ASSESSMENT OF CLIMATE CHANGE IMPACTS ON INFLOW TO THE KARAJ DAM (CASE STUDY: IRAN, KARAJ DAM)

Abstract. In this study, the role of climate change and its impacts on temperature and precipitation in the future period on the inflow to the Karaj Dam was evaluated using the LSTM and LSTM-FHO simulation methods. Inflow data, along with hydrometric and meteorological variables, were analyzed during the training and validation periods, and the best combination of predictor variables was determined based on the RMSE, MAPE, R², and Nash indices. To simulate the impacts of climate change, three climate models, including BCC-CSM2, MRI-ESM2, and CNRM-CM6-1, were selected, and downscaling was performed using the LARS-WG model under three greenhouse gas emission scenarios: SSP1-2.6, SSP2-4.5, and SSP5-8.5. The results indicated that the average temperature is expected to increase, while precipitation is projected to decrease. Consequently, the inflow to the Karaj Dam during the 2021–2050 period is expected to decrease by approximately 16% compared to the baseline period. This reduction in inflow is accompanied by increased uncertainty in future periods and may have significant impacts on regional water resource supply.