Great Divide Basin, Wyoming

[Layne Bracy]

This area has always made me curious. My atlas shows an area in Wyoming where the Continental Divide splits and then rejoins, forming a loop. It is labeled Great Divide Basin.

Question 1: John - how did you deal with this? Did you list the peaks on both halves of the circle?

Question 2: Can someone justify drawing the CD lines this way? My thought is that if you started filling the basin with water, it would eventually start overflowing on one side or the other, and you would know which half of the loop is the true divide. Or, is it that one of the 2 junction points are lower than anywhere else along the loop? In that case, whenever the water level reached the lower junction point, it would start spilling out into both drainages at the same time.

[John Kirk]

I dealt with it by leaving out the eastern rim. I'm open to debate about it, but a non-draining feature (albeit very large) really goes against the idea of what the divide is supposed to mean in my opinion.

[Layne Bracy]

Yes, I agree it's somewhat unsettling.

I got a PM on 14erW from someone saying that the "where the water goes if filled to overflowing" idea is not the concept that is used to determine the divides. Rather, they said it is based on the watersheds, and if it doesn't drain to the ocean, then it shouldn't be included. (That came up in reference to the Great Basin of Utah/Nevada/etc.

My query now becomes: Where does the water in these self-draining depressions ultimately go? Does it not drain below surface to the ocean? Are there vast sub-surface lakes? Does it hit the mantle and turn to steam? I would guess it mostly goes to the ocean somehow, but I don't really know.

Maybe I'll ask my "source".

[cftbq]

I've always been fascinated by the GDB, too; I'd like to explore it someday. (Anybody know about ownership/access issues??)
My $.02: Your source is right; the concept of a Divide is based on where water drains on the surface, without reference to the meanderings of underground water. That underground water should, eventually, reach an ocean somewhere, but which one would depend on the location and shape of impenetrable underground rock formations, and I'm not sure anyone knows enough about this to give a definitive answer.
If enough rain ever fell to fill the Basin, it seems inescapable that a low point on the rim would become the outflow point, and it would be very unlikely to be one of the junction points. Therefore, the water would, indeed, drain into one ocean or the other. But that much rain doesn't seem likely to fall there any time soon...