Long-term response of runoff and sediment load to spatiotemporally varied rainfall in the Lhasa River basin, Tibetan Plateau

•Runoff and sediment load responses to rainfall-related parameters were quantified in a typical alpine basin.•The combined effects of multiple driving factors on runoff and sediment load were discussed by using PLS-SEM.•Rainfall dominated the variation in runoff and sediment load, but its action gradually weakened after 2005.•Vegetation did not limit runoff but did reduce the sediment load with the increase in vegetation coverage.•Climate, vegetation cover, and snow jointly explained 73.9–76.7% and 39.2–52.4% of the total variability in runoff and sediment load, respectively.