I'm thinking I should probably file a bug report for this, since I can't seem to find a similar issue already in the repository. But it's kind of a funny story on its own, in a sad sort of way.
Basically I decided to flood the ocean with magma. A very dwarvenly plan, yes? To this end I located a volcano close to the ocean shore and started a fortress there. My dwarves labored for many years building an enormous magma reservoir, along with a magma-safe pump system to fill it.
Their toils were not without tragedy. About halfway through I realized it had been a mistake to build my main hall right over the caldera on a map where it rains all the time. Dorfs would go out in the rain and then return through the main hall for a drink, whereupon their flesh would melt off and they would bleed to death. I think I lost about sixty souls this way. Then, when the mighty apparatus of
Project: Fuck the Ocean was nearing completion, a fire-breathing she-dragon appeared and proceeded to horribly rape the entire fort, slaughtering about fifty of my hopelessly untrained militia (and biting a couple of babies in half) before a lucky stroke with an axe took off her head. Then, as if that weren't enough, I was attacked by wild horses who kicked several dwarven children to death.
So it was a long, hard slog, and I just barely recovered from tantrum spirals on more than one occasion. I was very glad to finally top off the magma reservoir and put the last gear assemblies in place.
Now, my plan all along had been to build the reservoir and the pumps, place a few levers controlling the whole thing, and then abandon the fort and return to it in adventure mode. In this fashion the magma would be allowed to flow into parts of the ocean which were beyond my initial embark rectangle. (The volcano and the ocean shore were riiiight next to the edge of the local region, unfortunately, so I couldn't expand my embark rectangle in that direction.) So I abandoned the fort and undertook the journey to find it and pull the doomsday lever.
Imagine my horror when I found my way to the reservoir, pulled the lever to activate the pumps, and was greeted by a gushing torrent of nothing but cool, clean,
disgustingly wholesome water.What the hell?!?
Closer inspection revealed that not
all the magma was gone -- just the stuff that had been in "outside" tiles. The reservoir had been partly dug back into a hillside, and the subterranean magma was still there. It had formed an obsidian barrier at the interface. So, apparently, when you abandon and then return to a fort, any magma that is outside gets turned into water.
I checked it in fortress mode too -- I did a Reclaim and the same exact thing happened. Seems like a bug to me, but maybe there is some reason or underlying cause for it? Anyway, it's frustrating. All that effort, all that horrible, horrible
Fun, and with no end result except mass slaughter and chaos! ...Well. I guess when you put it that way, at least it wasn't a complete waste...
Has anybody else run into this?