Hi. I have seen it a couple of times carved in a tree. It was used as a directional sign pointing the way to a tree carving site. IMHO, not a water glyph, because it was used along a creek bank, and clearly pointed downstream.
However, with that said, out west I've heard trackers say that's what it is. Supposedly used by the Aztecs or some other unidentified ancient people. Dan Dillman shows how it was used in Utah using his grandfather's research, on "Search for Aztec Gold" a TV series found on the Discovery channel. I have also read about other finds of the symbol out west sometimes carved multiple times in the same area.