竖缝式鱼道池室结构变化对水力特性的影响分析

竖缝鱼道的消能主要集中在竖缝处,竖缝束窄使水流形成漩涡,导致鱼道内流速过高,水流紊乱。为了改善竖缝式鱼道池室的水流特性,采用雷诺应力(RSM)模型对不同结构形式的同侧竖缝鱼道进行数值模拟。研究表明:在池室内正对竖缝下游布置圆柱型障碍物,竖缝处流速梯度减小,紊动能和雷诺剪切力均降低约20%～30%,这种池型的鱼道水力特性稳定,能满足更多鱼类的过坝。     

An assessment of the effectiveness of a vertical‐slot fishway for non‐salmonid fish at a tidal barrier on a large tropical/subtropical river

Fishways for salmon in temperate rivers have often been successful, but salmonid‐type fishways for non‐salmonid species in tropical and subtropical rivers have frequently failed. This study assessed the effectiveness of modifying a salmonid‐type pool‐and‐weir fishway into a vertical‐slot design on a tidal barrage on the subtropical Fitzroy River, in Queensland, north‐eastern Australia. In 38 paired samples of the top and bottom of the fishway, over 16 months, 29 fish species and over 23 000 fish were collected at a maximum rate of 3400 per day. This study shows much greater potential for success with a vertical‐slot fishway as relatively few fish negotiated the original pool‐and‐weir design. Common species using the vertical‐slot fishway included blue‐catfish (Arius graeffei [Ariidae]), bony herring (Nematalosa erebi [Clupeidae]), striped mullet (Mugil cephalus [Mugilidae]), barramundi (Lates calcarifer [Centropomidae]), and long‐finned eels (Anguilla reinhardtii [Anguillidae]). Freshwater shrimp (Macrobrachium australiense [Palaemonidae]), juvenile crabs (Varuna litterata [Grapsidae]) and long‐finned elvers did not ascend the full length of the fishway and specific fishways for these species are recommended. Fish between 25 and 640 mm in length ascended the fishway, although the passage of smaller size classes of immature fish was restricted and this may be important for the sustainability of these migratory populations. The barramundi (200–640 mm) which ascended the fishway were all immature fish. However, during a period of low river flows enlarging the width of the vertical‐slot from 0.15 to 0.45 m only encouraged a small number of larger fish (890 mm maximum length) to enter. The strong diel movement patterns of many species will need to be considered in future fishway design. Blue‐catfish could ascend the fishway in 2 h, but many fish remained in the fishway and this behaviour may cause crowding and a reduction in fishway capacity. Further work is needed to assess the proportion of fish finding the fishway entrance. However, the findings suggest that vertical‐slot fishways with lower water velocities and turbulence than salmonid fishways have great potential to pass the diverse migratory fish fauna of subtropical and tropical rivers. Copyright © 1999 John Wiley & Sons, Ltd.     

隔板型式对竖缝式鱼道水力特性的影响研究

通过改变隔板中竖缝的位置和数量,构造四种不同型式的竖缝式鱼道,利用计算流体动力学分析工具,获得了不同工况下四种鱼道模型的三维流场。研究表明:同一鱼道型式、同一底坡,其主流曲线形式(池室内水流形态)与流量变化无关。研究结果可为鱼道设计提供参考。     

Movement of three non‐salmonid fish species through a low‐gradient vertical‐slot fishway

Well‐designed fishways have assisted in restoring migrations and rehabilitating riverine fish species in all continents. The performance of fishways varies greatly with their type, design and operating regime, and with the species involved. Vertical‐slot fishways are widely used to overcome low‐level barriers, especially for non‐salmonids. Important issues remain in the design of fishways to meet performance and cost criteria, including the relationship between fishway bed gradient and the fish that ascend, and whether resting pools are needed. Models of species' movement patterns can inform fishway designers about likely fish response to various design options, and can lead to improved efficiency and effectiveness. Models of general movement patterns of three potamodromous non‐salmonid fishes in the Murray River, Australia, were developed from empirical data in a low‐gradient vertical‐slot fishway. The models integrate data on times of entry and exit, ascent rates, and whether fish continued to ascend during the night. These fish species did not favour resting pools. Ascent rates of fish ≥120 mm were more closely related to fish behaviour than to length; for a given fishway height, reducing bed slope by increasing the number of pools may slow the ascent of such fish, whereas enlarging pool volumes increases costs. Copyright © 2010 John Wiley & Sons, Ltd.     

