First, some background.
Vucarasiz Thatthil, or Urnflashes of Autumn, is situated in a peculiar biome including aquifers, a river, freeze during winter and part of autumn and spring, and half a haunted influence.
I had first intended to make the aboveground part of the fortress completely out of rock salt, but the very impressive amounts of ice I could very easily gather come winter excited me, and therefore, I instead decided to go for a half-rock salt, half-ice look. This way, Vucarasiz Thatthil gives off the very nice feeling it had been founded eons ago, but the harsh weather turned it into ruins, and walls of hard snow and ice formed over the leftover bricks. A relic from the ages, reclaimed by courageous dwarfs, who put all their energy in carving labyrinthine fortifications out of the ice, giving all the more power to the flying bolts, and a roof... cough, sorry, I got carried away.
So. Now, some facts.
Fact: I like playing with water very much, and started making a pump stack next to the river for future use, when I would figure out what to do with this.
Fact: the terrain is quite mountain-y.
Fact: pumps were already linked to a power source when I started building the stack, figuring that if any changes were to be made, I'd just have to wait for the cold season to stop the whole thing.
Fact: I forgot to build one tiny wall before building a pump, 5 z-levels above the ground, near the fort. Whoops.
Fact: pumps are damn efficient, and a non-negligible part of the map is now flooded and/or covered in mud. Whoops².
Fact: the cold season came before I bothered to stop the infernal device from the power source, as the fountain washed away all fools desiring to do anything around there.
Fact: did you know that floodable constructions (stairs, fortifications) can be encased in ice and effectively "destroyed"?
End result: there are many intricate forms made out of ice around half my fortress. And I have to dig out some stairs and many fortifications, THEN build them back.
But it's very pretty. Now, I know what to do with the water: controlled waterfalls/flows that give out a more authentic feel to the fortress in winter.
Ironically, a kitten had fallen in the river, and it only survived by standing the best it could right under the pump. Now, everything is frozen, but the kitten isn't encased in ice because its tile was the only one in the riverbed that isn't frozen solid. Better job at surviving than the guys who fell and drowned.
Question: if I smooth/engrave the cast ice walls (as opposed to the artificial, hand-built ones), will they still be there when the temperature rises again?