Some of the rivers are more like "streams", as you see the image represents a pretty small area. If you check the linked blog, you see why it ended up like this. I don't plan to use this map directly. Since most rivers / streams flow from the hills / mountains in the norht towards he lake in the south, and with this, if a stream has to "avoid" any rock, etc. it should tend to turn to south, and not towards north, and this is why the merge works this way.

The yellow thingies are: Sandbars.