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Hello, there.

I have a question about springs feeding water bodies and streams: if I have to map a lake, known for being feeded by a stream but not knowing where it is exactly beneath the surface, should I map the spring in the lake anyway, even if the location is vague? More important, if the water body in turn feeds a stream, should I map the relation between the spring, even inaccurately located, and the stream? Should I map the water body as the source of the stream? Start the stream at the border of the lake? Should I include the water body in the waterway relation, as it feeds the stream and can be considered as its source?

Awaiting your answers,


asked 09 Sep '15, 19:55

Penegal's gravatar image

accept rate: 0%

Hi Penegal, the river Aare flows into the Thunsersee and the stream is drawn completely from entrance to exit; Use that method. Since you don’t know where the spring actually is situated on the bottom of the lake, start the stream in the middle of the lake and into the river stream. All water parts are connected by the river stream read these lines;

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answered 09 Sep '15, 22:06

Hendrikklaas's gravatar image

accept rate: 5%

So, if I correctly understand, I shouldn't bother with the spring in the case it's at an unknown location in the lake?

(10 Sep '15, 09:28) Penegal

You should take a fictive point in the lake, yes or use the exit as a starting point of the stream, the practical starting point of the stream. Its visible that the water starts to flow there. There even could be several springs at the bottom of the lake. The lake gets natural=water and a name tag. The stream is the connecting element (way) for all the elements downstreams.

(10 Sep '15, 09:56) Hendrikklaas

According to the wiki, natural=spring is "a point where water flows to the surface of the earth from underground", so an underwater spring that feeds a lake doesn't seem to be the intent of the tag.

(10 Sep '15, 14:57) neuhausr

@neuhausr: well, technically, a spring in a lake still let the water flow to the surface of the earth, as the surface of the earth is under the surface of the water, at the bottom of the lake, so it could also be mapped as natural=spring.

@Hendrikklaas: so it's only when I put the origin of the stream in the lake that I should map a spring, even with an inaccurate location; if I put the origin of the stream on the lake border, no spring required, which is logical as, this way, the lake is the origin. The choice between the possibilities is mine, depending of the current knowledge of the lake.

Bonus question: should I include the spring in the waterway relation or only the waterways?

(10 Sep '15, 15:54) Penegal

you can tag it however you want. my point is when people are looking at features tagged natural=spring, it's unlikely they're going to expect it to be at the bottom of a lake.

(10 Sep '15, 16:01) neuhausr

Penegal, I would not do so I only map a spring like this a builded mouth of the river Schelde / L'escaut or the sources of the Meuse, both are marked with a stone, Both sources of the Meuse are on the Plateau of Langres and several French rivers are born here, such as the Seine, Saone, Marne and La Moselle.

(10 Sep '15, 21:44) Hendrikklaas

@neuhausr: I agree with you, people won't expect that, but, as it's a possibility that a spring is in a lake, I prefer keeping this in mind, not for all underwater springs, but for the cases it's somehow significant.

@Hendrikklaas: OK, then I won't link the spring with the waterway if the first feeds a lake first, should I have to map a spring in a lake.

And concerning the matter of including the spring in the waterway relation, I had my answer by the wiki: it's optional. Thanks for your help!

(11 Sep '15, 12:40) Penegal

Springs are actually known to be quite common in natural lakes. The majority of "springs" are actually groups of springs more like springs "fields".

The water source for springs is obviously ground water AKA the water table, an aquifer, an underground river or stream; all those terms describe water below the surface of the earth which is typically flowing at some rate through cracks, crevices, faults, channels and/or caves but also generally permeating the surrounding area, as water does, although it's flow is blocked off on at least one side (below; otherwise it wouldn't be springing up OUT of the ground!) if not on several sides by relatively impermeable material such as rock, clay or other mineral deposits.

I am surprised to learn that people in some areas do not associate springs with lakes. Those two words appear together in place names with great frequency. I don't think that most people expect most springs to be anything but the underwater source of a lake or pool.

(16 Dec '18, 18:53) JonP_75
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question asked: 09 Sep '15, 19:55

question was seen: 4,075 times

last updated: 16 Dec '18, 18:53

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum