I’m leaving this photo a little large because it is difficult to figure out exactly what is going on here. There is a man lowered down into the ravine or spillway and he is doing…something…while a variety of other men look on from the safety of the bridge. I think the large pipe is an irrigation or drainage pipe, maybe one that diverts water from the roadway? The bridge doesn’t appear to cross that culvert, but instead travels over it lengthwise. It’s a mystery.