River Arun
River in England
The River Arun is a river in the English county of West Sussex. At 37 miles long, it is the longest river entirely in Sussex and one of the longest starting in Sussex after the River Medway, River Wey and River Mole. Wikipedia
Source: St Leonard's Forest
Length: 37 mi
Discharge: 168.8 ft³/s
Basin size: 376 sq mi (970 km2)
Designated: 16 December 1999
Towns: Horsham, Arundel, Littlehampton