Evaluating the association of flood mapping with land use and land cover patterns in the Kosi River Basin (India)

The current study focuses on the devastating floods along the Kosi River in Bihar in July 2020, which were recorded by Sentinel-1A satellite images. Three flood-affected districts in Saharsa, Supaul, and Madhepura have been selected for this study. Pre- and post-flood images from the Sentinel-1A satellite were utilized to generate the flood-inundated map, and pre-flood Landsat-8 datasets were used to generate the land use and land cover maps. Finally, damage assessment was done by superimposing land use and land cover on a flood-inundated map. The results showed that Madhepura was the most affected district with 57.6% of its barren land experiencing inundation. Furthermore, a comparison of cloud cover percentages during the flood was undertaken using the Sentinel-1A, Sentinel-2B, and Landsat-8 datasets. The findings indicate Sentinel-1A has less than 1% cloud cover, making it suitable for flood monitoring. Due to urbanization and industrialization, land use/cover (LULC) varies rapidly, and the effect on the flood plain must be determined. TerrSet’s Land Change Modeler uses cellular automata–Markov modeling to project LULC maps for 2030 and their implications for subsequent flooding. The findings indicate that Saharsa will see an increase in the built-up area of 2.7%, Supaul with a gain of 13.4%, and Madhepura will see a growth of 10.3%. The growth of built-up regions in the near future will encourage greater impermeable layers and more discharge. Therefore, land use planners, environmentalists, and lawmakers should consider these LULC changes in water resource planning.