The Assesment of Climate Change on Run-off by SWAT Model

Increasing greenhouse gases on earth especially after the Industrial Revolution that led to sensible changes by human’s activities is called climate change. Assessment of the effects of the climate change on different parts of the water cycle for the better managing is very important. In this research, the hydrological model has been studied to assess the effects of climate change on water resources in Beheshtabad catchment. The effects of climate change are investigated in future periods. In this study, SWAT-2009 model has been used to simulate the watershed and it has calculated the amount of runoff. The results of simulation (in daily step) and existing hydrometric data have been used for calibration and validation by SUFI-2 algorithm and the 15-year period (2013-1998). The output of hydrometric stations have been used, the output of general circulation models, and LARS-WG model (HadCM3) in order to assess the effect of climate change on runoff under the climate scenarios A1B, A2 and A1B for the period (2020s), (2050s) and (2080s). The results of climate simulations have been introduced to SWAT model in change factors method. Then by re-running the model for the three above scenarios. The results showed that the annual mean temperature has been increased in the coming period in all scenarios except of B1 and runoff scenarios for the near and distant future generations get dropped. So that under the most difficult conditions the amount of runoff of Beheshtabad catchment will be decreased by 45 percent until 2100 and for the A2 scenario.