very high flood risk. The model was subjected to rigorous validation using ROC-AUC analysis, yielding an impressive AUC score of 0.848, underscoring its robust predictive capabilities. These results highlight the importance of continued monitoring and targeted flood risk reduction measures in this region, particularly in high-risk areas. Although the study was conducted on a regional scale, it has a broad readership appeal and impact that extends beyond the region. The approach employed in this study is transferable to a range of environmental settings, both within Bangladesh and globally.