OC - Output Control Option

Abbreviation in Name file

Purpose

The Output Control Option is used to specify which head, drawdown, or budget data should be printed or saved.

Documentation

•	Harbaugh, A.W., Banta, E.R., Hill, M.C., and McDonald, M.G., 2000, MODFLOW-2000, the U.S. Geological Survey modular ground-water model -- User guide to modularization concepts and the Ground-Water Flow Process: U.S. Geological Survey Open-File Report 00-92, 121 p.

•	Harbaugh, A.W., 2005, MODFLOW-2005, the U.S. Geological Survey modular ground-water model -- the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16. https://pubs.usgs.gov/tm/2005/tm6A16/

•	release.txt

•	ofr-00-92-errata.pdf

•	modpath.txt

•	Hanson, R.T., Boyce, S.E., Schmid, Wolfgang, Hughes, J.D., Mehl, S.M., Leake, S.A., Maddock, Thomas, III, and Niswonger, R.G., 2014, One-Water Hydrologic Flow Model (MODFLOW-OWHM): U.S. Geological Survey Techniques and Methods 6–A51, 120 p., https://dx.doi.org/10.3133/tm6A51.

Related Packages

HYDMOD Package

Supported in

•	MODFLOW-2000

•	MODFLOW-2005

•	MODFLOW-LGR

•	MODFLOW-CFP

•	MODFLOW-NWT

•	MODFLOW-OWHM

Other Notes

The Output Control Option is optional.

See the Frequently Asked Questions for information on how to read data from binary files generated by MODFLOW.

Input Instructions

Input to the Output Control Option of the Groundwater Flow Process is read from the file that is specified as type "OC" in the name file. If no "OC" file is specified, default output control is used. Under the default, head and overall budget are written to the listing file (printed) at the end of every stress period. The default printout format for head and drawdown is 10G11.4.

There are two ways to specify Output Control data: words or numeric codes. One of these methods must be used throughout any simulation.

Recognized words are shown in bold italics; these words must be entered exactly as shown except that they may be entered in either uppercase or lowercase. Optional parts of records are shown in brackets. One or more spaces must separate each word or variable, and the total record length must not exceed 199 characters.

FOR EACH SIMULATION

Data Set 0

[#Text]

Item 0 is optional—“#” must be in column 1. Item 0 can be repeated multiple times.

# Text—is a character variable (199 characters) that starts in column 2. Any characters can be included in Text. The “#” character must be in column 1. Except for the name file, lines beginning with # are restricted to these first lines of the file. Text is printed when the file is read.

Data Set 1

Any combination of the following records:

•	HEAD PRINT FORMAT IHEDFM

IHEDFM—is a code for the format in which heads will be printed. (Positive values for wrap format; negative values for strip format.)

IHEDFM	FORMAT
0	10G11.4
1	11G10.3
2	9G13.6
3	15F7.1
4	15F7.2
5	15F7.3
6	15F7.4
7	20F5.0
8	20F5.1
9	20F5.2
10	20F5.3
11	20F5.4
12	10G11.4
13	10F6.0
14	10F6.1
15	10F6.2
16	10F6.3
17	10F6.4
18	10F6.5
19	5G12.5
20	6G11.4
21	7G9.2

•	HEAD SAVE FORMAT CHEDFM [ LABEL] Omit to obtain an unformatted file.

CHEDFM—is a character value that specifies the format for saving heads, and can only be specified if the word method of output control is used. The format must contain 20 characters or less and must be a valid Fortran format that is enclosed in parentheses. The format must be enclosed in apostrophes if it contains one or more blanks or commas. The optional word LABEL after the format is used to indicate that each layer of output should be preceded with a line that defines the output (simulation time, the layer being output, and so forth). If there is no record specifying CHEDFM, then heads are written to a binary (unformatted) file. Binary files are usually more compact than text files, but they are not generally transportable among different computer operating systems or different Fortran compilers.

•	HEAD SAVE UNIT IHEDUN

IHEDUN—is the unit number on which heads will be saved.

•	DRAWDOWN PRINT FORMAT IDDNFM

IDDNFM—is a code for the format in which drawdowns will be printed. The codes are the same as for IHEDFM.

•	DRAWDOWN SAVE FORMAT CDDNFM [ LABEL] Omit to obtain an unformatted file.

