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Author Topic: Unblocking Floodgates?  (Read 1377 times)

Bomrek_BucketMonger

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Unblocking Floodgates?
« on: September 01, 2020, 01:54:31 am »

Hi Guys,
I'm building a drowning chamber but some debris got stuck in the floodgates. Is there a way to get it out or am I screwed?
https://imgur.com/a/OWuDmxJ

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Leonidas

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Re: Unblocking Floodgates?
« Reply #1 on: September 01, 2020, 03:12:48 am »

You can get it out.

You can dig a drain next to the stuck item, then flush out the item.

Or better yet, you could put a drain at the narrow point to the north where you tapped into the natural water, drain the entire system, and re-work the design to avoid this problem in the future.

To drain large volumes of water, dig vertical U/D staircases below the drain point. That's z97 in your case. Let the water drop four or five levels, then dig a large conduit that gets rid of the water. However you design the drain, make it big enough to easily handle the water that you're draining.

How do you get rid of the water? On a small embark, the map-edge drain works well. Just carve fortifications into the tiles on the edge of the map, and water will flow off the map. If that's not convenient, then maybe you could dump the water into a cavern and let it find its way off the map down there. You could also dump the water into the magma sea, though that will lower your FPS.

On the layer below the water, z97 in your case, build a way for your miners to walk out safely once the water comes crashing down. Include multiple doors on that corridor to make sure that the water doesn't follow the miners and flood your fort. Build retractable bridges on the U/D stairs on z97. Those bridges will open and close the drain.

When it's all ready, have your miners dig down stairs on z98 from below. The water will come crashing down, showering the miner but not drowning him or washing him away. If your drain is big enough, then all the water will flow off screen without backing up.

Draining the whole system will take a while. But once it's empty you can replace those floodgates with bridges, which can handle debris. You can also fix the original design problem, which was that you didn't build a blocking bridge at the water source when you tapped it. Always block fluid at the source, and then again further along in the system.

Here's an example from my current fort, where I drained a cavern at the map edge. The water is on z51. Those down stairs were the last piece of the system.
Spoiler (click to show/hide)
Here is z52, with a miner escape tunnel and retractable bridges blocking the U/D stairs. The drain is currently closed.
Spoiler (click to show/hide)
z49, 48, and 47 gave the water plenty of drop to avoid backflow. Since this was on the edge of the map, I edge-drained them all, though it probably wasn't necessary:
Spoiler (click to show/hide)
On z46 I started a double-height room to give plenty of space for the water to spread out before draining off the edge of the screen. This probably wasn't necessary, but I like to overdesign when fluids are involved.
Spoiler (click to show/hide)
And z45 was where the water finally hit bottom and started draining. This was a few years ago, so trees have grown up in the meantime.
Spoiler (click to show/hide)
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Bomrek_BucketMonger

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Re: Unblocking Floodgates?
« Reply #2 on: September 03, 2020, 10:39:12 pm »

Thanks man. I really appreciate the advice. I'll go fix it now. I'm never using floodgates again.
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Thisfox

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Re: Unblocking Floodgates?
« Reply #3 on: September 08, 2020, 07:31:08 pm »

Please note: if you drain into the cavern, I recommend not using it for anything else. It might well drain away, but underground lakes seem to have their own "special" equilibrium, and it's remarkable how that can become problematic if large amounts of water drain into them. Be ready for cavern flooding, waves, or, in one case, with the aquifer draining in there for a while, then shut off, I had the entire thing drain away and lost my underground lake entirely. It doesn't necessarily act like you expect.
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muldrake

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Re: Unblocking Floodgates?
« Reply #4 on: September 17, 2020, 09:14:35 pm »

Thanks man. I really appreciate the advice. I'll go fix it now. I'm never using floodgates again.

Why do floodgates even exist?  They're useless for their only purpose, or at least inferior to bridges.
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Leonidas

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Re: Unblocking Floodgates?
« Reply #5 on: September 17, 2020, 11:40:58 pm »

The only use I can imagine for floodgates would be if you're building a precise mechanical setup. Floodgates have an activation delay, so they could perfectly synchronize with bridges.
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