Journal of Watershed Management Research

  Concern about the impact of climate change on natural and socioeconomic systems has been increased in recent years and this issue caused an increasing interest in the scientific community . The aim of this study is to evaluate changes in parameters such as precipitation, minimum and maximum temperature by General Circulation Models (GCM) and its impact on average runoff using SWAT model in Ghazaghli watershed in Golestan province. Initially, these parameters based on IPCC scenario A2 and B1 and using HadCM3 of general circulation models and for future periods 2030-2011 and 2099-2080 using LARS-WG weather generator in the synthetic was simulations and downs scaling. To investigate the basin hydrological response with changes in climate input data to the optimized SWAT rainfall - runoff model, after run model output of model was evaluated. The results showed that in the study area, the average minimum and maximum temperatures in both the period and the second period would increase under both scenarios. Rainfall increases in all months in the period 2030-2011 while in the period 2099-2080 the precipitation will increase in the cold season. Runoff analysis shows that under both scenarios A2 and B1 in the future compared to the baseline scenario (period 1995-1985) runoff between the 133.28_-26.66 percent will change to several month. Compare scenarios A2 and B1 show that B1 scenario compared to A2 scenario and 2099-2080 periods compared to 2030-2011 periods in the study area have critical condition.