Designing future resilience
Jan 13th 2016
We closed 2015 with an item on the deluge that swept across the UK in December and the statement by the Environment Agency’s Deputy CEO that a complete rethink of the UK’s flood defences is required. We also looked briefly at some of the innovations and improvements that have been adopted in the UK with regard to flood warning systems and flood defence technology. We concluded that amphibious homes seem an obvious topic to consider when designing future resilience and flood protection measures. In fact, according to its designers, the UK’s first amphibious home is nearing completion.
The UK’s first amphibious home
The UK’s first amphibious home was granted planning permission in 2012. The house is designed by the London-based Baca Architects, specialists in waterfront architecture and flood-resilient developments. It is situated on an island in a stretch of the River Thames as it passes through Marlow, Buckinghamshire, on a site designated as Flood Zone 3b and a Conservation Area, and located just 10 metres from the edge of the river. The architects explain the concept as follows: “An amphibious house is a building that rests on the ground but, whenever a flood occurs, the entire building rises up in its dock where it floats, buoyed by the flood water. The house itself sits in the ground and the floating base is almost invisible from the outside. The ground floor of the house is raised above the ground by less than a metre rather than by almost two metres as would be required were it not amphibious.”
In terms of design, Baca says that the house will replace a dilapidated bungalow with a contemporary family home, “designed to respond to the uncertainties of future climate change. The upper part of the house will be a highly insulated lightweight timber construction. This will rest on the concrete hull creating a ‘free-floating pontoon.’ The whole house will be set between four ‘dolphins,’ which are permanent vertical guideposts. These are expressed on the outside of the building, rising to the height of the eaves.”
In terms of how the system works, the architects explain that there’s a hydrological link between the groundwater on the island and the River Thames; essentially, as the river rises, so will the groundwater. The dock fills gradually from the ground, gently raising the building as the river level rises. When the water is just below ground level, the house becomes buoyant. The house is designed to withstand a 1 in 100 year flood event by rising up to 2.7 metres. However, the guide posts extend almost 4 metres above ground level so that in the event of an even bigger flood the house would still be retained between the posts. The pipes in the house are flexible and are designed to extend up to 3 metres, “allowing all of the services to remain clean and operational during any flood event and crucially to allow the occupants to return to the property immediately after a flood, maximising the continuity of their daily lives.”
The architects also explain how the system will be maintained via a flotation test, should there be a period when no flooding occurs to activate it: “Every five years the dock will be pumped full of water to repeat the flotation test when the house will rise up to 50 cm to test the integrity and free movement, before the water is slowly released and the building allowed to touch down again.
In summary, the architects describe the advantages of amphibious construction: “Amphibious construction brings together standard components from the construction and marine industries to create an intelligent solution to flooding. It is slightly more expensive than other solutions due to the two foundation systems (dock and hull), but comparable to typical basement construction. However, it is ideally suited to areas of high flood-risk or where there is uncertainty in future flood levels and in historical or sensitive landscape settings where other solutions would be unacceptable.”
Living on water: The Netherlands
Amphibious construction has been pioneered in the Netherlands, where much of the land lies below sea level. In 2005, the construction company Dura Vermeer built a number of amphibious homes as well as several floating homes on a stretch of the River Maas as it flows through the village of Maasbommel, about 60 miles from Amsterdam. Writing for Inhabitat, Evelyn Lee says each of the 26 brightly colored homes is built on a hollow concrete cube base that’s anchored to the land by a single vertical pile. All utilities, including electricity and water, are brought into the house through flexible pipes that allow each house to adapt to a 13ft rise in the surrounding groundwater.
A major pioneer of water-based architecture is the designer Koen Olthuis, whose company Waterstudio (based in the Netherlands) have designed amphibious villas; a floating quarter in Utrecht; Citadel, “the first floating apartment complex;” New Water, Westland, “the first living area on an open water storage;” a floating mosque for the UAE; and “China’s first floating, low carbon, eco-friendly healthy living center.” Koen Olthuis promotes the concept of ‘floating dynamic cities‘ as the way forward in adapting to climate change and rising sea levels.
