Hello,
FRICTION COEFFICIENT is meant for Telemac-2D and in 3D it is FRICTION COEFFICIENT FOR THE BOTTOM. It seems that you are running Telemac-3D with a steering file done for Telemac-2D. You should better inspire from a steering file in the Telemac-3D test cases. As a matter of fact, if some keywords are the same there are a number of differences, please refer to user manuals.
With best regards,
Jean-Michel Hervouet