以洋塘水闸鱼道为例浅议我国鱼道的有关问题

鱼道在我国发展历程较短,主要集中于20世纪50年代末至80年代初。其中洋塘水闸鱼道在模型试验、鱼道建设、运行观测及过鱼效果等方面均具有典型性,在我国已建成的鱼道中较具代表性。根据洋塘鱼道的建设运行情况,分析了我国鱼道存在的问题,并提出了相关的建议。     

我国鱼道的建设现状与展望

总结分析了国内外鱼道建设特别是我国2000年以来的鱼道修建、鱼道设计研究(鱼道类型、鱼道位置与水力设计参数三方面)概况,分析显示近年来我国鱼道修建以垂直竖缝式和仿自然鱼道为主,且对应的坝高范围也比较广,鱼道深度基本为2.5～3.0m,流速为0.6～1.2m;剖析了我国鱼道建设存在的主要问题是缺乏正确的鱼道发展认识,鱼道技术与管理制度方面也存在不足;提出了鱼道适应性管理理念,通过监测管理发现问题重新调整鱼道设计、运行及管理方案,以期发挥鱼道的最大效益;展望鱼道发展需要制度保证,完善技术规范,重视基础研究且加强学科间合作,切实落实鱼道适应性管理。     

多布水电站鱼道工程设计符合性检验及改进措施研究

鱼道作为主要过鱼设施类型被应用于缓解大坝对鱼类洄游的阻隔影响，近年来国内建成的鱼道工程大多采用竖缝式鱼道。由于施工工艺和方法等因素，竖缝式鱼道施工常出现设计符合性偏差问题，影响鱼道工程预期过鱼效果，进行设计符合性检验，分析工程施工与设计不相符导致的功能损失。通过以多布水电站鱼道工程为例，开展鱼道工程设计符合性检验，针对鱼道工程存在问题提出改进措施并分析效果，提升了多布水电站鱼道运行效果和管理能力，可为国内同类鱼道建设提供参考。     

鱼道应用现状和研究进展

 通过国内外鱼道研究、应用资料以及现场调研,比较详细地介绍了国内外鱼道设施的建设、发展过程和鱼道结构所包含的主要类型;列出了国内外多个鱼道隔板型式和相应的水力特性;总结了鱼道设计的一般性原则;分析了国内外鱼道过鱼条件和适用情况的差异以及我国鱼道设计中存在的问题等。最后提出在现阶段及今后,我国水利水电工作者需要的鱼道设计资料以及开展鱼道研究的主要内容。     

吉林省老龙口水利枢纽工程鱼道设计

老龙口水利枢纽鱼道是我国第一座通过大马哈鱼的鱼道,也是我国水头差最大的鱼道和底坡最陡的鱼道,该鱼道的建设可以进一步研究建筑物的结构尺寸、型式、水力特性及运行过程,并为以后同类型鱼道的设计、施工、运行提供有益的经验。     

仿自然型鱼道进出口布置试验研究

仿自然型鱼道能有效减轻水利工程建设对鱼类的影响,而鱼道进出口附近的水流条件如何,直接关系到仿自然型鱼道能否应用成功。在分析和总结国内外仿自然型鱼道建设及研究现状的基础上,结合某工程仿自然型鱼道水力学整体模型试验,重点研究了电站不同运行方式下的鱼道进、出口流态,流速分布等水力参数,并进行了活鱼试验,对该工程仿自然型鱼道进、出口的布置提供了推荐方案,为较大水头仿自然型鱼道进、出口的布置研究提供参考。     

浅谈水电工程鱼道运行管理

近年来我国大中型水电工程已建或拟建近20座上行鱼道工程,由于国内鱼道工程技术尚不够成熟,且普遍存在着重前期设计,轻后期运行管理的问题,新建鱼道很少达到预期过鱼效果。通过调研典型上行鱼道运行现状,梳理了鱼道运行管理方面存在的问题,并借鉴美国相关机构的鱼道运行管理模式,提炼出鱼道运行管理工作要点,构建了鱼道运行管理体系,为水电行业鱼道规范化运行管理提供参考。     

沙坪二级水电站鱼道设计研究

鱼道是减缓水利工程建设对鱼类阻隔效应的重要措施。根据沙坪二级水电站的工程特点,结合水电站影响范围内鱼类资源情况,进行了鱼道布置方案比选和设计,最终选择过鱼效果好、运行维护较简单的左岸鱼道布置方案,鱼道结构采用竖缝式。利用水工模型试验对鱼道内部结构、鱼道枢纽布置、弯道布置形式等进行分析,验证了此鱼道设计方案的合理性和可行性。沙坪二级水电站鱼道的修建,在一定程度上减缓了水电站阻隔对水生生态环境的影响,为鱼道设计积累了宝贵的经验,可为类似工程提供一定的借鉴。     

