Appendix A - Input files and Packages

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Appendix A - Input and Output Files

When you "Translate" in the numerical model, a number of text files will be created; these input files (called packages) are required for the numerical models (engines) to run.  These files are saved in the "Run" directory for the current grid/run that you have selected, in the data repository; for example:



If you choose a different engine (at the "Select Engines" step), then a new folder will be created under that run.

In Visual MODFLOW Flex, most of the packages containing arrays will have a main "index" file which lists global settings/parameters and provides file references to the other files that are also inputs for that package. An example is the MODFLOW .DIS package; some general parameters (such as units) and temporal discretization (number of stress periods and time steps) are described in this projectname.DIS file; however, cell elevations for each layer are described in their own separate file, for example Projectname.DIS.Bot1 (contains bottom elevations for each cell, for layer 1)

A brief description of these files is listed below, where projectname is the name assigned to the model.

MODFLOW (2000, 2005, NWT)

A brief description of these files is listed below, where projectname is the name assigned to the model.


Input files:

projectname.modflow.IN List of translated files for MODFLOW

projectname.BAS: Basic Package data file

projectname.BCF: Block-Centered Flow Package data file.

projectname.CHD: Time-variant specified head data file

projectname.DIS: Model discretization data file

projectname.DRN:  Drain Package data file

projectname.EVT: Evapotranspiration Package data file (MODFLOW-2000).

projectname.EVP: Evapotranspiration Package data file (MODFLOW-96).

projectname.GHB: General-Head Boundary Package data file

projectname.HFB: Horizontal Flow Boundary Package data file.

projectname.LPF: Layer Property Flow data file

projectname.OC: Output control options data file

projectname.PCG: PCG2 Solver Package data file

projectname.RCH: Recharge Package data file

projectname.RIV: River Package data file

projectname.SIP: SIP Solver Package data file

projectname.SOR: SOR Solver Package data file

projectname.UZF: Unsaturated Zone Flow Package date file

projectname.WEL Well Package data file

projectname.WHS: WHS Solver data file


Packages specific to MODFLOW-NWT:

projectname.UPW: Upstream Weighting (property package, only when MODFLOW-NWT is selected)

projectname.NWT: NWT Solver settings (this solver must be used when MODFLOW-NWT is selected)



Output files:

projectname.BGT* MODFLOW file containing water budget data used by MODPATH (Binary format)

projectname.CBB* MODFLOW-SURFACT file containing water budget data used by MODPATH (Binary format)

projectname.DDN MODFLOW file containing drawdown X, Y, Z heads for each node (Binary format)

projectname.FLO* MODFLOW file containing cell-by-cell flow terms (Binary format)

projectname.HDS* MODFLOW file containing head results (Binary format)

projectname.LST* MODFLOW listing file containing information and messages from MODFLOW (ASCII format)




Input files:

BACKWARD.IN Backward tracking particle locations data file

BACKWARD.PTH Backward tracking run options data file

FORWARD.IN Forward tracking particle locations data file

FORWARD.PTH Forward tracking run options data file

projectname.MPT Main MODPATH input data file

MODPATH.IN List of MODPATH input files


Output files:

projectname.CBF Composite Budget file used by MODPATH

projectname.MPB MODPATH file containing backward tracking particle information (ASCII format)

projectname.MPF MODPATH file containing forward particle information (ASCII format)

SUMMARY.PTH* MODPATH file containing listing information and messages from MODPATH (ASCII format)




Input files:

projectname.AD3 Advection data file

projectname.BT3 Basic Transport data file

projectname.DP3 Dispersion data file

projectname.GCG Transport Solver data file

projectname.RC3 Chemical Reaction data file

projectname.SS3 Source / Sink Mixing data file

RT3D.IN List of RT3D input files


Packages specific to MT3DMS:

MT3D.IN List of MT3D input files


Packages specific to RT3D:

RT3D.IN List of RT3D input files


Packages specific to SEAWAT:

SEAWAT.IN List of SEAWAT input files

projectname.VDF Variable Density Flow data file

projectname.VSC Viscosity data file


Output files:

projectname.CNF* MT3D file containing model grid configuration file (ASCII format)

projectname.MAS* MT3D file containing mass balance file (ASCII format)

NOTE: The mass balance files are displayed by MS-Windows as projectname.001, projectname.002, etc.

projectname.OBS* MT3D file containing concentration at observation points (ASCII format). The data is presented with units of mass/length^3

projectname.OT* MT3D output file containing listing information and messages from MT3D e.g. cumulative mass budget data (ASCII format)

projectname.UCN* MT3D file containing unformatted concentration information - (Binary format)

projectname.CBM/CCM* MT3D96/MT3D99 cell-by-cell mass terms (Binary format)




Input files:

projectname.ZBI Zone Budget data file

ZONEBUD.IN List of Zone Budget input files


Output files:

projectname.ZOT Zone Budget file containing water balance data (ASCII format).


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