Caves below sea level?

[Doug McCrae]

In Eberron, I'm wondering if Sharn's Cogs, which seem to be below sea level, are actually possible.

Can you have caves below and relatively close to the sea that aren't flooded?

 

[gizmo33]

Can you have caves below and relatively close to the sea that aren't flooded?

Why not? Just have some landform that prevents the sea at high tide from swamping the caves. AFAIK Dry land exists below sea-level when there's intervening land to keep out the water. It probably also depends on where the water-table is. I think these are all solvable problems though and I would just be comfortable in handwaving it rather than expecting to have to submit my design to a geologist for approval.

Random thought: I believe that the Sumerians/Babylonians envisioned the earth resting on an abyss of water - so that if you went deep enough, you'd hit water. That would mean that below-sea-level caves would also have to be shielded from that water as well.

(Edit: I'd look for caves in the area of the Dead Sea that might qualify - there are hills in the surrounding area, and I guess it's possible those hills are still lower than sea-level.)

 

[Brown Jenkin]

In Eberron, I'm wondering if Sharn's Cogs, which seem to be below sea level, are actually possible.

Can you have caves below and relatively close to the sea that aren't flooded?

Like the Chunnel? Sure you can have caves bellow sea level. The only problem is if they are breached then they will flood. There would still be air pockets though even with flooding unless the air has an escape route.

 

[Prince of Happiness]

Sure, yeah, why not, f*** it.

 

[Raven Crowking]

In Eberron, I'm wondering if Sharn's Cogs, which seem to be below sea level, are actually possible.

Can you have caves below and relatively close to the sea that aren't flooded?

Only if the caves were at some point above sea level, and there is no way for the air to escape when the sea level rises, resulting in a trapped pocket of air. (You can experiment with a glass in a bathtub to demonstrate this, as well as to determine the angle at the cave entrance needs to have in order to prevent air from escaping and/or the rough % or air pocket versus water-filled cave.)

EDIT: Sorry, not an Eberron guy. I was envisioning caves accessible from the sea that weren't completely flooded.

 

[tomBitonti]

Realistically, or in game?

Realistically, I image that deep holes have serious problems with flooding. Temperature and pressure increases create serious problems as well.

In game? The underdark is envisioned to be *miles* deep. Far deeper than could ever be possible without resorting to magical shenanigans. The game system completely ignores practical issues in regards to deep holes.

 

[Wik]

You can go beneath the sea level, above ground or not, only if you are in a relatively dry area. Otherwise, all that area will fill with water (due to precipitation). At least, that's how I always thought it worked.

Most areas that dip below sea level, to my knowledge, are in arid zones.

 

[Raven Crowking]

Realistically, I image that deep holes have serious problems with flooding. Temperature and pressure increases create serious problems as well.

That's true. I've seen a mine that you couldn't get into without a canoe, and this was in Wisconsin. However, if you could pump the water out, or if you were taking about a pocket in relatively solid (nonporous) rock, you'd be okay. As a good general rule, if the air can get out, the water can get in.

In game? The underdark is envisioned to be *miles* deep. Far deeper than could ever be possible without resorting to magical shenanigans. The game system completely ignores practical issues in regards to deep holes.

Also true.


RC

 

[johnnype]

I'd say yes if for no other reason than the fact that it's a fictional world with magic. Anything is possible.

On a related note you might want to check out the Planet Earth episode that deals with Caves. Amazing visuals. There is also a very interesting segment where they show a partially submerged cavern where (I think) salt and fresh water meet. Truly amazing it looks like a pool of oil and water. Absolutely beautiful.

 

[Jack of Shadows]

Well,

I'm not entirely sure the Cogs are below sea level Remember that Sharn's foundations sit upon a high cliff overlooking the Hilt. So high that a section of the city is built right onto the sides of them. Also with the Magma vents beneath the Cogs any water that got in would turn to steam. And then there's the effects of the coterminous Air zone. So essentially real world physics need not apply.

Jack.