New default choice for scheme for advection of tracers (NERD) in 2D
Old default value for SCHEME FOR ADVECTION OF TRACERS (or 3rd component of TYPE OF ADVECTION) = 1 (i.e. characteristics) in TELEMAC-2D. This method is not mass conservative. The choice is to switch to a mass conservative advection scheme which works with tidal flats: NERD (= choice 13 or 14 which are the same in TELEMAC-2D).