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

Globally, 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.     

异齿裂腹鱼通过鱼道内流速障碍能力及行为

鱼类通过流速障碍能力是鱼道设计的主要生态指标,目前国内外主要使用封闭游泳水槽进行鱼类各种游泳速度指标及游泳行为研究,其水流流态及鱼类游泳行为与鱼类通过鱼道的实际状态有较大的差距,有必要结合鱼类游泳速度指标来探索能够更加准确量化鱼类通过鱼道流场的游泳能力测试方法。首先,在封闭游泳水槽中通过速度递增法测得异齿裂腹鱼临界游泳速度(101.01±20.86 cm/s)和突进游泳速度(196.94±21.80 cm/s);然后,以临界游泳速度和藏木水电站鱼道竖缝流速(110.00 cm/s)为参考,通过在开放游泳水槽内加不同束窄梯形体,形成类竖缝式鱼道的鱼类自主游泳能力测试水槽,开展两种底坡条件下4级短竖缝(工况1和工况2竖缝流速为101.55±14.87 cm/s、114.63±24.28 cm/s,竖缝顺水流长度均为40 cm)和单级长竖缝(工况3竖缝流速为137.45±17.63 cm/s、竖缝顺水流长度为160 cm)下试验鱼通过流速障碍能力和行为研究。试验结果表明:工况1、工况2下试验鱼通过4级竖缝成功率分别为82.05%、84.62%,通过流速大于临界游泳速度的竖缝时,持续爆发游泳时间为0.52±0.34 s;工况3下93.33%试验鱼以209.43±21.76 cm/s游泳速度成功通过单级长竖缝;3种工况下试验鱼通过流速大于临界游泳速度的竖缝时,以与突进游泳速度无显著性差异(P0.05)的恒定游泳速度(214.01±30.64 cm/s)上溯。鱼类游泳轨迹与流场耦合分析表明:鱼类上溯所需时间及路径长度与其选择的游泳路径密切相关,试验鱼通过借助回流区同向水流推动,增加上溯效率。本文研究方法及研究结论可为鱼道设计、改造、评价提供依据。     

辽河盘山闸鱼道设计研究

盘山闸作为辽河最下游的水利枢纽,阻隔了河口水生物的洄游通道,改变了水生态环境,破坏了河口地区水生生物的生态平衡。为了缓解水利工程对水生态环境带来的不利影响,拟在闸址处增设鱼道。对盘山闸鱼道的过鱼对象、鱼道型式与布置以及垂直竖缝式鱼道主要设计参数进行了分析讨论,最终选择布置紧凑、占地范围小、诱鱼效果好、施工容易、运行管理方便、工程投资省的“S”型鱼道。所选鱼道正在施工建设中,可为类似鱼道设计运行借鉴参考。     

鱼道水力特性研究进展

综述竖缝式、池堰式和涵洞式、丹尼尔式及组合式鱼道水力特性的国内外研究进展;对比分析水流流态、流速场特征、流量与水深的关系、紊流特性及消能率等几方面对不同鱼道的水力特性的影响;得出了竖缝式鱼道中无量纲流量与相对水深之间呈线性关系的结论,列出了池堰式鱼道中流量与水深的关系式;指出鱼道中紊流的紊动能、紊流强度及紊流结构均会对鱼道水力特性、鱼类对栖息地的选择以及鱼类通行造成较大影响;展望鱼道未来研究重心会逐渐集中于鱼道内紊流特性及其数值模拟的研究,尤其是紊流结构的研究。此外,不同结构形式鱼道内水力条件对鱼类通行的影响及改善措施亦将成为未来研究热点之一。     

USING AN EXPERIMENTAL IN SITU FISHWAY TO PROVIDE KEY DESIGN CRITERIA FOR LATERAL FISH PASSAGE IN TROPICAL RIVERS: A CASE STUDY FROM THE MEKONG RIVER,CENTRAL LAO PDR

