BCF6 - Block-Centered Flow Package

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Abbreviation in Name file

BCF6

Purpose

The Block-Centered Flow package is used to specify properties controlling flow between cells.

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

Goode, D.J., and Appel, C.E., 1992, Finite-difference interblock transmissivity for unconfined aquifers and for aquifers having smoothly varying transmissivity: U.S. Geological Survey Water-Resources Investigations Report 92-4124, 79 p.

McDonald, M.G., Harbaugh, A.W., Orr, B.R., and Ackerman, D.J., 1992, A method of converting no-flow cells to variable-head cells for the U.S. Geological Survey modular finite-difference ground-water flow model: U.S. Geological Survey Open-File Report 91-536, 99 p.

McDonald, M.G., and Harbaugh, A.W., 1988, A modular three-dimensional finite-difference ground-water flow model: U.S. Geological Survey Techniques of Water-Resources Investigations, book 6, chap. A1, 586 p.

Related Packages

The Layer-Property Flow package (LPF) and the Hydrogeologic-Unit Flow package (HUF2) are two other packages that can be used to specify properties controlling flow between cells.

The Horizontal Flow Barrier (HFB) package modifies the horizontal conductances between certain, specified pairs of cells.

Supported in

MODFLOW-2000

MODFLOW-2005

MODFLOW-LGR

MODFLOW-CFP

MODFLOW-NWT

MODFLOW-OWHM

Other Notes

Every model must  use one and only one of the four packages (BCF6, LPF, HUF2, and UPW) that are used to specify properties controlling flow between cells. UPW is only available in MODFLOW-NWT and MODFLOW-OWHM.

If the BCF package is used together with the UZF package, IUZFOPT in the UZF package must be set to 1.

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

The SOR solver doesn't work well with the wetting capability.

Input Instructions

This version of the Block-Centered Flow (BCF) Package combines the capabilities documented in McDonald and Harbaugh (1988), McDonald and others (1992), and Goode and Appel (1992). Input for the BCF Package is read from the file that is type "BCF6" in the name file. The file type has been changed from that used in MODFLOW-96, which was “BCF”, because the input data are not compatible.

FOR EACH SIMULATION

Data Set 1

IBCFCB HDRY IWDFLG  WETFCT IWETIT IHDWET

These 6 variables are free format if the option “FREE” is specified in the Basic Package input file; otherwise, the variables all have 10-character fields.

Data Set 2

Ltype(NLAY)

Read one value for each layer. These values are free format if the word FREE is specified in Item 1 of the Basic Package input file; otherwise, they have fixed-format fields. The fixed format fields are each 2 characters wide with 40 values per line. Use only as many lines as required for the number of model layers.

In MODFLOW-2005 v 1.5 and earlier versions of MODFLOW-2005, Ltype must always be in free format.

Data Set 3

TRPY(NLAY) -- U1DREL

A subset of the following two-dimensional variables are used to describe each layer. The variables needed for each layer depend on the layer-type code (LAYCON, which is defined as part of the Item-2 Ltype), whether the simulation has any transient stress periods (at least one stress period defined in the Discretization File specifies Ss/Tr as “TR”), and if the wetting capability is active (IWDFLG not 0). If a variable is not needed, it must be omitted. In no situation will all variables be required. The required variables (Items 4-9) for layer 1 are read first; then the variables for layer 2 and so forth.

Data Set 4

[Sf1(NCOL,NROW)]--U2DREL

If there is at least one transient stress period.

Data Set 5

[Tran(NCOL,NROW)] -- U2DREL

If LAYCON is 0 or 2 (see Ltype ), then read item 5.

Data Set 6

[HY(NCOL,NROW)] -- U2DREL

Otherwise, if LAYCON is 1 or 3 (see Ltype), read item 6.

Data Set 7

[Vcont(NCOL,NROW)] -- U2DREL

If not the bottom layer.

Data Set 8

[Sf2(NCOL,NROW)] -- U2DREL

If there is at least one transient stress period and LAYCON (see Ltype) is 2 or 3.

Data Set 9

[WETDRY(NCOL,NROW)] -- U2DREL

If IWDFLG is not 0 and LAYCON is 1 or 3 (see Ltype).