Talk:Proposed features/Hydropower water supplies

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Bad use of waterway key

Please don't use the waterway key for anything that is not strictly free surface waterflow. Especially do not use waterway=drain (or other existing waterway tags) for pressure tubes. This would make life quite difficult for many data users and would unnecessarily blur the meaning of tags used quite consistently in that regard at the moment. --Imagico (talk) 17:34, 2 December 2017 (UTC)

The proposal may be miswritten, but I don't change definitions of existing values. My point is man_made=pipeline is not enough to get an accurate water topology.
waterway=drain is not used for high pressure tubes at all. But, as any confined space where water flows, it can be designed to bear a small pressure or not (pipe flow vs free-space flow). Typically, assuming an underground storm drain is only designed for free-surface flowing is wrong. And I don't see any compatibility issue between waterway=drain, location=underground and tunnel=culvert got waterway=* as useful combination on current wiki.
Furthermore, a tunnel is not a pipeline, then what other values than waterway=drain should be used for pipe-flow water tunnels ? Fanfouer (talk) 10:52, 3 December 2017 (UTC)
The distinction between free surface water flow (German: Freispiegelleitung) and pressure tubes (German: Druckrohrleitung) for covered/tubed water lines is both a commonly well identifiable distinction for mappers and an important distinction in hydraulic engineering. And as said it is an important distinction for data users.
man_made=pipeline + substance=water + usage=penstock seems perfectly sufficient for tagging such pressure tubes. Key:waterway does not specifically mention free surface water flow but with a flow of water from one place to another quite clearly implies free surface water flow.
I get your point about the importance of these features for the global hydrographic system but i think you miss that while some penstocks represent a water path in that systems others don't - like http://www.openstreetmap.org/way/351499334. Because of the widespread abuse of waterway=canal + tunnel=yes using waterway=penstock would indeed be an improvement - but it would not solve the problem of mapping the hydrographic meaning of such pipelines, i.e. if they channel a pre-existing natural waterflow locally into a pressure tube or if they divert water into a completely different flow regime.
The way of mapping that currently is probably best in line with established mapping practice is to include the penstock in the waterway relation. This is usually very clear in meaning.
Something to keep in mind in case of dams - you can argue that the spillway is actually what fulfills the function in the hydrographic system, not the penstock. Of course not all dams have a spillway. --Imagico (talk) 11:35, 3 December 2017 (UTC)
I agree on the need of distinction, but it doesn't require to dedicate a common word as waterway for a single of both.
Not all penstocks are pipelines, a tunnel isn't a pipeline. waterway=penstock nor waterway=drain doesn't strictly imply man_made=pipeline.
I don't get the free flowing implication from with a flow of water from one place to another. Could you elaborate a bit more please?
Importance is a business we can take care about once features are well identified. As you said, water channelization can't be accurately done in OSM and we need values (not keys) to improve this. Anyway, flowing water amount inside a penstock can't be add to OSM since is a variable data.
I'll add a mention to the proposal to add penstocks and feeding tunnels to waterway relations
Regarding dams, it's also in waterway=* key and not in man_made=*. Then it would be nice to add at least a waterway=stream on the spliiway. I allways add water path around dams, like this : https://www.openstreetmap.org/way/543378764 Fanfouer (talk) 14:15, 3 December 2017 (UTC)
Mapping such features, I could not find adequate tags and I think that this proposition is interesting to characterise waterway deviations for power stations. I dont think that anyone would argue that motorways in a tunnel are not free surface circulation. It should be the same for waterway sections that are derived in a tunnel. This is part of the hydrographic system but with particular characteristics to describe. Man_made should be for features who are not part of the hydrographic system. pierzen (talk) 14:23, 3 December 2017 (UTC)
man_made=pipeline does not imply tubing. The tag documentation specifically mentions underground pipelines which in rocky ground usually don't use tubing.
I cannot really prove that Key:waterway implies free surface water flow but it is clear that most mappers consider this implied. Anyway - i don't really mind if you create a tag specifically meant for water transport that is not based on free surface flow with the waterway key. But please don't blur existing tags that are almost exclusively used for free surface flow at the moment (waterway=drain) by adding that they can also be used for other things. This would massively devalue existing data. --Imagico (talk) 14:55, 3 December 2017 (UTC)
Fine, I thought using waterway=drain would ease adoption but I understand this would cause some issues with existing data.
Nevertheless, there are tunnels with free flowing and tunnels designed for pipe flowing. Can I go on with waterway=drain for free flowing and waterway=pipe for pipe flowing? This would be suitable for siphons too.
Regarding man_made=pipeline, given problem is it's not a water specific key, and consumer looking for waterway=* only to get water topology will miss some edges in the graph.Fanfouer (talk) 15:44, 3 December 2017 (UTC)
The waterway class is usually a matter of function and size. A tunneled section of any waterway gets a tunnel=yes. It does not change the waterway type. But if you funnel the water of a stream or drain into a pipe in my book it is not a waterway any more, it is a pipeline.
For data consumers i see no problem for filtering for man_made=pipeline + substance=water in addition to waterways. But as said if you prefer i have no big problem with waterway=penstock or waterway=pipe as long as it is well defined what this is supposed to mean.--Imagico (talk) 16:53, 3 December 2017 (UTC)
I've moved the proposal towards waterway=duct for both horizontal tunnels and penstocks. As you said, it's good to use man_made=pipeline + usage=penstock. It's important for me to have waterway=* on each segment. is it better now ? Fanfouer (talk) 17:27, 5 December 2017 (UTC)
The idea you want to implement seems to be that large volume encased water flows should get a common tag, independent of if they are pressure tubes or tunneled free surface flow and independent of if they are encased naturally flowing water or artificial. If you use the waterway key you remove the possibility to indicate these aspects since you cannot also tag them waterway=stream or waterway=drain for example - waterway=duct seems to be kind of waterway=artificial_or_natural_in_tunnel_or_pressure_tube and that would not work since it would overlap with all existing waterway types.
So - if you want to use something like waterway=penstock, waterway=pipe or waterway=duct that should be for pressure tubes only since for encased waterways with free surface flow we already have widely used existing waterway=* + tunnel=yes. --Imagico (talk) 17:56, 5 December 2017 (UTC)
The current situation is:
Separating out a new waterway class from the last with waterway=penstock, waterway=pipe or waterway=duct is not necessarily a bad idea - but that should not cut into the first four cases - which are widely used in the described meaning.--Imagico (talk) 18:43, 5 December 2017 (UTC)
I'm almost ok with this, waterway=duct would only cover pressurized pipe flow water paths. I find tunnel=yes akward since it implies for me that human can go inside. tunnel=culvert means the tunnel is flooded and dangerous for human even if the water flows freely. But tunnel=culvert sounds to be as short as drains under roads and won't be suitable for 10km long tunnels through mountains for water transmission, don't you?
Restricting waterway=duct to pipe flow is really an advantage to distinguish penstocks/siphons from drains. I'll update proposal to write this. Fanfouer (talk) 22:18, 5 December 2017 (UTC)

