Following August’s serious pollution incident, the Wandle was hit by an even greater catastrophe on Monday 17 September, when a large quantity of sodium hypochlorite cleaning solution was released from Beddington sewage treatment works into the Mill Green area of the river.

Local Environment Agency officers were on the scene within minutes, but at least 2000 further fish were instantly killed over a 5km reach, and longer-term impact on water weeds and invertebrate life in the river has been much more severe. 

Thames Water has pledged to work with all local groups to repair the damage, and has issued the following statement:

River Wandle pollution

Thames Water has pledged to carry out a thorough clean-up of the river Wandle after chemicals leaked from a sewage treatment works.

A significant number of fish are believed to have perished after cleaning solvents entered the river during work being carried out to improve the water quality in the Wandle in South West London.

Director of Wastewater Services, Bob Collington apologised on behalf of Thames Water and said it would do as much as possible to bring the river back to full health.

“We want to apologise to everyone in the community who enjoys the Wandle.  

We are dismayed this has happened, particularly after all the investment we have made in recent years in bringing the river back to health and turning it into a haven for wildlife, as well as the work we have carried out in preventing incidents such as this one.

A thorough investigation is being conducted and we are taking immediate steps to ensure this sort of event cannot happen again.

Our top priority now is to work closely with the Environment Agency on cleaning up the affected areas of the river, and we will do everything we can to restore the river’s ecosystem, including replacing lost fish and affected habitats.”

In the next few weeks the Wandle Trust, the Wandle Piscators, the Environment Agency, and the Anglers’ Conservation Association will be consulting closely with Thames Water, putting all the necessary safeguards in place to ensure that our unceasing work on the Wandle can never be compromised in this way again. 

Our monthly community cleanups and annual Trout in the Classroom programme will continue, and we remain more committed than ever to restoring the Wandle to full health and biodiversity as the very best sustainable urban showcase chalkstream in the world. new top level domains .