Friday, August 1, 2014

The Lake of Unknown Depths

A few weeks ago in our weekly Greyhawk chats there was a bit of discussion about the Azure Sea and the Flanaess' largest freshwater lake, Nyr Dyv "The Lake of Unknown Depths." This is some follow up research for those interested in esoteric Greyhawk information. As you should already know, Nyr Dyv is centrally located on the map, so obviously much of the game setting revolves around this important lake. Nyr Dyv is a busy waterway connecting many rivers and nations, and it is also known for monsters that lurk in the deeps waiting to prey on ships. But how deep is the Lake of Unknown Depths?

Gygax wisely provided us with some data in the Darlene hex maps. The oceans and seas are provided with seven color bands (light blue to purple) showing distances in from 0-30,000+ feet. The Azure Sea for comparison covers all seven gradations of depth, each color band in this region is about 1-2 hexes (30-60 miles) across. This means to get to the deepest part of the Azure Sea, one must sail nearly 720 miles off shore. Further comparison shows the Dramidj Ocean to the northwest similarly covers a seven band depth over 720 miles from the mainland.

Now putting this measuring system to Nyr Dyv we see it covers only five color bands; from light blue (0-600') and ending at purple (30,000+ feet) and only a staggering 40-50 miles from shore. This means the Lake of Unknown Depths drops off fast. A barge leaving the Selintan River into the Midbay on Nyr Dyv is comfortably sailing in up to 600' deep waters a mere 10 miles out. Heading out toward Admundfort Isle, the barge would soon enter waters 600-12,000' deep only 20 miles from shore (skipping a color band entirely). This is already dangerous waters where sea creatures might hide. Sunlight underwater is gone at about 330 feet deep so you won't find too many sentient races this far out unless they have darkvision.

As the barge then begins to sail into waters 30 miles out, the Nyr Dyv nosedives to 18,000 to 24,000' deep. How dizzying far did the lake fall off? The majority of Earth's abyssal plain is on average 13,000 to 18,000' deep that's how far. Out in these waters I'd expect to only be harassed by truly massive creatures like dragon turtles or giant sea snakes, if that. The rest of the journey from 30-60 more miles out to the middle of Nyr Dyv descends two more color bands 24,000-30,000' and beyond. The Mariana's Trench on Earth is 36,000' deep at it's lowest point and it's about 1400 miles from the mainland!

So Nyr Dyv lives up to it's mythical unknown depths, but comparing it to an oceanic trench is unfair. Earth's oldest and deepest fresh water lake is Lake Baikal in Siberia. Amazingly, Baikal is a mere 5387' at it's deepest. That is only two color bands by Greyhawk standards so Nyr Dyv is six Baikals deep! The Lake of Unknown Depths is a fantasy world body of water however, so how does it compare to the Flanaess' two other major lakes? Lake Quag is 600-6000' (3300' average) and Whysestil Lake is 6000-12,000' (9000' average). This makes both lakes quite impressive by real world standards without the presence of Nyr Dyv which is truly in it's own category.

A couple more questions to ponder. One, how do sages explain such an impossibly deep lake? Well scientific minds will most likely say plate tectonics, but so much of Oerth's geography has magical implications I don't see how Nyr Dyv can be entirely natural. Consider that the highly magical Isles of Woe in prehistory sunk beneath the Nyr Dyv, so that's no small disaster there. Lastly, is Nyr Dyv the largest body of fresh water on Oerth? Maybe. Despite more recent canonical maps of the globe, the Guide to the World of Greyhawk teases that "legends and tales report a veritable (fresh water) sea far to the west, if such stories can be believed." Could this lake have been wiped out by the Rain of Colorless Fire and existed within the Suloise Empire? That's for a topic for another day.


Dwight Grosso said...

Magic for sure! Maybe there is a portal to the elemental plain of water down there. That would make a nice explanation! Incredibly large thermal vents, or passage way to an even larger under gound sea might be plausible.

Raymond said...

Outdoor Geomorphs says:
If the owner of the fifth booth on the east side (counting from the north) is engaged in
conversation, he will relate a tale about his adventure on the Lake of Unknown Depths, where a very friendly
mermaid told him of the City in the Lake. If bribed with no less than 10 gold pieces in goods or cash he will
draw out a map showing where he thinks the fabled city lies beneath the waters (he is right), and he will warn
whomever it is he is telling about it that there is a dreaded monster guarding the crystal steps down to the city.
He can tell nothing more. (See #56, Society of Sages, for details of which sage knows what about the legend of
the City in the Lake.)

What is "#56, Society of Sages"?


Icarus said...

@Raymond … this is quite some time later, but, I thought I would answer your question:
"Outdoor Geomorphs: Walled City" is referring to how to use the generic city maps, and to prepare a key for them. It gives examples of places that a DM might make up for use in his campaign. It says, " those places which are important must also be numbered and keyed. For example: … " It then gives three examples of keyed locations, starting at #s 1, 2, and 3.

It doesn't get as far as #6 Old Town Barracks, #11 Riverman's Hostel, #39 which is numbered but not given a name, and #56 the location of the Society of Sages, all of which are mentioned in the descriptions of locations #1, 2, and 3.
If one were using the CoG Boxed Set, #11 could correspond to R11 Barge Inn.