A lot of people don't realize this, but Diana often goes days and sometimes weeks without showering or bathing. Obviously Superman suffers the most due to his supersmell ability. He decided to make sure Diana gets clean and stays clean for a while, and this is the result.
That actually was a problem when I started the image, because I was originally going to make the water all murky and dark. But, well, nothing but unfortunate thoughts crossed my mind and both myself and the guys in the stream were very "myeeeehhh" about brown water. So there was a change in direction, and I made the water clear and only semi greenish-milky in hue. I like to think this is "incoming" water, not outgoing.