Study On Joint Operation Of Water And Sediment In Sediment-laden Reservoir In Liao River Basin

Reservoirs built on the sediment-laden river will suffer from mud filling inevitably, the impacts of reservoir sedimentation on reduction of reservoir storage capacity, conveyance capacity of downstream river and ecological environment cannot be ignored. Liao river is a sediment-laden river, the basin’s water resource is not rich and distributed unevenly in temporal and spatial, especially due to the social and economic development of middle and downstream region rapidly, which aggravates the contradiction between flood control, sediment ejection and water supply of reservoirs. Therefore, the research of new dispatching method of reservoirs and its related technique, which can not only enhance utilization efficiency of water resource, but also ensure the flood control safety and service life of upstream and downstream of reservoir, is needed urgently to satisfy the new requirement of people’s life level, social and economic development to water resource. The rainfall in the year of Liao river basin is mainly in flood season, and incoming water and sediment of reservoir are mainly come from one or two flood in flood season, so the contradiction between flood control, sediment ejection and storage of reservoir is more acute if we can not utilize the limited flood resources to storage and sediment of reservoir adequately. To solve this problem, based on Shifosi reservoir on the main stream of Liao river and Naodehai reservoir on Liu river branch, this paper studied the prediction and joint control of incoming water and sediment to improve the use of flood resources. The main content and achievement as follows:(1) The study on the prediction of sediment in sediment-laden reservoir in Liao river. Firstly, the inflowing water and sediment features of Shifosi reservoir and Naodehai reservoir were analyzed. Secondly, the characteristics of water and sediment about Shifosi reservoir were studied by using correlation analysis method, and a multiple regression equation for prediction of coming sediment in Shifosi reservoir was established. so simulation of incoming sediment was applied in order to provide basis for studying the dispatching of sediment ejection and storage of reservoir. Finally, the major factors of coming sediment were confirmed by analyzing the characteristics of water and sediment of Naodehai reservoir, the sedimentation prediction model based on BP neural networks was established, the result predicted by this model is better, and it was useful for guiding actual dispatching of reservoir.(2) The study on principles of sediment ejection in Shifosi reservoir area. Firstly, the sediment influence factors of reservoir area are analyzed qualitatively by using trend analysis method, in order to determinate the major factors of sediment deposition; Secondly, according to water and sediment data in Shifosi reservoir for decades, the gray correlation degree analysis was applied to study the contribution ratio of every factor on the reservoir sedimentation; Finally, the sedimentation prediction model of Shifosi reservoir based on BP neural networks was established based on the above analysis, it can provide the sediment ejection in reservoir area and references to establish schemes of the joint control of incoming water and sediment.(3) The study on dispatching rules of Shifosi reservoir considering sediment deposition. Since impounding water formally, the running status of sediment deposition in Shifosi reservoir were presented. The dispatching method and reservoir sedimentation during2010to2012were analyzed, combining with the requirement of flood control, sediment ejection, water supply and ecological regulation. The dispatching scheme, which is based on analysis of sediment ejection and deposition in reservoir area, was established by considering rules of sediment deposition in reservoir, that can consider the need of ecological, sediment ejection and water supply at the premise of flood control safety. This new dispatching scheme obtained satisfactory comprehensive utilization effect in real-time scheduling in the year of2013. Therefore, this new dispatching scheme could be applied in guiding the real-time scheduling of Shifosi reservoir.Conclusions of research achievements are summarized accordingly in the end of this paper, and problems need to be studied further are proposed.