Hi Riadh,
This option is not on the TODO list.
I'd have to think about this for a bit.
The current channel mesher is simple in that it always has a constant number of nodes across the channel. How would you see that resolved?
Could you come up with a picture (GIS coverage) of your situation and a sketch of how a reasonable mesh might look?
I've had another meshing strategy percolating in the back of my mind for years now that might address this situation. I'll need some incentive to move it forward.
Cheers... Martin