Dear fellow beaver enthusiasts!
I just managed to build a 2-z-level-damn in the demo.
However, it was not really useful because once the first z-level dried up the pumps couldn't reach the water on the second z-level.
In a game where building big dams is one of the coolest things to do, I believe the pumps should be able to get water from more z-levels than just one below.
Otherwise, there is not really much of a point of build these huge contraptions, which would be a bummer.
Loved the game flow otherwise!
Side view of the damn:
x = Damn
w = Water