Type Of Fishway Research Articles

Escaping the dry: Native and non‐native fish outmigration from a receding floodplain following managed inundation

Abstract Many fish rely on being able to move between rivers and floodplains to fulfil key life history events, but river regulation has reduced floodplain inundation compromising these connections and causing the loss of ecosystem function more generally. Managed inundations are being trialled in some systems as a solution, whereby engineered floods using built infrastructure, such as floodplain regulators, are used to deliver water to inundate floodplains. However, the use of managed inundations is still in early stages and their outcomes for native fish have been rarely assessed. We present the results from a series of investigations assessing the effectiveness of two managed inundations on the native fish community in a large floodplain in south‐eastern Australia. We firstly described changes in fish assemblages in wetlands before and after managed inundation (Aim 1). We then examined which potential exits are used by golden perch, a highly mobile species that regularly moves between rivers and floodplains (Aim 2), and then assessed outmigration patterns of native and non‐native species during receding phase from one of the major golden perch exits via a fishlock (Aim 3). Finally, we conducted two experiments to test if it was possible to modify operation of the fishlock to maximise fish movement by varying the length of the operating cycle, or whether operation occurs during the day or night (Aim 4). We found that native fish dominated the catch in wetlands before drawdown of the managed inundation, but that non‐native species, especially young‐of‐year carp, dominated after the drawdown (Aim 1). Outmigrating golden perch left the floodplain wetlands in a variety of locations but predominantly through a fishlock, which is a type of fishway (Aim 2). At this fishlock, native fish outmigrated before and during the early phase of the floodplain recession, moving to permanent riverine habitats, whereas non‐native fish (mostly carp) tended to migrate later in the recession especially as water levels dropped (Aim 3). There were no substantive differences in the numbers and size of fish moving through the fishlock at different operating cycle times (Aim 4). While there were no differences in numbers of non‐native carp migrating during the day or night, native species (carp gudgeon and Australian smelt) were more common during the day. Our study has provided knowledge of the eco‐hydraulic mechanisms of fish movement, in relation to managed inundaitons. This knowledge can be applied to help water managers plan floodplain watering regimes in the Murray‐Darling Basin to benefit native fish, while potentially restricting movement of undesirable non‐native species such as carp. More broadly, our results improve current understanding of fish movement in relation to managed floodplain recession, which is critical given the increased use of such managed inundations, and the need for information to help design and evaluate them.

A large-scale passage evaluation for multiple fish species: Lessons from 82 fishways in lowland rivers and brooks

River networks worldwide are highly fragmented and this is particularly prevalent in the human-dominated lowland landscape of the Netherlands. Fishways function as measures to facilitate passage alongside barriers for fish communities and have been evaluated mostly in single case studies. We compared fish monitoring data of 82 fishways with data of fish observed in adjacent water stretches, conducting the first nationwide study on passage for the full spectrum of fish species present. In total, 35 out of 38 (92%) native species recorded in fishways' surroundings used fishways, while per fishway the median was 59% related to a variety of factors (fish behaviour, fishway type, monitoring design). The species using fishways most frequently were perch Perca fluviatilis (71/78 of fishways present), roach Rutilus rutilus (70/79) and gudgeon Gobio gobio (68/77). Logistic regression models showed the effect of monitoring duration and timing in detecting specific fish species ascending fishways. This large-scale analysis highlights the need to consider all native fish species during the design and monitoring of fishways. The obtained information from this study can be used by water managers for improving monitoring schemes and river connectivity which is an essential component for achieving the European Water Framework Directive goals.

