I think I understand what you are trying to say. I made a very long story for the region first, and tried to put everything that is in the story into an image. This is the result. The whole campaign setting can be
found here (in french).
To make a
very quick english summary, this region has been slowly flooded twice.
It is a very large magical swamp. The Maelstrom at the center is the desperate solution of an alliance of powerful mages to "suck up" the water of the land by constantly magically draining the water in the center (which is then directed back into the Gulf of Dewborn, named after the archdruid they made a pact with to create that delicate balance).
However you are quite right, I don't really know how rivers should behave, I will try to rearrange them by looking at some other maps found here perhaps... My goal is to make the Maelstrom (in the middle of the map) the centerpiece of which everything "water" (rivers mostly) begins or ends. Also, I need a lot of "chaotic rivers" since there is a confederacy of river pirates (who also helped in the creation of the maelstrom, in their own way).