GIS-based frequency ratio model for flood susceptibility zonation in the state of Meghalaya, Northeast India

The flood is the most catastrophic natural hazard accounting for the loss of life and properties. The state of Meghalaya is very diverse in its topography. The landslides hit the mountainous region, and the floods create afraid in the low-lying areas of the state every year. Although flood is a major natural hazard in the region, no major research work has been carried out yet. In the current study, a flood susceptibility zone map was prepared for the blueprint. For this purpose, ten flood triggering factors were selected for estimating the weightage through the bivariate frequency ratio model and the predictive rate of flooding, subsequently. Based on the prediction rate, it was found that LandUse/LandCover, elevation, and topographic Wetness Index had been the maximum contribution, and the Drainage Density, Distance to River minimum contribution in flood occurrences in the study area. Finally, the flood susceptibility map was generated by using the Frequency Ratio raster image and their respective predictive rate of flooding. The generated flood susceptibility zonation map was classified into five susceptibility zones. The spatial distribution of floods has been classified into a very high flood susceptibility zone covering an area of 12.06 sq. Km., the high susceptibility zone covered 0.78 sq. Km., moderate susceptibility zone covered 135.72 sq. Km., low susceptibility zone covered 22204.99 sq. Km. and the very low susceptibility zone filled 0.09 sq. Km. Subsequently, the flood susceptibility zonation was evaluated by a predicative rate and success rate curves close to 0.906 and 0.984, respectively expressed as an excellent prediction accuracy. The current research contribution will act as a blueprint and be further helpful for policymakers.