Refactoring the SWMM 5 Help File – Files in SWMM5

Files in SWMM5

Files Used by SWMM

This section describes the various files that SWMM can utilize. They include:

· Project File
· Report and Output Files
· Rainfall Files
· Climate File
· Calibration Data Files
· Time Series Files
· Interface Files

The only file required to run SWMM is the project file; the others are optional.

Rainfall Files

SWMM's rain gage objects can utilize rainfall data stored in external Rainfall Files. The program currently recognizes the following formats for storing such data:

· 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.

When requesting data from NCDC’s online service, be sure to specify the TEXT format option, make sure that the data flags are included, and, for 15-minute data, select the QPCP option and not the QGAG one.

An excerpt from the user-prepared format might look as follows:

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.

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

Calibration Files

Calibration Files contain measurements of variables at one or more locations that can be compared with simulated values in Time Series Plots. Separate files can be used for each of the following:

· Subcatchment Runoff
· Subcatchment Groundwater Flow
· Subcatchment Groundwater Elevation
· Subcatchment Snow Pack Depth
· Subcatchment Pollutant Washoff
· Node Depth
· Node Lateral Inflow
· Node Flooding
· Node Water Quality
· Link Flow
· Link Velocity
· Link Depth

Calibration files are registered to a project by selecting Project >> Calibration Data from the Main Menu(see Registering Calibration Data).

The format of the file is as follows:

1. The name of the first object with calibration data is entered on a single line.
2. Subsequent lines contain the following recorded measurements for the object:
· measurement date (month/day/year, e.g., 6/21/2004) or number of whole days since the start of the simulation
· measurement time (hours:minutes) on the measurement date or relative to the number of elapsed days
· measurement value (for pollutants, a value is required for each pollutant).
3. Follow the same sequence for any additional objects.

An excerpt from an example calibration file is shown below. It contains flow values for two conduits: 1030 and 1602.Note that a semicolon can be used to begin a comment. In this example, elapsed time rather than the actual measurement date was used.

;Flows for Selected Conduits

;Conduit Days Time Flow


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