Hydrodynamic optimization of bilateral-symmetric multi-slot fishway

This study compares the hydrodynamic characteristics of the vertical-slot fishway (VSF), the original Bilateral-symmetric Multi-Slot Fishway (referred as BMSF-8 in the literature) and twelve modified Bilateral-symmetric Multi-Slot Fishways (i.e. BMSF-R1~BMSF-R12). Numerical results indicate that BMSF-R11 has the best hydrodynamic performance among all the fishways considered. For instance, the maximum time-averaged velocity is 2.03~2.08 m s-1 in VSF, 1.36~1.45 m s-1 in BMSF-8, and 1.13~1.15 m s-1 in BMSF-R11. The maximum time-averaged turbulent kinetic energy is 0.186~0.214 m2 s-2 in VSF, 0.109~0.141 m2 s-2 in BMSF-8, and 0.073~0.083 m2 s-2 in BMSF-R11. The region with the time-averaged velocity less than 1.00 m s-1 accounts for 71.9%~72.3% in VSF, 77.7%~81.5% in BMSF-8, and 90.1%~92.1% in BMSF-R11. The region with the time-averaged turbulent kinetic energy less than 0.05 m2 s-2 accounts for 60.3%~64.8% in VSF, 63.5%~77.2% in BMSF-8, and 97.0%~97.9% in BMSF-R11. Consequently, the recommended BMSF-R11 serves as a good multi-species fishway, suitable for both large-sized strong-swimming fishes and small-sized weak-swimming fishes.