• 27 Jun 2024
  • 2 Minutes to read
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Article summary


ReFH2 enables estimation of design and observed flood hydrographs for rural and urbanised catchments across the UK using ReFH2 software from Wallingford HydroSolutions

The ReFH2 tab in a Calculation point allows you to perform these analyses to calculate the hydrographs, and save the results to the Calculation point ready for further review. Multiple ReFH2 analysis can be undertaken and saved in a calculation point (for example, if hydrographs are required for several storm durations). Once analysis is complete, results can be viewed within Flood Modeller without an ReFH2 licence.

User Caution
While ReFH2 provides a framework for flood hydrograph estimation, it is important that you have the appropriate technical and regulatory knowledge required to use the software effectively. Further guidance is referenced here.

Creating a new analysis

To start a new ReFH2 analysis, click the Initiate new analysis button. You must have an ReFH2 licence (and must have ReFH2 installed on your machine). The software will open ready for you to start your analysis. Further details of how to use ReFH2 are provided by Wallingford HydroSolutions here: Online Tutorials for ReFH 2 - WHS (

Once you've completed the ReFH2 analysis, click to Save to Flood Modeller and choose whether to export CSV results, PDF report or Both, the default is CSV results. Then in the File menu, select Exit to Flood Modeller. This will close ReFH2 and allow you to save the analysis within your calculation point.

Saving analysis from ReFH to Flood Modeller
Export Options

Once ReFH2 exits, Flood Modeller will ask for details of the analysis to import. The time and data of analysis alongside the user who undertook the work will automatically be populated with optional fields for analysis name and user comments.

Flood Modeller displays detailed information for each return period (including rainfall, baseflow components), with return period of interest selected via a drop down menu. Users can also choose between displaying urban or rural hydrographs. The software can also plot simplified details for all hydrographs if All is selected in the return period menu. If a WINFAP analysis has been undertaken, peak flow estimates can be overlaid over hydrographs for context under the WINFAP Distribution menu.

Selecting an analysis

Multiple ReFH2 analyses can be saved to each calculation point. To select an ReFH2 analysis to use in your session, use the Set As Preferred toggle. This version then becomes the default ReFH2 analysis the software will use, for example when reconciling the hydrographs.

For each analysis, the data is plotted on the right-hand-side of the tab. A toolbar provides options to select which data to view, and to customise the appearance of the plot. Full details of all options provided within ReFH2 tab are provided in the Calculation Points technical reference.

Exporting ReFH2 data

For each analysis run, an Export ReFH2 to csv button is available. The exported design rainfall can be used as input to your 2D simulations. Full details on this can be found in this article on Using H+ outputs in simulations.

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