Modeling of Flow in a Weir and Pool Fishway With Orifices for Optimizing the Fishway Design

Fishways that facilitate fish to migrate upstream by passing the obstructions such as dams built across waterways are given increased attention with respect to their efficiency and cost. A computational fluid dynamics (CFD) model, ANSYS CFX 17.2 software was used to investigate the three-dimensional flow in a weir and pool fishway. The model results were verified using published data and measurements obtained by a laboratory experiment. The model was then applied to compute the water depth, velocity, turbulent kinetic energy and energy dissipation rate distributions of a weir, and pool type fishway under different slopes. Economic design of steeper weir and pool type fishways with high fishway efficiency is feasible by controlling the depth at the downstream of the fishway.