HFB6 - Horizontal Flow Barrier Package

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Abbreviation in Name file

HFB6

Purpose

The Horizontal Flow Barrier package is used to simulate barriers to flow such as slurry walls by reducing the conductance between individual pairs of cells.

Documentation

Related Packages

One of the flow packages, Block-Centered Flow package (BCF), Layer-Property Flow package (LPF) or the Hydrogeologic-Unit Flow package (HUF2) sets the conductance between cells that is modified by the Horizontal Flow Barrier package.

Supported in
•MODFLOW-2000
•MODFLOW-2005

Other Notes

The "Model-Layer Variable-Direction Horizontal Anisotropy" (LVDA) capability is incompatible with the Horizontal Flow Barrier package.

Input Instructions

The Horizontal Flow Barrier Package is documented in Hsieh and Freckleton (1993). Input for the Horizontal Flow Barrier (HFB) Package is read from the file that has file type “HFB6” in the name file. The file type has been changed from that used in MODFLOW-96, which was “HFB”, because the input data are not compatible. All variables are read in free format.

FOR EACH SIMULATION

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.

1.

NPHFB MXFB NHFBNP Option

NPHFB—is the number of horizontal-flow barrier parameters to be defined in Items 2 and 3. Note that for an HFB parameter to have an effect in the simulation, it must be defined in Items 2 and 3 and made active using Item 6.

The maximum number of parameters in all packages taken together is 999.

MXFB—is the maximum number of HFB barriers that will be defined using parameters.

NHFBNP—is the number of HFB barriers not defined by parameters.

Option—is an optional list of character values.

•NOPRINT—suppresses the printing of cell lists.

Repeat Items 2 and 3 for each NPHFB parameter. Items 2 and 3 are not read if NPHFB is negative or zero.

2.

PARNAM PARTYP Parval NLST

PARNAM—is the name of a parameter. 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 will be equivalent. All parameter names must be unique.

PARTYP—is the type of parameter. For the HFB Package, the only allowed parameter type is HFB, which defines values of the hydraulic characteristic of the barrier.

Parval—is the parameter value. This parameter value may be overridden by a value in the Sensitivity (SEN) Process input file or by a value generated by the Parameter-Estimation (PES) Process.

NLST—is the number of horizontal-flow barrier cells included in the parameter.

3.

Layer IROW1 ICOL1 IROW2  ICOL2 Factor

NLST repetitions of Item 3 are required; they are read by module ULSTRD. (SFAC of the ULSTRD utility module applies to Factor).

Layer—is the number of the model layer in which the horizontal-flow barrier is located.

IROW1—is the row number of the cell on one side of the horizontal-flow barrier.

ICOL1—is the column number of the cell on one side of the horizontal-flow barrier.

IROW2—is the row number of the cell on the other side of the horizontal-flow barrier.

ICOL2—is the column number of the cell on the other side of the horizontal-flow barrier.

Factor—is the factor used to calculate hydraulic characteristic from the parameter value. The hydraulic characteristic is the product of Factor and the parameter value.

4.

Layer IROW1 ICOL1 IROW2  ICOL2 Hydchr

NHFBNP repetitions of Item 4 are read. Item 4 is not read if NHFBNP is negative or zero.

Layer—is the number of the model layer in which the horizontal-flow barrier is located.

IROW1—is the row number of the cell on one side of the horizontal-flow barrier.

ICOL1—is the column number of the cell on one side of the horizontal-flow barrier.

IROW2—is the row number of the cell on the other side of the horizontal-flow barrier.

ICOL2—is the column number of the cell on the other side of the horizontal-flow barrier.

Hydchr—is the hydraulic characteristic of the horizontal-flow barrier. The hydraulic characteristic is the barrier hydraulic conductivity divided by the width of the horizontal-flow barrier.

5.

NACTHFB—is the number of active HFB parameters.

6.

Pname

NACTHFB repetitions of Item 6 are read. Item 6 is not read if NACTHFB is negative or zero.

Pname—is the name of a parameter to be used in the simulation. NACTHFB parameter names will be read.