Flood Inundation Mapping by Multi-criteria Decision Analysis—A Study on Recent Floods—Idukki District, Kerala-India

Flood is one of the natural disasters that affects the lives and property of people. Faster urbanization and changes in climate have made high chances for floods. It is not possible to prevent floods, but they can be managed through suitable flood susceptibility maps. This study examines the Land Use Land Cover (LULC) changes for the years 2013, 2018, and 2024, and its impact on flood is studied for the Idukki district in Kerala. The flood susceptibility map is generated based on the multi-criteria decision process. A total of seven flood impact factors, such as elevation, slope, geology, drainage density, stream to road network, soil, and LULC factors, are counted for generating the flood susceptibility maps in Idukki district. A notable increase in flood depth and spread is observed during the years 2013 to 2024 in the study area. The susceptibility maps characterized the flood from a very high flood zone to a very low zone. The validation of the MCD analysis is compared with historical flood locations that are susceptible to flooding. The accuracy of the generated map is 85% which shows the precision of the model developed. The flood map produced will identify the areas that are susceptible to high and low floods in the Idukki district. The study also infers about the LULC changes and their effect on the flood.