christ alive that's a low head dam, those things have a feature at the bottom called a "drowning machine" DO NOT DO THIS
There is a great Practical Engineering video that explains this risk for anyone who is curious.
Crossing that dam was definitely a bad move.
He couldn't even stand there without being pushed off and it looks like he had regular shoes rather than clip in ones. I don't think different tires would be any different. Probably a nice slick layer of algae on there.
