Thames Water has been discharging untreated sewage into a chalk stream in Buckinghamshire, causing what campaigners say is untold harm to infant trout and habitats in the river.
The discharges into the River Chess in Chesham occurred days after the head of the environment agency told MPs that this should never happen, although he later qualified his remarks to allow for some exceptional circumstances.
Paul Jennings, chairman of the River Chess Association, said it had been notified of the sewage releases every day except one over the last week. Jennings is planning to erect signs along the river to alert the public to the discharges.
The signs read: “You are advised to avoid contact with the river water and suggest you keep pets and livestock out of the river.” The signs inform the public to contact the Environment Agency if they see dead wildlife on or around the river.
Chalk streams are a haven for species like the otter, kingfisher, salmon and trout. Jennings said the problem of excessive discharges into the river dated back to 2014, and the Environment Agency was aware of the issue.
Jennings said the sewage discharges were a result of four breaches in the system, of which Thames Water was aware. “The Environment Agency told Thames Water in 2014 and in 2020 to do something about this, that there was a problem here with groundwater ingress. But more than six years later, here we are in 2021 and it is still happening.”
A spokesperson for Thames Water said groundwater ingress was the problem. The company said it had set up CCTV to inspect the sewer pipes in the area and gather evidence of how the groundwater was getting into the sewage system. It planned to use the detail from the cameras, to get the funding required to reline the pipes.
“Our view is that discharges of untreated sewage are unacceptable, even when they are legally permitted, and we want to accelerate work to stop them being necessary,” the spokesperson said.
“We’re working hard in the Chess catchment to identify where groundwater is getting into the sewer network so we can reduce it, and we’re also funding a citizen science project to monitor the quality of the river.”
The company said it planned to upgrade Chesham sewage works, providing about a third more treatment capacity, with completion expected in 2023. “We absolutely share the River Chess Association’s vision for a cleaner, heathier River Chess and will continue working with them to achieve it.”
Giving evidence to the public accounts committee on 14 January, the Environment Agency chief Sir James Bevan indicated that there was no problem with sewage discharges into chalk streams, telling MPs that “we are not allowing people to discharge sewage into chalk streams.”
The Environment Agency said since Bevan had given evidence , he had written to the committee to clarify what he said.
“He was making the point that the Environment Agency does not permit companies to discharge untreated sewage into any chalk stream on a day-to-day basis,” the Environment Agency said.
“But – as with other watercourses – we do allow storm overflows to discharge exceptionally into chalk streams during rainfall to prevent sewers being overloaded and backing up into people’s homes.
“We also permit sewage treatment works to discharge treated sewage to chalk streams, but only within the strict permit limits required to protect the water quality of the receiving watercourse. These limits are set on a site-specific basis to protect the requirements of each chalk stream.”