Unnamed Regional Map (River Police check)

[Raptori]

In essence, water - streams, rivers, etc - flows downhill from mountains to the sea, and as they flow downhill they join up with each other - forming bigger streams, then rivers, then larger rivers. I think a useful analogy is that a river is roughly shaped like a tree, with the base being river mouth at the coast and the thinnest twigs being streams on the slopes of a mountain range. Obviously with rivers it's a bit more complex, since they can and do form lakes and do all sorts of other cool stuff in unusual situations, and since there are things which govern where they will appear (which was part of what Pixie was talking about) but the vast majority would follow that simple principle.

So yeah, in summary, the rivers in your current map look fine