Fish passage through an experimental vertical‐slot fishway was assessed at a floodplain regulator on the Mekong River in Central Laos between April and July 2009. Experiments were conducted to investigate the influence of fishway floor slope (1v:15h or 1v:7.5h) on fish passage success with a view to developing a series of optimal design criteria for the construction of vertical‐slot fishways at other barriers to fish passage in the Lower Mekong Basin. A total of 14 661 fish from 73 species were captured during the experiments. Catches were dominated by riverine (white) (n = 51; 69% of total) and floodplain (black) species (n = 15; 20%) which represented 19 families in total. The work demonstrated that fish were actively attempting upstream passage from the Mekong River to an adjacent floodplain and displayed strong migratory behaviour during river level rises. Migratory activity was greatest during sharp rises in water level but reduced substantially when river level fell. Fish community composition varied greatly among the two fishway floor slopes and the control group. More fish species were collected from control samples, but the most fish and species were collected when the fishway was configured on a moderate hydraulic slope (1v:15h). A range of size classes were also collected from control and moderate‐slope groups, but steeper‐gradient catches were dominated by larger fish. This study demonstrated that vertical‐slot fishways could provide passage for a biodiverse fish community where fish move laterally onto floodplains. The construction of fishways which consider the local fish ecology and hydrology may therefore represent a valuable management tool to help restore important movement pathways for tropical freshwater fish. Copyright © 2011 John Wiley & Sons, Ltd.     

MULTISPECIES FISH PASSAGE BEHAVIOUR IN A VERTICAL SLOT FISHWAY ON THE RICHELIEU RIVER,QUEBEC, CANADA

A shift from target species to ecosystem restoration has generated interest in developing fishways that are capable of passing entire fish communities. Although a number of multispecies fishways now exist in North America, evaluations of these fishways are lacking. We used a passive integrated transponder antenna array to quantify passage success and passage duration of fish using a vertical slot fishway (85 m in length, 2.65 m elevation rise, 12 regular pools and 2 turning basins) at a low head dam on the Richelieu River in Quebec, Canada. Fourteen of the 18 tagged species re‐ascended the fishway, and passage efficiency was highly variable among species (range 25%–100%); however, it was >50% for five of the species well represented in this study (n > 10) (Atlantic salmon, channel catfish, smallmouth bass, walleye and white sucker). Passage duration was likewise highly variable both among and within species (e.g. 1.0–452.9 h for smallmouth bass, 2.4–237.5 h for shorthead redhorse). Although this fishway design was not uniformly successful in passing fish of all species, this study does reveal the species that have problems with ascent and provides an estimate on the time spent in the fishway that is an important component of passage delay. Such information could be used to inform future design refinements to facilitate passage of the entire assemblage with minimal delay. Copyright © 2012 John Wiley & Sons, Ltd.     

The use of behavioural metrics to evaluate fishway efficiency

Fishways 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.     

Effects of water velocity and turbulence on the behaviour of Iberian barbel (Luciobarbus bocagei,Steindachner 1864) in an experimental pool‐type fishway

The restoration of fish passage has been focused on anadromous fish species, whilst studies accommodating passage of coarse species have often been considered incidental, yet frequently these are the predominant group of species encountered in rivers. In addition, fishway designs depend greatly on the interplay between hydraulics and biomechanics, yet very little data are available on the responses to specific hydraulic settings for these species. This study aims to explore the effects of water velocity and turbulence on the behaviour of a cyprinid species ‐ the Iberian barbel Luciobarbus bocagei (Steindachner, 1864) ‐ particularly their upstream movements upon different discharges (38.5 to 77.0 L · s^?1), through an indoor full scale pool‐type fishway prototype. Larger adults had a higher passage success (mean = 79%) and took less time (mean ± SD (min): 5.7 ± 1.3) to negotiate the entire six pool fishway, when compared to small adults. Correlation analysis between hydraulic variables and fish transit time yielded different results. Correlations were found to be the highest between the horizontal component of Reynolds shear stress and fish transit time, particularly for smaller size‐individuals (r = ?0.45; p < 0.001), highlighting this variable as a key‐parameter which strongly determines the movements of Iberian barbel. The present study identified key factors on Iberian barbel movements that may have direct application to future fishway designs for this species and for other ‘weak’ swimmers. Copyright © 2010 John Wiley & Sons, Ltd.     

