How to use the 2D Flood Calculator

Basic Operation

This function generates a grid or shapefile to represent a flood extent from 2D model data. The required input data are a selected time step (or multiple time steps) from a depth dataset produced by a 2D hydraulic model. Currently this can be either a TUFLOW format scalar depth output file, i.e. '_d.dat' or an 2D Model format scalar depth output file, i.e. '_depth.dat'. The flood calculator tool takes the specified input data and converts it to a depth grid format (.asc or .flt), a contour polygon shapefile or a google earth file (kml).

Alternatively you can export any other 2D model output parameter into ASCII grid format as well, i.e. water levels, flows or velocities. You can also choose to combine the depth and velocity data to produce a flood hazard data grid.

The Flood Calculator window can be accessed by selecting the 2D Flood map button from the Results tab.

To use the tool you should already have your desired input data, i.e. 2D results data, loaded in the Flood Modeller viewport. The flood calculator window contains two tabs, as shown in the figure below.

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These tabs provide tools to perform the following functions:

Export Map(s) Tab

Within the standard flood map export tab of the 2D Flood Calculator a number of options exist allowing you to tailor the flood map calculation to their specific needs. These options are:

Flood Volume Tab

The flood volume tab of the 2D Flood Calculator enables the calculation of flood volume, the number of wet cells and the wetted area for all time steps within your 2D model results. Note that this option requires the water depth 2D result to be loaded in your map view. The design of the Flood Volume tab is shown in the figure below. The table of time step, number of wet cells, wetted area and flood volume data can be saved to a comma-separated value text file (.csv file), which can then be viewed in other applications (e.g. MS Excel).

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