[Tagging] Flood mark or high water mark

Graeme Fitzpatrick graemefitz1 at gmail.com
Wed Aug 8 01:33:40 UTC 2018

On 8 August 2018 at 05:00, Robert Szczepanek <robert at szczepanek.pl> wrote:
> Before making any changes in wiki I would like to find final agreement on
> that topic.
> "Flood level" (highest water table) is usually only one of several
> informations we can find on "flood mark". Others can be date of flood,
> inscription, etc.
> Physical object mapped in OSM is rather mark, not just water/flood level.
> So "historic=flood_mark" is probably more generic.

Yes, flood_mark would be a better wording than flood_level

>> Yes.
>> Complication .. a historic king tide combined with a storm event may be
>> considered a historic flood level.
>> But 'normal' high tides should be part of the water way tagging system.
> This can be sometimes hard to distinguish. But tide+storm I would consider
> rather as flood event - probably higher level comparing to periodic tides.

Quite definitely - a storm surge becomes a flood, not just a very high tide

> In such a case we can find in on place two types of marks:
> * historic=highwater_mark - with information about periodic highest water
> level (no date provided),
> * historic=flood_mark - with information about flood event (with date)
> So existence of date on such mark could be a good information for proper
> tag assignment. I'm not familiar with tides, so please correct me if this
> is not the case.

High tide is defined as " the highest level which can be predicted to occur
under average meteorological conditions and any combination of astronomical

IMHO, the high tide mark as such shouldn't really be shown in OSM as it
should be the line marking either the coastline or riverbank.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tagging/attachments/20180808/2d4f40a5/attachment.html>

More information about the Tagging mailing list