Flood risk index mapping in data scarce region by considering GIS and MCDA (FRI mapping in data scarce region by considering GIS and MCDA)

Climate change is responsible for triggering one of the most destructive natural disasters known as flooding. The flood risk index quantifies the vulnerability of an area to flooding, providing valuable insights for mitigation and preparedness efforts. Flood risk index integrates factors, aiding understanding and fostering resilient communities. This study uses an integrated strategy of geospatial technology and multi-criteria decision analysis to produce a map of the flood risk index for a data scarce region. Through this research work, fifteen thematic maps (i.e., Lithology, Soil, Slope, Drainage Density, Land use and Land cover, Rainfall, Distance from river, Permeability, Runoff, Normalized Difference Vegetation Index, Normalized Difference Built-up Index, Modified Normalized Difference Water Index, Topographic Wetness Index, Profile and Plan Curvature) in case of flood hazard index and three thematic maps (i.e., Population density, Crop production and Road river interaction) in case of flood vulnerability index were used. Thematic maps checked for multicollinearity, overlaid in ArcGIS with ranked assignments using AHP to develop flood hazard and vulnerability maps. The flood risk map was developed by integrating the flood hazard and vulnerability maps. The research region divided into five categories based on flood risk index map: very low (8%), low (28%), moderate (16%), high (20%), and very high (28%). The regions such as Vangara, Pathapatnam, Tekkali, Kusumala, Ichapuram shows very high tendency towards flood risk. This was due to favorable factors such as high/ moderate runoff, slope (very gentle/ gentle), very low/ low permeability, lithology (granite/ gneiss) etc. of the research region.