As @sara.pavan has noticed, choice 2 ("VERTICAL DIFFUSION ONLY") for the keyword SCHEME FOR DIFFUSION OF TRACERS is useless as there is no difference if it is set to 1 or 2. It can be removed.
added module:telemac-3d label
assigned to @chi-tuan.pham
This choice was introduced between releases v6p3 and v7p0. Perhaps something was tried but no new feature had been pushed other than this choice in the dictionary (and nothing in the source files).
No differences have been noticed for the various following TELEMAC-3D examples:
amr bergenmeersen bump_static Cooper lock-exchange pildepon pluie Rouse source stratification tetra tracer_wet_dry V Viollet
between choices SCHEME FOR DIFFUSION OF TRACERS = 2 and default value (= 1).
mentioned in commit 771b2d8c
closed
mentioned in commit 0a1b2ae1
mentioned in commit 2939dfef
mentioned in issue #935
Moyen d'essai PAM - EDF R&D