Imagine a flood without sandbags, berms, pumps or panic — one that did little or no damage to waterfront homes.
That’s the vision of University of Waterloo professor Elizabeth English, an architect who has pioneered research into the use of buoyant foundations and floating homes.
The foundations allow a home to rise straight up on guideposts when flood water moves in, float above trouble, and settle back into place when the water recedes.
“It’s exactly like putting a floating dock under your house,” explains English, an expert in amphibious architecture and the founder of the Buoyant Foundation Project , a non-profit dedicated to advancing the flood mitigation strategy in places such as Louisiana, Vietnam, Bangladesh, Nicaragua and Jamaica.
English is now working with the National Research Council (NRC) to test whether the strategy could work in Canadian flood zones.
The research is part of the NRC’s $42-million Climate Resilient Buildings and Core Public Infrastructure Initiative, a program designed to help communities and builders adapt to the challenges wrought by extreme weather events.
With a four-year, $500,000 NRC grant, English is developing two prototypes for use in Canada — one a cottage retrofit and the other a new home build.
The prototypes are being designed for First Nations communities that experience frequent spring flooding. The principal challenge, English says, is finding materials that will survive Canada’s extreme freeze-thaw cycle, and identifying places where the strategy can succeed.
“This is not an appropriate solution for every situation,” she notes. “It’s not a one-size-fits all kind of thing.”
Buoyant foundations can only be used on homes without basements, and they’ve not yet been engineered to withstand the destructive force of fast-flowing rivers, ice floes or big waves. But advances are being made, English says, and existing models could be used in protected bays along the Ottawa River.
“It’s just so simple. That’s why I like it,” English says. “It works with nature; it’s not challenging nature. It’s not saying we have to stop the flood or move the water.
“It says, ‘The water is going to come and we’re going to accommodate it.’ The water becomes your friend rather than your foe: It’s the water that lifts the house and carries it up to safety.”
To retrofit a home , it first has to be raised. A structural subframe is built with cross beams and buoyant blocks. The floats can be made of expanded polystyrene (EPS) — commonly used under floating docks — or plastic barrels.
The subframe and home have to be affixed to vertical guideposts sunk into the ground. The posts can be static or can telescope out of the ground in the event of a flood, allowing the house to rise and fall without floating away from its foundation.
The homes also use coiled “umbilical lines” for water supply and hydro, and breakaway connections for gas and sewer lines.
The advantage of the design is that homes retain much of their original appearance until flood waters arrive. Enough buoyancy blocks can be added beneath a home to lift almost anything out of the water. The real limitation is stability: Keeping the centre of gravity of a floating home low enough to prevent it from tipping over in wind and waves.
“Low and wide is good,” says English.
Amphibious design is not new. Floating communities can be found throughout the Mekong Delta, and one of the largest slums in Africa — Makoko — is built on stilts and floating barrels in Lagos, Nigeria. The Uro people have been building floating communities on Peru’s Lake Titicaca for centuries. Even in Louisiana, residents of Old River Landing have been using amphibious design for more than 40 years to limit damage from Mississippi River floods.
Still, the need to improve amphibious design has never been more pressing.
In the past two decades, the world’s 10 worst floods have displaced more than one billion people while causing an estimated US$165 billion in damage. And although flooding is complicated by the way people divert, collect and store water, most climate scientists believe it will only get worse as Earth’s atmosphere warms. Simply put, a warmer atmosphere can hold more moisture, which results in more snow, rain and havoc.
Born and raised in New Jersey, English began to think about floating homes after Hurricane Katrina inundated low-lying neighbourhoods in New Orleans.
At the time, in August 2005, she was a professor at Louisiana State University’s Hurricane Center where she studied the effect of wind on tall buildings and how to protect them against hurricane damage. (She holds an undergraduate degree in architecture from Princeton University, a master’s degree in civil engineering from the Massachusetts Institute of Technology and a PhD in architectural theory from the University of Pennsylvania.)
English was appalled when she discovered that the Federal Emergency Management Agency’s answer to flooding was to raise homes on stilts: It put them one-storey above the ground and made them more susceptible to wind damage.
“I was just horrified at what happened to New Orleans, and the inadequacy of FEMA’s response,” she says. “I figured, if someone who was an architect and engineer working at a hurricane centre couldn’t come up with a better solution than putting houses up on stilts, then who could?”
English went in search of more elegant alternatives, and discovered floating homes. After founding the Buoyant Foundation Project, English sought to improve on existing designs. Many people laughed when English told them what she was working on, but the first full-scale prototype floated to the surface of a flood tank on the L.S.U. campus in the summer of 2007.
“That was a religious experience for me,” she says.
Engineered to be used in places like New Orleans’ impoverished Ninth Ward, the initial design was simple and inexpensive: It cost as little as $10 a square foot to install. More advanced models cost $20 — $25 per square foot.
In late 2007, English accepted a job at the University of Waterloo, where she has sought to broaden the application of buoyant foundations. Amphibious architecture is now the subject of an annual, international conference.
“I want it to come out of the clouds and be accessible to everyone,” says English. “There are an awful lot of people who need this technology.”
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