GMS:MT3DMS Point Sources/Sinks BC

The Source/Sink Mixing Package dialog can be used to edit both point and areal sources/sinks using a spreadsheet. In many cases, it is more convenient to view and edit source sink concentrations on a cell-by-cell basis. Two commands are provided to facilitate this type of editing: the Point Sources/Sinks command and the Areal Sources/Sinks command.

Point Sources/Sinks

The Point Sources/Sinks command is used to assign and edit the concentrations at point sources and sinks. Before selecting the Point Sources/Sinks command, a set of cells should be selected using the cell selection tools. Once the command is selected, the MT3DMS Point Source/Sink dialog appears.

A point source/sink concentration for each species is assigned to the selected cells by selecting the toggle corresponding to the type of source/sink. The concentration at the cells can be specified as either constant or transient. If a constant value is specified, this number will be used for all stress periods. If the Variable option is used, clicking on the window brings up the XY Series Editor. The XY Series Editor is used to assign a concentration value for each stress period.

Multiple Sources/Sinks per Cell

In many cases, multiple point sources/sinks, each having a different type, can be assigned to an individual cell. In this case, the toggle for each type should be selected and the concentration specified. It is also possible for multiple sources/sinks of the same type to be assigned to a single cell. However, MT3DMS only allows one concentration to be assigned to each type for a single cell. In such cases, the specified concentration for that type applies to all sources/sinks of that type within the cell.

Fixing Concentrations for Selected Species

When entering the concentrations for a specified concentration cell, it is sometimes necessary to specify the concentrations of some of the species but allow the concentrations for the remaining species to vary. This can be accomplished by specifying a negative concentration for the species that are to vary.

Areal Sources/Sinks

The Areal Sources/Sinks command is used to edit the concentrations assigned to recharge and evapotranspiration fluxes. Before selecting the Areal Sources/Sinks command, a set of cells should be selected using the cell selection tools. The concentration fluxes due to recharge and evapotranspiration are applied to vertical columns rather than to individual cells. Therefore, to edit the value for a vertical column, any cell in the column can be selected. Once the Areal Sources/Sinks command is selected, the MT3DMS Areal Sources/Sinks dialog appears.

The areal source/sink concentration values at the selected cells can be edited by highlighting a species and either selecting a constant value for all stress periods, or by defining a set of values.

See also

• Cell Attributes