Study On Flood Season Staging And Adjustment Of Flood Limited Level On Qiyi Reservoir In Jiangxi Province

China is one of the countries with severe water shortage in the world.With the population growth and the development of the national economy,the contradiction between supply and demand of water resources has become increasingly prominent.Therefore,relying on the improvement of contemporary scientific and technological level,the full potential of reservoir regulation and storage can be fully utilized,and part of the flood can be converted into usable water resources in a timely manner under the premise of control of flood control risks,thereby improving water resource utilization.It is of great significance to alleviate the water resources crisis and improve the ecological environment.The flood limited water level is an important factor affecting flood control operation of reservoir.There are many theories and methods for determining the flood limit water level,and choosing the appropriate flood limit water level adjustment scheme when the reservoir is storing water according to the different conditions of the project is an effective way to solve the contradiction between the reservoir flood control and profitability.Therefore,it is very necessary to study the stages of the flood season of the reservoir and the adjustment of the flood limited level.In the flood periods of many reservoirs,for the safety of flood control,the water level of the reservoir must be controlled at a low level,cause a large amount of flood water is wasted,and the flood water resources are not comprehensively utilized.To coordinating the contradictions between flood control and profit promotion to reservoirs,further exploiting and utilizing the water resources in flood periods,This thesis selects Qiyi Reservoir as a typical reservoir in Jiangxi Province,discusses the optimal management plan of the reservoir comprehensively from the three stages of flood season,determination of flood limit water level and risk benefit analysis,and draws scientific and feasible conclusions.Taking the Qiyi Reservoir Project in Jiangxi Province as an example,the fuzzy set analysis method and the system clustering method were used to stage the flood seasons of the reservoir,and combined with the current staging scheme of the reservoir,the following staging results were obtained:The first flood season is from March 1 to April 30,the main flood season is from May 1 to June 30,and the latter flood season is from July 1 to August 31.Based on the stage of flood season,the experience and theoretical membership degree obtained by fuzzy analysis is used to calculate the flood control reservoir capacity,so as to derive the fuzzy flood limit water level process line of the reservoir.Based on the risk-benefit analysis theory,with the water resource utilization rate as the benefit index and the reservoir flood control risk rate as the risk index,according to the establishment of the optimal model of the dynamic control scheme of the flood limit water level under each risk control index,the risk benefit under the adjustment of the reservoir flood limit water level is analyzed.