[Tagging] Drafting proposal: use oneway=reversible or create tag?

[moltonel 3x Combo]

On 07/09/2015, David Marchal <penegal at live.fr> wrote:
> I'm drafting a proposal concerning some waterways whose flow regularly
> changes direction, which happens near some sinkholes named estavelles, which
> drain or feed water according to the aquifer level. I would consequently
> propose a way to map it, but it should be consistent with current tags, so I
> wondered: should I propose using
> oneway=reversible, as it already exists and can be used on other ways than
> roads, according to the wiki, but would in this case be used to indicate
> that something is _not_ oneway, oranother tag, such as twoway=yes, which
> could be clearer in this context of a way you would expect to be oneway, but
> at the risk of duplicating the use of oneway=no?

Don't use oneway=*: it relates to the direction that vehicles (in this
case boats) are allowed to take, not to the waterflow.

I don't know of an existing tag. I've searched for 'flow' and
'up/downstream' in taginfo, but the only thing I found came from
imports and had very bad values from an OSM POV. Unless somebody has a
better Idea, I suggest creating a tag.
waterway:flow=forwards/backwards come to my mind, but that's an
endlessly bikeshedable topic.