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edition 3 (208)
March 2016

Water world

Dutch visionary on why floating cities are the way forward in an era of climate change

Rafał Ostrowski

Water world
Koen Olthuis

For Koen Olthuis, who has made a name for himself designing floating structures, the advantages of building houses on water seem endless. If we eventually embrace this concept, as he claims we will have to, our cities will never be the same again

Rafał Ostrowski, Eurobuild CEE: In 2007 you were recognised as one ofmost influential people inthe world. In anannual opinion poll ofthe readers ofTime magazine, you were ranked 122 globally and its quite unusual for an architect to appear at all on such alist. Doyou feel like youre soinfluential?

Koen Olthuis, architect and founder ofDutch architectural firm Waterstudio: To be honest, when we received this recognition in 2007 it was a bit awkward for me. I thought that we had only just started out and we just had this vision – and that was basically all. Today we understand the systems of cities much better and we are also seeing that our vision has become much more realistic. We are being invited by governments and authorities all over the world to share this vision.

What is your vision?

Well, the cities today are completely static. What you’ve once built, you cannot easily change – and I think that if you live in a dynamic society you should also create dynamic cities and be ready for any possible changes that could occur in the next twenty years. So there should be some kind of flexibility, a short response time to such problems and a different way of thinking. And I think that by using water, by pushing our cities towards the water, you can create this new flexibility, and you also create new space and new security. That’s the message that we are trying to spell out to the world.

How would this be possible?

Water gives us enormous flexibility because structures located on water can be brought in and taken away. If you are unsure whether what you are building is needed for the next 100 years, you can build it on water, because then you can remove it or replace it with something else. In this sense these buildings can be dynamic. They are also more secure, because everyone knows that when floods come they will just go up and down on the water. So that means we can also build in locations much more threatened by water than those we use now. For example, Bangkok, Tokyo, New York, Shanghai – all these cities will have to rethink how they want to develop their waterfronts.

Doyou think inthe next two or three centuries people will prefer to build cities on the water instead ofthe land?

No, I didn’t say that. But I think we should add water to our cities. A hundred years ago we only had horizontal cities, but then Elisha Otis invented the elevator and it was possible to build vertical cities instead. Then we became able use the space better. So that created a completely new way of thinking. Well, the same is true now. We are moving from traditional land-based cities to those that employ water. So, to go back to your question: do I think that in a hundred years everybody will be living in floating cities? No. Do I believe that every waterfront city will start to use water for expansion? Yes, absolutely. In the next hundred years, maybe 5–10 pct of these cities will be built over the water’s surface. So there will be a significant shift to hybrid cities from land based ones.

On your web page Ive seen the concept for astadium built on water and that could be towed from one place to another. What is the idea behind this?

The reason for creating this concept was that there are so many public buildings or functions that can only be used for a very short time, while the investment in these functions are quite high. This includes Olympic stadiums and football championships arenas, which very often are not used so much after the event is over. And so many countries can’t afford to host such football tournaments. If these countries could just lease or rent these kind of functions for a year or two, afterwards sending them back, then the entire financial model of events would be transformed.

Who would invest inthe development ofsuch leasable stadiums?

If you look at Saudi Arabia, Qatar or Norway, there is so much money in those countries and this can’t just be spent in the country of origin. So what investors do is to buy property all over the world. But what they could do instead of buying static property, would be to start building these kind of floating facilities in order to lease them out. So you get a world full of global mobile assets which cities can lease for all kinds of functions. Because this doesn’t have to be only stadiums – it could also be housing, universities, parks, boulevards, swimming pools or cultural centres. All kinds of large-scale floating facilities.

In some languages, the word for real estate, such as immobilier inFrench, implies that the property cannot be moved around. This would break that whole model, wouldnt you say so?

Yes, absolutely. We can make something that is in our minds so static, such as a house, but that can be moved to another location. You don’t have to move it, but you can move it and that can happen once or twice during its lifespan; or if you so choose you can relocate it according to the season. It’s easy to imagine that in the winter you might want to live in a completely different city than in the summer. In the winter you might want to have a very compact, warm, dense city, while in the summer you could have it much more open and friendly – an outgoing kind of city. You can design parks or houses that can be moved or rotated seasonally.

