An enthusiastic and close-knit community of bore riders has built up around the phenomenon, riding the 250 or so waves each year, especially so-called five-star bores – predicted waves caused when tidal differences in the estuary are at their largest. For Rogers, the Severn bore is a wonder of the world and riding it is a journey. “I’ve surfed 5 miles through landscapes. It’s like a mini adventure,” he says.

But Britain’s rivers are being flooded with plastic waste, manure, runoff and raw sewage, and none more so than the Severn. “Our rivers are abused. We use them as gutters,” says Rogers. “A lot of my friends get what we call river belly, which isn’t very nice, as you can imagine. And I’ve had stomach bugs and I’ve got Weil’s disease before.” Now Rogers and other bore surfers are campaigning to improve the water quality of the Severn and other rivers around the UK, taking part in clean-ups and asking river users to demand better from water companies and politicians.

In the past ten years, Soraya and her community have seen the river deteriorate. The water has turned opaque, coated with algae, its fish populations quietly diminishing. That’s why she feels compelled to monitor the wastewater coming from the nearby treatment works that she says are severely damaging the Windrush river, and encourages others to join her.

Created for, and by �鶹��ý’s sister publication the i paper, as part of our ongoing #savebritainsrivers campaign.

When Barrow started diving into Britain’s rivers in 1989, the experience blew his mind. The underwater environment was brimming with grayling, barbel and many other species of fish. Now, 30 years on, his experience of swimming in Britain’s rivers has drastically changed. He regularly emerges from the river covered in human waste and sanitary products, he says.

This film was created for and originally published by �鶹��ý‘s sister publication the as part of our ongoing #savebritainsrivers campaign.

The UK project, led by ZSL conservation biologist Thea Cox, sees dwarf eelgrass (Zostera noltii) planted in research beds across three intertidal sites using two techniques. One involves the transplantation of fully grown plants to new areas, where the plant can spread via rhizomes, and another involves the harvesting and planting of seeds from nearby donor meadows.

The team is monitoring each research bed to better understand the effects that sediment type, temperature, light, current and wave energies have on the plants. The eventual aim will be to scale up the restoration. “What’s so important about [seagrass] is the way it creates a habitat,” says Cox. “Hopefully we’ll see higher numbers of fish, a greater diversity of fish, seahorses, sharks being able to use that habitat and come back in greater numbers to clearer, cleaner waters,” she adds.

When most people are asked to name a river, they often reach for the most famous: the Amazon, Nile, Ganges, Mississippi, Thames. But these aren’t the only remarkable rivers out there. From a river that experiences a thundering wall of water that hurtles upstream to an underground river that is home to bird-catching spiders, here are 10 more from around the world – and solar system.

The Itchen, England

A kingfisher dives between the white flowers of common water-crowfoot as clouds of mayflies hover overhead and an endangered white-clawed crayfish forages on the gravel riverbed. Salmon and trout head upstream, avoiding the otters scrambling amongst the yellow irises.

This is the river Itchen, a chalk stream that flows for 40 kilometres through Hampshire in southern England. It is “a globally important river”, says Martin de Retuerto at the . The variety of life and abundance here “truly is quite astounding”, he says.

Chalk streams are globally rare habitats. . The water comes from the chalk aquifers below, making it mineral-rich, clear and a stable temperature throughout the year. Plant growth is encouraged by the large amounts of light that can penetrate this clear water, alongside the high availability of minerals, especially calcium. “With a chalk river, the type and quality of water gives rise to very complex and diverse plant communities that are up there in a global context,” says de Retuerto.

Like all rivers in the UK, the Itchen has been modified by humans. Recent restoration work has focused on rejoining the river to its flood plain, opening passages for salmon to travel upstream and reintroducing lost species, such as the Eurasian otter. One success story is the . “They nearly went extinct in the early nineties when the crayfish plague from North American signal crayfish got in the river,” says de Retuerto.

The biggest threats to the Itchen are abstraction of water from the aquifer and , says de Retuerto. “We’re not treating [the Itchen] like the finely tuned, high-performance thing that it is.”

