Tokyo Shotō - From 0-Meter Zone to an urban archipelago

TOKYO SHOTŌ From 0-Meter Zone to an urban archipelago

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TOKYO SHOTŌ From 0-Meter Zone to an urban archipelago

30 ECTS-points Master Thesis in Landscape Architecture Andreas Jønck Faartoft LNC923 Mie Højmose Dehlsen VND919 Supervisor Gertrud Jørgensen

Marts 2017

Andreas Jønck Faartoft

Mie Højmose Dehlsen

Faculty of Science Department of Geoscience and Natural Resource Management

4

Project

ABSTRACT This thesis rethinks the current approach towards mitigation of the flood risk of the 0-Meter Zone in Tokyo, Japan. A large area, currently situated below the 0-meter elevation mark and protected by levees, is in high danger of flooding due to climate changes and insufficient levees. This thesis introduces a vision for an alternative future for inhabiting the 0-Meter Zone, by suggesting an archipelago of islands, utilizing the water to reduce the consequences of a future natural disaster. One specific high-risk area is chosen to demonstrate the general principles of the vision.

The history of Japan and Tokyo, along with a description of the cultural significance of water, the current protective measures and planning systems are covered to give a comprehensive overview of the complex current situation. Based on this, a vision is presented as an alternative approach for the future life of the 0-Meter Zone.

The vision is concretized by redesigning one of the most critical areas within the 0-Meter Zone. Design principles inspired by the existing area are defined, based on a series of analyses of the current physical structures. In addition, the new design introduces core functions of how a water city can be structured, while enhancing different ways of living in coexistence with the water.

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Table of

CONTENT

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Project Motivation Problem & aim Method Setting the scene

9 11 12 14

Japan Introducing Japan

General issues

The rise of urban Japan Planning system

16 18 21 24

Tokyo Introducing Tokyo

Climate

Climate Change

Demography

The beginning

The modernization

26 28 29 31 32 34

Rivers Introducing rivers

Culture

Measures

Problems

Worst case

38 40 42 46 48

0-Meter Zone Introducing the 0-Meter Zone Risk analysis Development area

50 56 57

Tokyo ShotĹ?

Vision of Tokyo ShotĹ?

58

Hirai Introducing Komatsugawa Hirai History Present Structural analyses

62 64 70 74

Shin-Hirai Introducing Shin-Hirai Design objectives: Water & Living Island foundation Layers overview Gradient housing Structural layers of Shin-Hirai Stakeholders Water Numbers of living Development phasing

82 84 86 88 90 98 112 114 115 116

Outro Discussion Reflections

124 125

References

126

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Project

MOTIVATION Andreas In 2016 I did a semester of studies in Urban Engineering at the University of Tokyo. During my stay, I was introduced to various spatial and urban challenges of Tokyo and Japan. One of the issues which especially woke my interest was the imminent threat of flooding of Tokyo.

I have a particular interest in urbanization and how climate change threatens the livelihood of many of the modern cities we know today.

The threat of a flooded Tokyo added to an existing frustration of mine. A general frustration of how climate change issues do not get politically prioritized, and how it seems that we as citizens of the modern world keep demanding the possibility of living wherever we want, regardless of geography and obvious natural conditions.

The issue of having a densely populated ‘below 0-meter area‘ in a modern city like Tokyo seems absurd but interesting. With this starting point my curiosity was piqued as well as an urge to introduce new ideas and maybe even to provoke a bit.

Mie The problems occurring as a consequence of climate change is of great interest to me. Especially the changed precipitation pattern, leading to more flooding in the cities, has since I wrote my Bachelor thesis been a focus of mine. I like to think of the current changes as an opportunity for us to restructure and reconstruct the physical spaces of our city, to wipe the blackboard clean and start over with more care and awareness. But often things cannot be deleted, because of the complexity in and of our cities, which can lead to much frustration for a Landscape Architect.

My final school assignment will therefore be used to aquire new knowledge, discuss an interesting topic, introduce crazy ideas and push boundaries for conventional thinking.

When Andreas presented the issues of Tokyo’s 0-Meter Zone in the spring of 2016, I immediately found it interesting. I had never heard about this issue in a Japanese context before, and I felt curious to test how it is to work on such a large scale in a foreign country. The extreme situation inspired a desire to push ordinary boundaries, to test crazy ideas and to discuss how we should live with water in the rapidly changing world.

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Tokyo

Elevation map of the lowlands surrounding Tokyo

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Project

PROBLEM & AIM Large parts of Tokyo are located below the 0-meter elevation mark. Due to the geographical location of Japan the country is confronted with various natural threats every year with flooding and earthquakes amongst the most severe ones.

Tokyo is highly dependent on physical structures protecting the lowlands from being flooded, many of which are assessed to be insufficient in case of a natural disaster. Many of these structures are therefore planned to be either reinforced or completely redesigned, but as individual improvement projects. Furthermore, these structures divide the city, removing understanding of the water and most natural interaction with it during everyday life of the Tokyo residents. The main question for this thesis is: What are the current threats of living in areas such as the 0-Meter Zone of Tokyo and how can an alternative future for urban life, in coexistence with water, be envisioned here?

The aim is to create a vision of how to rethink water and city as a form of mitigation to the threats of flooding. The new design should investigate how a water city can be structured, while enhancing different ways of living in balance with the ever-changing nature.

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Project

METHOD During Andreas’ exchange studies at the University of Tokyo he became aware of the issue regarding the 0-Meter Zone. We started researching the topic while Andreas was still in Japan. The initial research consisted of general investigatins such as reading articles on the subject, talking to Japanese co-students and professors who also helped us finding GIS-data as well as official documents.

Mie joined Andreas in the end of his studies and made a site visit to some of the areas at risk to get a sense of the scale of the problem. Before leaving Japan we met with Ikuro Kasuga, Assistant Professor in the field of water environment to discuss the issues in more general terms. The purpose with this was to get as broad a knowledge as possible before returning to Denmark.

