Simulation of Climate Change on river Hydrograph Using WetSpa Model, Case Study: Taleghan Watershed Alborz Province

One of the major issues in hydrology engineering is the prediction of the flood routing or rising and falling limb river hydrograph, in which the importance of the climate is very evident due to the high volatility and is therefore one of the most important factors to be carefully studied. The main objective of this research is to investigate the past and future potential of climate change and its impacts on the hydrologic response of the basin. In this study, the Taleghan watershed of the Sefidrood basin was selected as a case study due to its socio-economic significance. At first using weather data and meteorological data with a daily step in a 21-year period and three base maps information, flow hydrograph was simulated using WetSpa model in Taleghan watershed. Results show that there is good agreement between simulation and observations in the base period. Then, the future climate change (precipitation, temperature and evaporation) based on CanESM2 model from the fifth report the Intergovernmental Panel on Climate Change (IPCC) on emission scenario RCP8.5 was used for simulating the flow hydrograph during the next period (2016-2029) and its comparison with the base period (1995-2015). The results showed that in the considered scenario, the average runoff watershed will increase Up to 45% by the climate in the future. Also, the average of runoff will increase in all months of the year (except in October) compared to the base period. This increase is more pronounced for April.