Growing up in Doncaster 40 years ago, I barely knew the river that named our town. Keen walkers as my parents were, their rambles studiously avoided the Don. Like an unsavoury or disgraced relative, its name was rarely mentioned. The Don snakes 70 miles or so from the peat bogs and moors of the Pennines through Sheffield, Doncaster, the lost fens of Yorkshire and on to join with the Ouse and the Trent. This is a mighty river. Back in my childhood, however, the Don’s reputation was as tainted as its waters. For more than 200 years it was canalised, culverted and heavily polluted, serving collieries, power stations, mills and, most significantly, Sheffield’s steel industry. Its waters were artificially heated, poisoned with everything from arsenic to lead, and treated as an open sewer. In The Road to Wigan Pier, Orwell wrote caustically of Sheffield’s “ugliness” and the stench of its “bright yellow toxic river”. By the 1960s, the Don was declared biologically dead. When Jarvis Cocker and friend took to its waters in a dinghy in the late 1970s, the singer described the experience as South Yorkshire’s answer to Apocalypse Now. Today the decline of heavy industry and dedicated conservation work along the Don have enabled a remarkable transformation. “It’s time to change the image that the Don is a badly polluted river,” Ian Rotherham, a leading authority on the area’s ecology, tells me. Cleaner waters have brought its birdlife and fish back. Roe, muntjac and red deer have been seen navigating the Don’s waters through Sheffield city centre at night. Water voles and otters have returned. I have returned too – many times now over the years – to walk along its banks, and to seek out its folklore and stories. I am back again to meet some of its guardians, to uncover new pathways and to reconnect with a river that would now be beyond recognition to the young, bespectacled Jarvis. Lower Don Valley Since the creation of the Don Valley Way walking trail in 2018, it’s possible to walk the Don in one 30-mile stretch from Doncaster’s North Bridge to the outer edges of Sheffield, allowing for a few diversions along the way. I’m doing it in sections, using Sheffield’s Blue Loop and the Don Valley Way app, which provides nine circular walks with audio commentary. I begin five miles west of Doncaster at Sprotbrough in the Dearne valley. The riverbank is verdant with willow, ash and alder. The Don shimmers in the sunshine. Willow warblers trill their descending melodies. Warren Draper and Rachel Horne – founders of the mighty publication Doncopolitan – are my guides for what prove to be the most picturesque stretches of the river. We pass a couple easing their inflatable canoe into the water. Teenagers sunbathe on the opposite bank. A family of cyclists whizzes by, towing a drum’n’bass-pounding baby carriage. After the 46-metre high Conisbrough viaduct and distant views of the village’s stunning 12th-century castle, we reach Mexborough, where the Don and its canalised offshoot run parallel. Here both regeneration and industrial decay are evidenced by new riverside apartments and the imposing redbrick former Coltran factory: windows broken and enveloped in an unnatural silence. Draper and Horne – who grew up round here – express their love for walking in the Dearne valley but feel it has yet to catch on in the wider public imagination. The Blue Loop Eight miles in length, the Blue Loop is the longest official circular around the Don, combining Sheffield’s Five Weirs Walk with the Sheffield & Tinsley canal, the two waterways running parallel for several miles into Sheffield city centre. From Meadowhall – a colossal brick shopping centre on the city’s outskirts, known to some as Meadowhell – the river runs to my right, partially occluded by sycamore, alder and Japanese knotweed, one of the many invasive species along the river. The forces of recombinant – hybrid – ecology have also brought mink and the dreaded Himalayan balsam to the Don. Here the eagle-eyed might spot a protected Mediterranean fig forest, the result of the seeds of fig biscuits eaten long ago by former steelworkers being flushed into the Don’s artificially heated waters. At Brightside weir I spot my first salmon pass (fish ladder). Thanks to these and the Don’s increasing health, the river once famous across Europe for its salmon has these fish spawning in its waters again. As I progress towards Sheffield, the landscape becomes more urban. Like the Don, I am diverted and culverted through