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[Maestro Ugo]

Okay, I have a few general questions about water and fluid in DF. Keep in mind that I have never actually dabbled in water working before. I have abandoned this idea for my current fort as my -1z level is too dug up to support a moat, but would like to know for future uses.

I have a biome without any running water, just a bunch of murky pools at the ground level. I would like to build a closed system that would pump fresh water and provide for a moat, a waterfall and hospital use. I envisioned it something like this (actual levels might be a bit off):



a - murky pool (here only one is depicted, but I intended to channel from 4 different pools).
b - some sort of vertical chasm for water to flow through
c1 - one time cistern
c2 - perpetual cistern
d - a stack of pumps one on top of each other
e - moat

basically, my plan was to channel water from various murky pools (one at a time using floodgates) into one big cistern. Than pump the water up a few z level to fill the moat. Water would than be channeled from the moat to another cistern (c2) and on the way provide a waterfall in my dining hall and fresh water in my hospital. From c2 it would than be again pumped into the moat, closing the circle. The dark line in d designates where it would be cut of after initial pumping. This would in theory provide a closed system of fresh water running around my fort.

I want to ask, would this be doable? If so, how could I calculate how much water would I need for this closed system to work? Also, what is the best way to channel water down? Up-down stairs? Ramps?

Also, is it possible to dig a hole in the ground through multiple levels? How would one go about doing that? Would I need acces hallways at every level, or is there a different way?

Thanks for any input.

[chaosgear]

I've never done anything with pumps on this level, but I do know enough about water flow.

It seems doable. Water flows through up/down staircases just fine. You could just channel straight down, but you would have to have some way for your miners to get out of the pit.I would build access tunnels throughout the system, though, just to be safe. You can never be too careful with large volumes of water.

Stagnant water is converted into fresh water whenever it travels through a pump. All you'd have to do is make sure that the stagnant and fresh water never meet, or it will instantly convert all the fresh into stagnant.
And you need to take powering the pumps into account.

[Buhamut]

All you'd have to do is make sure that the stagnant and fresh water never meet, or it will instantly convert all the fresh into stagnant.

No longer true. One of the last patches made fresh water purify stagnant water. This change was due to murky pools corrupting your rivers and making the entire thing eventually turn stagnant.

[Mr S]

More specifically, stagnant water will not pass through wall tiles and spread through flow tiles.  Contamination is another matter entirely.  Were you to open up a channel from a river (flow tiles) into a murky pool (stagnant) it would previously have allowed the stagnation to creep through the flow tiles (with the channeling not being necessary if they shared a wall).  It appears the reverse is now true, although I cannot confirm that.  I can say that Toady specifically mentioned stagnation not creeping into flow tiles any more.

Also, it appears that a cistern with natural walls will become stagnant in certain circumstances, so this may need a bit of research to find out if you need to wall them with built materials, smooth natural walls, or just ensure constant flow.  I'm not so sure about this aspect without reading a bit on cisterns.

Another thing to take into consideration is evaporation.  The water won't just move like a wave and pick up its own tail after it when you open the floodgates from the murky pools into the cistern.  Calculate 1/7 loss of water for every tile of the source and transit areas as well as roughly 10% of the tiles in the destination area (gets skewed a bit for very large areas with slow fill rates).

Last but not least, add in safety measures in case of cistern over filling.  Channeling out an area to the map edge, then carving fortifications in the last, unminable tile will make for an "over flow" drain.  So, based on the above, I'd calculate each of the listed cisterns to need 20% more from the gross supply to satisfy the finished project, as well as adding safeties.  That's always a good idea to any gravity draining/filling system that is "open to atmosphere" so to speak.  Or maybe that's the engineer in me over analyzing things.

[thegoatgod_pan]

I wouldn't use pools, they will drain and provide all sorts of routes into your base for titans, which will be a pain to deal with once they are tearing up your pump stack from under the water. Also too little water there.

However if you use an aquifer or a cavern lake, this should be eminently doable. Just remember to put a few grates around only reachable from below so nothing can get at them.

[doublestrafe]

It can be really helpful to imagine the water not as water but as, oh, maybe that green slime they used to have on Nickelodeon. It doesn't so much flow as ooze, and it dries up around the edges. If you need water to get from point A to point B 50 tiles away, and you've only got maybe a 10x10 murky pool, you're probably better off designating a pond or setting up minecarts than expecting it to flow down a channel. You can push water anywhere if there's enough of it to fill a channel with a pump behind it, but with smaller amounts your options are really limited.

