Berlin offers a model for how cities can cope with increasingly regular extreme floods

Flooding in Texas after Hurricane Harvey grew to be one of the most damaging Atlantic hurricanes in recent years. Image: US Army Photo.

We’ve become accustomed to quasi-apocalyptic images of cities swapping streets for rivers.

Typhoon Hato led to deluges in Hong Kong and Macau, causing £757m and £1.1bn worth of damage, respectively. Hurricanes Irma, Maria, and Jose battered the Carribbean and the south-easternmost states of the United States, while Hurricane Harvey was devastating to coastal areas of Texas.

Houston, Havana, Roseau, Miami, San Juan, St John’s – the list of cities overcome by water and wind this year is a long one.

Even aside from such dramatic events, abnormal rainfalls have caused extraordinary floods in several cities across the world.

Mumbai and Dhaka were just two cities caught up in the vast flooding across India, Nepal, and Bangladesh, which killed at least 1,200 people and put one-third of Bangladesh underwater.

Cities across central and southern China – from Chongqing to Changsha, down into Duyun and Jiangxi province – saw serious flooding, with more than 18,000 homes destroyed.

Flooding in Mumbai in August 2017. Image: News Measurements Network Live.

In Quebec in Canada, nearly 2,500 homes were flooded across Montreal and Laval, while Paris, Berlin, and parts of Switzerland have all spent time partially underwater recently. Images from the French capital, where water gushed and danced down the steps into metro stations, were particularly striking.

One neighbourhood in Berlin is trying to ensure that cities can become better-adapted to the increasing likelihood of extraordinary wet weather events.

The theory rests on the logical foundation that cities are inherently unnatural. By smothering the earth in concrete and tarmac and loading it up with vast structures of brick, steel, and glass, cities interfere with the way nature regulates itself.

The concentration of buildings, people, and activity increases temperatures – while tarmac and concrete surfaces naturally absorb, retain, and emit heat, only pushing the mercury higher.

On the aquatic side of the equation, unnatural, man-built road and pavement surfaces stop any falling water absorbing into the ground and then naturally providing moisture for soil and vegetation during dryer periods, while also evaporating to provide a kind of natural air conditioning.

The area of Rummelsburg in the city’s east, was built 20 years ago and serves as an exemplary model of the ‘Sponge City’ concept – ‘Stadtschwamm’ in German.

Rummelsberg, from ground level. Image: Lotse.

Buildings are wrapped in green walls, roofs, and garden terraces, with thick tranches of soil up to 80cm deep, while roadside trenches between pavements and streets create a miniature urban wetland, which can retain water and both feed it into the water table and evaporate it to keep the city cool.

During heavy rainfall, the thick layers of greenery handle the water better than the conventional concrete-and-drainage system. There’s less likelihood of drains overflowing because they’re blocked or merely overwhelmed, and pavements are less likely to be transformed into temporary white water rafting courses.

The system is also better for water quality in lakes and rivers. During extreme weather events, the grit and grime of urban living can be swept straight into these bodies of water, where unnatural substances can harm animals and plants, and natural materials like pollen and leaves can overwhelm marine life by giving them too many nutrients in one go.

While it’s a great idea, of course, it can be hard to put into practice. While many cities – London included – are on a splurge of building new developments that often conform to higher eco-friendly standards (and could be encouraged, or mandated, to conform to ‘Sponge City’ design benchmarks), the vast bulk of prohibitive surfaces have already been built.

The cities of the UK, for example, already have their streets, pavements, tiled and concrete roofs – so retrofitting is the order of the day. This can be more expensive, more difficult, and can be tricky to incentivise. And while there could be profiteering enticements – a building with an accessible green roof is likely to be more interesting and appealing to buyers and renters, and public or commercial buildings could grow produce in these spaces – it’s unclear whether that will be a significant enough boon.

Nonetheless, as extreme weather events become less out of the ordinary, adapting our greatest centres of population to better accommodate the demands of nature seems like common sense – even if it does mean boggy pavements.

Jack May is a regular contributor to CityMetric and tweets as @JackO_May.

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Leeds is still haunted by its pledge to be the “Motorway City of the Seventies”

Oh, Leeds. Image: mtaylor848/Wikimedia Commons.

