Time Tab

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This tab is on the SFR: Stream-Flow Routing package pane of the MODFLOW Features tab of the Object Properties dialog box. It is used to specify the time periods during which a particular object will be used to define streams in the SFR package and to specify the method by which the stage of the streams will be calculated.

Starting time and Ending time are explained in the help for the MODFLOW Features tab. However, if a parameter is used with a stream segment, the starting and Starting time and Ending time will be determined by the starting and ending times defined for the parameter instance on the SFR: Stream-Flow Routing package pane of the MODFLOW Packages and Programs dialog box.

Parameter and Parameter instance

Parameter is the name of the parameter that is used with the segment. Parameter instance defines a time period that will be used with Parameter.

Stage calculation (ICALC)

ICALC is used to indicate method used to calculate stream depth in this segment.

•If ICALC = 0, stream depth in each reach is specified at the beginning of a stress period and remains unchanged unless flow at the midpoint of a reach is zero, then depth is set to zero in that reach. No unsaturated flow is allowed.

•If ICALC > 0, stream depth is calculated and updated each iteration of the MODFLOW solver within a time step.

•If ICALC = 1, stream depth is calculated using Manning’s equation and assuming a wide rectangular channel. Unsaturated flow is simulated when the user has chosen to simulate unsaturated flow on the SFR: Stream-Flow Routing package pane of the MODFLOW Packages and Programs dialog box.

The channel variables are defined on the Channel tab.

•If ICALC = 2, stream depth is calculated using Manning’s equation and assuming an eight-point channel cross section for each segment (which allows for the computation of a wetted perimeter and for changing hydraulic conductance of the streambed in relation to changes in flow). Unsaturated flow is simulated when the user has chosen to simulate unsaturated flow on the SFR: Stream-Flow Routing package pane of the MODFLOW Packages and Programs dialog box.

The channel variables are defined on the Channel tab.

•If ICALC = 3, stream depth and width are calculated using a power function relating each to streamflow (Q)

DEPTH(y) = CDPTH × QFDPTH and

WIDTH(w) = AWDTH × QBWDTH.

No unsaturated flow is allowed. The equations are defined on the Equation tab.

•If ICALC = 4, stream depth and width are calculated using a table relating streamflow to depth and width (the table is defined in Part 4f). No unsaturated flow is allowed.

The flow table is defined on the Flow Table tab.