The Diamantina, Australia

Winding through arid west and , has . Large sections are dry for months at a time until water floods downstream following summer monsoon rains in its upper sections. “It’s really spectacular,” says at Flinders University in Adelaide. “It’s this gushing torrent of water that wakes up the outback.”

As the water travels downstream, it bursts out of its main channel and fills hundreds of intertwined channels. In the wettest years, this . Only , on average, does enough rain fall for the water to reach all the way to its terminus: Kati Thanda-Lake Eyre in South Australia.

Birds quickly arrive at the flowing river to feed and breed, including . “It’s beautiful being out in the centre of Australia when it’s rained,” says Shanafield. “It’s just amazing to see all the wildlife that comes out.”

The plants and animals living in the area are adapted to this “boom and bust” cycle, such as . “These ecosystems can wait years if they need to and then, as soon as it rains, they come to life,” says Shanafield. “[They] then disappear again and wait until there’s water in the stream.” During dry periods, provide .

Around 70 per cent of Australia’s rivers only flow for some of the time. “What’s interesting to me is that, if you look at a map of Australia, it looks like there’s no rivers here, or just the Murray-Darling river snaking down the east coast,” says Shanafield. “Actually, there’s rivers all over the place.”

The Qiantang, China

For a spectacular natural phenomenon, look no further than the Qiantang river in China’s Zhejiang province, which is home to the . “It is an almost vertical wall of water rushing upstream along the river with its foaming front and thundering noise,” says Dong-Zi Pan at the Zhejiang Institute of Hydraulics and Estuary, who has for 15 years.

The bore forms as an incoming tide is funnelled into the narrow entry to the Qiantang from the wider Hangzhou Bay and passes over a sand bar at the river’s mouth that reduces the water’s depth. Together, these concentrate the water into a wave that sweeps upstream at between 4 and 7 metres per second. Normally, the bore is about 1 to 2 metres in height, says Pan, but it – and it can get even larger if it hits an obstacle. “It’s different every time and makes me feel exhilarated,” he says.

The largest bore of the year is seen in August, when the sun, moon and Earth are in their closest alignment – creating the largest incoming tide – and the prevailing winds are in the right direction, says Pan. The bore can travel up to 100 kilometres upriver and hundreds of thousands of people line the banks when the largest bores are predicted to appear.

Caño Cristales, Colombia

This beautiful river is the Caño Cristales in Colombia. It is a riot of colour between June and November: reds, greens, blues, yellows and purples all glisten under the crystalline water.

These colours are partly due to the plant , also known as Macarenia clavigera. Found only in this region of Colombia, it has green hues in shady regions and red ones in sunny spots. “The other colours of Caño Cristales are given by its surroundings: the sky, the sand, the stone,” says at Cormacarena, a local government department with responsibility for the river.

To survive the dry season, the plant nestles between the stones in order to get moisture from the humidity trapped there, says Leyva Quijano. Once rain refills the river, the plant is “reborn”, she says. This rainwater flowing off the land is also responsible for the circular pits seen in the riverbed. Over millions of years, sand and small stones carried into the river have been whirled around in eddies at the same spots, carving out the pits, says Leyva Quijano. This creates different depths of water, adding to the range of colours.

The river is increasingly popular with tourists, and one challenge is to prevent damage, says Leyva Quijano. Climate change is also having an effect. “The rainy and dry seasons are changing, which affects whether the plant has developed,” she says. “If it has not reached an appropriate height, it can be uprooted by the force of the waters [following rain].”

The Elwha, Washington state

In 2014, something remarkable happened to the Elwha river in Washington state: it could flow from source to sea unimpeded once more. Two hydroelectric dams built in the early 1900s had been removed in .

The dams had made a huge impact on the river. Built without passages for fish to pass through, , including salmon central to the . They also flooded cultural sites and disrupted sediment flow, which caused to deteriorate. Fish populations crashed.

The , alongside environmental groups, . In 1992, the US Congress passed the , with work beginning on deconstruction in 2011.

It took just .