[zazq]

Be sure to un-murkypool all tiles in your moat because they will evaporate your water right quick if your embark gets hot enough.  Also, while wells use up almost no water at all, a waterfall will result in water loss, and so you'll need to replenish your supplies.  I see no reason why your various uses for water need to be connected, and i can see now a titan going swimming in your moat and coming out the waterfall in your dining room.  Not to mention a vampire falling into your moat or something would infect your waterfall and well. (wouldn't THAT be fun).  So keep em separate.

1) moat.  A dry channel is better protection than a water moat.  just make a big ditch around your place.  save your limited water for important things.

2) well.  I usually have a water source somewhere far away from my hospital, then dig a 2z level deep hole in the hospital, stick a well on it, and have dwarves fill the well with buckets of water from the water source.  if there is a well on both ends this may or may not generate extra water.  I know that it takes 7 buckets of water to fill a square, and i'm also pretty sure that it takes 10 fillings of a bucket from a well to use up 1/7 of a square.  Anyway, the hospital well doesn't see that much use and so hand filling it should be fine.

3) waterfall.  Everypony wants these and they are hard to build, hard to keep running and they cause lag.  Anyway, you'll need a reactor to power it and a significant area made of floor grates so that it is unlikely water will get on the ground and dry up.  Dwarves getting wet doesn't actually use up water, so you're safe there, but hitting them with falling water is dangerous to unarmored dwarves.  I'd recommend having the water fall on a tile and restrict traffic there to keep dwarves off it.  Then the mist flys outward from the tile a few squares and falls down though the grates into a cistern where it is then pumped back up.  You'll still lose water though due to random extra far mist travel and the 1 tile it lands on.  Collecting rain water is hard.  You'd have much better luck finding water in your caverns. 

...

Water travels down up/down stairs just fine, and those are most convenient for dwarves.  Digging empty holes is a trick to learn too.  if you want a 5x5 hole 10z levels deep, first dig the whole thing out of up down stairs.  This will be make caveins unlikely.  Then, starting at the top, designate each level to be channeled.  The miners will do this from the level below where you designated and result in nothing left on the disignated level.  Then go down 1 level and designate for channeling and repeat.  Smooth each level if you want it look pretty and consider adding windows so dwarves can look in and see the fishes/goblins going by.   

[kingubu]

All good stuff.  Wanted to point out that water flows downstairs, but you can't pump from a staircase.  You'll need a channel.

Murky pools refill in the rain.  Build a wall around it, and a floodgate can be used to dump more water in the system every so often if it's a rainy area.  If you're worried about flying BUILDINGDESTROYERs, you could use a raised bridge instead of a floodgate.

I've filled cisterns many times the size of the murky pool using this system.

[AutomataKittay]

Glancing at your diagram, I'd say it could work, assuming you don't have too much room for water to evaporate off. Using murky pools as major water sources aren't really practical outside of areas that rains a lot, though.

You sounds unsure of what you're doing, so this thread might help, or at least the diagram in it http://www.bay12forums.com/smf/index.php?topic=32453.0
It's for older version, yes, but pressure algothirm haven't changed that I've seen, other than there being more 'push'.

As long as there're nothing for water to spill in below the murky pool level, you should be fine. Though you might want to put a special pump one level above so you can feed a well, since some things can swim into water and jump out. I've lost a few fortesses that way

Putting a grate on pump intake from the murky pools will do the trick too for it not getting eaten up!

[Berossus]

All you'd have to do is make sure that the stagnant and fresh water never meet, or it will instantly convert all the fresh into stagnant.

No longer true. One of the last patches made fresh water purify stagnant water. This change was due to murky pools corrupting your rivers and making the entire thing eventually turn stagnant.

Im in no way an expert or even close, but i can say that a (horizontal) donut of water with a pump in it will only produce stagnant water, because i tried that setup for my hospital.

XXXXXXXX
XwwwwwX
XCPPXXXX

X= mined tile with water from a murky pool (feeding from the mid left)
w= wall
C= channel
P= pump

This never made fresh water for me.

[kingubu]

On second look, I just realized there's a chance water pressure could flood out your pump stack.  Woops.

Once (c1) is full, water falling onto it from (a) will generate pressure that can raise the water into (d)

You will need a diagonal pressure regulator in (c1).  Details here: http://dwarffortresswiki.org/index.php/DF2012:Pressure under Neutralizing Pressure