A culvert is a covered road structure constructed to pass flood and drainage. The engineering design principle of culverts focuses on optimising flood capacity at the lowest possible cost, resulting in high flow velocity through the barrel. With modern engineering design being more environmentally aware, culverts are considered common barriers for fish migrating upstream due to the excessive barrel velocity. The migration of fish upriver is important for their breeding and feeding activities, contributing to a stable population and species diversity. Improved or novel design for a fish‐friendly culvert is needed to ensure well‐being of local fish community. This article is a review of recent developments in seeking a solution for a better fish‐friendly culvert design. A major common feature of the reviewed studies is the application of hybrid modelling, combining laboratory experiments and numerical Computational Fluid Dynamics (CFD) modelling together. Various design alternatives were compared for pros and cons: channel roughening, installation of speed‐reducing structures (e.g., baffles or beams), and simply widening the channel by adding more culvert units (boxes). Overall, channel widening stands to be a better design choice due to its suitability for both flood passage and fish passage, with little impact on operation safety and a reduced maintenance cost.

中文翻译：

---

箱涵低速带的混合建模可帮助鱼类通过：为什么简单更好？

涵洞是经掩盖的道路结构，旨在通过洪水和排水。涵洞的工程设计原理着眼于以尽可能低的成本优化洪水容量，从而提高通过炮管的流速。随着现代工程设计更加注重环保，由于过大的桶速，涵洞被认为是鱼类向上游迁移的常见障碍。鱼上游的迁移对其繁殖和摄食活动至关重要，有助于稳定的种群和物种多样性。需要对鱼类友好的涵洞进行改进或新颖的设计，以确保当地鱼类群落的福祉。本文是对寻求更好的鱼类友好涵洞设计解决方案的最新进展的回顾。综述研究的主要共同特征是混合建模的应用，将实验室实验和数值计算流体动力学（CFD）建模结合在一起。比较了各种设计方案的优缺点：通道粗糙化，安装减速结构（例如，挡板或横梁）以及通过添加更多的涵洞单元（盒子）来简单地拓宽通道。总体而言，加宽河道由于适用于洪水通道和鱼类通道，对操作安全的影响很小，并且降低了维护成本，因此是更好的设计选择。挡板或横梁），并通过添加更多的涵洞单元（盒子）来简单地拓宽通道。总体而言，加宽河道由于适用于洪水通道和鱼类通道，对操作安全的影响很小，并且降低了维护成本，因此是更好的设计选择。挡板或横梁），并通过添加更多的涵洞单元（盒子）来简单地拓宽通道。总体而言，加宽河道由于适用于洪水通道和鱼类通道，对操作安全的影响很小，并且降低了维护成本，因此是更好的设计选择。