-rivers always appear on tile bottom if moving horizontal
-rivers always appear on right if moving vertical
-The direction you drag your mouse is the direction of flow
For complex stuff, I usually break into sections. I do the outlet section first (still dragging downriver) and do each section in order from delta to headwaters. It's not perfect, but can be made to work.
There is usually some cleanup at the end to delete loose ends.
I have noted rivers in 25 have messed up flow characteristics.... it's not mandatory to make them perfect, just that they give "fresh water" bonus to the right squares.
-rivers always appear on right if moving vertical
-The direction you drag your mouse is the direction of flow
For complex stuff, I usually break into sections. I do the outlet section first (still dragging downriver) and do each section in order from delta to headwaters. It's not perfect, but can be made to work.
There is usually some cleanup at the end to delete loose ends.
I have noted rivers in 25 have messed up flow characteristics.... it's not mandatory to make them perfect, just that they give "fresh water" bonus to the right squares.