As the dams were breached, decades’ worth of sediment trapped behind them was released, with , which grew by 60 hectares in five years. This sediment pulse was , although they are expected to bounce back as the Elwha returns to its natural state.

The Vjosa, Albania

Known as the last wild river in Europe, the Vjosa is free flowing for almost its entire 270-kilometre length, with only the first 10 kilometres at its source altered by humans. “That is very, very rare in Europe, especially in central Europe close to the global tourist hotspot, the Mediterranean Sea,” says at environmental group RiverWatch.

Rising in the Pindus mountains in Greece, passes through narrow gorges and canyons into a wide, braided floodplain filled with sandbanks, willows and poplar trees, before meandering towards its estuary and entering the Adriatic Sea.

This , alongside the clear, clean water, means it is home to , including . “For wildlife it is important, because it is one of the last intact rivers at all in Europe,” says Eichelmann. “Lots of species, especially insects, have their last ‘home’ in the Vjosa.” Some of the rarest are the and the .

Plans to build 40 dams along the Vjosa and its tributaries sparked in Albania. “It is only now that locals and Albanians became aware how unique their river is,” says Eichelmann. On 15 March, the river was designated Europe’s first wild river national park, which should protect the river and its tributaries within Albania.

Puerto-Princesa underground river, the Philippines

Flowing through lush rainforest and past pinnacles of limestone rock, you would be forgiven for thinking the Cabayugan river on the island of Palawan in the Philippines is just another tropical river – until it abruptly disappears into the rock to spend its final 8 kilometres underground.

Here, it becomes the Puerto-Princesa underground river and flows through a series of spectacular caverns until it. It is home to an “extraordinary biodiversity for an underground river”, says Paulo Agnelli, who explored the caves as part of an expedition by La Venta, an organisation that explores hard-to-reach geographical features. “We found 17 species of vertebrates and at least 84 species of invertebrates.”

roost above the river, “which animate the tunnels along the river at dawn and dusk [as they] go out in search of insects”, he says. These are , while their guano supports ecosystems both in the caves and within the river. Also seen are freshwater and marine fish, molluscs, shrimp, scorpions and “huge and beautiful spiders” that can catch bats and swiftlets, says Agnelli.

“The co-existence of as many as five different ecosystems in a single cave is absolutely uncommon, if not unique,” says Antonio De Vivo, also part of La Venta. The river has the longest known underground estuary, with seawater reaching up to 5 kilometres upstream during the dry season. The contrast between the seawater and the colder freshwater “leads to the development of very rare phenomena, such as the formation of true clouds inside the huge chambers of the cave, even with short ‘rainstorms’”, he says.

Whanganui river, New Zealand

Found on New Zealand’s North Island, the Whanganui river rises on the slopes of the active volcano Mount Tongariro before flowing downstream for 290 kilometres to the Tasman Sea. It was the first river in the world to be granted legal personhood, following the longest legal battle in New Zealand’s history, .

The river is spiritually important to the Whanganui Iwi, who recognise it as their ancestor and who, for 150 years, from threats such as the removal of gravel, destruction of eel weirs and proposed hydroelectric dams. In response, government legislation and tribunals were used to cut away those rights and ownership of sections, such as the riverbed, was vested to the Crown.

As part of settling these disputes, the was passed in 2017 by New Zealand’s parliament, giving the river the same rights and responsibilities as a person. It includes – a representative from the government and from the Whanganui Iwi – to defend the river’s legal rights and maintain its health. , including improving spawning grounds for fish and habitats for the declining freshwater mussel.

Unnamed river, Antarctica

Antarctica may be a world of ice, but there is liquid water there if you know where to look. flowing into the Weddell Sea. “Now we know they exist, there will be others discovered,” says at Imperial College London, who was part of the team that found the river.

. However, it turns out enough heat is generated from the friction created as an ice sheet moves over rock, as well as heat from Earth itself, to melt its underside. “This river is special because it’s not surface melting that causes it, but basal melting – completely beneath the ice,” says Siegert.