Attraction and passage efficiency for salmonids and non‐salmonids based on fishway: A meta‐analysis approach

AbstractGlobally, fishways perform better when the target fish species are salmonids rather than non‐salmonids. In the past few decades, engineers and dam managers have attempted to identify an ideal fishway type that can fit all migratory orders. To determine a general rule for selecting fishway types, we classified all fish orders into two groups (salmonids and non‐salmonids) and analyzed the effect of different fishway types (i.e., nature‐like [NL], vertical slot [VS], pool and weir [PW], and denil [DL]) on upstream migration for both groups by conducting a meta‐analysis based on data from 64 studies of 76 fishways. The fishway performance was presented in terms of attraction efficiency (AE) and passage efficiency (PE). The results of a random‐effects model, including 257 and 299 estimates of AE and PE, respectively, showed fishway types only had a significant effect on AE for non‐salmonids. Technical fishways had a higher AE than NL fishways for salmonids, but were not applicable to non‐salmonids. The passage results of four fishway types indicated that the PW fishways exhibited the best performance for salmonids, but the poorest performance for non‐salmonids. Only DL fishways had a PE of over 50% for non‐salmonids, whereas all fishway types had that of over 60% for salmonids. Variations in the slope and length of VS fishways could significantly affect PE for both groups, however, the phenomenon for salmonids disappeared when merging all fishway types. Elevation changes had a significant effect only on the condition that salmonids passed through VS fishways. The results of this study play an important role in designing appropriate fishway types for different downstream fish fauna and can be better generalized by complementing quantitative evaluation studies of various fishways as much as possible.

Research on the Hydraulic Characteristics of Island Fishways by Experimental and Numerical Methods

With the development of hydraulic structures, rivers are becoming fragmented, and their connectivity is greatly affected. Important migratory routes through which fish complete their life processes are hindered. In severe cases, it may lead to the extinction of fish species. As facilities commonly used to assist fish upstreaming, fishways are significant for environmental remediation and have received attention from different scholars. This article proposed a new type of fishway, inspired by Tesla valves with obstructing reverse flow characteristics and classic fishway structures. Due to its characteristic of introducing a water-blocking island structure, it was denominated as an island-style fishway. This work studied an island fishway through a combination of physical models and numerical simulations. The results show that this fishway could achieve various flow patterns suitable for fish migration, and the flow rate control was stable. This study also explored the impact of island spacing arrangement on the turbulent structure of the pool chamber. It was found that when the island distance is set at 1.5d, indicators such as flow velocity and turbulent kinetic energy could achieve significant control effects. However, inappropriate d values might cause adverse effects. This research could provide reference ideas for the design of new fishways.

Bidirectional connectivity in fishways: A mitigation for impacts on fish migration of small hydropower facilities

Abstract Most freshwater fish need to move freely through rivers to complete their life cycles. Thus, river barriers (e.g. dams, culverts and gauging stations) may delay, hinder or even block their longitudinal movements, affecting fish conservation. The most widespread solution to allow upstream fish migration are fishways, whereas downstream migration is basically facilitated through spillways, turbines or specific solutions such as bypass systems. So far, studies and scientific discussions concerning bidirectional movements through fishways are scarce and focused on large dams and reservoirs, mainly with large migratory species such as salmonids, rather than smaller facilities and lesser known species. This study investigated bidirectional movements through a small run‐of‐the‐river hydropower plant with a pool‐and‐orifice type fishway, using the Iberian barbel (Luciobarbus bocagei), a potamodromous cyprinid, as the target species. Passive integrated transponder and radio tracking data were collected over 4 years and combined to characterize upstream and downstream movements. The study focused primarily on fish movements through the fishway, but also estimated the multiple associated routes of passage. The results show diverse fish movements with inter‐ and intra‐annual variability, with several individuals performing bidirectional movements and even some fish returning over the years. The documented movements and observations indicate that fishways can serve as an effective bidirectional migration corridor for fish, potentially enhancing the conservation efforts for potamodromous species. This study supports the decision to use fishways as an overall mitigation tool to reduce the impact of small hydropower facilities on fish.

