[Tagging] Flood mark or high water mark

[Robert Szczepanek]

Hi all,

We work on flood marks project [13] and your opinion on proper tagging 
is crucial for us, as database of existing features is based on OSM 
records. We have identified probably most of existing marks in Poland, 
but would like to finally unify tagging within OSM project.

Both terms (flood mark and high water mark) can be treated as synonyms 
[1][2].
High water mark is more popular in USA [3][4], while flood mark in 
Europe [5][6]. But this is not a rule [7].

Why "flood mark" term is better in our opinion?
1. "Flood" term is shorter and easier to understand worldwide compared 
to "high water".
2. Flood mark is more popular in scientific publications [8, 9, 10]. 
References are from "Hydrology and Earth System Sciences", one of the 
best hydrological journals [11].
3. "High-water mark" term is used also in economy and has another 
meaning [12].
4. All additional keys usually contain "flood", not "high water" term. 
Like "flood_date". It will be more consistent.

In OSM database there are now:
- 262 features with flood_mark=yes [14]
- 80 features with historic=highwater_mark [16]
- 20 features with high_water_mark=yes [15]

Question 1:
a/ flood_mark
b/ high_water_mark
c/ highwater_mark

Question 2:
Which tagging convention should we follow:
a/ flood_mark=yes + historic=memorial + memorial:type=flood_mark
b/ historic=flood_mark + flood_mark:type=(plaque, painted, ...)
c/ historic=highwater_mark

Not every flood mark is a memorial, so probably 2.a/ is not the optimal 
option. Short discussion about this can be found here [17].

Thank you for help,
Robert


References
[1] http://floodlist.com/dealing-with-floods/flood-high-water-marks
[2] 
https://theconversation.com/historical-record-shows-these-floods-are-no-high-water-mark-23266
[3] https://www.weather.gov/gld/1935flood-hwmarks
[4] https://www.fema.gov/high-water-mark-initiative
[5] 
https://www.ceh.ac.uk/news-and-media/news/ceh-experts-contribute-environment-agency-report-feh-local-flood-frequency-estimation
[6] 
http://www.studia.photos/england/oxford-oxfordshire-england-uk/attachment/flood-marks-osney-lock-river-thames-oxford-oxfordshire-england-uk/
[7] 
https://www.alamy.com/stock-photo-flood-level-hight-marks-on-st-margarets-church-porch-kings-lynn-norfolk-11448961.html
[8] https://www.hydrol-earth-syst-sci.net/19/3517/2015/hess-19-3517-2015.pdf
[9] 
https://www.hydrol-earth-syst-sci-discuss.net/12/6541/2015/hessd-12-6541-2015.pdf
[10] 
https://www.hydrol-earth-syst-sci.net/18/4029/2014/hess-18-4029-2014.pdf
[11] https://www.scimagojr.com/journalsearch.php?q=hydrology
[12] https://www.investopedia.com/terms/h/highwatermark.asp
[13] http://openhydrology.org/maps/flood_mark/
[14] https://wiki.openstreetmap.org/wiki/Key:flood_mark
[15] https://wiki.openstreetmap.org/wiki/Key:high_water_mark
[16] https://wiki.openstreetmap.org/wiki/Tag:historic%3Dhighwater_mark
[17] https://wiki.openstreetmap.org/wiki/Talk:Tag:historic%3Dhighwater_mark