I'm trying to put a tunnel next to a cut for a river and it fills the river in

[David-Vogel]

I hope this hasn't been answered somewhere else,I searched as best I could, so if it is I apologize, but please point me to the solution. I am building up a set of hills and they will have a tunnel going trough them about 10" above the base board. The hill ends at 18" tall so there is considerable hill above the track. I have a waterfall and a river flowing from it, creating a valley adjacent to the hill. If I select "standard" the river valley looks great but there is a "cut" in the hill showing the track. If I select "Tunnel" the hill looks perfect but the program adds an embankment down from the track, that fills in the valley. The track is rising inside the hill at a 1.5% grade so it is not on a flat surface.
Is there a way to have my cake and eat it too? Can I have a tunnel without the large flared support showing?

Thank you in advance for your help.

Dave

[David]

You can create a height contour with height 0 right next to the 'hidden track' to create a steep cliff.
A height contour is just a surface for which you tick 'Height contour' on the SURFACES tab when you select the surface.