2D FAST Solver

Quick assessment of flooding using simplified hydraulics

The 2D FAST solver is an innovative flood inundation modelling tool designed to allow quick assessment of flooding using simplified hydraulics. It provides results in seconds or minutes, as opposed to hours or days, which are up to 1,000 times faster than traditional 2D models.

Key facts

  • Provides results for large scale studies in minutes

  • Rapidly estimates flood extent and depth from many sources of flooding, including coastal, fluvial, surface water and sewer flooding

  • Applicable to mapping flood risk at local, regional and national scale

  • Use in conjunction with more accurate methods, such as the 2D ADI solver

  • Reduces the cost of detailed modelling by identifying the flood risk ‘hot spots’ 

  • Can be used in probabilistic analysis frameworks

The 2D FAST solver allows modellers to rapidly estimate flood extents and depths from multiple sources of water, including tide, surge and fluvial overtopping or breaching of defences, surface water and sewer flooding.  Applications include near real-time flood inundation prediction on the Tidal Thames in London, England, through to prediction of areas susceptible to pluvial flooding for the whole of Scotland to mapping flood risk scenarios for the Philippines.

The speed with which the solver calculates water depths gives modellers the flexibility to rapidly test “what if” scenarios, explore uncertainty and probabilistic analysis, and evaluate the interactions and dependency between flood sources.

The 2D FAST solver works by identifying depressions on the floodplain then routing water through these depressions. Water depths in the depressions are determined by the volume of water flowing into each one and the water level in the neighbouring depressions. The solver is able to do this by adopting new ways of resolving the detailed hydraulics. 

2D FAST defence breach simulation with B

Explore 2D results in the core map interface, overlaid on the built-in background mapping and any other contextual layers. Extensive colour ramp options make it easy to understand your results and how they evolve over time.

The 2D FAST solver dynamically links to the 1D river solvers to enable an integrated modelling approach. Users can also switch between the 2D ADI and 2D TVD solvers when building models, enabling large and complex studies to be undertaken much quicker than previously possible.

Model outputs can be processed directly within Flood Modeller's user-friendly interface which provides an intuitive environment for building, running, and analysing 2D models. You can then share results with colleagues, clients or other stakeholders using a range of visualisation tools.