I made a stone post near the river(about 4 tile away from it) and going away from the water i went to set the wall. the land was clear but a small hump in the land.It wont let me clear this small hump even through i can work around it.So I am in trouble.I really think the water zone is to far out.I see no reason why you cant lvl your land next to the river.
It really strange that there no angle walls to help.For some river do ran at a angle.This also cut some of my land off from my walling it.