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[Mrok Girl]

Hi!

I want to build a megaproject where there's a cistern of water above ground that is supplied by pumps pumping water from the underground water layer, and the water then falls down gently in a circular waterfall down through all the layers back to the underground water layer. Here's a helpful (?) image to (hopefully) illustrate what I have in mind. This shows the view from the side, through the Z levels:

Spoiler (click to show/hide)

So how do I do it without flooding the whole fortress (at least not immediately), but with the maximum soothing mist spreading through the layers? I tried to read the wiki articles about the water pressure etc but they are long and complicated :/ I'm hoping someone who's experienced in such shenanigans can give me some practical advice.

Thanks in advance!

[Dorsidwarf]

I think you'll need a lot of grates to maximise mist and minimise dwarves being dragged hundreds of feet of vertical pipe to their deaths

[Mrok Girl]

I think you'll need a lot of grates to maximise mist and minimise dwarves being dragged hundreds of feet of vertical pipe to their deaths

Yes, I had great success with grates in the past I'm just worried that the water will fall faster than it can redistribute itself in the underground water layer, and the whole fort will be flooded. Or is that a baseless worry?

[Sver]

IIRC, water does not push creatures/items through floor grates - only the vertican ones (the same applies to bars and fortifications). Kruggsmash had something like this in his Monsterkiller fort, and the only "casualities" were caravan wagons attempting to path through the waterfall. I don't remember which episode that was exactly, but there didn't seem to be too much problem with flooding, so simple floor drains should be enough, as long as the water has somewhere to go, like an aquifer or a river. Regarding the disposal of water into a cavern, here's an excerpt from the wiki:

One [way] is to channel your excess water into a dry cavern that is open to the map edge, as the water will flow out (depending on slopes, original water level and such). Be careful if you dump the water into an underground lake, as such lakes have some sort of equilibrium built into them, and your excess water may cause them to flood. The other, probably easier method, is to mine to the map edge (since you cannot mine the map edge itself, just up to it), then smooth the edge and then carve fortifications into it. Water will flow through the fortifications and off the edge of the map. Make sure your exit flow is equal to or, for safety, greater than your input.

Also, note that mist freely travels through grates/bars/fortifications and seems to spread between z-levels too, so your dwarves don't necessarily have to be at the exact same spot where it generates to feel it.

[Mrok Girl]

IIRC, water does not push creatures/items through floor grates - only the vertican ones (the same applies to bars and fortifications). Kruggsmash had something like this in his Monsterkiller fort, and the only "casualities" were caravan wagons attempting to path through the waterfall. I don't remember which episode that was exactly, but there didn't seem to be too much problem with flooding, so simple floor drains should be enough, as long as the water has somewhere to go, like an aquifer or a river. Regarding the disposal of water into a cavern, here's an excerpt from the wiki:

One [way] is to channel your excess water into a dry cavern that is open to the map edge, as the water will flow out (depending on slopes, original water level and such). Be careful if you dump the water into an underground lake, as such lakes have some sort of equilibrium built into them, and your excess water may cause them to flood. The other, probably easier method, is to mine to the map edge (since you cannot mine the map edge itself, just up to it), then smooth the edge and then carve fortifications into it. Water will flow through the fortifications and off the edge of the map. Make sure your exit flow is equal to or, for safety, greater than your input.

Also, note that mist freely travels through grates/bars/fortifications and seems to spread between z-levels too, so your dwarves don't necessarily have to be at the exact same spot where it generates to feel it.

Right, so if I dump the water to the underground water layer, assuming that the water flows freely from the edges of the map rather than that it's contained in a lake, then I should be fine? Otherwise designate one of the caverns as the water dumping ground so I can flood it?

[Sver]

Not sure about the map border lakes - the wiki got me puzzled there. I assume they are safe, because I've had an experience of redirecting a river into one.

In any case, it would be good to have a plug floodgate for the whole system, somewhere before it starts pouring into your living space - preferably even before it reaches the cistern. Just as a failsafe.

[Mrok Girl]

Yes, I was thinking about that too. Those tunnels leading from the little towers to the cistern - I think that's where I'll put the floodgates.

[anewaname]

Your underground water layer need to disperse the water off the edge of the map at least as fast as it arrives, or it will fill up slowly. The water flows off at about the rate water flows into an empty tile, so you can disperse about 3/7 water per "edge of the map" fortification.

Test those floodgates before putting water behind them.

[PatrikLundell]

If the "underground water layer" is an aquifer it's capable of absorbing unlimited amounts of water, but it still has to fall before it flows off to the sides. It's also possible to use Deployable Drains to get rid of water (minecart on a track stop dumping into a wall while all access except from above is blocked: the water level is kept at 5/7).

