Changes in intra-annual runoff and its response to climate change and human activities in the headstream areas of the Tarim River Basin, China

Intra-annual runoff trends and periods in the headstream areas of the Tarim River Basin were investigated by non-parametric tests and wavelet analysis. The analysis was based on runoff data collected from six hydrological stations in the mountain headstreams and at the Alar station in the main stream of Tarim River Basin combined with the regional meteorological data collected from 1957 to 2008. The impacts of human activities and climate change on the runoff quantities during high-flow periods were investigated by structuring models. The results showed that (1) the runoff, air temperature and precipitation of the headstreams increased remarkably during both high-flow and low-flow periods. (2) In mountain headstreams, the concentration degree index (CDI) at the Xiehela hydrological station increased slightly, while the indexes at the other five stations (Shanliguilank, Kaqun, Yuzmenlek, Tongguzlek and Wuluwati) showed decreasing trends. (3) The CDIs of runoff in the mountain headstreams had significant periods of 3–8 years, which were similar to those of air temperature during high- and low-flow periods, but differed from those of precipitation. (4) Both climate change and human activities had significant effects on the total runoff of oasis headstreams during the period of 1993–2007, and climate change was a leading factor driving runoff evolution of oasis headstreams during high-flow periods. Overall, the results of this study provide a scientific basis for realizing reasonable allocation of water resources in the Tarim River Basin.