GWF-DIS

Structure of Blocks

FOR EACH SIMULATION

    BEGIN OPTIONS
      [LENGTH_UNITS <length_units>]
      [NOGRB]
      [XORIGIN <xorigin>]
      [YORIGIN <yorigin>]
      [ANGROT <angrot>]
      [EXPORT_ARRAY_ASCII]
    END OPTIONS

    BEGIN DIMENSIONS
      NLAY <nlay>
      NROW <nrow>
      NCOL <ncol>
    END DIMENSIONS

    BEGIN GRIDDATA
      DELR
            <delr(ncol)> -- READARRAY
      DELC
            <delc(nrow)> -- READARRAY
      TOP
            <top(ncol, nrow)> -- READARRAY
      BOTM [LAYERED]
            <botm(ncol, nrow, nlay)> -- READARRAY
      [IDOMAIN [LAYERED]
            <idomain(ncol, nrow, nlay)> -- READARRAY]
    END GRIDDATA

Explanation of Variables

Block: OPTIONS

length_units is the length units used for this model. Values can be “FEET”, “METERS”, or “CENTIMETERS”. If not specified, the default is “UNKNOWN”.
NOGRB keyword to deactivate writing of the binary grid file.
xorigin x-position of the lower-left corner of the model grid. A default value of zero is assigned if not specified. The value for XORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
yorigin y-position of the lower-left corner of the model grid. If not specified, then a default value equal to zero is used. The value for YORIGIN does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
angrot counter-clockwise rotation angle (in degrees) of the lower-left corner of the model grid. If not specified, then a default value of 0.0 is assigned. The value for ANGROT does not affect the model simulation, but it is written to the binary grid file so that postprocessors can locate the grid in space.
EXPORT_ARRAY_ASCII keyword that specifies input griddata arrays should be written to layered ascii output files.

Block: DIMENSIONS

nlay is the number of layers in the model grid.
nrow is the number of rows in the model grid.
ncol is the number of columns in the model grid.

Block: GRIDDATA

delr is the column spacing in the row direction.
delc is the row spacing in the column direction.
top is the top elevation for each cell in the top model layer.
botm is the bottom elevation for each cell.
idomain is an optional array that characterizes the existence status of a cell. If the IDOMAIN array is not specified, then all model cells exist within the solution. If the IDOMAIN value for a cell is 0, the cell does not exist in the simulation. Input and output values will be read and written for the cell, but internal to the program, the cell is excluded from the solution. If the IDOMAIN value for a cell is 1 or greater, the cell exists in the simulation. If the IDOMAIN value for a cell is -1, the cell does not exist in the simulation. Furthermore, the first existing cell above will be connected to the first existing cell below. This type of cell is referred to as a “vertical pass through” cell.

Example Input File

Example 1

    #The OPTIONS block is optional
    BEGIN OPTIONS
      LENGTH_UNITS METERS
    END OPTIONS
    
    #The DIMENSIONS block is required
    BEGIN DIMENSIONS
      NLAY 10
      NROW 1
      NCOL 21
    END DIMENSIONS
    
    #The GRIDDATA block is required
    BEGIN GRIDDATA
      DELR
        INTERNAL FACTOR 1.
    	.1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 0.01
      DELC
        CONSTANT 1.0
      TOP LAYERED
        CONSTANT 1.
      BOTM LAYERED
        CONSTANT 0.9
        CONSTANT 0.8
        CONSTANT 0.7
        CONSTANT 0.6
        CONSTANT 0.5
        CONSTANT 0.4
        CONSTANT 0.3
        CONSTANT 0.2
        CONSTANT 0.1
        CONSTANT 0.0
    END GRIDDATA

Example 2

    BEGIN OPTIONS
      LENGTH_UNITS METERS
    END OPTIONS
    
    BEGIN DIMENSIONS
      NODES 9
      NJA 33
    END DIMENSIONS
    
    BEGIN GRIDDATA
      TOP
        CONSTANT 0.
      BOT
        CONSTANT -10
      AREA
        INTERNAL FACTOR 1
          10000 10000 10000 10000 10000 10000 10000 10000 10000
    END GRIDDATA
    
    BEGIN CONNECTIONDATA
      IHC
        CONSTANT 1
      IAC
        INTERNAL FACTOR 1
        3 4 3 4 5 4 3 4 3
      JA
        INTERNAL FACTOR 1
        1 2 4
        2 1 3 5
        3 2 6
        4 1 5 7
        5 2 4 6 8
        6 3 5 9
        7 4 8
        8 5 7 9
        9 6 8
      CL12
        INTERNAL FACTOR 1
        0 50 50
        0 50 50 50
        0 50 50
        0 50 50 50
        0 50 50 50 50
        0 50 50 50
        0 50 50
        0 50 50 50
        0 50 50
      HWVA
        INTERNAL FACTOR 1
        0 100 100
        0 100 100 100
        0 100 100
        0 100 100 100
        0 100 100 100 100
        0 100 100 100
        0 100 100
        0 100 100 100
        0 100 100
    END CONNECTIONDATA

Example 3

    #The OPTIONS block is optional
    BEGIN OPTIONS
      LENGTH_UNITS METERS
    END OPTIONS
    
    #The DIMENSIONS block is required
    BEGIN DIMENSIONS
      NCPL 4
      NLAY 3
      NVERT 9
    END DIMENSIONS
    
    #The GRIDDATA block is required
    BEGIN GRIDDATA
      TOP
        CONSTANT 3.0
      BOTM LAYERED
        CONSTANT 2.0
        CONSTANT 1.0
        CONSTANT 0.0
      IDOMAIN LAYERED
        INTERNAL FACTOR 1
          1 1 1 0
        CONSTANT 1
        CONSTANT 1
    END GRIDDATA
    
    #The VERTICES block is required
    BEGIN VERTICES
      1 0. 1.
      2 .5 1.
      3 1. 1.
      4 0 .5
      5 .5 .5
      6 1. .5
      7 0. 0.
      8 .5 0.
      9 1. 0.
    END VERTICES
    
    BEGIN CELL2D
      1 .25 .75 4 1 2 5 4
      2 .75 .75 4 2 3 6 5
      3 .25 .25 4 4 5 8 7
      4 .75 .25 4 5 6 9 8
    END CELL2D