Streamflow Consumption vs. Climate Change in the Evolution of Discharge in the Tarim River Basin, Northwest China

Quantifying and separating the impacts of hydroclimatic change and human activities on streamflow consumption are crucial issues for the planning, management, and rational allocation of water resources in arid inland river basins. Generalized additive models were used to reveal the interactions between climate, land-use change, and streamflow consumption in the mainstream Tarim River basin in Northwest China. The results showed that streamflow has decreased, while streamflow consumption has had an increasing trend in the upper reaches and a decreasing trend in the middle and lower reaches during the past 45 years. Land-use change was estimated to contribute 50.1–84.30% (mean of 58.1%) of streamflow consumption, and it was followed by climatic change, which contributed 10.5–28.3% (mean of 21.5%), and inflow runoff, which contributed 11.8–23.6% (mean of 17.7%) from 1970–2015. Land-use change played a dominant role in streamflow consumption in the mainstream Tarim River basin. Cropland expansion and urban area growth were the primary factors causing the decreased streamflow and increased streamflow consumption in the upper reaches. The streamflow consumption in the middle and lower reaches decreased, which was attributed to the decreased inflow. The results are useful for informing policy-making accordingly so that the river can be properly restored, which will benefit the ecosystem services