Building walls in water?

[faelyn]

Is there any way to build a wall in 7/7 water to stop its flow?

[Terminal]

You can build a wall in any tile occupied by a fluid as long as a Dwarf can stand on an ORTHOGONAL tile to do so, and as long as they are not swimming, which generally means that tile needs to be empty. Since fluids like to move from full tiles to empty tiles this is generally impossible.

There are three common methods of building down or up into water.

1. Wait for the water to Freeze if you are in a temperate or colder biome, then dig through the ice and build normally. If the water is underground, it will never freeze, so this method becomes impossible.

2. Use magma/water to turn the fluid area into obsidian, which can then be mined through. Controlled magma/water channeling can be used for dams and is fairly reliable, albeit it takes a fair amount of setup resources to work.

3. Brute force the fluid out of the way with Screw Pumps. They will pump fluid away faster than it can flow into a tile naturally. You can use screwpumps this way to create a 'dry' section of the fluid area that you can then build in. The most common example is to use them at a river to completely prevent water from flowing into a section of it. Having the screwpumps feed into channels that lead further down the river, and using secondary screwpumps to prevent it from flowing back into the river section you are building in.

Finally, there are a couple of uncommon methods involving Dwarven Black Magic™, but I have never actually had a reason to use them. One method involves using minecarts to shunt fluids through spacetime chasms and into the void and the other involves magma pistons, although the later is not all that good for moving large quantities of FLOWING water and keeping it from coming back.

[Einsty]

Underground you can use controlled caveins to drop tiles from above into the water. Be sure to evacuate the area though as there will be some fallout.

[faelyn]

Thanks for the help.

[captainamaziiing]

I waited for Winter, then went to the upstream end. Tunneled under it, then drained it right off the edge of the map. Added some floodgates on levers and waited for the ice to melt. Then I could shut off the river completely whenever i felt like it.

[McOrigin]

And then comes a building destroyer that can swim and dive and destroys those floodgates you cannot reach anymore :D

[Terminal]

Building Destroyers are currently bugged and cannot destroy buildings, including floodgates, but the principle should still be respected. Ideally, you should always use bridges in place of floodgates anywhere you expect a building destroyer might target if left idling. Titans and Forgotton Beasts, in particular, are both amphibious and will go into rivers/streams/moats/dams to destroy your buildings.

[Diarmuhnd]

Originally posted by faelyn:

Is there any way to build a wall in 7/7 water to stop its flow?

No. But you can drain the water faster than it fills with rail carts and dark arcane magic. That will let you run in some builders and get it built.

Holler if you need the link to the Twiste Logic Gaming youTube channel which has the recent video tutorials on that dwarven mechanical engineering magic.