[Tagging] siphon underpass

[Wolfgang Zenker]

Hi,

* Volker Schmidt <voschix at gmail.com> [170608 15:40]:
> I am looking into how to tag a frequent feature in my area, i.e. a siphon
> underpass, known in Italian as "botte a sifone" or "botte sifone" and in
> French as "pont siphon". This is a non.connecting waterway crossing where
> the lower waterway passes through a U-shaped siphon. The bottom part of the
> U is a tunnel that is lower as the normal level of the waterway.
> [..]
> I could not find any tagging schemes for this in OSM, but I may have missed
> them in ignorance of the proper technical terms.

in German this is called a "Düker". Unfortunately there does not seem to
be a special term for this in English; all translations that I could
find used "culvert". I would tag it as tunnel=culvert and suggest to use
a subtag to specify that it is a special type of culvert, like
culvert=syphon or similar.

Wolfgang