水电站机组尾水区域鱼类分布及其对流场响应的初步观测OA

To better protect the fish resources in the tailwater area of hydropower stations,this study employs hydroacoustic cruising surveys to conduct observations on fish distribution and flow fields in the tailwater area in March 2024,aiming to explore the characteristics of fish distribution and their response patterns to flow fields.The results show that 60 and 55 valid fish signals were detected in the two surveys,respectively.When only Unit 6 was in operation,the average fish body length,maximum volume density,and average volume density were all higher than those when all 6 units were shut down.In terms of spatial distribution,fish schools were uniformly distributed along the tailwater outlets when the units were shut down,while they concentrated in the backwater area downstream of the sill at the tailwater outlet during unit operation.For vertical dis-tribution,fish present a greater tendency to inhabit the deep water layer below 5 m(accounting for 85.5％)under the operat-ing condition.Flow field analysis indicates that unit operation altered the regional flow velocity gradient and circulation structure,and fish exhibited significant behavioral responses by adjusting their habitat positions and water layer selection to adapt to the changes in flow fields.The research results provide basic data for the optimization of hydropower station opera-tion and the protection of fish in the tailwater area.