Back in Denmark we started investigating maps and literature to gain a more thorough knowledge of the issues as well as a general understanding of Japanese history and culture. Early in the process we travelled to the Netherlands to seek inspiration and references on how to coexist with water.

Initially we focused on the full stretch of the river, aiming to develop a comprehensive river plan to avoid flooding downstream. However we ended up focusing on the local physical structures along the river instead. We felt that focusing on the full river course, limit us to existing solutions rather than taking visionary viewpoint. We ended up leaving the framework defined by the current reality and propose an alternative approach.

To create a foundation for further design work, we met with a Danish expert in water flow dynamics, Associate Professor; Verner Brandbyge Ernstsen.

It has been a challenge to work in an entirely new context with such an extreme challenge. This has required a different approach to urban planning than we are used to. For example, the question of preservation has been haunting us throughout the process, as it is usually of great consideration in other projects, but found it necessary to minimize the focus to allow for greater ideas.

Vision development throughout the process

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GIS-DATA Most of the data available were both in Japanese and in nonstandard formats, meaning some conversion and translation work was necessary. The process of collecting, converting and processing data has been time consuming but a very useful source of information.

The GIS-based data made it possible to do very detailed studies of the existing physical structures, land use and terrain.

TERRAIN DRAFTING Terrain is characterized as 3-dimensional, which is not always visible in the drafting process, so we wanted to explore the options of an intuitive digital 3-dimensional drafting tool. Something we didn’t have much luck with. Most software found was still based on the presence of either contours or a detailed mesh of points. None of the investigated software were intuitive enough to be used as a discussion tool. Instead we built a physical sandbox to use as the basis for discussing different scenarios. The sandbox was very useful to us in the early discussions, but lacked the sufficient detail to use it for actual modelling.

VISUALIZATION TOOLS We have used sketching as a tool for discussion and design development. To visualize our final proposal, we have used various digital drawing software.

LITERATURE REVEIWS Most official documents were only available in Japanese, which has been a natural limitation to the amount of in-depth reviews of these sources. But with the help from translation tools such as Google Translate, official maps, reports and statistics have to some extent been useable.

INVESTIGATION TOOLS Due to the location and scale of our project area it has not been possible to visit the full area, Google Maps has therefore been an important tool in the investigation process.

Study trip

Site visit Process

Problem investigation

Analysis

Design

Sand model

Tools

3D GIS Visualization tools Litterature review

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Project

SETTING THE SCENE Sandy beaches, vibrant harbour fronts, coast promenades and exclusive waterfront apartment buildings. The coastline has been attractive for decades. The finer the sea view, the higher the land prices. Globally, millions of people currently inhabit the coastal areas; where the mountain rivers expand and flow into the ocean; where storms deliver massive waves; where tsunamis hit civilization and where climate change is claiming land. Why are people still living in these regions of ‘brutal’ nature?

With the rising threat of climate change, affecting the amounts of water in storms, rivers and oceans, has time come to adapt to the changing nature, instead of stubbornly claiming the right to live, where we have always lived?

Humans have historically been attracted by favourable landscapes, which often consist of various elements, a matrix of various types of nature and habitats. Animals often exist in the border zone of different landscapes, close to shore, at the edge of the forest or by the river bank. As humans, we could feed from these places. Later, the water defined our possibilities of transportation and communication, and even later we longed to these diverse and dramatic places for the aesthetic values or even in the search of a greater meaning with life. Today some of the largest cities of the world are located on the coast. As these cities grow bigger we move the urban boundaries and conquer land, which used to be covered by water.

We re-direct rivers to concrete beds or pipes. We limit the rivers to strict narrow courses and often remove the potential for biological activity in these water bodies. We build large constructions to protects us from the raging ocean waters, and enormous dams to control the water from the mountains. All this done so we can claim land and extend the city into the flood plains and wetlands. The high grounds are no longer enough for us.

Given the current climate change predictions it is now necessary, more than ever to discuss to what extent we should still be living in the lowlands. And if so, on which terms.

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In Tokyo, the uncontrolled city development these border lands of water and land, has had significant consequences for its residence. The harvest of groundwater has caused areas to subside, and intensified the need of separation between people and water. Millions of people are living in these areas, despite the risk of flooding. The consequences of such a disaster here would be catastrophic. Hundreds of thousands of homes under water and many lives would be lost. Events in cities like New Orleans and in Japan’s own city of Jōsō, have raised questions about the safety of living in low-lying areas. The situation is complex; assets worth of billions as well as culture and history are tied to our cities, and it is hard to even think that it could be different.

But what if it could?

Is it time for us to listen to what nature is telling us, instead of keep building taller and intensify the separation between water and people? Is it time for us to decide how we should live with nature in the future?

This project aims to open a discussion about where people should live in the rapidly changing climate. How society can adapt rather than fight the uncontrollable forces of nature. The project should be considered as an input and inspiration for thinking differently and as an alternative approach; rather than keep fighting the ever-changing nature we should embrace and enhance it by living with it – not protecting us against it.

Extreme circumstances call for extreme measures.

Economic and organisational considerations along with issues regarding preservation are set aside in favour of visionary thinking and the discussion on future city adaptation.

If this booklet is read with an open mind, we hope that interesting discussions will arise.

Happy reading!

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Introducing

JAPAN In the most eastern part of Asia on the verge of the Pacific Ocean lies Japan, home to approximately 127 million people. Due to its location at the junction of 3 major tectonic plates Japan is characterized by hundreds of volcanoes and a vast amount of mountainous areas making most parts of the country inhabitable.

Less than 25 percent of the country is suitable for either urban development or agriculture, resulting in most cities being located along the coastline or in the lowlands.

The climate varies from subtropical along the pacific coast to temperate in the inland region. At the same time as people can ski on the northern island of Hokkaido, it is possible to swim in ocean by the southern islands of Okinawa.

