Abstract: To study the hydrological responses of a river basin to environment changes such as climate and land use changes is of great value to water resources utilization. This paper presents a quantitative analysis on the contribution rates of climate change and human activities to runoff change, using seven elasticity methods based on the Budyko framework and a SWAT model. In a case study of the upper Han River upstream of the Shiquan hydrological station, various scenarios of climate change and land use change are examined. The results show that annual runoff at this station underwent a decreasing trend. Climate change accounted for 65.3% - 68.1% of the runoff decrease and human activities for 31.9% - 34.7%, indicating that climate change was the major factor causing the runoff decrease in recent 56 years. Simulations of the climate change scenarios show that precipitation is the dominant factor in the runoff change, and that the annual runoff increases in the scenarios of natural land use growth and extreme grassland but decreases in the scenarios of farmland return to forest, extreme cultivated land, and extreme woodland.

Key words: climate change, human activities, SWAT model, elasticity method, Han River