To cross a stream, street or valley (exactly where the hold off brought on by a flight of locks at either facet will be unacceptable) the valley could be spanned by a navigable aqueduct – a well-known illustration in Wales is the Pontcysyllte Aqueduct (now a UNESCO Entire world https://edgarfqyfj.bloggosite.com/44418430/helping-the-others-realize-the-advantages-of-urso-fofo