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[TigerPlushie]

Before switching to Dig Deeper i was working on a rather successful, calm fort. It featured a brook and a chasm, which directly made me thing "oi! Infinite flowing water supply!" Since flowing water is never considered nasty (a think i remember from my cistern in an older fort) i took this opportunity to make a pipe from the brook to the chasm, eventually supplying water for my farm, moat and wells. And all was well...
Then came winter!
I eventually forgot to check the climate, so that the water pouring into the chasm froze, sealing the drain. I was pretty nervous at that point. The water filled a cave beneath the drain, but it was soon to be frozen as well. At that point i expected my many wells and moat to pour over and flood the place, since the water intake didn't freeze.
But as time went by nothing happened. No spills, no flood, nothing.

As to the mechanics: I tapped a brook tile, let the water fall down a few tiles where it flew straight to the chasm, regulating only with floodgates. Also a thing i noticed was, that the water streaming through the dug out pipe was not animated until it touched the chasm for the first time. After that it looked like a river does when flowing, making me wonder, if that particular flow was maybe tagged as "consistent" or with a solid drain or whatever.

In the end, i am just wondering why nothing has happened. I still got the save, so I might check on it again.

[Elvin]

The same thing happens when you put a dam in a river. The water just stops, and doesn't flood its banks or anything.

[DeathOfRats]

The way pressure works in DF, water never flows above its original level (unless you pump it up. Pumps reset pressure). This means that, as long as your wells, moat, and whatever were at the same level or higher than the river banks, you're safe. If they'd been lower, you might have had a flood much earlier, even with the chasm.

Water in DF tends to make very smooth gradients, unlike in real life, which means that eventually you'd find yourself with a 7/7 flow under the well, no matter its distance to the chasm. At that point, it might start overflowing if the origin point of the water is higher than the well.

[TigerPlushie]

Well, in my new dug deeper fort, things are a little more as i had expected them.

The water drops down a few levels, runs to my well/watering hole, then to my irrigation, where there is either the irrigation intake to water the field or a bypass, that directly leads to a chasm. if the intake (and drain) or the bypass is open everything is alright, but if they are both closed, the well overflows. I learnt this the practical way. I'd say hard, but nothing bad happened.

Still, i wonder why it worked so well on the previous fort, because i am pretty certain, that the water dropped a few Zs there as well

[Puck]

Isn't there something with water raising one z level below the original level if you do something to it? Cant remember what, tho.

Also, in your first fort, maybe the water had to travel diagonally somewhere, I believe that resets pressure too.

[Neruz]

Isn't there something with water raising one z level below the original level if you do something to it? Cant remember what, tho.

Also, in your first fort, maybe the water had to travel diagonally somewhere, I believe that resets pressure too.

Correct, water pressure goes to original z level-1 (pumps reset pressure.)

So if you have water coming from Z level 16, water pressure will push any water from that source to Z level 15, and no higher. If you pump the water through a pump on Z level 5, then any water going through that pump will only go to Z level 4.

[Hellcar]

Water travelling diagonally will also lose it's 'pressure'.
ie

Code: [Select]

###
~~###
##~~~
 ####


[Quietust]

Isn't there something with water raising one z level below the original level if you do something to it? Cant remember what, tho.

Also, in your first fort, maybe the water had to travel diagonally somewhere, I believe that resets pressure too.

Correct, water pressure goes to original z level-1 (pumps reset pressure.)

So if you have water coming from Z level 16, water pressure will push any water from that source to Z level 15, and no higher. If you pump the water through a pump on Z level 5, then any water going through that pump will only go to Z level 4.

Incorrect - while free-flowing water on Z-level 16 will only fall and rise back to Z-level 15, water pumped onto Z-level 5 will fall and rise back to the same Z-level 5.

[DeathOfRats]

Isn't there something with water raising one z level below the original level if you do something to it? Cant remember what, tho.

Also, in your first fort, maybe the water had to travel diagonally somewhere, I believe that resets pressure too.

Correct, water pressure goes to original z level-1 (pumps reset pressure.)

So if you have water coming from Z level 16, water pressure will push any water from that source to Z level 15, and no higher. If you pump the water through a pump on Z level 5, then any water going through that pump will only go to Z level 4.

Incorrect - while free-flowing water on Z-level 16 will only fall and rise back to Z-level 15, water pumped onto Z-level 5 will fall and rise back to the same Z-level 5.

Not exactly correct, either. It'll rise back to level 5 on the side the pump is.

Let's see if I can illustrate this. Imagine we have two chutes connected by a passage, as in the diagram below:

Code: [Select]

######
  #
# # ##
#   ##
######

Now we add a pump on one of them, which pumps water to that chute. The water will rise on the other chute as well, up to one z-level below the pump, resulting on this:

Code: [Select]

######
  #w<<
#w#w##
#www##
######


[kaypy]

Now we add a pump on one of them, which pumps water to that chute. The water will rise on the other chute as well, up to one z-level below the same z-level as the pump, resulting in this:

Code: [Select]

######
~~#~%%
#~#~##
#~~~##
######


Fixed that for ya

http://mkv25.net/dfma/movie-1595-screwpumpoutputpressure

[DeathOfRats]

Well, it's good I got corrected before I flooded my fortress, then 

Also, I'll have to keep in mind what the symbols for pumps, etc, are. I usually play with a tileset, so I had to improvise. I found the >> and << work pretty well at least for indicating pumping direction.

[kaypy]

Well, it's good I got corrected before I flooded my fortress, then 

8-)

Pumps seem to use their own pressure mechanism that doesnt have more than coincidental resemblance to the regular pressure system- which is why they wind up giving magma 'pressure' too...

Also, I'll have to keep in mind what the symbols for pumps, etc, are. I usually play with a tileset, so I had to improvise. I found the >> and << work pretty well at least for indicating pumping direction.

We knew what you meant, I just get carried away with the symbols. At least I wasn't coloring them in this time...