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Holding back the floods

By Scholastic
Science World


After one of the worst hurricane seasons on record, what can the U.S. learn from countries With centuries of experience managing floods?

ESSENTIAL QUESTION: Why might collaboration be important when it comes to solving large engineering problems?

Last August, Hurricane Harvey barreled into the Texas coast. In just a few days, the storm dumped more than 1.2 meters (4 feet) of rain On Houston, America’s fourth inost-populous city, and surrounding areas. It set a new record for rainfall from a single storm and led to widespread flooding. Dozens of people died. Tens of thousands had to evacuate, with many still unable to return to their flood-damaged homes. Like Hurricane Sandy, which hit the Northeast five years earlier, and Hurricane Katrina, which devastated the Gulf Coast in 2005, Harvey demonstrated how vulnerabble U.S. coastal communities are to flooding. More than  120 million Americans—nearly 40 percent – live in a coastal county. And that, population is growing rapidly.

Scientists believe climate change could bring even more intense flooding to the U.S. Warming temperatures and shifting global climate patterns are not only raising sea levels but could also potentially cause more extreme storms. As a result., U.S. coastal communities are looking for ways to prepare for the future (see Fighting Poods Worldwide, p. 17) They’re gathering data locally and collaborating with experts around the world to identify the best strategies to keep people and essential facilities above water.

Perhaps no country on Earth has as much experience protecting against floods as the Netherlands. About a third of the small European nation’s land is below sea level—and much of that area would be underwater if not for centuries of expert engineering. “Flood protection is a huge part of our history and culture,” says Harold van Waveren, a senior adviser for the Dutch government’s flood-prevention agency. “Without it, our country wouldn’t exist.” Van Waveren lives near Amsterdam at a depth of 5 m (16 ft) below sea level in a polder—an area surrounded by walls, called dikes, that keep water out. The country has nearly 3,500 polders, protected by 40,000 kilometers (25,000 miles) of dikes and dams. Flood protections have continued to evolve since Dutch farmers built the first dikes a thousand years ago. A major storm in 1953 that flooded the southwest Netherlands and killed 1,800 people motivated the country to build the massive Delta Works. This project constructed new barriers and dams to protect against storm surges—increases in sea level due to wind and air pressure changes during storms. The project also included channels called sluices, which drain excess water during floods. The crown jewel of the Delta Works is the Maeslantkering (MANS-lau_mt-keh-ring), a giant barrier completed in 1997 that protects Rotterdam, one of the world’s busiest ports, from the sea. Ships must enter and exit the port, so building a permanent barrier that blocked the sea wouldn’t work. Instead, the government decided on a huge gate that remains open most of the time and swings shut during storms (see The Netherlands’ Giant Sea Gates, p. 15).

The Maeslantkering successfully held back the sea during a 2007 storm. But storm surges aren’t the Netherlands’ only flood threats: In 1995, dikes surrounding the narrow Waal River nearly failed during heavy rains, threatening the city of Nijmegen (NYE-may-ken). Some 200,000 people evacuated. “That led to a big change in our strategy,” says van Waveren. “Until then, we thought we could manage nature and have it do as we wanted. But we realized nature is sometimes stronger than we are. We had to stop fighting it and find ways to work with it.” Current flood protection strategies in the Netherlands focus on allowing nature to safely take its course during floods. Workers are restoring and protecting coastal lands like beaches, marshes, and dunes, which provide natural buffers against storms. At more than 30 sites around the country, engineers are also creating additional places where water can go. The city of Nijmegen is part of this program, which is called Room for the River. There, workers recently built an extra channel so river water can flow around the city when the level rises. Low-lying areas are being turned into parks, gardens, sports fields, and other amenities that can act as reservoirs for floodwaters in emergencies without harming people or infrastructure. Builders are also moving dikes farther from the river to create additional space for floodwaters.

On the coast of Texas, the U.S. Army Corps of Engineers (USACE) is investigating similar plans to combat storm surges. “The biggest element we’re considering is a large gate structure in the Houston-Galveston area that could be closed if a storm is coming,” says Sharon Tirpak, who is overseeing the study. One possible design resembles the Maeslantkering. “If it’s chosen, it would be one of the largest structures in the world,” she says. For storms like Harvey that dump massive amounts of rain, a sea gate would do little to stop flooding. So the Texas study is also evaluating how natural features like wetlands could help absorb heavy rains. The fact that so much of Houston is covered in concrete is one reason it flooded so badly, says Henk Ovink, the Dutch special envoy for water affairs. His job is to share Dutch expertise in flood management with countries around the world. Restoring native prairies and wetlands, which can soak up water, could help protect Texas and other areas against future floods. A team from USACE recently visited the Netherlands to tour Dutch coastal defenses. And Dutch flood engineers came to the U.S. to compare methods for evaluating the stability of levees—our version of dikes. Ovink says the challenges ahead represent an opportunity for coastal communities to come together to innovate. “In the form of rising seas and storms, water gives a tangible meaning to climate change that we have to prepare for,” he says. “But we can do this. It doesn’t have to be something we fear.” —Jennifer Barone

Besides the Netherlands, other countries and cities around the world are developing innovative approaches to prevent and adapt to floods. Here are a few.

