Rivers of Change
BURIED BY HISTORY, LONDON’S HIDDEN WATERWAYS COULD SAVE THE CITY FROM A DIRE CLIMATE FUTURE.
In all of western Europe, London stands out as the city most vulnerable to climate change, threatened by both floods and droughts, according to the 2018 Lloyd’s City Risk Index report from the Centre for Risk Studies at the University of Cambridge. London is especially vulnerable because it lies in a lowelevation coastal zone and faces the triple-threat risks of tidal flooding from the North Sea, flooding from the Thames River, and surface-water flooding due to heavy rainfall. What could help protect the city and its 9 million inhabitants from these and other climate crises is a little-recognized resource already in place: London’s hidden underground network of rivers.
While the Thames is likely the best known, London is, in fact, crisscrossed with rivers, a waterway network spanning about 375 miles. Centuries of urban expansion and development literally buried many of these rivers.
But you can still find them if you know where to look, says Tom Bolton, author of the two-volume London’s Lost Rivers: A Walker’s Guide. “I spent quite a lot of time pressed to the drain covers. … You can hear the sound of the water rushing below your feet or you could see through the grating of the drain cover the river below you,” says Bolton. “The cities have been layered above them since they were put below ground, and you end up doing a piece of mental archaeology to recreate the place that this once was, with a river flowing through it.”
If even some of those rivers could be restored to ground level, these long-ignored natural waterways could not only mitigate flood risks but also
The thinking that led to burying rivers in the past is responsible for many of the environmental issues facing London now.
help regulate the city’s microclimate and cool areas down during heat waves, as well as enable several plant and animal species to survive severe weather and pollution conditions.
LOST IN THE FLOW OF HISTORY
London’s rivers have, over the centuries, been hidden behind and beneath buildings, artificially straightened or buried underground, all via pipes or culverts made of concrete and metal. As the city expanded and the population grew, the rivers became increasingly polluted due to industrialization, or were diverted for new uses. The area around the Fleet, the most well-known of London’s lost rivers, gained such a reputation for slum dwellings, crime and disease that it became the inspiration for Fagin’s Den in Charles Dickens’ Oliver Twist.
Some of these waterways were converted into canals, others into sewers. In London today, unless you’re an expert like Bolton, you could be standing within inches of a lost river and not even know it. Queen Elizabeth II, for instance, lives with the Tyburn running directly under Buckingham Palace without any inconvenience. Known for salmon fishing until the 18th century and culverted in 1750, it is now a royal sewer.
“Rivers were put underground generally for three reasons,” explains Adam Broadhead, a water scientist at Arup, a multinational firm based in London that provides engineering, architectural, design and planning services, and an expert in river restoration. “One, because they were polluted, and they were put underground to sanitize them. Two, to control floodwater. Three, so they could allow cities to expand and grow.”
The overarching sentiment since the late 18th century was that the rivers were an environmental hazard rather than an environmental asset. “It was very much a case of reducing the footprint of the water,” says David Webb, chair of the London Rivers Restoration Group (LRRG), a group that brings together several environmental bodies, such as the Environment Agency, the South East Rivers Trust, and the London Wildlife Trust. Their aim is to promote and report on the delivery of river restoration and enhancement projects.
The thinking that led to burying rivers in the past is directly responsible for many of the environmental issues the city is currently facing. “In the past, you’d get an engineer with this very linear kind of view who’d want to get rid of the river without considering there may be some landscape value, some wildlife value, or some cultural value that’s being ignored,” says Webb. To that end, LRRG and
If even some lost rivers could be restored to ground level, they could help mitigate floods and cool areas down during heat waves.
its supporters have been proposing plans to restore London’s rivers.
UNCOVERING PAST WATERWAYS
This urban rewilding of rivers is typically done through a process called daylighting, which returns a culverted or covered river to open water. This can involve varying degrees of engineering, earthmoving and landscaping work to create surface channeling that returns an underground river at least in part to a more natural form. The process often requires a change in the land use and ownership, and is therefore difficult and sometimes impossible to do. This is especially true in dense urban areas like London, where logistical, economical and historical considerations would create insurmountable challenges. (To pick just one example: The Royal Family are not likely to level or move Buckingham Palace just so the Tyburn can flow freely again.)
And yet, restoring some of London’s lost waterways is not entirely impossible, thanks in part to efforts and funding from government and nonprofit
organizations. In the past decade, nearly 25 miles of rivers have been restored across the city.
The Wandle in South London, which had been widened and straightened, suffered from pollution run-off from factories that closed in the 1980s and 1990s. In 2015, the river’s ecosystem was restored, and brown trout returned to the river for the first time in 80 years.
The lost River Moselle at Lordship Recreation Ground in Tottenham was daylighted in 2012 as part of a project to re-landscape the park, creating a quarter-mile of meandering river with backwaters and a patchwork of floodplain habitats. The project was funded by nonprofits as well as the U.K.’s Environment Agency, the Greater London Authority, and local leaders. The naturalized channel can store more floodwater, and its meandering path now slows the river’s flow to reduce flood risk, according to a report from London Rivers Week, a local independent charity that works with communities to improve rivers and canals.
And then there’s the River Quaggy in Sutcliffe Park. The waterway’s partial restoration in 2005 by the Environment Agency and Quaggy Waterways Action Group led to an increase in park visits by 73 percent, with the total time spent in the park per person per month increasing by more than 3.5 hours. The regeneration has further helped protect 600 homes and businesses in the London boroughs of Greenwich and Lewisham from future flooding.
One of the most successful examples of this daylighting, however, is the Mayesbrook Park river restoration site in East London. The idea was to update the park’s 50-year-old flood management infrastructure using a green approach that would establish natural flood storage, as well as regenerate the park by creating opportunities for play and access to nature. According to an Ecosystem Services Assessment conducted by the Environment Agency in cooperation with Queen Mary University of London, which quantified the benefits from all of the proposed restoration work in Mayesbrook in 2010, the estimated long-term return to society from the restoration project was valued at £7 for every £1 spent on the project. (That’s nearly a $10 return for around every $1.50 spent.)
THE PAST PROTECTS THE FUTURE
“There are definite economic benefits and that is probably where you’ve got the best chance of restoring these rivers in cities,” says Broadhead. Making the rivers a feature of their communities increases commercial opportunities in the space; well-being benefits add up too, in terms of reduced health costs and more productivity.
“If you take a strategic view about where these lost rivers are and, rather than trying to do it all at once, break it up, you’ll find that, from generation to generation, little plots of land come available and you can take those opportunities,” says Broadhead. This is already being done in some areas, when industrial buildings become derelict and housing developers are allowed to redevelop the site — on the condition that they open the culvert and make the river a feature. For developers and landowners, explains Broadhead, this can be a very useful thing to do. The culverts are decades, and in some cases, over a century old, and will reach the end of life at some point, costing hundreds of thousands or even millions of pounds to repair and replace.
There’s the potential for as much as 60-plus miles of London’s rivers to be restored by 2050, according to estimates by the LRRG. If these were to be restored, the impact on the city would be transformative, says Webb. “When you do a river restoration, you’re immediately creating new habitats,” he says. “What you’re doing is creating more space for species that already exist in the river, you’re increasing their footprint, the habitat envelope in which they can exist. … It makes the population more resilient to extreme events.”
These hidden rivers, with such relevance in the city’s history, could play a crucial role in protecting its future as well. Says Bolton, “The reality is that [rivers are] a very important … environmental asset that we’ve lost, and there’s a real incentive now to try and fix that.”
In the past decade, nearly 25 miles of hidden rivers have been restored, with the potential to uncover 60+ miles by 2050.