The RCH: Recharge package pane is on the MODFLOW Features tab of the Object Properties dialog box.
The data that can be specified for the Recharge package are the Starting time, Ending time, Recharge rate, and sometimes Recharge layer. Whether or not Recharge layer is present depends on the choice of return location in the RCH: Recharge package pane of the MODFLOW Packages and Programs dialog box. If Specified layer was selected on the RCH: Recharge package pane but Time varying recharge 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.
Starting time and Ending time are explained in the help for the MODFLOW Features tab.
Recharge rate is the recharge flux (L/t). Positive values represent flux into the groundwater.
RCH Multiplier is only used if it has been activated in the RCH: Recharge Package. If RCH Multiplier is specified, the recharge rate is multiplied by the RCH Multiplier value.
Recharge layer is the layer indicator variable. For each horizontal location, it indicates the layer to which recharge is removed. If some layers are nonsimulated, it is important to remember that Recharge layer represents the MODFLOW layer not the layer in the ModelMuse model. ModelMuse layers include both simulated and nonsimulated layers.
Auxiliary Variables If the Groundwater Transport process in MODFLOW 6 is active, auxiliary variables will be included. They represent the concentration of flow into the groundwater from the boundary. Flow out of the groundwater will be at the concentration in the cell containing the boundary.
Density: Density is the density of fluid entering groundwater from the boundary. Density is only present if the Buoyancy package is active and Specify Density is selected.
Viscosity: Viscosity is the viscosity of fluid entering groundwater from the boundary. Viscosity is only present if the Viscosity package is active and Specify Viscosity is selected.
Density and Viscosity are only used with the General Head Boundary, River, Lake, Stream, and Multiaquifer Well packages. However, they may also appear in other packages where they will be treated as auxiliary variables but not used by MODFLOW.
If parameters are used with an object, a multiplier for Recharge 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 recharge rate to apply.
