Salt flats how is it tagged.

Like Bonneville Salt Flats

In winter a inch of water in summer dry.

Is it already rendered on the default map.

There was a discussion about this on the tagging mailing list in October. I don’t remember whether there was a consensus, but you might get some ideas from the discussion (intermittent vs. seasonal)

I searched further, Salar de Uyuni is a salt_flat

but using desert is strange

I liked to see it rendered on the default osm map.

I also put it on this site to render.