CityReads│When the Water Comes

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When the Water Comes: How Cities Prepare for Climate Change

Sinking Cities, the four-part series of PBS documentary, examines how New York, Miami, London and Tokyo are grappling with the real-time effects of climate change.

Sources: https://www.pbs.org/show/sinking-cities/

https://www.thirteen.org/13pressroom/press-release/sinking-cities/

Picture source: http://www.pbs.org/wnet/peril-and-promise/video/sinking-cities-series-preview/

Half of the urban population lives within 60 kilometers of the sea; three-quarters of all large cities are located on the coast. As the earth warms, sea levels rise and super-storms become more frequent and intense, many of the world's major coastal cities may soon be under water. Billions of people are living in the shadow of an impending disaster. For example, in the last five years alone, the United States has been hit with 83 hurricanes, devastating cities from New York to Houston.

Sinking Cities, the four-part series of PBS documentary in 2018, examines how New York, Miami, London and Tokyo are grappling with the real-time effects of climate change. Sinking Cities is presented as part of Peril and Promise: The Challenge of Climate Change, WNET's national, multi-platform public media initiative reporting on the human impact of climate change, scientific solutions and innovation in resilience, mitigation and clean energy.

Featuring the world's foremost climate scientists, urban planners and expert engineers, each film presents what is unique about these cities when natural disaster strikes and examines the scientific and engineering challenges presented for the future. We also hear from those affected by a changing and extreme climate — how have they dealt with it and what are they doing to protect themselves for the future? The series also takes us deep inside the visionary, yet complex, infrastructure and engineering work already underway in each city to mitigate these current issues.

New York 

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New York is boldly built right to the water's edge. All along the city's coasts built on the landfill. In 2012, superstorm Sandy catches New York City by surprise. Sandy flooded 51 square miles-17% of the city. There's massive infrastructural elements for a city of eight million people that are in the flood zones. Transportation system, the tunnels, the subways, the electrical system, and a lot of other things were destroyed just by Hurricane sand.

New York city is on the edge of the continent, and that's what makes the city so special, and that also is what's threatening New York City going into the future. New York City faces two challenges. The first is the inevitable fact that the city lies in a hurricane zone, and storms will continue to come no matter what. The second is rising sea levels. With a six foot sea rise, a full 280 square miles of New York will be lost forever. With 520 miles of shoreline and no coastal protection, engineers and urban planners are tackling the problem with urgency and creative engineering.

The Big U is an ambitious megaproject that would project the 500-billion dollar business sector in lower Manhattan, the epicenter of the American economy. The Big U is a massive sea wall in places twenty feet high that would protect the most vital business district in the US from sea level rise of up to 15 feet. Its surface would be primarily parkland, with sports facilities, playground, bike and walking paths all along the ten miles of coastline.

Not everyone supports the Big U. Urban architect Pippa Brashear and her team propose the Living Breakwaters Project，that's a system of offshore breakwaters. Rather than a continuous sea wall, the breakwaters are a series of raised surfaces that slow storm surge. It's an old concept, but the ecological element is a new twist. The breakwaters will use some bio-enhanced concrete armor units to help jumpstart the ecology. The armor units can attract organisms, to recreate the aquatic habitat. The project are trying to actually restore the environment. The chemical content of the concrete has been adjusted to attract organisms.

New York's century subway system is a disturbing example of the challenges the city faces from rising seas, and powerful storms. So, how to protect the subway system form the disaster, the engineers use submarine doors that basically close each entranceway and some stop logs to prevent water from entering the subway system.

The new Whitney Museum appears to be one of the most flood resistant museum in the world. It was designed to be resilient against rising sea levels and storm surge. Its loading dock is protected by a waterproof flood door, designed and built by naval engineers. The outer concrete wall was reinforced to become 100% waterproof. Like the subway, the museum also has a ‘stoplog system'. A deployable barricade that can be installed in just eight hours in advance of an approaching storm. The building's mechanical equipments are all above that elevation, such as the elevators, power service, and pumps. The urban architect believes that the survival of New York depends on these new buildings that can endure the inevitable rising water.

