10-05-2025
The catastrophic extent of Britain's river problem: ‘Undrinkable, unswimmable, and now untouchable', says nature expert ROBERT MACFARLANE
As a child, Robert Macfarlane would spend long stretches of his summer holidays floating, face down, in the River Avon in Scotland. 'It ran along the edge of my grandparents' field in the northern Cairngorms. The water was cold and totally clear. I remember wearing a snorkel mask and seeing the shadows of salmon, these torpedo-like shadows, reorganising themselves in the water or just holding steady against the flow.'
Macfarlane, 48 and from Nottinghamshire, has written 12 books about the natural world. He has also scripted two documentaries (one about mountains, one about rivers, both narrated by actor Willem Dafoe); been nominated for the Wainwright Prize – the UK's top nature-writing award – four times and won once; and been described by The Wall Street Journal as 'the great nature writer, and nature poet, of this generation'.
We meet in Cambridge, where he lives with his wife and three children and is a professor at the University, to go for a two-hour walk along a chalk stream and discuss Is A River Alive?, his new book about waterbodies. Every so often our conversation stops for him to point out a wren building a nest on the edge of the stream, a collection of cowslips, or – most excitingly – a water vole. The latter has reflective eyes and a thick coat that dries as soon as it comes out of the water. 'That's the first water vole I've ever seen on this stream. That is amazing.'
Macfarlane started writing about rivers in 2020, travelling for research. In Canada, he spent 14 days kayaking along the 290km Mutehekau Shipu; in India, he found ponds that had been polluted with radioactive fly ash from nearby power stations. The ash settled on the water and turned its surface into a sort of jelly. Macfarlane saw children bouncing on it, as if it were a trampoline.
He hadn't realised, though, that in the four years it would take him to write the book, 'rivers would move so decisively to the centre of the conversation in the UK'.
The Oxford English Dictionary lists 13 different meanings for the word river; the BBC says a river is a large 'moving body of water' that flows across land into 'another body of water'. Macfarlane calls a river 'a gathering that seeks the sea'. Either way, there are around 1,500 in the UK. Of those in England and Wales, none is in 'good chemical health'.
Recently, Macfarlane saw a sign for the Kent, Hampshire and Sussex water operator, Southern Water, attached to some railings by a river. 'It read: 'Please try not to come into contact with the water. If you do, we recommend washing your hands thoroughly before preparing food.'' Above the text sat Southern Water's slogan: 'Water for life'.
There are lots more of these sorts of examples. Last year, three rowers from the University of Oxford contracted stomach bugs while training for the boat race, because the water from the Thames – which had splashed from their oars on to their skin – contained high levels of E. coli. This year, the charity River Action reported that the Thames still failed basic safety standards; water tests found E. coli levels were triple the Environment Agency's threshold for 'poor' bathing waters.
Meanwhile, Macfarlane, a patron of The Outdoor Swimming Society since 2006, says he would no longer swim in his local waterway, the River Cam. It is simply not clean. 'We live in a country where many of the rivers have become first undrinkable, then unswimmable, and now untouchable.'
The question, then, is how? And the first answer is sewage: 'the mega-villain of river death in this country'. Most of the UK's sewage network operates using a Victorian 'combined system', which means sewage and rainwater are collected in the same pipes, before travelling to treatment works. During heavy rainfall, these pipes can't hold all the sewage and the rain, so they overflow. Water companies are allowed to discharge untreated sewage into rivers in these exceptional circumstances, but they've also started dumping sewage illegally – when the rain is not that heavy, or even when the weather is dry. According to the Environment Agency, untreated sewage was discharged for a collective, and record-breaking, 3.62 million hours last year.
It is, says Macfarlane, a failure of the companies, which have underinvested in improving our creaky systems, 'sweated the assets they were handed', and meanwhile given enormous dividends to shareholders. (Between 1991 and March 2023, the 16 water monopolies in England paid out more than £78 billion in dividends and, despite being privatised with zero debt, they've borrowed more than £64 billion. Consequently, Thames Water, for instance, increased its 16 million customers' bills by 35 per cent this year.)
And it is a failure of the regulator, Ofwat, which has not enforced meaningful enough fines to discourage this sort of behaviour.
The other major problem for British rivers involves agricultural practises – particularly the disposal of slurry. This happens if farmers spread excess animal waste over their land; when it rains the waste runs into rivers. 'The government finding ways to financially reward farmers for better slurry management will reduce the amount of…' Macfarlane is about to say 'waste' – I think – but he sees a bird. 'Oh look, skylark!'
What is amazing, however, is how quickly rivers can heal. In 2024, the Klamath River in Oregon underwent the largest dam removal in US history. Within two weeks, salmon, which had not swum in the waters for a century, returned upstream. Or consider Switzerland.
In the 1960s, the country had some of the foulest rivers in Europe. After improvements to sewage infrastructure, they are now some of the cleanest. Damage is often reversible.
There's hope in the UK, too, according to Macfarlane. 'In the past three or four years, there's been an extraordinary rising up and organisation of communities. Charities like River Action, which is taking water companies to court, citizen science activist groups, swimmers, anglers, kayakers and everyday river lovers are driving change.' Macfarlane also mentions the River Rescue Kit, from River Action, which explains how to test your local waters for sewage; and online maps that report sewage dumps live. He rates the one on the website of Surfers Against Sewage.
But not all of our waters are dirty. Thanks to 'coalitions of the loving' and 'some landowners who have pursued very enlightened policies', rivers including the Nar in Norfolk remain clean. Scotland – and specifically the Highlands – has generally better water quality than England, too. The Avon, where Macfarlane floated as a child, would still look clear, he says. (In general, Macfarlane's wild-swimming rules are as follows: don't swim after heavy rain; try not to swallow water unnecessarily; cover up cuts; and check the maps. 'There's still lots of happy, healthy fun to be had.')
There is also 'daylighting' – the process of restoring rivers that have been otherwise buried. This February, a stretch of Sheffield's River Sheaf was uncovered. Before then, it had been underground for 100 years.
The main theory of Macfarlane's book is that rivers are alive, not just alive in the sense of being an ecosystem, a place where other animals and plants live, but alive themselves: their own vast, complex, living entities.
I was not entirely sure, to be honest, that I understood it as an idea. But, looking at the photographs of the Sheaf seeing daylight for the first time in a century, it becomes clear that the river is, absolutely, alive.
Last month, Macfarlane travelled to the Highlands for a holiday. He swam in rivers, watching 'your skin turning that sort of amazing, coppery bronze'. What did it feel like to be in clean water? 'Certain powers in this country have made the mistake of coming to regard rivers entirely as resources, not as life forces. But in a river, you feel life flowing into you. It feels like enlivenment.'
Is A River Alive? by Robert Macfarlane (Hamish Hamilton, £25) is available now. To order a copy for £21.25 until 25 May, go to or call 020 3176 2937. Free UK delivery on orders over £25.
200,000km
collective length of rivers in the UK
14%
rivers in England and Wales in 'good overall health'
3.62 million
collective hours that sewage was discharged into British rivers in 2024
354km
length of the Severn, Britain's longest river
200 tonnes
amount of plastic removed from the Thames each year
1,500
rivers in the UK
20
rivers buried under London's streets
2 years
time that water company bosses can now spend in prison for illegal sewage spills
