An urban waterway is more than just a short cut through the city – it’s a testament to the power of nature over neglect

The roar of the road is receding with each step down and with it the light is changing; it is dancing, mirrored and then dappled in the ripples of the water. One layer down and the city has become an entirely different place.

I, like many, am using the canal as a quiet cut-through. It smells different down here; there’s the dankness of the water, for sure, but there’s a wealth of green filtering the fumes from above. And the soundscape changes – song birds, the curious grunt of a bank of geese eyeing me and the dog warily, the lap of the water’s edge and the groan of metal sidings that are there to repair the bridge.

The wild nature that sprouts from the cracks in the towpath and between the bricks in the bridges is in spite of us

Today the canal is a shortcut to another part of the city, but the canals also represent an escape for me. There’s a freedom to this space that feels unpoliced by normal city rules. When I am kayaking they become an adventure playground, a way to get to part of the city you can’t reach on foot. A place to meet fellows, human or otherwise, that you might not find elsewhere.

The life down here is distinctly feral. There are men fishing, some for fish, some for metal. I’ve seen a man using a huge magnet on a thick line of rope to trawl the canal floor for treasure. There’s a trail of unwanted, rusting finds; a child’s bike, a spanner, bolt cutter, a pulley, rod bars and what looks like a rotting safe, a screwdriver, endless bike locks and a horse shoe. The archaeology of the canal in rusted orange.

Q&A What is the canal revolution series? Show Hide Few things symbolise the way our cities have transformed more than canals. Around the world, cities have woken up to the power of their urban waterways: from Milan to Manchester, the former economic arteries of industry are being turned into corridors for walkers, boaters and wildlife. Cafes and restaurants are proliferating and canalside living is newly chic – and newly costly. As commercial interests muscle in on the last great undeveloped bit of Britain’s cities, Guardian Cities and the Observer wanted to take stock of a crucial moment in history, when we still have a choice: whether to turn canals into sanitised enclaves of wealth, or preserve them as a precious resource for all. Chris Michael, Cities editor

The horse shoe will no doubt date to the 18th century, when barges were towed by horses, ponies, donkeys and mules. The pulley from a warehouse loading bay and the bike locks symbolise something eternal about canals, they can hide a multitude of sins and secrets.

The wildlife is feral, too, for however pretty and picturesque the towpath edge appears, fecund in dog roses and elder, thick with blackberries, buddleias and alders and waterlilies, it is also uncultivated, these wild things taking back the margins.

Facebook Twitter Pinterest Alys Fowler: ‘When I am kayaking, the canals are a place to meet fellows, whether human or otherwise, that you might not find elsewhere.’ Photograph: Laura Pannack/Guardian

Some are distinctly prosaic, dandelions and verges of selfheal, and others utterly unexpected – a bank of redcurrants dangling over the water, a thicket of figs full of fruit and an untamed apple orchard from thrown-away cores.

This wild nature that sprouts from the cracks in the towpath and between the bricks in the bridges is in spite of us. For these are some of the most heavily polluted areas we’ve created in cities.

At the height of their construction in the 18th century, canals ran like trunk roads, zigzagging across the country, following natural contours but serving the greatest catchment area for trade purposes. You can roughly date a canal to pre- or post-1750s by whether it is narrow and meandering or ramrod straight and wide.

Facebook Twitter Pinterest A print showing a barge passing by gasworks on Regent’s canal, London, 1828. Photograph: Ann Ronan Pictures/Print Collector/Getty Images

The more experienced and sophisticated engineers, such as Thomas Telford and William Jessop, constructed less scenic but more efficient canals that cut a straight line through, rather than around, obstacles using aqueducts, tunnels, high embankment and deep cuttings. They were shorn out of the industrial revolution’s landscape, giving them their nickname the Cut, as they were blasted through Triassic rock faces.

Where today we might see banks of trees towering over the water, there would have been wall-to-wall buildings, the air thick with coal smoke and the water full of factory run-off. The bottom layer of silt in the canal is still full of heavy metal pollution from the period.

We are merely gentrifiers: the hard work has been done by many things down in the dark recesses of the canal

For this reason, the water is both beguiling and disturbing. In the right light it is as pretty as can be, dazzling the red brick buildings around it, bouncing light into hidden corners, beckoning you forth. But stare too deeply into its depth and you glimpse its murky otherworld. For a long time in Birmingham, the canals were known as Dead Dog Ditch. They have unforgiving sides with deep ledges that are not meant for climbing out of, and there are countless tales of souls lost to the water.

In modern history the canals have been claimed by runners and canoeists, by cyclists and strollers as valuable green spaces in cities. But we are merely gentrifiers of our own forgotten space: the hard work has been done by many things down in the dark recesses of the bottom of the canal. Duck mussels filtering through the heavily polluted industrial sludge, cleaning the water as they sup, waterlilies pumping oxygen down to the root layer so that small water creatures can creep, and carp, bream, rudd and roach can dart away from predators such as pike and eel. And with these come kingfishers, water voles and shrews, cormorants and the long, heavy swoop of grey herons.

Nature has reclaimed her ground in our most polluted industrial areas, a testament to her powers over our neglect.

For me the joy of visiting the canals is that they are not static spaces, they are vibrant in summer, reflective in autumn and frankly too cold for paddling in winter, but they are like old friends. I hope their feral nature is never taken for granted.

The canal revolution series looks at what our changing waterways reveal about modern British cities. Follow Guardian Cities on Twitter, Facebook and Instagram and use the hashtag #canalrevolution to join the discussion or sign up for our weekly newsletter