Design and study of bidirectional fish passage facilities at Yanglin Sluice in Huayang River Flood Retention Area

To reduce the seasonal obstruction to migratory fish caused by disconnection within the Huayang River lake group, we developed a bidirectional fish passage system. Based on field investigations into fish species and their ecological behavior in the Huayang River Flood Retention Area, this study identified the key and secondary target fish species and their respective migration seasons. Through comparative analysis of the swimming capabilities of seven representative species, a design scheme that fishways directing to the river and lake arranged on the left and right banks of the Yanglin Sluice was proposed. In-depth research was conducted for fishway entrances and exits, pool structures and baffles. Numerical simulations were employed to analyze hydraulic performance. The results showed a clear mainstream flow within the pools, with inlet and outlet water depths exceeded 1.0 m. Flow velocities at vertical sloted ranged from 0.48 m/s to 1.00 m/s, and inlet velocities ranged from 0.15 m/s to 0.20 m/s, which was suitable for upstream migration of main and secondary target species. The proposed fishway demonstrates effective fish attraction and passage performance.