Brown Trout Upstream Passage Performance for a Fishway with Water Drops between Pools beyond Fish Passage Design Recommendations

This work aims to assess brown trout (Salmo trutta) passage through a free-flow pool-weir-type fishway with hydrodynamic notches and extreme water drops between pools. It consists of an old-school fishway design, commonly constructed in salmon rivers of Spain during the period of 1950–1980. To assess their performance, a field test was designed with confined trial conditions during the spawning migratory season. The mean water drop between pools was 0.65 m and the total water height considered for the trial was 11.8 m. The monitoring was carried out using PIT telemetry. The initial hypothesis, considering the fishway design and assessment guidelines, classified this structure as hardly insurmountable. Results showed an ascent success of 19% with a median transit time of 29.1 min/m of ascended height. Larger fish and fishway sections with lower values of volumetric power dissipation were related to a better performance in the passage. The results suggest that in certain circumstances, such as limited construction areas where other design or management options are difficult to implement (e.g., canyons), this type of fishway may be an alternative for the upstream passage of at least a small proportion of the brown trout population, although a selection effect is expected.

Modelling the hydraulic characteristics of diaphragm fishways and the effects on fish habitats

Diaphragm fishways are often used in fishway engineering construction. Although there are an increasing number of new types of fishways, other types of diaphragm fishways can be derived from the combination or evolution of the following three basic types of fishways: vertical slot, overflow weir and orifice. To compare the hydraulic characteristics of different foundation types of fishways, the operations of vertical slot fishways, overflow weir fishways and orifice fishways are calculated by numerical simulation, and we comprehensively compare the flow field characteristics and application scenarios of various types of fishways from the two dimensions of hydraulic characteristics and application characteristics. This paper analyses the hydraulic characteristics of the flow field, such as velocity distribution and turbulent kinetic energy, and analyses the application characteristics of the fishway from the aspects of applicable flow, favourite swimming speed range, explosive swimming speed, fish passing position, and the matching characteristics of typical target fish. It is concluded that the vertical slot fishway can be widely applied to different target fish species due to its own advantages, such as less impact from environmental conditions. The characteristics of the overflow weir fishway and orifice fishway need to be analysed in combination with the hydraulic characteristics of the fishway, the swimming ability of the target fish species and the natural environmental conditions.

Evaluating Attraction and Passage Efficiencies of Pool-Weir Type Fishways Based on Hydraulic Analysis

In this study, a hydraulic analysis technique is presented for evaluating the efficiency of a pool-weir type fishway. The River-2D model with the fish physical habitat module was used for the analysis of the attraction efficiency, and the weighted usable area proposed as an index of the efficiency. For the analysis of passage efficiency, the three-dimensional model, FLOW-3D, was used as an evaluating tool to describe the fluid behavior on a hydraulic structure with a free surface. The ice-harbor type fishway at Dalseong weir in the Nakdong River of Korea was selected as a test-site, and the efficiency was estimated using the hydraulic analysis. The results of River-2D analysis showed that the location of the fishway near the right bank now was not appropriate for attracting the target fish to the fishway due to the deep water depth. The 3D analysis results presented that the flow velocity field inside the fishway showed a similar plunging flow in each pool, but various flow patterns appeared locally.

Experimental Investigation of the Reynolds Shear Stress Exceedance Rate for the Injury and Disorientation Biocriteria Boundary in the Pool-Orifice and Vertical Slot Type Fishways

Fragmentation of rivers has a negative impact on river’s ecological status which can be improved by the construction of fishways next to obstacles in rivers that prevent a free migration. Flow field characteristics are key factors in the design process of hydraulically efficient fishways—flow and turbulence patterns in a functional fishway allow fish to enter, progress through and exit with minimum time/energy expenditure. The aim of this paper is an experimental study of the flow field characteristics measured in the physical fishway model with the goal of providing information on the Reynold’s shear stress distribution that would facilitate their design in accordance with the environmental requirements. The focus of the research was on the nominally hydraulically efficient con-figuration pool-type fishways—pool-orifice and vertical slot. Fishway geometry was varied for bottom slope (7.5%, 10% and 12.5%), pool length (45 cm, 60 cm and 90 cm) and orifice size (8 × 8 cm, 10 × 10 cm and 12 × 12 cm) in a model scaled 1:3 to the prototype. Since Reynold’s shear stress has been identified as the main turbulent parameter affecting fish swimming performance and behavior, it is used as the basis for the analyses. The velocity data were collected with Vectrino ADV and processed in all three planes—streamwise, horizontal and vertical. Reynold’s shear stress data were analyzed according to the injury (>50 N/m2) and disorientation (>30 N/m2) biocriteria boundaries defined in the literature. The percentage of the flow field exceeding the boundaries were analyzed depending on the fishway geometry. The results obtained in this research suggest that the critical design parameter is the orifice size for the pool-orifice fishways and the pool length for the VS fishway. The Reynold’s shear stress is generally the highest in the bottom layer for pool-orifice fishways and the surface layer for vertical slot fishways.

