Detecting changes in extreme streamflow in the Tarim River, Northwest China

We analyzed the characteristics of streamflow changes in the Tarim River Basin using daily data collected at 7 hydrological stations. We ran the nonparametric Mann-Kendall test to detect trends in hydrological extremes. We also applied the Indicators of Hydrological Alteration (IHA), to assess flow regime variations. The results indicate that: (1) the hydrological extremes in headwater experienced increases in magnitude, duration, and high flow frequency; the mainstream exhibited increases in low flow duration and low flow frequency, and a decrease in high percentile flow and high flow frequency; (2) The trends of extremes related to minimum flow is greater than maximum flow; the date of maximum flow in both the headwater and mainstream has advanced; the most drastic changes in extreme streamflow occurred during winter; (3) Climate change has considerably altered flow regime in the headwater. Although climate change has profoundly affected the water supply upstream, human activities are dominant in determining flow regime.