CDDNFM—is a character value that specifies the format for saving drawdown, and can only be specified if the word method of output control is used. The format must contain 20 characters or less and must be a valid Fortran format that is enclosed in parentheses. The format must be enclosed in apostrophes if it contains one or more blanks or commas. The optional word LABEL after the format is used to indicate that each layer of output should be preceded with a line that defines the output (simulation time, the layer being output, and so forth). If there is no record specifying CDDNFM, then drawdown is written to a binary (unformatted) file. Binary files are usually more compact than text files, but they are not generally transportable among different computer operating systems or different Fortran compilers.

•	DRAWDOWN SAVE UNIT IDDNUN

IDDNUN—is the unit number on which drawdowns will be saved.

•	IBOUND SAVE FORMAT CBOUFM [ LABEL]

CBOUFM—is a character value that specifies the format for saving IBOUND, and can only be specified if the word method of output control is used. The format must contain 20 characters or less and must be a valid Fortran format that is enclosed in parentheses. The format must be enclosed in apostrophes if it contains one or more blanks or commas. The optional word LABEL is used to indicate that each layer of output should be preceded with a line that defines the output (simulation time, the layer being output, and so forth). If there is no record specifying CBOUFM, then IBOUND is written using format (20I4). IBOUND is never written as a binary (unformatted) file.

•	IBOUND SAVE UNIT IBOUUN

IBOUUN—is the unit number on which the IBOUND array will be saved.

•	COMPACT BUDGET [ AUX or AUXILIARY]

If the final “COMPACT BUDGET” option is used, cell-by-cell budget files produced require less disk space than files written by MODFLOW-88; however, programs that read these data using the specifications of MODFLOW-88 will need to be modified. If this option is not used, MODFLOW-2000 will write the files using the MODFLOW-88 method. The optional word “AUX” (or “AUXILIARY”) after “COMPACT BUDGET” indicates that auxiliary data that are defined in packages (see input data for the RIV, WEL, DRN, and GHB Packages) should be saved in the budget file along with budget data. When using MODPATH, the COMPACT BUDGET option with AUX is required.

If the “COMPACT BUDGET” option is used, the time step size, the elapsed time in the current stress period and the total elapsed time will be saved in the budget file.

•	WBGT SAVE UNIT UnitNumber

UnitNumber is the unit number of a file to which the groundwater summary budgets will be written. The unit number should be included in the name with with the FTYPE DATA. This option is only included in MODFLOW-OWHM.

PRINT indicates that the model output is written to the LIST file.

SAVE indicates that output is written to the indicated file unit. Drawdown and head are saved as text files if the SAVE FORMAT record is included. If the SAVE FORMAT record is not used, then the file is written as a binary (unformatted) file. Binary files are usually more compact than text files, but they are not generally transportable among different computer operating systems or different Fortran compilers.

FOR EACH TIME STEP FOR WHICH OUTPUT IS DESIRED

Data Set 2

PERIOD IPEROC STEP ITSOC [DDREFERENCE]

IPEROC—is the stress period number at which output is desired.

ITSOC—is the time step number (within a stress period) at which output is desired.

DDREFERENCE—indicates that the heads calculated at the associated stress period and time step are to be used as the reference heads for calculating drawdown for all subsequent time steps up to the next occurrence of DDREFERENCE. Prior to the first occurrence (if any) of DDREFERENCE the initial heads will be used as the reference heads for calculating drawdown.

Data Set 3

Any combination of the following records:

PRINT HEAD [list layers if all layers not desired]

PRINT DRAWDOWN [list layers if all layers not desired]

PRINT BUDGET Write overall volumetric budget to the LIST file.

SAVE HEAD [list layers if all layers not desired]

SAVE DRAWDOWN [list layers if all layers not desired]

SAVE IBOUND [list layers if all layers not desired]

SAVE BUDGET Write cell-by-cell budget data to a file.

SAVE WBGT Write the groundwater summary budget to a file. This option is only included in MODFLOW-OWHM.

Item 2 and one or more item-3 records are specified for each time for which output is desired. These records must be in the order of increasing simulation time.

Example Output Control Input Using Words

The first line cannot be blank, but after the first line blank lines are ignored when the word method is used to specify Output Control data. Indented lines are allowed because of the use of free format input.

