Hi there, long time lurker first time poster. I've been playing DF on and off for a while now and have a pretty good grasp of the basics. I thought I had a good handle on water pressure (despite accidentally flooding my last fortress twice in a row by channeling my moat into a hallway and then into my dining room and living quarters, draining it all back out and then immediately collapsing a section of floor through the other side of the moat and into my stockpiles) but this has me stumped. I'm try to build a drowning chamber in my newest fort, but the water is definitely not behaving as I think it should be.
Pics:
Z-level 0:
Z-level -1:
Z-level -2:
As you can see it's a pretty standard setup: water falls through a hole in -1 to -2, and fills up room. Hatches are opened at -1 and water fills up that room as well, drowning everything in it, then the hatch at the top is opened and the pump empties the drowning chamber back into the river. The water comes in directly above the miasma at Z -2 (it was dug out when the river froze over for the winter, my miner managed to be standing on it when it unfroze and drowned. Those are his pants in the second shot and the miasma is his rotting corpse clogging the pipes). The problem is that the water won't fill up the room on Z -1. I initially thought it may be a thing with hatch covers but after removing one of them (upper right one in screenshot) nothing changed.
Any idea if this a bug or just something really obvious that I'm just not seeing?