Pool-type Fishway Research Articles

Modelling of Pool-Type Fishways Flows: Efficiency and Scale Effects Assessment

In this study, the 3D numerical modelling of flow in a pool-type fishway with bottom orifices was performed using computational fluid dynamics (CFD) software (FLOW-3D®). Numerical results were compared with experimental data obtained from acoustic Doppler velocimetry (ADV) and particle image velocimetry (PIV) measurements. Several hydrodynamic variables that influence fishways efficiencies, such as flow depths, flow patterns, water velocity, turbulent kinetic energy, Reynolds normal stresses, and Reynolds shear stress parallel to the bottom component, were qualitatively and quantitatively compared. The numerical model accurately reproduced the complex flow field, showing an overall good agreement between the numerical model predictions and the experimental data for the analysed variables. The importance of performing a numerical model validation for all the parameters under analyses was highlighted. Additionally, scaling effects were analysed by running an upscaled numerical model of the prototype fishway. The model performed with similar accuracy for both physical model and prototype dimensions with no evidence of scale effects. The present study concludes that CFD models (namely FLOW-3D®) may be used as an adequate and efficient design and analysis tool for new pool-type fishways geometries, reducing and complementing physical model testing.

Pool-Type Fishway Design for a Potamodromous Cyprinid in the Iberian Peninsula: The Iberian Barbel—Synthesis and Future Directions

The Iberian barbel (Luciobarbus bocagei) is one of the most common cyprinids in the Iberian Peninsula, whose migratory routes are often hampered by anthropogenic barriers. Fishways might be an effective mitigation measure if they integrate designed operational characteristics that account for the biomechanical requirements of this species. Understanding the flow conditions inside the fishway, and how barbel responds to the hydrodynamics of the flow is imperative to improve free migratory routes with minimum energetic cost associated. Herein, we analyze and synthesize the main findings of research on pool-type fishways for upstream passage of the Iberian barbel and derive recommendations of design criteria for pool-type fishways for this species and others of similar biomechanics capacities. Ultimately, we identify research needs to improve upstream passage of this species.

Pool-type fishway on the Sembayat barrage

This paper presents the hydraulic flow system in a fishway to simulate the flow of a pool-type fishway. A fishway is a waterway to allow some fish species to pass by a human-made obstruction in a river or stream. The construction on the river, which has no fishway, will impact the river ecosystem balance. The purpose of this research is to give an alternative to reduce negative effect on the river ecosystem because of the obstruction. The velocimeter and the flow type in fishway must be able to be passed by the fish. In a kind of the pool-type fishway, there is an orifice in the bottom that has a potential supercritical flow before it becomes subcritical flow. The purpose of this experiment is to identify the surge in the pools of the fishway. The physical model of the pool-type fishway in Sembayat Barrage, Gresik was created to analyse the hydraulic condition of the flow in the fishway structure. The velocity has a greater value than the permissible velocity of the fish, and thus several fishways are not able to function optimally because the fish refuse to swim through the fishway. From the results of the study, it can be concluded that the velocity can be reduced by adding baffles at the downstream part of the orifice.

Artificial fishways and their performances in China’s regulated river systems: a historical synthesis

China‘s rivers are highly regulated. The biodiversity and ecosystems of these rivers are threatened by barriers restricting fish movements for reproduction and foraging. To overcome this challenge, several fishways are built across the country. However, the status of fishways is not well investigated. Based on published articles, library archives, and public interviews, we have identified type, location and period of fishways construction. We have then evaluated the performance of fishways. Up until 2018, the total number of fishways in China was estimated to be 150, where 82 of them have been analyzed in this study. The pool-type fishway is the most dominant fishway type, which accounts for 83%. The slope pattern of the 49 pool-type fishways shows that the slope tends to decrease with increasing lifting height. The performance of the fishways was best observed by the successful crossing of different species of fish in Yangtze and Pearl River basins when the slopes were 1:63–1:95. When many dams in China are already facing critical challenges for adopting the right type of fishways, the pool-type fishways with variable adjustments of slopes could be an effective option for successful fish migrations in regulated river systems.

