Mapping global flood risk

Research highlights

• Developed high-resolution flood-risk models that provide unprecedented detail and scale 
• Created powerful algorithms that dramatically speed up risk assessments  
• Provided data that supported global humanitarian efforts 
• Informed global flood-risk strategies of businesses and NGOs 

Flooding exacerbated by climate change is one of the world’s most destructive natural disasters, displacing millions, disrupting economies and disproportionately impacting vulnerable communities. 

The management of flood risk also poses complex challenges, requiring high resolution detail to guide effective action.

Professor Paul Bates and Dr Jeff Neal from Bristol’s Hydrology research group have responded by developing modelling tools capable of mapping the risks at resolutions as fine as one meter in urban areas and 90 meters at the global scale.  

This  level of detail is matched by unparalleled scope. While traditional models were only capable of covering smaller areas, Bristol’s tools can simulate flood risks at continental and global scales for any region of the world.

These advancements overcome limitations inherent in older models, which relied on detailed models and local data and were typically confined to developed nations. 

Powerful algorithms, computationally efficient 

To drive practical application, the research group has also developed a powerful set of algorithms that allow for flood-risk assessments that are 10 to 100 times quicker than the methods they replaced, significantly reducing the time and cost required for flood-risk assessments.  

For instance, the creation of a global flood-risk map at 90-meter resolution can now be completed in just two to three months on modern servers  compared to 20–200 months with older techniques.

This breakthrough further democratises flood modelling, making it accessible to countries with fewer resources and empowering them to better plan for and mitigate flood risks. 

Supporting communities, industry and NGOs 

The research has already influenced policies and practices worldwide. During Cyclones Idai in 2019 and Eloise in 2021, Bristol’s flood maps were vital for UK Government-funded humanitarians who were able to plan resources effectively and save lives in Mozambique.

The World Bank has employed Bristol’s data to guide resilience projects in countries like Bangladesh, Belize, and Vietnam.   

In the business world, Microsoft relies on the models to protect global cloud infrastructure and ensure continuity of services such as Teams and OneDrive during extreme weather events.  

Additional research conducted with The Nature Conservancy has demonstrated the economic benefits of preserving floodplains in the United States, influencing conservation priorities. 

To further broaden reach, the team spun off a company called Fathom in 2013. Acquired by Swiss Re in 2023, Fathom now distributes Bristol’s models globally, enhancing flood-risk management for governments, insurers and businesses worldwide. 

Building more resilient transport Infrastructure 

Urban infrastructure, particularly transport networks, is especially vulnerable to flooding. In a further strand of research, Dr. Maria Pregnolato and a team from the Faculty of Engineering are developing strategies to protect these vital systems.

Their research has included working with hydrologists, transport scientists, economists and urban scientists to understand vulnerabilities and the need for both ‘grey’ (e.g. flood wall) and ‘green’ (e.g. rain garden) measures in urban flood-risk management plans,  

Further work has included consultations with Network Rail.

This has explored how continuous monitoring technologies on rail bridges could allow for better mitigation against ‘scour’ - the primary  cause of bridge collapse which occurs when sediment is washed away from a bridge’s foundations during high and turbulent river flows. 

Mapping the future of flood management 

As climate change accelerates, the need for accurate, accessible flood-risk data has never been greater.

Bristol researchers continues to push boundaries, asking questions about whether there is racial or social bias to flooding, and exploring innovative solutions that bridge science, policy business and community needs.

Their work not only helps to mitigate flood damage but also drives global efforts to build a safer, more equitable future.