Adjustment Of Staged Limited Level Of Reservoir During Flood Season And Risk Study

China is one of the countries in most sever water resources shortage. In the north of China, the situation is especially serious. With the increase of China population and the development of society and economy, the amount of water resources utilization and polluted water have been rising while the environment quality is deteriorating. This situation has become a main constraining factor of national social-economical continuable development. Therefore, flood water utilization is of great significance for relieving the crisis of water resources shortage and improving the environment quality which can be realized through fully excavation the potentiality of reservoirs storage based on scientific-technical advance while the flood control risk doesn't increase.A overall review of theoretic researches and scientific practices on adjustment & application of staged limited level of reservoir during flood season both domestically and abroad is drawn in this paper. Based on it, some key problems focusing on adjustment of staged limited level of reservoir during flood season, such as seasonal flood period partition, staged design flood computation and risk analysis & efficiency assessment of staged flood limited level adjusting are investigated.The Panjiakou reservoir basin is selected as the study object. Based on analysis of the atmosphere circuit influencing basin rainfall, the seasonal trend of rainstorm in Panjiakou reservoir basin is studied both by qualitative and quantitative methods. Rainstorm and flood seasonal change characteristics of Panjiakou basin are synthetically analyzed by statistical study on several points, namely rainstorm days of ten-day period, areal precipitation of ten-day period, different lasting time precipitation of ten-day period and reservoir inflow of ten-day period. In order to overcome the disadvantages of qualitative methods, six kinds of quantitative methods on flood season partition are introduced synchronously. Meanwhile, by contrastive analysis of their feasibility, the suitable method for flood season partition is recommended. Then, a scheme of flood season partition of Panjiakou reservoir is proposed.The consistency of flood series of Panjiakou basin is analyzed. And the historical flood and super flood in this basin are also confirmed. Based on these work and according to the flood season partition scheme, new achievements of design flood of Panjiakou reservoir are put forward by trans-periodical sampling. In the process of flood series sampling, the dependence of samples is fully considered.The flood control risk and efficiency analysis under the situation of reservoir flood limited level adjustment is another important point in this paper. Based on the uncertainty analysis of key factors, the influence on reservoirs flood control risk caused by flood limited level adjustment is evaluated from the two aspects of ultimate risk ratio and dam overflow risk analysis. Selecting a long series of day average inflow as input, a long series regulation simulation of Panjiakou reservoir is conducted. Then, corresponding possible efficiency under reservoir flood limited level adjustment is confirmed.Finally, based on a systematic analysis of main factors influencing flood limited level adjustment of Panjiakou reservoir, the reservoir staged limited level during flood season schemes are synthetically augmented from many aspects.