In order for the applied infiltration to pass through the unsaturated zone, the Newton formulation must be used because the initial head will be below the bottom of the cells in the unsaturated zone. If the Newton formulation is not used, those cells will convert to dry and become inactive. Infiltration applied to inactive cells will be ignored.
Activate the Newton formulation on the Wetting tab of the "Model|MODFLOW Options" dialog box.
Screen capture of the MODFLOW Options dialog box illustrating the activation of the Newton formulation.
