The thick mist hangs low over the high moor where the river rises from a boggy wilderness. It rushes over granite slabs and waterfalls down rocks, pooling alongside small oaks amid the coconut tang of yellow gorse, before picking up pace once more, fed, at last, by a few days of rain. Twenty-three miles downstream its brackish flow swooshes at pace into a steep-sided estuary where paddleboarders ride the tidal motion and surfers run into the swell of Bigbury Bay. On its journey from the highest reaches of south Dartmoor in Devon, the River Avon plays host to egrets and herons, entertains anglers seeking brown trout and salmon, offers open water for swimmers and lays out its banks for paddling children and picnicking hikers. Witnesses to its journey change over the years, but it remains, seemingly a constant force, rising from its source and pulled by gravity to the sea. “Physically it hasn’t changed much at all since I first started fishing it 30 years ago,” said John Roberts, the chair of the Avon fishing association. “To me it is beautiful, much of it is still untouched and I love to be on it. It is just a peaceful, calming place.” Solace for so many, the river sits in an area of outstanding natural beauty and its estuary is a marine conservation zone. And yet, despite appearances, it is not immune to the threats and pressures that endanger so many British waterways. Over the last few years the UK’s rivers have been gripped by a deepening crisis, with a chemical cocktail of sewage, agricultural waste and other pollution suffocating biodiversity and risking public health. . The Avon fails water quality tests that measure how close it is to its natural state. It suffers from pollution, high phosphate levels, low flows, high temperatures, flash floods, drought and obstructions to its natural movement. While the likes of the Wye in Wales exhibit their distress visibly with foggy waters the colour of pea soup, the stress on the Avon may not be so immediately stark. “In Devon we don’t have examples like in the River Wye where there are these visible algal problems because our rivers are shorter and faster flowing, but these issues are very much present and they are passed on to the estuary and coastal environment,” said Simon Browning, of the Rivers Trust. The first sign of a river in distress is often found in its fish and the Avon, known also as the Aune, is no different. Roberts has witnessed the drop off in salmon numbers in the past 10 or so years. “The issue for us all is the decline in the salmon population,” he said. “In 2010, our association caught 56 salmon. Last year, there were only four caught and I think that tells us a lot about the factors affecting the river itself.” Downstream from the river’s source on a flank of Ryder’s Hill on Dartmoor, the Avon Dam looms, holding back the river into a vast reservoir that can contain 1,313m litres of water. Built in 1957 to provide water for Plymouth and the surrounding areas, it is testament to how vital the Avon’s waters are for the local population. After the driest July for more than 100 years, water levels are noticeably low. For the habitats and biodiversity of the river itself, though, the dam is an obstruction and a pressure, one that contributes directly to the drop in salmon populations. “The Avon Dam limits the natural flow of the river and stops the movement of gravel down it for salmon to spawn in,” said Dr Laurence Couldrick, the chair of the Westcountry Rivers Trust. Couldrick and his team do their bit to help, adding granite gravel to the river below the dam, which is carried downstream with the flow, providing a place for the fish to spawn when they come upriver. “The problems for a river like the Avon are multifaceted and very complicated, and as a society it is easy to focus on just one thing, at the moment that is drought, in another few months it will be flood risk, then water pollution, but it is all interconnected, it is all pressure on a river,” he said. Others along the Avon’s path intervene to help as it rushes along. At South Brent, a large village, the waters part around an island, a focal point since it was bought by the community in 1994. Guy Pannell, a parish councillor who helped raise money to buy the land, said the efforts of local people have created a fish passage through a weir to help the salmon; a mark of their closeness to the Avon and concern for its waters and habitats. “It is a wonderful river, we have trout and otters and you can watch the salmon leap as they move upstream, we have spotted kingfishers and dippers. We are here to protect it and to make sure it can continue to be enjoyed.” Along with low river flows and obstructions, pollution affects the species and local industries the Avon can support. There are three South West Water treatment plants, as well as combined sewer outflow pipes, along the river. Dr Stuart Watts, the chair of Aune Conservation Association, has warned on its Facebook page that releases of raw sewage into the river are “an intolerable public health situation because the upper estuary is used ever more frequently by wild swimmers, SUP [standup paddleboarding] users, canoeists and the like.” According to Environment Agency figures, raw sewage and wastewater – which should only be released in exceptional circumstances – were discharged into the Avon via storm overflows for 1,355.5 hours in 2021 in 237 separate incidents. South West Water admits in documents that “overflows in this catchment may impact on the following bathing beaches/shellfish waters; Bantham Beach, Avon”. For one industry, oyster farming, the impact of pollution has been devastating. Thirty-three years ago, popular restaurant the Oyster Shack was born when seafood lovers came in large numbers to buy fresh produce from the farm in the Avon. Today, the new owner, Kieron Vanstone, can no longer source oysters from the Avon, as the levels of E coli in the river have led to its classification being downgraded to the lowest rating of C for much of the year. “It is sad and disappointing,” said Vanstone. “You can see the river from the restaurant and I wanted to have them from the Avon, but we have not been able to.” As well as releasing untreated sewage, the wastewater treatment works at Aveton Gifford, a village that sits at the top of the Avon estuary, and further upstream at Loddiswell and South Brent, discharge their treated sewage into the river after testing and monitoring carried out by the water company itself. It is a testing regime that some believe is too light touch. “South West Water has to submit results from 12 samples a year at Aveton Gifford, but they are only testing for a couple of things – it is a very, very low bar – so some of the things that water users are most concerned about, like levels of phosphate and bacteria, are just not being monitored,” said Browning. According to the Rivers Trust, the water sector contributed to more than half of English river water bodies (53%) failing to achieve good status in 2020 from treated and untreated sewage. Along its route the Avon flows through a steep-sided valley, grazed by cattle and planted with crops and woodland. For 10 years Lynne Kenderdine, of the Devon Wildlife Trust, has climbed her way up and down the river landscape to work with farmers and landowners. “My work is totally focused on getting the best deal for the environment,” she said. “We have had issues with runoff into the river. Some really big barns have gone up with large numbers of dairy cattle and inappropriate application of slurry, as well as crops like rye grass which need chemicals and fertiliser, being grown on a steep-sided valley, so there is more work to be done.” While its source is on a lonely Dartmoor hill, the Avon’s odyssey comes to an end by the beaches of Bigbury Bay, where thousands of holidaymakers gather to surf, swim and play. Here the land, the river and the beach are managed by the Bantham Estate, which says the farmland is carefully managed to enhance the beauty and wildlife in the area. “The management of the river goes along with that,” said Nicholas Johnston, the owner of the estate. “It is about responsible, sustainable access at a time when water sports, paddleboarding and swimming are hugely popular. South West Water makes a huge amount of money and it should not be beyond their capabilities to find a solution to stop them putting foul water into the river. I am immensely concerned if there is potential for untreated or treated sewage to impact on water quality as far down the river as this.” Two days after the first rainfall for months, his worries are starkly illustrated by a small yellow notice at Bantham beach. “This bathing water is subject to short-term pollution … a pollution risk warning is issued if heavy rainfall occurs to enable bathers to avoid periods when bathing water quality may be reduced.” A South West Water spokesperson said: “As part of our commitment to protecting the natural environment, we are delivering our largest environmental investment programme in 15 years. This will dramatically reduce our use of storm overflows, maintain our region’s excellent bathing water quality standards all year round, and remove our impact on river water quality by 2030.”