Hello Toby,
I will have to investigate deeper to understand what is done in LIPS for dry areas or close to wet-dry transitions. I am not a specialist of LIPS implementation.
I think numerical options for GAIA come from recommended options for SISYPHE and SEDI-3D but I do not know who did the choices when they were not the same for the 2 old modules (or when a different choice was done).
Currently, it is recommended to use GAIA in 2D and 3D. SEDI-3D still exists but is not compatible with everything and is supposed to be deleted soon as already done for SISYPHE, see
gitlab.pam-retd.fr/otm/telemac-mascaret/-/issues/921
Best regards,
Chi-Tuan