Review of downstream fish passage and protection technology: Evaluations and effectiveness

Publication Date



Prepared by Alden Research Laboratory, Holden MA



downstream fish passage, fish passage, protection, intake, fish protection, survey, design, engineering, guidance, sound, high frequency, clupeids, shad, herring, strobe light, salmonids, bubble curtain, curtain, turbulent, flow velocities, hydro projects, turbulence, barriers, diversion, structures, high velocity, Eicher screen, modular inclined screen, inclined screen, screens, survival, surface bypass, bypass, efficiency, barrier nets, louvers

Report number

Report No. TR-111517


The need for effective fish passage and protection at water intakes is an important issue confronting industry and resource agency professionals throughout the world. Project owners often are required to install and evaluate protection devices to meet regulatory requirements that are associated with operating licenses and permits. There is a wide array of technologies that currently are available for use at water intakes. The goal of this report was to present information from a comprehensive review of recent studies that have evaluated the effectiveness of existing and emerging fish protection and passage technologies designed for application at water intakes. A literature search and a survey of industry and resource agency professionals were conducted to identify available literature describing the application and evaluation of passage and protection technologies. All relevant reports and publications were reviewed and a summary of project design, study methods, and effectiveness results was prepared.Available fish passage and protection technologies are diverse and vary widely with respect to biological and engineering criteria. Behavioural guidance technologies (e.g., lights and sound systems) continue to be studied extensively. However, the use of high-frequency sound to repel clupeids (shad and herring) is the only behavioural technology that has been accepted as a proven technology. Strobe lights continue to demonstrate potential for successful application based on results from controlled experiments (i.e., cage tests), but systems that have been evaluated at field sites have not demonstrated consistently high levels of effectiveness. Infrasound is an emerging technology that has been tested in controlled experiments and during some field evaluations. The ability of infrasound to repel salmonids has been demonstrated inseveral small-scale studies, but operational constraints and mixed results to date make the future use of infrasound uncertain. Air bubble curtains were examined during two field studies at Midwestern hydro sites. A new concept involving the use of turbulent surface water and increased flow velocities has been proposed and limited testing with a current inducer device has been evaluated at small New England hydro projects. Further development of the surface turbulence concept and rigorous laboratory and field testing are required before viability of such technologies are determined.Screening systems used as barriers and/or diversion structures have been widely applied.Available screening technologies continue to be evaluated to improve the effectiveness of installed systems. Relatively new screening technologies that are gaining acceptance are the high-velocity Eicher screen and Modular Inclined Screen (MIS). Modifications to traveling water screens also have been made, resulting in greater survival of impinged fish at cooling water intakes. Bar racks (perpendicular and angled to the flow) have been prescribed at a large number of FERC-licensed projects (especially projects with anadromous species), often in conjunction with surface bypasses. The effectiveness of bar rack and bypass facilities has been mixed, with studies continuing to be conducted at many projects in attempts to improve bypass efficiency. Barrier nets and louvers both have been successfully applied during the last five years at several projects. These systems, however, have stringent biological and engineering requirements that can limit their use. http://www.epri.com

This document is currently not available here.