Yes – RORB does not calculate baseflow. There are two methods for handling this:
1 – You separate out the baseflow from the gauge hydrograph before you copy it into the storm file. That way you are comparing gauged and modelled surface runoff only.
2 – You separate out the baseflow from the gauge hydrograph, then add this baseflow hydrograph into the RORB catchment file using an inflow. Then you will be comparing gauged and modelled total flow.
The first method is generally the easiest.