Thames Water dumped untreated effluent for more than 68,000 hours into river systems around Oxford last year, campaigners have revealed, arguing that the amount of money the company plans to spend to improve the situation is woefully insufficient.
The company discharged raw sewage into the River Thames and its tributaries including the Rivers Windrush, Thame, Evenlode and Ock 5,028 times in 2021, according to data analyzed by the Oxford Rivers Improvement Campaign (ORIC).
Using data from Thames Water and applying the Environment Agency’s formula for the capacity required at any treatment plant, campaigners have estimated that the 10 major treatment plants operating in the Thames area upper – from Didcot in the south to Moreton-in-Marsh and Bourton-on-the-Water in the Cotswolds – have not been able to handle the full capacity of sewage for the population of 1.1 million .
Their calculations indicate that the Oxford and Witney treatment plants can only cover 62% of the capacity needed by the population, and that the Banbury treatment plants can only cover 49% of the capacity required.
Failure to invest in the capacity of sewage treatment plants has led to more raw sewage flowing into rivers, campaigners said. The 10 factories discharged wastewater into rivers in 2021 for an average of 11 hours per week. Wastewater treatment plants in Oxford discharged raw sewage into the waters for 892 hours in 2021, Swindon for 501 hours and Witney for 935 hours.
According to ORIC, Thames Water is investing in upgrading four of the major sewage treatment plants and 11 smaller ones, only a third of the works that need to be expanded to stop sewage discharges into the rivers. When the increase in population is taken into account, the investment plans cover only a quarter – 15 out of 57 – of the treatment works requiring investment by 2025.
“The simple truth is that Thames Water’s plans are completely inadequate,” said Mark Hull, former water industry consultant and founding member of ORIC. “Given the well-established and long-standing problems in the Upper Thames region, it is outrageous that proper and co-ordinated investment plans for the whole region are not in place.
“Thames Water and the Government Environment Agency failed to address this issue for many years. Their continued underperformance is beyond comprehension, especially as the sector’s financial regulator, Ofwat, has made it clear that it will not oppose the necessary investment.
The report, released by ORIC on Wednesday, found that even where Thames Water had planned investment, capacity expansion may be insufficient for the 2020s and 2030s. At Witney processing works, investment will increase capacity by 50% but that would improve works to just 93% of the required capacity based on 2020 population, the report said.
On the upper Thames, 102 treatment plants discharged into the rivers in 2021. Forty-nine of these discharged more than 10 hours per week; and almost a quarter of jobs discharged for more than 1,000 hours in the year.
The campaign group analyzed the extent of raw sewage discharge into the upper Thames from Environment Agency data for 2021. It also looked at the agency’s investment database water companies.
Hull said: ‘The government, the Environment Agency and Thames Water continue to tell us they are addressing the issues. The truth is simple. They are not.”
A spokesman for Thames Water said it was reviewing the ORIC report: “Our focus will always be on trying to do the right thing for our rivers and for the communities who love and appreciate them. We consider all discharges of untreated sewage to be unacceptable and will work with the government, Ofwat and the Environment Agency to speed up work so it is no longer needed and we are committed to transparency.
“We recently launched our River Health Commitments, which include a 50% reduction in the total annual duration of discharges across London and the Thames Valley by 2030, and within this an 80% reduction % of sensitive watersheds. We have a long way to go – and we certainly can’t do it alone – but the ambition is clear.