Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Immortal-D]

If no aquifer was present, I would dig a large section of the level under the ocean, replace the floor with grates, then dig upramp on 1 tile.  Hopefully the room for water to spread combined with immediate drainage would save him.  That is not an option (that I can see) this time.  I have to pierce the ocean from the side, which will kill the Miner just as sure as if he were digging into a magma pipe.  The land tiles adjacent to the ocean are all Light Aquifer.  The embark has 4 ocean tiles, so pumping is not an option.  Any suggestions are appreciated.

As an aside while I'm thinking about this project; If I successfully drain the ocean, I can access the ocean floor.  If I channel the ocean floor and expose the heavy aquifer, can I then in the future drain the ocean into it?  Or would the ocean simply 'fall' into the exposed aquifer and replenish?  Or not replenish I suppose, which is actually worse.

[PatrikLundell]

I had some trouble following what you wrote, so the below may be off.

There is a safe method for digging into a magma pipe from the side, exploiting upward ramps and a bridge. I've never used it myself (haven't had a need to), but I think it's described somewhere on the wiki.

Otherwise I'd use a cave-in, i.e. dump a cart load of magma into the ocean above a tile that just has a roof between the ocean floor and a tunnel below. Note that you'd want a pit with a depth of at least one tile under the target tile for the newly formed obsidian tile to fall into, or it will just plug the hole it just made in the roof with itself (and you don't want another roof as the floor of your tunnel, or the cave-in will smash through that one too).

Draining the ocean requires that you build walls along the embark ocean edges to stop water from flowing in through them. That can either be done using obsidian or by using pumps and constructed walls.

If you expose the ocean to the heavy aquifer the water should drain into the aquifer and disappear, but, as mentioned above, you you don't plug the influx of new water all you'll achieve is an FPS drain, but not an ocean one.

[anewaname]

I did something like this without miner casualties. Dumped the ocean into an aquifer so buildings could be built on the ocean floor. No miners died, but the FPS was lousy for a long long time while the ocean drained into two corners of the embark. It was a 5x5 embark, maybe 70% ocean tiles and it had three 20x20 towers built in the center of the ocean floor. The important thing about the embark was it had a multiple-z ocean and corners in the deeper ocean to allow a diagonal channel (to depressurize the water flow, which is why the miner survives this).

If this was the northwest corner of the embark map where the little bit of deeper ocean was...
7777nn   7=ocean, n="natural wall"
7777nn     A="a tile directly over the aquifer", B="the tile where the dwarf eventually stands to channel tile A"
nnnnAn
nnnnnB
The pre-work involves working directly below tile A. Tile A represents the spot where the water will fall straight down into the aquifer and there needs to be a functioning floodgate between tile A and the aquifer below it.

Once the pre-work is done, open the floodgate and channel tile A. The miner doesn't get wet, but it will take a couple of years for the central area of the ocean floor to drop to 1z depth to allow building on the ocean floor. Once your ocean-floor constructions are 1z above water level, close the floodgates to restore FPS.

[DwarfStar]

I think I’d just build some floors held up by a lever-connected support. Arrange for them to crash through the ceiling of a large room dug directly out under the bottom of the ocean, with ample drainage (drop down another a level or three on the way) to a map edge drain. If you establish the drain first, the aquifer shouldn’t be a problem.

It does probably depend on your exact embark geometry how big this excavation needs to be, for enough water to be removed to allow construction. You could even put multiple drains ringing the building site if needed. You could put a raising bridge or a bunch of floodgates as a plug if you eventually want to refill the ocean.

Btw you can encourage the water to drain out faster (or generally control the water to keep it away from  your building site) by digging channels in the ocean bed to direct the water towards your drain.

[Immortal-D]

I appreciate the info.  The problem with using the magma bridge/upramp solution is that unlike magma, water pressure is not affected by vertical movement.  That said, a sufficiently long diagonal tunnel might be enough to stem the flow.  You can't normally build at map-edge though, right?  Ideally the initial drain will work faster than the ocean refills, but if not then I'll have to consider obsidian casting as was mentioned.  Ultimately I'm not opposed to sacrificing a peasant (there's always a problem Dorf), it's simply the principle of the thing (this time).

[PatrikLundell]

You can build at the map edge if you're underground (I think it depends on whether it has been exposed to the sky or not). I typically wall off the caverns at the edges with no issues, but yes, you're probably restricted to obsidian casting for the ocean edge (or construction 10 tiles from the edge).