Handling river bifurcations

[Janjko]

There is one river in Kosovo, Nerodimka river, that bifurcates (forks downstream), but it is unique in that it forks into two separate basins, Black Sea, and the Aegean sea. This isn't handled in this project.

This is probably not very easy to solve, so I have no problem with not solving it in this project. I just wanted to raise the issue here, so it is known that it exists. Here is the river relation.