A good start, it does look however as if mr. Erikson neven had a visit from the river police, but then again the map in the books is so compressed its hard to really see where the rivers go. Just remember that rivers don't split - they only come together and by the easiest route finds the ocean
I don't know if this picture is in full size, but if it is, I would probably go a bit up in size to get in more details - but then again- thats me, love details