Turning Pools in Stepped Fishways: Biological Assessment via Fish Response and CFD Models

With the aim of building more compact fishways and adapting them to field conditions to improve their location by fish, it is common to use turning pools, reducing the longitudinal development of the construction. However, depending on their design, turning pools may affect the hydraulic performance of the fishway and consequently the fish passage. To study these phenomena, turning pools in a vertical slot and in different configurations of submerged notches with bottom orifice fishway types were assessed. Both types of fishways were studied using numerical 3D models via OpenFOAM, a computational fluid dynamics software, in combination with fish responses, assessed with PIT (Passive Integrated Transponder) tag telemetry for three different species of potamodromous cyprinids in several fishways. Results show differences between the hydrodynamics of straight and turning pools, with lower values in the hydrodynamic variables in turning pools. Regarding fish behavior, the ascent was slower in turning pools but with no effect on passage success and without being a problem for fish migration. This information validates the use of turning pools as a key design component for fishways for studied species.

Updating the consensus on fishway efficiency: A meta‐analysis

AbstractTo update the consensus on the effectiveness of fish passage mitigation structures or “fishways,” I conducted a meta‐analysis on the fish passage literature and synthesized attraction and passage efficiency estimates from 60 peer‐reviewed articles. One hundred unique species were studied at 75 unique fishways of various designs and sizes yielding 210 and 252 estimates of attraction and passage efficiency, respectively. Following Bunt et al. (River Research and Applications, 28, 2012, 457), the fishways were grouped into five types: nature‐like, denil, pool‐and‐weir, vertical slot or locks and lifts that were operated automatically. Generalized linear mixed effects models showed that fishway type was not a significant predictor of passage efficiency, although nature‐like fishways had significantly lower attraction efficiency than other types. Neither fishway slope, nor elevation change was significant predictors of attraction or passage efficiency. Models comparing efficiency between ecological guilds of fishes (pelagic or benthic and rheophilic or limnophilic) showed that attraction and passage efficiency were highest for pelagic rheophiles and lowest for limnophiles. Models comparing migratory guilds of fishes (diadromous, potamodromous, facultative or non‐migratory) showed that diadromous species outperformed other guilds, as expected. Fish that were captured inside or above fishways had significantly higher passage performance than fish that were naive to the fishway. Inconsistency in fishway evaluation methods was pervasive in the surveyed literature and made this meta‐analysis challenging. When designing studies of fishway evaluations, researchers should conform to best practices so that their results are more generalizable and their conclusions of wider scope.

Fish passage assessment in stepped fishways: Passage success and transit time as standardized metrics

Fishways are used worldwide to restore fish migration routes. However, there are few standardized metrics that allow the comparison of their performance in a consistence manner. This paper aims to assess fishway internal passage using two standardized metrics: passage success and transit time. Data from selected 20 field stepped fishways evaluation were gathered from a systematic review and own field experiments, considering potamodromous species as target fish. The influence of main biological and hydraulic parameters on these metrics was analyzed and modeled by logistic regression and survival analysis techniques. Passage success and transit time described reliably fishway performance. Both metrics were significantly influenced by fishway type, volumetric power dissipation, height drop between pools, slope, obstacle height, pool depth, species and fork length in fishway passage. This work may serve as a guide for all engineers and managers working in fishway assessment, design and management to assess and compare other fishways, select proper design parameters and open the discussion and future research on these topics.

