The Future Cities project

promoting a human-centred approach to nature

Two Cases for the (Floods) Defence

‘Atlas of the New Dutch Water Defence Line’ (010 Publishers) & ‘Facing up to rising sea levels (Building Futures, RIBA)

Reviewed by Austin Williams | February 2010

Contrary to the implication in its title, the Atlas of the New Dutch Water Defence Line has nothing to do with global warming and flood management. The book is a historical assessment of the network of watercourses known as the Nieuwe Hollandse Waterlinie (NHW) and “defence” refers to defence by water rather than from water.

During the 17th century War of Independence against Spain, Maurice of Orange Nassau flooded low-lying areas as a foil to enemy troops. It was so successful that, from 1629, an colossal construction project of sluices, canals, polders and fortifications was begun… and building work continued for another 350 years! Colonel Merkes van Gendt is quoted as saying, “Only Holland can be made unassailably strong through nature and engineering.” It was only at the end of the 19th century that it became apparent that natural defences were no match for modern seige artillery.

Commissioned by the NHW restoration project, this intriguing book contains several short essays, a few black and white photographs, and a huge number of ordinance maps of varying size and complexity. Each map is eminently browsable and conveys the magnitude of the project under review. The Atlas celebrates the NHW as an anachronistic folly, a historical archive, a national treasure, but predominantly as a remarkable human attempt to transform nature and bend it to human will.

Conversely, the latest report by the RIBA’s think-tank, Building Futures, in association with the Institution of Civil Engineers seems to be in thrall to nature. Facing up to rising sea levels: the future of our coastal cities takes it as read that we should be uniquely concerned about rising tides. It’s all part of “reconnecting people and water” apparently.

“Sea levels are unmistakably rising”, it says and indeed, the IPCC report “Climate Change 2007: The Physical Science Basis” confirms that average global sea levels may rise by up to 580mm over the next 100 years. However, it also cautions that this might be as low as 220 mm (and that regional variations might be a mere 70 mm). There are many other provisos that need to be added. For example, the IPCC states that “Many ocean observations are poorly sampled (and)… observational records only cover a relatively short period of time (e.g., the 1950s to the present)… and in some cases decadal variability and/or poor sampling may prevent detection of long-term trends’. The government’s “UK Climate Projections” (UKCP09) states merely, that the “sea level around the UK rose by about 1mm/yr in the 20th century” although “this is predicted to be higher in the 21st century”. Leaving aside the fact that UKCP09 gets it data from the somewhat discredited University of East Anglia, it is fair to say – with just over 90 per cent certainty – that sea levels are “unmistakably” rising. How much of a problem that will be is a moot point.

Taking its lead from Sir Michael Pitt’s review of the 2007 floods, Facing up to rising sea levels conducts a thought-experiment about two high flood-risk cities: Kingston-upon-Hull and Portsmouth. Undoubtedly, there are real issues to be addressed, but this report adds nothing to the debate, except as a self-fulfilling driver for more consultation reports on the same topic. Using scenario planning, it asks whether we should retreat, defend or attack.

“Retreat” implies allowing nature to take its course, whereby the “severe risk of a flooded future” could be turned “a ‘destination-making’ intervention?” “Defence” reflects a more traditional tidal barrier strategy but one that, for Building Futures, incorporates “performing arts spaces and other art venues” in the sea wall. And the “attack” theme suggests, inter alia, appropriating decommissioned oil platforms or building “smaller houseboat communities”?

Actually, the report acknowledges that Hull’s recent floods were caused not by breached flood defenses but because the “city’s drainage infrastructure was unable to cope.” On that basis, it could be argued that the headlong rush towards Sustainable Urban Drainage (retaining surface water in situ) while shying away from effective mains infrastructure, is an accident waiting to happen.

It’s worth remembering what happens without major infrastructure. In 1953, 300 people in the UK were killed by a 2.7 metre high tidal surge that swept around the east coast of Britain. (Hull is at 2 – 4 metres above sea-level). The flood was even more devastating in the Netherlands. Reaching a maximum height of 5.6 metres above mean sea level, it killed 1835 people and created 500,000 refugees. In the UK, the disaster forced the government to initiate a project of coastal upgrades, but with much of its land below sea-level, Holland’s long-term flood defence ambitions were of central important to its existence. As a result, its Deltawerken barrier project took 45 years to complete.

Dutch long-termism is instructive; the Atlas is an examination of the historic ambition of the Netherlanders to employ engineering solutions and structural planning on a vast scale and timeframe in order to transform nature. Building Futures want to accommodate to nature. Which one is the folly?

This review was first published in the  Blueprint,  February 2010

“Atlas of the New Dutch Water Defence Line”; 010 Publishers, 2009.  224pp   Buy this book on Amazon UK

“Facing up to rising sea levels”, Building Futures, RIBA.  Download the report here