Flood hazard data provide an indication of the magnitude and probability of flooding. These data offer spatially static views of hazard (e.g. the 1-in-100 year flood everywhere).

To model flood hazard correctly, you need a range of hyper-resolution datasets and an understanding of relevant physical processes, including topography, channel locations and sizes, and the physics of flood wave propagation through channels and across floodplains.

In some areas of the world, such as the UK, there is a rich body of data that enables the creation of high-resolution, high-accuracy flood hazard datasets. However, in many other regions, data is scarce and so producing large-scale flood models that accurately represent these flood hazards is much more complex.

Fathom’s Flood Hazard Data & Maps

Fathom’s datasets solve some of the greatest challenges facing flood mapping and hydrology.

Global flood map

Global flood mapping from the cutting edge of scientific research.

Fathom-UK Flood Hazard Data

Comprehensive flood modelling for the whole of the United Kingdom.

Fathom-US Flood Hazard Data

A paradigm shift in our understanding of US flood risk.

Fathom-Japan Flood Hazard Data

Building on an extensive network of river gauges and flood defences.

The key components of building flood hazard datasets at a global scale.


Terrain data

These datasets define the topography of the Earth’s ground surface.

Data used

Fathom’s models are underpinned by the best globally available terrain datasets for flood modelling. Our global base data are currently being upgraded from MERIT-DEM to a new dataset based on the Forest and Buildings Removed Copernicus DEM (FABDEM). Our team collaborated in the creation of both ground-breaking datasets. Over certain parts of the globe even higher quality national terrain datasets are available, usually underpinned by laser altimeter data (LiDAR) or photogrammetry derived datasets. Wherever possible these national data are used, including across all of our country specific models.


Discharge estimation

Estimates of extreme river flows to drive the flood inundation model.

Data used

River discharge measurements from thousands of stream gauges globally in a statistical model alongside a multitude of other geospatial datasets.


River channels

Representation of the location and size of all rivers is a critical component in building accurate inland flood models.

Data used

MERIT Hydro globally, more accurate national data (e.g. NHD in US) where available, with our dynamic channel solver used to estimate bathymetry.



Large scale models must be automated. Manual building of models requires significant time and resource making it impossible to reproduce at continental and global scales.

Data used

Rapid algorithms developed in house by Fathom’s hydrologists.



Efficient inundation modelling

Equations that describe the movement of water quickly, yet with sufficient accuracy.

Data used

A hydraulic model developed across two decades at the University of Bristol by, now, Fathom scientists. By virtue of our open methods, most leading flood modellers throughout the world use some variant of this code.

Advancements in modelling global flood and the launch of Fathom-Global 2.0


During their time working at the University of Bristol Hydrology Group, Fathom’s co-founders focused on small scale two-dimensional flood models. These models had access to a huge amount of data enabling highly accurate flood predictions. However, they required manual data entry making it impossible to replicate at a large scale. This image is a simulation of a UK flood event that Fathom built over 10 years ago and is within error of a real-world event.

When first founded, it was Fathom’s mission to build models in areas of the world that struggled with data scarcity. This is one of the first models Fathom created.

In 2016 Fathom released its first global flood hazard dataset, Fathom-Global 1.0. The model explicitly modelled every river channel in the world – regardless of size. This is a key differentiator for Fathom’s global model within the marketplace.

It was in the release of Fathom-US 2.0 that Fathom truly made its name, with major publications such as The Wall Street Journal and Reuters covering the launch.

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Want to learn more about our flood hazard data?