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

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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.