Online Guide to MODFLOW-2000

MULT - Multiplier File

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MULT - Multiplier File

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Abbreviation in Name file



The Multiplier File  is used to specify multiplier arrays which can be used to calculate layer variables from parameter values.


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.

Supported in


Other Notes

Multiplier arrays are used in the ADV2, ETS, EVT, HUF2, KDEP, LPF, LVDA, RCH, and UPW (MODFLOW-NWT) input files.

Input Instructions

Input to define multiplier arrays is read from the file that is specified with "MULT" as the file type. Multiplier arrays can be used to calculate layer variables from parameter values.


Data Set 0


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


NML—is the number of multiplier arrays to be defined.  In MODFLOW-2000, the maximum number of multiplier arrays is 1000.


Repeat Item 2 with Items 3 or 4 until NML multiplier arrays, vectors, or scalars have been defined.

Data Set 2


MLTNAM—is the name of a multiplier array. This name can consist of 1 to 10 characters and is not case sensitive. That is, any combination of the same characters with different case are equivalent. The name “NONE” should not be used for a multiplier array because it is a reserved word.

The optional keyword, FUNCTION, indicates that the multiplier array will be constructed from other multiplier arrays that have already been defined. Construction is by arithmetic combinations of the multipliers; see the explanation below for variable op1, op2, op3 ....


Data Set 3


If Item 2 does not contain the optional FUNCTION key word, read item 3.

RMLT—is a multiplier array.

Data Set 4

[MLTNAM1 [op1 MLTNAM2] [op2 MLTNAM3] [op3 MLTNAM4] ... ] [IPRN]

Item 4 is only read if Item 3 contains the optional FUNCTION key word.

MLTNAM1, MLTNAM2, MLTNAM3, ...—are the names of multiplier arrays that have already been defined. op1, op2, op3, ...—are arithmetic operators used to define a multiplier array based on other multiplier arrays. Each operator can be either “+”, “-”, “*”, or “/”. Operations are applied from left to right to each array element. The operators must be separated from the multiplier array names by at least one space.

IPRN is a flag that indicates if the array defined in Item 4 should be printed (written to the listing file) after it has been generated and a code for indicating the format that should be used when it is printed.

If IPRN < 0, printing of the multiplier array is suppressed.