Polly Penn, Head of Working with Communities at the South East Rivers Trust (SERT), explains who they are and what they do, with a focus on the river Wandle, a London chalkstream much enjoyed by Farlows staff.
WHO ARE THE SOUTH EAST RIVERS TRUST?
The South East Rivers Trust (SERT) is the river restoration charity for South East England. Our vision is that rivers across the South East are clean, healthy & rich in biodiversity. This is because we believe that when rivers thrive, so do people and nature. While the Trust now looks after 12 river catchments from Basingstoke to Dover, our story began in the 1990s on a small chalk stream in South London - the River Wandle.
The story of SERT and the River Wandle are forever entwined and are a great example of what dedication, perseverance and partnership working can achieve for a river.
THE WONDERFUL WANDLE
The Wandle is the largest chalk stream in south London, rising from chalk aquifers along the North Downs and flowing through four London boroughs before joining the Thames in Wandsworth.
The Wandle was the engine room of nineteenth century London, powering more mills along its banks than any river of its size in the world. Once a thriving trout fishery, by the 1930s, pollution had decimated the fish population. By the 1960s, the river was essentially an open sewer, declared biologically dead.
As time has gone on, industry has declined and water treatment legislation has improved water quality, but the Wandle was still left with a legacy of historical use and abuse.
PEOPLE POWER
In the mid-1990s, a group of concerned residents and anglers banded together for the Wandle. Tired of seeing the state of the precious chalk stream, they took their own action to bring the river back to life. Community cleanups became a monthly task – removing fly-tipping and rubbish from the river while donning chest waders and encouraging local people to get stuck in. Motorbikes, mattresses, tyres, carpets, furniture and more were found and removed from the river, freeing the river bed from years of neglect.
These events only grew in popularity attracting huge numbers of volunteers each month, helping improve the river but also raising its profile whilst showing how much the river means to the local community and fly fishing anglers. With such support, the group became an official charity to protect the river – The Wandle Trust.
TROUT IN THE CLASSROOM
The Wandle was once famous for its brown trout – a precious chalk stream species. By the 1930s the species had died out and while since then water quality had improved, the iconic fish had not returned.
In the 2000s, we started introducing brown trout back to the Wandle. We did this by working with local schools through our Trout in the Classroom programme. Schools were set up with the equipment and knowledge to hatch trout eggs and raise the fry until they were ready to be released into the river. The programme ran for 10 years, engaging 35,000 children and releasing around 8000 trout fry.
We started to notice that the trout survived better than expected, which gave hope for the further restoration of the river. If we can improve the habitat and further improve the water quality, could the trout become a self-sustaining population?
BRINGING THE WANDLE BACK TO LIFE
We focused our restoration efforts on the Carshalton Arm of the Wandle. Initially, the river was overwide, straight, fragmented by weirs, impounded, and heavily polluted. Our goal was to restore the river's natural ecosystem, making it a resilient community asset with a self-sustaining trout population.
We addressed fish passage by reconnecting the river and lowering or notching five weirs, which restored natural flow and reconnected 2.5 km of the river. Habitat restoration involved narrowing and meandering the river using bioengineering techniques, adding 370 tonnes of gravel, and planting over 3,000 native plants. These efforts improved flow, created diverse habitats, and removed invasive species.
A hidden killer for many rivers is road runoff - a cocktail of toxic chemicals washed into rivers from our roads. The Carshalton Arm of the Wandle received runoff from the surrounding roads through 3 main surface water outfalls so that after rain, all the oils and heavy metals on the roads drains straight into the river. With no space to install cleansing wetlands, we fitted 3 Hydrodynamic Vortex Chambers - silt traps - onto the surface water drains, underneath the roads.
We trialled a range of innovative water quality enhancement techniques around the catchment. We added Siltex to the ponds at the source of the Wandle to help break down the organic silt from all the ducks and bread. We installed smart sponges in gully pots down drains to help mop up the oils running down the roads. We trialled Mycobags growing mushrooms to help take up sediment and heavy metals and we developed a volunteer pollution monitoring scheme to help the Environment Agency assess pollution incidents.
The final outcome of all of this work was a thriving river with brown trout beginning to reproduce successfully for the first time in over 80 years! The Carshalton Arm also attained Good Ecological Potential, a hard target under the Water Framework Directive.
PARTNERSHIP POWER
Throughout it all, we couldn’t have achieved this impact without the help of partners. Building partnerships is central to how SERT works. Without partnership working, it would be impossible to achieve our vision that rivers across the South East are clean, healthy & rich in biodiversity.
The Wild Trout Trust helped us with our first restoration project, upskilling our staff. The Environment Agency supported our work. Local residents put up with road closures and parking restrictions, stored our diggers, watered the plants and took an interest in all we were doing.
The local water companies (SES Water and Thames Water) supported our work to tackle road runoff. Sutton Council paid to connect several unmapped pipes for us, and Conways took on emptying the silt traps to ensure they remain effective. We also benefited from five universities and six MSc students who helped monitor these techniques and the impacts of road run-off.
A LASTING CHARITY LEGACY
Without our success on the River Wandle as the Wandle Trust, we would never have become the charity we are today. It was our experience and expertise that resulted in our growth to become the South East Rivers Trust and bring impact to rivers across the South East.
To find out more about SERT and how you can help, please visit: southeastriverstrust.org
