ANALYSIS ON THE STATISTIC CHARACTERISTICS OF RUNOFF TIME SERIES IN THE YELLOW RIVER MOUTH AREA

摘要

Stochastic model of time series is used to study runoff at the Lijin Hydrological Station in the Yellow River estuary during 1950-2000. The results show that there exists a decreasing trend of the runoff series. The series may be divided into three phases with 1968 and 1985 as demarcation. The annual runoff decreased gradually and came to 14.38 billion m3 during 1986-2000. The phenomenon is related to not only climate factor but also human activities. The excess water diversion in the lower reach is the main cause of zero flow in the mouth area and shore erosion. Therefore the lowest runoff for maintaining ecological environment guaranteed.