Evaluation of the climate change effect on Babol-rood watershed runoff using IHACRES model

Babolroud watershed in Mazandaran province in recent years experienced different climate events. On this basis¡ emphasize necessity to investigate further on impact of climate change on watershed runoff. This work is done by climate change models that able to simulate climatic variables. Due to the forecast lack of meteorological parameters in the point scale by climate change models¡ weather generator tool interface was developed by which it can be evaluated climate change in point scale and the desired station. In this study¡ using this method¡ the data model HadCM3 general circulation of the atmosphere with the use of LARS-WG software according to A2¡ B1 and A1B three scenarios for first time periods (2046-2065) and second (2080-2099) were. The results revealed that change in rainfall in Babul-rod watershed varies between -43% to %. This variation ranges accompany with rainfall increase in rainy months and severe decrease in months with low rain¡ respectively. Also¡ Increase in annual temperature in average was 1.4c to 3.6c¡ especially in warm months. After this step the values of temperature and precipitation predicted by the HadCm3 climate model introduced to IHACRES rainfallrunoff model and changes in discharge determined in both the first and second periods¡ respectively. Average monthly flow( ) in the base period (17.42) was higher than the average of the first period (14.82) and the average of the second period (14.20) which it refers to reduction of 15 to 18.5 percent the average monthly runoff. According to the study¡ rising temperatures and reduced rainfall throughout the coming years lead to reduce runoff and water resources due to more evaporation and aridity will watershed that consequently affects the climate of the region in the near future¡ the number and intensity of floods and droughts will increase.