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0002195Dwarf FortressDwarf Mode -- Environmentpublic2010-06-06 18:332017-11-01 14:59
seekerdarksteel 
Loci 
normalmajorrandom
resolvedno change required 
0.31.05 
 
0002195: Water magically appears
Twice since upgrading to 0.31.05, DF seems to lock up for about 30 seconds. A few minutes after the first one and immediately after the second, I noticed a massive amount of water had appeared underground without a source.

The water appeared at the bottom of a drainage pit for a flooding trap, however the trap itself was not activated so the water did not come from that. The bottom of the pit drains out near the base of a large 22 Z-level waterfall. The entire drainage path (about 75x3 tiles) is filled to 7/7, as well as the 5x6 room above it. Additionally, the level right above the waterfall is filled to 7/7 for around 25 tiles near the base of the waterfall. The water eventually completely drains out of the drainage pit.
Can't force it to reproduce. Has happened twice in about 10 hours.
A copy of the save is at http://dffd.wimbli.com/file.php?id=2459 [^]

The drainage pipe in question is just to the left of the entrance to the fort. It's bottom is at z-level -17.
No tags attached.
related to 0001899resolved Toady One Game locks up for 30 min during seasonal temperature shift 
Issue History
2010-06-06 18:33seekerdarksteelNew Issue
2010-06-06 18:41FootkerchiefDescription Updatedbug_revision_view_page.php?rev_id=2946#r2946
2010-06-06 18:41FootkerchiefSteps to Reproduce Updatedbug_revision_view_page.php?rev_id=2948#r2948
2010-06-06 18:42FootkerchiefNote Added: 0007851
2010-06-06 22:32seekerdarksteelNote Added: 0007867
2010-06-06 22:34seekerdarksteelNote Edited: 0007867bug_revision_view_page.php?bugnote_id=0007867#r2950
2010-06-07 00:34RiceMunkNote Added: 0007869
2010-06-07 08:39seekerdarksteelNote Added: 0007875
2010-06-07 09:43FootkerchiefNote Added: 0007878
2010-06-07 09:44FootkerchiefNote Edited: 0007878bug_revision_view_page.php?bugnote_id=0007878#r2956
2010-06-07 11:35seekerdarksteelNote Added: 0007883
2011-03-30 13:39FootkerchiefRelationship addedrelated to 0001899
2017-11-01 14:59LociNote Added: 0036832
2017-11-01 14:59LociStatusnew => resolved
2017-11-01 14:59LociResolutionopen => no change required
2017-11-01 14:59LociAssigned To => Loci

Notes
(0007851)
Footkerchief   
2010-06-06 18:42   
Could there have been ice melting down there?
(0007867)
seekerdarksteel   
2010-06-06 22:32   
(edited on: 2010-06-06 22:34)
Nope. The map doesn't get cold enough to freeze. It's also not an aquifer. I turned off aquifers when I world-genned, and played this map for about 6 years in .03. I just started on .05 and have played around two more years and it's happened twice now. The drainage pit the water is appearing in was there before i switched to .05 as well.

(0007869)
RiceMunk   
2010-06-07 00:34   
One thing I noticed in one of my games was that whenever it starts to rain, all the aboveground ponds on the map (the ones with that "special" muddy pond tile as the base) magically refill completely even if they dry out again very soon afterwards.
Of course if there's a hole in said pond, it will then promptly proceed to empty itself into said hole. Maybe something like this happened to you too?
(0007875)
seekerdarksteel   
2010-06-07 08:39   
No murky pools anywhere near the pipe in question.

One other weird thing is that right outside the cliff face where the drainage pit drains to, there's a like that appears as '.' instead of the normal open space. Using 'k' over it states that it is inside, and shows every other tile which appears as normal open space to be outside. One Z-level up is still inside, and two z-levels up is outside. But there's nothing actually built there, nor has there ever been. (More than two z-levels up it appears normal). Going down z-levels, it continues to state that the tile is inside all the way down to the river, but there's not anything actually built there.
(0007878)
Footkerchief   
2010-06-07 09:43   
(edited on: 2010-06-07 09:44)
Nope. The map doesn't get cold enough to freeze. It's also not an aquifer.

It was speculated in another report (0001562) that water can (buggily) freeze in caves even if there's no clear reason for it to be that cold. We could use empirical confirmation that ice isn't forming on your map -- that 30-second pause certainly sounds like a massive thaw.

(0007883)
seekerdarksteel   
2010-06-07 11:35   
I'll keep an eye out for ice forming as I keep playing, but I haven't seen any ice form yet. The area in question is near enough the main part of my fort that I see it everytime I scroll up or down the main shaft of my fort, so I imagine I would have noticed a bunch of ice forming.

I turned on seasonal autosaves, so hopefully I'll be able to catch it and reproduce it.
(0036832)
Loci   
2017-11-01 14:59   
Freezing temperatures can appear briefly on only part of a map. In this case, it sounds like the outflow river froze for a short time, causing the waterfall to flood into your fortress via pressure-teleportation. Then the ice thawed, lagging your game and drawing your attention to the mysterious flood left behind.

Of course, all that is speculation since the save is no longer available. According to the release notes, Toady did adjust seasonal temperatures (to fix rain bug 0000190) in v0.31.05, so that could explain why parts of your map only started freezing in that particular version.