大藤峡水利枢纽工程南木江生态鱼道规划浅析

为解决水利工程建设后阻隔鱼类洄游、阻断保护区与坝下两个鱼类种群的基因交流及种群间遗传交流受阻的问题,笔者以大藤峡水利枢纽工程南木江副坝为例,结合南木江副坝的布置、地形条件和过鱼特性研究了过鱼设施方案,确定采用“仿生态鱼道+工程鱼道”相结合的生态鱼道,详细介绍生态鱼道布置、鱼道流速、工程鱼道体型、仿生态鱼道体型和鱼道辅助设施等规划设计情况。该鱼道设计符合水库运行特性,满足鱼类洄游和过鱼要求,同时满足生态流量下泄要求,可为类似过鱼设施的研究提供一定的借鉴。     

水利水电开发中鱼道的研究现状与发展趋势

鱼道的研究在我国水利水电开发中已有将近30多年的空当,已有的鱼道基本上都不能成功运行,与国外的鱼道发展明显拉开了很大差距。在生态平衡话题日益热烈的同时,我国的鱼类种群正在逐步缩小,部分珍惜鱼种甚至濒临灭绝,人工繁殖并不能发展物种种类的多样化。本文就这一视角,阐述了鱼道在水利水电开发中的重要性、作用、发展历程及其研究现状,详细介绍了现有的鱼道类型、型式以及目前运行较成功的案例。基于科技进步与生态保护的双重角度,我国应对目前国内鱼道存在的问题引起高度重视,吸取更多国外的成功经验,为我国未来水利水电开发中的鱼道发展和生态保护奠定基础。     

蒙古国都日根水电站鱼道建设的启示

通过对国内外鱼道发展现状和趋势的分析,对几种常用鱼道的优缺点做了比较,结合都日根水电站所在秦诺哈拉依赫河鱼类生长繁殖特点,采用了垂直竖缝式加小底孔相结合形式的鱼道设计。实践证明此鱼道设计有效保护了鱼类及河流生态的预期作用,具有一定的科学性、实用性和可推广性,对我国中小河道枢纽建设具有一定的参考价值。     

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.     

蒙古国都日根水电站鱼道建设的启示

通过对国内外鱼道发展现状和趋势的分析,对几种常用鱼道的优缺点做了比较,结合都日根水电站所在秦诺哈拉依赫河鱼类生长繁殖特点,采用了垂直竖缝式加小底孔相结合形式的鱼道设计。实践证明此鱼道设计有效保护了鱼类及河流生态的预期作用,具有一定的科学性、实用性和可推广性,对我国中小河道枢纽建设具有一定的参考价值。     

Effects of bed slope on the flow field of vertical slot fishways

Vertical slot fishways (VSFs) are the most efficient and least selective typology of technical fish passage, due to their ability to remain effective even when significant upstream and/or downstream water level fluctuations occur. Fishway construction costs can be reduced by increasing its bed slope, but this affects the flow field inside the pools, with higher head drops between the basins, as well as turbulence levels and flow velocities, which may affect fish passage. In light of this, a VSF was investigated by 3D numerical simulations to identify the possible effects of the bed slope (using values from 1.67% to 10%) on the flow field and subsequent implications for fish passage. A particular focus was devoted to cyprinind species, but the results can be extended to other species of similar swimming abilities and, therefore, be applicable to multispecies rivers. Flow velocity and turbulence values such as turbulent kinetic energy and Reynolds stresses were analysed from a fish passage perspective in relation to threshold values derived from previous studies. Pool areas where turbulence values are compatible with fish ability and behaviour were quantified. Maps of the location of fish‐friendly zones in the VSF pools were produced and can constitute a reference for practical applications in fishway design. The flow field generated with bed slopes lower than 6.67% is more compatible with fish swimming capabilities, because it exhibits a predominantly 2D behaviour and more suitable hydraulic conditions, whereas at higher slopes, turbulence levels in the pools increase.     