Tokyo

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Tokyo is one of the world's most populous cities, and the economic engine of Japan. Many insurance companies around the world have assessed Tokyo as the most dangerous city in the world. Tokyo has the world's largest set of problems. Typhoons, tsunamis, earthquakes, rising seas, liquefaction and sinking neighborhoods threat this city.

Tokyo has the most advanced flood prevention system in the world. But the system didn't anticipate the changes this century brings. Sea levels continue to rise, typhoons grow stronger, and it rains more than ever. The aging population, plus the climate change, is a real ticking bomb for Tokyo. Engineers, planners, and civic leaders in Tokyo are addressing their epic challenge with technology, engineering and imagination seeking solutions to protect the city for decades to come.

Kamaishi's breakwater cost 1.6 billion dollars and took three decades to complete. But Japan's tsunami crushed this marvel of engineering like a toy and swept through the town in 2011. The sea wall is now being rebuilt. The new breakwater is designed to absorb its energy, and in extreme cases allow water to flow over top without ripping it apart.

Japan built a futuristic cavern to protect itself against water from above, below, or from the surrounding sea. It is the most advanced flood mitigation system on the planet. The system can hold up to 65 million gallons of water, and can pump it out as quickly as it comes in.

Tokyo is protected by a series of 44 flood gates along the city's many rivers. They are designed to stop storm surges as high as 26 feet. The highest ever recorded in Tokyo is only 10 feet. Even with sea level rise, the floodgates offer substantial protection to over a quarter of Tokyo. In the event of tsunamis or storm surges, the gates will be closed when the water reaches a certain level. If the water overflows the riverbanks, pumping stations are activated. When the water level on the inner side of a closed water gate rises with rain, they use the pumps to move the water accumulated inside the gate to the other side of the gate.

The city may have to consider ideas from outside of Japan. Kunle Adeyemi is an architect ,who are producing infrastructure for water culture. He has proposed an experimental design for low-cost floating habitats that can be used for housing, office space, or schools. He is trying to create a building system where the components are easy to fabricate in any kind of local region and assemble. It can easily be adapted to Tokyo`s unique environment. Temperatures rarely drop below freezing, and the structure can be made to ride out heavy rains and waves.

Engineer Toshio Nakajima has an even more ambitious idea. He has proposed an entire floating city in Tokyo Bay. Nakajima based his design on the Mega-float, basically a gigantic modular floating dock. The people live on the floating foundation, so that when it rains and the water level goes up, the city itself is raised with water. They also would have a big tank underwater,  located below the city, to store rainwater.

Water is the heart and veins of Tokyo. This city must learn to live with water, as opposed to fighting it.

London

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Flooding has become a commonplace in London. London faces three challenges. Summertime rainfall in the UK has increased 20% in the past decade. The city is densely developed along the Thames River floodplain, about 75% of this massive urban area is completely paved over, meaning all that rain has no place to go. And, the legendary Thames is handing more water than ever, as sea levels rise all around the island nation.

The storm surges have flooded London throughout history. In the aftermath of every flood or near miss flood, the barrier in Central London which protect the city from the river have been strengthened. The Thames Barrier, a 600-yard-long flood gate that runs from New Charlton to Silvertown across the Thames, was finished in 1982. Normally, the barrier remains open so boat traffic can reach the Port of London. But when a storm surge approaches from the North Sea,10 curved steel gates rotate up from the riverbed. This forms a solid wall against millions of tons of water that would inundate London. For three decades, the Barrier has kept the city safe from storm surges. But In some cases, they have been over-topped. More rain and rising seas will put still more strain on London's infrastructure. All of London's current defenses will soon need upgrading or replacing. The government and public utilities are searching for solutions.

