An overview from Professor Dan Parsons, Director – Energy & Environment Institute, University of Hull
Nature based solutions have a crucial role to play in making our places more climate resilient. They can contribute to addressing the impacts of climate change and aid sustainable development objectives such as enhanced biodiversity. For the purposes of this blog we are focussing our attention on the solutions offered by Natural Flood Management (NFM). NFM techniques can support flood and coastal resilience and improve water supply and have become a hot topic with rural communities and agencies assembling to build NFM solutions such as leaky dams in river channels. There has been a lot of media coverage around the reintroduction of beavers to UK habitats and the role they can play in slowing the flow of water through the landscape.
Join the Flood Innovation Centre’s interactive, online NFM workshop series to learn more about opportunities for your business – starting 12 May 2021
NFM can be developed in both rural and urban settings and might include reconnecting a river with its natural floodplain or introducing green infrastructure and sustainable drainage systems (SuDS) to reduce surface water flooding.
In a fluvial (river-based) context, NFM aims to enhance natural catchment processes to manage the propagation of flood waters, ultimately attenuating volumes and reducing peak flows. Although the effectiveness of NFM measures on peak water discharges at the local scale is reasonably well established, the longer-term and broader catchment-scale impact of NFM measures yields significant uncertainty in Flood Risk Management (FRM). In other words, it is critical to take a whole catchment approach to fully assess the impact of an NFM intervention to quite literally prevent storing up problems in the future (and downstream).
Catchments are interconnected systems, with differing channel capacities and non-stationary flood-risk properties – higher intensities of rainfall along with shifting/moving river beds – which affect catchment connectivity and how river systems will evolve over time. NFM measures will impact this water and sediment discharge connectivity through basins and in turn affect geomorphological processes and how sediments are carried through the river channel. Over time, the movement of silts and sediments affects the capacity of the channel, and the flood conveyance and ultimately impacting flood risk. Understanding the influence of hydrologic and geomorphic (sediment flux) drivers of system interconnectivity is vital in order to:
- accurately quantify catchment-scale changes in flood hazard and risk
- fully understand the influence of NFM at catchment scales over the range of flow discharges and over the long term
Establishing an understanding of the cumulative effect of flow-sediment interconnections and the longer-term impact of NFM on water and sediment flux across the catchment scale, over a range of different size basins is key to enabling optimisation and roll out of NFM measures across the UK.
The Challenge
In approaching any NFM intervention, it’s critical to:
- Assess flood risk for events of different magnitude and the impact and effectiveness of NFM approaches across catchment scales.
- Determine impact of NFM interventions on water and sediment fluxes – through a generic understanding of NFM connectivity.
- Examine interaction, clustering and optimisation strategies for NFM at various scales to maximise impact in reducing flood risk whilst maintaining flows during drought periods.
- Assess the longer-term influence and trajectories of NFM interventions on the evolution of basin connectivity, particularly in terms of sediment routing and responses in channel capacity including channel stability.
Solutions
Opportunities for the development of the solutions to approach these challenges could involve:
- A comprehensive dataset on NFM efficacy in terms of flow-sediment connectivity.
- Physical experiments for testing the efficacy and evolution of NFM across a range of spatial and temporal scales.
- A novel and robust predictive modelling framework and toolkit for efficiently investigating NFM strategies and NFM optimisation of implementations.
- A set of analytical tools for testing NFM outcomes in the context of changing magnitude and frequency of events.
Building on its international standing in flood research, the University of Hull has established the Flood Innovation Centre (FIC) to provide a hub for research and innovation focussed on flood risk and resilience. The £3.4m Centre is part funded by the European Regional Development Fund and based within the University’s Energy and Environment Institute. It supports small and medium sized enterprises to innovate flood resilience, mitigation, management and response solutions.
From 12 May 2021, FIC is delivering a five-week Natural Flood Management workshop series, aimed at SMEs who are looking to innovate, deliver or develop NFM solutions. In order to access the fully-funded (free to your business) workshop series, please visit the NFM Workshop Series page to register.