worried about rising sea levels? Go to the Netherlands — they have lots of experience with these things
Paul Whelan, illustration: New New York by Hugo Arriojas
According to a pair of studies published in the journal Science, global warming has already committed our planet to rising sea-levels. Jonathan Overpeck, an earth scientist at the University of Arizona in Tucson who co-authored both studies, says that the sea level will rise at rates of up to a metre per one hundred years – and it could go faster.
Humans are vulnerable because we build most of our cities in low coastal areas. The recent example of New Orleans and the ongoing struggle between the Netherlands and the sea are reminders of our future reality. We know that the water is rising, so what can we do? The obvious answer is to reduce our dependence on carbon ... but humans are catastrophically bad at taking preventative actions. Inevitably we will have to adapt to global warming and all its consequences, including higher sea levels.
However, there is a continuum of available responses ranging from holding back the water, making or buildings float, or simply doing nothing.
Beavering Away
If we decide to fight the seas and hold the water back, the Netherlands offers planning, engineering and political lessons Their extensive systems of dykes, dams and drainage strategies are designed to keep land below sea level dry. Rising sea levels threaten the entire country.
Recently a Dutch landscape firm, H+N+S, have proposed a new response to the triple threat of rising sea levels, subsiding land and increasing rains. To dampen the impact of ever-increasing storm surges, H+N+S propose selectively channelling the water behind the defences. H+N+S advocate catchment systems for fresh and salt water and reservoirs for excess rainfall. This strategy will require relinquishing land so strenuously won from the sea. The landscape will change from traditional farmland with water channels and ditches to one of raised lakes and reservoirs – a kind of non-sensical contour map. However, it could be the only way the Netherlands can save its country.
Regardless of the engineering and planning, the Dutch rely on a highly centralised government to construct and maintain their sea defences. Their system of participatory and centralised democracy is a political anomaly and I fully expect that fighting the sea would more likely result in less-friendly autocratic government.
Floating
Happily, buildings can float. there are two models for floating foundations. the Canadian model is based on the diving raft with concrete poured around polystyrene. These structures are unsinkable, but tend to be less stable for non-square geometries. Not surprisingly, the Dutch have been experimenting with floating buildings. Based on the river barge, Dutch technology consists of a floating concrete container in which the lower level becomes an underwater basement. Waterstudio Architects of the Netherlands have designed floating houses and are currently developing a 25-storey floating office tower and courtyard housing prototypes.
To date, floating buildings depend on nearby dry land for services or are anchored with mooring poles that also provide an umbilical connection for services. Without sea defences, floating buildings will be extremely vulnerable to increasingly violent storms, except where large expanses of newly inundated lagoons could provide a storm-damping environment in flat low-lying areas. Floating buildings could be effective in marshy delta areas that are already threatened by rising waters.
Do Nothing Romanticism
Doing nothing may ultimately be the most romantically compelling response to rising sea levels. Venice, a city that accepts its regular inundations, may offer the most clues for the benign-neglect approach. As Venice slowly disappears, many other cities could take its place as a magical tourist destination. Imagine gondoliering through a New York transformed into a city of canals and skyscrapers. However, a deliriously wet New York will ultimately require serious design to ensure the right level of submersion. At the very least, infrastructure such as the subways, potable water, power and sewage would have to be re-engineered.
Saving our sinking sea-level cities will be an expensive undertaking. The capital needed to re-engineer an entire city will be scarce as businesses move away to drier and higher ground. Whole districts of the city will elegantly decay as the water laps at their second floor windows. We live in an era where financial markets dictate settlement form. As in Venice, it is quite likely that at some tipping point, the rich will abandon the coasts for safer inland settlements, leaving the poor to cope with their deteriorating coastal cities.
In any built response to rising sea levels, infrastructure and its maintenance will be a significant challenge. What we humans lack in intelligence we sometimes compensate for by cleverness. Perhaps we will be making floating cities anchored to the atlantan ruins of our submerged cities. Maybe our future will be a combination of Futurism fantasy and Disney picturesque.
Whelan, Paul. 'Soggy Bottom Architecture' On Site review, no. 17 Spring/Summer 2007
©Paul Whelan, Hugo Arriojas and On Site review
10 February 2009
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