This under-ice river helps lubricate the ice sheet as it flows towards the sea, allowing it to move more quickly than it would otherwise, says Siegert. This process could be affected as the world warms because of climate change. “As the ice sheet does change due to fossil fuel burning, so, too, will the flow of these rivers,” he says.

Vid Flumina, Titan

Earth isn’t alone in having rivers. Mars once had rivers larger than Earth’s, although all that is left of them now is dried-up valleys. But there is: Saturn’s icy moon Titan. The 400-kilometre-long Vid Flumina in Titan’s north polar region was spotted by the Cassini probe in 2012. This remarkably straight river is and flows into a sea called Ligeia Mare.

Analysis of the radar data sent back by Cassini suggests it . But, at -179˚C, Titan is too cold for liquid water. Instead, .

“We think it’s raining in the highlands and flowing down into these river valleys,” Thomas Farr, then at NASA’s Jet Propulsion Laboratory in Pasadena, California, told �鶹��ý at the time of Vid Flumina’s discovery.

UK government inspections designed to prevent the illegal extraction of water from natural sources in England have almost halved since their peak in 2015/2016, �鶹��ý can reveal, in part due to a shift to “office-based” checks because of the coronavirus pandemic.

Water firms use natural sources such as rivers and ground water to supply the general public, while farmers and other businesses such as golf clubs can also extract water directly for irrigation. This use of water, also known as abstraction, can harm the environment, for instance by putting fish at risk by reducing river flow, says at Wildfish, an environmental charity.

Because of this, any business in England that extracts more than from a water body requires a licence from the Environment Agency (EA). The latest available figures suggest that there are over in England as of 2018.

Despite licensing, around , according to the EA.

Tackling this requires a rigorous inspection system, says Overington. But a freedom of information request by �鶹��ý has revealed that the current inspection regime is anything but rigorous.

According to figures for the past decade released by the EA, the number of onsite abstraction inspections it conducts has fallen from a high of 4904 in the 2015/2016 financial year to less than half that in 2022/2023, with just 2303 inspections.

Licence holders are required to report the amount of water they take from a source, with onsite inspections verifying those figures. A worker at the EA, who wishes to remain anonymous, says the cutbacks in onsite inspections pose a significant risk to England’s water bodies.

“Due to a reduction in resources and a shift in priorities, the EA has significantly scaled back its inspection programme of water abstractions,” they say. “This has the potential for companies to exceed their licensed quantities without proper scrutiny.

“That’s why onsite inspections are so crucial. This behaviour is often going unpunished and can cause significant damage to our precious water habitats.”

The coronavirus pandemic and resulting lockdowns are partly responsible for the fall in inspections, with just 431 onsite visits in 2020/2021. During this time, the EA began using “office-based" inspections to monitor abstraction levels, conducting 1290 during 2020/21. The EA says that these inspections are only used for sites with a low environmental risk and for licence holders with a good history of compliance.

“I’m very concerned by figures that show a decline in inspections and a tendency to replace in-the-field inspections with desk work,” says , who is the chair of England’s chalk stream restoration group. “If anything has shown the need for presence in the field, it has surely been the sewage crisis, which has reached crisis point partly for lack of inspections.”

“Our environment deserves to be properly protected and the EA must be given and must deploy the resources it needs to do that effectively and fairly,” he says.

“Inspections are not our only way of assessing the impact of abstraction on the environment: we have a network of river gauging, groundwater level and ecological monitoring that we use to monitor the impact of abstraction on catchments,” says an EA spokesperson.

“We take a risk-based approach, prioritising this work during drought and prolonged dry weather when illegal abstraction will have the greatest impact on the environment. More widely, we are strengthening the way we regulate, embedding a new approach to drive better performance from the water industry, with additional specialist officers and new data tools to provide better intelligence.”

A novel technique to restore a river to its original state prior to any human intervention – known as stage zero – has been used for the first time at a large scale in the UK.

The method involves completely removing the channel that a river runs through and letting it reconnect to its floodplain, which it may have been historically separated from to make space for roads and railways.

