Experimental Investigation of Baffle Configurations for Enhancing Hydraulic Performance in Fishways

Fishways are essential hydraulic structures that enable fish to overcome natural and artificial barriers, ensuring ecological connectivity in river systems. This study experimentally investigates the influence of baffle geometry and configuration on the hydraulic performance and biological suitability of pool-type fishways. Three laboratory models A10, A7, and A5 were constructed with varying baffle heights of 10, 7, and 5 cm, respectively, and tested under discharges ranging from 200 to 750 L·min⁻¹. Key hydraulic parameters, including flow depth, energy dissipation, and velocity distribution, were systematically measured and analyzed. Results revealed that Model A7 exhibited the highest mean energy dissipation (0.81) and strong vortex formation favorable for fish resting, while Model A10 maintained optimal flow uniformity and sufficient depth (average 0.363 m) across a wide discharge range. In contrast, Model A5 produced excessive turbulence and inadequate flow depth, reducing its ecological suitability. Overall, Model A10 demonstrated the most balanced performance between hydraulic efficiency and biological safety. These findings provide practical insights for optimizing fishway design, suggesting that moderate baffle heights and controlled slopes can effectively enhance fish passage efficiency and minimize physiological stress on aquatic species.