An Analysis of Partial-Depth, Floating, Impermeable Guidance Structures for Downstream Fish Passage at Hydroelectric Facilities

A floating impermeable guidance structure (FIGS) for downstream fish passage is constructed as a series of partial-depth panels anchored across a river channel, reservoir, or power channel. If guidance is successful, the fish will avoid entrance to a dangerous intake structure (i.e. turbine intakes) while passing from the upstream to downstream end of a dam through a safer passage route (i.e. the bypass). To evaluate the flow field immediately upstream of a FIGS, a parameterized CFD model of an idealized power channel was constructed in ANSYS Fluent v. 14.5. The design parameters investigated were the angle and depth of the FIGS and the average approach velocity in the power channel. Key findings indicate that a FIGS set at a small angle and deep enough such that the Effective Guidance Depth of the FIGS is greater than the expected
vertical distribution of fish approaching the structure will perform the best.