The city is building “green alleys” made with permeable materials like special kinds of concrete and paving stones that allow water to pass through or between them instead of collecting on the surface.

FUTURE CITY: Gardens and trees line a public space. )

STORM MODE: Soil and channels help absorb and divert water.

CHINA is constructing 16 “sponge cities” that incorporate wetlands and rooftops covered with plants. The plants will soak up water, and the wetlands will store water during storms.

A new project will bring five floating shipping containers—including essential facilities like a floating classroom and a kitchen—to a flood-prone neighborhood.

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Thailand tests floating homes in region grappling with floods

By Alisa Tang
Thomson Reuters Foundation



In this picture provided by Site-Specific Co Ltd, the 2.8 million baht ($86,000) amphibious house, designed and built by the architecture firm Site-Specific Co Ltd for Thailand’s National Housing Authority (NHA) rises up 85cm after architects and NHA staff fill a manmade test hole underneath the house with water during a trial run in Ban Sang village of Ayutthaya province September 7, 2013. REUTERS/Site-Specific Co Ltd/Handout via Reuters

AYUTTHAYA, Thailand (Thomson Reuters Foundation) – Nestled among hundreds of identical white and brown two-storey homes crammed in this neighborhood for factory workers is a house with a trick – one not immediately apparent from its green-painted drywall and grey shade panels.

Hidden under the house and its wraparound porch are steel pontoons filled with Styrofoam. These can lift the structure three meters off the ground if this area, two hours north of Bangkok, floods as it did in 2011 when two-thirds of the country was inundated, affecting a fifth of its 67 million people.

The 2.8 million baht ($86,000) amphibious house in Ban Sang village is one way architects, developers and governments around the world are brainstorming solutions as climate change brews storms, floods and rising sea levels that threaten communities in low-lying coastal cities.

“We can try to build walls to keep the water out, but that might not be a sustainable permanent solution,” said architect Chuta Sinthuphan of Site-Specific Co. Ltd, the firm that designed and built the house for Thailand’s National Housing Authority.

“It’s better not to fight nature, but to work with nature, and amphibious architecture is one answer,” said Chuta, who is organizing the first international conference on amphibious architecture in Bangkok in late August.

Asia is the region most affected by disasters, with 714,000 deaths from natural disasters between 2004 and 2013 – more than triple the previous decade – and economic losses topping $560 billion, according to the United Nations.

Some 2.1 billion people live in the region’s fast-growing cities and towns, and many of these urban areas are located in vulnerable low-lying coastal areas and river deltas, with the poorest and most marginalized communities often waterlogged year-round.

For Thailand, which endures annual floods during its monsoon season, the worsening flood risks became clear in 2011 as panicked Bangkok residents rushed to sandbag and build retaining walls to keep their homes from flooding.

Vast parts of the capital – which is normally protected from the seasonal floods – were hit, as were factories at enormous industrial estates in nearby provinces such as Ayutthaya. Damage and losses reached $50 billion, according to the World Bank.

And the situation is worsening. A 2013 World Bank-OECD study forecast average global flood losses multiplying from $6 billion per year in 2005 to $52 billion a year by 2050.


In Thailand, as across the region, more and more construction projects are returning to using traditional structures to deal with floods, such as stilts and buildings on barges or rafts.

Bangkok is now taking bids for the construction of a 300-bed hospital for the elderly that will be built four meters above the ground, supported by a structure set on flood-prone land near shrimp and sea-salt farms in the city’s southernmost district on the Gulf of Thailand, said Supachai Tantikom, an advisor to the governor.

For Thailand’s National Housing Authority (NHA) – a state enterprise that focuses on low-income housing – the 2011 floods reshaped the agency’s goals, and led to experiments in coping with more extreme weather.

The amphibious house, built over a manmade hole that can be flooded, was completed and tested in September 2013. The home rose 85 cm (2.8 feet) as the large dugout space under the house was filled with water.

In August, construction is set to begin on another flood-resistant project – a 3 million baht ($93,000) floating one-storey house on a lake near Bangkok’s main international airport.

“Right now we’re testing this in order to understand the parameters. Who knows? Maybe in the future there might be even more flooding… and we would need to have permanent housing like this,” said Thepa Chansiri, director of the NHA’s department of research and development.

The 100 square meter (1,000 square foot) floating house will be anchored to the lakeshore, complete with electricity and flexible-pipe plumbing.

Like the amphibious house, the floating house is an experiment for the NHA to understand what construction materials work best and how fast such housing could be built in the event of floods and displacement.


