BUA ON waterway

Here is what the rules say.

Page 6, forth paragraph, last sentence:-
       “There must be a gap of at least 1 BW between area features,
         and between an area feature (other than a BUA) and any battlefield edge.”
Linear Terrain Features (i.e. Waterways, Rivers and Roads) do not need 1 BW gaps.
Also, at the bottom of page 6 it says “A road can end at a BUA on a waterway edge.”

Note however that having a Road touching a BUA that is touching a Waterway is
pretty pointless, and just a waste of one of the defender's terrain choices.

Yes, Deployment at the top of page 8 does say “The invader selects a base edge.
If a road crosses the battlefield, one of the intersected sides must be chosen,
otherwise any edge that is not opposite a waterway.
The defender’s base edge is that opposite the invader’s edge.”

But if a road stops at a BUA that is ‘on’ (i.e. touching) a Waterway, then players like
myself say it does not fully cross the battlefield, and is not intersecting a table edge.
And since the invader cannot choose a base-edge that is directly opposite a waterway
(thereby forcing the defender to deploy with their back to the water), then the road
has no effect and won’t limit the invader’s choice of base-edge.

Others may interpret things differently however.