Impact of climate change on droughts: a case study of the Zard River Basin in Iran

Abstract

Abstract In this research, a Soil and Water Assessment Tool (SWAT) model was assembled and used to evaluate the effects of climate change on runoff and drought in a semi-arid basin in Iran. The SWAT model showed good performance in the simulation of runoff. Eleven AOGCMs under RCP45 and RCP85 scenarios and the period 2022–2041 were selected to investigate future projections. It was predicted that runoff would decrease significantly under all scenarios. The average monthly flow at the basin outlet averaged over a year is predicted to fall from 8.75 to 6.78 m3/s over the next 20 years. In this research, the meteorological and hydrological droughts were estimated using SPI and SDI indices, respectively. By coupling climate change scenarios and SWAT models, it was found that the severity of droughts in the future will be far greater than has ever happened before.