Research On Runoff Characteristic And Water-supply Risk Of Water Resources Source System Of Western Route Of South To North Water Transfer Project

First Phase Project of Western Route of South to North Water Transfer Project is a great water transfer project that transfers water resources from upper branches of the Yangtze River to upper reach of the Yellow River, and it bears great important practical significance to carry thorough and systematic research on runoff characteristic and supply risk of the water resources source system. Guided by systematic engineering methodology, this dissertation carried deep and aborative research on the runoff characteristic and supply risk problem on temporal and spatial dimensions from different points of view, and the research contents can be summarized as following:(1) Such methods as Kendall test method, R/S method, conditional probabilitymethod and Markov process method are proposed and applied to analyze thoroughly such change characteristics of the rivers as trend, durative, continuous rich and poor probabilities, one-step transition probabilities, limit probabilities and average recurrence time, etc.(2) Based on analyzing problems of wavelet transformation method, the annual runoff time series at the project area are decomposed into multiple time-scale series with EMD method and the physical backgrounds of each IMF fluctuation periods are discussed(3) Through analyzing complicated multiple time-scale and uncertainty characteristics of runoff time series fluctuation, to analyze deeply fluctuation relationships of annual runoff time series between rivers, EMD and SPA methods are combined to thoroughly display fluctuation uncertainty between the rivers at the project area on different time-scale.(4) Based on analyzing the shortages of current common models for two-dimension joint distribution, Copula method is presented and applied to construct two-dimension joint distribution model between rivers at the area and that between the rivers and the Yellow River, and then the encounter probabilities of rich-poor runoff between them are thoroughly analyzed and the probabilities that are favorable to make compensatory operation between the rivers at the project area and that favorable to transfer water resources to the Yellow River are presented.(5) Based on identification and analysis of influencing factors of water-supply risk analysis of the water transfer project, a risk assessment index system including such indexes as water-supply risk rate and reliability, recovery capacity, invalidation period is constructed, and water-supply risk analysis model of the project is presented, and then the risk is studied with Monte Carlo method based on monthly runoff series generated from stochastic simulation.In a word, the runoff change trends are unremarkable at the project area, the opportunities that the project can operate efficiently and implement compensatory operation are rather big and the water-supply efficiency and benefit of the water transfer project can be ensured.