Add penstocks and tunnels to waterway relation

Regarding this particular remark, it's sometimes not possible to add penstocks and tunnels to waterway relation, since power operator doesn't release water to the river it took from.
Water can flow dozen of kilometers before power plant facility and be released in a different watershed.
If not, no problem to add man made facilities to waterway relation Fanfouer (talk) 16:24, 3 December 2017 (UTC)

Obviously only features that are part of a river may be added to the waterway relation. If you have a pipeline diverting water from a river to somewhere else this is of course not part of the river. The purpose of adding penstocks to a waterway relation would be to document they are a functional part of the river.--Imagico (talk) 16:56, 3 December 2017 (UTC)

Add infrastructures to regulate and deviate the water flow for Power Plants and Water Distribution

Add Dams, Weirs, Floodgates, Spillway and Fish Ladders as Waterway Relation Roles

To complete the Waterway schema and the Waterway relations, Water Management infrastructures to regulate and deviate water for power plants, water distribution or to protect some animal species should be added as waterway features.

Below are some Water Management infrastuctures not yet documented in a wiki page. This could probably be completed by other water managements to have a more complete waterway schema.

Floodgates are adjustable gates used to control water flow in flood barriers, reservoir, river, stream, There are 167 occurences waterway=floodgate in OSM ( See Wikipedia:Floodgate).

Spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically the riverbed of the dammed river itself. It can also be used to deviate water in an other riverbed. There are 114 occurences of waterway=spillway in OSM (See Wikipedia:Spillway).

A fish ladder, also known as a fishway, fish pass or fish steps, is a structure on or around artificial and natural barriers (such as dams, locks and waterfalls) to facilitate diadromous fishes' natural migration. There are 44 occurences of fish_pass (See Wikipedia:Fish ladder). pierzen (talk) 19:47, 5 December 2017 (UTC)

Hi Pierzen and thak you for such comments.
I wonder if we should continue to add man made structures as waterway features like dams, floodgates, weir... Those features are a great value added to OSM, but they are not actual waterways
Nevertheless, ok to define particular waterway=spillway since, it's not a proper river or stream and map a significant danger.
Also ok for waterway=fish_pass since there are always water flowing to allow fish passing the dam or weir. Fanfouer (talk) 22:18, 5 December 2017 (UTC)
Hi Fanfouer,
Ðo you suggest that all Water Management infrastructures should be in a distinct schema, not integrated with waterways ? pierzen (talk) 22:48, 5 December 2017 (UTC)
Yes, I would put dam, weir, lock_gate, dock in different keys than waterway=*. This is mainly man made structures. But this is out of the scope of this proposal. I'll only add the features you've suggested like spillway and fish_pass Fanfouer (talk) 23:36, 5 December 2017 (UTC)
My understanding, to represent the waterbed and the water management the Waterway relation should include all the water management facilities. pierzen (talk) 23:47, 5 December 2017 (UTC)
I agree regarding the relation membership and this doesn't force dams, weir, gates to be part of waterway=* key.
I'll only refine relation membership of features this proposal add or modify. This will eventually need further work in another opus. Fanfouer (talk) 00:02, 6 December 2017 (UTC)