[Impacts of human activity on Bayin River runoff as revealed by tree rings in Qaidam Basin, China].

Evaluating the impacts of human activity on river runoff has important implications for regional water resource management. Here, we used seven tree-ring width chronologies to establish a regional mean tree-ring width chronology from the northern mountain of Delingha, Qaidam Basin. We conducted the correlation, moving correlation and regression analysis of regional mean tree-ring width chronology with runoff data from Bayin River gauge station. Then, we stimulated the June runoff of Bayin River from 1956 to 2002. The results showed that the highest correlation coefficient was found for June runoff (=0.63, <0.01), and their moving correlation coefficient decreased after 1986. Based on the stable relationship between tree-ring width chronology and the June runoff during 1956-1986, we built the reconstruction function, which was explained 50.8% of observed runoff. The stimulated runoff during 1987 to 2002 was significantly higher than the observed runoff (3.01 m·s, <0.001). These results indicated that human activity from the upper river had significant impacts on Bayin River runoff. Human activity should be considered as an important factor to protect security of sustainable water resource utilization for future water resource development and utilization in Bayin River region.