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Online Guide to MODFLOW-LGR

Abbreviation in Name file

WEL

Purpose

The Well package is used to simulate a specified flux to individual cells and specified in units of length3/time.

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://doi.org/10.3133/tm6A16

Time-varying-parameters.pdf

release.txt

modpath.txt

Niswonger, R.G., Panday, Sorab, and Ibaraki, Motomu, 2011, MODFLOW-NWT, A Newton formulation for MODFLOW-2005: U.S. Geological Survey Techniques and Methods 6-A37, 44 p.

release.txt for MODFLOW-NWT

Related Packages

The Recharge package is used to simulate a specified flux distributed over the top of the model and specified in units of length/time.  Within MODFLOW, these rates are multiplied by the horizontal area of the cells to which they are applied to calculate the volumetric flux rates.

The Flow and Head Boundary package can be used to simulate a specified flux to particular cells specified in units of length3/time and varying as a function of time within stress periods.

Supported in

MODFLOW-2000

MODFLOW-2005

MODFLOW-LGR

MODFLOW-CFP

MODFLOW-NWT

MODFLOW-OWHM

Other Notes

Input Instructions

Input to the Well (WEL) Package is read from the file that has type "WEL" in the name file. Optional variables are shown in brackets. All variables are free format if the option “FREE” is specified in the Basic Package input file; otherwise, the non-optional variables have 10-character fields and the optional variables are free format.

FOR EACH SIMULATION

Data Set 0

[#Text]

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

Data Set 1

[ PARAMETER NPWEL MXL]

This optional item must start with the word “PARAMETER”.

 


 


 


 


 

 

Data Set 2a

MXACTW IWELCB [Option]

Data Set 2b

Data set 2b can only be specified in versions of MODFLOW that include the NWT solver. PHIRAMP is only used if NWT is the selected solver. Otherwise, it is ignored.

[SPECIFY PHIRAMP IUNITRAMP]

Repeat Items 3 and 4 for each NPWEL parameter.

Data Set 3

[PARNAM PARTYP Parval NLST [INSTANCES NUMINST]]

If PARNAM is to be a time-varying parameter, the keyword “INSTANCES” and a value for NUMINST must be entered.

Data Set 4a

INSTNAM

Item 4a is read only if PARNAM is time-varying. NUMINST repetitions of Item 4 (parts a and b) are read. After each repetition of Item 4a, NLST repetitions of Item 4b are read.

Data Set 4b

Layer Row Column Qfact [xyz]

NLST repetitions of Item 4b are required; they are read by module ULSTRD. (SFAC of the ULSTRD utility module applies to Qfact).  The NLST repetitions of Item 4b follow each repetition of Item 4a when PARNAM is time-varying.

FOR EACH STRESS PERIOD

Data Set 5

ITMP NP

 


Data Set 6

Layer Row Column Q [xyz]

ITMP repetitions of Item 6 are read by module ULSTRD if ITMP > 0. (SFAC of the ULSTRD utility module applies to Q.) Item 6 is not read if ITMP is negative or zero.

Data Set 7

[Pname [Iname]]

Item 7 is repeated NP times. It is not read if NP is negative or 0.  Iname is read if Pname is a time-varying parameter.

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