Weird River Things

they put these weird things in the rivers that I'm pretty sure prevent flooding, but they make for a really fun life-sized plinko board

Dad: I suspect they're designed to slow the river down (limit it's erosive potential in flood stage), but I don't know for sure...Confirmed. They're called "grade control structures." Purpose is to reduce bank and bed scour (erosion).

Boom. (drop the mike). They have so many flood prevention structures on the rivers here.