Fish guidance structures: hydraulic performance and fish guidance efficiencies

Albayrak, Ismail; Boes, Robert M.; Kriewitz-Byun, Carl Robert; Peter, Armin; Tullis, Blake P.

doi:10.1080/24705357.2019.1677181

Cited by 42 publications

(80 citation statements)

References 14 publications

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“…Top and bottom overlays are part of an HBR design, which can significantly increase head losses. Despite this, laboratory studies indicate higher guidance for bottom-and surface-oriented fish [9,27]. Additionally, overlays improve the routing of driftwood and sediments towards the bypass [1].…”

Section: Fish Protectionmentioning

confidence: 99%

Head Losses of Horizontal Bar Racks as Fish Guidance Structures

Meister

Fuchs

Beck

et al. 2020

Water

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Horizontal bar racks have been used as trash racks at hydropower plants since the 1920s. With the installation of the first horizontal bar rack bypass system at a hydropower plant as a downstream fish passage facility in 2006, these racks rapidly gained importance as fish protection measures. Since then, they have been installed at more than 100 small-to medium-sized hydropower plants in Europe. Despite the large number of installed racks, systematic investigations of the head losses and velocity fields were missing. On the basis of detailed hydraulic experimentation with a large number of rack parameters and including up-to-date foil-shaped bars, the layout of horizontal bar racks and their hydraulic performance were assessed in the current study. This paper reports the results of the rack head loss investigation, whereas the accompanying paper entitled Velocity Fields at Horizontal Bar Racks as Fish Guidance Structures focuses on the up-and downstream velocity fields. By applying foil-shaped bars instead of rectangular bars, the loss coefficient was reduced by more than 40%, depending on the rack configuration. Bottom and top overlays are used to increase the guidance efficiency for fish, sediments, and floating debris. However, the altered flow field results in increased head losses. A new set of equations is proposed to predict head losses for current horizontal bar racks, including overlays for various hydropower plant layouts. The predictions are compared to literature data.

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Section: Fish Protectionmentioning

confidence: 99%

Head Losses of Horizontal Bar Racks as Fish Guidance Structures

Meister

Fuchs

Beck

et al. 2020

Water

Self Cite

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“…Considering FGS in real-scale numerical 3D-simulations of HPP is usually restricted to a smaller section, because the required grid resolution to resolve the whole FGS would lead to very large computing time making the conceptual approach inexpedient. Therefore, the hydraulic conditions of the present state without FGS are used as a reference, while the effects of FGS on the flow fields and on rack-near fish behavior known from detailed etho-hydraulic modelling [6,7,10,13,17,19,20,[44][45][46][47] are taken into account separately in the assessment phase, see Section 2.3.…”

Section: Hydrologic and Hydraulic Conditionsmentioning

confidence: 99%

“…Of primary importance are the hydraulic cues caused by the rack bars, i.e., the turbulent zones and flow separation along the rack edges [16], triggering an avoidance reaction in fish. These turbulent structures cause only a few fish to swim through the FGS [10,17]. However, the avoidance reaction decreases with increasing bar spacing [12].…”

mentioning

confidence: 99%

“…However, the avoidance reaction decreases with increasing bar spacing [12]. In fact, two fish species-specific reaction patterns could be observed in ethohydraulic experiments [10,17]. Some species, such as barbel, brown trout, and eel show investigative behavior and do not avoid rack contact.…”

mentioning

confidence: 99%

“…In addition to the classical bar rack, there exist further developments that are not arranged orthogonally to the rack axis, such as those with straight (Modified Bar Rack, MBR [10,17]) or curved bar cross-section shapes (Curved Bar Rack [18][19][20]). First investigations of this FGS type show a lower flow deflection and more symmetric flow field in the tailwater as well as lower hydraulic losses compared to conventional FGS.…”

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confidence: 99%

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Conceptual Approach for Positioning of Fish Guidance Structures Using CFD and Expert Knowledge

et al. 2019

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The longitudinal connectivity of many rivers is interrupted by man-made barriers preventing the up- and downstream migration of fishes. For example, dams, weirs, and hydropower plants (HPP) are insuperable obstructions for upstream migration if no special measures like fish passes are put into effect. While upstream fishways have been implemented successfully and are still being optimized, the focus of current research is more and more on effective fish protection and guiding devices for downstream migration. According to current knowledge fish guidance structures (FGS) have a high potential in supporting the downstream migration by leading fishes to a bypass as an alternative to turbine passage. This work presents a structured and straightforward approach for the evaluation of potential locations of FGS combining traditional dimensioning principles with computational fluid dynamics (CFD) and novel findings from etho-hydraulic research. The approach is based on three key aspects: fish fauna, structural conditions, and hydraulic conditions, and includes three assessment criteria, which are used in an iterative process to define potential FGS locations. The hydraulic conditions can be investigated by means of hydrodynamic 3D simulations and evaluated at cross sections of potential FGS positions. Considering fundamentals of fish biology and ethology allows for rating of the flow conditions and thus for a suitability assessment of various locations. The advantage of the proposed procedure is the possibility to assess FGS configurations without implementing the FGS in the numerical model, thus limiting the computational expense. Furthermore, the implementation of various operation conditions is straightforward. The conceptual approach is illustrated and discussed by means of a case study.

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Experimental evaluation of louver guidance efficiency for green sturgeon (Acipenser medirostris)

Steel

Nguyen

Cocherell

et al. 2022

River Research & Apps

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Throughout the world, louver‐bypass systems are a common method for fish protection at water diversion sites. Their performance has been evaluated for pelagic, strong‐swimming teleost fishes, but limited information exists regarding the effectiveness of louvers for guiding sturgeon, despite being a globally threatened taxon. This study used controlled laboratory experiments to quantify louver efficiency for juvenile green sturgeon under a range of conditions. Fish guidance efficiency was influenced most strongly by fish size and approach velocity, with poor efficiency for small fish at high velocities. Low velocities and, to a lesser extent, daylight conditions allowed a greater proportion of fish to remain upstream of the louver at all sizes. High velocities resulted in the greatest contact rate between the sturgeon and louver face. Louvers can be effective for benthic, weak‐swimming fish, but site‐ and species‐specific needs should always be considered in the development or operation of a louver guidance system.

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Fish guidance structures: hydraulic performance and fish guidance efficiencies

Cited by 42 publications

References 14 publications

Head Losses of Horizontal Bar Racks as Fish Guidance Structures

Head Losses of Horizontal Bar Racks as Fish Guidance Structures

Conceptual Approach for Positioning of Fish Guidance Structures Using CFD and Expert Knowledge

Experimental evaluation of louver guidance efficiency for green sturgeon (Acipenser medirostris)

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