Analysis of runoff characteristics of Tuwei River and impact of human activity

The uneven distribution,concentration degree and variation amplitude of the Tuwei River runoff are calculated in detail based on the monthly runoff data measured at Gaojiachuan hydrological station from 1956 to 2005.We use the method of moving average and Mann-Kendall rank correlation to analyze the annual runoff change trend and the affections of precipitation and human activities on runoff quantitatively.The results show that intra-annual distribution of runoff is relatively even since 1970s,and the largest runoff appears in August;the annual runoff has obviously declined since 1980s,and human activity is the main cause of the obvious decrease and its impact has been increasing.