Characterising the impact of large wood in river restoration (ref 4599)

项目背景由于气候变化和全球物种面临的物理压力，淡水生态系统正在衰落，全球河流系统的广泛破坏已导致栖息地和生物多样性的巨大损失。例如，这促使联合国生态系统恢复十年、《水框架指令》和《生境指令》采取紧急行动，保护和恢复河流环境，加强生境和集水区管理。大型木材(LW)是河流恢复的必要工具，积极促进重建自然过程和河流系统的生物多样性。LW材料越来越多地被用于河流的各种目的，如自然洪水管理、洪泛区重建和生境改善。尽管河流恢复和全球日益增长的兴趣(和投资)的重要性，但对影响基于LW的河流恢复解决方案在哪里以及如何应用的水力、水文、地貌和社会条件的了解仍然非常有限。此外，还不清楚i)不同河流中不同的LW所提供的益处以及在当地和集水区范围内随时间发生的任何变化，ii)哪些建模工具可以预测LW恢复措施的影响，iii)应如何设计LW并将其用于河流恢复项目。学生将通过现场和远程分析、计算模型和水槽实验相结合的方式分析河流恢复方案的水流和泥沙响应，针对一系列不同的LW解决方案以及河流类型和水流，以解决关键的研究问题和行业需求，例如：应该利用什么LW规模和数量；什么是河流类型的最佳LW配置；什么是能够提供鱼类通过的合适的LW解决方案。这将促进对当地和流域尺度的社会、水力、水文和地貌条件变化的理解。这项研究的结果将导致在河流恢复中使用LW以改善河流的水文地貌和生物多样性的最佳实践指南，该指南可以通过河流恢复社区广泛传播，并将纳入现有的指南。该项目将支持一种灵活的方法，以满足成功候选人的兴趣，并鼓励学生在埃克塞特大学和卡迪夫大学水实验室设计数据分析、建模和水槽实验，以最适合他们的研究方向。

Project BackgroundFreshwater ecosystems are declining due to climate change and physical pressures on species worldwide, whereby extensive damage to river systems across the globe has driven to a huge loss of habitat and biodiversity. This has prompted, for example, the UN Decade on Ecosystem Restoration, the Water Framework Directive and the Habitat Directive to compel urgent actions to protect and restore riverine environments, enhance habitat and catchment management. Large wood (LW) is an essential tool for river restoration, actively promoting the re-establishment of natural processes and biodiversity of river systems. LW material is increasingly used in rivers for a variety of purposes such as Natural Flood Management, Floodplain Reconnection, and habitat enhancement.Despite the importance of river restoration and global growing interest (and investment), there is still very limited understanding of the hydraulic, hydrological, geomorphological, and social conditions that influence where and how LW-based river restoration solutions can be applied. Moreover, it is unclear i) the benefit provided by different LW in different rivers and any changes over time, both at local and catchment scale, ii) what modelling tools can predict the impact of LW restoration measures, iii) how LW should be designed and used in river restoration projects.Project Aims and MethodsThe overall aim of this project is to understand the conditions that maximise beneficial impacts of river restorations using LW-based solutions. The student will analyse the flow and sediment response to river restoration schemes through a combination of field and remote analysis, computational modelling, and flume experiments, for a broad set of different LW solutions, and river types and flows, to address key research questions and industry needs, such as: what LW size and quantity should be utilised; what is the optimum LW configuration for river type; what are suitable LW solutions that can provide fish passage. This will advance the understanding of local- and catchment-scale changes on social, hydraulic, hydrological, and geomorphological conditions.The results from this research will lead to a best-practice guidance for use of LW in river restoration to improve the hydromorphology and biodiversity of rivers, that can be disseminated widely through the river restoration community and will build into existing guidance. This project will support a flexible approach to match the interest of the successful candidate, and the student will be encouraged to design data analysis, modelling, and flume experiments at both the University of Exeter and the Cardiff University HydroLab to best suit their research direction.