The use of behavioural metrics to evaluate fishway efficiency

AbstractFishways are installed worldwide to facilitate accessibility to functional habitats and to increase the ecological continuity of rivers. Their evaluations are increasing, but complete studies in the field with wild individuals are still scarce. In the lower Bocq River (Belgium), a pool type fishway was installed in 2011. A combined passive‐integrated‐transponder‐tag and radio‐telemetry system was designed and installed downstream of the dam and in the fishway to analyse fine‐scale individual fish behaviour. Three fish species (brown trout, European grayling, and barbel) were captured in the river; n = 125 fish were tagged and released downstream of the fishway. Behavioural metrics were proposed and used in order to attain a comprehensive view on the efficiency of the fishway, including attraction and entrance efficiency, searching and passage delays, and overall and adjusted passage efficiency. The results indicate a major problem in terms of attraction efficiency (48.9% for the trout, 20.5% for the grayling, and 41.2% for the barbel) and time to find the entrance of the fishway (mean 65.1 hr for the trout and 538.9 hr for the grayling). For fish that succeed to approach the entrance of the fishway, the passage efficiency was 86.9% for the trout, 55.5% for the grayling, and 7.1% for the barbel. The time taken to cross the structure was reasonable for the salmonids (mean < 1.5 hr for trout and grayling) but very long (21 hr) for the barbel. Our results underline the necessity of a holistic approach to evaluate fishway efficiency using precise comprehensive metrics and hydraulic characterization.

Comparative analysis of particle image velocimetry and acoustic Doppler velocimetry in relation to a pool-type fishway flow

ABSTRACTParticle image velocimetry (PIV) and acoustic Doppler velocimetry (ADV) were used in a pool-type fishway with bottom orifices to measure velocity at several locations in planes parallel to the bottom and to the sidewalls. Estimates of parameters that influence fishways efficiency, such as water velocity and turbulent kinetic energy (TKE), were compared. Differences in temporal and spatial resolutions of both techniques were assessed. In-plane mean velocity magnitude showed very good agreement between both instruments, with raw measurements presenting similar values of the square of the sample correlation coefficient (R2) and the refined index of agreement (dr) as post-processed ones. The in-plane TKE agreement between both instruments greatly improved with post-processing, with R2 and dr ranging from 0.92 to 0.99, whereas raw values were lower (0.49–0.85). Nonetheless, further investigation is needed on the efficiency of the denoising method at points with sharp velocity gradients in the horizontal velocity components (perpendicular to ADV axis components).

Experimental Flow Analysis of a Pool-Type Fishway Using Velocity Fields from Reduced Model and Prototype

This work deals with an experimental flow analysis of the first Brazilian vertical slot fishway using flow velocity measurements obtained from the facility reduced model and prototype. A fishway reduced model at 1:20 scale is specially devised to evaluate the flow conditions in laboratory. The reduced model flow velocity fields are compared with those obtained from the measurements taken from the prototype to perform the model validation. The experimental flow velocity fields rendered in this work permit not only to analyze the fishway flow characteristics but also to evaluate feasible changes on vertical slot fishways capable of improving their efficiency.

Experimental Study on Hydraulic Characteristics of Pool-Type Fishway

Fishway is an effective engineering measure to keep the river longitudinal connectivity and maintain aquatic biodiversity. In this experiment, the pool-type fishway with asymmetric notches and orifices was studied, the ADV was employed to measure the velocity data in the pools, the flow velocity and flow regimes in the pools with the length of 0.5m, 0.6m and 0.7m at different measuring lines were analyzed. The results show that the maximum velocity is 0.35±0.025m/s in the three kinds of pools, and both the backflow region and the backflow velocities are correspondingly increased with the increasing length of the pool.

