Now I am
seriously OT:
It could, but if you put it just under the surface a bit, say - beneath the spray (or the waterfall), it would likely fail in the off position if you got a
lot of ice. As long as the pump kept working, it should still fill to that level. But, again, as long as the pump was still working, it might again thaw the ice under the water flow. If the pump was
not working, the problem is some less serious, I would guess.
If you want major ice protection, you could put it deep enough (6"?) to prevent freezing, but that, too, could conceivably re-freeze at the lower level...
(Credit posted for the previous $0.02)
The Other Steve