Returning to the idea offloating stadiums. Isuppose it could be ahuge technical challenge to build such large structures on the water. Am Iright?

Well, no. In fact, it isn’t. People think that it must be very difficult to build such structures and transport them from one location to another, but we don’t even have to develop new technology to achieve this. If you see how the oil companies move their huge oil rigs from Rotterdam to Nigeria and back for maintenance to Rotterdam, they are all transported on enormous transport ships of 50 by 100m. You could also imagine that a floating stadium is nothing else than four parts the size of an oil rig being transported and then reconnected to each other. So the technology is already there. It is just in our mind-set that it is not possible. Nevertheless, it is possible to do this – we just have to employ technology from other fields.

How far could you move such astadium bywater?

All around the world, as long as there is water to move it across. But this is not about the technology, it’s more about the feasibility. We are working on floating islands that are being made in the Netherlands and transported to Dubai. To transport one island – and these islands are a nice size, about 20 by 50 metres – costs about USD 800,000. So it is quite expensive.

Could you explain simply how it is possible to construct abuilding on the water? Whats the key to doing this?

There’s no special trick involved. Floating houses have been constructed in the Netherlands for the last hundred years. For this a floating foundation is always necessary. This is a kind of concrete box. Rather like a huge shoe box on top of which the house is positioned. It is similar to a cellar. And it floats: the same way that a steel ship floats, a concrete ship will also float. And if you are building the largest floating structures, up to 200m in length, you can use a combination of concrete blocks and polystyrene blocks. The polystyrene provides buoyancy, while the concrete gives it stability. So in this way we can create large floating foundations, on which you can build the streets, houses and greenery that form the urban components of a city.

Arent people afraid that such concrete foundations will become waterlogged and simply sink?

Yes. People are afraid of this; but as I said, we have had these floating buildings in the Netherlands for a hundred years – and the only time there’s been a problem was on one occasion when a floating house sank after 150 people climbed onto the roof during the celebrations for Holland winning the European Football Championships in 1988. But in general, a concrete box filled with foam can’t sink, because if there EPS in it, there can’t be water in it, so they are unsinkable. Therefore it is technically impossible for the biggest structures to sink.

How durable are such houses?

The structures that we build today have a lifespan of 100 years. So they are guaranteed not to sink during that time. And then houses are built upon it, which have just the same durability as normal house. When it comes to sustainability, we try to be as green as possible. We use solar panels and also water to cool the buildings. In Dubai, for example, the water is 27 degrees, but outside it is 50 degrees. So if you can pump that water through your walls cooling down the building with sea water, you save energy, because the sea is such a huge buffer of energy.

How doyou prevent floating houses from rocking?

Well, this has to be done. It’s important to know that there is not one type of water and, of course, it is much more difficult to make a house stable on the ocean than on a small lake. So when designing a project, we first look at what waves do, what the worst climate change scenario is for the next 100 years that could affect the weather, and then we start designing it. We factor in all that data to predict the kind of movement we should expect. Then we employ all kinds of tools to stabilise the building. So in the end you won’t even feel that the house is on water. They have just the same comfort as a normal house. This is the reason why people want to live in floating houses. If they felt sea-sick or felt the house move, the price of it would drop dramatically.

But water is avery dangerous element and inthe ocean youhave huge waves. There must be some limits to this technology.

There are financial limits. On the ocean you have to build oil rigs and oil ships to pump oil out of the ocean. And if you look at the weather conditions in Mexico, those platforms cost millions to build, so you will never use that technology to build just one house on the top of them. Technically it is possible, but in reality you are always looking for an easier place for building, such as a lake or canal, or a river. Seas and oceans are not the number one choice. In Dubai we are currently working on ‘The World’ project. For this we have built floating islands behind large breakwaters, which reduces the wave activity. And then it’s easy. It is also possible to develop buildings on moving water, such as rivers, but you have to anchor them well. A little added technology is needed. And also the bigger the development, the easier it gets. Because a small floating house, just like a small boat, will react more to the waves or to the wind than a very large scale floating development (of, for example, 100 by 100 metres). This also has to do with where its centre of gravity is located.

Is humidity achallenge? Nobody would like to live inadamp house.