Note, however, that if you want your dorfs to pass through the curtain of water you have to keep the flow down. I've tried a Dwarf Washer, and my initial designs caused the dorfs to cancel the pathing because there was too much water (and some minor mud deposits were made before I turned it off). I did get help from the forum (Loci, I think) to get a working design which I've used in my later fortresses (and the buggers only complain about being rained upon, while being washed by water is apparently a pleasant experience due to the mist).

[Mrok Girl]

Those are all good points. So floodgates with levers definitely, and if I'm going to use fortifications to dump the water off the map, it should be a lot of them. Gotcha.

[gchristopher]

I think this won't be too bad, as long as you incorporate an extra Z-level or two at the top of your drain area. What you're describing is a normal waterfall-mist generator, with the main difference being you want many tiles of falling water arranged in a circle. The solution will be to take something that works for one tile and scale it up for the whole design.

The key feature that will make your life easier is: pressurized water instantly teleports any distance regardless of a narrow bottleneck.

So, water will fall from the cistern, down through the area you want the waterfall curtain, and for each tile, eventually fall through the bottom-most grate. Below this grate, make sure there is at least 1 z-level (I prefer to leave 2), before whatever drain assembly you build. Assuming you don't have convenient aquifer tiles (or portable minecart drains) to sink the water, there will be some horizontal passageway full of water between your waterfall and wherever the water drains.

As long as you have that extra vertical buffer space above the horizontal drain area, any water that piles up there (under the bottom grate), will instantly teleport to the first available drain outflow. (Like the edge of the map.) How narrow or long the passageway between the bottom of your waterfall shouldn't matter, as long as the total drain capacity exceeds the rate of your waterfalls.

To make it easier, I suggest depressurizing the water at the top of the waterfall by putting a diagonal between the cistern and where water starts to fall.

[gchristopher]

I did get help from the forum (Loci, I think) to get a working design which I've used in my later fortresses (and the buggers only complain about being rained upon, while being washed by water is apparently a pleasant experience due to the mist).

What did that end up looking like? Did you get a perfect 1-tile washer? (I assume perfect means has >= 1 water present on the tile with no dry gaps long enough for anything to path through, and never >3 water causing path cancellation?)

The last time I tried that, I never found a way around the mist occasionally washing dwarves on tiles adjacent to the falling water, and so it deposited contaminants on the adjacent tile, eventually husking/thralling animals that walked through. (Because any embark without multiple thralling dust/ooze evil cloud combinations is no fun.)

[PatrikLundell]

I didn't get any cancellation spam, so it was never more than 3/7 water, and I believe it was occasionally 0/7. The construction drops water on a 2*2 passage with diagonal access, but I'm not sure if contaminants were deposited on the access tiles.

The entrance level:


WW..WW
W.WW.W
WWggWW
WWggWW
W.WW.W
WW..WW

N/S passage, with 'W' = Wall, '.' = floor, 'g' = floor grate, with the water falling from above on the 4 grates.

I guess it would be possible to have several of these in a passage for a more thorough rinsing.

[Mrok Girl]

To make it easier, I suggest depressurizing the water at the top of the waterfall by putting a diagonal between the cistern and where water starts to fall.

All good points, thank you very much. But I'm not sure how to do this though - and how will that help if the top level is still above the rest of my fort?

I'm currently building my fort and the cistern ended up in a sort of donut shape because I decided that since I want a curtain of water in a circle, it's pointless to have the water in the middle of said circle. Not sure if good idea? I was planning to make this donut 3-4 levels high and then bring water from below on the sides of it, and put diagonals there when it'll enter the donut. But I could build a cylindrical cistern inside the donut hole as it were, and make that diagonally attached to the donut in a few places?

[PatrikLundell]

I think having the storage in around the curtain and depressurize it as well as cutting down the volume that's dropped is a good idea. However, if you actually want to emulate an unbroken circle I think you need an outer access as well.

Something like:

..Wo.W.
.W.oW..
..Wo.W.

where "." is a floor with water, 'W' a wall, and 'o' open space for the curtain of water. Every second tile would be fed from the left and the alternate ones from the right.

Then you'd have to bend the water curtain, which might not be easy to fit in with the diagonal accesses. A possible thought is to try a similar construction on the level above in places, although I'm not completely sure it would help (I haven't tried to visualize it).

As long as the water dropped is drained away properly and doesn't flow out to the side into the fortress you should be fine when it comes to flooding, but I'd definitely make sure the cistern isn't too large and that there's a way to turn off the pumps filling it (in a place which isn't the first one to be flooded in case of an architectural mishap... That way your fortress would be flooded with only a cistern's worth of water, which should evaporate when spread out over a sufficiently large area.