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[SeekerDarksteel]

Anyone else have water appear without a source in .05?  Ive had a massive amount of water appear at the bottom of a drainage pipe twice now since starting to use .05.  (The pipe was for a water trap, but the trap did not fire so it couldn't have been the source).

Ive submitted a bug in the tracker for it, but I also figured I'd ask if anyone else had noticed anything weird.  Both times its happened its been immediately preceded by around 30-40 seconds of the game being locked up.

[Urist Imiknorris]

Aquifer?

[SeekerDarksteel]

Nope.  This fort has been around 8 years, the drainage pit for 4 of them or so.  I do think I turned off aquifers for worldgen when i worldgenned in .03, but it only happens in this one drainage pit, and only since starting .05.

[Absentia]

The only non-silly non-bug explanation I can think of is if the pipe is intentionally or accidentally connected to some other water source that suddenly became pressurized. But since I imagine you'd notice if that were the case, it sounds like a bug.

Unless you're on a beach, in which case it was a wave.

[se5a]

it's not part of a murky pool is it?

[SeekerDarksteel]

No beach, so its not a wave.  Also not a murky pool. 

 The pipe has two connections, one at the top to drain the area that the trap floods (which isn't where the water is entering because that area isn't getting flooded), and one at the bottom which leads out the side of a cliff beneath a waterfall.  I imagine that, theoretically, if something screwy were going on with the waterfall maybe a ton of water built up at the bottom of the waterfall and fed back into the drainage area.   There's another path which opens up at the bottom of the cliff below the path used for the drainage pit, and that path floods a little bit (maybe 10x3 tiles).  But if all of a sudden there were like 10 Z-levels of water at the bottom of the waterfall you'd think that the lower path would flood before the path for the drainage pit.

[mission0]

A picture would be useful.

[Spider]

should the water have drained off the edge of the map? if so maybe the edge of the map has become a watersource like in the caverns where a body of water touches the edge.

[SeekerDarksteel]

There's an album of the drainage shaft here:  http://seekerdarksteel.imgur.com/OCDL5

[bluefox]

There's an album of the drainage shaft here:  http://seekerdarksteel.imgur.com/OCDL5

Hmmm. From your screenshots, I can posit a side-view of this.

T = trap
G = grate
~ = water
| = Wall
f = fishing platform

Code: [Select]

TTTT
GGGG
~~~~~~~~~~~~~
||||||||||||~
||||||||||||~
||||||||||||~
||||||||||||~
|||||||||||f~
||||||||||||~~~~~

If that's how you set it up, then I think there's some splash from the river. Water levels around waterfalls are ... tricky. I've set myself up for much fun by digging out above a river behind a waterfall, only to have the inside tiles coated in at least 4/7 water.

There's another path which opens up at the bottom of the cliff below the path used for the drainage pit, and that path floods a little bit (maybe 10x3 tiles).  But if all of a sudden there were like 10 Z-levels of water at the bottom of the waterfall you'd think that the lower path would flood before the path for the drainage pit.

That depends on positioning.

I forget where the thread was, but water flow in DF is partially pressure-based, but also happens in order.

For example: in real life, water attempting to seek it's own level goes from this

Code: [Select]

|||||||||||||||||||||
~~~||     |||||     |
~~~||     |||||     |
~~~~~~~~~~~~~~~~~~~~~~~


to this:

Code: [Select]

|||||||||||||||||||||
~~~||     |||||     |
~~~||~~~~~|||||~~~~~|
~~~~~~~~~~~~~~~~~~~~~~~

to this:

Code: [Select]

|||||||||||||||||||||
~~~||~~~~~|||||~~~~~|
~~~||~~~~~|||||~~~~~|
~~~~~~~~~~~~~~~~~~~~~~~

That's not how it works in DF. Water seeking its own level in DF goes from this:

Code: [Select]

|||||||||||||||||||||
~~~||     |||||     |
~~~||     |||||     |
~~~~~~~~~~~~~~~~~~~~~~~

to this:

Code: [Select]

|||||||||||||||||||||
~~~||~~~~~|||||     |
~~~||~~~~~|||||     |
~~~~~~~~~~~~~~~~~~~~~~~

to this:

Code: [Select]

|||||||||||||||||||||
~~~||~~~~~|||||~~~~~|
~~~||~~~~~|||||~~~~~|
~~~~~~~~~~~~~~~~~~~~~~~

Same general effect, but not the one we expect from everyday life.

As to why it's only started now, in 31.05, and not previously? Not sure.

Of course, I could be completely off my rocker, that's not your problem at all, and I've just made an incredibly long and complex post for nothing.

Ah, well.

[SeekerDarksteel]

Note that it's not the fishing platform that's flooding.  It's the grates and drainage from the grates that's flooding, and flooding up to 7/7 instantaneously.  Yes, the fishing platform does get a few tiles of water occasionally, but nothing like the drainage path.  Let me modify your side-view a bit:

Code: [Select]

~~~~~~~~~~~~~      -river (natural waterfall)     
||||||||||||~
~~~~~~~~~~~~~      - waterfall (drainage from indoor waterfall which is operating fine)
||||||||||||~
TTTT||||||  ~
GGGG||||||  ~
............~     -flooding drainage path
||||||||||||~
||||||||||||~
||||||||||||~
||||||||||||~
|||||||||||f~
||||||||||||~~~~~

It's the '.....' path which is going from no water to filled to 7/7 instantaneously, enough to actually go up one more level.  Literally 30 seconds before those screenshots that drainage path was dry as a bone.  Then 30 seconds of lag and the thing is filled to the brim.

[bluefox]

Aha, much clearer now. I've never seen that happen before. If the waterfall is falling down a sheer wall, the most I've seen is mist behind the falls, sometimes water as high as 4/7, but nothing on the scale you're talking about.

It sounds like a bug in the water flow simulation, though I didn't think version 31.05 touched that at all. It would explain your lag spikes - i get a huge spike on my current map when water unfreezes after winter, when all the flow paths have to be calculated. I can't imagine doing that every minute!

And did you mean to show that there's no wall for two z-levels above the drain? Could that screw up water flow at all? I'll need to embark on a waterfall map and try to replicate your results.

I wonder what would happen if you (b)uilt a series of fortifications behind the waterfall?

Code: [Select]

~~~~~~~~~~~~~      -river (natural waterfall)     
||||||||||||~
~~~~~~~~~~~~~      - waterfall
||||||||||||~
TTTT||||||||~
GGGG||||||||~      - empy space behind waterfall? Fill this in!
...........F~     - drainage path, now with fortifications
||||||||||||~
||||||||||||~
||||||||||||~
||||||||||||~
|||||||||||f~
||||||||||||~~~~~

Theoretically, the water would still be able to path, but not *splash*, and thus the drain would only go one way. Only a theory, though; not sure if it will work.

[SeekerDarksteel]

The drainage path is only one z level.  I just didn't throw in enough '|'s. 

I'm guessing it's some kind of glitch with pressure/flow, where somehow the water manages to hit the edge and start piling up, getting forced back up the drainage path.  Unfortunately I can't do any testing really because of how rare it occurs.  Hopefully I can catch it again and roll back to the last autosave so I can replicate it reliably.

The only other thing I can think of is that something really screwy is going on with the strainer, because that's the only level that fills other than the drainage path itself.  So either the water is being produced there out of thin air, or its backing up the drainage pipe from the waterfall and happens to just reach the strainer.

[Pistolero]

Code: [Select]

~~~~~~~~~~~~~      -river (natural waterfall)     
||||||||||||~
~~~~~~~~~~~~~      - waterfall (drainage from indoor waterfall which is operating fine)
||||||||||||~
TTTT||||||  ~
GGGG||||||  ~
............~     -flooding drainage path
|||||||||||.~
|||||||||||.~
||||||||||||~
||||||||||||~
|||||||||||f~
||||||||||||~~~~~

Surely this would fix it? At least it would confirm something screwy is going on if not.