The ETS: Evapotranspiration Segments package pane is on the MODFLOW Features tab of the Object Properties dialog box.
The data that can be specified for the Evapotranspiration Segments package are the Starting time, Ending time, Evapotranspiration rate, Evapotranspiration surface, Evapotranspiration depth, several copies of Fractional rate[i] and Fractional depth[i] and sometimes Evapotranspiration layer. Whether or not Evapotranspiration layer is present depends on the choice of return location in the ETS: Evapotranspiration Segments package pane of the MODFLOW Packages and Programs dialog box. If Specified layer was selected on the ETS: Evapotranspiration Segments package pane but Time varying ETS layers was not selected, the layer at any location will be determined by the layer of the lowest cell selected by the object at that location. The number of copies of Fractional rate[i] and Fractional depth[i] that are present depends on the Number of segments defined in the ETS: Evapotranspiration Segments package pane of the MODFLOW Packages and Programs dialog box. The number of copies of Fractional rate[i] and Fractional depth[i] will each be one less than the Number of segments.
Of these data, all but Fractional rate[i], Fractional depth[i], and EVT Multiplier are also present in the Evapotranspiration package and are described in the help for the EVT: Evapotranspiration Package Pane.
Starting time and Ending time are explained in the help for the MODFLOW Features tab.
EVT Multiplier is only used if it has been activated in the ETS: Evapotranspiration Segments Package. If EVT Multiplier is specified, the evapotranspiration rate is multiplied by the EVT Multiplier value.
Fractional depth[i] is a proportion of the extinction depth (dimensionless), measured downward from the ET surface, which, with Fractional rate[i], defines the shape of the relation between the evapotranspiration rate and head. The value of Fractional depth[i] must be between 0.0 and 1.0, inclusive. Repetitions of Fractional depth[i] and Fractional rate[i] are read in sequence such that the first occurrence represents the bottom of the first (uppermost) segment, and subsequent repetitions represent the bottom of successively lower segments. Accordingly, Fractional depth[i] values for later repetitions (representing lower segments) should be greater than Fractional depth[i] values for earlier repetitions.
Fractional rate[i] is a proportion of the maximum evapotranspiration rate (dimensionless) which, with Fractional depth[i], defines the shape of the relation between the evapotranspiration rate and head. The value of Fractional rate[i] should be between 0.0 and 1.0, inclusive. Repetitions of Fractional depth[i] and Fractional rate[i] are read in sequence such that the first occurrence represents the bottom of the first (uppermost) segment, and subsequent repetitions represent the bottoms of successively lower segments. Accordingly, Fractional rate[i] values for later repetitions (representing lower segments) generally would be less than Fractional rate[i] values for earlier repetitions.
If parameters are used with an object, a multiplier for Evapotranspiration rate must be defined for each parameter. MODFLOW will multiply the multiplier by the parameter value (specified in the MODFLOW Packages and Programs dialog box) to determine the evapotranspiration rate to apply.
