GMS:MF6 NPF Package

The Node Property Flow (NPF) Package dialog

The Node Property Flow (NPF) Package dialog is accessed by double-clicking on the NPF package under a MODFLOW 6 simulation in the Project Explorer. It contains the following sections and options:

• Sections list – A list of sections that can be turned on or off:
  • Comments – Turn on to make the Comments section visible.
  • Options – Turn on to make the Options section visible.
  • GridData – Turn on to make the GridData section visible. This section is on by default.
• Comments section – Enter general alphanumeric comments. Comments entered here get written at the top of the file, preceded by a '#' symbol.
• Options section
  • Save flows to budget file (SAVE_FLOWS) – Turn on to write cell-by-cell flow terms to the file specified with "BUDGET SAVE FILE" in Output Control.
  • Alternative conductance calculation method (ALTERNATIVE_CELL_AVERAGING) – Turn on to use an alternative method for calculating the conductance for horizontal cell connections.
    • "Logarithmic" –
    • "AMT-LMK" – Conductance will be calculated using arithmetic-mean thickness and logarithmic-mean hydraulic conductivity.
    • "AMT-HMK" – Conductance will be calculated using arithmetic-mean thickness and harmonic-mean hydraulic conductivity.
  • Cells with negative ICELLTYPE are confined (THICKSTRT) – Cells having a negative ICELLTYPE are confined, and their cell thickness for conductance calculations will be computed as STRT-BOT rather than TOP-BOT.
  • Calculate vertical conductance (VARIABLECV) – Vertical conductance will be calculated using the saturated thickness and properties of the overlying cell and the thickness and properties of the underlying cell.
    • Dewatered (DEWATERED) – Vertical conductance is calculated using only the saturated thickness and properties of the overlying cell if the head in the underlying cell is below its top.
  • Perched (PERCHED) – When a cell is overlying a dewatered convertible cell, the head difference used in Darcy's Law is equal to the head in the overlying cell minus the bottom elevation of the overlying cell.
  • REWET – Turn on to activate model rewetting.
    • WETFCT – A factor included in the calculation of the head, initially established at a cell when that cell is converted from dry to wet.
    • IWETIT – Iteration interval for attempting to wet cells.
    • IHDWET – Integer flag that determines which equation is used to define the initial head at cells that become wet.
  • Use XT3D formulation (XT3D) – Turn on to use the XT3D formulation.
    • Add XT3D terms to right-hand side (RHS) – The XT3D additional terms will be added to the right-hand side instead of the coefficient matrix.
  • Save specific discharge (SAVE_SPECIFIC_DISCHARGE) – Turn on to calculate x, y, and z components of specific discharge at cell centers and write them to the cell-by-cell flow file as specified with "BUDGET SAVE FILE" in Output Control.
• GridData section – Contains a number of tabs, including:
  • ICELLTYPE – A flag for each cell that specifies how saturated thickness is treated.
    • Layered – Turn on if there is more than one affected layer. Select the desired layer from the drop down in order to edit the array (if "Array" is selected from the drop-down).
    • If "Constant" is selected from the drop-down, enter a decimal value in the Constant field to be applied to all cells in the layer(s).
    • If "Array" is selected from the drop-down, a user-editable array appears below the drop-down. Enter a decimal Factor value to the right of the drop-down. The individual elements of the array are multiplied by the factor value after they are read.
    • Dataset to Array... – Click to open the Select Dataset dialog. Select the desired database(s) in this dialog.
  • K – The hydraulic conductivity.
    • Layered – Turn on if there is more than one affected layer. Select the desired layer from the drop down in order to edit the array (if "Array" is selected from the drop-down).
    • If "Constant" is selected from the drop-down, enter a decimal value in the Constant field to be applied to all cells in the layer(s).
    • If "Array" is selected from the drop-down, a user-editable array appears below the drop-down. Enter a decimal Factor value to the right of the drop-down. The individual elements of the array are multiplied by the factor value after they are read.
    • Dataset to Array... – Click to open the Select Dataset dialog. Select the desired database(s) in this dialog.
  • K22 – The hydraulic conductivity of the second ellipsoid axis.
    • Define – Turn on if K22 needs to be defined.
    • Layered – Turn on if there is more than one affected layer. Select the desired layer from the drop down in order to edit the array (if "Array" is selected from the drop-down).
