Shadow does this to. We have an elevated feeder in the kitchen with a bath mat under it, to soak up her spills. Shadow will also take a mouthful of water and walk threw the kitchen into the lounge room dripping water every where.
Thank goodness we don't have carpet. I always thought it was all about keeping their body temps down as well, because I've noticed it's worse after she has done a lot of running around.
I wouldn't bother with the rock, it just gives them something now to dive and dig at. Shadow dumps rocks, balls, toys etc into her water- perhaps they need cooling off to.
