| Yanshan Reservoir located on the upper trunk of Lihe River,the main tributary of Shaying,River in the Huaihe River Basin,is a large(II)reservoir mainly for flood control,integrated with water supply,irrigation and comprehensive utilization of power generation.In recent years,with the impact of climate change and human activities,the natural inflow runoff of Yanshan Reservoir has decreased,as well as the change of regional water consumption and the lack of a reasonable profit dispatching scheme,the contradiction of regional water consumption has become obvious.Therefore,it is of great significance to carry out multi-objective optimization dispatching and Scheme Optimization Research of Yanshan Reservoir under the influence of climate change and human activities for guiding reservoir dispatching and operation,improving regional water resource utilization efficiency and alleviating water conflicts.This paper takes Yanshan Reservoir as the research object,systematically analyses the evolution law and development trend of natural inflow runoff,constructs multi-objective optimization dispatching model of Yanshan Reservoir and comprehensively optimizes reservoir dispatching scheme,aiming at providing reference basis for optimal operation of Yanshan Reservoir.The main research contents and achievements of this paper are summarized as follows:(1)Based on the data of natural inflow runoff of Yanshan Reservoir from 1955 to 2020,using Cox-stuart and Mann-Kendall nonparametric test methods,the annual and interannual runoff variation laws of Yanshan Reservoir are systematically analyzed,the abrupt change of inflow runoff is diagnosed,and the periodic change trend of natural inflow runoff of Yanshan Reservoir is analyzed by continuous wavelet transform according to the characteristics of natural inflow runoff of Yanshan Reservoir in multi-time scale.The results show that the natural inflow runoff of Yanshan Reservoir is unevenly distributed in a year and the distribution process is of single peak type.The natural inflow runoff of Yanshan Reservoir has a downward trend as a whole,and most of the interannual runoff sudden changes occurred in1963 and 1993.The main period of natural inflow runoff change of Yanshan Reservoir is 55 years,and the four-season runoff corresponds to the main period of 14,34,29 and 11 years respectively.(2)Considering the basic water supply target and ecological flow threshold of Yanshan Reservoir comprehensively,the multi-objective optimization dispatching model of Yanshan Reservoir is established and optimized by using MATLAB.According to the original designed ecological flow rate of the reservoir,combined with monthly frequency analysis method and recommended index of international river ecological water demand,the threshold range of ecological flow is determined according to this research institute.Three typical years,namely rich,flat and dry,are selected,and the profit target of 2025 is taken as input parameter of the model.The water level at the end of dispatching period is taken as state variable,and the water level at the end of reservoir period is discretized according to 0.1m.The model is programmed and solved according to the algorithm diagram drawn.The results show that the water resource utilization rates of the three years are 33.84%,53.83%,77.30%,respectively.The water resource utilization rate is significantly improved compared with the current situation.(3)An index system for optimum selection of Yanshan Reservoir Dispatching Scheme is established,which covers indexes of water resources development and utilization,water economy,ecological health,water source stability,etc.The indexes of the optimum index system are combined and weighted by AHP,Entropy Weight Method and Minimum Relative Entropy Principle.Based on the analysis results of comprehensive benefits of each scheme,the subordination vector of the scheme set is obtained by using the fuzzy mathematical method and the fuzzy relationship matrix.Comprehensive evaluation of dispatching schemes under different scenarios.The result shows that the optimum dispatching scheme has a goodwill of 0.83382 and corresponds to the total water supply of 14125.34 Cubic metre during the dispatching period,Total water discarded during dispatching period is 7329.88 million Cubic metre,Upper bound water volume over ecological flow interval is 312.06 million Cubic metre,533.29 million k W·h is generated by discarded water and water supply flow,and the utilization rate of water resources is 45.72%. |
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