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

[Christoph Hormann]

On Wednesday 09 September 2015, David Marchal wrote:
>
> As I don't know where the intake from the first stream is, I think I
> can't map it this way. Besides, wouldn't that make the link
> exclusive, i.e. tell that the water only comes from one point and
> exits at another? If so, I can't either, as no-one can be sure of
> that in karstic systems: you can be sure that a ponor feeds a spring,
> but not that only this single ponor feeds only this particular
> spring, as there can be other ponors feeding this spring, and other
> springs fed by this ponor.

Which is why mapping this is not really within the scope of OSM - 
natural underground waterflows are inherently non-verifiable.  

You can and should map the surface phenomena related to the underground 
water flow of course - ponors, dolines, karst springs and other stuff.

-- 
Christoph Hormann
http://www.imagico.de/