Research On Combined Flood Control Operation And Storage Capacity Allocation Of Controlled Reservoirs In The Upper Reaches Of The Yangtze River

Flood disaster is one of the major natural disasters that occur frequently and cause huge losses in China.In order to achieve the goal of flood control and disaster reduction,China has planned and built a large number of water conservancy engineering facilities,in which the Yangtze River Basin has built a huge reservoir group system with the Three Gorges Reservoir as the core and dozens of reservoirs cooperating.If non-engineering measures such as scientific and effective overall dispatching are implemented on the basis of flood control engineering measures,the flood control potential of giant reservoirs can be further tapped and the flood control pressure in the Yangtze River Basin can be effectively reduced.However,due to the different ownership,completion time,flood control needs and flood control tasks of reservoirs in the basin,a unified joint flood control dispatching and management mechanism has not yet been formed,which makes it difficult to make full use of the huge flood control compensation capacity of reservoirs and obtain greater flood control benefits.Therefore,this paper focuses on the integrated mechanism of the joint flood control operation of the controlling reservoirs in the upper reaches of the Yangtze River and the key scientific and technical problems in the rational allocation and operation of the reservoir capacity.By using optimization theory,dispatching method and system science theory,the joint flood control operation and reservoir capacity allocation of the controlling reservoirs in the upper reaches of the Yangtze River are studied.The main research contents and innovative achievements of this paper include:(1)In order to coordinate the contradiction between the local flood control demand of Chuanjiang reach and the overall flood control demand of Yangtze River basin,based on the analysis of the flood control situation and flood encounter in the basin,the mixed reservoir group composed of Xiluodu,Xiangjiaba and Pubugou reservoirs is selected as the research object,and the optimal operation model of joint flood control with the goal of maximizing the remaining flood control reservoir capacity is constructed.SOS2 special sequence set and 0-1 integration are adopted.The mathematical programming method is used to linearize the model.By simulating the joint flood control dispatching process under different initial water levels,the passive flood control problem of reservoirs is analyzed,and the minimum consumption reservoir capacity required to ensure the flood control safety of the Chuanjiang reach is solved,and the maximum remaining flood control reservoir capacity of the joint flood control dispatching reservoir group is deduced.(2)Focusing on the problem of reservoir capacity allocation and utilization under the condition of ensuring the safety of flood control control stations,the concept of reservoir capacity benefit of unit reservoir capacity for reducing peak flow of downstream flood control control stations is innovatively defined,and a reservoir capacity allocation method aiming at maximizing the benefit of flood control reservoir capacity is proposed.Taking Yibin Flood Control Station(Lizhuang)as an example,a joint flood control dispatching model for upstream reservoirs is established to ensure the safety of flood control control points and maximize the flood control benefits of upstream reservoirs,which verifies the rationality and effectiveness of the proposed method.(3)In order to give full play to the benefits of joint flood control dispatching of reservoirs,an optimal joint flood control dispatching model aiming at the highest flood level and the lowest flood level of the Three Gorges is established for the three Gorges single reservoir flood control dispatching,the river-to-cascade flood control dispatching,the stream-to-cascade flood control dispatching,the stream-to-direction cascade,the waterfall ditch,the Tingzikou,the Goupitan and the Three Gorges reservoir.The effects of different typical inflow conditions on the inflow of the Three Gorges reservoir,the maximum flood level of the Three Gorges and the flood diversion in the middle and lower reaches of the Yangtze River are analyzed.The results show that joint flood control dispatching can give full play to the flood control potential of upstream reservoirs and reduce the flood control pressure in the middle and lower reaches of the Yangtze River.In order to ensure that each reservoir completes its flood control task and conducts joint flood control dispatching,different reserved reservoir capacity schemes are further proposed,and the effects of different reserved reservoir capacity schemes are compared and analyzed.The results show that the reserved reservoir capacity schemes play an active role in joint flood control dispatching.(4)Combining with the actual application demand of the project,aiming at the highest flood level and lowest flood level of the Three Gorges Project,considering the flood control tasks and dispatching needs of each reservoir,a simulation-optimization flood control dispatching model of the controlling reservoir group in the upper reaches of the Yangtze River is established,and the dispatching rule set of the reservoir group is extracted.This paper compares and analyses the dispatching results of different dispatching rules schemes under different typical water inflow situations,and recommends reasonable and available flood control dispatching rules schemes.The results show that the scheduling process and results of the proposed joint flood control dispatching rule scheme are reasonable and effective,which can provide a reference for the application of the joint flood control dispatching project of reservoirs in the upper reaches of the Yangtze River.