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Entering Known Rainfall Precipitation Data

Product(s): CivilStorm, SewerGEMS
Version(s): CONNECT Edition
Area: Layout and Data Input


How can I model a storm event to get appropriate catchment runoff into my model, based on known rainfall precipitation data over a certain period of time?


If your rainfall data is in a supported format, it can be imported as a Rain File Storm Event. This is done by going to Components > Storm Events. Select the New icon and choose Rain File. Click the ellipsis (“…”) button next to the item “Rain File” on the right and browse to the rain file being used. Change the items “Rain Data File Type” and “Rain Units” as needed. In the table on the right, enter a label, the return event (in years), the Station ID (which should be in the rain file), and the time increment from the rain file.

Note that you would typically use the EPA-SWMM Runoff method for your catchments and the Explicit (SWMM) numerical solver, when using rain file data for a long term simulation. (see more below)

Supported Rain File Formats

The following standard formats are supported for rain files:

  • Hourly and fifteen minute precipitation data from over 5,500 reporting stations retrieved using NOAA's National Climatic Data Center (NCDC) Climate Data Online service ( (space delimited format only).
  • The older DS-3240 and related formats used for hourly precipitation by NCDC.
  • The older DS-3260 and related formats used for fifteen minute precipitation by NCDC.
  • HLY03 and HLY21 formats for hourly rainfall at Canadian stations, available from Environment Canada at
  • FIF21 format for fifteen minute rainfall at Canadian stations, also available from Environment Canada.
  • A standard user-prepared format where each line of the file contains the station ID, year, month, day, hour, minute, and non-zero precipitation reading, all separated by one or more spaces.
    • See screenshot below for an example of this type

See Also

Running a Long Term Continuous Simulation