GMS:PCB Package

Example of the MODFLOW Prescribed Concentration Boundary (PCB) Package dialog

The Prescribed Concentration Boundary (PCB) package is only used when there is a constant concentration boundary condition in the MODFLOW-USG Transport simulation.

A constant concentration boundary condition can be assigned to a the MODFLOW-USG Tranport model by using the MODFLOW/MT3DMS Source/Sinks dialog for either selected cells or in the conceptual model.

In the MODFLOW Prescribed Concentration Boundary (PCB) Package dialog, the following can be edited:

• Stress period – Species which stress period is displayed in the table.
• Use previous – Use this option on a stress period to use the values from the previous stress period for the current stress period. This option is unavailable for steady state models and the first stress period of transient models.
• Edit All Use Previous – This button brings up a spreadsheet allowing the user to quickly edit the Use Previous flag for all stress periods.
• cell ID – Changing the cell ID will change which cell contains the concentration boundary.
• Species ID – List which species has been assigned to the cell. Will only accept values corresponding to existing species as defined in the BCT Process.
• Concentration – The concentration value assigned to the cell.
• Delete All – This button deletes all values in the dialog.