1. General Model Information

Name: moc3d - Three-dimensional method-of-characteristics ground-water

Acronym: MOC3D

Contact:

Author(s):

Abstract:

New 3D-version of the widespread USGS-MOC model.

This model simulates three-dimensional solute transport in flowing ground water. The model computes changes in concentration of a single dissolved chemical constituent over time that are caused by advective transport, hydrodynamic dispersion (including both mech- anical dispersion and diffusion), mixing (or dilution) from fluid sources, and mathematically simple chemical reactions (including linear sorption, which is represented by a retardation factor, and decay).

METHOD

The transport model is integrated with MODFLOW, a three-dimensional ground-water flow model that uses implicit finite-difference methods to solve the transient flow equation. MOC3D uses the method-of- characteristics to solve the transport equation on the basis of the hydraulic gradients computed with MODFLOW for a given time step. Particle tracking is used to represent advective transport and explicit finite-difference methods are used to calculate the effects of other processes.

HISTORY

Version: 1.0 1996/11/08 - Initial release

DATA REQUIREMENTS:

Initial conditions, boundary conditions, aquifer properties at every node, and grid descriptors.

II. Technical Information

II.1 Executables:

II.2 Source-code:

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

The basic MODFLOW documentation is contained in the following three reports:

McDonald, M.G., and Harbaugh, A.W., 1988, A modular three- imensional finite-difference ground-water flow model: U.S. Geological Survey Techniques of Water-Resources Investigations, book 6, chap. A1, 586 p.
Harbaugh, A.W., and McDonald, M.G., 1996, User's documentation for MODFLOW-96, and update to the U.S. Geological Survey modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 96-485, 56 p.
Harbaugh, A.W., and McDonald, M.G., 1996, Programmer's documentation for MODFLOW-96, and update to the U.S. Geological Survey modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 96-486, 220 p.

RELATED DOCUMENTATION:

Konikow, L.F., Granato, G.E., and Hornberger, G.Z., 1994, User's guide to revised method-of-characteristics solute-transport model (MOC--Version 3.1): U.S. Geological Survey Water-Resources Investigations Report 94-4115.
Goode, D.J., and Konikow, L.F., 1989 , Modification of a method-of- characteristics solute-transport model to incorporate decay and equilibrium-controlled sorption or ion exchange: U.S. Geological Survey Water-Resources Investigations Report 89-4030, 65 p.
Konikow, L.F., and Bredehoeft, J.D., 1978, Computer model of two- dimensional solute transport and dispersion in ground water: U.S. Geological Survey Techniques of Water-Resources Investigations, book 7, chap. C2, 90 p.

V. Further information in the World-Wide-Web