I have a wonderful underground base with cool carpet designs! Except one big area that is marsh! Ruins the whole look... with Alpha 9 is there anyway to get rid of the marsh??
Only with mods. pretty sure they all break saves, though.
This is the one I use for that:
[MOD] (Alpha 9) GARDENing (https://ludeon.com/forums/index.php?topic=10643.0)
I had the same problem so I bordered it with stone and decided it made a lovely indoor water feature. Very modern and environmentally sound.
But no, at the moment there's no way to remove it.
You could always activate dev mode. Place stone there (pick - place direct thing -> marble/slate/limestone etc.) then you can go and select destroy and click on each individual spot you placed the stone. It should, if I remember correctly, place a flooring of the same time of stone where the water was.
Handy little trick I figured out on my own.
The above works but you need to click on a square twice with the rock you're placing. The first click places the piece of rock, the second also alters the floor under it.
I haven't tried it out, but the Misc/MAI mod adds a drain pump which is suppose to remove water and I think mud.