Study on the synchronous-asynchronous encounter probability of annual runoff series in Luanhe river basin

The synchronous-asynchronous encounter probability of annual runoff series in Luanhe river basin is studied, and it provides scientific basis for the rational allocation of water resource in the region. Copula function and bivariate joint distribution are constructed and used in the natural inflow time series of Panjiakou Reservoir, Taolinkou Reservoir and Yuqiao Reservoir, and then the synchronous-asynchronous encounter probability of rich-poor inflow of three reservoirs is analyzed. It is shown that both rich and poor synchronous frequencies of three reservoirs are very high, and the encounter probability of rich-poor inflow which is unfavorable to transferring from Panjiakou Reservoir is up to 35% 40%. To ensure the water supply safety of the Tannin, Qinhuangdao and other cities in Bohai region, the optimal operation of reservoir group must be enhanced to give full play to regulation and storage function. On one hand, the disadvantageous of the unfavorable encounter probability of rich-poor can be reduced; on the other hand, it is very important to accelerate the construction of South-to-North Water Transfer Project and promote the transformation to water-saving society.