How do I kill these goblins?

I've got a little bit of a predicament. I created a pit to dump goblins in, then I tried to fill that pit up with water in order to kill them.

Of course that's when I find out that you need to actually have the place filled with 7/7 water and a floor above them in order to kill them.

Unfortunately, I left a few holes open in the level above to drop them in, and I can't do anything about it because the moment I queue up a floor hatch to fill the holes, the dwarves suspend the construction out of fear.

How do I fix this?

Level 1

Level 2

(The goblins are dropped in from pits above. Those floor hatches are suspended.

Solution 1:

Right.

Firstly you need to kill the goblins. You can't finish anything until that is done - As others have suggested marksdwarfs are the way to get this done. Even an untrained marksdwarf may hit something sometimes so make a squad and just tell them to station on the floor above. They will fire through the holes and eventually kill all the goblins.

Once they are dead, you can build your hatch and be happy in the fact the goblins are now doomed.

Personally, i'd make a ramp and have the hatch a floor higher, so they drop 2z levels into the water - the first drop will stun them, and you'll be able to fill it to 7/7 and make sure they drown without them climbing back out :)

Solution 2:

Some general ideas:

1. Fill the pit with magma.
2. Put other things in the pit that will kill the goblins: Just flood them in a tide of war dogs, cats, bears, etc.
3. Make a giant room under the water and create a cave in. (Never tried this myself)
4. Freeze all the water in the pit and kill them the old fashioned way.

Solution 3:

You could try sealing off the room above the drowning pit from the rest of your fortress and raising the water level until that room is also filled up to 7/7. Then it won't matter which level the gobbos are on, they'll drown anyway. Just make sure to seal to upper room completely before filling it, in order to avoid unwanted water and goblin leaks.

Once the current batch of goblins are all dead, drain the pit and redesign it to avoid this problem in the future.