Characterising the impact of large wood in river restoration

Freshwater 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, geomorphic, 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. The overall aim of this project is to understand the conditions that maximise beneficial impacts of river restorations using LW-based solutions. Through a combination of field and remote analysis, and computational modelling, this PhD will 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 geomorphic conditions.