Pool-Type Fishways: Two Different Morpho-Ecological Cyprinid Species Facing Plunging and Streaming Flows

Fish are particularly sensitive to connectivity loss as their ability to reach spawning grounds is seriously affected. The most common way to circumvent a barrier to longitudinal connectivity, and to mitigate its impacts, is to implement a fish passage device. However, these structures are often non-effective for species with different morphological and ecological characteristics so there is a need to determine optimum dimensioning values and hydraulic parameters. The aim of this work is to study the behaviour and performance of two species with different ecological characteristics (Iberian barbel Luciobarbus bocagei–bottom oriented, and Iberian chub Squalius pyrenaicus–water column) in a full-scale experimental pool-type fishway that offers two different flow regimes–plunging and streaming. Results showed that both species passed through the surface notch more readily during streaming flow than during plunging flow. The surface oriented species used the surface notch more readily in streaming flow, and both species were more successful in moving upstream in streaming flow than in plunging flow. Streaming flow enhances upstream movement of both species, and seems the most suitable for fishways in river systems where a wide range of fish morpho-ecological traits are found.

Effect of flow regime hydraulics on passage performance of Iberian chub (Squalius pyrenaicus) (Günther, 1868) in an experimental pool-and-weir fishway

Dams and weirs strongly affect or inter- rupt the longitudinal connectivity of rivers, by limiting the movements of several fish species while altering and fragmenting habitats. Fishways, especially pool- type fishways, are used to diminish this impact by enabling fish to negotiate barriers. The aim of this work is to study the behaviour of a small-sized resident cyprinid fish, the Iberian chub—Squalius pyrenaicus (Gunther, 1868)—within a prototype of a pool-type fishway, equipped with both surface notches and bottom orifices, and experiencing two different flow regimes, plunging and streaming. Results show that the fish tended to be more successful in their upstream movements under streaming flow and that, for this regime, the surface notch was the preferred route for upstream movements. Flow velocity patterns corrob- orated the results, showing that the plunging flow regime may have driven fish downstream, while the streaming flow regime may have attracted fish upstream. The plunging flow also prevented access of this surface-oriented species to the surface notch, effectively reducing the area available for transport. Thus, the streaming flow regime can be a sound option for this and other small-sized species, as it enhances fish movements through the fishway.

Use of electromyogram telemetry to assess the behavior of the Iberian barbel (Luciobarbus bocagei Steindachner, 1864) in a pool-type fishway

Decline in fish species populations due to river regulation by dams and weirs promoted the development of fishways, which are becoming one of the most common measures for the restoration of connectivity in rivers. Fishways efficiency can be species specific and thus monitoring and evaluation, and subsequent adjustments to design and hydraulic features, are required to inform potential users prior to installation. In this study we tested the applicability of electromyogram telemetry to study the swimming behavior of a cyprinid potamodromous species, the Iberian barbel Luciobarbus bocagei Steindachner, 1864, in an experimental pool-type fishway. In total, 24 barbels were used in the experiment, 12 of which were tagged with EMG radio transmitters equipped with electrodes that register muscle activity, while the other 12 untagged fish were used as control. For tagged fish, a relationship between swimming speed and EMG telemetry signals was developed in a swimming tunnel, which was later used to assess barbels swimming behavior within the experimental fishway. Tagged fish exhibited high passage success and anaerobic burst swimming was only required to move through the submerged orifices of the fishway. Barbels spent successively less time when transversing the pools in the upstream direction. Measured hydraulic variables that were related with barbels’ swimming speed within the fishways were the water velocity, turbulent kinetic energy, turbulence intensity and, especially, the horizontal component of Reynolds shear stress, highlighting the importance of these parameters when designing pool-type fishways.

Effect of two flow regimes on the upstream movements of the Iberian barbel (Luciobarbus bocagei ) in an experimental pool-type fishway

