Climate change is one of the major challenges affecting natural ecosystems and various aspects of human life. The effects of global warming on the hydrology and water cycle in nature are very serious, and the quantitative recognition of these effects creates more readiness to deal with its consequences. In the present study, the 2006–2100 period is predicted based on the statistical downscaling model (SDSM). Finally, the effects of climate change on the hydrological conditions in the Darabad watershed are simulated using the Soil and Water Assessment Tool (SWAT) model. The SWAT model calibration is done based on the SUFI-2 algorithm, and the effective and optimal parameter is identified. The results of the study, while confirming the efficiency of both SDSM in climate simulations and SWAT in hydrological simulation, showed that the increase in precipitation and temperature is probably in future climate conditions for the 2010–2040 period. The surface flow and runoff at the watershed area during the observation period (1970–2010) is 0.29 m³/s, but this value for the predicted period with regard to climate change in the RCP 2.6, RCP 4.5, and RCP 8.5 scenarios is equal to 0.43, 0.44, and 0.45 m³/s. The results of research, while highlighting the importance of effects of climate change, make it essential to apply them for proper management in order to adapt to climate change in the future policies of the Darabad watershed management.

气候变化是影响自然生态系统和人类生活各个方面的主要挑战之一。全球变暖对自然界的水文和水循环的影响非常严重，对这些影响的定量认识使人们更加愿意应对其后果。在本研究中，基于统计缩减模型（SDSM）预测了2006-2100年。最后，使用土壤和水评估工具（SWAT）模型模拟​​了气候变化对达拉巴德流域水文条件的影响。基于SUFI-2算法完成SWAT模型校准，并确定有效和最佳参数。研究结果，同时确认了SDSM在气候模拟中和SWAT在水文模拟中的效率，研究表明，降水量和温度的升高可能是在2010-2040年的未来气候条件下。在观测期间（1970-2010年），集水区的地表径流为0.29 m³ / s，但在RCP 2.6，RCP 4.5和RCP 8.5方案中，有关气候变化的预测期间的该值等于0.43、0.44和0.45 m ³ / s。研究结果在强调气候变化影响的重要性的同时，有必要将其应用到适当的管理中，以便在达拉巴德流域管理的未来政策中适应气候变化。