SWMM - Rain File

SWMM rain gage objects can use rainfall data stored in external rainfall files. The program currently recognizes the following formats for storing this data:

• Hourly and fifteen-minute precipitation data from more than 5,500 reporting stations retrieved using NOAA's National Climate Data Center (NCDC) Climate Data Online service (www.ncdc.noaa.gov/cdo-web) (space-only delimited format )
• Old DS-3240 and related formats used for hourly precipitation by NCDC
• Older DS-3260 and related formats used for fifteen minute fallout by NCDC
• HLY03 and HLY21 formats for hourly rainfall at Canadian stations, available from Environment Canada at www.climate.weather.gc.ca
• FIF21 format for fifteen-minute rain in Canadian stations, also available from Environment Canada
• A user-prepared standard format in which 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
  A user-prepared form snippet might look like this:

  STA01 2004 6 12 00 00 0.12
  STA01 2004 6 12 01 00 0.04
  STA01 2004 6 22 16 00 0.07
  

  
  This format can also accept multiple stations within the same file.

Note: When requesting data from the NCDC online service, be sure to specify the TEXT format option, ensure the data flags are included, and for 15 minute data select the QPCP option and not QGAG

When a rain gage is designated to receive its rainfall data from a file, the user must provide the name of the file and the name of the recording station referenced in the file. For the user-prepared standard format, the type of rain (eg intensity or volume), recording time interval and depth units must also be provided as rain gage properties. For the other file types, these properties are defined by their respective file formats and are automatically recognized by SWMM