Impact of Three Gorges reservoir operation with ahead impounding water on Acipenser sinensis spawning

This paper focuses on a study of the main spawning grounds of Acipenser sinensis in the reach from Gezhouba to Miaozui.A two-dimensional hydraulic model was solved with a finite-volume method and the flow field was simulated for normal impoundment scheme and ahead impoundment scheme.By combining this model with a physical habitat model and considering the spawning preference velocity,water depth and substratum,weighted usable area(WUA) of the habitat was calculated for different flow series and a relationship between WUA and flow was established.The results indicate that the ahead impoundment scheme is beneficial to the spawning and the flow of 13000-19000 m3/ s is optimal.This work provides a support to Acipenser sinensis protection and ecological operation of the Three Gorges reservoir.