Assessment and Evaluation of Flood Vulnerability of Chhota Udepur District, Gujarat, India Using Analytical Hierarchy Process: A Case Study

Chhota Udepur district of Gujarat, India often receives floods during monsoon, which potentially affects socio-economic conditions. A flood vulnerability map serves as an important tool for flood modelling to manage and minimize the impacts of floods. This study employs a Multi-Criteria Data Analysis (MCDA) approach in conjunction with an Analytical Hierarchy Process (AHP) and GIS to model flood events. Identification of flood-vulnerable zones was conducted using the AHP with the help of fifteen flood-affecting parameters including precipitation, slope, elevation, curvature, topographic wetness index (TWI), drainage density, topographic ruggedness index (TRI), distance from the river, land use land cover (LULC), soil-adjusted vegetation index (SAVI), normalized difference vegetation index (NDVI), stream power index (SPI), soil texture, geology, and geomorphology. The flood causative factors were estimated to determine the weightage of factors for the preparation of the flood vulnerability map. Results revealed that flood occurrence in the district is highly dependent on precipitation and LULC. More than 22% of the total geographical area comprising about 764 km² was observed under a high flood vulnerability zone and about 69% under a moderately flood vulnerable zone. Mostly, Sankheda and Naswadi taluka were found to be highly vulnerable to flooding. The flood zonation maps generated during this investigation could facilitate managing the flood conditions in the district.