[Tagging] Flood mark or high water mark

[Robert Szczepanek]

W dniu 05.08.2018 o 12:23, Volker Schmidt pisze:
> Flood marks and high water marks are not necessarily the same thing.
> Read
> https://en.wikipedia.org/wiki/High_water_mark
> to get the gist.
> There are ordinary high water marks (and I suppose also the opposite, 
> ordinary low water marks) which are based on the regular tides in the area.
> A flood mark would be a marker for the water level reached in certain, 
> particular events.
> I am not sure about terminology in different jurisdictions, but the 
> concept seems to be clear to me that there are two different things we 
> want to tag.

I would like it to be so:
- flood marks as flood signs,
- highwater marks as tide signs.
But even in recent scientific papers this division is not so clear.

Another issue is that from the beginning, on OSM wiki
https://wiki.openstreetmap.org/wiki/Key:historic
mark related to floods is described as
historic=highwater_mark

What would be the optimal tagging solution from OSM point of view?

regards
Robert