Navigation: Main Menu and Buttons > Model > MODFLOW Dialog Boxes > MODFLOW Packages and Programs Dialog Box > Groundwater Transport > MT3DMS or MT3D-USGS
SSM: Sink & Source Mixing Package Pane
The SSM: Sink & Source Package pane is is on the MODFLOW Packages and Programs dialog box under MT3DMS or MT3D-USGS. It is used to specify comments related to the SSM package in MT3DMS.
Sinks and sources are specified with Objects.