underpasses, alongside industrial estates and business parks that pepper the fringes of the city. At Walk Mill weir, I rendezvous with Karon Mayor, a British Trust for Ornithology volunteer who is surveying the wetland birds. “My role is to protect what we have left and enhance it where possible,” she tells me. Together we spot herons, lesser black-backed gulls, moorhens and grey wagtails. Nesting sand martins skim fast over the water for insects. Mayor has seen kingfishers, goosanders and dippers on the Don too but is under no illusion of the work still needed. “In summer, the greenery by the riverbank hides much of the waste still carried in its waters.” As well as birds, we spot plastic bags, tyres and a wheelie bin during our hour-long walk – the misfortune of most inner-city rivers. We part by the Tinsley canal, which is, for Mayor, “one of the city’s best-kept secrets”. She’s right (Sheffield boats even does boat trips). Here the environment changes again. The canal is sleepy, the towpath deserted. With cobbled stones underfoot, I pass under limestone railway bridges, meander down its quiet pathway and cross an aqueduct. A bloated orange beast lazily swims past me among the bullrushes. A Twitter call-out reveals it to be a Koi carp, another result of recombinant ecology. Submerged as I am amid walls, fences and foliage here on the towpath, the city is all but hidden from sight. But not sound. The aural landscape of industry rattles trains, clangs metal, blasts air and carries the muffled, disembodied voices of workers. I pass a plethora of locks and a narrowboat community. A group of Ikea staff sit together to picnic by the towpath as Canada geese propel themselves across the water towards them, clearly an established ritual for both parties. Returning to the vast shopping centre I feel as if I’ve soaked up several hundred years’ worth of the Don’s history and ecology on this extraordinary circular. I treat myself to a new pair of socks and an ice-cream. Meadowhall has its uses. Upper Don Valley By Lady’s Bridge in the city centre, Sheffield author and folklorist David Clarke joins me for the Don Valley trail around Kelham Island. Once heavily industrialised, Kelham Island has had the full regenerative treatment, transforming it – Hackney-like – into a fashionable area for bars, cafes and desirable waterside apartments. This area’s rich heritage includes Kelham Island Museum and the site of Sheffield’s 12th-century castle. Clarke points out the entrance to a vast storm drain the Megatron, currently home to the rare Daubenton’s bat. Also overlooking the Don here is Castle House, former home to a Batchelors peas factory where, it is said, Britain’s greatest ever culinary breakthrough occurred in the 1920s: the invention of mushy peas. Alone for the final stretch, I take the Upper Don Trail out of the city to the edge of Hillsborough and its hinterland of light industry. I stand on Wardsend Bridge overlooking the water. It has the perfect clarity and depth for paddling. To my left lies Wardsend cemetery, purpose-built in the wake of Sheffield’s great flood of 1864. The remains of a chapel and hundreds of large tombstones, half-covered in a vivid green moss, nestle in the foliage of a steep hill. Coffins were once carried over the Don here, evoking comparisons with Charon and the River Styx. Back in the mid-1800s a toll was even required for funerals to be able to cross Wardsend Bridge. Totems of money have been offered to our waterways for millennia. It is still considered good luck to toss a coin into a well. Over the centuries we have worshipped, blessed, exploited and polluted the Don’s waters. Only now are we beginning to comprehend what our ancestors knew all along: what we do to nature, we do to ourselves. Rejuvenating the Don, allowing nature to return, is mutually beneficial for our wellbeing, for the good of our souls. We don’t need to prove it with science; we feel it in our bones. Having redefined itself as the “outdoor city”, Sheffield is shifting its focus from the heat of industry to the soul-nourishing qualities of its waterways, green spaces and outdoor pursuits. The city’s steel industry once adopted Vulcan, Roman god of fire and forge, as its mascot. He can still be seen atop Sheffield town hall. But it is Danu, Earth mother and goddess of primordial waters – and from whose name the Don is derived – who we must pay our respects to again. I pick a coin from my pocket, toss it into her shining waters and continue on my way.