Hello,
If the variation in time is constant in space, you can use the functions SL, VIT, and give for example SL = your function of time instead of SL = COTE(I) as in the standard subroutine. SL is the free surface and the current time is AT, it is seen by function SL by the command USE DECLARATIONS_TELEMAC2D.
If the variation is not constant in space you can program it in bord.f, in this case you should know that the only role of bord.f is to give the prescribed values of velocities :
UBOR(K,1), VBOR(K,1) and HBOR(K) in a loop on boundary points K, so basically you can erase all the subroutine if you give them with your own formula.
An example where this is done is the the case 028_ondem2, where only HBOR is necessary.
Regards,
Jean-Michel Hervouet