| The Heihe River is a typical inland river,located in arid and semi-arid areas of Northwest China,so the water resources in there are particularly precious.With the continuous development and utilization of water resources in the Heihe River,eight cascade reservoirs have been planned and constructed in the upper reaches,of which Huangzangsi,as the leading reservoir,is an important water control hub;the middle reaches is the main grain-producing area,where the demand for irrigation water is large,and the squeezing of water in the lower reaches occurs from time to time,threatening the health of the ecosystem of downstream.Therefore,in order to alleviate the contradiction of water use in the middle and lower reaches and improve the ecological environment in the lower reaches,it is necessary to carry out the reservoir ecological dispatch and provide technical support for the operation and management of the reservoir.In this paper,Huangzangsi Reservoir is taken as the research object,the ecological dispatching target of Huangzangsi Reservoir is established based on the current ecological situation of Heihe constructeded,and the quick non-dominant genetic algorithm(NSGA-II)with elite strategy is used to solve various scenarios,and the best scheme in a typical year is selected through the fuzzy optimization evaluation model.The research mainly draws the following conclusions:(1)Through the analysis of the ecological status and needs of the Heihe River Basin,the objectives of the ecological management of the Huangzangsi Reservoir are determined.The ecological base flow was determined by using the classical 90% frequency average runoff method in hydrology,the minimum monthly average runoff method in recent 10 years,the minimum monthly runoff method in typical years and the minimum monthly average measured runoff method.(2)Based on the Huangzangsi reservoir dispatching task and downstream ecological demand,a multi-objective reservoir ecological dispatching model with minimum cascade power generation,minimum irrigation water shortage,and minimum ecological water deficit rate is established,and a fast non-dominated genetic algorithm(NSGA-II)with elitestrategy is applied to the solution of the reservoir scheduling model(3)According to the water conflict in the middle and downstream reaches and the actual situation of supply and demand water in the Heihe River,13 scheduling scenarios were designed.Through solving the model,the spatial distribution characteristics of non-inferior solution sets and the features projected onto the two-dimensional plane are obtained.The results show that under all scheduling scenarios,when the cascade power generation is fixed,the sum of square of ecological water shortage rate decreases with the increase of irrigation water shortage;when the irrigation water shortage is constant,the sum of square of ecological water shortage rate increases obviously with the increase of cascade power generation.By comparing and analyzing the typical dispatching scenarios in the typical year,it is found that the contradiction between ecological water use and irrigation water use is aggravated,and the increase of irrigated area in the middle reaches affects the downstream ecological water supply,and finally selected the scenario 1,the scenario 5 and the scenario 10 as scenarios for providing ecological scheduling decisions.(4)Through the construction of evaluation index system,on the basis of comprehensive determination of index weight by the subjective and objective methods,the fuzzy optimization evaluation model is established,and the optimal schemes for three typical years are obtained.The recommended scheduling process is given,which provides decision support for the operation management and scheduling scheme of Huangzangsi Reservoir... |
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