Not just a migration problem: Metapopulations,habitat shifts,and gene flow are also important for fishway science and management

Worldwide, fishways are increasingly criticized for failing to meet conservation goals. We argue that this is largely due to the dominance of diadromous species of the Northern Hemisphere (e.g., Salmonidae) in the research that underpins the concepts and methods of fishway science and management. With highly diverse life histories, swimming abilities and spatial ecologies, most freshwater fish species do not conform to the stereotype imposed by this framework. This is leading to a global proliferation of fishways that are often unsuitable for native species. The vast majority of fish populations do not undertake extensive migrations between clearly separated critical habitats, yet the movement of individuals and the genetic information they carry is critically important for population viability. We briefly review some of the latest advances in spatial ecological modelling for dendritic networks to better define what it means to achieve effective fish passage at a barrier. Through a combination of critical habitat assessment and the modelling of metapopulations, climate change‐driven habitat shifts, and adaptive gene flow, we recommend a conceptual and methodological framework for fishway target‐setting and monitoring suitable for a wide range of species. In the process, we raise a number of issues that should contribute to the ongoing debate about fish passage research and the design and monitoring of fishways.     

Preferential behavior of Tribolodon hakonensis for fishways according to biological characteristics

In 2012, the fishway in the Miyanaka Intake Dam in Niigata Prefecture, Japan, was reconstructed and divided into three fishways (ice-harbor-, stair-, and rock-ramp-type) with different flow velocities and water depths. We conducted an adaptive monitoring survey in these fishways from 2012 to 2020, and 33 fish types were found, including migratory, swimming, small swimming, and benthic fishes. Many species displayed a preference for specific fishways. The run-up for Tribolodon hakonensis was studied to determine the effects of physical parameters such as body length, rush speed for instantaneous swimming, water temperature, and presence/absence of nuptial coloration on fishway preference. T. hakonensis with nuptial coloration had greater body length and higher rush speeds than those without it. They also preferred the ice-harbor fishway, whereas their shorter, uncolored counterparts preferred the stair and rock-ramp alternatives. The environmental conditions selected by T. hakonensis changed according to their growth stage, as did fishway preference. Changes in fishway environmental conditions may have influenced the observed differences in fishway populations. It was thus confirmed that developing fishways with different flow velocities and water depths is effective in supporting the various life stages of T. hakonensis.     

Hydropower Development,Riverine Connectivity,and Non‐sport Fish Species: criteria for Hydraulic Design of Fishways

Hydropower barriers are among the most conspicuous anthropogenic alterations to natural riverine connectivity, resulting in species‐specific effects linked to dispersal abilities, especially swimming performance. They may present a particular problem for small‐bodied ‘non‐sport fish’, such as those that characterize the freshwater communities of temperate regions in the Southern Hemisphere. Recent studies have suggested that nature‐like fishways could ensure passage of diverse fish assemblages through hydropower barriers. Through experiments performed in a swim tunnel, we present, for the first time, fishway design criteria for two non‐sport species endemic to Chile, a country experiencing rapid hydropower development. In`cremental velocity tests showed that Cheirodon galusdae and juveniles of Basilichthys microlepidotus were capable of very similar standardized critical swimming speeds of 69.7 and 69.6 cm s^?1, respectively. When expressed in units of body lengths, C. galusdae was capable of very high critical speeds of 16.2 bl s^?1, whereas for B. microlepidotus, this was 7.6 bl s^?1. However, fixed velocity tests revealed that the swimming endurance of the latter species was slightly higher. Dimensionless analysis showed a clear relationship between fatigue time and fish Froude number, similar to that already described for subcarangiforms. Based on these results, we present fishway design curves indicating a transition from sustained to prolonged swimming at a fishway length of 15 m. Our results show that the swimming capacity of these species is well‐suited to the mean flow velocity field described for nature‐like fishways. However, more work is required to understand the effects of turbulence on the passage of non‐sport species. Copyright © 2016 John Wiley & Sons, Ltd.     

