A Novel V‐Shaped Multi‐Slot Fishway: Enhancing Upstream Migration Efficiency for Weaker Swimmers and Supporting Aquatic Biodiversity Restoration

ABSTRACT Traditional vertical slot fishways (VSFs), designed primarily for larger fish species like salmon, often fail to accommodate smaller, weaker‐swimming species, leading to low passage efficiency. To address this limitation, a novel V‐shaped multi‐slot fishway (VMSF) is proposed, offering improved passability for weaker swimmers. A comprehensive comparison between the VMSF and the VSF was conducted, focusing on flow field topology, operational flow rate and key hydraulic performance indicators. Meanwhile, to further optimize the VMSF structure, the design was analysed under different variations of V‐shaped baffle angles and positions. Among the eight VMSF designs analysed at a water depth of 1.8 m, VMSF‐2 was identified as the optimal solution. Compared to the VSF, VMSF‐2 reduced the flow rate by 33.46% and decreased volume‐ and time‐averaged velocity, turbulent kinetic energy, Reynolds shear stress, turbulent dissipation rate and turbulence intensity by 8.65%, 26.32%, 48.77%, 12.20% and 10.76%, respectively. Additionally, under four different operating conditions, VMSF‐2 showed significant improvements in overall performance. This optimized design reduces fish fatigue, diversifies migratory routes and significantly improves both fish passage efficiency and hydraulic performance.