To cross a stream, highway or valley (exactly where the hold off brought on by a flight of locks at either side will be unacceptable) the valley might be spanned by a navigable aqueduct – a well known illustration in Wales is definitely the Pontcysyllte Aqueduct (now a UNESCO https://stepheniptzd.p2blogs.com/35822354/the-single-best-strategy-to-use-for-musica-infantil