The Study on Fundamental Properties of

Based on the observed data which were collected from 177 gauging stations, the stochastic properties of sequential variations of natural runoff of main rivers in China has been probed with the theory of stochastic process and technology of time series analysis. The theory and technology can demonstrate many kinds of characteristics of the annul runoff time series; the trend, periodicity, serial correlation, and pure random. The trends of these annual runoff sequences may generally not be significant for large river and the almost periodicities of the sequences are mainly influenced by astronomic and climatic factors. The study also shows that the sequences exist the time dependence and the persistence in many rivers, and the cross-correlation coefficients between two annual runoff sequences vary in a wide range from positive to negative for the four largest rivers in China, but the simultaneous relation of annual runoff between the two largest rivers in China, Yangtse River and Yellow River, appears to be positive. These results are important for feature research of the water resources and environment assessment. [The Journal of American Science. 2005;1(1):46-54].