04-23-2014, 03:55 PM
Yes there are a few. See https://en.wikipedia.org/wiki/Bifurcation_%28river%29 and also Isa Lake - Wikipedia, the free encyclopedia. But note that in all of the cases they are on geologically unstable places. Specifically for the Teton Two Ocean Pass its on the North America Continental Divide and the Isa is at Yellowstone. These places will only exist temporarily and in a few hundred years or perhaps a little more but trifling geologically, one side will dominate the flow. There are more that normally only flow in one route but during floods will cause the flow to exceed the capacity of one side and will then have two paths to different places. It is a certainty that at the very edge of the catchment basin where it meets its neighboring catchment basin then a drop of water is critically unstable in its route to the sea. There would exist many places where the flow is a merest trickle and then bifurcates but the more considerable the flow of water the harder it would become to show the bifurcation. A larger flow would erode one side faster than a trickle over the flat ground on the edge of catchments.
04-24-2014, 11:41 AM
I understand all that.
But in my mind, something that I had (for awhile) considered 'impossible' is merely implausible... and that's a big difference. Especially when creating fantasy maps.
04-24-2014, 04:03 PM
In fantasy, physics need not apply. A DM I once knew decided that the big mountain in the center of the island should disappear, leaving a big hole. The large river that had flowed from the mountain to the sea now served as a channel for the sea to flow back into the big hole. Implausible, but possible. And certainly not stable. Ever since the big hole appeared just south of the Sea of Fallen Stars in the Forgotten Realms, I've been waiting for some enterprising gnomes to dig a canal from the sea to the hole and set up a few waterwheels on it. The unintended erosional consequences and migrations due to flooding would be hilarious!
04-24-2014, 05:25 PM
04-24-2014, 10:04 PM
Or the one from the Gulf of Aqaba to the Dead Sea, or the one from the Gulf of California to the Salton depression, or the one from the Red Sea into the Afar depression. It's a popular topic. It's also a major ecological disaster for the ever so fragile ecosystems (except for the Salton depression, which has already had that particular disaster). But the Forgotten Realms one is particularly interesting because the hole is very deep and the distance not too far. When the gnomes put their giant hamster wheel-powered excavators to work on a basic canal, accidental erosion could VERY quickly turn it into a miles-wide waterfall unless there is a very solid ridge in the way. It's mostly plains with no particular hills in the way...
06-15-2014, 01:17 PM
I didn't know that about Lake Baikal. Thanks for pointing that out. I should have caught myself with the obviously inconsistent statement about the Great Lakes. I've been looking at fractals lately and river systems are sort of like that, especially as you look at them in closer and closer detail.
Originally Posted by Hai-Etlik
Last edited by Trismegistus; 06-15-2014 at 01:19 PM.
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