A Synchronous-asynchronous encounter risk management model of rich-poor runoff and pr-ecipitation in the upper,middle and lower reaches of Dongjiang river basin was developed using a combined approach based on the copula function and Bayes-net works and the interrelation of runoff and precipitation among different three stations were intuitively described.Based on the Copula function,the joint distribution model was established to calculate the risk probability of the diversion adverse situation of Synchron...