Global flood risk is expected to increase due to climate change and development in areas at risk. Actions can be taken to manage these risks and reduce the impacts on our physical and naturally built environment. To inform these actions and allow investment in risk management to be prioritised effectively, the availability of accurate, timely and scalable flood mapping is essential.

However, generating efficient flood models at scale is not easy. It requires the use of cutting edge technology and analytical techniques to produce and analyse petabytes of data.


JFlow®, our 2D hydraulic model, is our answer to this problem. It solves the shallow water equations using graphics processors (or GPUs) to perform the calculations. This delivers speed advantages of 10 – 100x quicker over regular computer processors.

We led the way in running flood models on the GPU. Others have followed (e.g. WBM-BMT, CH2M and HEC), as they see the capabilities that the technology offers.

JFlow® is applied throughout the lifecycle of flood related civil engineering and construction projects.

Master planning

JFlow® was used to determine the effects of levee setback and gate operations on the agroecology of the Sacramento (California, USA) floodplain. The large catchment based models were run in days instead of months, allowing clients to consider more options than normally possible.

Operations and Maintenance (O&M) Optimisation

JFlow® was used to optimise the O&M regime for over 100,000 culverts owned by local authorities and infrastructure operators (e.g. Network Rail). Using a risk-based approach, investments could then be made where activities contributed most towards reducing the potential for damage, and where it was economically and environmentally justified.

Emergency Planning

We ran 1.2 million models for the Environment Agency to create a novel way of producing Real Time Flood Impact maps. This innovative approach allows more accurate and timely flood analysis. This is particularly important for improving the warnings given to communities and businesses, and in determining the emergency responses of category 1 and 2 emergency responders.

Proactive Response

Through the application of JFlow®, we have established a new business in the (re)insurance sector. We are now one of the leading providers of natural hazard modelling services, helping our clients manage risk and respond more quickly and effectively. We have:

  • Modelled 600,000+ events in our probabilistic models
  • Produced 153,000+ hydrological accumulation zones across the globe
  • Modelled 288,500km of river in our European Flood Model (EFM)
  • Produced 36 million km2 defended areas in our EFM
  • Developed the most comprehensive natural peril datasets in the world.


To enable these projects, we have invested heavily in our JFlow® Grid of computers for processing and analysing these “Big” datasets. We run approximately 400,000 stream processors, resulting in 1.1 petaFLOPS (10^15 calculations/second) of computing power, which puts it in the super computer league.

Our JFlow® software and the JFlow® Grid enables our clients to produce:

  • Models with increased resolutions capturing more detail of the environment being modelled
  • Models with much larger areas than previously possible – our latest models and hardware can model areas of 1.76 billion cells
  • Monte-Carlo based simulation types, comprising of 100s or 1000s of permutations.

Want to know more?

For more information on this project contact Matthew Tancock or Rob Berry. You can also find out more about our work on our Systems, Software and Data web pages.

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