HEAD PRINT FORMAT 15

HEAD SAVE FORMAT (20F10.3) LABEL

HEAD SAVE UNIT 30

COMPACT BUDGET FILES

DRAWDOWN PRINT FORMAT 14

PERIOD 1 STEP 1

PRINT HEAD 2 6

PRINT DRAWDOWN

PRINT BUDGET

SAVE BUDGET

SAVE HEAD

PERIOD 1 STEP 7

SAVE HEAD 1 3 5

PRINT DRAWDOWN

SAVE BUDGET

PERIOD 2 STEP 5

PRINT HEAD

PRINT BUDGET

SAVE BUDGET

SAVE HEAD

All variables are free format if the word FREE is specified in Item 1 of the Basic Package input file; otherwise, the variables all have 10-character fields.

FOR EACH SIMULATION

Data Set 0

[#Text]

Item 0 is optional—“#” must be in column 1. Item 0 can be repeated multiple times.

Text—is a character variable (199 characters) that starts in column 2. Any characters can be included in Text. The “#” character must be in column 1. Except for the name file, lines beginning with # are restricted to these first lines of the file. Text is printed when the file is read.

Data Set 1

IHEDFM IDDNFM IHEDUN IDDNUN

IHEDFM—is a code for the format in which heads will be printed. (Positive values for wrap format; negative values for strip format.)

IHEDFM	FORMAT
0	10G11.4
1	11G10.3
2	9G13.6
3	15F7.1
4	15F7.2
5	15F7.3
6	15F7.4
7	20F5.0
8	20F5.1
9	20F5.2
10	20F5.3
11	20F5.4
12	10G11.4
13	10F6.0
14	10F6.1
15	10F6.2
16	10F6.3
17	10F6.4
18	10F6.5
19	5G12.5
20	6G11.4
21	7G9.2

IDDNFM—is a code for the format in which drawdowns will be printed. The codes are the same as for IHEDFM.

IHEDUN—is the unit number on which heads will be saved.

IDDNUN—is the unit number on which drawdowns will be saved.

FOR EACH TIME STEP

Data Set 2

INCODE IHDDFL IBUDFL ICBCFL

INCODE—is the code for reading Item 3.

•	If INCODE < 0, Item 3 flags are used from the last time step. Item 3 is not read.

•	If INCODE = 0, all layers are treated the same way. Item 3 will consist of one record.

•	If INCODE > 0, Item 3 will consist of one record for each layer.

IHDDFL—is a head and drawdown output flag. This flag allows Item 3 flags to be specified in an early time step and then used or not used in subsequent time steps. Thus, it may be possible to use IHDDFL to avoid resetting Item 3 flags every time step.

•	If IHDDFL = 0, no heads or drawdowns will be printed or saved regardless of which Item 3 flags are specified.

•	If IHDDFL ≠ 0, heads and drawdowns will be printed or saved according to the Item 3 flags.

IBUDFL—is a budget print flag.

•	If IBUDFL = 0, overall volumetric budget will not be printed.

•	If IBUDFL ≠ 0, overall volumetric budget will be printed.

ICBCFL—is a flag for writing cell-by-cell flow data.

•	If ICBCFL = 0, cell-by-cell flow terms are not written to any file.

•	If ICBCFL ≠ 0, cell-by-cell flow terms are written to the LIST file or a budget file depending on flags set in the component of flow packages, that is, IWELCB, IRCHCB, and so forth. This is equivalent to SAVE BUDGET

Data Set 3

Hdpr Ddpr Hdsv Ddsv

(Item 3 is read 0, 1, or NLAY times, depending on the value of INCODE.)

Hdpr—is the output flag for head printout.

•	If Hdpr = 0, head is not printed for the corresponding layer.

•	If Hdpr ≠ 0, head is printed for the corresponding layer.

Ddpr—is the output flag for drawdown printout.

•	If Ddpr = 0, drawdown is not printed for the corresponding layer.

•	If Ddpr ≠ 0, drawdown is printed for the corresponding layer.

Hdsv—is the output flag for head save.

•	If Hdsv = 0, head is not saved for the corresponding layer.

•	If Hdsv ≠ 0, head is saved for the corresponding layer.

Ddsv—is the output flag for drawdown save.

•	If Ddsv = 0, drawdown is not saved for the corresponding layer.

•	If Ddsv ≠ 0, drawdown is saved for the corresponding layer.

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