Thanks for your comments, but are you sure about this ? The canal areas I have tagged were precisely the only one not having water:canal on the enclosing area. The linear features have the tag waterway:canal (and not water:canal). But you are much more experienced than me. I let you decide

thanks for your explanations. Sorry, it was not vandalism. It is my first edits... I'll read your document osm-addresses.pdf. Looks very interesting.