The geography of the region is results in Japan being hit by a variety of natural hazards on a regular basis; volcanic eruptions, typhoons and earthquakes followed by the risk of tsunamis. Besides these more extreme events, heavy rainfall during the rainy season and melting water from the mountains often causes floods in urban areas further downstream. Located in a region regularly visited by the powers of nature the country has been forced to an innovative way of thinking to ensure the security of its citizens.

Disaster prevention is therefore an issue highly present in the field of architecture and urban planning.

Japan has a strong tradition of engineering and solving natural threats with highly advanced technical solutions. Unfortunately, Japan is not spared from the global changes of the climate. Due to the vulnerable location of several of the major cities along the coast and in the lowlands. These urban areas are imperilled not only from the rising sea, but also from the heavier and more frequent rain events causing rivers to breach their levees and leaving large urban areas under water.

Mountains & Forests

Urban

66 %

9%

Agriculture

Rivers & Lakes

12 %

4%

Land use of Japan (Statistic Bureau, 2016) *9% Other 16

5.706.950

42.434

km2

of land

127.083.000

364.485

Tokyo

km2

of land

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Japan

GENERAL ISSUES Geology Japan experiences approximately 1500 earthquakes a year, which makes earthquake a very integrated part of everyday life.

Earthquake proofing is a natural part of the city; ranging from strict building regulations, over designated and signed evacuation sites, to loudspeakers in the streets to alarm people of upcoming tremors.

With earthquakes being an unavoidable natural phenomenon, the citizens have adapted to this, and only major earthquake have significant effects on the country. But there is an underlying fear of large earthquakes such as the TĹ?hoku Earthquake in 2011 or The Great Kanto Earthquake in 1923.

It is commonly known that major earthquakes have historically shown a pattern of repetition. This has lead experts in the field to expect that a major earthquake in magnitude of the TĹ?hoku Earthquake could happen in the Tokyo Region, at any moment now. (Simons M., el al., 2011)

Sea of Japan

Pacific Ocean

East China Sea

Registered earthquakes in Japan from November 2015 to November 2016 (JMA, 2016)

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Changing demographics Japan has become known as an “aging society”, where the population size is declining with such a rate that it will cause problems maintaining the necessary work force in the future. With a fertility rate of only 1,42 (births per woman), Japan is ranked amongst the lowest compared to similar countries. (World Bank, 2015) This is due to various factors such as a strict social code and more focus on career amongst the younger generations. In addition, the current life expectancy for women (88,5) and men (81,7) is increasing and whilst more people are becoming older, it is predicted to cause a variety of challenges such as rising expenses to health care, pension costs along with new issues regarding the design of cities with a high concentration of elderly citizens (CIA, 2017). In order for a society to be in balance, it needs to have a sufficient amount of people in the working-age to support the remaining population. This demographic issue has put the nation of Japan in a critical situation.

Climate change The exposed location of Japan in the western part of the Pacific Ocean has a great influence on how global warming will affect the climate of the country. The average temperature for all regions is predicted to rise about 3.0°C by the end of the 21st (Japan EVN, 2012), which will influence the future weather system and most likely increase the frequency and severity of adverse events. The precipitation patterns will be affected. An increased frequency of heavy rain and intensified typhoons will lead to more water-related disasters. Landslides, external flooding from rivers and internal flooding caused by insufficient sewer systems are some of the consequences already happening (Japan EVN, 2012). Also, the sea level will be affected; it is estimated to rise by 60 cm by the end of 2100. This will have a great impact on the coastlines of the country making these areas more vulnerable to general flooding and flooding during storm surges (Japan EVN, 2012).

2010 128.070.000

140

100 80 60

Inhabitants over 65

Population in Japan (millions)

120

40 20

1960

1975

2000

2025

2050

Estimates

Demographic predictions for Japan, (World Bank, 2015)

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Matsumoto Castle, Feudal castle of the region

Japan

THE RISE OF URBAN JAPAN The urbanization of Japan began more than 400 years ago, and has laid the basis for the structure of many contemporary cities we know today. Like in many other countries this structure is based on politics and war of the past.

The Tokugawa Era (1603 - 1868) began after a long period of war, when Tokugawa Ieyasy finally defeated the rivalling clans and was appointed Shogun (military ruler) by Emperor Go-Yōzei. He then established the Tokugawa Shogunate (government) (Wikipedia, 2017) and during the following decades, he introduced a new system of social and political control of the newly unified nation.

(Sorensen, 2002:13-15). An important part of this system was the ‘One Castle, One Domain’, requiring the ‘daimyo’ (feudal lord) to concentrate all military and administrative functions of the region in one castle town. Many ‘daimyo’ decided to relocate their castle to more favourable locations, usually in the agricultural plains which formed their economic base. The location was usually along rivers and highways which gave an advantage in transportation and communication, but just as well as source of irrigation of the crops. This relocation was the starting point of the urbanization of the flood plains (Sorensen, 2002:13-15).

As part of this, most samurais, which were part of the military class just below the ‘daimyo’, were relocated from their rural properties to the castle towns for administrative functions and as protection for the ‘daimyo’. Now, the samurai could no longer sustain themselves by living of their land as they used to. This led to a new demand of goods and services in the towns, causing many merchants and artisans to move there for business, as well as people trying to make a living as servants. These people became part of the class known as commoners, which resided in the lower city in contrary to the daimyo and the more influential samurai living in the higher city.

1603

1868 Tokugawa

1912 Meiji

1926 Taishō

1989 Showa

Present Heisei

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The castle towns then grew bigger as the large influx of new commoners rose and especially the low city became more and more densely populated. In some cases, the low city grew to the extent that the daimyo had to relocate the agriculture further into the lowlands. By the end of the Tokugawa period (1603 – 1868) it is estimated that the population of Japan grew from around 18 million to more than 30 million people, of which around 16 percent were living in urban environments (Sorensen, 2002:12).

