The Fishprotector - An Integral Fish Protection System

The potential of hydropower turbines to cause injury or mortality to fish is a concern. To reduce this risk, engineers have begun to develop a conically arranged, cantilevered electrified bar rack (Center Sender). This device is proposed to be mounted within the intake of a turbine, guiding downstream-passing fish towards the center of the turbine where blade velocities are lower and blades are thicker, likely reducing the potential for fish to be injured. A simplified version was installed in a flume for testing with Rainbow trout (Oncorhynchus mykiss) while examining several parameters such as electrification, bar spacing, bar angle, and water velocity. The most effective settings were observed to be a water velocity of 1.0 m s−1 with all bars installed at an angle of 40° with electrification on. Other combinations were still effective but had varying results. A minimal proportion (2.3%) of fish passed at lower velocities with bars electrified and mounted at 20°, suggesting that while it functions well as a guidance device in high-velocity conditions, it performs better as a barrier at lower velocities. The study suggests that the Center Sender has promising potential for reducing the harmful effects of hydropower turbines on fish populations by guiding them away from stressors. Further research is needed, but current results encourage its potential use in hydropower operations.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Examination of an Electrified Bar Rack Fish Guidance Device for Hydropower Turbines

Pflugrath,

Watson,

Haug

et al. 2023

“…There are different types of FishProtectors in terms of spatial arrangement, electrodes used (steel cables or bars), and cleaning methods used. The hybrid barrier Flexible FishProtector consists of horizontally tensioned steel cables (physical barrier) that are simultaneously used as electrodes and surrounded by a moderate pulsating electric field (behavioral barrier) [22][23][24]. The pulsed electric field is created using the Neptun fish guidance and deterrence system (Procom System S.A., Wrocław, Poland) [25].…”

Section: Introductionmentioning

confidence: 99%

A Physical and Behavioral Barrier for Enhancing Fish Downstream Migration at Hydropower Dams: The Flexible FishProtector

Tutzer

Röck

Walde

et al. 2022

Self Cite

Fish protection at hydropower plants is important for the sustainability of hosting ecosystems and the acceptance of hydropower. On their way downstream, fish are exposed to hydropower plants and various related negative effects, ranging from a delay in downstream movement to being injured or killed by a turbine. Understanding the behavior of fish in close proximity to protection devices is essential in order to establish efficient fish protection facilities. In this study, physical (horizontal steel cables) and behavioral barriers (electric field) for fish protection were developed (Flexible FishProtector) and their effectiveness was investigated. The behavior of brown trout (Salmo trutta fario), rainbow trout (Oncorhynchus mykiss), grayling (Thymallus thymallus) and chub (Squalius cephalus) at the Flexible FishProtector was analyzed using video evaluation. The experimental setup was a non-scaled section model of a runoff river power plant. The used electric field induced a flight reaction at a corresponding distance to the Flexible FishProtector that significantly increased the protection rate. Furthermore, an increase in guiding efficiency was achieved with the use of a physical as well as a physical and behavioral barrier, supporting safe downstream migration with the narrower cable clearance (30 mm versus 60 mm).

“…If the stimulus-triggering field strength is exceeded, an escape reaction in an upstream direction follows. This escape reaction is usually carried out by only a few centimeters to decimeters [36]. Another cautious approach follows.…”

Section: Introductionmentioning

confidence: 99%

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

Haug

Auer

Frees

et al. 2022

Self Cite

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.