As the local tourist board will no doubt tell you, Leeds has much to be proud of: grandiose industrial architecture in the form of faux-Egyptian temples and Italian bell-towers; an enduring cultural legacy as the birthplace of Goth, and… motorways. But stand above the A58(M) – the first “urban motorway”  in the country – and you might struggle to pinpoint its tourist appeal.

Back in the 1970s, though, the city council was sufficiently gripped by the majesty of the motorways to make them a part of its branding. Letters sent from Leeds were stamped with a postmark proudly proclaiming the city's modernity: “Leeds, Motorway City of the Seventies”.

Image: public domain.

During the 1960s, post-war optimism and an appetite for grand civic projects saw the rapid construction of motorways across England. The construction of the M1 began in 1959; it reached Leeds, its final destination, in 1968. By the early 1970s the M62 was sweeping across Pennines, and the M621 loop was constructed to link it to Leeds city centre.

Not content with being the meeting point of two major motorways, Leeds was also the first UK city to construct a motorway through the city centre: the inner ring road, which incorporates the short motorway stretches of the A58(M) and the A64(M). As the council put it in 1971, “Leeds is surging forward into the Seventies”.

The driving force behind Leeds' love of motorways was a mix of civic pride and utopian city planning. Like many industrial cities in the North and Midlands, Leeds experienced a decline in traditional manufacturing during the 1960s. Its position at the centre of two major motorways seemed to offer a brighter future as a dynamic city open for trade, with the infrastructure to match. In response to the expansion of the roads, 1970s council planners also constructed an elevated pedestrian “skywalk” in an attempt to free up space for cars at ground level. Photos of Leeds from that time show a thin, white walkway running through blocky office buildings – perhaps not quite as extensive as the futuristic urban landscape originally envisaged by planners, but certainly a visual break with the past.

Fast forward to 2019 and Leeds’ efforts to become a “Motorway City” seems like a kitsch curiosity from a decade that was not always known for sustainable planning decisions. Leeds’s historic deference to the car has serious consequences in the present: in February 2019, Neville Street – a busy tunnel that cuts under Leeds station – was found to contain the highest levels of NO2 outside London.

City centre planners did at least have the foresight to sink stretches of the inner motorways below street level, leaving pedestrian routes largely undisturbed. Just outside the centre, though, the roads can be more disruptive. Sheepscar Interchange is a bewildering tangle of arterial roads, Armley Gyratory strikes fear into the hearts of learner drivers, and the M621 carves unsympathetically through inner-city areas of South Leeds with pedestrian access restricted to narrow bridges that heighten the sense of a fragmented landscape.


Leeds inner ring road in its cutting. Image: author provided.


The greatest problem for Yorkshire's “Motorway City” in 2019, however, is not the occasional intimidating junction, but the complete lack of an alternative to car travel. The dire state of public transport in Leeds has already been raised on these pages. In the early 20th century Leeds had one of the most extensive tram networks in the country. The last lines closed in 1959, the same year construction began on the A58m.

The short-sightedness of this decision was already recognised in the 1970s, as traffic began to build. Yet plans for a Leeds Supertram were rejected by successive Conservative and Labour governments unwilling to front the cost, even though smaller cities such as Newcastle and Sheffield were granted funding for light transport systems. Today, Leeds is the largest city in the EU without a mass transit system. As well as creating congestion, the lack of viable public transport options prevents connectivity: the city's bus network is reasonable, but weaker from East to West than North to South. As a non-driver, I've turned down jobs a short drive away that would be a logistical impossibility without a car.

Leeds' early enthusiasm for the motorway was perhaps premature, but there are things we can learn from the 1970s. Whatever else can be said about it, Leeds' city transport strategy was certainly bold – a quality in short supply today, after proposals for the supertram were watered down to a trolleybus system before being scrapped altogether in 2016. Leeds' rapid transformation in the 1960s and 70s, its grandiose visions of skywalks and dual carriageways, were driven by strong local political will. Today, the long-term transport strategy documents on Leeds City Council's website say more about HS2 than the need for a mass transit system within Leeds itself, and the council has been accused of giving up the fight for light rail and trams.

Whilst central government's refusal to grant funds is the greatest obstacle to Leeds' development, the local authority needs to be far more vocal in demanding the transport system the city deserves. Leeds' desire to be the Motorway City of the Seventies might look ludicrous today, but the political drive and utopian optimism that underpinned it does not.