To cross a stream, street or valley (the place the delay caused by a flight of locks at possibly side would be unacceptable) the valley is usually spanned by a navigable aqueduct – a well-known instance in Wales could be the Pontcysyllte Aqueduct (now a UNESCO World Heritage Web https://canalinfantil55442.rimmablog.com/36105380/rumored-buzz-on-canal-infantil