U.S. Geological Survey
Water Resources Applications Software

Geochemical || Ground Water || Surface Water || Water Quality || General

Summary of MOC3D

       moc3d - Three-dimensional method-of-characteristics ground-water
               flow and transport 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
       mechanical 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).  The model can also simulate ground-water
       age transport and the effects of double porosity and zero-order

       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.

       Version 3.52 2004/01 - Fix minor bugs in source

       Version 3.51 2001/10 - Updated simulation progress report to screen 

       Version 3.5 2000/07 - Added ELLAM algorithm, bug fix for thickness 
          calculation in transient runs, bug fix for package flags

       Version 3.0 1999/03/24 - Added capabilities to simulate age transport,
          double porosity exchange, and simple reactions.  The simple
          reactions include cell-by-cell terms for decay and zero-order
          growth/loss.  Decay and growth coefficients can change in time
          at the beginning of each flow model stress period.

       Version 2.02 1999/03/08 - Added the elapsed transport time to the
          header information for particle output files.

       Version 2.01 1999/01/25 - Altered the replacement scheme for
          particles entering the subgrid to fix distribution problems for
          weakly divergent flow fields near subgrid boundaries.

       Version 2.0 1998/11/16 - Added implicit dispersive transport
          algorithm, rearranged main.f file to call a MOC3D control module
          (moc_main.f), added new output option for printing concentrations
          in "table" style, FHB package added, added printing of time step
          and stress period in MOC3D output file, fixed velocity
          calculation bug (KSTP>1, ISS=0), corrected calculation of subgrid
          face counter, fixed bug in mass balance calculation for decay,
          fixed sign in saturated thickness calculation, corrected check
          for porosity vs. storage terms, typographical errors fixed.

       Version 1.2 1998/05/01 - Output control for particles (NPNTPL)
          fixed; automatic initialization for retardation factor (RF) fixed,
          bug in crch5.f fixed, single header line for CNCA and VELA files,
          test for rounding error in move.f fixed, HFB1 and DE45 packages
          added, mass balance loop error fixed, some output formats changed.

       Version 1.1 1997/05/14 - Minor bug fixes affecting a format
          statement and output of initial condition data to observation
          well file.

       Version 1.0 1996/11/08 - Initial release

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

       See documentation.

       MOC3D is written in Fortran 77 with the following extension:  use of
       variable names longer than 6 characters.  By default, the software
       is dimensioned for use with models having up to 20,000 cells and
       200,000 particles.  MOC3D requires that file names required for the
       simulation be defined prior to execution.  Two Name Files (MODFLOW
       and MOC3D) must be used for this purpose.  The format of these are
       described in the documentation.  Generally, the program is easily
       installed on most computer systems.  The code has been used on UNIX-
       based computers and DOS-based 386 or greater computers having a math
       coprocessor and 8 mb of memory.

       Goode, D.J., 1999, Age, double porosity, and simple reaction
          modifications for the MOC3D ground-water transport model: 
          U.S. Geological Survey Water-Resources Investigations 
          Report 99-4041, 34 p.
       Heberton, C.I., Russel, T.F., Konikow, L.F., Hornberger, 
          G.Z., 2000, A Three-Dimensional Finite Volume Eulerian-
          Lagrangian Localized Adjoint Method (ELLAM) for Solute-
          Transport Modeling: U.S. Geological Survey Water-Resources 
          Investigations Report 00-4087, 63 p.

       Kipp, K.L., L.F. Konikow, and G.Z. Hornberger, 1998, An Implicit
          Dispersive Transport Algorithm for the U.S. Geological Survey
          MOC3D Solute-Transport Model: U.S. Geological Survey Water-
          Resources Investigations Report 98-4234, 54 p.

       Konikow, L.F., Goode, D.J., and Hornberger, G.Z., 1996, A Three-
          Dimensional Method-of-Characteristics Solute-Transport Model
          (MOC3D): U.S. Geological Survey Water-Resources Investigations
          Report 96-4267, 87 p.

       The basic MODFLOW documentation is contained in the following three

       McDonald, M.G., and Harbaugh, A.W., 1988, A modular three-
          dimensional 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.

       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.

       Modeling Transport of Ground-Water Solutes (GW2080TC), offered
       annually at the USGS National Training Center.

       Operation and Distribution:
          U.S. Geological Survey
          Hydrologic Analysis Software Support Team
          437 National Center
          Reston, VA 20192


       Official versions of U.S. Geological Survey water-resources analysis
       software are available for electronic retrieval via the World Wide
       Web (WWW) at:


       and via anonymous File Transfer Protocol (FTP) from:

                  water.usgs.gov (path: /pub/software).

       The WWW page and anonymous FTP directory from which the MOC3D
       software can be retrieved are, respectively:


       If you would like to obtain the price of and (or) order paper copies
       of USGS reports, contact the USGS Branch of Information Services at:

                  U.S. Geological Survey
                  Branch of Information Services
                  Denver Federal Center, Box 25286
                  Denver CO 80225-0286

       To inquire about Open-File Reports or Water-Resources Investigations
                  Tel: 303-202-4210; Fax 303-202-4695

       To inquire about other USGS reports:
                  Tel: 303-202-4700; Fax 303-202-4693


       mf2k_gwt - Ground-Water Transport process integrated with MODFLOW-2000
       mfi - A preprocessor for MODFLOW
       moc - Two-dimensional method-of-characteristics ground-water
                flow and transport model
       modflw96 - Modular three-dimensional finite-difference
                     ground-water flow model
       Modflowp - Parameter-estimation version of the modular model
       sutra - Saturated and (or) unsaturated, constant or
                  variable-density fluid flow, and solute or energy
                  transport (2-dimensional finite-element code)
       vs2dt - Model for simulating water flow and solute
                  transport in variably saturated porous media
       modflow-gui - graphical user interface for MODFLOW-96 and MOC3D

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Web page comments, contact: George Z. Hornberger <gzhornbe@usgs.gov>
U.S. Geological Survey
431 National Center
Reston, VA 20192

Last Iteration: Jan 15 2004