I'm building a big ol' island with Axiom and WorldPainter, with a lake in the middle with a couple of short rivers flowing off into two smaller lakes. The path of this river is marked with Stripped Oak Wood. Is there a good way of using the mod Axiom to fill it, or is it best filled by hand? And how would I go about that?

Also, texturing and detailing comes later. That's why everything is just stone for now. This is part of a MUCH bigger map I'm building, so all advice will be a colossal help. Thank you :)