Problem

When trying to import an EPANET .INP file into WaterGEMS or WaterCAD or an SWMM 5 .INP file in SewerGEMS or CivilStorm, the import fails and/or a message similar to the below appears:

1) "The specified EPANET file could not be loaded. Error message: The specified EPANET file contains values with no section. Format does not follow EPANET standards."

2) Error: Key in dictionary: #### Key being added: ##### (where # is some number) 

3) There is a formatting error in the SWMM input file.

4) When importing an .INP file (EPANET) the model doesn't  display correctly. For example, all the junctions in the model file are at a 0, 0 location.

5) The program crashes with a dialog titled "Assertion Failed"

6) Missing pipes when exporting to EPANET (see "see also" below)

Background

These issues may occur in some cases where the EPANET or EPASWMM file is in an older format or if it was created from a third-party software that did not properly export the file (or exported it with non-standard formatting).

Note:

• If you only have a .net file, you need to first export that to .INP format by opening it in EPANET (free download), then go to File > Export > Network. This will save to .INP format.
  
  
• The EPANET 2.2 INP file format is supported (import and export) starting with WaterGEMS, WaterCAD and HAMMER 2023.

Solution - EPANET (WaterCAD / WaterGEMS / HAMMER)

Typically, software developers verify the "correctness" of their exported format by importing a model into EPANET 2 and checking hydraulic results. The issue with this approach is that EPANET 2 itself supports older INP formats and upon opening an INP in EPANET 2, if it detects such older file formats it does silent updates to convert the data into EPANET 2 format. So it is possible that if a model is exported from a third-party software but in an older format, that the .INP file may not fully work in WaterCAD/WaterGEMS, which is designed to support the official EPANET 2 format.

The following steps should help with most cases of this issue:

1) Open the file in EPANET and do a "File > Save As" to rename it just to be sure the filename isn't an issue. This saves the file in .NET format.

2) Then in EPANET do a "File > Export > Network", which saves the file back to a .INP format. This new INP file opened in WaterCAD/WaterGEMS through the File > Import > EPANET process.

Opening the file in EPANET may also reveal clues about any formatting problems that may cause problems with the WaterCAD/WaterGEMS import. For example you may be presented with a dialog listed various error codes. In one example, the "Assertion Failed" error was found to be caused by spaces in the node names, which were listed as error code 203 when the INP file was opened in EPANET.

Note: if all elements appear to import in the same location in WaterCAD/WaterGEMS/HAMMER, this could be due to decimal precision of the node coordinates during INP format data exchange. Open the model in EPANET and note the coordinate of a few of the elements. If the model was not drawn to the correct scale (and perhaps user defined pipe lengths used), decimal precision/truncation may cause the coordinates to all be equal on import.

Solution - EPA-SWMM (SWMM 5 - SewerGEMS / CivilStorm)

This section applies to import and export of SWMM 5 INP files in SewerGEMS and CivilStorm.

First, if you're using an older version of SewerGEMS or CivilStorm, there could be issues with data exchange with newer versions of EPA-SWMM. For example V8i SELECTseries 4 and below may not be able to work properly with EPA-SWMM 5.1 files. More robust support for SWMM 5.1 was added starting with V8i SELECTseries 5. SewerGEMS and CivilStorm 10.03.04.53 do not support SWMM 5.2, but a future version may.

Also, if you are in SewerGEMS for ArcGIS Pro, opening an INP file is done through the standard "Attach existing model" option (INP will be in the list of available file types, alongside .stsw).

Here is one possible symptom when importing a file created in a newer version of SWMM:

SWMM Import failed - "There is a formatting error in the SWMM input file.  Check line 13 in section [OPTIONS]. Line: """

In case the SWMM 5 .INP file contains non-standard formatting or other problems, which could be caused by the application that exported the file. Try checking it and re-saving it in EPASWMM itself:

1) Open the .INP file in EPA-SWMM itself (5 or 5.1). note any errors, which may be due to problems with the program that exported the file. 

2) Try computing the model in SWMM and note any additional calculation errors, which may be a result of any errors you saw when opening the file (which as mentioned above could be due to how it was saved).

3) Check for the following conditions:

• Patterns assigned to outfalls - remove these in EPA-SWMM as they are not supported in SewerGEMS or CIvilStorm.
• In one of the cases, there was problem with formatting of the climate file referenced in EPA-SWMM, after removing reference of that climate file, .INP file can be imported in SewerGEMS without any error. However it is recommended to edit and correct the climate file, check for formatting and then reattach it in EPA-SWMM and then re-export the file. 

4) If there are no problems with #1, 2 or 3 above, go to File > Save As and save to a new name (INP format)

"There is a formatting error in the SWMM input file" - this can happen if the INP file being imported was saved in a newer version of EPA-SWMM. For example a SWMM 5.2 file attempting to be opened in an unsupported version of SewerGEMS like 10.03.04.53. Future versions may add SWMM 5.2 support - reference # 869595.

See Also

Missing pipes when exporting to EPANET

Importing or exporting to WaterCAD, WaterGEMS, or HAMMER from other software

What are the differences between WaterGEMS/CAD and EPANET?