The River Ouse

Over 750 miles of rivers

The Sussex River Ouse is a beautiful and fascinating network of over 750 miles of rivers, streams and brooks which collect water from just over 250 square miles of the surrounding countryside. The main River Ouse begins from springs near to Slaugham in West Sussex before flowing south east to Haywards Heath before meeting its main tributary, the River Uck, at Isfield. Feeder streams for the River Uck come from the north-east and south-east of Uckfield before meeting the main river. From their confluence (meeting point) the River Ouse flows southwards through Barcombe Mills to Lewes and finally meets the sea at Newhaven.


Map of the Sussex River Ouse catchment

Between 1790 and 1814 the river was straightened and deepened for navigation which eventually reached Balcombe, enabling the construction of the Balcombe viaduct during the 1840s (left). The legacy of the canalisation of the river is still evident today with many lock and weir structures present along its course. However, this legacy is also evident in the large structures which inhibit species from moving within and around the network of channels and create large sections of impounded (still) water along its length, which lack the habitat and oxygen to sustain a diversity and abundance of wildlife . Often during the summer, the main river is more akin to a series of elongated lakes rather than a majestic flowing river.

But move away from the main trunk of the river and it is often surprising to see how magnificent this waterway is. Gravel riffle and pool sequences are complemented by large woody debris structures, natural rock formations and gullies and a variety of plant life including water crowfoot and starworts. These habitats often support a diversity of freshwater invertebrates including mayflies, willow flies, freshwater shrimps, swan and pea mussels and some rare water beetles to name but a few.

The river is accessible in many areas via footpaths with the Ouse Valley Way a 67km walk from the quiet beginnings of Lower Beeding near Horsham to Newhaven and Seaford Bay taking in some of the best the river has to offer.

Support our work to protect and enhance the Sussex River Ouse by becoming a member, making a donation or signing up as a volunteer for one of our activities

The Ouse & Adur Rivers Trust


OART is a membership based organisation dedicated to the environmental protection and enhancement of the Sussex River Ouse and Adur including their tributaries, estuaries and still waters.

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The Ouse & Adur Rivers Trust (OART) is a registered charity (No: 1082447) formed in 2011 from the amalgamation of two long-standing local organisations, the River Adur Conservation Society and Sussex Ouse Conservation Society.