Well, I guess it is kinda hard to work on a bridge with tons of water and debris flying at you.

Well, I guess it is kinda hard to work on a bridge with tons of water and debris flying at you. (These are primarily pedestrian bridges and they do need work. Because you know what's really bad for tourism? Killing tourists if a bridge collapses under them.)
http://www.thestar.com/news/canada/2016/01/25/us-officials-may-temporarily-turn-part-of-niagara-falls-into-trickle.html
http://www.thestar.com/news/canada/2016/01/25/us-officials-may-temporarily-turn-part-of-niagara-falls-into-trickle.html