Data from: A toolkit for optimizing fish passage barrier mitigation actions

1. The presence of dams, stream–road crossings and other infrastructure often compromises the connectivity of rivers, leading to reduced fish abundance and diversity. The assessment and mitigation of river barriers is critical to the success of restoration efforts aimed at restoring river integrity. 2. In this study, we present a combined modelling approach involving statistical regression methods and mixed integer linear programming to maximize resident fish species richness within a catchment through targeted barrier mitigation. Compared to existing approaches, our proposed method provides enhanced biological realism while avoiding the use of complex and computationally intensive population/ecosystem models. 3. To estimate barrier passability quickly and at low cost, we further outline a rapid barrier assessment methodology. The methodology is used to characterize potential passage barriers for various fish species common to the UK but can be readily adapted to different planning areas and other species of interest. 4. We demonstrate the applicability of our barrier assessment and prioritization approach based on a case study of the River Wey, located in south-east England. We find that significant increases in species richness can be achieved for modest investment in barrier mitigation. In particular, dams and weirs with low passability located on mid- to high-order streams are identified as top priorities for mitigation. 5. Synthesis and applications. Our study shows the benefits of combining a coarse resolution barrier assessment methodology with state-of-the-art optimization modelling to cost-effectively plan fish passage barrier mitigation actions. The modelling approach can help inform on-the-ground river restoration decision-making by providing a recommended course of action that best allocates limited resources in order to restore longitudinal connectivity and maximize ecological gains.

1. 水坝、溪流-道路交叉构筑物及其他水利基础设施往往会损害河流连通性（river connectivity），进而导致鱼类丰度与物种多样性降低。对河流拦阻物（river barriers）开展评估与修复治理，是恢复河流完整性的修复工程取得成功的关键所在。
2. 本研究提出一种结合统计回归方法（statistical regression methods）与混合整数线性规划（mixed integer linear programming）的综合建模路径，可通过针对性实施拦阻物治理措施，最大化流域（catchment）内土著鱼类物种丰富度（resident fish species richness）。相较于现有研究方法，本方案在提升生物学合理性的同时，规避了复杂且计算资源消耗巨大的种群/生态系统模型（population/ecosystem models）的使用。
3. 为实现低成本、高效率的拦阻物过鱼能力（barrier passability）评估，本研究进一步提出一套快速拦阻物评估方法论。该方法可用于刻画英国本土常见鱼类的潜在过鱼障碍特征，且可灵活适配至不同规划区域与其他目标鱼类物种。
4. 本研究以英格兰东南部的韦伊河（River Wey）为案例研究对象，验证了所提出的拦阻物评估与优先级排序（prioritization）方法的适用性。研究发现，仅需投入适度的拦阻物治理资金，即可实现鱼类物种丰富度的显著提升。其中，分布于中高等级溪流、过鱼能力低下的水坝与堰坝，被确定为优先治理的核心对象。
5. 综合与应用。本研究证实，将粗分辨率（coarse resolution）拦阻物评估方法与前沿优化建模（state-of-the-art optimization modelling）技术相结合，可实现鱼类过鱼拦阻物治理行动的低成本高效规划。该建模路径可通过制定最优行动方案，合理分配有限的治理资源，以恢复河流纵向连通性（longitudinal connectivity）并最大化生态效益，从而为河流修复的实地决策提供科学参考。