Drop your most "wtf that's not how the world works" from movies/tv shows.
https://www.youtube.com/watch?v=EMBkWtDAPBY&t=1
Pre-Columbian Aqueduct around Cumbemayo, Peru
I think it is to reduce the speed at which the it flows.
Legitimately ugly rule
https://www.youtube.com/watch?v=EMBkWtDAPBY&t=1