Do you mean the "Inflow Area"? This is automatically reported at the top of the summary report for each node.
If the line is missing, it means there is no contributing area. What are the pond inflows?
Keep in mind that the area is always associated with the "primary" flows. If the pond has only "secondary" flows coming into it, they won't have any area associated with them. This is necessary in order to avoid "double counting" any area.
For further details, please see "Inflow Area" in the HydroCAD help index. If you still have questions please send your HydroCAD .HCP file to HydroCAD support.