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Online Guide to MODFLOW-2000

Abbreviation in Name file

MNW2

Purpose

The Multi-Node Well packag is used to simulate “long” wells that are connected to more than one node of the finite-difference grid. The software represents a revision to a previously published Multi-Node Well Package and is meant to replace the previous version. The modifications allow corrections for the effects of partially penetrating wells, improved treatment of non-vertical wells, and adjustments in discharge according to specified pump performance (head-capacity) curves, among other changes.

Documentation

Konikow, L.F., Hornberger, G.Z., Halford, K.J., and Hanson, R.T., 2009, Revised multi-node well (MNW2) package for MODFLOW ground-water flow model: U.S. Geological Survey Techniques and Methods 6–A30, 67 p.

Release.txt for MODFLOW-NWT

readme_MNW2.txt

Related Packages

Well package

MNW1 package

MNWI package

Head-Dependent Flux Boundary packages

Supported in

MODFLOW-2000

MODFLOW-2005

MODFLOW-LGR

MODFLOW-CFP

MODFLOW-NWT

MODFLOW-OWHM

Other Notes

The MNW1 and MNW2 packages can not both be used in the same simulation.

MODFLOW Name File

The MNW2 Package is activated by including a record in the MODFLOW name file using the file type (Ftype) “MNW2” to indicate that relevant calculations are to be made in the model and to specify the related input data file. The user can optionally specify that information calculated for specific multi-node wells are to be written to separate output files by including a record in the MODFLOW name file using the file type (Ftype) “MNWI” that specifies the relevant input data file giving selected well locations. The MNW2 and MNWI Packages are compatible with MODFLOW–2000 (Harbaugh and others, 2000) and MODFLOW–2005 (Harbaugh, 2005) and with compatible versions of the groundwater transport process, but not with earlier versions of MODFLOW.

MNW2 Package Input Data

The MNW2 input file consists of input items (datasets) numbered from 0 through 4, each consisting of one or more records, as described in detail below. These data are used to specify information about the locations, flows, physical and hydraulic properties of the wells, and possibly solute concentrations, as well as specifying certain output control options.

In the following description, input parameters are indicated as being optional by their enclosure in curly brackets. All input variables are read using free formats. In free format, variables are separated by one or more spaces or by a comma and optionally one or more spaces. Thus, in free format, a blank field cannot be used to set a variable value to zero.

FOR EACH SIMULATION:

Data Set 0

[#Text]

Note 1: Item 0 can be repeated multiple times. Text will be printed to the MODFLOW listing (output) file.

 


 


 


 

[WELLID TABNAM TSFAC]

READ NLNK TIMES IF NLNK>0

Data Set 1

 

MNWMAX IWL2CB MNWPRNT [OPTION]

 


For each Multi-Node well (that is, repeat dataset 2 MNWMAX times):

Data Set 2a

WELLID NNODES

Data Set 2b

LOSSTYPE PUMPLOC Qlimit PPFLAG PUMPCAP

If LOSSTYPE NONE:

Data Set 2c

[Rw Rskin Kskin B C P CWC]

For each node (or open interval) of this well the user must use either input format 1 or input format 2; in either case, dataset 2d must have |NNODES| records:

Data Set 2d

2d-1 Input format 1, for NNODES > 0

LAY ROW COL [Rw Rskin Kskin B C P CWC PP]

2d-2 Input format 2, for NNODES < 0

Ztop Zbotm ROW COL [Rw Rskin Kskin B C P CWC]

If PUMPLOC 0:

Data Set 2e

[PUMPLAY PUMPROW PUMPCOL] [Zpump]

If Qlimit > 0:

Data Set 2f

Hlim QCUT [Qfrcmn Qfrcmx]

If PUMPCAP > 0:

Data Set 2g

Hlift LIFTq0 LIFTqmax HWtol

If PUMPCAP > 0:

Data Set 2h

LIFTn Qn

FOR EACH STRESS PERIOD:

Data Set 3

IF ITMP > 0:

For each multi-node well (that is, repeat dataset 4 ITMP times):

Data Set 4a

WELLID Qdes [CapMult] [Cprime] [xyz]

If Qlimit < 0:

Data Set 4b

Hlim QCUT [Qfrcmn Qfrcmx]

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