To cross a stream, street or valley (exactly where the delay because of a flight of locks at possibly facet might be unacceptable) the valley could be spanned by a navigable aqueduct – a well known illustration in Wales may be the Pontcysyllte Aqueduct (now a UNESCO Environment Heritage https://urso-fofo90009.shoutmyblog.com/36168859/considerations-to-know-about-musica-infantil