Thames Water admits plans to protect River Wandle from sewage may not begin until 2035

By Harrison Galliven, Local Democracy Reporter

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. But residents fear the continued wastewater dumping threatens the river’s biodiversity.

Thames Water said they are still planning to begin work on the Beddington area on the boundary of Croydon and Sutton, but this could be as late as 2035.

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.

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.

Only 210 chalk streams can be found worldwide, with 85 per cent 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.

A Thames Water spokesman 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.

“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.”

Pictured top: The River Wandle flows past the Beddington treatment works (Picture: Wandle at Risk)