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Reach Stage
This category is dependent on selection of the Link to MODFLOW 2000 RIP ET method in the Groundwater Computation category; see Link to MODFLOW 2000 RIP ET. This category should be used in conjunction with the Reach Gain Loss category on which a method other than None should be selected.
* None
This is the default method. There are no slots associated with this method.
* Weighted Interpolation
Note:  RiverWare’s connection with MODFLOW is currently not functional. This method has been disabled and cannot be selected. An error will be posted at model load if this method was previously selected. Contact CADSWES for help.
This method calculates a stage elevation for each of the MODFLOW cells specified by the user in the Reach Stage and GainLoss Map slot. The stage is interpolated from between the Reach.Inflow Stage and Reach.Outflow Stage and is shown in the Reach Stage to MODFLOW slot. The calculated stage, for each cell in the Reach Stage to MODFLOW slot, is transferred to MODFLOW and used in the RIV package calculations. Figure 8.10 shows the interpolation equation. In some cases the river channel may span more than one cell in width, when this occurs the user can choose to set their weights so that all cells along a row will receive the same stage.
Slots Specific to This Method
 Reach Stage and GainLoss Map
Type: Table slot
Units: No units
Description: Maps a MODFLOW cell(s) to a Reach specified on the subbasin
Information: The layer, row, and column of each MODFLOW RIV cell is input by the user and the corresponding Reach object needs to be set as the row title. Interpolation weights corresponding to the Inflow Stage and the Outflow Stage on the Reach also need to be input for each MODFLOW RIV cell. The sum of the Inflow Stage Weigth and Outflow Stage Weight for a single cell should add up to 1.
I/O: Input only
 
 
Layer
Row
Column
Inflow Stage Weight
Outflow Stage Weight
Reach0
1
1
4
0.8
0.2
Reach0
1
2
4
0.5
0.5
Reach1
1
4
6
0.7
0.3
Reach1
1
4
7
0.7
0.3
 Reach Stage to MODFLOW
Type: Table Series slot
Units: Length
Description: Interpolated stage (elevation) value for each MODFLOW cell specified in the Reach Stage and GainLoss Map slot. The column labels are automatically defined at the beginning of the run, in MODFLOW initialization. The user unit configuration (m, ft, and so on) selected on this slot must match with the units used in MODFLOW.
Information: Transferred to MODFLOW
I/O: Output only
 
 
Reach1
1,1,4
m
Reach1
1,2,4
m
Reach2
1,8,6
m
Reach2
1,9,7
m
t
553.2
552.7
551.4
550.9
t+1
553.32
552.5
551.7
550.8
t+2
553.27
552.6
551.5
550.9
Figure 8.10  Stage Interpolation Equation
Figure 8.11  Example mapping of MODFLOW cells to reach objects for interpolation and summation
Revised: 08/02/2021