[Tagging] Feature Proposal - RFC - Check dam

[Yves]

What I see when I look for pictures of check dams are structures that limit the flow. Contrary to what I expect from a weir, the water goes trough or under.
That would deserve a tag or subtag to make them distinct from weirs.
Regards,
Yves 

Le 7 juin 2021 23:28:02 GMT+02:00, Enno Hermann <enno.hermann at gmail.com> a écrit :
> <https://goo.gl/maps/PrtuW627ndkc3NbX7>
>
>On Mon, Jun 7, 2021 at 6:03 PM Mateusz Konieczny via Tagging <
>tagging at openstreetmap.org> wrote:
>
>>
>> https://wiki.openstreetmap.org/wiki/File:Check_dam_on_Miya_River_(Jinzu_River).jpg
>> for me it looks like waterway=weir
>>
>> "Solid check dams usually have water flowing over only a small part of
>> their width and
>> are designed to handle sudden increases in water flow."
>>
>> Are you sure that thing depicted on image is not also a weir?
>>
>
>I agree that it's not the best example and from this picture alone it could
>be hard to tell, although the construction is typical for check dams. I
>managed to find the location and on Google Streetview (
>https://goo.gl/maps/PrtuW627ndkc3NbX7) or the Japan GSI seamlessphoto
>imagery (https://osm.org/go/7QeF1CmI6) the water level is clearly different
>and water seems to be flowing only through the bottom of the structure.
>Given that, the mountainous terrain and similar structures nearby I would
>say it is clearly a check dam.
>
>
>> And "designed to handle sudden increases in water flow." is applicable to
>> any sanely constructed waterway engineering.
>>
>
>"sudden and significant" might fit better. Often those streams are normally
>only a trickle or even completely dry but then can see sudden debris flows
>like this: https://www.youtube.com/watch?v=2Rfuoylv34k This is different
>from floods on already larger rivers.
>
>
>> See
>> https://en.wikipedia.org/wiki/File:Culverts_under_yass_river_walkway_weir.JPG
>> on Wikipedia weir page.
>>
>> Or https://en.wikipedia.org/wiki/File:Grial%C3%ABces_cuecenes.jpg with
>> description
>> "During periods of high river flow, this nineteenth century weir of
>> porphyry stone on
>> a creek in the Alps would have significantly more water flowing over it."
>>
>
>An early example of a check dam? ;) I'd say very small structures or simple
>constructions that can't be clearly identified as a check dam may just be
>tagged as weirs.
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