Design of a bilateral-symmetric multi-slot fishway and its comparison with vertical slot fishway in terms of hydraulic properties

Aiming at improving the hydraulic properties and enhancing the fish passage efficiency, this study proposes a novel bilateral-symmetric multi-slot fishway (BMSF) by combining the structural features of a double-sided vertical-slot fishway, multi-slot fishway and T-shape fishway. Eight BMSF cases are further designed by adjusting the slot width and the distance between the short baffle and the front end of the central wall, in order to achieve the relatively best hydrodynamic characteristics. The flow fields of two vertical-slot fishways and eight BMSF fishways are obtained by numerically solving the Reynolds-averaged Navier–Stokes equation, the volume-of-fluid equation and the k-ω-SST turbulence model. Numerical results manifest that the recommended BMSF-8 provides the smallest values in terms of the maximum time-averaged velocity magnitude (1.42 m s⁻¹), the maximum time-averaged turbulent kinetic energy (0.132 m² s⁻²), the maximum time-averaged Reynolds shear stress component (44 Pa), the spatial-mean time-averaged velocity magnitude (0.58 m s⁻¹), and the spatial-mean time-averaged turbulent kinetic energy (0.042 m² s⁻²) in the middle pool at Q = 1000 L/s. Even for the depth-mean time-averaged velocity magnitude at the slot and the volume percentages of some critical physical quantities, BMSF-8 is also superior to the other cases. To sum up, BMSF-8 leads to the relatively lowest flow velocity and turbulence, being more suitable for the passage of the whole fish community (especially for small-sized fishes with weaker swimming ability). In addition, the generalizability of the aforementioned superiority of BMSF-8 is displayed by providing the numerical results of four operating conditions (i.e., Q = 600, 800, 1000 and 1200 L/s).     

Turbulent flow field comparison and related suitability for fish passage of a standard and a simplified low‐gradient vertical slot fishway

Fishways are hydraulic structures that allow passage of fish across obstructions in rivers. Vertical slot fishways—VSFs—are considered the most efficient and least selective type of technical fishway solutions, especially due to their ability to remain effective even when significant upstream and/or downstream water level fluctuations occur. The scope of the present study is to perform numerical simulations in order to investigate and compare the hydraulic turbulent flow field in a standard and a simplified version of the most common VSF design. Implications in relation to fish swimming behaviour and fish passage performance are discussed. Different water depths (as well as discharges) were investigated, using a bed slope of 5%, as a reference for low‐gradient VSFs with a very limited selectivity that can be used in multispecies rivers in grayling‐barbel regions. Results show that maximum values of velocity, turbulent kinetic energy, and Reynolds stresses are higher in the standard design. However, corresponding to slot geometry and orientation, the direction of the main jet in the simplified design is more inclined towards the left side of the pool. This causes the eddy to split into 2 smaller ones; the minimum eddy dimension is reduced from 0.4–0.5 to 0.2–0.3 m. These dimensions are detrimental for fish passage efficiency, being more comparable with fish length (0.15–0.40 m), thus affecting migrating fish stability and orientation. Furthermore, the standard design provides a more straightforward upstream path and wider areas of low flow velocities and turbulence, useful for fish resting. Therefore, it is recommended that the standard design should be preferred over its simplified version, even if its construction costs are around 10–15% higher than the simplified one.     

Survey on performance of vertical slot and nature-like fishways at Angu hydropower station,Southwest China

To restore dam-blocked natural fish migratory passages, a growing number of artificial fishways have been built in water conservancy and hydropower projects in China. The Angu hydropower station involved diverse important fish habitats in the lower reaches of the Daduhe River in Southwest China. Therefore, a vertical slot fishway (VSF) and a nature-like fishway (NLF) were built near the backwater area of the reservoir to connect the upstream and downstream habitats. Hydrodynamic and aquatic ecological surveys were conducted after the completion of the project to estimate the fish passing effect of the two fishways. The results indicated that both fishways were in effective operation and could maintain the desired hydrodynamic conditions and be used by several local fish species. During the survey, 149 fish from 15 species and 111 fish from 17 species were captured by the traps in the VSF and NLF, respectively, while 1 263 fish from 27 species were found in the downstream area. Some species captured in the VSF were not found in the NLF, and vice versa, which implied the different preferences of fish. Meanwhile, 3 789 signals including 2 099 upward ones and 1 690 downward ones were monitored with an ultrasonic fish detector at the inlet of the VSF. These findings revealed the characteristics of fish species observed in and near the fishways and provided valuable insights into the different fish passing capabilities of VSF and NLF.

     

同侧导竖式鱼道水力特性试验研究

以某水电站鱼道体型为研究基础,通过1∶10鱼道局部模型,对同侧竖缝式池室的水力特性进行了试验研究,得到了过鱼池室流态、流速分布以及适合目标鱼类上溯的路径等,并对隔板体型、竖缝宽度以及池室长度等进行了分析论证。试验结果表明,该隔板型式、池室尺寸以及池底坡度的同侧导竖式鱼道参数设计基本合理,比较适合需要保护的4大家鱼洄游上溯。通过活鱼试验,验证了鱼类上溯喜好的水力条件等。