Living on water: The UK
In some parts of the world, people have been living on water for hundreds of years. Homes on stilts for instance are a common feature in countries such as India, Thailand and Burma, where flooding has been a regular and seasonal occurrence. In the UK, there are a number of homes alongside Taggs Island that are attached to piles driven into the bed of the River Thames. However, the amphibious home represent a new concept for the UK, and one that’s been driven by the recognition that we need to adapt to climate change, with the likelihood of more frequent and more extreme weather patterns. ‘Floating dynamic cities’ may be a long way off, but plans for floating villages are currently in place for both Glasgow and London.
Living on water: A floating village for Glasgow
The plans for a floating village for Glasgow were unveiled in January 2011 as part of a regeneration plan for the waterfront of Glasgow’s River Clyde. BBC News reported that the proposals would see a £30m floating leisure village at Canting Basin on the south bank of the Clyde, with a mix of office buildings, studio flats and town houses with their own private moorings. Under the proposals, Canting Basin would be transformed into a “spectacular floating community with shops, offices, houses, restaurants, a marina and a roof-top concert arena.” The economic development agency Scottish Enterprise selected the company Floating Concepts as the preferred bidder to take the project forward. Baca Architects – who also designed the UK’s first amphibious home – is one of the companies who designed the proposal, the other being ZM Architecture, based in Glasgow. For the latest news of the development, see “Clyde Waterfront Regeneration”.
Living on water: A floating village for London
Two years after the Glasgow plans were unveiled, London Mayor Boris Johnson announced plans to transform the Royal Victoria Dock on the River Thames. The plans include floating homes, hotels, restaurants and leisure facilities covering a 15-acre area of the river. The Mayor said the floating village would be the largest floating development in the UK, the Glasgow development covering 12 acres. BBC News quoted the Mayor of Newham, Sir Robin Wales, who said: “London is moving eastwards and the Royal Docks offer an investment opportunity in scale unmatched anywhere in Europe. This exciting development is a pivotal part of their reanimation.” 
In July 2014, the Greater London Authority issued a press release to announce that the plans for a floating village on the River Thames had moved a step closer with the appointment of the development company who would take the proposal forward. A consortium of three organisations won the competition for the role, comprising the construction firm Carillion, the regeneration funding body Igloo, and Genesis Housing Association. The architects who designed the proposal are dRMM, led by Professor Alex de Rijke.
On the design, the press release said: “The winning consortium’s scheme includes a custom-build approach for each of the 50 residential homes, enabling prospective occupiers to be part of the design process of their homes, and a blue water square, framed by a market square and a floating corniche. There will also be a large multi-purpose events space and a mix of non-residential uses including restaurants, cafes, shops and leisure and office space. Plans for additional facilities, such as a floating Lido and an ice rink, were also proposed as part of the bid. The scheme takes inspiration from the tried and tested floating homes at Ijberg and have been assisted by Dutch floating structures experts Mark van Ommen of Floatbase and Ton van Namen of Monteflore who have already delivered exemplar schemes of over 300 floating structures.”
In terms of construction, the press release said that the proposal is “100% floating with the walkways, residential and non-residential units anchored in place using a series of piles located within the dock and connected to the dock by bridges. The construction of the homes including the bases will be carried out off-site and then transported by water to the site.”
John Carleton from Genesis Housing Association said that, because of their involvement in the bidding process, they had been able to secure a higher allocation of affordable housing within the scheme, “which chimes closely with our mission to deliver diverse, mixed tenure developments in London and the South-East.”
The Mayor’s plans were said to be “part of his ongoing drive to transform London’s Royal Docks bringing jobs, commercial space and homes back to the capital’s waterways.”
 “London is moving eastwards”: In November last year, the Mayor launched his plans for a ‘City in the East,’ which included plans to build 200,000 homes on brownfield sites in East London. See our news item “London Mayor launches ‘City in the East’ master plan” for more information.
Photograph: Houseboat moored by Tagg’s Island © Copyright Stefan Czapski and licensed for reuse under this Creative Commons Licence. “The houseboats along this stretch of the River Thames range from the makeshift and basic through to the really stylish – like this one, moored just across the river from the boathouse of Molesey Boat Club.” The island itself is uninhabited.