River Wandle access works set to be improved with weeks of work

The Wandle Trail will be improved as Thames Water carries out the work on the Mitcham stretch of the River Wandle.

The works hope to improve biodiversity conditions on the rare South London chalk stream.

While preparatory works began last summer, efforts to lower the Goat Bridge Weir near Beddington Corner began on Monday (June 17).

Thames Water has warned the public that some noise and disturbance could be expected during this period but mainly along the Mitcham section of the Wandle Trail.

Lowering Goat Bridge Weir will allow fish and other aquatic life to swim on uninterrupted.

Thames Water has also warned that the section of the river downstream from the works could become murky at times.

However, it insists that any excess of silt caused by the works will be managed and overseen by the Environment Agency with conditions monitored throughout.

Thames Water has taken efforts to assuage flood risk fears and has even suggested that these works will reduce the number of properties at risk of flooding.

The presence of wetlands and low river banks means some stretches of the Wandle are prone to flooding, but Thames Water says "the number of properties affected by a once in 20-year flooding event would be cut by 95 per cent" as a result of the works.

More flood storage space and a wetlands area will be created alongside the river.

The land used for this has been provided by Sutton Council, an official partner of the project.

Weirs can be natural or manmade barriers which can cause rivers to break up into isolated sections.

The South East Rivers Trust (SERT), who are partnering with Thames Water on this project, acknowledge that weirs obstruct the natural flow of a river.

SERT told the Local Democracy Reporting Service (LDRS): “Weirs impound (restrict) rivers, breaking them into sections, leaving them like slow-moving ponds.

"Silt lies on the riverbeds, preventing fish from laying eggs. Downstream from a weir, the water is starved of sediment and gravel, making these areas less suitable for wildlife.

“Fragmented rivers are also less resilient to pollution incidents because wildlife might not be able to escape to other sections of water. Free-flowing rivers transport sediment such as silt and gravel continually.

"This process of being washed away and deposited in other areas creates the diverse range of habitats that aquatic wildlife need to thrive.”

The Goat Bridge Weir currently restricts about 500 metres of river, creating conditions more akin to a lake.

Wandle expert Dr Jack Hogan believes this work is essential to protect the Wandle’s status as a biodiversity hotspot.

Speaking to the LDRS, Hogan said: “Salmonids, like Trout and coarse fish, will be able to pass up and downstream. It will reconnect two bits of habitat and also enhance the habitat in the immediate area upstream where the weir is impounding it.

“The restoration work that SERT did in Hackbridge in 2014, which is a real biodiversity hotspot of the river, is now going to be ecologically connected to what is downstream.”

Hogan told the LDRS how access to the Wandle Trail, a footpath running along the river, is currently restricted along the Goat Bridge section.

He believes access to the river will be improved as a result of the works.

He said: “As it runs at the moment, the Wandle Trail is separated from the river by the site of an old factory. The factory was run by a company called Jura Spray before it was knocked down.

“As I understand, a new pocket park will replace that old site once the works are complete. That is going to increase access to the river and amenity value and a lot more attractive than when there was a big old building that stank of solvent all the time.”

Hogan, who has grown up around the Wandle, believes it is a special river that must be protected in the face of pollution and neglect.

He told the LDRS: “The Wandle is an incredible chalk stream. Even of all the chalk streams, the Wandle is unique.

"Every measure of help you can give to that river, to return it to its natural process, is going to do good for the river.

“One day the hope is that all of the barriers are going to be out of the way. Personally, I’d love to see us getting to the point with the Wandle were can imagine the return of migratory fish.”

The Wandle has played a significant role throughout history due to the course it sets from the Thames to the outer boroughs of London.

The river is particularly famous for its association with the textile designer and activist William Morris.

According to SERT: “In Victorian times, the Wandle was one of the world’s most intensively exploited rivers for industrial purposes: 90 mills were constructed along its 11-mile flow from Croydon and Carshalton to where it meets the Thames at Wandsworth.

“The river’s natural form was altered by this industrial age. It was straightened and deepened to enable development. The river’s clean water was used to manufacture a range of products including paper, gunpowder, dyes, copper and leather.

“Chemical waste dispersed from various industries left a rainbow of unnatural colours in the river.

"In the 1960s, this globally rare chalk stream was officially declared a sewer.”

Thames Water is required to deliver the program as part of the Water Industry National Environment Program (WINEP).

This is because Thames Water are extracting water from the Wandle.

In December 2023, the LDRS reported how Thames Water admitted that works to protect the River Wandle from sewage may not take place until 2035.

This came following the official apology from water companies in May, when they admitted to not acting quickly enough on previous sewage spills but vowed to put things right.