The problem with flow based transportation is that it has somewhat strict upper and lower limits. Any pressure in the system (pretty much gaurrenteed when water height = 7) will both drown dwarves and stop flow since the water will then teleport. And I'm not certain, but I think to move a dwarf you need some pretty high water, something like 4 or 5 would be my guess. So if you were able to modulate the water released into the tunnels between those 2 levels while maintaining a flow in the direction you want at all times, it may work. It goes wtihout saying that would be a pretty major challenge, since merely shutting off the intake when it reaches a certain level would make the flow more random. Alternatively, you may be able to repurpose a river to do all the hard work for you.
The best system I can figure would be something like so, from a top down view:
WDWWWWWWWDW
I______PG_W
WPWWWWWWWWW
WDWWWWWWWWW
where W = wall, I = water in, G=grate for water out _ = empty floor D = door P = pressure plate
When the dwarf, walking from south to north triggers the pressure plate, the two doors on the left side close, and water is rapidly let in through I. This would push the dwarf down the hall, over the second pressure plate and to the grate. The second pressure plate would stop the water from coming in as well as opening the door on the right. Your traumatized dwarf is now free to leave the system. Or not, depending on whether you built it right.
Another pressure plate could be used to reset the system, as could a lever or other device. It negates most of the problem of maintaining flow, since the system starts and ends fast enough that water height wouldn't be too much of a problem. It will also cooperate moderately with pathfinding if you make a path parallel to the water path, as a dwarf wanting to go to the place to which the water takes them will try to wall through the two leftmost doors.