The projects in Thailand are a throwback to an era when Bangkok was known as the Venice of the East, with canals that crisscrossed the city serving as key transportation routes. At that time, most residents lived on water or land that was regularly inundated.

“One of the best projects I’ve seen to cope with climate-related disasters is Bangkok in 1850. The city was 90 percent on water – living on barges on water,” said Koen Olthuis, founder of Waterstudio, a Dutch architecture and urban planning firm.

“There was no flood risk, there was no damage. The water came, the houses moved up and down,” he said by telephone from the Netherlands.

Olthuis started Waterstudio in 2003 because he was frustrated that the Dutch were building on land in a flood-prone country surrounded by water, while people who lived in houseboats on the water in Amsterdam “never had to worry about flooding”.

His firm now trains people from around the world in techniques they can adapt for their countries. It balances high-end projects in Dubai and the Maldives with work in slums in countries such as Bangladesh, Uganda and Indonesia.

One common solution for vulnerable communities has been to relocate them to higher ground outside urban areas – but many people work in the city and do not want to move.

Olthuis says the solution is to expand cities onto the water.

Waterstudio has designed a shipping container that floats on a simple frame containing 15,000 plastic bottles. The structure can be used as a school, bakery or Internet cafe.

Waterstudio’s aim is to test these containers in Bangladesh slums, giving communities flood-safe floating public structures that would not take up land, interfere with municipal rules or threaten landowners who don’t want permanent new slums.

“Many cities worldwide have sold their land to developers… and now when we go to them, we say, ‘You don’t have land anymore, but you have water,’” Olthuis said. “If your community is affected by water, the safest place to be is on the water.”

Reporting by Alisa Tang, editing by Laurie Goering

Our Standards:The Thomson Reuters Trust Principles.

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Floating solutions for upgrading wet-slums

By Berry Gersonius

Innovations for water and development


Among the many challenges caused by the rise of global urban population is the accompanied growth of slum population. Around one billion people live in slums – most of them being close to open water. Being most vulnerable to floods, they are least attractive for upgrading investments. Neglected by civil authorities and confounded by a lack of space and money along with vulnerability, these already precarious slums are pushed into a negative spiral.

Using a bottom-up approach, the Floating City Apps Foundation, aims to upgrade waterfront slums with small scale instant solutions. Comparable to adjusting a smart phone with apps according to changing needs, the infrastructure in a slum can be adjusted by adding functions with City Apps.

These apps are floating developments built using a standard sea-freight container. The container is assembled in the Netherlands and shipped to the wet-slum where it is placed on a locally constructed floating foundation. Because of their flexibility and small size they are suitable for installing and upgrading facilities for sanitation, housing, communication etc. They can be added to a slum using the available space on water.


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Waterstudio team back from Korail slum

For the continuation of the Appgrading Wet Slums project, the Waterstudio team did a field research on the Korail slum in Dhaka

The Waterstudio team just returned from a field research with the goal to research on the possibilities of the implementation of the first City App in the Korail Wet Slum in Dhaka, Bangladesh.

Waterstudio together with Dutch Docklands support the Flood Resilient Group by conducting and sharing beneficial research on City Apps for Wet Slums. The Flood Resilient Group is a multidisciplinary research group affiliated to UNESCO-IHE and Delft University of Technology.

Waterstudio wins Architecture & Sealevelrise Award

Waterstudio has won the prestigious “Architecture & Sea Level Rise” Award 2012 from the Jacques Rougerie foundation with their entry: App-grading Wet Slums.

“Architecture & Sea Level Rise” Award 2012 for App-grading Wet Slums

Koen Olthuis and his Waterstudio team have won the prestigious “Architecture & Sea Level Rise” Award 2012 from the Jacques Rougerie foundation with their entry: App-grading Wet Slums.

Koen Olthuis’ architectural firm Waterstudio aims to upgrade slums by using floating urban structures called City Apps. City Apps are, essentially, floating functions that can easily be added to a city by placing them on water where needed.

Wet Slums are characterized by high density, a scarcity of free space and are located by the water. By using floating solutions new space is found on water. City Apps offer a flexible and adaptable design, creating solutions for the specific needs of each area. City Apps are catalyst functions.

A set of City Apps are developed for Wet Slums that provide food, sanitation, shelter and energy. Floating technology that has been used in projects for the “rich” will now be used for the people that really are in need.

City Apps are envisioned as products instead of projects which makes them reusable as they can be easily moved elsewhere once they are not needed. In this approach, City Apps are leased out to the local community.

The prize money provided by the foundation will be used to implement the first City App in the Korail Wet Slum in Dhaka, Bangladesh.

Official name of the award and foundation: Laureate 2012 – Promo Emmanuel Hervé – “Architecture & Sea Level Rise” Award from the Fondation Jacques

Rougerie – Génération Espace Mer – Institut de France.

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