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Henley Rowers and Local Community Expose Sewage Pollution in the River Thames

River Action and residents of Henley-on-Thames have released findings of one of the most intensive citizen science programmes to have been conducted in the UK, testing the River Thames at Henley for levels of phosphate, nitrate and harmful bacteria. Testing was undertaken every weekday over a four-week period by River Action and local residents. The reveal that the stretch of river used for the world famous Henley Royal Regatta, known as the ‘Henley Mile’, is being severely impacted by sewage pollution.

Testing undertaken both upstream and downstream of Henley Sewage Treatment Works (STW) showed levels of E-coli and intestinal enterococci spiked significantly after a rainfall event on 20th June, with levels increasing fourfold, equivalent to an official bathing water status of ‘poor’. This means the water posed a serious risk to human health during these times.

Levels of phosphate and nitrate along the Henley Mile throughout the four weeks were consistently double the levels considered ecologically damaging for rivers, indicating that the River Thames at Henley is excessively nutrient enriched and in a very poor condition. Overall, the results show the River Thames at Henley is in poor ecological health and can also represent a health risk to river users. The testing demonstrates that the Henley mile is severely blighted by sewage pollution.

Analysis undertaken by Windrush Against Sewage Pollution (WASP) suggests that Henley STW appears to be breaching permitted levels of ammonia discharged straight into the river. WASP’s analysis also suggests that there have been illegal discharges from the treatment works almost every year between 2009 and 2019. In 2022, Thames Water reported to the Environment Agency that no sewage discharges had occurred from Henley STW, but WASP analysis shows that there is evidence of at least four discharges occurring that year.

The stretch of the River Thames running through Henley is home to international rowing and swimming events and is a popular spot for visitors and locals for rowing, swimming and playing. The results are revealed just weeks after reports of a group of teenage boys becoming violently ill after swimming in the river, and just days after the world-renown Henley Royal Regatta which saw hundreds of rowers, including top international athletes, take to the water over the week-long event.

Sir Steve Redgrave, Chairman of Henley Royal Regatta said:

“At Henley Royal Regatta, we are deeply concerned about the impact that sewage pollution is having on our beautiful river. Sewage pollution is harming the environment that we enjoy and respect so much.

“I canoe from my home town of Marlow at Longridge. There’s a water treatment plant there and sometimes you can see from the colour of the water that there has been a discharge – it’s not somewhere I would ever want to fall in. We have to improve this situation so that we can preserve wildlife and make our rivers safe for everyone who uses them. That’s why I, and Henley Royal Regatta, are backing River Actions’ Charter for Rivers and throwing all our weight behind the campaign to end sewage pollution in the River Thames at Henley.”

The findings have caused outrage amongst the local population and the rowing community who are deeply concerned that the recent departure of Thames Water CEO Sarah Bentley and news of the company’s weakened financial position will result in increases in pollution. They are urging Thames Water to take immediate action to stop breaking the law and engage responsibly with the community, undertake more regular and transparent testing of water at Henley, invest in the Henley Sewage Treatment Works and install a number of mitigations, including UV treatment. They strongly urge the Government and Thames Water not to neglect their collective responsibility for addressing the sewage pollution crisis and the freshwater emergency.

River Action and the Henley community are calling on the Government and all political parties to adopt the Charter for Rivers as a matter of urgency. The Charter – which was presented to political decision-makers at a reception in Westminster on 3rd July –  is supported by over 70 cross-sector organisations and was recently endorsed by Sir Steve Redgrave. It sets out the actions that need to be taken to rescue Britain’s rivers for people and nature.

James Wallace, CEO of River Action said:

“The results of this citizen science prove the dire state of England’s capital river. Wildlife along the Thames is collapsing and river users are at serious risk. The Government and industry are treating our national life support system like a diseased open sewer while staring down the barrel of a freshwater emergency.

“However, it’s time to end the culture of blame and denial. Unravelling the financial mess left by rampant profiteering and deregulation must not distract us from rescuing our rivers together. Thames Water and the Government must admit culpability and invest in modernising infrastructure and enforcing the law, targeting exposed communities like Henley.

“The Charter for Rivers positions healthy rivers as a top priority in the next general election to all candidates and voters, clearly laying out urgent actions to end pollution and over abstraction. We have seen what can be done in a national health or energy crisis. Government ministers and corporate CEOs must publicly commit the finances and solutions this emergency requires, or endure the wrath of the electorate.”

Joanna Robb from the Henley Mermaids said:

“We know the Thames intimately – we swim in it year round, in winter and summer and have swum its length from Castle Eaton to Marlow. But over the past five years we have been horrified by the scandal of sewage dumping into our precious river and its tributaries, caused by the water industry’s lack of investment in sewage infrastructure.

“We have witnessed the impacts of sewage pollution with our own eyes: sanitary products, sewage foam, sewage tide lines on swans and dead fish. We are contacted regularly by parents asking us if the river is clean enough for their children to swim in. It disgusts us that in one of the world’s richest countries in 2023, our children can’t even swim in our rivers without falling ill.

“In the water-stressed South-East of England, we are also facing a crisis of water security. With accelerating climate breakdown, it’s vital we have a water industry that can deliver water to our population while protecting our rivers.

“This crisis can be fixed. We can have clean, healthy rivers safe for humans and nature. We need real investment in our crumbling sewage and water infrastructure and meaningful, positive action to rescue our rivers. We need a water industry that puts people and nature at its heart. We wholeheartedly support the Charter for Rivers.






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