Insert simple panel line?

First image shows the kinds of panel lines a little exaggerated so you can see the topology. Basically I just want to have two lines or one line dip down in a flat or curved surface (as in second image).

Second image shows the rhino solid. The line marked with green (2) should be the panel line.

As you can see I duplicated the curve on the surface, but it is not connected to the topology, so I cant create the effect this way.
I would now go about this creating a shape to boolean-subtract out of there, but wonder if i might have just missed an easier solution.

Looking forward to your answers!

The “MatchOnCurve” script may be useful for you, because it lets you match a curve end to the inside of another curve. Rhino’s default “Match curve” tool can’t do this, because it only matches to the end of curves.
MatchOnCurve.rar (3.3 KB)

How to use a script? In this case, my script is saved in the following directory:
D:\PROGRAMI\Rhinoceros 6\scripts\MatchOnCurve

I assigned the script to the right mouse button function of the “Match curve” tool with the following alias:
_-RunPythonScript “D:\PROGRAMI\Rhinoceros 6\scripts\MatchOnCurve\”

For a Tooltip I used “Match on curve”.

You need to draw your channel profile in a side view and use the aforementioned script to match its both ends to the profile of your 3d model above. Once you do that, you need to use the “Revolve” tool to create a rounded extrusion (Rhino lets you make a full circle revolve or a partial one - depending of your preference) of the channel that you want to add. Then you can split or trim the unnecessary portion of the model.