By the time of the industrialisation Japan was probably one of the most urbanised countries on earth and Tokyo had long been the world’s largest city (Sorensen, 2002:12).

With the beginning of the Meiji Era (1868 – 1912) came the abolition of the feudal class society, leaving the peasantry with equal rights.

The farmers became land owners, were given the freedom to buy and sell land and even the possibility of moving away from the land they were previously forced to stay in. Many people sold their land to the advantage of urban development. However, the uncontrolled expansion of the cities into the agricultural land, led to a highly-scattered development. The historical lack of urban planning policies in Japan could be blamed for the result: Urban floodplains.

Along with the development of these urban floodplains is the demand for more space often increasing at the expense of open water bodies. Many water courses have been relocated to more confined concrete channels or pipes, leaving the present society with the major concerns of urban flooding.

1603

1868 Tokugawa

22

1912 Meiji

1926 Taishō

1989 Showa

Present Heisei

Agriculture encapsulated by urban development

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Japan

PLANNING SYSTEM The overall urban planning system of Japan is structured through several layers of hierarchal organized plans.

On a governmental level both a National Spatial Strategy and a National Land Use Plan is formulated. These define the vision and direction of development on a national spatial level. Within this political framework each of the country’s 8 regional blocks describe a regional strategy. The strategies altogether create a vision for the nation and the regions for the years to come (MLIT, 2003).

The National Land Use Plan forms the basis of the spatial management. In addition, to develop a Regional Development Plan each regional block defines the expansion of urban areas, new towns, industrial development and both traffic and water related infrastructure. Within this framework each prefecture will develop a Land Use Master Plan, which basically classifies the land as either Urbanization Promotion Area or Urbanization Control Area. This is done, to hinder sprawl developments. A District Plan is created by the municipality covering areas of various sizes. The content must be within the framework described in the Land Use Master Plan. The district plan is only created for areas of development, and contains all the specific regulations, such as building sizes and ratios, land use, functions etc. Land use definitions are divided into 12 different zones, specifying an area as residential, commercial, industrial or a mix (MLIT, 2003).

Various extraordinary measures are available for an authority to secure efficient urban development. One of the tools is called Urban Land Readjustment, which is a tool of urban renewal. It originated in the beginning of the 20th century as a tool to redistribute agricultural land to make room for roads and irrigation channels.

Today, it has been widely used in the urban context, mainly to upgrade dense areas of low quality housing or for infrastructural projects. It is very useful for large-scale projects due to the general complexity of Japanese cities.

When a project is emerging, all the property in the specific area is pooled together and then either redistributed back to the owners or compensation is given to the owners. One of the main requirements is that 2/3 of the land owners must agree to the proposal (GDRC, 2017).

Public participation is a rather new term in Japanese city planning.

The process of public participation relies on respect and cooperation from the developer’s side with only weak powers of the authorities to make sure the developers keep to their promises.

It has mainly been a media for small scale improvements of the local environment and has yet to become an integrated part of urban planning concerning large scale issues such as improvement of existing residential areas by widening narrow roads, providing parks, building community centres and similar local facilities.

(Sorensen, 2002) 24

Japan

Governmental level National land use plan

National spatial strategy

Political framework Region KantĂľ

Metropolitan regional development plan

Regional strategy plan

Prefectural level Land use masterplan Prefecture Tokyo

Municipal level Municipality Edogawa

District plan

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Introducing

TOKYO Tokyo Metropolitan The official capital of Japan is one of Japan’s 47 prefectures.

It is home to approximately 11% of the Japanese population and is considered one of the most populated areas globally.

Tokyo City (23 special wards) Within the Tokyo Metropolitan region an area known as “the 23 special wards”, is also called Tokyo City. This is considered the heart of Tokyo. The wards are subdivisions of the city and each ward functions as a city itself.

13.649 574 2188 of land

km2

10,7% of national

population

Tokyo Metropolitan

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Tokyo City

9.240.100 66 23 627 m2 /capita

km2 of land

602.504 86,4 143m of land

km2

special wards

Copenhagen 2

/capita

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Tokyo

CLIMATE Jan

Fe

c

De

b

Ma

No Koyo (A v utu mn co lor s)

200

r

0

Apr

Sakura season

Oct

100

h Typ oo

ea

Ma

y

ns

p

Se

so

n Au

g

R ainy s e a s o n

n

Ju

Jul Sunshine (h)

Number of sunshine hours and seasons, Tokyo Metropolitan area (JMA, 2017)

500

40

Max

30

400

Med Min

300

10

200

0

100

-10

0 Jan

Feb Mar

Apr May Jun

Jul

Aug

Precipitation (mm)

Temperature (C )

20

Sep Oct Nov Dec

Temperature and precipitation, Tokyo Metropolitan area (JMA, 2017)

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Tokyo

CLIMATE CHANGE Urban Heat Island Tokyo is dominated by asphalt, concrete and lack of green areas.

The city is therefore experiencing a very high degree of urban heat island effect, causing unpredictable and very intense localized weather events; such as thunderstorms and short intense rain events. In fact, during the summer, Tokyo can sometimes reach temperatures similar to those experienced on the tropical islands of Okinawa.

Typhoons and precipitation Hazardous typhoons will more often bring extreme high tides towards the city through Tokyo Bay (JMA. et al, 2012). The increased precipitation will lead to an increased risk of internal flooding because of insufficient sewer systems, also known as “the bathtub effect”, where the water is trapped in low-lying areas below sea level. Additionally, external flooding from the city’s many big rivers may result in unimaginable economic disaster and human losses.

Sea level Like many other metropolitan cities located on the coast, the city of Tokyo has a dangerous relationship with the water. Large parts of the city already lay lower than the average sea level, but along with the climate change and the predicted sea level rise, the size of this area will increase. Furthermore, JMA (Japan Meteorological Agency, 2012) predicts that a rise in global temperature of 1,3º Celsius could increase the current area of the Tokyo Bay by a factor 1,5 (JMA. et al, 2012).