“In the UK, we’ve sadly lost over 90 per cent of our wetland habitat,” said Ben Eardley at the National Trust in a press release.

The conservation charity has completed a three-year project in Somerset to restore a section of the river Aller using the stage zero technique.

The team members did this by filling in a 1.2-kilometre stretch of the river that had historically been artificially deepened and straightened. They moved 4000 tonnes of earth to fill the channel and placed 700 tonnes of fallen timber onto the site to manipulate water flow and provide new habitats in the water body.

The team also sowed wildflower seeds such as wild carrot to attract pollinators to the site. “It’s very abundant in insects, crickets, butterflies, dragonflies and birds [now],” says Eardley.

Most rivers aren’t given the room they need, he explains, but this one has now spread across multiple channels. “We’ve let the river reconnect with the surrounding landscape,” he says.

“This wetland will also hold more water during floods or drought, ensuring it’s better able to cope with extreme weather events or changes in climate, helping local communities and protecting farm businesses,” says Eardley. “It will also help improve the quality of the water by capturing and filtering the water as it runs through the landscape.”

Spot tests have shown that the water quality is already increasing only four weeks after restoration, he says, adding that the new soil environment should also sequester more carbon.

Another project in the Holnicote Estate is the reintroduction of beavers. If the project continues to be a success, it is hoped that the restored river could provide a suitable habitat for them.

Unfortunately, the stage zero technique isn’t particularly scalable in the UK right now. “Landscape scale restoration isn’t very easy to do at the moment in the UK because the regulatory and funding frameworks just aren’t there yet,” he says. “But I was with this project… we’ve learned a lot, and hopefully we can pass that learning and knowledge on and make it easier for projects like this in the future.”

English rivers were pumped with emergency oxygen in a last-ditch effort to save fish from dying on almost 100 occasions in the past five years, �鶹��ý can reveal.

Rivers can become deoxygenated for a variety of reasons, including sewage dumping that encourages the growth of bacteria, plants and algae, which can result in the consumption of oxygen. Hot weather can also play a role, as water holds less oxygen at higher temperatures.

To combat these effects, the Environment Agency (EA) in England has emergency measures in place to pump oxygen into rivers with the aim of preventing fish and plant deaths.

Last year saw 25 instances of the EA doing this, according to a freedom of information request, while there were a total of 74 deployments between 2018 and 2021. The figures for this time period only include 13 out of the EA’s 14 operating areas, and data isn’t yet available for 2023, meaning that while there were at least 99 emergency oxygen deployments in the past five years, the true figure is likely to be higher.

, fisheries manager at the EA, says the organisation hasn’t officially analysed whether the use of emergency oxygen measures has increased in recent years, but says that anecdotally it seems like it has. “It does feel as though the number of reports received of fish in distress has increased over recent years,” he says. “The signs to look out for are fish gasping for air, appearing lethargic in the margins and dead fish floating on the surface.”

The EA pumps oxygen in several ways, such as using liquid hydrogen peroxide, which breaks down into water and oxygen, and mechanical aerators, which increase oxygen in the water body by disturbing its surface. “Used in isolation, mechanical aeration is slower to raise oxygen levels, but it is a great option for chronic issues such as regular algal blooms,” says Storey.

Climate change is likely to increase the need for emergency oxygen in rivers in the future, says Storey. “There are two factors at play here, increasing temperatures and extreme rainfall events acting in combination with underlying pressures on the aquatic environment,” he says. “If global temperatures continue to rise and stay higher for longer periods, this will cause ongoing challenges for wild fish populations and fisheries.”

“The use of emergency aeration shows that fish populations in a number of England’s rivers are on life support,” says at Newcastle University in the UK. “Our changing climate is expected to bring increasingly prolonged periods of low rainfall, which, compounded by sewage and agricultural runoff, could mean that artificial oxygenation becomes the new normal, making our river’s wildlife that little bit less wild.”

“Oxygen pumping is an important emergency measure in fish rescue, but keeping rivers cool, protecting flows and reducing pollution are all important longer-term measures to protect rivers against the impacts of climate change,” says at Cardiff University, UK.