Literature related to pool-type fishways has seen a recent upsurge of interest in the placement of instream structures for improving fish passage. However, there is still no information on how different flow regimes created by boulder placement have an influence on upstream fish movements. The main goal of this study was to assess the performance of two different flow regimes, characterized by the relative depth of flow (d/h), where d is the water depth and h is the height of artificial bottom substrata, in assisting fish passage in an experimental full-scale pool-type fishway. Two series of experiments consisting of 20 replicates each and representing distinct flow regimes created by boulder placement in the flume bottom – d/h > 4 (regime 1) and 1.3 < d/h < 4 (regime 2) – were carried out to analyse the proportion and timing of successful upstream movements of a potamodromous cyprinid, the Iberian barbel (Luciobarbus bocagei). Although no significant differences (P > 0.05) in passage success were observed between regimes (55% and 60%, respectively), fish transit time was significantly lower (P < 0.05) in regime 2 (mean ± SD: 2.6 ± 1.6 min.) than in regime 1 (7.1 ± 5.8 min.). The results of these experiments show that lower relative depths can be more beneficial to fish passage because they reduce the transit time for successful negotiation, thus providing a useful indication on how to improve fish passage through pool-type fishways.

Fish passage assessment at the most downstream barrier of the Ebro River (NE Iberian Peninsula)

Fish passage assessment at the most downstream barrier of the Ebro River (NE Iberian Peninsula) Fish passage at artificial barriers is necessary for the conservation of healthy fish stocks. The first barrier that migratory fish encounter when ascending the Ebro River is the Xerta Weir, where a pool-type fishway was constructed in 2008. From 2007 to 2010, boat electrofishing surveys were conducted in the Ebro River downstream of the Xerta Weir to assess the potential pool of species that could use the fishway. Nine native and 12 exotic species were captured, the latter comprising 62 % of the relative abundance and 70 % of the biomass. A combination of video recording, electrofishing and trapping was used to assess the effectiveness of the fishway in facilitating the passage of fish. Eight species were detected using the fishway, of which five were native (Liza ramada, Anguilla anguilla, Barbus graellsii, Gobio lozanoi and Salaria fluviatilis) and three exotic (Alburnus alburnus, Cyprinus catpio and Rutilus rutilus). Only L. ramada used the fishway in substantial numbers. The rate of fish passage was the highest from June to August and decreased afterwards. The effectiveness of the fishway might be lowered by amas of turbulence within the fishway and by distraction flows from a nearby hydropower station.

Cyprinid swimming behaviour in response to turbulent flow

Turbulence is a complex phenomenon which commonly occurs in river and fishway flows. It is a difficult subject to study, especially biologically, yet turbulence may affect fish movements and fish passage efficiency. Studies on quantifying fish responses to turbulence, particularly within fishways, are lacking. This study investigated the swimming behaviour of 140 adult Iberian barbel (Luciobarbus bocagei) of two size-classes (small fish: 15≤TL<25cm, large fish: 25<TL≤35cm) under turbulent flow conditions created by three submerged orifice arrangements in an experimental pool-type fishway: (i) offset orifices, (ii) straight orifices and (iii) straight orifices with a deflector bar of 0.5bo located at 0.2L from the inlet orifices, where bo is the width of the square orifices ranging from 0.18 to 0.23m and L is the pool length (1.90m). Water velocity and turbulence (turbulent kinetic energy, Reynolds shear stress, turbulence intensity and eddy size) were characterized using a 3D Acoustic Doppler Velocimeter (ADV) and were related with fish swimming behaviour. The influence of turbulent flow on the swimming behaviour of barbel was assessed through the number of successful fish passage attempts and associated passage times. The amount of time fish spent in a certain cell of the pool (transit time) was measured and related to hydraulic conditions. The highest rates of passage and the corresponding lowest times were found in experiments conducted with offset orifices. Although size-related behavioural responses to turbulence were observed, Reynolds shear stress appeared as one of the most important turbulence descriptors explaining fish transit time for both size-classes in experiments conducted with offset and straight orifices; furthermore, swimming behaviour of larger fish was found to be strongly affected by the eddies created, in particular by those of similar size to fish total length, which were mainly found in straight orifices with a deflector bar arrangement. The results provide valuable insights on barbel swimming behavioural responses to turbulence, which may help engineers and biologists to develop effective systems for the passage of this species and others with similar biomechanical capacities.

