A more detailed look at the waterways of the Flaness have been on my to do list for a very long time. When I did the terrain overhaul last year I had a river map in the sights, so I took the time and re-traced all the waterways and placed them on a separate layer in my terrain file.
The goal is to create a map that at a glance can give you the size of vessel you need in order to navigate all the major and mid sized water ways across the subcontinent. My sources for this are the river section in the 1983 Setting Booklet, From the Ashes setting booklet and the Living Greyhawk Gazetteer from 2000, for rivers that lack information I have used my own judgment to fill in the blanks.
The preview is 6000 pixels, and categorize rivers into 4 size categories. Ocean equivalent rivers (Dark Blue and wide) - wide enough to accomodate even ocean going vessels.
Smaller Sail ships - (Slight lighter blue and bit less wide)
Barges and other large river adapted vessels - (lighter blue still and narrower)
Small vessels with oars and paddles - Lightest blue and thinnest)
You can download the River Map preview here: https://www.dropbox.com/s/rs1wrmp5y9vfibz/Rivers%20w%20Label%206000px.jpg?dl=0
Work on the River Map continues and the final version can be integrated with the full Flanaess Map on top of the terrain.
Another alternative is to view all the map labels on top if the river layer.
A big thank you to all my Patreon members who make it possible for me to for on this as a professional project!