GMS:Calculate Mass

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MT3DMS
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ICBUND Array
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Post-processing
MT3DMS Display Options
Importing an MT3DMS Simulation
Calculate Mass
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Basic Transport Package Dialog
MT3DMS Source/Sink Mixing Package
Chemical Reaction Package
Transport Observation Package

The MT3DMS Calculate Mass dialog allows the calculation of the mass of a contaminant in the entire model domain or in the selected cells. The dialog is reached through the Calculate Mass command in either MT3DMS menu or the PHT3D menu. The appropriate datasets must already exist in the project before this dialog can be accessed.

At the top of the dialog, the MODFLOW Heads and MT3DMS Conc... buttons bring up a Select Dataset dialog where the head and concentration datasets can be selected. All time steps in the datasets can be used or specific time steps can be selected. Selecting the Calculate button will populate the table on the right with the mass at each time step.

Definition

Explains the formula that is used to calculate the mass. Basically, the volume of water in each cell is calculated and then multiplied by the concentration computed by MT3DMS. A conversion factor must be supplied so that the calculated mass will be computed in the correct units.

Concentration Range

Allows the specification a range over which the mass will be calculated. This is most useful to ignore negative concentrations that result in MT3DMS simulations.

By default, the range of the selected dataset is used. Turning on the Specify range in calculation option allows using a specific range inside the dataset by setting the minimum and maximum values.

Conversion Factor

The Factor determines which units the resulting mass will be displayed in.

Example of the MT3DMS Calculate Mass dialog.