Work to protect London river from sewage may not happen until 2035 as Thames Water says it’s not a priority

Thames Water has admitted that works to protect the River Wandle from sewage may not take place until 2035. This comes following the official apology from water companies in May, when they admitted to not acting quickly enough on sewage spills and vowing to “put things right”.

The Wandle finds its source in the foothills of the North Downs before flowing nine miles downhill through Sutton, Croydon and Wandsworth before emptying into the Thames. The river is one of London’s only chalk streams where anglers can often find brown trout, chub, barbel and roach. However, residents fear the continued wastewater dumping threatens the river’s biodiversity.

News of the river’s future came to light during a recent scrutiny committee held by Sutton Council, in which councillors questioned representatives from Thames Water, the body responsible for most of London’s water supply and wastewater treatment. In the meeting, Thames Water told councillor Bobby Dean they are still planning to begin work on the Beddington area but this could be as late as 2035.

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Polluted water meeting a clean chalk stream
A number of stormwater discharges stem from the nearby Beddington treatment works
(Image: Wandle: River at Risk)

Thames Water claimed it is currently carrying out an ecological assessment to determine the priorities for new works. If the Wandle is deemed a priority, works could be brought forward to 2027. Thames Water also admitted that, beyond work on the Thames Tideway tunnel, no local work has been carried out on the Wandle in the last five years. While the £4.5bn tunnel will help to reduce sewage dumping near the mouth of the Wandle, the southern end of the river will not be impacted.

Thames Water was also pressed on its 25-year plan that will commit £611m of investment in the Beddington area. Despite the apology given by the water industry in May, discharges have continued. According to the South East Rivers Trust, there were 13 separate incidents between December 5, 2022, and December 5, 2023, leading to over 25 hours of discharge. These figures omit the most recent discharge on December 8, which was investigated over heightened levels of ammonium. However no issues were found with the sewage treatment system at Beddington, so it’s believed the ammonium came from a fly-tip in the river. The chemical is often used in fridges as a gas to help keep food cool.

Councillor Dean asked if they would commit any more money to the project and bring the time-scale forward, considering the apology. In response, Thames Water stated the cost of overcoming regulatory restrictions in sourcing engineers would make such a move unviable.

River Wandle in Carshalton
Thousands of people visit the Wandle trail each year
(Image: Nigel Cox)

Unsurprisingly, this revelation has raised concerns from South London locals, who feel a strong connection to the river. This consensus, which includes Sutton’s Liberal Democrats, anglers and residents, expressed their concerns in a short documentary which recently premiered in front of a full house at Carshalton’s Cryer Arts Centre. The event was attended by several conservation groups who regularly clear waste from the river and monitor its health.

‘Wandle: River at Risk’ charted the river’s history and significance as a rare chalk stream, as well as highlighting the very real dangers it faces from pollution. Only 210 chalk streams can be found worldwide, with 85% of them in England. The Wandle is a rare example of a British chalk stream, and its titular Wandle trail attracts visitors from far and wide.

The river also has great historic significance. Over the years, the Wandle has powered Roman mills and William Morris’ famous textile factory at Merton Abbey. Wandle historian John Hawks said the Wandle was once known as the hardest working river for its size in the world.

Fly tipping in the Wandle
Parts of the Wandle are often blighted by commercial fly-tipping
(Image: Wandle: River at Risk)

Dean, who is campaigning to be Carshalton & Wallington’s next Liberal Democrat MP, said: “I live right by the Wandle. I walk my dog by it every day. Making this film, I’ve discovered its history and just how important it is to everyone’s daily lives here.”

He added: “It’s incredibly special – one of the few urban chalk streams in the world. So much effort has been put in over the years to restore the river, after its post-industrial decline. But sewage dumping and other pollutants are putting it under threat once again.

“The Government must get its act together and hold the water companies to account for their failure to protect our local river. It really feels like a community movement to stand up for the Wandle is building – and it makes me feel hopeful that we can get the river back to its best.”

Wandle in Wandsworth
The Wandle finally joins the Thames downstream in Wandsworth
(Image: Stephen Craven)

A Thames Water spokesperson said: “The Environment Agency’s rating of the River Wandle clearly states it was not downgraded last year. The performance of our Beddington sewage treatment works (STW) is good, and it is therefore not one of the 250 STWs and sewers that we will be upgrading in the next few years.

“Taking action to improve the health of rivers is a key focus for us, and we’re working with our partners to help improve the River Wandle, which is an urban river affected by multiple pollution issues. We’re aware of the problems caused by misconnections on the Wandle, which are mostly wrongly connected pipes on private properties. We have a programme of work to help rectify this, and last year we partnered with the South East Rivers Trust and local volunteers to identify misconnections in the area. Since 2020 we have identified 105 misconnections.

“We regard all discharges as unacceptable, and we have published plans to upgrade over 250 of our sewage treatment works and sewers. The Thames Tideway Tunnel, a £4 billion investment, is nearing completion. This project, combined with previous upgrades we’ve made to our London sewage works and the building of the Lee Tunnel will capture 95% of the volume of untreated sewage currently entering the tidal Thames in a typical year.”

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