I'm playing 0.34x on a mac with macnewbie (in case it matters) and am relatively new to the game, but I thought I understood that water only moves easily orthagonally and with difficulty diagonally, but not at all through solid stone. I am playing a cliff face with a river outside (not an underground one) about 8 z levels below the cliff. There is a sand layer near the top of the cliff that I dug through. The river (in the portion where I dug) is lined with gneiss and has a nice outside bend where I can easily divert a channel for my well (I did this once before successfully). That whole layer has flooded. I don't know if it happened suddenly or gradually, the first I knew of it was when my miner ceased work due to "dangerous terrain". I had gotten a damp stone warning previously, which I respected, allowing the job to be canceled, though I couldn't see why the stone was damp. I examined the river edge very carefully, stone by stone, and there are no diagonals in contact with the river and no breaches. Then as I flipped up through the levels I noticed the sand layer near the top was blinking the blue "damp stone" warning too, 5 z levels above the river! But that didn't bother me. I figured it was just a weird bug, but I stopped digging there anyway. At that point there was no water in the fort, just some damp stone along the edge. The one thing I did differently this time from when I successfully diverted a river before was I dug the channel up to the containing wall and then left it for a time without smoothing (I had other things I had to take care of).
So, my question is, does the water come directly through porous stone after a sufficient amount of exposure (there were also small veins of fire opal, tetrahedrite and native silver in the area contacting the river)? or is this a bug? I did read something about porosity and aquifers, but I couldn't find anything about water moving *through* stone, just that aquifers are found *in* porous stone. Would smoothing have prevented this fun?