A man was left clinging to the side of a bank after falling into a village stream.
Emergency services were called to Frylands Lane in Wineham after the 70-year-old fell into a tributary of the River Adur at 12.40pm.
Police said the Hove resident was found clinging to a bank beside a wooden footbridge with water up to his chest. He was unable to climb out of the water due to his heavy clothing.
Officers managed to rescue him and pulled the pensioner from the water at about 1pm.
Firefighters arrived soon after and helped carry the man across a field to be treated by paramedics.
He was checked over at the scene before being taken to the Princess Royal Hospital, in Haywards Heath, with a head injury.