We are asked this question quite a lot, so we invite all these people to see the floating houses in the Netherlands. When they go into the underwater cellars, they can see that they are completely dry. There’s no difference: it’s just a normal cellar. Also, in the Netherlands, which is such a wet country, the cellar of a normal land-based house is completely surrounded by groundwater. This is not so different from having a floating foundation. So the humidity is not a problem. Buildings on top of a floating foundation are no different in this regard to any waterfront houses. They both experience the same humidity. Only the foundation is different.

Moving to the CEE region Iknow that you are designing afloating house for aprivate client inKyiv. Ihave also heard about aproject inGeorgia. You could say that this is not such apopular concept inour region. Why?

The most important thing is to make people see that it works. They are afraid of what it is, how it is, and are afraid of the water. So we tell them that you don’t have to be afraid. If somebody feels threatened by water, he should consider living on it instead of next to it. Because being on top of it you move with the water instead of being flooded by it. So it is a matter of changing those attitudes and this also takes time. But we are now becoming more effective in developing this kind of technology. This is the reason that only now some projects are really taking off. And it will take another ten years before more cities start to embrace it, I think. But once we go through a kind of critical mass, you will see that many will be keen to back this idea. What we are seeing in some cities, because of climate change, is that the so-called grey zones on the edges of rivers, which are sometimes wet and sometimes dry, are gradually expanding. And this means that there is less space available for those cities to build on. So if you can build floating structures, you can use the space more effectively. And you will probably see that all the old or redundant harbours that many cities have will be the first to be transformed into floating neighbourhoods. It will be easy to use floating houses and floating facilities to develop flexible and safe neighbourhoods.

Is it very expensive to build on water?

No. But, the economy of scale is a very important factor. If you want to build 100 houses on water, the price is not that much different to building them on land. If you want to build one floating pillar, then it is probably about 10–15 pct more expensive than a house on land. And this is all because of the mooring and the foundation.

Who are your most common clients? Are they private individuals, developers or public investors?

I think governments love this idea, because by changing water into development area, they can make lot of money and benefit from this sort of development. Developers like it because they can buy water cheaper than land and are still allowed to build in the centre of cities. There are also clients who want resorts and leisure facilities to be built on the water too. So we cannot say there is a typical
client. They can range from one individual up to the government level.

What are your predictions for the future? How will this market and sector evolve?

What I see is that architects today understand much better what their role is. Ten or fifteen years ago, young architects thought they should be designing fantastical, iconic buildings. Today the people who come into our office are not interested in such schemes. They want to change the world, to make it a better place. So I think this trend will continue to pick up steam. I think all these people will be part of the climate change generation. And this generation has emerged to make our cities perform better. Now I think that water is part of the solution for making cities perform better. I expect that within fifty years it will be as normal to build houses on water as it is now to build high-rise buildings on land. So this will just become another way to use space in the city. But I also think that as a result we will be able to build projects in just half a year or within three or four months, instead of waiting five years before new buildings appear. So it will be thanks to using the water that our cities will become much brighter, safer, more flexible places – and much more fun to be in.

What will these future cities look like?

I think in the end a floating city will not look that different to our contemporary cities. I don’t think that people will want to live in a city that is very futuristic or completely based on water. They just want to have a city that is fantastic to live in, that has a very good atmosphere, that is not expensive to live in and that performs well. So the difference will mainly be to do with the fact that underneath these cities different technology will be used. But on the top of this it will all be rather similar: high-rise buildings, greenery, parks, streets, cars and so on.

Floating Dutchman

Koen Olthuis is a Dutch architect and the founder of Rijswijk-based company Waterstudio.NL, which specialises in floating structure designs. He studied architecture and industrial design at the Delft University of Technology. Among his innovations are City Apps – floating urban components that add certain functions to the existing static grid of a city. Using existing urban water as building space creates a new density, offering global opportunities for cities to respond flexibly to climate change and urbanisation. The first city in which this vision is being developed is Westland, near The Hague. This project involves floating social housing, floating islands and floating apartment buildings. In 2010, the government of the Maldives agreed to develop a floating city, floating islands, floating golf courses, floating hotels and a floating conference centre in a joint venture, as a solution to the problems caused by rising sea levels and also to encourage social and economic advancement.

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