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30

Tokyo

DEMOGRAPHY

60

Inhabitants over 65

Population in Japan (millions)

Decreasing city population An overall decrease in the Japanese population will not only have major impact on a national level, but also on the Tokyo Metropolitan area specifically. Population projections estimates that the population of Tokyo Metropolitan will decrease to 7,13 million by 2100 (UN, 2014). This will inevitably affect the spatial 2010 structure of future Tokyo. A population cut in half will reduce the 128.070.000 140 need for housing, which may cause empty houses and apartments in 120 the cityscape. This could result in a scattered city, with a high concentration in some areas leaving other areas scarcely inhabited.

100 In isolation, this a major problem, but if incorporated into strategies it could be the catalyst for new possibilities of spatially restructuring 80 the city.

Aging 40 city Age forecasts for Tokyo indicate that by year 2100 the population 20 above the age of 65 will be 3,27 million. By then 40% of the population of Tokyo Metropolitan will not be a part of the workforce, 1960 a lack 1975 2000to cover municipal 2025 2050such causing of public funds expenses as road maintenance and garbage collection (Statistic Bureau, Estimates 2014). Moreover, with such a drastic demographic change the needs and usage of the city will also change. Along with changing demographics the housing requirements will change as well.

Accessibility should be improved as well as distances to daily urban necessities, such as shopping and transportation being shortened.

(OECD, 2015) Lastly, elderly people are more vulnerable to natural disasters, both in terms of the ability to evacuate and subsequent sickness as well as mental and physical stress (Muramatsu, 2011).

15 2020 13.350.000

14 13 12 11 10

Population in Tokyo Metropolitan (millions)

9 8 2100 7.130.000

7 6 5 4 3 2 1 0 1800

1850

1900

1950

2000

2050

2100

Estimates

Decreasing population in contemporary and future Tokyo Metropolitan (UN, 2014)

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Tokyo

THE BEGINNING The history of Edo, today known as Tokyo, reaches back approximately 400 years. Edo emerged near the riverbanks of the Sumida River, a location which gave its name. ‘Edo’ means estuary and refers to the place where the rivers reach the bay of Tokyo. It was not until Tokugawa Ieyasu, the last military leader of Japan, established Edo as the cultural and political centre that the city grew significantly. The city was later named as the capital of Japan, and then rebuilt as a castle town around the old Edo Castle. Edo was afterwards called Tokyo meaning ‘east capital city’ (Sorensen, 2002) The urban growth of Edo was highly affected by the social structures of the society. In fact, your social status was defining in which area you could live. The elevated castle of Edo was the home of the ‘daimyo’, the feudal lord of the region, while the surrounding quarters belonged to the samurai under his command. This area was safely situated in the hills of Edo and would later be known as Yamanote, literally meaning ‘mountains hand’. Outside the castle walls, primarily to the east, the ‘low city’ with the commons district slowly developed. The ‘low city’, sometimes referred to as ‘Shitamachi’, was built on reclaimed delta land with channels and rivers dividing the land. In contrary to the ‘high city’, the common people of the ‘low city’ often experienced flooding. In attempt to mitigate the flooding threat and distribute the water around the ‘low city’, channels were constructed. Though the channels were interfering with the landscape, they were carefully laid out to follow the terrain and to respect the existing nature (Sorensen, 2002) Although the people of the lowlands always lived in danger of flooding, there has over time been a continuously rechannelling and construction of new rivers along with the technological development. With this slow change of the natural water cycle, the respect and understanding for the natural setting of water has been lost, and thereby made the danger of flooding even greater (Graaf and Hooimeijer, 2008).

1603

1868 Tokugawa

32

1912 Meiji

1926 Taishō

1989 Showa

Present Heisei

Nihonbashi Bridge in the Rain, 1832

33

Tokyo

THE MODERNIZATION The development of Tokyo over the last century has been highly influenced by the generally uncontrolled urban development and several destructive events. By 1920 the city of Tokyo had around 3,7 million residents and was already by then, one of the largest cities in the world. After The Great Kanto Earthquake in 1923 a devastating 2/3 of the city was destroyed and with an almost blank urban sheet, the development was focused on the rebuilding of housing, improving the former road system and fireproofing vulnerable neighbourhoods (Sorensen, 2002). The question of parks, open and public places drowned in the great demand of housing.

While the city became more densely populated over time, the fear of flooding increased and for good reason. Several times, the city experienced levee breaks, a catastrophe for the thousands of people living in the affected areas. As a countermeasure, multiple actions were taken to secure the safety of the Tokyo citizens. At the same time as the development of Tokyo’s comprehensive railway system began, the rivers lost their importance as infrastructural lines. Shops, warehouses and even theatres were no longer dependant on the location near a river, and people’s interaction with surface water was reduced.

1603

34

Tokugawa

1868

Meiji

1912

Taishō

1926

Showa

1989

Heisei

Present

The Great Kanto Earthquake, 1923

Redirected river in Tokyo, 2016

35

In the aftermath of WW2, a big part of the city yet again had to be rebuilt, and the debris from many of the bombed buildings were used as landfill of existing rivers and lakes, to utilize the space. As urbanization accelerated through the 1960’s due to high economic growth, the city expanded to the west, and to an almost greater extent to the east, where the floodplain was starting to become more densely populated. The transformation from a city on water to a city on land was intensified (Graaf and Hooimeijer, 2008).

A denser populated Tokyo meant a greater demand of the limited water resources beneath the city. The continuous pumping of groundwater, later lead to the subsidence of the already lowlying part of the city, in some places more than 4,5 meters. The exploration of groundwater and thereby the sinking has stopped, but a vast area lies now below sea level of Tokyo Bay. During the time of sinking, improvement of the river system were necessary, to meet the safety standard for protecting the people living along the big rivers (Graaf and Hooimeijer, 2008).

