[Tagging] Waterway direction

[M∡rtin Koppenhoefer]

2010/9/1 Anthony <osm at inbox.org>:
> honestly, I can't figure out what that is or how it applies.


I don't know how you call this in English (but probably it is called
culvert), this is a closed tube for water which goes down on one side
of the obstacle (e.g. road), the horizontally under it and up on the
other side. As it is working without pumps it is required to be filled
up with water at any time. Basically it work like a siphon. We call
this "Düker" in German or "Duiker" in Dutch.

http://dict.leo.org/?lp=ende&search=d%C3%BCker

OK, got it (but the article is not mainly fitting):
http://en.wikipedia.org/wiki/Inverted_siphon

cheers,
Martin