Online Guide to MODFLOW

Ftype—is the file type, which must be one of the following character values. Ftype may be entered in all uppercase, all lowercase, or any combination.

•GLOBAL for the global listing file—if this type is not present, the LIST file is used for the global listing file as well as for the forward run listing file. (MODFLOW-2000 only)

•LIST for the forward run listing file—if this type is not present, the GLOBAL file is used for the forward run listing file as well as for the global listing file.

The name file must always include a record that specifies GLOBAL or LIST for Ftype. Both records can be included, and if so, the GLOBAL record must be the first non-comment record and the LIST record must be the second non-comment record. If only one of the records is included, it must be the first non-comment record.

•DIS for the discretization file

•MULT for the multiplier array file

•ZONE for the zone array

•PVAL for the Parameter Value file (not included in MODFLOW-2000)

•BAS6 for the Groundwater Flow Process Basic Package

•OC for the Groundwater Flow Process Output Control Option

•BCF6 for the Groundwater Flow Process Block-Centered Flow Package

•LPF for the Groundwater Flow Process Layer Property Flow Package

•HUF2 for the Hydrogeologic Unit Flow Package

•UPW for the Upstream Weighting Package (MODFLOW-NWT only)

•HFB6 for the Groundwater Flow Process Horizontal Flow Barrier Package

•UZF for the Groundwater Flow Process Unsaturated-Zone Flow Package (not included in MODFLOW-2000)

•RCH for the Groundwater Flow Process Recharge Package

•RIV for the Groundwater Flow Process River Package

•WEL for the Groundwater Flow Process Well Package

•DRN for the Groundwater Flow Process Drain Package

•GHB for the Groundwater Flow Process General-Head Boundary Package

•EVT for the Groundwater Flow Process Evapotranspiration Package

•CHD for the Groundwater Flow Process Time-Variant Specified-Head Package

•SIP for the Strongly Implicit Procedure Package

•SOR for the Slice-Successive Over-Relaxation Package

•PCG for the Preconditioned Conjugate-Gradient Package

•DE4 for the Direct Solution Package

•IBS for the Interbed-Storage Package

•LMG for the Link-AMG Package

•NWT for the Newton Solver (MODFLOW-NWT only)

•LAK for the Lake Package

•GAGE for the Gage Package

•ETS for the Evapotranspiration Segments Package

•DRT for the Drain Return Package

•FHB for the Flow and Head Boundary Package

•HYD for the HYDMOD Package

•RES for the Reservoir Package

•MNW for the Multi-Node, Drawdown-Limited Well Package

•MNW2 for the Multi-Node Well Package version 2.

•MNWI for the Multi-Node Well Information Package

•DAF for the DAFLOW Package surface-water input file

•DAFG for the DAFLOW Package groundwater input file

•STR for the Stream Package

•SFR for the Streamflow-Routing Package

•KDEP for the Hydraulic-Conductivity Depth-Dependence Capability of the HUF2 Package

•LVDA for the Model-Layer Variable-Direction Horizontal Anisotropy capability of the HUF2 Package

•SUB for the Subsidence and Aquifer-System Compaction Package

•SWI2 for the Saltwater Intrusion Package

•LMT6 for the Link-MT3DMS Package

•OBS for the main Observation Process input file (MODFLOW-2000 only)

•ADV2 for the Advective-Transport Observation Input File (MODFLOW-2000 only)

•CHOB for the Constant-Head Flow Observation Input File

•DROB for the Drain Observation Input File

•DTOB for the Drain Return Observation Input File (MODFLOW-2000 only)

•GBOB for the General-Head-Boundary Observation Input File

•HOB for the Head-Observation Input File

•RVOB for the River Observation Input File

•STOB for the Streamflow-Routing Observation Input File (MODFLOW-2000 only)

•CFP for the Conduit Flow Process (MODFLOW-CFP only)

•CRCH for the Conduit Recharge Package (MODFLOW-CFP only)

•COC for the Conduit Output Control File (MODFLOW-CFP only)

•SEN for the Sensitivity Process input file (MODFLOW-2000 only)

•PES for the Parameter Estimation Process input file (MODFLOW-2000 only)

•FMP for the Farm Process (MODFLOW-OWHM only)

•RIP for the Riparian Evapotranspirtion package (MODFLOW-OWHM only)

•CFP for Conduit Flow Process (MODFLOW-CFP only)

•CRCH for Conduit Recharge (MODFLOW-CFP only)

•COC for Conduit Output Control (MODFLOW-CFP only)

•DATA(BINARY) for binary (unformatted) files, such as those used to save cell-by-cell budget data and binary (unformatted) head and drawdown data. Files of this type are rewound at the start of each parameter-estimation iteration.

•DATA for formatted (text) files, such as those used to save formatted head and drawdown and for input of data from files that are separate from the primary package input files. Files of this type are rewound at the start of each parameter-estimation iteration.

•DATAGLO(BINARY) for binary (unformatted) files, such as those used to save cell-by-cell budget data and binary (unformatted) head and drawdown data. Files of this type are not rewound at the start of each parameter-estimation iteration;. that is, output from each successive parameter iteration accumulates rather than overwriting information from the previous iteration.

•DATAGLO for formatted (text) files, such as those used to save formatted head and drawdown and for input of data from files that are separate from the primary package input files. Files of this type are not rewound at the start of each parameter-estimation iteration; that is, output from each successive parameter iteration accumulates rather than overwriting information from the previous iteration.

Nunit—is the Fortran unit to be used when reading from or writing to the file. Any legal unit number on the computer being used can be specified except units 96-99. Unit 99 is used for the name file and for reading multi-valued variables using the OPEN/CLOSE option of the utility modules (see Input Instructions for Array Reading Utility Modules section). Units 97 and 98 are used for batch files as explained in the ‘Running MODFLOW-2000’ section. (p. 42 of the documentation.) Unit 96 is used for a file to which error messages may be written when the Sensitivity Process is active. The Farm Process uses unit numbers 1001 through 1011 internally. The unit numbers used for pipe output by the Conduit Output Control File are numbered sequentially starting at 201 and the unit number used for output of the information about turbulent or laminer flow is 999. The unit number for each file must be unique.

Fname—is the name of the file, which is a character value. Pathnames may be specified as part of Fname. However, space characters are not allowed in Fname.

If Ftype is LIST, LSTLVL can be specified. LSTLVL allows suppression of some or all output to the listing file.

The options for output suppression are:

1 - Disable List File Output Completely

2 - Show Error Messages Only

3 - Show Error and Warning Messages

4 - Show Error, Warning, and Informational Messages (Show All)

LSTLVL is only included in MODFLOW-OWHM.

Option—New options for the name file allow users to designate files of type DATA, DATA(BINARY), DATAGLO, or DATAGLO(BINARY) as either input or output files.  One of the options (either "OLD" for an input file or "REPLACE" for an output file) may be placed after the file name on the line listing the file type, unit number, and file name.  If "OLD" is specified, the file must exist when the program is started.  If "REPLACE" is specified and the file exists when the program is started, the existing file is deleted, then opened.  The status of each file ("OLD", "REPLACE", or "UNKNOWN") is now shown in the global output file.  Note that the "OLD" or "REPLACE" option is not required.  If neither is listed, the file status is shown as "UNKNOWN" and program execution continues normally.  When output to a BINARY file from an earlier model run exceeds the amount of output generated by the current model run, specifying "REPLACE" may be required to ensure the file does not include output from the previous run after the output generated by the current run.  The options may be entered in any combination of uppercase and lowercase letters.

If a parallel version of MODFLOW-2000 is used, the REPLACE option should be used with output files.