UNIT 14 -- MT3D INPUT AND EXECUTION:

Now we move on to implementing MT3D for a contaminant transport simulation.

In this unit we will add contaminant transport aspects to our modeling exercise.

We will use MT3D for contaminant transport simulation in this class

The OBJECTIVE of UNIT 14 is for you to:

* BECOME FAMILIAR with OPTIONS and FEATURES AVAILABLE in MT3D

* Be ABLE to CREATE MT3D INPUT and SUCCESSFULLY EXECUTE MT3D

DISCUSSION
MT3D is a 3D transport model which uses the flow field calculated by a block centered finite difference code (most commonly MODFLOW) to simulate advection, dispersion and chemical reactions. The version of MODFLOW you use must have the appropriate section of code to create the input file for MT3D. For our transport work we will use GMS. The GMS version of MODFLOW can create MT3D input files. MODFLOW2000 added the USGS MOC3D code, but as yet the GUI developers have not included MOC3D. If you find yourself with a version of MODFLOW that does not produce MT3D input files, you can visit Dr. Zheng's web page to obtain the code modification and directions on how to add it.

MT3D was written primarily by Chunmiao Zheng, initially while at S.S. Papadopulos & Associates and later at the University of Alabama. It is public domain and you can learn more about it at Dr. Zheng's web site Get the most recent release of the code, documentation and associated reports at that site under MT3D resources.

The MT3D code offers a number of solution options, including the method of characteristics (MOC), the modified method of characteristics (MMOC), a hybrid of these two methods (HMOC), and the standard finite-difference method (FDM). Later versions incorporated a powerful Total Variational Diminishing Method (TVD) scheme , a higher order finite difference method that conserves mass and suppresses artificial oscillations.

The latest version of MT3D is called MT3DMS to indicate that it can simulate multiple species. It simulates equilibrium-controlled or rate-limited linear or non-linear sorption, and first-order irreversible or reversible kinetic reactions.

MT3D INPUT and EXECUTION

EXERCISES

If you chose to purchase Applied Contaminant Transport Modeling,
Visit the places where MT3D is mentioned in the index: pp. 82, 140, 149, 167, 185, 196-198, 213, 217, 222, 228-229, 302, 308, 366, 378
Read about MT3D in the MT3D manual which can be down loaded from the document sharing area.

Read the material at Dr. Zheng's web site where you can download the latest code and manual.