Safe Passage of American Eel Through a Novel Hydropower Turbine

August 17, 2022

"Safe Passage of American Eel Through a Novel Hydropower Turbine," by Sterling Watson, Abraham Schneider, Leon Santen, Katherine A. Deters, Robert Mueller, Brett Pflugrath, John Stephenson, and Z. Daniel Deng.

The effects of downstream passage through a novel turbine designed for fish safety, the Restoration Hydro Turbine (RHT), were studied for American Eel Anguilla rostrata in a recirculating turbine test facility. A 55 cm diameter RHT was operated under 10 m of hydraulic head and 667 revolutions per minute. A total of 131 eels were passed through the turbine, and 43 eels were used as experimental controls (length 33.9 cm–65.5 cm). High-speed video of passage through the runner region was captured for 89% of turbine-passed eels, and injury and behavioral effects were recorded immediately before and after passage, as well as after a 48-hour hold period. A subset of 37 eels was additionally examined with X-ray imaging for internal injuries. The 48-hour survival rate for both treatment and control groups was 100%, with no major internal or external injuries present after the hold period. This result is a substantial improvement over eel survival rates through conventional Kaplan and Francis turbines, which may range from 40% to 95%, and suggests that hydropower turbines designed for safe downstream fish passage could be implemented without major impacts to eels.

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