On Monday 17 September, anglers fishing the River Wandle in South London noticed that the water was changing colour.  Shortly afterwards they saw dead fish floating to the surface.  They immediately reported the pollution to the Environment Agency whose staff were on the scene in 30 minutes taking water and fish samples.  At least 2,000 fish died on a 5km stretch of the Wandle.  The river had been recovering gradually over the past 10 years and is widely regarded as a beacon success story for an urban river.  The dead fish included barbel to 10lb, chub to 6lb, roach to 3lb and at least one dace over 1lb.
On Wednesday, after carrying out an urgent internal investigation, Thames Water contacted the Anglers’ Conservation Association to admit responsibility for the pollution.  They revealed that it was caused by a blunder at Beddington Sewage Treatment Works.  Sodium hydrochloride was being used to clean its tertiary treatment screens, but instead of being circulated back through the treatment works, it was accidentally discharged into the river.  The company immediately offered to meet with the local angling clubs and the Wandle Trust to discuss restocking and long term support for the work of the Trust.
Thames Water’s External Affairs and Sustainability Director Richard Aylard said “Everyone at Thames Water has been mortified by this whole incident.  As a keen angler myself, I was particularly upset to hear that we had caused such a setback to the recovery of this very special river.  We are determined to act quickly to work with the local community to put it right.”
The ACA’s Executive Director Mark Lloyd said “this is a disaster for the River Wandle which has become a vital part of the regeneration of this part of South London.  It has reversed years of work by the local community, the Environment Agency and Thames Water themselves.  However, both the prompt admission of responsibility by Thames Water and its promise to work constructively with the ACA, the Environment Agency, local angling clubs and the Wandle Trust to restore the river are extremely welcome.  This will save us wasting a lot of time fighting a legal case on behalf of our member clubs on the Wandle.  Once again, anglers were the first to notice and report the pollution and will lead the efforts to restore the river.”
Theo Pike, Director of the Wandle Trust, President of the Wandle Piscators and Vice Chairman of Morden Hall Park Angling Club said: “we have been working for years with the local community to restore this hidden gem of a river and we are very upset that this disastrous pollution has wound back the clock.  We look forward to discussing with Thames Water a sustainable long term plan for restoring the Wandle and ensuring that this event is not repeated in the future.”