Specified heads can be set up in several ways.
In the Basic package, IBOUND is used to identify specified head boundaries and STRT gives the head at those boundaries.
The Time-Variant Specified-Head package can be used.
The Flow and Head Boundary package can be used.
Specified heads specified by the Time-Variant Specified-Head package override those specified by a combination of IBOUND and STRT in the Basic package.
Specified heads specified by the Flow and Head Boundary package override those specified either by a combination of IBOUND and STRT in the Basic package or by the Time-Variant Specified-Head package.
The Time-Variant Specified-Head package allows parameters to be used for specified heads. Parameters can not be used with the other options.
