Environmental Risk Analysis Of Water Conservancy And Application To Wangjiashan Reservoir

Risks in water conservancy caused by many uncertain factors are cared about by people. Fuzzy theory and risk theory are used in the environmental risk analysis of water conservancy, and applied to the project "Research on risk analysis of Wangjiashan reservoir". A mathematical model of optimum impounded level considering environmental risk is established based on it. The subject of the thesis originated form practical project, and its research results supplies some valuable reference suggests to feasibility study and operation and supervision for the reservoir. The main contents are outlined as follows:Firstly, the definition and characters of risk, the theory and method of risk analysis, uncertainty analysis and the computation methods for unit failure probability are introduced. The conception, content and procedures of risk analysis are explained, and the classification and analysis method of uncertainty are researched. Uncertainty factors in water conservancy are described.Secondly, the characters of fuzzy mathematics are analyzed and the methods for determining membership function are outlined. Fuzzy comprehensive evaluation is introduced, and then fuzzy theory, organically combined with risk theory, is applied to project risk analysis.Thirdly, it is determined that environmental risk factors of water conservancy(considering Wangjiashan reservoir) comprises construction period risk, dam-break risk and submergence risk, and these three risks are decompounded, then hierarchy figure of risk factors is constructed. The environmental risk model is established, and a benefit-risk model considering environmental risk is established based on the former model.Finally, utilizing fuzzy comprehensive evaluation, the environmental risk model is solved combining with Wangjiashan reservoir project. Fuzzy scores are used to measure risk, and the total risk degree of the environmental system and the risk degrees of risk factors under the different impounded levels are calculated; optimum impounded level model of Wangjiashan project is established and computed, and its optimum impounded level is determined; the establishment, calculation and optimization result of the model are reasonable.