This way is tag as a river. The problem is the beginning of this waterway is not a source but formed by a surface runoff (when there is enough rain).

So it's not clearly a stream nor a brook because there is no source but it still is a waterway. According to the wikipage of the brook tag, the description matches with this waterway but the tag is disputed and the wikipedia page of Stream says a brook is fed by a spring or a seep which is not the case here.

So, which tag should I use to describe it? Or, should I consider this waterway as an OSM way?

asked 20 May, 18:26

Pico51's gravatar image

accept rate: 0%

Drain is for artificial waterways. It's totally natural in this case.

(21 May, 07:37) Pico51

Why not waterway=stream? That's the widely-used tag for what you're describing. If there isn't always water flowing in it, then also add intermittent=yes.

(22 May, 17:01) alester

@alester It's because it is not clearly a stream. A stream must have a source and it's not the case here. This waterway is just composed of rain water.

(30 May, 12:55) Pico51

"A stream must have a source" Where are you seeing this requirement? Neither the OSM Wiki article for waterway=stream nor the Wikipedia article say this. In fact, there are multiple places in the Wikipedia article where it describes exactly what you're wanting to tag.

(30 May, 17:58) alester

@alester In France, there is a legal distinction between surface runoff and stream ; one of the three criteria to consider a "waterway" as a stream is the existence of a source. This distinction is important because it has some impact on local agricultural policy and I think it's important to think about it when we build a map.

(31 May, 19:06) Pico51

@Pico51: the correct way to map this on OSM is waterway=stream, probably with intermittent=yes. Specific rules to do with the French legal system need to be tagged in a different way. If we did the same with highways we would never have created a map usable across countries.

(31 May, 20:58) SK53 ♦
showing 5 of 6 show 1 more comments

I would not map surface runoff, everywhere is runoff when it rains isn't it? If the the area was always wet and boggy then map as marsh or wetland. Man made ditches are usually straight and on the edges of fields or natural brooks or streams can be mapped. If we were to map smaller than this the map would be all small blue threads wouldn't it? Many, maybe most streams and rivers in populated areas have over the years been rerouted for farm land drainage, irrigation, navigation and power for water mills. Staunching ( low dam ) and hand dug channels that lead a stream off, do after a few storms erode into something that will look natural. I would suggest that any river with locks or weirs is not natural even though i/we do map them as natural water.

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answered 10 Jun, 08:50

andy%20mackey's gravatar image

andy mackey
accept rate: 5%

Hi pico51, did you consider using natural=wetland as source of the stream since you stated it is not a brook. That’s what happening the water runs into the (grass) or rocky field and at a moment it is running as a little stream. With the appropriate tags for water running every now and then.

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answered 10 Jun, 00:22

Hendrikklaas's gravatar image

accept rate: 6%

I didn't know this tag but I think I can't use it here because it is a way and not an area :

(10 Jun, 18:29) Pico51

I think waterway=ditch may be the better tag. It's for simple, narrow, usually unlined artificial waterways used to drain land or remove stormwater.

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answered 01 Jun, 15:50

neuhausr's gravatar image

accept rate: 21%


I think waterway=ditch is used for artificial waterways but here @Pico51 is talking about a natural non-permanent waterway made of rain waters. I think the most appropriate tag is waterway=stream + intermittent=yes as mentioned in the comments above by @alester and @SK53.

(01 Jun, 16:19) Privatemajory

I don't see that @Pico51 has mentioned whether it's natural or non-natural. This is a distinction best figured out via survey so I don't know the definite right answer. However, one indicator of non-natural waterways via imagery is if a waterway has many straight segments and hard angles. This waterway looks much straighter and more angular than the stream Le Bonrupt to the northeast, which makes me suspect it's non-natural.

(01 Jun, 17:00) neuhausr

@Privatmajory : I thought the artificial form was called drain and that ditch is rather natural.

(01 Jun, 21:52) escada

@escada: on the wiki, waterway=drain and waterway=ditch are both artificial, and the difference is mostly size (also possibly lining). That seems to have been the definition since at least 2011.

(01 Jun, 22:03) neuhausr

@neuhausr It's definitely a natural waterway. It starts inside a field and the water is carried by the ground until the road. I guess the best definition for it is waterway=brook but it is marked as disputed so I don't know if it's a good idea to use it.

(02 Jun, 13:57) Pico51

@pico51: there is no real difference in british english between stream and brook. There are numerous other words used in english for streams (gill, beck, burn, water). Where I live most streams have "Brook" in their name. Therefore trying to introduce some semantic difference between waterway=stream and waterway=brook in OSM is rather foolhardy.

The correct way forward is to add one or more additional tags to handle the situation of surface runoff. A fairly obvious option would be to specify the water source: assuming the default to be groundwater (i.e., arising from a spring) and therefore not needing tagging, some options might be surface_runoff, glacial_meltwater, cave_system (for subterranean waterways in karst landscapes), etc.

(02 Jun, 18:25) SK53 ♦

I am interested, how did you map the first 400 metres i can't see anything on bing or digital globe other than what looks like cultivated farmland. The next section seems to follow what appears to be a ditch with vegetation or hedgerow which may not be natural as the sections look angular rather than curved like natural brooks or streams

(03 Jun, 11:15) andy mackey

When the "water" crosses the Voie de Battexey à Hergugney is there a ford, a bridge or a culvert?

(03 Jun, 11:21) andy mackey

@SK53 I agree with that idea but there is no options like surface_runoff in the tag water_source who is generally used for fire hydrant.

(09 Jun, 14:24) Pico51

@andy-mackey The drawing is not exact for the moment but the 400 first meters are correct. If you don't see anything on satellite image, it's the reason of my question: it is a surface runoff made by water rain who follows the depression in the ground. There is water just when it rains and few days after (if the ground can't absorb it).

(09 Jun, 14:27) Pico51
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question asked: 20 May, 18:26

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last updated: 10 Jun, 18:29

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