Using MODFLOW Native Files

If you have been using MODFLOW with GMS for any amount of time, you have likely noticed that GMS uses a modified version of the MODFLOW files. This is so that the MODFLOW files can be used more efficiently by the GMS interface.

However, there are times when a project may require using the native MODFLOW files. This is often necessary when opening a MODFLOW project that was not originally created in GMS, or when sharing a project with someone who does not have access to GMS.

When importing native MODFLOW files into GMS, there are some important concepts to keep in mind:

• You will need to start by importing either the NAM file or MFN file. These files contain a directory for the other files in the MODFLOW project and how they should be opened.
• It is important to keep all of the MODFLOW files together in the same directory. Having only the NAME or MFN file will not be enough to open the MODLOW project.
• Files for the packages used with the project will typically have a file extension that matches the package. For example, the Wells package will have the extension "*.wel".
• All native MODFLOW files can be opened and reviewed using a text editor if needed. See the MODFLOW user guide for information on the file format.

Native MODFLOW files can be exported from GMS by turning on the Save Native Text Copy option in the MODFLOW Global/Basic Package dialog. When exporting native MODFLOW files, keep the following in mind:

• GMS will create a separate directory with the native MODFLOW files. This directory will typically be the project name with "_text" appended to it. For example, if the project is named "Aquifer", the directory will be named "Aquifer_text".
• All files in this directory should be kept together.
• As mentioned before, the files can be reviewed using a text editor.

With GMS 10.4, MODFLOW 6 native files can be imported and exported.

Being able to use native MODFLOW files can greatly enhance collaboration with projects. Try out importing and exporting native MODFLOW files in GMS today!