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Model Info
Model type 3D Transport Model
Developer -

Old MT3DMS Manual

Current MT3DMS v5.3 Supplemental Manual
Tutorials MT3DMS Tutorials

MT3DMS (Modular Transport, 3-Dimensional, Multi-Species model) is a modular three-dimensional transport model for the simulation of advection, dispersion, and chemical reactions of dissolved constituents in groundwater systems (Zheng, 1990). MT3DMS uses a modular structure similar to the structure utilized by MODFLOW. MT3DMS is used in conjunction with MODFLOW in a two step flow and transport simulation. Heads and cell-by-cell flux terms are computed by MODFLOW during the flow simulation and are written to a specially formatted HFF file (referenced by the LMT file). Note: MODFLOW will produce these files even if transport is turned off. These files are then read by MT3DMS and utilized as the flow field for the transport portion of the simulation.


MT3DMS is a newer version of the old MT3D model that was distributed with earlier versions of GMS. GMS 8.0 and later now run MT3DMS version 5.3 (built in Feb 2010). MT3DMS differs from MT3D in that it allows for multi-species transport, supports additional solvers, and allows for cell-by-cell input of all model parameters.

The RT3D, SEAM3D and PHT3D models are special versions of MT3DMS that have been customized to simulate reactive transport problems. The interfaces to MT3DMS, RT3D, SEAM3D and PHT3D are all contained in the MT3DMS menu. MT3D-USGS is another version of MT3D released in 2016 that includes the functionality of MT3DMS plus additional capabilities and packages.

A complete description of MT3DMS is beyond the scope of this reference manual. It is assumed that the reader has a basic knowledge of MT3DMS and is familiar with the MT3DMS original and supplementary documentation (Zheng, 1990). Only the details of the GMS graphical interface to MT3DMS are described in these pages.


A special version of MT3DMS is distributed with GMS, and the model is included with all paid editions of GMS.

This version of MT3DMS has been modified to output GMS dataset files. GMS supports MT3DMS as a pre- and post-processor where the input data for MT3DMS is generated by GMS and saved to a set of files. These files are then read by MT3DMS when MT3DMS is executed from the GMS menu. The output super file (*.mts) generated from MT3DMS is then imported to GMS for post-processing and viewing.

MT3DMS Run Options

MT3DMS requires using solution files generated from a MODFLOW model run. An option is provided to use MODFLOW solution files completed from previous model runs using the Run Options dialog.

The Run Options dialog

Supported MODFLOW Packages

MT3DMS v5.3 supports the following MODFLOW packages that are also supported in GMS: BAS6, BCF, LPF, HUF, HFB, CHD, WEL, DRN, RIV, GHB, RCH, EVT, STR, and LAK.

MT3DMS Files

Here are tables of some of the available input and output files for MT3DMS.

Input Files
Name Description
MTS MT3DMS Super File
BTN Basic Transport Package File
ADV Advection Package File
DSP Dispersion Package File
SSM Sink and Source Mixing Package File
RCT Chemical Reactions Package File
GCG Generalized Conjugate Gradient Solver Package File
TOB Transport Observation Package File
PHC PHT3D-PHREEQC Interface Package File
HSS Hydrocarbon Spill Source Time-Varying Package File
Output Files
Name Description
OUT Model Output Text File
CNF Model Spatial Discretization Configuration File
UCN Unformatted Concentration (Dissolved Phase) File
UCN Unformatted Concentration (Sorbed/Immobile Phase) File
OBS Concentration Observation File
MAS Mass Budget Summary File
OCN Output Concentration File
MTR Unformatted Concentration (Sorbed/Immobile Phase) File
PST Binary Post-Processing File
MAS Mass Budget Summary File

MT3DMS Links

See also