Flooding, exacerbated by climate change and urbanization, is a growing global concern, with traditional flood defences often proving inadequate for long-term protection. Nature-based solutions (NbS), such as meander restoration and reforestation, have emerged as sustainable approaches to enhance flood resilience while simultaneously promoting ecological benefits.
This research explores how tributary re-naturalisation, specifically through meander restoration and reforestation, can improve flood management and landscape stability. Using the established computational flood model CAESAR-Lisflood, this study simulates the effects of various restoration scenarios over a 50-year period on two tributaries of the River Don catchment in northern England, examining how the location and distribution of tributary restoration projects influence downstream main channel flood risks and geomorphological stability.
The key findings show that tributary upstream meander restoration significantly reduces sediment transport and lateral erosion in the downstream main channel, contributing to improved long-term channel stability and more reduced high flood velocity area. Furthermore, upstream reforestation, especially in valley areas, also effectively mitigates flood risks by reducing total flood area, high-depth area and enhancing water retention. Consolidated projects, whether focused on meander restoration or reforestation, were found to be more effective than dispersed efforts, offering greater benefits in terms of flood mitigation and sediment control. Specifically, larger, consolidated projects performed better at reducing high-velocity flood zones and erosion risks.
These findings emphasize the importance of strategic upstream interventions for sustainable flood management and provide crucial insights for policymakers and practitioners. By prioritizing evidence-based strategies in large-scale, consolidated restoration efforts in upstream areas, decision-makers can optimize catchment management plans aimed at improving long-term flood resilience and geomorphological stability. This research supports the integration of nature-based solutions into long-term, catchment-scale flood management strategies, offering a sustainable alternative to traditional engineered flood defences.
