Abstract: Located in the south-central part of the Tibetan Plateau, the Lhasa River Basin is one of the most sensitive areas to climate change due to its unique geographical location, and is also a densely populated and cultivated area on the Tibetan Plateau. The impact of climate factors and land use on runoff is quantified and analyzed in this paper by simulating runoff in the Lhasa river basin using different climate scenarios and land use conditions based on a SWAT model. Climate change and land use exerted an influence on runoff by approximately 82.95% and 17.05%, respectively. The main reason is that land use in the Lhasa River Basin has changed little over the last three decades, while temperature and precipitation have increased significantly. For every 10% increment in precipitation, basin runoff grew by about 11.8%, and the sensitivity of runoff to precipitation is of low spatial variability. For every 1 ℃ increase in temperature, basin total runoff increased by about 2.5% with significant spatial variability in runoff changes: runoff in the middle and upper reaches fell by 0.7%, while runoff in the lower reaches rose by approximately 3.6%.

Key words: land use cover change, climate change, SWAT model, runoff, Lhasa River Basin