There is no ice below the first layer of rock, thus "keeping it" under a rock ceiling isn't really an option. The only way to melt it is to pump magma just under the first rock floor, melting the ice above without melting the floor. It freezes before ever flowing more than 1 space. It doesn't matter what the reservoir is made from; the water can't ever leave the squares directly above the magma heating it. The only option turned out to be dropping some ice through multiple layers of stone floor to cause a cave-in without getting the icicle bug or missing floor bug. However, I made use of our magma-melted area to create a farm, just in time to avoid starvation and effectual prohibition. So everything worked out well, despite a "Plan B" being necessary.
Kol "The Architect"
Spring, 202
Well, it's time for an election, and I'm afraid our charter prohibits me from running for a consecutive term. Well, nothing prevents me from bragging! I became a legend in my own right, with a sprinting speed that puts all other haulers and multitaskers to shame! I traded the heck out of the dwarven caravan, starting with a couple of mechanisms and working my way up to steel armor! Through careful management, I ended up giving them hardly anything by having Unib turn their own trade goods into food to sell back to them! Unfortunately they brought only a little steel armor with their other goods, so in the end a few bits of armor, much-needed wood, silk cloth, and some barrels were the total haul. The caravan left estatic, I put in some nice requests for our next ruler (be sure to buy the cheese and turn it into food again), and laid back a good 30k of forbidden food for fleecing the human caravan in the summer. Food production is set, with extra fields ready when expansion is needed. Related workshops and storerooms can be carved out of the ice around the farms.
If our next ruler is sensible, I hope he will keep some of that silk cloth, wood, and forbidden turtle meat/shell for moods. Since we won't be able to make Obsidian very well, it may be wise to keep what we have out of production until we have appropriate dwarves to make use of it. After all, one good craftsman can do more with 10 obsidian than a cruddy one can do with 10,000. I can't wait to get my hands on a mastercrafted obsidian sword and some steel armor, and do some ice wolf hunting! Going out with anything less would be suicide. I plan to turn my record-keeping duties over to the first appropriate immigrant, as I want them to benefit from the excellent physical fitness! I dabbled in blacksmithing, just to get some pipes and things, and helped Darish put up a nice wall and drawbridge. The second layer rampart with fortifications is nearly ready, in case we should decide to keep watch over the local creature population. I figure magma inside will be our best defense later, although we have to be careful to keep it away from the ice! Our fancy spiraling ramp entrance would easily be ruined.
For Mayor:
I would like to nominate the valiant Glarthir, whose courage may have saved us all, or the cook Unib, whose meals kept us warm and happy, and beguiled much wealth from the traders.
Of course if they don't decide to run I will have to vote for someone else.
Edit:Notes,
1) Dwarves didn't seem to suffer from very short trips outside, even in winter during a snowstorm, but the Wiki does say they will take frostbite damage if they spend extended time periods there. We will have to test this, perhaps by stationing a worthless peasant outside for a couple of game days.
2) Don't ever let the booze run out. That well may be the only one we get
3) The magma area is ready, just channel a hole or two when you want to put in a forge/smelter. Forges on top with bar stockpiles, smelters below with ore stockpiles. No expansion should be necessary; if you can use more than 16 smelters and 12 forges then I'll be a goblin's uncle.
4) Easy expansion areas left behind our first crude meeting hall and crude, narrow barracks. Sparring in there will likely result in injury. All dwarves have their own rooms, although they consist of a single bed in the barracks.
5) Easy wide high-traffic stairwell leading all the way to the bottom with no dangerous up/down stairs, please use this model for consistency and to avoid confusion for following rulers. Branching all workshops, housing and stockpiles for a while off the current main one would be great.
6)Shaft-mining operation is in effect, makes finding veins easy. Beware digging without designating stairs if you continue the model, or you have to go back and build them.
And, the two levers (with notes) are easily accessible in the dining hall, for lack of a formal lever room. That's all the info I have. Up to the new elected ruler what to do with it. Will post a map in a few minutes.