Flood hazards under changing climate: applying an analytical hierarchy process in the Mazam-Watrak River Basin, India

Abstract

In this study, the coupling of the analytical hierarchy process (AHP) and geographical information system (GIS) was used to assess flood hazards. Spatial analysis in the GIS environment has been applied for the estimation of flood hazard zones in which five relevant physical factors have been selected, namely rainfall amount, slope, elevation, drainage density, and land use. The factors of rainfall amount and land use are subjected to changes over a time horizon. An attempt is made in this study to delineate the flood hazard zones under changing climate, i.e., delineating flood hazard zones in base and climate change scenarios. The proposed method is applied to the Mazam-Watrak River basin in the state of Gujarat, India for the data span 1961-2016. It is concluded that flood hazard zones proliferate in the downstream and eastern middle reaches of the basin and in a very high to high category in climate change scenarios. The results obtained from the AHP have been validated through the observed flood susceptible area in the basin.