Walking along the banks of the Emscher, the Tyczkowskis recall that it was the stench which most vividly defined the river’s darker days.

“The whole thing was filthy and it stank terribly,” says the couple, a retired watchmaker and tax adviser in their 80s. Were they ever tempted to take a dip? “No,” they laugh in disgust. “There were other things swimming inside.”

For over a century, foul fumes rose from what was known as the “sewer of the Ruhr”, spreading a pungent odour across Germany’s industrial heartland. Today, however, the Emscher bears little resemblance to what was once considered Europe’s dirtiest river.

Water that was previously polluted with industrial waste and human sewage has been free of effluent since 2021. The river system – the main stretch of which was once thought biologically dead – is now witnessing the return of vibrant life.

Nature lovers have spotted lapwings, kingfishers and demoiselle damselflies in the region, along with freshwater shrimp, caddisflies, and even beavers. In May, scientists reported that red-finned rudd from the Rhine had re-established themselves in the area.

“Overall, it is really a success story,” says Prof Daniel Hering, an aquatic ecologist at the University of Duisburg and expert on the river’s ecology. “In former times, it was a sewer. Now, it is a river.”

The Emscher flows through the heart of Germany’s densely populated Ruhr region, a rusty sprawl of towns and cities that emerged around coal mines and factories during the Industrial Revolution. In the 19th century, the fast-growing population suffered from waterborne diseases such as typhoid and cholera, which claimed the lives of many workers and hindered the economic boom.

Alarmed by the impact on profits, the Ruhr’s industrial barons took steps to improve public health. Alongside local authorities, they founded the Emschergenossenschaft – the country’s first water management association.

However, engineers were unable to construct underground sewage canals, as the coal mining activity caused unpredictable ground subsidence. Instead, they chose to discharge the waste into the meandering Emscher, which they straightened and lined with concrete.

It wasn’t until the collapse of the coal mining industry in the 1980s, which halted the subsidence, that politicians began to seriously consider reviving the river.

“My predecessors, who were engineers, at first asked: ‘Why? It all works fine,’” says Uli Paetzel, the chair of the board of Emschergenossenschaft and fellow water management association Lippeverband. “But there was also an increase in environmental awareness after the Chornobyl crisis and the die-off of seals in the North Sea, which really troubled the German population.”

The Emschergenossenschaft embarked on the monumental task of cleaning up a river that had functioned as an open sewer for more than 2.5 million people. It constructed a central 51km sewage “motorway” with an internal diameter of 2.8 metres – “you could drive a car through it, it’s that big,” says Paetzel – as well as numerous pumping stations, four treatment plants, and 436km of sewage channels.

The €5.5bn (£4.7bn) scheme was largely financed by fees from industry and local communities, with around 20% coming from the EU and the state of North Rhine-Westphalia. Backed by low-interest loans from public banks and supported by residents keen to be rid of the summer stench, the enormous restoration effort progressed with minimal resistance. Remarkably, the project faced no legal challenges – a rarity in Germany, according to Paetzel.

“The biggest hurdle was technical,” he says. “Putting underground canals into a densely built-up region – with motorways, dense urban development, industrial facilities – and getting the land to do so, that was the biggest challenge.”

Today, the Emscher supports thriving wildlife and provides a vibrant blue-green corridor for residents and visitors in a post-industrial region long affected by poverty and unemployment. More than 130km of cycle paths now run alongside the river.

The water is so clear that “sometimes, from the bridge, you can even see down to the riverbed”, says Volker, a retired lawyer, as he and his wife take a break from their bike ride to admire the view. “We both find it so nice that it was restored.”

Few rivers in Europe have undergone a transformation as dramatic as the Emscher’s, though many of the continent’s rivers and lakes remain in dire need of attention. A report by the European Environment Agency in October found that only 37% of surface water bodies had a “good” or “high” ecological status, and just 29% achieved a good chemical status – figures that had “hardly changed” between 2015 and 2021.

Interest in river restoration has grown as governments face increasing pressure to protect nature, and concepts such as “rewilding” have entered the mainstream. The EU has pledged to restore 25,000km of rivers to a free-flowing state by 2030.

In the Emscher’s case, however, the extreme subsidence in the region means the river has not been returned to its original course.

“Restoring the Emscher to its former state is a task that cannot be done,” says Monika Raschke, a water expert at the non-profit German Federation for the Environment and Nature Conservation (Bund) – though the cleanup has brought back plants, insects, fish and birds. “It’s not the absolute ecological highlight that we might have elsewhere, but of course it’s a huge improvement.”

Hering notes that the river’s recovery is still ongoing. Smaller streams, which were never as heavily degraded as the main waterway, are already teeming with life – but the Emscher itself may require another decade before stable ecological communities become fully established.

“With the tributaries, we have a pretty good idea of how re-establishment happens,” he says. “With the main river, Emscher, which has been sewage-free for three years, we are only at the beginning of this process.”

Nevertheless, Hering says, the project offers valuable lessons: that nature is capable of recovery, even from the bleakest of starting points; that large-scale initiatives can succeed when they are embedded in the wider community; and that wildlife needs time – often years – to rebuild stable habitats.

“It takes time. But immediately after restoration, of course, you’ll see the first signs of success.”

 

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At Natural World Fund, we are passionate about restoring habitats in the UK to halt the decline in our wildlife.