To cross a stream, street or valley (exactly where the delay because of a flight of locks at possibly aspect will be unacceptable) the valley could be spanned by a navigable aqueduct – a renowned example in Wales is the Pontcysyllte Aqueduct (now a UNESCO Environment Heritage Web page) https://finnjjdws.bcbloggers.com/36192741/musica-infantil-can-be-fun-for-anyone