Model-based ecological optimization of vertical slot fishways using macroinvertebrates and multispecies fish indicators

Fishway research has long focused on post-establishment assessments to optimize fish passage efficiency. Model-based optimization with the use of hydrodynamic-habitat models (HHMs) has rarely been employed to investigate passage suitability based on key hydraulic variables. In this study, a vertical slot fishway was designed, the hydraulic properties of twelve types that varied by slope, slot width and pool size were simulated using a two-dimensional HHM, and the suitability of macroinvertebrates and of seven fish groups, encompassing various guilds and size classes, was assessed for each fishway type at seven discharge scenarios, ranging from 0.1 m3/s to 1.3 m3/s. Suitability was primarily influenced by water depth. At optimal depths, suitability was fine-tuned by flow velocity to different optima per biotic group based on fixed interplays between discharge, slope and slot width: water depths were higher at high discharges, low slopes and narrow slots; flow velocities were higher at high discharges, high slopes and wide slots. Our ecologically optimal, multispecies, vertical slot fishway, had 5% slope and 30-cm wide slots, with discharges shifting between 0.15 m3/s and 0.6 m3/s to balance the needs of all species and life stages studied. Yet, even this optimal fishway could not guarantee 100% suitability for all species. The overall suitability was moderate (approx. 50–60%), higher at the pools and lower at the slots, and critically influenced by the type of substrate. We conclude that technical fishways cannot be simultaneously ideal for all species and life stages of a river reach/basin, due to the often-contrasting habitat preferences that need to be adapted to fixed interplays of hydraulic conditions. Within these limitations, however, model-based ecological pre-optimization is crucial for optimizing and deploying fishways that will guarantee suitable passage routes for a wide range of species and life stages, ultimately restoring the hydromorphological and ecological connectivity of dammed rivers.

Coarse fishway assessment to prioritize retrofitting efforts: A case study in the Duero River basin

Restoring the longitudinal connectivity of rivers is one of the main objectives of environmental European directives and policies. Fish passes or fishways are one of the most common actions for its restoration. Despite the great number of fish passes constructed during the last two decades to comply with these policies, few of them have been assessed and their suitability for fish movements is unknown. There are different options to assess fish passes, but time and economic costs frequently limit their application. Coarse fishway assessment methods (CFAMs) are an easy, fast and economic alternative for this purpose. This study aims to display the potential of CFAMs to evaluate a large number of fishways, to show the actual status of fishways in an Iberian representative river basin, and to diagnose their suitability and problems. For this, the Spanish Duero River Authority promoted the assessment of 64 stepped fishways in the Duero River basin (Spain) using the AEPS methodology. The results were analyzed considering the four stages that a fish must overcome in a fishway (attraction, entry, passage and exit), the fishway type and the construction period. Among others, results show that 50% of the assessed fishways allow the free movement of fish. However, this percentage could have been greater applying an adequate monitoring program for the fishway design and construction. Furthermore, the diagnosis by stages of the AEPS methodology allowed to identify the attraction and passage as the most problematic stages and also helped to define specific retrofitting solutions for each fishway. The study concludes that the application of CFAM during fishway design, construction and first operation stages can increase their effectiveness and, thus, the number of fish passes that contribute to the restoration of the longitudinal connectivity of rivers.

Fishway Effectiveness and Upstream Residency of Three Fish Species at Four Fishways in Prince Edward Island, Canada

We evaluated passage of Osmerus mordax (Rainbow Smelt), Salvelinus fontinalis (Brook Trout), and Alosa pseudoharengus (Alewife) at 4 fishways on Prince Edward Island, Canada. We implanted fish with passive integrated transponder (PIT) tags and recorded their movements using stationary PIT antennas. Passage at different fishway types was highly variable. Nature-like fishways passed over 96% of Brook Trout and a maximum of 41.8% of Rainbow Smelt. The latter percentage is the highest yet reported in the literature for Rainbow Smelt. Pool-and-weir fishways passed nearly 100% of Brook Trout, 13.2% of Rainbow Smelt, and only 5.6% of Alewife. After passing a fishway, upstream residency was highly variable both among species as well as among individuals within species. Rainbow Smelt were observed spawning within nature-like fishways, suggesting that this type of fishway may also provide spawning habitat. Results highlight the challenge of passing non-salmonid species and indicate nature-like fishways are more appropriate than technical designs for passing Rainbow Smelt.

