To cross a stream, highway or valley (where the delay caused by a flight of locks at possibly facet might be unacceptable) the valley is often spanned by a navigable aqueduct – a well-known example in Wales will be the Pontcysyllte Aqueduct (now a UNESCO Globe Heritage Website) through https://zanderjrwch.blogolize.com/urso-fofo-things-to-know-before-you-buy-76132893