Research On Issues Related To Efficient Utilization Of Flood Control Capacity Of Multi-reservoir

The flood disaster is one of the most common natural disasters,which has become a major obstacle to sustainable development of society and economy.The combination of flood control engineering measures and non-engineering measures is an effective way of basin flood control.Under the new situation that "coordinated efforts to champion environmental protection and eschew large-scale development",the multi-reservoir joint flood control scheduling method,which improves the overall flood control capacity of multi-reservoir,is a core technology issue that need to be addressed urgently in the basins flood control work.Focused on the key issues of efficient utilization of flood control capacity,the variable-parameter nonlinear Muskingum model and its parameter optimization were studied in this thesis.Afterwards,this thesis proposed the flood control capacity optimization allocation strategy to improve the overall flood control efficiency of the basin,and built the flood control capacity optimization allocation model,which was used to analyze the correlation and effectiveness of reservoir flood control capacity utilization to realize efficient utilization of flood control capacity of multi-reservoir.The research achievements of this thesis had important scientific and theoretical significance and practical application value.The main works and innovative achievements of this thesis were summarized as follows:(1)Directed at the problem of low precision of the traditional linear Muskingum model,the nonlinear propagation law of reservoir discharge in the downstream channel was analyzed,and two variable-parameter nonlinear Muskingum models(DVEP-4PNL-L and DVP-3PNL)were presented in this thesis.These two models considered these parameters varied with the inflow,which made these could accurately simulate the nonlinear movement of flood in the river,and improved the precision of river flood routing.(2)In order to solve the parameter optimization problem of variable-parameter nonlinear Muskingum models,a new hybrid optimization algorithm(AGANMS),which combined the adaptive genetic algorithm(AGA)and the Nelder-Mead simplex(NMS)algorithm,was proposed based on the idea of complementary advantages combination.And then the AGANMS was tested by using six different types of test functions.Meanwhile,the AGANMS was used for parameter optimization of the DVEP-4PNL-L and the DVP-3PNL,and verified the excellent performance of both models.(3)Focused on efficient use of flood control capacity in the joint flood control operation of multi-reservoir,this thesis studied the method that explored the rational use of flood control capacity of reservoir and reduced the overall flood control risk of the basin,and then two optimization allocation strategies for flood control capacity of reservoirs were proposed.The first optimization allocation strategy was the strategy of maximizing the variable weight reserved flood control capacity,and the weight calculated by this strategy changed with the scheduling period,which solved the problem that the weight varied from person to person.The another optimization allocation strategy was the strategy of maximizing system nonlinear safety degree,the reservoir safety degree calculated by this strategy was gradually reduced with the use of reservoir flood control capacity,and the declining rate gradually increased.The flood control scheduling results of five reservoirs(Xiluodu,Xiangjiaba,Zipingpu,Pubugou and Tingzikou)located in the Chuanyu section of the Yangtze River showed that the latter made the distribution of flood storage capacity of each reservoir more scientific and reasonable,so as to reduce the flood control risk of reservoirs system and improve the overall flood control effect of multi-reservoir.(4)To research the correlation and effectiveness of reservoir flood control capacity utilization in the joint flood control operation of multi-reservoir,the reservoir flood control capacity equivalent ratio was defined,and a quantitative method for studying the equivalence of reservoir flood control capacity was proposed.Afterwards,the equivalences of flood control capacity between the tributaries reservoirs and the mainstream reservoirs in the study area were studied,which provided theoretical support to effective utilization of flood control capacity of reservoirs and improved the comprehensive flood control efficiency of reservoirs.