Passage Performance of Technical Pool-Type Fishways for Potamodromous Cyprinids: Novel Experiences in Semiarid Environments

Endemic freshwater fish from semiarid environments are among the most threated species in the world due to water overexploitation and habitat fragmentation problems. Stepped or pool-type fishways are used worldwide to reestablish longitudinal connectivity and mitigate fish migration problems. Many of them are being installed or planned in rivers of semiarid environments, however, very few studies about fish passage performance through pool-type fishways has been carried out to date on these regions. The present work focuses on the passage performance of two potamodromous cyprinids endemic of these regions, with different ecological and swimming behavior: southern Iberian barbel (Luciobarbus sclateri) and Iberian straight-mouth nase (Pseudochondrostoma polylepis). These are assessed in two of the most common types of stepped fishways: vertical slot and submerged notch with bottom orifice fishways. Experiments were carried out during the spawning season in the Segura River (southeastern Spain), using a passive integrated transponder (PIT) tag and antenna system. Ascent success was greater than 80%, with a median transit time lower than 17 minutes per meter of height in all trials, and for both species and fishway types. Results show that both types of fishways, if correctly designed and constructed, provide interesting alternatives for the restoration of fish migration pathways in these regions.

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.

Development of slope type fishway attached to erosion control dam considering maintaining continuousness of stream

Development of slope type fishway attached to erosion control dam considering maintaining continuousness of stream

Vertical slot versus submerged notch with bottom orifice: Looking for the best technical fishway type for Mediterranean barbels

When engineers and ecologists face a fishway design, many issues need to be considered, the type of fishway being the first and foremost. It is an especially complex issue in areas with species whose migratory and swimming behavior are as yet poorly known as Mediterranean barbels. The present study focuses on the fish passage of two of the most common types of technical fishways: Vertical Slot (VS), and Submerged Notch with Bottom Orifice (SNBO). Both types were studied and compared in terms of ascent ability (as the success rate and transit time) and motivation (as the proportion of attempts and attempt rate), with Iberian barbel (Luciobarbus bocagei) as the target species.Ascent ability in VS and SNBO were similar. More than 90% of fish ascended the fishways successfully and the median transit time to ascend a total water height of 2.25 m was less than 23 min. Fish length had an effect on ascent time, with the biggest ones being faster. Motivation was greater for VS, although not seeming to have a relevant influence in the passage.These results support the use of VS and SNBO in areas with Iberian barbel and provide new data of fishways performance helping ecologists and engineers with their decision making, mainly in Mediterranean areas with similar habitats and species.

A Two-Dimensional Hydrodynamic Numerical Model Applied on Layout of Fishway Entrance and Its Optimizations

The layout of fishway entrance has an important impact on the fish pass activity. In this paper, two kinds of arrangement forms are proposed by analyzing the fish pass objects and the time, the fishway type and the hub dispatching mode for Dayuandu Navigation & Hydropower Complex in Xiangjiang River. Based on the SMS-RMA2 model, a two-dimensional hydrodynamic numerical model with depth-averaged equations is established. The flow conditions at the inlet of different flow rates are calculated and the layouts of fishway entrance are compared and discussed. Meanwhile, the fish pass capacity of different cases is also discussed. The results show that the flow rate at the inlet for case 1 cannot usually meet the optimum flow rate requirment of 0.2m/s ∼ 1.3m/s. However, the better results are found in case 2, the inlet flow velocity of this scheme can meet the requirements of the best fish flow rate under various working conditions, except the practical significance of the entrance cannot be showed. Subsequently, two optimization measures are given in this study to avoid the fish cannot find the entrance of fishway, which also provide some reference for similar projects especially the construction of fishway.