Complex sentence: The Severn is the longest river in the United Kingdom, at about and with an average discharge of 107 m³/s at Apperley, Gloucestershire, it is the greatest river in terms of water flow in England and Wales.
Split into simpler sentences: The Severn is the longest river in the United Kingdom, at about. With an average discharge of 107 m³/s at Apperley, Gloucestershire, the Severn is the greatest river in terms of water flow in England and Wales.