Question is does it mean water in any of the three states, solid, liquid, vapor? I'm guessing strictly speaking it does. Naturally cloudy skies this week.
Grand canyon, many kinds of errosion, sand rippled by previous waves, glacier scraped hill, house knocked off foundations by flood, polished river stones, caked dirt on hand half washed off, rusted anything, ... .
I agree with jnenvir and bob350. I think any phase of water is not to be included and the challenge is about the "footprint" so to speak, that it leaves behind.
