[Tagging] Modelling the relation between a waterstream and one of its resurgence

[Richard]

On Wed, Sep 09, 2015 at 08:55:44AM +0200, David Marchal wrote:
> Hello, there.
> I wondered: when a waterstream is known to be, instead of a real, separated waterstream, merely a resurgence of another one, how should the link between them be modelled? Which tags should I use, and in which relation? Should I tag the resurgence by itself?

map the underground stream if possible. I dont't think there is
a standard way to do it but location=underground might work. Some
people used variations of tunnel=* with additional tags for cave.

  http://wiki.openstreetmap.org/wiki/Cave
has some info and discussion on the talk page

If mapping the underground stream is not an option use the quite normal
relation waterway.

Richard