Thanks for working on waterways! One thing to keep an eye out for is to make sure the side streams are all flowing downstream. 

This one was pointed the wrong way but I've updated it. https://www.openstreetmap.org/way/1355059795/history#map=19/38.423370/-91.043371

There's a really neat QA layer you may find helpful/interesting. https://waterwaymap.org/loops/

Anyhow... keep it up! 