Previously known as the Sore, The Adur is a river in Sussex, England and gives its name to the Adur district of West Sussex. Over time the river valley became silted up and the port moved down to the deeper waters nearer the mouth in Shoreham-by-Sea. Formerly the river was navigable for large vessels up as far as Steyning, where there was a large port.
Based on the name of the Roman fort Portus Adurni which was mistakenly believed to be at Shoreham, the name Adur is a relatively recent (17th Century) invention.
The river is at its most interesting at mid-tide when half the mud flats are revealed. Especially during the colder months of winter, the mud flats become a roost for gulls and other birds. Birds and waders found here include Dunlins, Lapwing and Ringed Plover and Redshanks sound the first warning at the anticipation of danger. After feeding on eels and flatfish Cormorants fan their wings on boats and wooden posts.
The two separate branches of Adur, the eastern Adur and the western Adur, meet slightly west of Henfield at Betley Bridge. Before the early 1800s boats could navigate to Mock Bridge where the A281 crosses the Adur.
The eastern Adur is fed by the Cowfold Stream at Shermanbury and rises at Ditchling Common, in East Sussex, where it crosses into West Sussex and meets a major stream of Twineham. There is a footbridge near Shermanbury Church and the western Adur is tidal as far north as Bines Bridge close to Bines Green, south of West Grinstead.
Rising at Slinfold the western Adur flows around Coolham and then through Shipley, where it then meets Lancing Brook and flows on to Knepp Castle and West Grinstead.
The Baybridge Canal uses part of the Adur’s watercourse. From west of Henfield, the two river branches meet, before flowing between Bramber and Upper Beeding, past Coombes, through a gap near Lancing College in the South Downs where the Adur is fed by the Ladywell Stream. The river continues on to the English Channel at Shoreham-by-Sea. Due to longshore drift, the mouth of the Adur is now two miles (3 km) from the town centre of Shoreham. The town of Shoreham-by-Sea supports varied wildlife fauna and flora and being close to the River Adur and with the downs and the sea nearby.