why is the river severn called the river severn
With an average discharge of 107 mÂ³/s at Apperley, Gloucestershire, the Severn is the greatest river in terms of water flow in England and Wales. The river is usually considered to become the Severn Estuary after the Second Severn Crossing between Severn Beach, South Gloucestershire and Sudbrook, Monmouthshire.he Severn's drainage basin area is 4,409 square miles (11,419 km 2), excluding the River Wye and Bristol Avon which flow into the Severn Estuary.