Groundwater Modeling System (GMS) 6.0

Software review by courtesy of IGWMC and CSM
By Raymond H. Johnson, Ph.D.,
Hydrogeologist with the USGS (
Any mention of trade names does not imply any endorsement by the author or the USGS

GMS (Groundwater Modeling System) is a comprehensive software package for developing computer simulations of groundwater problems (flow and contaminant transport).  The Environmental Modeling Research Laboratory (EMRL, at Brigham Young University in Utah oversees the continued development of GMS (currently at version 6.0), but GMS is distributed commercially through a variety of vendors.

GMS provides tools for site characterization, model development, post-processing, calibration, and visualization. It supports TINs, solids, borehole data, 2D and 3D geostatistics, and both finite element and finite difference models in 2D and 3D, including MODFLOW, MODPATH, MT3D, RT3D, FEMWATER, SEEP2D, ART3D, MODAEM, SEAM3D, and UTCHEM.  Parameter estimation is supported through the processes included with MODFLOW-2000, PEST, and UCODE.

GMS’s design, allows the user to select “modules” in custom combinations.  These modules are related to pre- and post-processing, model selection, and calibration routines. Discussion of all modules is beyond the scope of this review, but many commercial vendors have websites with detailed descriptions of each module and how they can be used (search on GMS 6.0).  New users can select specific modules for a current project and add modules as needs expand or change.  Use of GMS saves time by having a modeling “package” that is the same for a variety of programs. The initial learning curve is steep. However, GMS uses the same “conceptual model” approach (discussed below) for alternative modeling programs (e.g., MODFLOW and FEMWATER).  

A “conceptual model” approach is built into the map/GIS module.  Here, a user defines the model properties (i.e., boundary conditions, hydraulic conductivity values, 2D and 3D model domain, etc.) in a GIS interface that is independent of the simulation codes. With a click of a button, model properties are transferred from the GIS interface to the appropriate grid cells or mesh elements.  The advantage of this approach is the ability to quickly change a conceptual model, transfer these conditions to a new simulation, and evaluate the results. In addition, GMS allows more advanced users to easily see and edit the grid by grid values, without going to the final text file (although a quick check of the text files is always a good idea). GMS 6.0 can be fully integrated with ArcGIS if the user also has an ArcGIS license, allowing for a seamless transfer in creating conceptual models and producing final figures of modeling results.

While GMS has excellent modular, visualization, and conceptual model development capabilities, its complexity causes some disadvantages.  My first version of GMS 6.0 was not as seamless with the ArcGIS interface as promised.  While technical support did their best to solve the problem, a solution was not immediately available. The best alternative was to wait six months until all the “bugs” were worked out and a download of the revised version solved the problems.  Similarly, the graphical interfaces in GMS 6.0 that go with the calibration and parameter estimation routines are recent additions and my last version of GMS 6.0 did not display the changing parameter values and overall model convergence correctly (at least for MODFLOW-2000).  Examination of the resulting text files indicated that the underlying routines were running properly.   

In summary, GMS 6.0 is a useful all around groundwater modeling package that offers the advantages of modular purchases, multiple model support, linkages to ArcGIS, conceptual model development, and integrated inversion routines. As with many software programs, new releases of GMS should be used cautiously with the understanding that some of the latest features may require revision before the full range of capabilities are functional.    

Rating System
5=Excellent, 4=Very Good, 3=Good, 2=Satisfactory, 1=Poor

Ease of Use

Groundwater Flow and Contaminant Transport

Best Feature

Link with ArcGIS and Conceptual Model Development

Worst Feature

Graphics Associated with Inversion Routines

Overall Rating