World Building - Very Shallow Sea?

[The Colonel]

As a sanity check for a worldbuilding feature, is there anything intrinsically silly or credibility straining about a significant body of seawater that is only perhaps five or six feet deep on average?

[AlexanderHowl]

It will evaporate pretty quickly without massive inflows. It would also be a very dry world, as it would have less than a one-thousandth of the water as the Earth (it would be drier than the Moon by comparison).

[Flyndaran]

A very old geologically inactive world may eventually become one with a near global shallow sea. Erosion evens out terrains.
Though six feet is really shallow and a narrow range to maintain over square miles let alone a large sea scale.

[gruundehn]

How big a percentage of the oceans is this one sea? A sea connected to two other seas but is on a shallow shelf might work.

[ericthered]

Small area is fairly believable. The great salt lake has an average depth of 14 feet. That's not an ocean though, that's a inland lake. Lake Natron is another one, and that's even shallower. I wouldn't characterize either as containing "Seawater": both have their own mix of chemicals in ratios far above the ocean.



For actual oceans, the java sea is "shallow", but still has an average of 50 meters.


Its not inherently silly, but you'd need some strong geological meddling to pull it off.

[The Colonel]

Originally Posted by gruundehn

How big a percentage of the oceans is this one sea? A sea connected to two other seas but is on a shallow shelf might work.

I was thinking either a large bay - perhaps Aegean sized or so - or possibly a Pacific style archipelago. Maybe a bit of continental shelf covered in Cays...

I'd be tempted by thick layers of coral as well...

[Rupert]

Originally Posted by AlexanderHowl

It will evaporate pretty quickly without massive inflows. It would also be a very dry world, as it would have less than a one-thousandth of the water as the Earth (it would be drier than the Moon by comparison).

The rate of evaporation shouldn't be any different from a deeper body of water with the same surface area, assuming the same surface temperature, etc.

[PTTG]

Tides complicate this.

If it's connected to other, larger bodies of water, it could easily have a tidal range of 6-12 feet or more, resulting in the whole sea at least nominally washing away in the tide, and then doubling in depth over its average.

If it's not connected to the world-ocean, and it's not very very large, it should be OK, but it'll be a salty inland sea. Throw in frequent rains and make it a part of a functioning watershed (have some kind of outflow) and you'll be OK.

Or get rid of the moon and tides, of course.

[acrosome]

A large area around the Florida Keys has depths less than 15 feet, and a lot of it in single digits. A large river delta might work, too, or mudflats. I'd kind of doubt "Aegeaniszed" examples of those, though.

A very old world with little tectonic activity, heavily eroded into an almost-uniform elevation is probably your best bet. Or, a very high gravity world, since that results in a more shallow angle of repose and more erosion, too, maybe?

[evileeyore]

Originally Posted by The Colonel

As a sanity check for a worldbuilding feature, is there anything intrinsically silly or credibility straining about a significant body of seawater that is only perhaps five or six feet deep on average?

Do you have elves in the world? Magic? Other such fantastical things?

Then don't worry about it.