Caracterização de Velocidades Médias e Padrões de Turbulência do Escoamento em Escadas para Peixes por Bacias Sucessivas com Orifícios de Fundo

Dam construction and its barrier effects represent the most significant disturbances caused by man-made activities in rivers, interfering with fish movements and causing serious constraints to the reproduction of migratory species. In an attempt to help species progress upstream, many dams include fish passes to help the species in their life cycles maintaining their free movement. This paper evaluates flow in a pool-type fishway equipped with bottom notches. The study was conducted in a physical model. Velocity measurements were performed in a pool of a model with an Acoustic Doppler Velocimeter (ADV). Based on velocity data dimensional mean flow and turbulence structure were defined by turbulent kinetic energy and Reynolds’ shear stress

Selection of Iberian barbelBarbus bocagei(Steindachner, 1864) for orifices and notches upon different hydraulic configurations in an experimental pool-type fishway

Summary Trends in fish passage studies are increasingly moving towards a holistic approach in considering the movements of a wide range of fish species and other aquatic fauna. In this context, it is important to consider not only salmonids and other game species, but also coarse species such as cyprinids. Moreover, knowledge of their behaviour when confronted with fishways is limited, particularly their upstream movements with regard to different hydraulic configurations. To address this deficit, research was conducted in an indoor full-scale pool-type fishway to assess the cyprinid Iberian barbel Barbus bocagei (Steindachner, 1864) response to the simultaneous presence of submerged orifices and surface notches with adjustable dimensions in association with two different flow regimes over the notches, i.e. plunging and streaming. Overall, orifices (76%) were the clear choice to negotiate the fishway. When the flow was in the plunging mode, a significantly higher proportion of fish selected the orifices to move upstream, but the proportions were equal during the streaming mode. The time taken to enter the fishway differed significantly according to the chosen discharge device and was lower for submerged orifices (52 s to 35 min.). The present study identified key factors in Iberian barbel upstream movements, which provide direct applications to future fishway designs for this species.

Numerical flow simulation of pool-type fishways: new ways with well-known tools

Fish passage structures are built to restore the connectivity of rivers and allow the migration of aquatic fauna. In order to assess the functioning of a pool-type fishway, it is necessary, inter alia, to possess detailed knowledge of its flow structure, since observations of fishways, and in particular of the visible water surface, can only provide a rough idea of the actual conditions inside the pools. Numerical simulation has been used for many years to support engineering sciences. Especially, the modeling of flow processes in hydraulic machines can, on the one hand, help avoid major problems during the design stage of fish passage structures and, on the other, improve the structure’s hydraulic performance. To this end, two diploma theses within the framework of a research project of the local energy supplier Energie Baden-Wurttemberg AG (EnBW) employed modeling tools for 3D flow simulation, primarily for pool-slot fishways (PSF), and for traditional vertical slot fishways (VSF).

AQUATIC INSECTS IN FISHWAY BIOTOPE ON AONO DAM SITE

Aquatic insects were surveyed to evaluate a biotope of Aono dam fishway ecologically. The Aono dam is located on the Aono river, a tributary of the Muko river which flows through Hyogo Prefecture, Japan. The fishway consists of pool-type fishway, riffle and pool sequences and etc. Aquatic insects were sampled by picking up surface bed materials in about 0.09m2 quadrat and washing adhered materials out. Sampled aquatic insects were identified to genera and individual numbers were counted for each genus. The genera and their individual numbers were examined in relation to hydraulic and bed conditions. EPT, Shannon Diversity Index and etc. were calculated for each sample. Most sampled insects belongs to genera which have tolerance to organic pollutions and usually live in lower reaches. Algae and mud which are supposed to come from the dam reservoir strongly influence spatial distribution of the genera of insects.

FLOW ANALYSIS IN A POOL AND WEIR TYPE FISHWAY

This paper presents 2-dimensional flow characteristics in a pool type fishway by using the VOF method. The fishway with 5 pools is treated as an object of the study. Considering the flow pattern of a pool type fishway, the analytical region is divided into 3 parts, which are the upstream part, the middle part and the downstream part of the fishway. As a result, the proposed method is able to reproduce the flow in the pool type fishway with many pools. And it is also clarified that the down stream water level condition plays a very important roll to design the pool type fishway.