I am considering adding an Athas Underdark to the adventure I am creating. Does anyone have maps or any other information about the Athas Underdark
Canon-wise? Not much. There’s under Guistenal in City by the Silt Sea, which has a large by Athasian standard underground area. You can assume that the City States are all built on prior, older settlements. There’s the hint that something large is underneath the Lake of Golden Dreams. Celik has a large ruined area that is being reclaimed… I’ve thought about putting a variant of the Pool of Radiance/Phlan-style dungeon there myself.
I have to believe that the source of all remaining water on Athas is actually below the surface, and once the civilizations above realize this they would adapt to living in the Underdark. I think that It may very well be that “extinct” races lost in the Cleansing Wars actually survived in the Underdark.
The Lost Cities of the Trembling Plains files on one of the FB DS groups has plenty of ruined goblin cities in the White Mountains near Kurn. IIRC there’s references to the Underdark in the Black Spine adventure - specifically the bit around Yathazor buried under the Black Spine Mountains.
Under Tyr is also a vast underground complex consisting of old parts of Tyr linked by multiple tunnels.
Folks above have covered most of what we know of the underdark of Athas. There was also a speculation thread on the Athasian underdark along with various ideas put together on this old thread. As for what became of Athas’ water there’s a lot of speculation about that here.
An old theory I had when I first started Dark Sun with my friends was that the water was somehow trapped under the Sea of Silt. There’s been mentions of habitable islands around the Sea of Silt where water spills free and creates small lakes and habitable isles in otherwise completely inhospitable lands. These days I suspect that isn’t where most of the water went, but I am positive there’s quite a bit under the silt.
Iirc, the Windriders of the Jagged Cliffs book mentions lifeshaped tunnels in the side of the Jagged Cliff that gives way to much deeper natural caves further inside.
This very bit about the water table is a key part of the story in my current South Tablelands game. I have a lot of the silt touched water brackish and saline if it isn’t filtered through enough earth. There’s a pocket under South Ledopolus that’s like this - the dwarves originally tried to dig under the sea in ages past to connect North and South Ledopolus instead of the current bridge.
The Ledo Islands benefit from ground water that isn’t tainted, but draws from the same water table. But you best be on good terms with the giants there if you’re thirsty.
In several places in Arabia and in the Sahara here on Earth there are brackish underground seas, and even in Libya, there were great engineering projects to extract from vast underground aquafers of pure water left over from prehistoric times, when the planet was more tropical, like Athas was in the Green Age. Since Defilers only extract resources around them, and most probably did this above ground, I have to believe that there is plenty of Underdark water, even if most of it might be brackish or tainted. If you know about sand dams they build in Ethiopia, you know that
One key aspect of my campaign will be water filtration and storage, be it solar stills, or desalination, cisterns, etc… whichever way the players can make the water palatable, without risk of disease or sickness. I study bushcraft and survival here in the real world so I want to apply some of those principles to this campaign.
They build sand dams in Ethiopia to trap water behind a dam, the dam eventually fills with silt and sand, but because there is plenty or space for water to be trapped in between the sand grains, water is also trapped and the sand layer stops all evaporation from happening. There are some good videos on Youtube about this, and more about the engineering projects they are doing to catch run off in Saudi Arabia and India, using rock walls.