High-Resolution Elevation Data Availability

Accurate terrain data is essential for realistic flood simulation. FastFlood supports a wide range of high-resolution Digital Elevation Models (DEMs) that form the foundation of its physically based computations.Where available, FastFlood automatically integrates national or regional high-resolution DEMs to improve local accuracy. These datasets include:

Resolution (m)	Countries
1	Dominica, Germany, Luxembourg, Belgium, Denmark, the United Kingdom, Austria, the Netherlands, and New Zealand
2.5	Australia
5	France, Spain, Romania, and Portugal
10	United States, Saint Vincent and the Grenadines, Saint Lucia, and Italy

Global Integration and Seamless Transitions

Beyond these national datasets, FastFlood includes access to global datasets such as:

• The Copernicus 20 m Global DEM offering near-complete global coverage at consistent resolution.

• The FastFlood Ensemble DEM, a composite terrain model created by intelligently blending multiple global datasets (including SRTM, Copernicus, and NASADEM) to minimise noise and fill data gaps.

All datasets are automatically harmonised within the FastFlood environment. The model seamlessly integrates multiple resolutions and data sources into a single, consistent elevation surface. This ensures no discontinuities or artefacts at country borders, even where datasets of different origins or resolutions meet.