Flooding under changing climate in Vellar river basin using global circulation models

Abstract

Flooding is one of the major natural disasters from a storm event that is prevalent in many countries and greatly affects river morphology, modifying the flora and fauna of a given river environment. As a consequence of climate change, the probability of frequent floods and drought is acute in the near future, posing serious challenges to the water management sector. This paper analyses the impact of climate change on the likelihood of floods using MIKE HYDRO river 2016 model. The model is calibrated and validated using the past flood events occurred in the years 2005, 2008, 2010 and 2011. The downscaling of weather parameters of Canadian Global Circulation Model (GCM) to the station scale is performed by Statistical Down-Scaling Model (SDSM). In the hydrological model, daily rainfall, evapotranspiration (ET0) and the atmospheric variables statistically downscaled from climate change scenarios-Representative Concentration Pathways (RCP) 4.5 and RCP 8.5 are provided as input and modifications in flood discharge are presented. It is found that there will be an increase in peak rainfall and peak discharge under the RCP 4.5 and RCP 8.5 scenarios for the future years 2050 and 2080. The changes in meteorological parameters would have a significant effect on the flow of floods since minor changes in weather pattern will greatly affect the hydrological cycle.