    • If "Constant" is selected from the drop-down, enter a decimal value in the Constant field to be applied to all cells in the layer(s).
    • If "Array" is selected from the drop-down, a user-editable array appears below the drop-down. Enter a decimal Factor value to the right of the drop-down. The individual elements of the array are multiplied by the factor value after they are read.
    • Dataset to Array... – Click to open the Select Dataset dialog. Select the desired database(s) in this dialog.
  • K33 – The hydraulic conductivity of the third ellipsoid axis.
    • Define – Turn on if K33 needs to be defined.
    • Layered – Turn on if there is more than one affected layer. Select the desired layer from the drop down in order to edit the array (if "Array" is selected from the drop-down).
    • If "Constant" is selected from the drop-down, enter a decimal value in the Constant field to be applied to all cells in the layer(s).
    • If "Array" is selected from the drop-down, a user-editable array appears below the drop-down. Enter a decimal Factor value to the right of the drop-down. The individual elements of the array are multiplied by the factor value after they are read.
    • Dataset to Array... – Click to open the Select Dataset dialog. Select the desired database(s) in this dialog.
  • ANGLE1 – The first sequential rotation angle of the hydraulic conductivity tensor in degrees.
    • Define – Turn on if ANGLE1 needs to be defined.
    • Layered – Turn on if there is more than one affected layer. Select the desired layer from the drop down in order to edit the array (if "Array" is selected from the drop-down).
    • If "Constant" is selected from the drop-down, enter a decimal value in the Constant field to be applied to all cells in the layer(s).
    • If "Array" is selected from the drop-down, a user-editable array appears below the drop-down. Enter a decimal Factor value to the right of the drop-down. The individual elements of the array are multiplied by the factor value after they are read.
    • Dataset to Array... – Click to open the Select Dataset dialog. Select the desired database(s) in this dialog.
  • ANGLE2 – The second sequential rotation angle of the hydraulic conductivity tensor in degrees.
    • Define – Turn on if ANGLE2 needs to be defined.
    • Layered – Turn on if there is more than one affected layer. Select the desired layer from the drop down in order to edit the array (if "Array" is selected from the drop-down).
    • If "Constant" is selected from the drop-down, enter a decimal value in the Constant field to be applied to all cells in the layer(s).
    • If "Array" is selected from the drop-down, a user-editable array appears below the drop-down. Enter a decimal Factor value to the right of the drop-down. The individual elements of the array are multiplied by the factor value after they are read.
    • Dataset to Array... – Click to open the Select Dataset dialog. Select the desired database(s) in this dialog.
  • ANGLE3 – The third sequential rotation angle of the hydraulic conductivity tensor in degrees.
    • Define – Turn on if ANGLE3 needs to be defined.
    • Layered – Turn on if there is more than one affected layer. Select the desired layer from the drop down in order to edit the array (if "Array" is selected from the drop-down).
    • If "Constant" is selected from the drop-down, enter a decimal value in the Constant field to be applied to all cells in the layer(s).
    • If "Array" is selected from the drop-down, a user-editable array appears below the drop-down. Enter a decimal Factor value to the right of the drop-down. The individual elements of the array are multiplied by the factor value after they are read.
    • Dataset to Array... – Click to open the Select Dataset dialog. Select the desired database(s) in this dialog.
  • WETDRY – A combination of the wetting threshold and a flag to indicate which neighboring cells can cause a cell to become wet.
    • Define – Turn on if WETDRY needs to be defined.
    • Layered – Turn on if there is more than one affected layer. Select the desired layer from the drop down in order to edit the array (if "Array" is selected from the drop-down).
    • If "Constant" is selected from the drop-down, enter a decimal value in the Constant field to be applied to all cells in the layer(s).
    • If "Array" is selected from the drop-down, a user-editable array appears below the drop-down. Enter a decimal Factor value to the right of the drop-down. The individual elements of the array are multiplied by the factor value after they are read.
    • Dataset to Array... – Click to open the Select Dataset dialog. Select the desired database(s) in this dialog.

Related Topics

• MODFLOW 6