The modern development, and especially the Olympic games in 1964 brought along the construction of many highways, which due to lack of space and property rights were constructed on top of many of the city’s rivers. Slowly the water was removed from the cityscape, and with the implementation of the sewer system in the same decade, channels and small streams were covered as well. The water which used to be a great part of the city was now buried under the need for progressive modern city development (Graaf and Hooimeijer, 2008).

1603

1868 Tokugawa

36

1912 Meiji

1926 TaishĹ?

1989 Showa

Present Heisei

Tokyo after WW2 bombing, 1945

Nihonbashi bridge, Tokyo

37

Introducing

RIVERS The rivers of Japan are generally characterized by their short lengths and steep gradient created by the mountainous landscape. The common source is found in the mountains from where it flows through the narrow valleys onto the plains through the agricultural lands before reaching the urban areas and finally merging with the oceans.

Various measures have been taken over time to regulate the rivers and avoid flooding of both the major populated areas as well as the less populated rural lands.

The responsibility of constructing and maintaining the rivers and its measures is divided between authorities and specified in the River Law. A-class rivers, are those of national importance, both regarding economy, as well as the safety of the river adjacent society. A-class rivers are managed by the Ministry of Land, Infrastructure, Transport and Tourism. Other large rivers are categorized as B-class rivers and managed by the prefecture, while the smaller rivers are managed by the local municipality (Graaf & Hooimeijer, 2008).

Arakawa The river originates at Mount Kobushigatake at an elevation of 2475 meters and flows 41 km. through the mountains, 24 km. through the lower hilly regions and finally 108 km. through the vast plains of Kanto before reaching its final destination in Tokyo Bay. The last 22 km. of Arakawa was in 1911 reconstructed as a floodway with a varying width between 445 and 588 meters. During the 20 years, the construction lasted, 1300 households had to be relocated (Graaf & Hooimeijer, 2008) Arakawa is categorized as an A-class river, meaning it is considered as one of the major rivers of Japan. Therefore, the condition of the river and the related measures are of great importance to ensure the safety of the people and the society.

Along with the changing climate the current condition of the river is assessed to be insufficient, and various measures in the pipeline; none of which seem visionary nor long sighted.

River classes

A Class

B Class

Other

Ministry of Land, Responsibility

Infrastructure and Transport

Prefectures

Municipality

River Bureau

Responsibility overview (MLIT, 2009)

38

9.300.000

inhabitants of the catchment

2940

km2

catchment area

173

km

length of Arakawa

Arakawa catchment

“THIS IS NOT A RIVER, BUT A WATERFALL” N

Johannis de Rijke (Dutch engineer)

0

5 10

20 Km 39

River

CULTURE Water has always been a vital resource for the Japanese people as it is an important source for food. Rice and fish are both essential parts of the daily diet of most Japanese people. This historical dependency on water in Japan has embedded water in the society not only as a resource but as a cultural and religious element.

In areas where people have been dependent on water as their livelihood such as fishing ports or agricultural villages, shrines dedicated to this natural element are often present.

Shinto is a traditional Japanese religion practised by around 80% of the population. In Shinto, nature plays a vital role. It is a belief in a divine energy manifested in nature, such as rivers, waterfalls, trees or even places. Water is included in many of the religious rites and is an important part of the ‘Harae’ (the rite of purification).

Harae is still being used, not only in a religious context, but also in contemporary culture as a kind of blessing. For example, in the opening of new buildings, shops or before a newly produced car leaves the factory.

Also in Buddhism water represents purity and is an often-used symbol in both traditional landscape and zen gardens. In zen gardens water is, despite their dry appearance, often represented in form of raked gravel or sand to imitate rough seas or the impression of a rushing river.

Water Ripple in zen garden, Kyoto

40

Many mythical creatures of Japanese folklore are described as water creatures. It is even said that the creation of Japan happened from water drops falling from the spear of the Heavenly Gods.

In a more spatial context the water plays a vital role in the urban fabric. Rivers act as recreational corridors out of the busy city. The large rivers are often lined with running and cycling routes, baseball fields or smaller water parks where kids can cool off from the summer heat. On weekends these spaces are especially popular.

During the summer, the waterfronts and river beds act as backdrop to the big Hanabi (fireworks shows), which most cities arrange, a tradition which dates back more than 250 years. The biggest events in Tokyo fill the river banks with more than 500.000 people in attendance. On these occasions the waterfronts function as scenes for the spectators enjoying the show.

With the improving water quality in both the rivers as well as Tokyo Bay new recreational possibilities have emerged; people use the rivers for kayaking as well as fishing and the first swimming beach in Tokyo Bay since the 1960’s opened in 2015 (Hongu, 2013).

Water in the Japanese cities not only provide the people an opportunity to connect with the physical nature, but given the great dependency on water is Japanese culture and religion closely tied together with the presence of water.

Adachi Fireworks Festival along Arakawa River

Fishing in Oyokokawa Water Park in Sumida area

41

River

MEASURES The gradual change from visible water in open rivers to closed systems in the city has slowly changed people’s awareness of the surrounding waters. With every disaster, step by step, a system of hard-engineered structures has emerged, and it is now addressing the challenge of water in an urban setting. The idea of removing water from the cityscape and rerouting it, is rooted in a mind-set of efficiency and control. In a time of climate change, it is a neverending spiral of control, improvement and maintenance. It seems like the more we try to control the water, the greater the damage will be if a structure breaks.

River measures can be divided into two categories. Soft and hard measures. Soft measures cover everything non-physical such as strategies, legislation, information and social structures, whereas hard measures cover the solutions involving construction work; usually physical structures or interventions.

Soft measures In recent years, the focus on soft measures has increased along with the recognition that hard measures might not be sufficient in the current state. Government has required that prefectures publish hazard maps, for the public to know where the risks are and where to evacuate if a disaster happens.

