The Research of Runoff Variation Characteristics of Wei River Basin

The research of basin runoff is one of the most important areas of research in surface water hydrology. This paper made an analysis of the runoff change trend and mutation characteristics of Wei River basin by the mathematical statistics of Kendall rank correlation coefficient and M-K mutation test method with the annual and monthly runoff data of Hua Country hydrological station from 1960 to 2005. The result showed the runoff of Wei River basin had a trend of decline all four seasons and the change trend would remain in the future. The annual runoff m utation of Wei river basin occurred in 1981, the runoff mutation of spring occurred in 1966 and at the earliest time, the runoff mutations of summer and autumn respectively occurred in 1977 and 1985, close to the annual runoff mutation time, the runoff mutation time of winter was uncertain. The precipitation didn't change too much before and after mutations, the mutations may be caused by human activities.