To cross a stream, highway or valley (in which the delay brought on by a flight of locks at either facet will be unacceptable) the valley can be spanned by a navigable aqueduct – a famed illustration in Wales could be the Pontcysyllte Aqueduct (now a UNESCO World Heritage https://backlinks18530.fare-blog.com/37374624/the-2-minute-rule-for-urso-fofo