3. Flood Susceptibility Mapping Using Microwave Sentinel-1A Data and Analytical Hierarchy Process (AHP) in Lowland Area of Keleghai River Basin

Climate change is leading to extreme precipitation, which is associated with the most severe hazardous floods in the world. Therefore, producing susceptibility maps for controlling floodplains is most important to reduce its harmful effects on development purposes in local level. This chapter aimed to prepare the flood susceptibility regions based on the Analytical Hierarchy Process (AHP) integrating eight susceptibility factors such as elevation, slope, drainage density, distance to river, rainfall, Normalized Difference Vegetation Index (NDVI), Land Use Land Cover (LULC), and soil respectively. On the other hand, Sentinel-1A Synthetic Aperture Radar (SAR) data was applied to delineate the flood inundation and inventory area which experienced flooding in 2021 with integration of geospatial techniques in lowland area of the Keleghai river basin. The delineated flood susceptibility map was generated five susceptibility classes: very low, low, moderate, high, and very high respectively. The AHP model reveals that 16 and 2% of the area in the study area is under the high and very high flood susceptibility zone. The Area under Curve (AUC) in Receiver Operating Characteristics (ROC) was used to evaluate the accuracy and validate the model. In the AHP model, the AUC was recorded 0.85 which is significantly excellent accuracy for the flood susceptibility mapping. These findings can help identify better land use planning and would assist researchers, hydrologists, policymakers, and local governments in flood risk management.