‘Rewiggle’ room: Lewes river channel project will create new wetland | Rivers

A chalk stream in Lewes, East Sussex, has been “rewiggled” to restore its natural flow and create a public wetland.

The Cockshut is a 1.9-mile long chalk stream that flows from the foot of the South Downs in Kingston, joining the River Ouse at Lewes before flowing out to sea.

Diggers last week broke through an artificial riverbank, allowing water from the chalk stream to rush into the 7-hectare (17-acre) wetland area.

The project forms part of a shared initiative by Lewes district council, Ouse and Adur Rivers Trust (OART) and Lewes Railway Land Wildlife Trust to rewiggle and realign the stream into a new channel, restoring its natural flow and reducing the risk of flooding.

Peter King, the director of the OART, said the new channel would “allow the water to move through the system a lot slower” and “increase the landscape’s capacity to hold water”.

There are only 220 chalk streams in the world, an estimated 85% of which are found in England. However, a high proportion have been negatively affected by human activities.

Alan Stewart, a professor of ecology at the University of Sussex, said past construction of straightened, artificial canals to transport vessels had increased the risk of flooding, noting that Lewes had a “devastating” flood in 2000. The flood destroyed about 100 properties, including homes and businesses, and led to six days of power cuts.

Stewart said removing artificial river banks and allowing streams to create their own natural winding courses was ultimately the most sensible approach to reducing flood risk.

King said the Cockshut chalk stream was a site of special scientific interest that had been in “unfavourable condition for a number of years due to the decreasing biodiversity across the site”.

According to Stewart, one of the most important outcomes of the project would be the removal of a large floating mat of parrot’s feather,, an invasive non-native plant that clogs up the stream, “outcompeting native aquatic plant species and reducing the oxygen in the water”.

An ecological impact assessment has forecast that the creation of the wetland will boost the population of rare mollusc and dragonfly species that live there.

There have already been reports of bird sightings by the channel. Emily O’Brien, a local councillor, said: “The UK is one of the most nature-depleted countries in the world, so to see birdlife already at the water’s edge and know that so much other life will soon follow, it’s incredibly exciting for everyone involved in this superb project.”

The total cost of the project is just under £500,000, with funding provided by bodies including the district council, South Down national park authority and the Veolia Environmental Trust.

According to King, the project is connected with other work by multiple partners to create new wetlands across the south coast of England and has been warmly welcomed by the local community.

The project will be completed and accessible to the public by this autumn.