To cross a stream, street or valley (where the delay due to a flight of locks at both facet could well be unacceptable) the valley could be spanned by a navigable aqueduct – a famous instance in Wales is definitely the Pontcysyllte Aqueduct (now a UNESCO Environment Heritage Website) https://musicainfantil98776.vidublog.com/36060167/indicators-on-canal-infantil-you-should-know