Research

Bangladesh's most frequent natural calamity, floods, are distinctive. Flood-related economic losses reduce this nation's GDP annually. Socioeconomic variables, climate change, and the country's position enhance its flood risk. The primary objective of this study is to determine the floodplain's extent based on the river's water level. This flood extent and data will generate a flood risk map to help identify the ideal sites for spatial design to mitigate flood risk. The Atrai-Karatoya river from Singra to Astomonisha was selected for this study. The preprocessed DEM was utilized to analyze catchment area whereas river water level and DEM data to identify flood inundation. LULC and flood depth maps have been used to determine the monetary damage caused by flooding in 1988, 1996, 1998, and 2016 based on the flood's magnitude. This simulated flood extent map was validated against each year's published map using a ROC curve. All curves are above the normal classifier (AUC > 0.5), suggesting all simulated models are acceptable. After generating the Depth Damage Curve and analyzing it with land use classification, the catchment area’s flood risk was calculated for 1988, 2004 & 2016. In 2020, floods damaged 732.7 million takas in the catchment region, while 1988 and 2004 flood risk damages have been adjusted to the future value of 2020. 1988's damage will be worth 2642.65 million takas, while 2004's was only 1193.4 million takas. These results indicate that the total amount of damage caused by flooding has reduced over time. This may result from the initiative taken by the GoB to adapt flood management strategies in the country over the past 50 years, which has made Bangladesh a model for reducing flood risk.