Natural flood management
We work with our clients and partners to design natural flood management (NFM) measures that deliver efficient and sustainable solutions to their flood risk challenges.
Our team has specialist expertise in the flood risk impacts of natural processes such as vegetation growth, sediment transport and their interactions with hydraulics. We also understand the impacts of different management options, from soft to hard interventions, and have used our knowledge to develop guidance documents and design manuals.
We provide a tailored suite of approaches for our clients that consider technical and non-technical issues. We use advanced numerical and physical models, statistical approaches, earth observations techniques and participative approaches to develop optimised, resilient flood management solutions.
What is natural flood management?
Natural flood management (NFM) measures use natural processes to reduce flood risk in coastal and river environments. Natural flood management measures are part of a broader group of nature based solutions that we apply to address the sustainability, resilience and management of water resources. Working with nature improves biodiversity, creates and improves green spaces, improves water quality and helps to build more resilient ecosystems.
How does natural flood management work?
Natural flood management measures help to reduce flood risk by:
- Storing water in the river or the floodplains e.g. by improving the connection between these areas to encourage water retention;
- Storing runoff in the catchment, e.g. by creating flood storage areas;
- Increasing infiltration of rainfall into the ground, e.g.by changes in agricultural practices;
- Increasing evapotranspiration, e.g. by planting trees;
- Slowing the runoff in the catchment, e.g. using vegetation or hedgerows;
- Slowing water discharge in rivers and floodplains, e.g. by creating debris dams, etc;
- Reducing the volume of sediment deposited in a river, decreasing capacity, e.g. by changing in agricultural practices.
Integrated natural flood management measures
Individual measures are unlikely to have a significant effect on flood peaks and volumes. Natural flood management measures have the greatest impact when they are combined and used throughout a catchment. We use ‘integrated natural flood management’ to achieve significant flood reduction benefits. Our research has considered how flow volumes and hydrograph syncronisation of peak flows are affected by natural flood management measures. We can model the effects on flood risks of different natural flood management measures such as woody dams, riparian vegetation, hedgerows, offline and online storage areas and sediment ponds, and we use this to support the design, location and assessment of the effectiveness of integrated NFM measures.
International guidance on nature based solutions
Our experts have developed guidance on the use of nature flood management and green infrastructure.
- International guidelines on the development and implementation of natural and nature-based features developed in collaboration with the US Army Corps Engineers. These guidelines support the engineering functions of coasts and fluvial systems.
- Green approaches in river engineering: supporting implementation of Green Infrastructure brings together the strategic arguments and the technical information needed to support the selection of green approaches and, through a series of case studies, provides sound evidence on constructability, engineering performance and environmental and social benefits. Available as a free download.
- Implementing nature-based flood protection. Principles and implementation guide published by the World Bank.
Want to know more?
