Why saving Britain's rivers means more than cleaning up sewage

UK policy-makers must deal with far more than sewage if they want to save the country’s rivers, researchers have warned.

Last week, river practitioners and scientists congregated at the UK’s annual River Restoration conference in Birmingham. The recurring theme of the two-day gathering was that officials and the general public are too focused on the excessive amounts of sewage discharged by water companies, and not enough on the fact that nearly all of the UK’s rivers are in an unnatural state.

“Even if you solved all the sewage and farming pollution affecting the UK’s rivers, you’d only solve half the problem,” Marc Naura at the River Restoration Centre in Cranfield, UK, and one of the organisers of the event, told New Scientist.

Just 3 per cent of the UK’s rivers flow unobstructed, according to a European Union project. “Through time, rivers have been straightened, widened and often lined with concrete, which provides little variety of habitat for aquatic wildlife,” says Bella Davies at the South East Rivers Trust, a conservation body.

“Imagine you’re a fish in such a straight concrete channel, when it rains and water runs off land and into rivers, you’d be faced with a wall of water which would be hard to swim against with nowhere to hide – you’d get washed downstream and out of the river,” says Davies. “Over time the fish population disappears as there’s nowhere to live, no river gravels and vegetation to lay your eggs, and the river structure doesn’t support the diversity of aquatic insects you’d need to eat.”

While it is often cited that just 14 per cent of England’s rivers achieve good ecological status, it is less noted that the most common reason that rivers don’t achieve this designation is due to physical modifications – 41 per cent of England’s waterways fail on this measure.

Rivers were historically straightened to make way for roads and railways with little consideration for the impact on wildlife, says Chris Spray at the University of Dundee, UK.

“Many freshwater fish species, such as Atlantic salmon and trout, not only require cool, clean water in which to live, but also rely on natural river processes that provide clean gravels and boulders in which to lay their eggs, hide from predators and to find food,” says Craig MacIntyre at the Esk District Salmon Fishery Board in Brechin, UK.

That is why many people at the conference were discussing solutions for restoring rivers to a more natural state. One is re-meandering, in which artificially straight rivers are bent again, restoring their natural flow. This increases the volume of water carried by rivers, which in turn reduces the risk of flooding and creates multiple types of water flow in the river, leading to a greater diversity in aquatic life, says Spray.

What we can do to let the UK’s tamed rivers flow wild and free again

In the UK, 97 per cent of rivers have been modified, blocked and otherwise corralled to suit our needs - with enormous damage to wildlife. Here’s how we can reverse the damage we’ve done

Last year, the UK’s Department for Environment Food & Rural Affairs (Defra) launched the Landscape Recovery scheme. This isn’t specific to rivers, but half of the 22 projects funded as part of it involved restoring the natural processes of rivers and streams. These cost around £400,000 each. Defra plans to expand the scheme and pay for 25 more projects in the coming months.

D-J Gent at the UK’s Environment Agency told the conference it hopes to pay for 200 such projects by 2030. These will be funded by fines levied on water companies for various rule infringements, such as the illegal discharge of sewage.

But many people at the conference said such money alone wouldn’t be enough to tackle the artificial state of many of our rivers. David Sear at the University of Southampton, UK, hopes that more funding will come if the public better understands the severity of the issue.

“The general public doesn’t even know that most of our rivers are physically modified,” he says. “People have grown up with rivers that look artificially straight and have weirs,” he says. “And so it doesn’t seem abnormal.”