Ecological operation experiment and effect analysis of Liyuan Hydropower Station in middle reaches of Jinsha River

Ecological operation of hydropower projects which can fulfill the ecological requirements in the breeding season of important aquatic organisms is an important measure to implement the great protection of the Changjiang River at present.The ecological operation experiment to promote the natural reproduction of endemic fishes such as Leptobotia elongata and Coreius guichenoti was carried out from 2020 to 2021 in Liyuan Hydropower Station in the middle of Jinsha River.The early fish resources and hydrological environmental elements were observed simultaneously in a sampling site downstream of the dam, in order to grasp the response of fish natural reproduction to ecological operation, and preliminary evaluate the implementation effect of ecological regulation.The results showed that the density of fish eggs had a positive response relationship with the downstream dam water temperature and the outflow.The spawning activities of Leptobotia elongata,Coreius guichenoti,Sinibotia superciliaris were monitored during ecological operation period.Condition of water temperature and flow rate were considered as the main factors affecting ecological operation in two years.Based on the results, some suggestions for optimizing the Liyuan ecological operation were put forward.Under the background of the decline of endemic fish resources and the shrinking of suitable habitats in the middle reaches of Jinsha River, it was suggested to urgently start the joint ecological operation of cascade hydropower stations such as Liyuan and Ahai hydropower stations, to extend the length of flowing water section to ensure the reproduction and habitat of endemic fish.