I liked it particularly because it's neat looking without adding anything to the river that shouldn't be there, or taking anything away that belongs there. Also, it reminded me of New Zealand, in that I would occassionally encounter one or two stacks like this along rocky beaches.
There was a guy wading around and trying (mostly failing) to create new stacks. We didn't talk to him, and we couldn't tell if he had worked on the rest of them, or if he'd just come across it all and decided to try his hand at it.
I really need to carry my camera with me more often. I could have had much cooler photos if I'd had a zoom. And, you know, a better quality camera than my phone can offer.