Hard measures Numerous systems of physical structures are currently trying to keep Tokyo safe from flooding. The structures control and direct the water from the mountainous landscapes, through rural sites, into the city of Tokyo to finally reach Tokyo Bay. Snow melting in the mountains and rainy seasons have resulted in the need for very large constructions, to mute the large amounts of water away to the sea.

Different river measures play different roles in controlling the water. Dams act as barriers that keep the water in the rivers. They can also serve as reservoirs to control the amount of water sent downstream and thereby prevent flooding in downstream areas. A less extreme measure against flooding downstream is withholding water upstream in retention basins. These basins cover large areas, that can be filled with water if extra storage volume is needed.

Newer projects aim to combe the retention function with biological and recreational purposes as well.

42

The G-can project To further protect Tokyo, the neighbouring prefecture of Saitama, has taken an extreme measure in the form of the world largest underground water facility. The 6,3 km underground system consists of 5 siloes with connecting pipes, and takes overflow water from five rivers in Tokyo and pumps it into the Edogawa river. The project costed 3 billion US$ and took 20 years to complete (Watertechnology, 2016) It is a great example of how the scarcity of space in Tokyo has led to extreme solutions underground.

G-can project, Kasukabe, Japan

43

Levees Along with the subsidence during the 1960’s and urgent need for protection became evident. The construction of levees along the rivers passing through Tokyo began slowly and as the subsidence increased the levees grew higher. Today the levees act as walls and physical barriers separating people from the surrounding water running through the city. The biggest disadvantage of levees is the risk of breaches; which may happen due to foundation failure, erosion and overtopping. The frequent occurrence of earthquakes makes the levees in Tokyo even more vulnerable. Today, many of the levees need reconstruction or reinforcement, which is both expensive and time-consuming (MLIT, 2016).

Level difference in the 0-Meter Zone

44

Super levee One way of protecting an area against destruction from flooding is by construction of the Japanese concept ‘Super Levee’ invented in the late 80’s. The concept calls for the improvement of the existing levees by making them broader and less steep. This will increase the levees’ resistance to earthquakes, overflow and seepage. A 10-meter high levee should optimally be around 300 meters wide, making it possible to place buildings on top of them. Planned locations for the super levees are along the Sumida River and the Arakawa River, a total length of 30 km, developed in phases of 200-300 meters. In 2012 only 5,4% of the planned work has materialized (Graaf and Hooimeijer, 2008). In a densely structured urban context the construction of 300 meters of levees often involves many landowners, which slows down the process of the redevelopment. The current approach generally replaces all existing house structures with large-scale residential blocks surrounded by parking and open spaces, regardless of the typology being replaced.

Conventional Embankment

Super levee concept

45

River

PROBLEMS Since Tokyo expanded into the lowlands, the region relies heavily on hard flood prevention measures. Initially it was to protect the farmers and their crops, but as the areas developed into a more urban character, the flood prevention became more pronounced, and today millions of people not only in Tokyo but all over Japan rely on these massive structures.

Along with this development, people have gradually become more detached from the water and lost the understanding of the behaviour and dynamics of a river. The general awareness of the risk of living in areas like the former river delta of Tokyo, has disappeared a point made by The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) in a report on prevention against large scale flooding as a reaction to the Joso flood disaster in 2015 (MLIT, 2015).

Relying on a system consisting of a series of individual structures, means the city is only as safe as the weakest structure. If a single element is destroyed, it can have major consequences (a situation which is not entirely inconceivable). It happened when a levee in Joso (Japan) broke in 2015 and most recently in January 2017 when a dam in New Zealand broke caused by a large earthquake.

Dams are very expensive to build and they have a major impact on the river due to the natural flow and processes, the area behind the dam typically gets flooded and may destroy existing habitats. A major risk of relying on dams is the risk of them failing. Thousands of m3 of water is being retained meaning failure would lead to major flash floods downstream.

Expansion and straightening of rivers, as seen with the river Arakawa, create a higher water flow in the river, resulting in a faster discharge. Consequently this increased flow will intensify the erosion of the river banks causing the natural habitats which exist in river bends to be destroyed. Erosion will lead to a higher degree of levee maintenance.

Levees enable artificial ability to inhabit and develop flood plains.

Suddenly large amounts of people and assets are placed in these areas, which state the risk of damage in case of a levee failure. Additionally, levees are obstructing the natural process of sedimentation along the river banks and the level of the river bed will steadily raise and therefore minimizing the overall volume of the river.

46

In the report from 2015, MLIT concluded that 1.200 km. of the total 10.000 km. of riverbanks administered by MLIT were in an insufficient condition (MLIT, 2015). Furthermore, it was concluded that the country shouldn’t rely solely on hard measures, but soft measures should be implemented as well. Such soft measure included a focus on the general lack of public awareness of flood risk and the incoherence between land use and flood prone areas.

In areas situated below the 0-meter mark, the conditions of the levees may be the only thing preventing a major catastrophe.

The high demand of space in Tokyo has led to a series of overand underground solutions with the G-Can Project as the biggest.

Countless of rivers has been rerouted into underground pipes or manmade concrete courses lying dry most of the time. Problems might not be evident right away, but at some point, these structures will be insufficient and water will show on the surface in places not designed for it.

The demand for space has increased along with the expansion of the cities and the accompanying impermeable surfaces. In fact, the needed volume in Arakawa River has doubled since it was constructed in 1924.

According to an official of the Arakawa River Office is it most likely that most of the Tokyo residents are not the least aware of the major risk of flooding threatening Tokyo (ABC, 2014). When citizens do not see the water and its fluctuating level or occasionally experience minor floods, the general preparedness decreases and people forget about the threat. They build and live in a way that does not take the risks into account. The fact that they live in a former river delta where water has been flowing for thousands of years prior to the current urban situation is simply forgotten.

All solutions are expensive, but rather than continuing the current makeshift approach of maintaining, expanding and reinforcing the existing structures, these investments could be used on long term solutions and introduce a more holistic approach where the urban, human and natural environment could be considered as well.

