What if there was a lake on the Moon?
... Because of the reduced gravity on the Moon, the water would be launched upward more easily, just like the swimmers. The result would be larger waves and more flying droplets. In technical terms, a pool on the Moon would be more "splashy".
To avoid splashing all the water out, you'd want to design the deck so water drains quickly back into the pool. You could just make the rim higher, but then you'd spoil one of the key joys of a pool on the Moon—exiting via Slip 'N Slide.
I love XKCD.