London's TE2100 plan is tackling rising seas and increased rainfall with multi-billion dollar  infrastructure projects and with small-scale solutions.

The Thames Tideway Tunnel is designed to channel the water from overflowing sewers before it gets to the river. It is a tunnel than 200 feet below the Thames and running along roughly the same path. It is a 25km long tunnel, which lies across the London basin off the Thames. If London encounters flood, It ensures raw sewage no longer get into the Thames by diverting the contaminated overflow to upgraded treatment facilities.

People have paved over large parts of the landscape. A lot of rain cannot penetrate the land, so it is prone to flooding. The Sustainable Drainage System (SDS) can probably solve this problem. SDS offers a range of drainage solution depending on the site. The landscape architects use permeable block paving to deal with water. The rainwater can run through the block paving and gets stored underneath. In the busy road, engineered tree pits are thought to be the best way to deal with the sediment. The water in the carriageway flows into the tree pit by the drain. There are lots of boxes for water under the tree pit.

As London looks to the future, it also looks to the past for overlooked options. The project, run by David Harding, revolves around a network of lost rivers that lie beneath London. The project aims to restore some of the more natural drain age of London. So far, over 11 miles of lost rivers in London have been “daylighted”.They are all used to discharge the flood. The project is already having an impact, reducing the amount of rainwater flowing into the Thames system.

The organic approach to flood prevention can be a necessary complement to large infrastructure like the Barrier. The First Farms Wetlands are treated as a flood storage in Enfield in north London.

Miami

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Miami, a city facing seawater inundation. With Atlantic Ocean surface temperatures rising, there are more hurricanes in the 21st century. The hurricanes destroy the Miamians'homeland and cause the flooding. Miamians is also facing a new kind of flooding-which comes from below the ground. Because of rising sea level, high tides often push up Miami's drainage system and into the streets, carrying debris along as they go. This kind flooding is also related to the city's unique foundation. As the ocean levels rise, seawater pushes up through the porous rock. It infiltrates the natural fresh water aquifer, that also contaminates Miami's drinking water. Miami's average elevation is only 1.8 meters. Two to three feet of sea level rise basically outride Miami, and puts it below sea level.

Miami is considered the most at-risk city worldwide for protential damage due to rising sea level and storm related flooding. More than $416 billion dollars in real estate is at risk here. Today,developers continue to build on Miami's most vulnerable ground . But it is a huge risk.

When the people originally built Miami, the beach was supposed to be for the richer. The poor and minorities were pushed to the center of the city because of red lining and racist. But ,some buyers now prefer higher ground in the city center where they won't be affected by flooding. In Miami, the term “Climate Gentrification” has been coined to describe how some people move away from the shore into the traditionally less-desirable lower-income neighborhoods.

Rich or poor, officials in Miami face the challenge of making sure everyone is protected from Miami's rising sea. A citizen sea level rise advisory committees that is made up of engineers ecosystem naturalists, land use attorney, architect, and developer. This committees brings together suggestions and voices from all society.

Miami is currently designing infrastructure for the next 40 to 50 years, to two and a half feet of sea level rise over that time. They build strong flood barriers ,pump ,piping systems and elevate the land over time to live with the water.

All new developments along the city's coast must be raised by almost 13 feet. They must also be built to withstand flooding without being crippled in the event of a 15-feet storm surge. The government issues regulations on the use of buildings and land, such as any kind of mechanical room must be built on the high floor. The government also creates the natural barrier by restoring and maintaining mangrove forest.

Cities have always been vulnerable. Cities also have this extraordinary way of being resilient and building back. It's a transformation that has to happen if cities are to survive, and even thrive when the water comes. Human beings are using their intelligence to protect themselves from disaster. But human beings should also reflect on the way of intervening in nature. The knowledge and intelligence that we respect and admire should not be the beginning of environmental destruction, but should be the source of harmonious symbiosis with nature.

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