Fuzzy Partition Of Flood Season And Determination Of Limited Water Level On Zhangze Reservoir

The limited water level of controlling flood is an important and sensitive index in reservoir flood-control dispatching, the reasonable limited water level can solve efficiently the conflict between reservoir's flood control and it's benefit, and the aim of reducing flood disaster loss and getting maximum system profit can be realized. Through many years run, zhangze reservoir's conflict is sharpen. So according to the actual demand of project, it is very urgent to describe scientifically zhangze reservoir's flood season, to define reasonably it's limited water level and to find a dynamic control method for it's limited water level.In this paper, the conception and the theory of fuzzy set wasfirst stated, the theory that flood season has uncertainty and belongs to fuzzy sets was also presented. Then according to the present meteorology and project condition of zhangze reservoir, flood season staging was discussed using the methods of genetic analysis, mathematical statistics analysis and the fuzzy set analysis. The new idea about the selection of flood season staging index was used in this paper, that is to say the occurring time of the first and the last flood in one year was used as the staging index of flood season. Then relative membership grade of every time point in flood season was calculated in application, and the curve fitting was made for the parameter of the membership function. So that the fitting membership grade was got, it as the final membership grade of flood season, at last the fuzzy limited water level of zhangze reservoir was determined.In order to use water resources efficiently, the limited water level of zhangze reservoir was heightened based on the storage routing result, and then the limit risk analysis was made for the limited water level of fuzzy set, this made the graph controlmethod of the limited water level more perfect.In this paper, the limited water level of controlling flood was determined by using the analysis method of fuzzy set, and it was compared with the actual operation scheme. Then the conclusion was got that the result could increase the utilization quantity of water resources and solve reasonably the conflict between reservoir's flood-control and it's benefit.