Bay 12 Games Forum

Please login or register.

Login with username, password and session length
Advanced search  

Author Topic: Cavern to magma sea waterfall - engineering questions.  (Read 846 times)

taptap

  • Bay Watcher
    • View Profile
Cavern to magma sea waterfall - engineering questions.
« on: October 21, 2014, 09:49:08 am »

My most recent embark features an empty magma pipe without obsidian casing, so I have watched an amazing waterfall from the 1st cavern layer (of 2) directly into the magma sea. Result after 9 month in game (and about a 1000 caveins) is an obsidian shield on top of the magma sea. It is only partial as some area sitting above semi molten rock resists obsidianisation. So instead of obsidianisation and filling of the magma pipe until the 2nd cavern layer that I expected - I have a waterfall, mist, steam, magma mist and apricots falling directly from the surface 120 z-layers into the magma sea.

I intend to use the features of the embark and settle around the pipe, but first I have to stop this mess - I had fps down to 30 already w/ only 15 dwarves on 2x2 embark, w/o hell, pocket region and only 2 cavern layers :) - and I have some serious engineering questions in this regard.

What is the best way to stop the waterflow w/o completely destroying the 1st cavern layer?

I started walling off some parts standing on flimsy pathways / at times grates above the pipe, but this only increases the waterflow in other parts - I wanted to finish the section by a raising bridge, which does not work because I can't choose to raise it towards the water when constructing from the outside. I have some ideas for tedious workarounds, but would appreciate a better idea.

In the second step I plan to finish the obsidian shield above the magma sea. I imagine creating a floor out of magma safe stone, flooding it one layer deep with magma and then just lower the bridges in the 1st cavern layer to obsidianise the place. What happens with the floor or a bridge when you obsidianise the magma on it?

Engineering and architectural ideas are welcome.

Tacomagic

  • Bay Watcher
  • Proud Sir Wordy McWordiness at your service.
    • View Profile
Re: Cavern to magma sea waterfall - engineering questions.
« Reply #1 on: October 21, 2014, 11:02:15 am »

Absolute easiest way to stop a river is to temporarily drain it off the side of the map.

To do this, Dig a cavity as wide as the river underneath it to the edge of the map.  I'd start 6 to 10 tiles away from the map edge as you'll want some room to build.

Smooth and fortify the map-edge tiles to create a drain.  Next, build a raising bridge upstream of where you plan to puncture the river-bed to block the flow when raised.  This will allow you to turn off the drain if you want the river to flow again.  Link the bridge to a lever, and then construct a ramp tile downstream of the bridge.

Evacuate the chamber and get a miner to channel out the tile above the ramp (make sure you give him something else to do so he gets out of there).  This will cause most of the river to start to drain through the hole.  You should eventually be able to widen the hole enough to drain the entire width of the river into that drain.  You can then build a dam (either walls or a raising bridge).  Once the dam is built, pull the lever to close the bridge and block the flow off the map.

Boom, dammed river.
Logged

taptap

  • Bay Watcher
    • View Profile
Re: Cavern to magma sea waterfall - engineering questions.
« Reply #2 on: October 21, 2014, 12:13:06 pm »

Thank you... but but it isn't a river, it is a flooded cavern layer (wide open, easily 50+ border tiles producing water), that is why I was looking for a particularly non-invasive method to dam not where the water enters, but where it spills over into the (empty) magma pipe.

Tacomagic

  • Bay Watcher
  • Proud Sir Wordy McWordiness at your service.
    • View Profile
Re: Cavern to magma sea waterfall - engineering questions.
« Reply #3 on: October 21, 2014, 12:48:06 pm »

Thank you... but but it isn't a river, it is a flooded cavern layer (wide open, easily 50+ border tiles producing water), that is why I was looking for a particularly non-invasive method to dam not where the water enters, but where it spills over into the (empty) magma pipe.

Pretty much the same thing will work, just have to dig your drain all the way back to where you want to divert the water from

Alternatively, you could use a row of pumps to keep an area dry so you can do your work.  Just line them up to a full width across what you want to divert and have them pump onto a small, temporary aquaduct that hangs out over the caldera and dumps the water in there.  Anywhere downstream of where you set your pumps to draw from should remain mostly dry.  Since it's all flowing, you should be able to power the pumps from a water wheel or two placed upstream.
Logged

Loci

  • Bay Watcher
    • View Profile
Re: Cavern to magma sea waterfall - engineering questions.
« Reply #4 on: October 21, 2014, 02:31:14 pm »

Build some retracting bridges in the middle of the pipe, link them to levers, and retract them. Build additional retracting bridges to the edges of the pipe. The water will flow over the edge bridges and drain down the middle. When you have all the edges covered, pull the levers to seal off the pipe.
Logged

taptap

  • Bay Watcher
    • View Profile
Re: Cavern to magma sea waterfall - engineering questions.
« Reply #5 on: October 24, 2014, 05:23:52 am »

Thanks for all the advice. I tried doing the "messy workaround" style with pumps draining building areas which then are walled off. This worked fine for the easiest area, but on trying the second (with help from rain) I lost my expedition leader mason to an epic tumble 16 z floors down. Even later I had ogres - who could walk there because the steady drain into the pipe makes the area walkable - devastating my pumps. Trying to lure them into traps did fail when my militia commander failed to disengage from them and instead charged and finally she took the tumble too - but being unbreakable survived (even without any metal armour) w/ messed up arms, legs, shoulder and some minor stuff. Since then she made a splendid recovery - even defeating an infection. (In the end, I should not have bothered w/ the ogres, they all eventually fell down as well and did not survive.)

A nice additional problem for working w/ more pumps are the new-type mushrooms. They block access from above, but allow waterflow beneath and can not be removed from above. I can't even set up sufficient pumps properly for the more problematic areas.

So, I will resort to draining from below after all, but will reuse it to build some other waterworks (power generator, swim training) at the same time.