Only one package related to output can be selected in the MODFLOW Packages and Programs dialog box; the HYDMOD package.
Other packages are activated in other ways.
The Output Control option is always active and its options are specified in the MODFLOW Output Control dialog box
The Gage package (which works with the SFR and LAK packages) is activated by specifying a gage in the Object Properties dialog box.
The MNWI package (which works with the MNW2 package) is activated by specifying MNWI information on the Object Properties dialog box.
