Abstract Globally, gauging weirs are commonly installed in rivers to monitor flows. They have widespread negative impacts on the upstream movement of fish due to the barriers created by the unfavourable hydraulic conditions on the downstream face. There is a need to develop simple low-cost solutions to enhance multi-species fish passage, while not impacting the ability of these structures to gauge flow or increasing their potential to accumulate debris. This study investigated the use of an array of Cylindrical Bristle Clusters (CBCs), mounted on the downstream face of Crump weirs, to improve upstream passage of multiple species of fish while maintaining gauging accuracy. The simplicity and modularity of the design helps improve cost effectiveness and ease of installation. Laboratory tests with roach (Rutilus rutilus) showed that the passage efficiency of a Crump weir was increased from 0% (control) to ≈30% when retrofitted with CBCs. Swim path analysis indicated fish utilised low velocity zones in the wake of clusters to facilitate passage. Time taken to pass the weir and length of the swim path were greatest under the highest cluster density, where manoeuvrability was most constrained. Following these promising experimental results, the fish pass efficiency of a weir retrofitted with a staggered array of CBCs, was evaluated in the field. Upstream passage of a number of non-salmonid fish, including chub (Squalius cephalus) and roach, was monitored using Passive Integrated Transponder telemetry at a 7 m long, 1.2 m wide, Crump weir with a 1:5 downstream slope. Overall passage efficiency, considering all species, increased from 2% to 14% when the fish pass was installed, and for chub from 0 to 52%. Debris accumulation was minimal during the test period. Assessment of the impact of a variety of CBC array densities on gauging was also undertaken. As predicted using theory, there was no effect on gauging when arrays were placed downstream of the point at which flow regime changes from sub- to supercritical. This study highlights the potential for a staggered array of CBCs to improve the upstream passage of multiple species of fish at gauging weirs, common barriers to fish migration throughout the world, without affecting the accuracy of flow gauging.

中文翻译：

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使用圆柱形鬃毛簇作为一种新型的多物种鱼通道，以促进测量堰的上游移动

摘要 在全球范围内，通常在河流中安装测量堰来监测流量。由于下游工作面不利的水力条件造成障碍，它们对鱼类的上游运动产生广泛的负面影响。需要开发简单的低成本解决方案，以增强多物种鱼类的通行能力，同时不影响这些结构测量流量的能力或增加其堆积碎片的潜力。本研究调查了使用安装在 Crump 堰下游面的一系列圆柱形鬃毛簇 (CBC) 来改善多种鱼类的上游通道，同时保持测量精度。设计的简单性和模块化有助于提高成本效益和易于安装。用蟑螂 (Rutilus rut​​ilus) 进行的实验室测试表明，当加装 CBC 时，Crump 堰的通过效率从 0%（对照）增加到 ≈30%。游泳路径分析表明，鱼群会利用低速区来促进通过。在最高集群密度下，通过堰所需的时间和游泳路径的长度最长，此时机动性最受限制。根据这些有希望的实验结果，在现场评估了用交错排列的 CBC 改装的堰的鱼通道效率。使用被动集成转发器遥测技术在 7 m 长、1.2 m 宽、下游坡度为 1:5 的 Crump 堰上监测了许多非鲑鱼（包括鲢鱼（Squalius cephalus）和蟑螂）的上游通道。总通过效率，考虑到所有物种，安装鱼道时从 2% 增加到 14%，而对于鲢鱼从 0 增加到 52%。在测试期间碎片堆积最少。还评估了各种 CBC 阵列密度对测量的影响。正如使用理论预测的那样，当阵列放置在流态从亚临界变为超临界的点的下游时，对测量没有影响。这项研究强调了交错排列的 CBC 可以在不影响流量测量精度的情况下改善多种鱼类在测量堰上的上游通道，这是世界各地鱼类洄游的常见障碍。还评估了各种 CBC 阵列密度对测量的影响。正如使用理论预测的那样，当阵列放置在流态从亚临界变为超临界的点的下游时，对测量没有影响。这项研究强调了交错排列的 CBC 可以在不影响流量测量精度的情况下改善多种鱼类在测量堰上的上游通道，这是世界各地鱼类洄游的常见障碍。还评估了各种 CBC 阵列密度对测量的影响。正如使用理论预测的那样，当阵列放置在流态从亚临界变为超临界的点的下游时，对测量没有影响。这项研究强调了交错排列的 CBC 可以在不影响流量测量精度的情况下改善多种鱼类在测量堰上的上游通道，这是世界各地鱼类洄游的常见障碍。