Emergency services were scrambled out after a call came through of reports of a person in the water at Acle.
The Norwich Air Ambulance was called out at 12:38 along with the fire, police and ambulance service, Hemsby Broads Rescue and Gorleston ILB were also on scene.
A spokesperson for HM Coastguard Gorleston said: 'Once on scene the casualty was in safe hands of the Air Ambulance Crew.'
A spokesperson for the East of England Ambulance Service Trust (EEAST) said they were called to reports that a woman had fallen from a boat into the river.
They added that when they arrived she was out of the water but had a very serious leg injury and had to be flown to the Norfolk and Norwich University Hospital for treatment.
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