Runoff Variation Trend of Three Diversions in Recent 60 Years and the Analysis of Influencing Factors

摘要

Three-diversions is the only channel of the runoff between the Yangtze River and Donting Lake. So it is meaningful to study the variation of runoff and the causes of such change in three diversions. By accumulative anomaly analysis method, the changing of runoff and the inflection points are analyzed. The results show the runoff decreases in the recent 60years and the inflection point was in the late 1960s and early 1970s. And then the comparative method of the slope changing ratio of accumulative quantity is used to compute the contribution rates of each factor to the runoff variation. The results show the precipitation is significant to the runoff variation, and the contribution rates of hydraulic engineering increased first, then decreased and tends to be stable.