How to map a Dam Plug Hole

Not sure if the term is correct, however I want to know how to map the plug hole in the dams, where the rivers continue its way out of the reservoir.

I have found one mapped as a building, but it has validation warnings.

What is the appropriate way to map them?

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The point where waterway=canal + usage=spillway (+ tunnel=culvert ) connects: Tag:inlet=bell_mouth - OpenStreetMap Wiki
The area: natural=water + water=canal + usage=spillway + intermittent=yes (not yet mentioned but has ~360 instances, supposedly applicable on bellmouths as well; it’s truthful tagging to care for renderer)


Those are called “intake towers” (Wikipedia), and search on OSM Wiki reveals Tag:tower:type=intake, which suggests:


…however, as Kovoschiz suggested, it’s a bit strange that there is no relationship with inlet, since an intake tower and a bell mouth serve a similar purpose. I would expect something like inlet=tower as an additional tag that specifies a beginning of the adjacent man_made=pipeline.

P.S. Now I realized that the Andres’s image features both an intake tower and a bell mouth. As Wikipedia explains, intake tower (in the background) is used to ingest clear, debris-free water, and direct it to a pressurised pipeline leading to the turbine or a water-processing facility. In contrast, a bell mouth (in the foreground) and only drains the excess surface water into an open-air spillway (canal=spillway). See Spillway - Wikipedia .

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