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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Was the decline in Liverpool’s historic population really that unusual?

A view of Liverpool from Birkenhead. Image: Getty.

It is often reported that Liverpool’s population halved after the 1930s. But is this true? Or is it a myth?

Often, it’s simply assumed that it’s true. The end. Indeed, proud Londoner Lord Adonis – a leading proponent of the Liverpool-bypassing High Speed 2 railway, current chair of the National Infrastructure Commission, and generally a very influential person – stood on the stairs in Liverpool Town Hall in 2011 and said:

“The population of Liverpool has nearly halved in the last 50 years.”

This raises two questions. Firstly, did the population of the City of Liverpool really nearly halve in the 50 year period to 2011? That’s easy to check using this University of Portsmouth website – so I did just that (even though I knew he was wrong anyway). In 2011, the population of the City of Liverpool was 466,415. Fifty years earlier, in 1961, it was 737,637, which equates to a 37 per cent drop. Oops!

In fact, the City of Liverpool’s peak population was recorded in the 1931 Census as 846,302. Its lowest subsequent figure was recorded in the 2001 Census as 439,428 – which represents a 48 per cent decline from the peak population, over a 70 year period.

Compare this to the population figures for the similarly sized City of Manchester. Its peak population also recorded in the 1931 Census as 748,729, and its lowest subsequent figure was also recorded in the 2001 Census, as 392,830. This also represents a 48 per cent decline from the peak population, over the same 70 year period.

So, as can be seen here, Liverpool is not a special case at all. Which makes me wonder why it is often singled out or portrayed as exceptional in this regard, in the media and, indeed, by some badly briefed politicians. Even London has a similar story to tell, and it is told rather well in this recent article by a Londoner, for the Museum of London. (Editor’s note: It’s one of mine.)

This leads me onto the second question: where have all those people gone: London? The Moon? Mars?

Well, it turns out that the answer is bit boring and obvious actually: after World War 2, lots of people moved to the suburbs. You know: cars, commuter trains, slum clearance, the Blitz, all that stuff. In other words, Liverpool is just like many other places: after the war, this country experienced a depopulation bonanza.

So what form did this movement to the suburbs take, as far as Liverpool was concerned? Well, people moved and were moved to the suburbs of Greater Liverpool, in what are now the outer boroughs of the city region: Halton, Knowsley, St Helens, Sefton, Wirral. Others moved further, to Cheshire West & Chester, West Lancashire, Warrington, even nearby North Wales, as previously discussed here.

In common with many cities, indeed, Liverpool City Council actually built and owned large several ‘New Town’ council estates, to which they moved tens of thousands of people to from Liverpool’s inner districts: Winsford in Cheshire West (where comedian John Bishop grew up), Runcorn in Halton (where comedian John Bishop also grew up), Skelmersdale in West Lancashire, Kirkby in Knowsley. There is nothing unique or sinister here about Liverpool (apart from comedian John Bishop). This was common practice across the country – Indeed, it was central government policy – and resulted in about 160,000 people being ‘removed’ from the Liverpool local authority area.

Many other people also moved to the nearby suburbs of Greater Liverpool to private housing – another trend reflected across the country. It’s worth acknowledging, however, that cities across the world are subject to a level of ‘churn’ in population, whereby many people move out and many people move in, over time, too.

So how did those prominent images of derelict streets in the inner-city part of the City of Liverpool local authority area come about? For that, you have to blame the last Labour government’s over-zealous ‘Housing Market Renewal Initiative’ (HMRI) disaster – and the over enthusiastic participation of the then-Lib Dem controlled city council. On the promise of ‘free’ money from central government, the latter removed hundreds of people from their homes with a view to demolishing the Victorian terraces, and building new replacements. Many of these houses, in truth, were already fully modernised, owner-occupied houses within viable and longstanding communities, as can be seen here in Voelas Street, one of the famous Welsh Streets of Liverpool:

Voelas Street before HMRI implementation. Image:

The same picture after HMRI implementation Image: 

Nonetheless: the council bought the houses and ‘tinned them up’ ready for demolition. Then the coalition Conservative/Lib Dem government, elected in 2010, pulled the plug on the scheme. 

Fast forward to 2017 and many of the condemned houses have been renovated, in a process which is still ongoing. These are over-subscribed when they come to market, suggesting that the idea was never appropriate for Liverpool on that scale. 

At any rate, it turns out that the Liverpool metropolitan population is pretty much the same as it was at its peak in 1931 (depending where the local borough boundaries are arbitrarily drawn). It just begs the question: why are well educated and supposedly clever people misrepresenting the Liverpool metropolis, in particular, in this way so often? Surely they aren’t stupid are they?

And why are some people so determined to always isolate the City of Liverpool from its hinterland, while London is always described in terms of its whole urban area? It just confuses and undermines what would otherwise often be worthwhile comparisons and discussions. Or, to put it another way: “never, ever, compare apples with larger urban zones”.

In a recent Channel 4 documentary, for example, the well-known and respected journalist Michael Burke directly compared the forecast population growths, by 2039, of the City of Liverpool single local authority area against that of the combined 33 local authority areas of Greater London: 42,722 versus 2.187,708. I mean, what bizarre point is such an inappropriate comparison even trying to make? It is like comparing the projected growth of a normal sized-person’s head with the projected growth of the whole of an obese person, over a protracted period.

Having said all that, there is an important sensible conversation to be had as to why the populations of the Greater Liverpool metropolis and others haven’t grown as fast as maybe should have been the case, whilst, in recent times, the Greater London population has been burgeoning. But constantly pitching it as some sort of rare local apocalypse helps no one.

Dave Mail has declared himself CityMetric’s Liverpool City Region correspondent. He will be updating us on the brave new world of Liverpool City Region, mostly monthly, in ‘E-mail from Liverpool City Region’ and he is on twitter @davemail2017.