Talk:Tag:man made=outfall

outfall location

While it's usually possible to determine the outfall location by inspecting geometries, including it as a tag makes it easier for data consumers to know the outfall location. Possible values could include waterway, ocean, lake. Perhaps outfall:location=waterway/ocean/lake Aharvey (talk) 23:16, 15 January 2025 (UTC)

Hello, I'd prefer to consider outfall:downstream=* or even more generic outlet:downstream=* to describe all outlets. The same could apply for inlets: inlet:upstream=*. Fanfouer (talk) 13:59, 19 January 2025 (UTC)

*:downstream=* resembles *:forward=* , that it means the what outfall=* is downstream. downstream=* doesn't exactly describe what it should be used for.
—— Kovposch (talk) 08:08, 20 January 2025 (UTC)

destination=* is already used on type=waterway , which was oddly voted through https://wiki.openstreetmap.org/w/index.php?oldid=766559#Tagging
Would have preferred generic from=* & to=* , when destination=* is signposted navigation. In either case, suggest *:water=* to follow water=* list. No need to invent another *:location=* here again.
But water_source=* already exists. The opposite should be water_sink=* ???
—— Kovposch (talk) 08:03, 20 January 2025 (UTC)

My motivation was to distinguish wastewater/sewage deep water ocean outfalls (far offshore) 10558559544 10558559544, from those that discharge directly at the shoreline 9503752953 9503752953, from those that discharge further upstream into a waterway 3806505254 3806505254 that then flows into the ocean. But I realise it's not that simple and this needs more thought. water_sink=* could work but we don't want to confuse it with a sinkhole. Aharvey (talk) 04:53, 21 January 2025 (UTC)

Ok sorry water_sink=* was a joke. I laughed at the possibility of water_sink=* being a kitchen sink, or washing basin more. But having a water_*=* somehow should be the best to follow water_source=* together. water_destination=* ? water_reception=* ??? The term to refer to where outfalls discharge to is the "receiving" waterbody.
discharge=* is measuring water flow, and some monitoring:discharge=* exists. Maybe it's not the best word.
—— Kovposch (talk) 17:19, 21 January 2025 (UTC)

Limitation on wording and use

"Outfall" can refer to either the discharge point, or the pipes and culverts themselves. This naming is unfortunate. With only ~30 when documented in 2021, and <1k now, it seems weak.
Outfall is often a diffuser, a row ("line source" in plume dispersion terms) or array of individual discharge. Restricting man_made=outfall to points doesn't make it easy and characteristic, but lines will conflict with the man_made=pipeline , showing the problem. https://www.flickr.com/photos/mitopencourseware/3228587203 (CC By-NC-SA 2.0)
https://www.mwra.com/your-sewer-system/sewer-treatment-facilities/deer-island-wastewater-treatment-plant/massachusetts
In fact, a diffuser cap with a ring of holes can be used, not only a simple upward discharge pipe https://www.mwra.com/sites/default/files/styles/large/public/2023-11/diffuser.jpg
—— Kovposch (talk) 08:16, 20 January 2025 (UTC)

I agree that tagging as a node, linear way or area way should be acceptable and therefore would also need area=* to distinguish linear/area ways. However I think the definition given here as the discharge point is sensible. So it would not cover the undersea pipe carrying the wastewater out to sea, it would just be the points or area where the wastewater is being directly discharged into the sea. Aharvey (talk) 05:00, 21 January 2025 (UTC)