Retrofitting of Existing Bar Racks with Electrodes for Fish Protection—An Experimental Study Assessing the Effectiveness for a Pilot Site

Downstream-migrating fish in rivers tend to follow the main current, and are in danger of swimming through the turbines at run-of-river hydropower plants, possibly causing high mortality rates. To avoid these losses, fish must be prevented from entering the turbines. Most existing vertical bar rack...

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Bibliographic Details
Published in:Water (Basel) 2022-03, Vol.14 (6), p.850
Main Authors: Haug, Jonas, Auer, Stefan, Frees, Calvin, Brinkmeier, Barbara, Tutzer, Ruben, Hayes, Daniel S., Aufleger, Markus
Format: Article
Language:English
Subjects:
Analysis
Animal behavior
Barriers
Behavior
Electric fields
Electrodes
Fish barriers
Fish ladders
Fish migration
Fishes
Fishways
Flow velocity
Health aspects
Hydraulics
Hydroelectric plants
Hydroelectric power
Hydroelectric power plants
Mortality
Protection and preservation
Racks
Retrofitting
Rivers
Swimming
Turbines
Water-power
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Summary:Downstream-migrating fish in rivers tend to follow the main current, and are in danger of swimming through the turbines at run-of-river hydropower plants, possibly causing high mortality rates. To avoid these losses, fish must be prevented from entering the turbines. Most existing vertical bar rack systems (used for turbine protection) however usually do not ensure proper fish protection due to large bar spacings. FishProtector technology enables the retrofitting of existing bar racks (i.e., the mechanical barrier) with additional electrodes to create a hybrid barrier. The induced electric field in the water aims to create a behavioral barrier to prevent fish passage through the bar rack. In this study, ethohydraulic experiments to investigate the effect of such a behavioral barrier on fish were performed. In detail, the fish-protection rate at a bar rack with a bar spacing of 30 mm was tested in five different scenarios: (i) a bar rack without electrodes (reference), and four electrified setups with electrode spacings of (ii) 80 mm, (iii) 120 mm, (iv) 160 mm, and (v) 200 mm. A flow velocity of 0.23 m/s was chosen to replicate the situation at a planned pilot site. The study was conducted in an outdoor laboratory flume using small fish of several local riverine species, mostly cyprinids and minnows. The results show that the mean fish-protection rate in the experiments could be increased from 62% in the reference setup up to 96% in the electrified setups.
ISSN:2073-4441
2073-4441
DOI:10.3390/w14060850