Rivers have been subject to the construction of numerous small-scale anthropogenic structures, causing the alteration and fragmentation of habitats. Despite their impact on fish habitat selection, migration, and swimming performance, more hydraulic structures are being added to riverine systems. These mainly have the purpose of harnessing renewable energy or mitigating the impact of flooding, as in the case of leaky barriers that are widely used for natural flood management. By providing a sustainable and cost-effective supplement to traditional hard engineering flood risk management methods, these channel-spanning wooden barriers are constructed using sustainable, local materials, intended to slow down surface water and groundwater flow, reduce flood peaks, and attenuate the flow reaching downstream communities. Despite their increasing popularity, little is known about the design implications on fish movement or hydrodynamics. Using scaled laboratory flume experiments we investigate how the physical design of four leaky barriers varying in porosity, length, provision of overhead cover, and color, impact on fish movement and spatial usage, and the channel hydrodynamics. Our fish behavioral analysis reveals that juvenile rainbow trout (Oncorhynchus mykiss) movement reduces with barrier presence. Upstream passage increases with barrier color but not cover, for shorter rather than longer leaky barriers, and for a non-porous barrier compared to its porous counterpart. Barrier-specific flow alterations appear to play a secondary role compared to barrier color. Our study showed that physical barrier design and leaky barrier presence alter fish movement, and therefore care needs to be taken during the design of such natural flood management structures.

中文翻译：

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物理渗漏屏障设计对虹鳟幼鱼（Oncorhynchus mykiss）运动影响的实验研究

河流受到无数小型人为结构的建设，导致栖息地的改变和破碎。尽管它们对鱼类栖息地的选择、迁移和游泳性能产生影响，但更多的水力结构正在被添加到河流系统中。这些主要目的是利用可再生能源或减轻洪水的影响，例如广泛用于自然洪水管理的渗漏屏障。通过为传统的硬工程洪水风险管理方法提供可持续且具有成本效益的补充，这些跨渠道的木制屏障使用可持续的当地材料建造，旨在减缓地表水和地下水流量，减少洪水高峰，并减弱流量到达下游社区。尽管它们越来越受欢迎，但对鱼类运动或流体动力学的设计影响知之甚少。我们使用按比例缩放的实验室水槽实验研究了四个渗漏屏障的物理设计如何在孔隙率、长度、顶盖的提供和颜色、对鱼类运动和空间使用的影响以及通道流体动力学方面发生变化。我们的鱼类行为分析表明，虹鳟鱼幼鱼 (Oncorhynchus mykiss ) 运动随着屏障的存在而减少。上游通道随着屏障颜色的增加而不是覆盖物增加，对于更短而不是更长的泄漏屏障，以及与多孔屏障相比，无孔屏障。与屏障颜色相比，屏障特定的流动变化似乎起着次要作用。我们的研究表明，物理屏障设计和渗漏屏障的存在会改变鱼类的运动，因此在设计此类天然洪水管理结构时需要小心。