Importing rainfall data

Step-by-step guide

Rainfall events, also referred to as storms, are the most common inputs that are added to ICM models. There are two main types of rainfall data that can be used in InfoWorks ICM: Observed and Design.

Observed—or recorded—rainfall data represents actual rainfall events. These events can cover a single storm or multiple storms over a long period of time. Recorded rainfall data is normally used to calibrate the model and verify its correct operation against data collected during flow surveys, or against flood records for large historical storms.

Design rainfall storms represent the statistical characteristics of rainfall. They are derived from the analysis of many years of actual rainfall records. They are simpler to use than observed rainfall and can approximate the rainfall of a region in just a few storms.

In this tutorial, both types of rainfall events are created or imported in the model.

Before importing event files, it is a good idea to create a new model group to store all event data.

1. From the Explorer window, right-click the existing Model Group and select New InfoWorks > Model Group.
2. In the New Name - Model Group popup, name the group "Ancillary Files".
3. Click OK.

To create a design rainfall event:

4. From the Model Group, right-click the Ancillary Files group and select New InfoWorks > Rainfall Event.

5. In the New Name - Rainfall event popup, enable Generate Design Rainfall.
6. Add a name of "M5-60".
7. Click OK.
8. In the Select an Event Generator popup, select United Kingdom Rainfall for the purposes of this tutorial.

9. Click OK.
10. In the Rain Event Generator Parameters dialog box, in the Event group, set the Return period to 5 years, and the Duration to 60 minutes.
11. Expand the Profile drop-down and select Summer.

12. Click OK to save the changes.
13. From the Model Group, Ancillary Files group, right-click M5-60 and select Open As.
14. From the Select Format popup, select Grid Editor.
15. Click OK.

The Rainfall event for the M5-60 storm appears in a grid format. Note the tabs for setting the antecedent conditions. These supersede any settings in the model or sub-event properties.

16. When finished reviewing the data, Close the Rainfall Event Editor.

The design rainfall data can also be viewed in a graph format.

17. In the Ancillary Files group, right-click M5-60 again and select Open As.
18. From the Select Format popup, select Graph.
19. Click OK.
20. Resize the graph window to better read the results.

21. Close the graph window.

To import an observed rainfall event, which is frequently contained in a spreadsheet:

22. From the Model Group, right-click Ancillary Files and select Import InfoWorks > Rainfall event > from InfoWorks format CSV file.

23. In the Open dialog box, navigate to the folder with the downloaded files for this tutorial.
24. Select 2001 Typical Year_Evap .csv.
25. Click Open.
26. To view the rainfall in graph form, from the Model Group, right-click the event and select Open as > Graph.

27. To edit the event, right-click 2001 Typical Year_Evap and select Open as > Editor.

The Rainfall Event profile has a column header of 1 (mm/hr). This means the rainfall is applied to subcatchments with a Rainfall Profile of 1. Note the tabs at the bottom of the window, such as Evaporation Data. These can be used to set additional parameters such as time-varying evaporation profiles for use during the event, or to set individual starting conditions for individual surfaces.