Impact of Climate Change on Maximum Discharges: Case Study of Aidoghmoush Basin, East Azerbaijan

Climate change has different impacts on extreme events such as flood and drought. However, in Iran there are few researches about the impacts. This research was aimed to investigate maximum annual discharge (magnitude and frequency) that may occur due to climate change in Aidoghmoush Basin during 2040-2069 (2050s). At first, monthly temperature and precipitation data of HadCM3 model under the SRES emission scenario, namely; A2, was provided for the basin. Then, these data were downscaled spatially and temporally to Aidoghmoush basin by proportional and change factor downscaling methods. Results showed that the temperature increases (between 1.5 to 4) and the precipitation varies (30 to 40 percent) in 2040-2069 compared with baseline period (1971-2000). A semi-conceptual model (IHACRES) for simulation of daily runoff was calibrated. Downscaled temperature and Precipitation for 2050s were introduced to IHACRES and daily runoff was simulated for the future. Probability distribution was fitted to maximum annual discharge series and the maximum discharge regime of the future was compared with the baseline. Results indicated that climate change affects Maximum discharge in the regime of the basin. Also, the analysis showed that the intensity of maximum discharges for the time period less than 50 does not show any significant difference; but by increasing the return period, the intensity increases in future periods. Moreover, it was shown that the probability of maximum discharges with constant intensity will decrease in the future compared to the baseline.