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[Trotskisaurus]

Hello forum! I apologise for a question that has been done to death i'm sure but i'm not sure I know what the answer is even after reading numerous topics about it.

I'm in the middle of building a fort and I have a few ground rules; I try to obey the laws of physics and possibility as much as possible...in a game based on dwarves and magic. I am looking to have a healthy supply of power with which I can move magma and water to wherever I need it. I can't quite bring myself to build a standard dwarven water reactor and i've been thinking of alternatives.

I've considered making a connection to the brook on the surface and running the water down a series of ramps past waterwheels. I would then be left with lots of water entering my fort but, luckily, I have an underground lake touching the edge of my map so I believe I can filter it through there. I wondered though if there was an alternative? From what i've read water pressure will push the water back to the level in which it entered the fort; does this mean I could push it up to the level of the brook and feed it back into it? Is this how water pressure actually works in real life or is it a quirk of DF?

If I ran water down a series of ramps and under waterwheels in this way would it cause any risk of flowing back into the fort? Could it flow past the waterwheels? How heavy a drain would this be on FPS?

Thanks for any help!

[Maximum Spin]

Is this how water pressure actually works in real life or is it a quirk of DF?

"Sorta". For a more detailed explanation please consult a hydraulics textbook.

If I ran water down a series of ramps and under waterwheels in this way would it cause any risk of flowing back into the fort?

Yes. Make it go through a diagonal gap or something to depressurise it.

[Fleeting Frames]

What you posist is not optimal (due not breaking physics), and when made too wide will not give any power, but it sounds like it could be pretty nice to look at in a visualizer, if it can be given space to breathe and look at.

E: Also, I think the water would drain off map before flooding your fort, unless the fort's in the caverns.

[Trotskisaurus]

Thanks for the replies!

I don't mind it being sub-optimal (though I am worried about the FPS) as long as it seems somewhat more logical than quantum waterwheels.

If I did pierce the brook and filtered the water down through my fort and then at the bottom created a 'chimney' (a one square hole stretching from the bottom level to the original level of the brook) would the water simply bubble up there would would it back up and push its way past the waterwheels and axles into the main body of my fort? I get the impression it'd be the latter and i'd end up with some FUN

[Fleeting Frames]

The latter. U bend's start will not have lower fluid level than end.

Quantum...I'm not sure what you mean. The reactors are perpetual, but can't stack buildings yet. As far as more natural solutions go, there's also channeling brook surface and placing waterwheels there; the brook is already permaflow.

[Saiko Kila]

There is no pressure in DF at all, because there is no air, and both water and solids do not exert pressure on the underlying materials. But some effects of pressure are simulated.

If some water has "pressure", it means that it will try to level with other water tiles connected orthogonally, like in a open U-pipe in real life. If water doesn't have "pressure", it won't try to level.

Water falling downwards creates "pressure", pumped water and water creates "pressure", as well as dammed river or brook (undammed rivers can create "pressure" thanks to falling water, one level below their base level).

"Depressurizer" is a diagonal gap, which slows down flow, but also removes the "pressure". "Presurizer" is one of the mentioned above, often a pump (pump is the only pressurizer working for magma/lava). So you can easily pump the water back into the creek by building a stack of pumps, and you can even pump above the creek, to try to flood the whole map, if you want. One wheel creates enough power for several pumps, that's why it's easy.

If you think that water can flood your fort (falling water certainly can), then just enclose it in tunnels. You can have maintenance doors and bridges for repairs or emergency access.

[Ziusudra]

I wondered though if there was an alternative? From what i've read water pressure will push the water back to the level in which it entered the fort; does this mean I could push it up to the level of the brook and feed it back into it?

No. The brook would fill all the tunnels but there would be no flow under the wheels.

[PatrikLundell]

If you want to play "natural" you should probably place your water wheels in the brook/river, as that is how humans have done it until water turbines started to be used with dams (dams have been used historically, but the water wheels have been on top of the water, not inside tunnels). Of course, humans haven't had that much of building destroyers (apart from marauding enemy armies). Assuming the latitude is suitable, you can also use wind mills, but they have a rather poor performance, where a lot of what is produced is lost through the transmission you need. Some latitudes do not produce any wind at all, while the others are produce one of two levels of low power.

A semi cheaty way to get rid of water is to carve fortifications in the wall, as water will drain through those, even if there logically would be solid rock on the other side. Thus, you can lead water down and then off the map.

[Trotskisaurus]

Thanks for all the replies, it sounds like what I was aiming for wouldn't really work in that case and the only realistic options would be;

1) To place waterwheels in the brook.

2) To create a flow of water from the brook through my fort and draining into the cavern lake.

I think the second option would probably be better, as ideally i'd like to bring Lava to the surface which could only be done if I was able to get power to some depth. If I drain into the cavern lake that should then create flow I would assume? Just as if I carved fortifications into the side of the map?

[Fleeting Frames]

Yep, with the difference that things may wander up unless you use a floor grated U-bend to prevent that.

[Loci]

If I drain into the cavern lake that should then create flow I would assume? Just as if I carved fortifications into the side of the map?

Flow (the in-game status which activates waterwheels) is a very particular thing. Water can have intrinsic flow (like rivers), or it can have temporary flow when two adjacent tiles with differing amounts of liquid average their contents. Ramps are completely unnecessary (water does not accelerate in Dwarf Fortress) and multi-z-level tunnels are counterproductive since stacked water moves via pressure-teleportation which not only doesn't count as "flowing" but also fills the lower levels preventing those tiles from "flowing" as well.

So no, draining into the cavern lake will not automatically create "flow" throughout your complex waterway. Each tile will have flow or not depending on the difference between water levels of it and its neighbors. Further, since liquid levels are quantized into 8 possible values, a long waterway will suffer intermittent flow when multiple equal tiles stack up next to each other. To avoid that problem, your waterway should be kept short, with waterwheels in parallel instead of in series. Or you could just build the waterwheels in the brook and save yourself the headache of trying to understand dwarven hydrodynamics.