Body size,experience, and sex do matter: Multiyear study shows improved passage rates for alewife (Alosa pseudoharengus) through small‐scale Denil and pool‐and‐weir fishways

Alewife (Alosa pseudoharengus) passage through 3 fishways was assessed during the 2013–2016 spawning runs in 3 rivers of the Isthmus of Chignecto, Canada. From April 24 to June 10, 5,423 alewife with a mean ± SD fork length of 227 ± 18 mm were tagged with passive integrated transponders. During their tagging year, approximately half of individuals (40% to 64%) went undetected whereas those detected used fishways from April 16 to July 8. Detected alewife were significantly longer than those undetected. Attraction rates to fishway entrances in 2015 and 2016 ranged from 85% to 98%. Annual fishway passage rates for pooled fish tagged that year and returnees, varied from 64% to 97% for 2 Denil style fishways. A pool‐and‐weir fishway that was dysfunctional (2013), repaired (2014), and replaced (2015–2016) yielded 0.5%, 25%, 60%, and 73% annual pooled passage rates, respectively. Larger individuals, previously tagged returnees, and males compared to females of a similar size had higher passage success suggesting some fishways may apply population‐level selective pressures. Alewife passage rates related to fishway style, design, and proper function, with greater passage for the 2 Denils than the pool‐and‐weir fishway in our study. Regular structural maintenance and fish passage reviews are essential management considerations to ensure fishway functioning and river connectivity. Replacement of a fishway with poor fish passage may be the best option to improve passage rates. Future research should address the effects of multiple anthropogenic instream obstructions, environmental variables, negative sublethal post‐tagging effects, and the importance of returnees on fish passage rates in fishways.     

Evaluation of nature‐like fishways for re‐establishing connectivity in fragmented salmonid populations in the River Emån

We evaluated the function of two nature‐like fishways for re‐establishing connectivity for anadromous salmonids in the regulated River Emån. Between 90 and 100% of the salmonids that entered the fishways actually passed through them, with median speeds of 180–190 m h^?1. Only 50% of the anadromous brown trout that passed the first fishway also passed the second one, indicating that the fish might have had problems locating the upstream fishway. The fishways were also observed to function as a passage for downstream post‐spawning migrants. The densities of brown trout yearlings upstream of the fishways were higher in 2002, after the fishways were built, than during pre‐fishway years. In control sites in other parts of the river as well as in a nearby river, no changes in yearling densities were observed. Thus, the fishways are working for upstream spawners, albeit at a recolonization rate that is slower than expected. Copyright © 2005 John Wiley & Sons, Ltd.     

齐口裂腹鱼幼鱼在竖缝式鱼道模型中的上溯行为研究

为了解齐口裂腹鱼在鱼道中的上溯情况,在大比尺竖缝式鱼道物理模型中开展了以齐口裂腹鱼幼鱼为过鱼对象的过鱼试验研究。试验中对通过时间、通过率和上溯轨迹进行了记录,并运用Spearman秩相关分析对齐口裂腹鱼的上溯轨迹和池室结构的水力因子(流速、紊动能、总水力应变)进行了分析。研究发现,试验用鱼通过时间平均值为132.7s,多数鱼倾向于快速通过鱼道完成上溯。试验鱼道通过率为71.9%,过鱼效果良好。多数齐口裂腹鱼上溯过程中会避开高流速区、高紊动能区和高水力应变区,在池室内齐口裂腹鱼上溯轨迹主要分布于上述参数较低的右侧回流区和隔板背水面,竖缝断面处多数齐口裂腹鱼选择上述参数相对较低的隔板侧区域通过。研究结果可为相关竖缝式鱼道设计和实践提供参考。     

Physical modelling of pool and weir fishways with rock weirs

The flow characteristics of pool and weir fishways with rock weirs were studied through physical modelling. Detailed flow measurements were obtained using an acoustic Doppler velocimeter to understand how weir geometry, discharge, and bed slope affect flow patterns, velocity, turbulence kinetic energy, turbulence intensity, and Reynolds shear stresses in the fishway. The weir geometries used in this study are similar to those typically used for river restoration projects. The use of a V‐shaped rock weir was found to reduce the mean streamwise velocity in the pools by about 20% but more than double the maximum velocity magnitude. Two stage–discharge relationships were developed using the standard weir equation and a modified discharge coefficient to account for both flow over the weir and orifice flow through the base of the weir. The use of V‐shaped rock weirs has the potential to offer significant advantages in assisting multispecies fish migration. The results of this study can be applied to the hydrotechnical design of pool and weir fishways with rock weirs and for river restoration projects.