Abstract: Climate change and human interferences have induced alterations in the streamflow of many rivers. An important issue is to understand the causes of historical streamflow changes and meanwhile explore their evolving trends in the future. This paper presents an application of the SWAT model to the Taoer River basin. We quantify the impacts of climate change and human activities on the streamflow changes in historical period, and apply the model to project the trends in the streamflow changes under different future climate scenarios. Results indicate that in the historical period, the annual mean air temperature was increasing significantly, whereas precipitation and streamflow decreased. Climate change and human activities were the main causes of streamflow changes in the upper and lower reaches, respectively. Under the BCC-CSM2-MR (CMIP6) climate scenarios in the future, annual streamflow is projected to decrease, indicating a more challenging situation in water resources utilization. This study reveals the causes of historical streamflow alterations and the future trends of water resources, helping water resources planning and management in the basin scale.

Key words: climate change, human activities, streamflow, attribution analysis, Taoer River