Works are nearly complete on a ‘game-changing’ river project along one of London’s most important rivers.

Project leaders are now calling on volunteers to undertake conservation work along the river banks to help “nature return” to that stretch of the River Wandle.

The South East Rivers Trust (SERT) has been carrying out works on the Mitcham stretch of the River Wandle for the past 10 weeks.

The project, carried out by a group of partners including landowners Sutton Council, aims to improve the health of the rare chalk stream river and renaturalise the area for public use.

The project is focused on lowering the Goat Bridge Weir in Mitcham, which previously restricted about 500 metres of river, creating conditions more akin to a lake.

This meant the flow of the river was obstructed, leading to stagnant pools of water where pollution thrives.

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

During a visit to the site last week, Hogan told the local democracy reporting service (LDRS) of some of the surprising things the project team had found whilst working in the river.

Hogan told the LDRS: “We’ve found a lawnmower, a couple of fridges and even a motorbike in there. This stretch of the river was in a pretty poor state.”

The river’s course has been diverted around the weir throughout the 14-week project and is expected to return to its normal path through the newly lowered weir next week.

 While the lowering of the weir has taken place downstream, the team have taken to creating rocky berms along the stretch of the river to give it a more natural bend. 

To create the berms, the team raised alternating sides of the river bed to create bends, which allowed the river to flow where it was previously stagnant. 

According to SERT: “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.

Hogan believes the measures taken by the team are now allowing aquatic life to return to the river.

Hogan told the LDRS: “Almost immediately after these berms went in, five or six trout were seen investigating the new ripples in the water. 

“That wouldn’t have happened before, there was no moving water it was all slack and dead.

"Before the beds were black, and now there’s stream power it’s clearing that central way and cleaning it up."

Hogan’s enthusiasm for the project is infectious, and he was keen to stress how the work would have long-term benefits for the local Mitcham and Beddington community as well as wildlife.

He told the LDRS: “We’re actually seeing the river being reborn. It may look messy now but a year down the line it’s going to be looking gorgeous.

“I spent an hour talking to people down here the other day, and people were moaning and saying they’ve ruined the river.

"They need to understand that it’s two months of disturbance for hundreds of years of it being abundant.”

This sentiment is shared by local angler Amie Battams, who has fished on the Wandle her whole life.

Battams also documents the health of the river on her YouTube channel, “Amie Fly Fish.” 

She told the LDRS: “I’m so excited because they’re providing brand new habitat for every single fish species in the Wandle. 

“This is going to positively affect the bird life, plant life and everything that lives underneath the river.

"Only good things can happen with this, it’s going to change everything. It’s been damaged for so long and now it’s going to have a new lease of life.”

Alongside its work in the river bed, the team behind Goat Bridge Project also aim to improve flood defences in the area.

A large overgrown area just off the river bank has been cleared for a brand new flood storage centre.

According to one of the project partners, the new flood storage space will protect 250 homes in the local area.

While flood risk is not particularly high in the area, the new space will increase the capacity for water storage, which will eventually get released downstream.

The majority of the river works are expected to be completed within the week, after which the habitat regeneration works can begin.

Hogan told the LDRS how SERT now needs volunteers to help plant greenery around the flood storage space and along the river bank.

Hogan said: “The volunteering focuses on the more natural parts of the project, using wood in the river and planting. Anyone can come and do it.”

“If you’ve got a strong pair of arms you can come in and knock the posts in, if you’re a keen gardener you can put the plants in.

“It will be a chance to take part in the real naturalisation of it, to really make it beautiful and add the final touches to it.”

The project site, which used to be home to an old Jura spray factory, is now cleared of its industrial waste and replaced by stacks of local timber which the team will use to help the flow of the river.

Hogan told the LDRS: “It is now ready to be returned to nature and made beautiful again.”

Volunteers are encouraged to come along to the Wandle Fortnight events, coming up in September. 

More information about these can be found on the SERT and Wandle Valley Trust websites. 

The Wandle is one of the world’s purest chalk stream rivers and is home to many unique species. However, the Wandle also has particular historic significance. 

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.”

Councillor Christopher Woolmer, Lead Member for the Environment for Sutton Council told the LDRS: “We are proud to be one of the greenest London boroughs and our biodiversity team focuses on maintaining our green spaces and wildlife. Part of this work includes protecting and enhancing our rivers and wetlands across the borough.

“The Goat Bridge weir project is a long-standing piece of work to the River Wandle, which will allow fish and other species to move up and down the river more easily. Once restored, the river will be more resilient in the face of climate change.

"The project is led by Thames Water in partnership with the Council, the Environment Agency and the South East Rivers Trust.

“The project is progressing well and we encourage all interested residents to help out with planting and cleaning up the river, so the new stretch is in the best condition it can be, for wildlife and the people of Sutton to enjoy.”