Cascade Reservoir Ecological Dispatching And Its Effect Response Analysis Considering Fish Reproduction Demand

Due to the construction and operation of water conservancy projects,the hydrological situation of the river will change accordingly,which will inevitably affect the ecological health of the river,and the change of fish resources is inevitable.In order to alleviate the reduction of fish resources and promote fish reproduction in the Xijiang River Basin,it is necessary to carry out research on the ecological regulation of cascade reservoirs to meet the needs of fish reproduction,and to explore the response changes of fish reproduction to the effect of ecological regulation.In view of the lack of comprehensive consideration of ecological runoff and hydrological process in the current ecological regulation of reservoirs,this paper takes the Longtan-Yantan cascade reservoirs,the main stream of the Xijiang River as the research object,based on the minimum ecological runoff method and monthly frequency calculation method.The minimum ecological runoff and suitable ecological runoff of the river channel are used as constraints;the IHA/RVA method and the Gaussian membership function method are used to identify and analyze the ecological and hydrological indicators that have a large degree of change after the construction and operation of the reservoir and have an impact on fish reproduction.The membership function and fuzzy weighting method construct the ecological integrity function,which is regarded as the ecological goal of cascade reservoir ecological regulation.Based on the adaptive artificial fish-swarm algorithm(AAFSA),the ecological scheduling model of cascade reservoirs considering fish reproduction needs was solved,and the calculation results and the improvement degree of each index were analyzed.Combined with the effects of changes in water quality factors during the fish breeding period in the downstream of Longtan-Yantan cascade reservoirs,the Pearson correlation analysis method and generalized additive model(GAM)were used to reveal the response changes of fish breeding to the effect of ecological regulation.The main research results are as follows:(1)Research on ecological regulation of cascade reservoirs considering fish breeding needs.In order to meet the ecological runoff and hydrological process required for fish reproduction,the basic ecological runoff required for fish reproduction at the Dahuang River Estuary Hydrological Station in the downstream of Yantan was calculated according to the ecological runoff research method,and the combination of IHA/RVA method and Gaussian membership function method was used.The eco-hydrological indexes with large degree of change and meeting the reproductive needs of fish are inferred,and then the Gaussian membership function method and fuzzy weighting method are used to calculate the membership value and the value of each eco-hydrology index respectively.Based on the index weights,a cascaded reservoir ecological scheduling model was constructed considering fish breeding needs.Based on the adaptive artificial fish swarm algorithm and the basic artificial fish swarm algorithm,the basic verification of the ecological dispatching model of the cascade reservoir is carried out,and the calculation results and the improvement degree of each index are further analyzed,and the rationality and feasibility of the dispatching model are verified by comparing the actual dispatching results..(2)Response analysis of fish reproduction to the effect of ecological dispatch.Based on the research on ecological regulation of cascade reservoirs considering fish breeding needs,combined with the influence of changes in water quality factors in the downstream of Yantan on fish reproduction since the water quantity regulation of the main stream of the Xijiang River during the fish breeding period,the Pearson correlation analysis method was used to analyze the effect indicators of fish reproduction and ecological regulation.Correlation and lag analysis were carried out to analyze the correlation between fish reproduction and various influencing factors,and the change of the correlation coefficient between each influencing factor and fish reproduction with the increase of lag days.Further,the generalized additive model and the generalized linear model were used to select the optimal model.Based on this,the generalized additive model was used to analyze the response changes of fish reproduction to various influencing factors,and the appropriate range of each influencing factor to satisfy fish reproduction was deduced.It is expected to provide a certain theoretical basis and decision-making support for meeting the needs of fish reproduction since the implementation of fish breeding season water regulation in the Xijiang River Basin.