47

River

WORST CASE Flooding is not a new threat, not in Japan nor from a global perspective. People around the world watched in horror how Hurricane Katrina caused more than 50 levee breaches along the coastline, destroying countless houses and leaving more than a thousand of deaths behind. 80% of the city was affected by the flood and FEMA (Federal Emergency Management Agency) estimated the total economic loss to be $125 billion, of which insurance losses accounted for $35 billion. 175.000 insurance claims came from Louisiana alone (FEMA, 2006).

In Japan, flooding has traditionally been a part of an underlying awareness of the Japanese people. In 1910, a major flooding in Tokyo destroyed 270.000 homes, affecting 1,5 million residents and killed 369 persons (De Graaf, 2010). The damage was devastating and the subsequent economic losses reached 4,2% of Japan’s gross national income (in 1910) (Next City, 2013).

Recently in 2015 the typhoon Etau brought enormous amounts of rain to the north-eastern part of the Japanese main island, Honshu, causing several levees along the Kinugawa River to breach. The worst flooding was seen in Jõsõ, a small town of 60.814 inhabitants, where the flood reached as far as 8 km from the breach, and covered 40 km2. (BBC, 2015).

If the levees along the Arakawa were to fail, the government estimates 2000 deaths and 860.000 homeless people. Additionally, 97 metro and train stations would be flooded, paralysing most of the public transport system in Tokyo. The enormous economic consequences are estimated to $322 billion, roughly 2,5 times more than the losses caused by Hurricane Katrina (Bloomberg, 2013).

Tokyo´s Department of Public Works Planning estimate that rebuilding and strengthening the banks of Arakawa and Edogawa to avoid disasters, would cost $15 billion (Bloomberg, 2013).

However, the MLIT expressed in a report from 2015: “We need to share the awareness, across the entire society, that we cannot rely on past experiences, that the anti-flood facilities have their limits … and that we need to be proactive in dealing with disasters” (Otake, 2015) This could indicate a desire for a new way of thinking about flood protection. Something which is highly needed to face the increasingly unknown future.

48

Tokyo, Japan 1910 1679 dwellings destroyed 270.000 dwellings flooded 369 deaths

New Orleans, USA 2005 283.838 dwellings destroyed 73.172 dwellings major damaged 800.000 citizens in need of assistance 1067 deaths

JĹ?sĹ?, Japan 2015 7000 dwellings damage or destroyed 3.000 citizens in need of assistance 7 deaths

Introducing

0-METER ZONE The city of Tokyo is situated in part on a large floodplain, the land where rivers and streams used to flood naturally during certain seasons and weather events. Due to the location on a floodplain, 4 major rivers run through the city; Tamagawa, Sumida, Edogawa and Arakawa.

The 0-Meter Zone is a name describing a specific area of Tokyo which is located below current sea level. Extraction of groundwater to serve factories and a growing number of citizens during the 1950’s and 60’s led to the subsidence of an area almost equivalent to the size of Copenhagen. As the city sunk, the need for protection from the waters surrounding the 0-Meter Zone grew its importance.

Multiple rivers run through these parts of Tokyo, with the Arakawa being the largest. Tall embankments enclose the rivers are and contain the water and protect the city from the fluctuating water level.

Predictions of a rising sea level of 60cm will expand the current 0-meter zone even further. The changing climate will cause more frequent and powerful weather systems, which will add to the existing pressure on the embankment systems which protect the lowlands (JMA, 2012).

50

Current 0-Meter Zone Future 0-Meter Zone Central Tokyo

+60

4,5 largest

cm

sea level rise by 2100

m

accumulated subsidence

84,9

km2

below 0 meter

2.800.000 inhabitants of the lowlands of Tokyo

N 0

1 1,5

3 Km 51

0-Meter Zone

RISK ANALYSIS Three risk analyses will identify the most vulnerable areas of Tokyo City, defining in which, actions of mitigation should be initiated first.

The 0-Meter Zone The area covers 84,9 m2, equivalent to approximately 10% of Tokyo’s 23 special wards. There is no clear number on how many live in this specific zone, but it is estimated that 2,8 million people live in lowlands of Tokyo (Proverbs and Mambretti, 2016). The future 0-Meter Zone is considered to be the current 0-Meter Zone area plus 60cm of elevation, corresponding to prediction of a 60 cm sea level rise.

River improvement areas The river Arakawa runs through the densely populated 0-Meter Zone. The Ministry of Land, Infrastructure, Transport and Tourism has in the Policy of Arakawa River System Improvement pointed out specific sections of the river where extraordinary measures are necessary to ensure the continued safety of the people. Especially along the most southern section of the river a high number of measures are necessary to avoid great economic and human loss.

Furthermore, the shown river section has been designated as a section where “High Standard Embankment Measures” or the socalled super levees, will be put into action (MLIT, 2016).

Combined building risk The Disaster Management Section of Tokyo Metropolitan Government, made a risk analysis of of living in a specific area.

The assessment was made with earthquakes in mind. The map combines several risk analyses including: the risk of building collapses, risk of outbreak and spreading of fire and the difficulty of emergency response. All the analyses add up to a final combined score, and each district is then given a rating from 1-5, with 1 being an area of general low risk, and 5 being a high-risk area in case of an earthquake. The analysis indicates which areas of Tokyo are outdated and in urgent need of redevelopment, in order for them to secure a higher degree of citizen safety in case of a disaster (Tokyo Metropolitan, 2013).

52

0-Meter Zone

RISK ANALYSIS

0 meter zone + 60 cm

Future 0 meter zone

0-Meter Zone

RISK ANALYSIS

Storm Surge Measures Earthquake measures Excavation of channel Emergency river road improvement

River improvement areas

54

0-Meter Zone

RISK ANALYSIS

1 - Low risk 2 3 4 5 - High risk

Building disaster map in relation to earthquakes

0-Meter Zone

RISK ANALYSIS The three risk analyses combined reveal the most vulnerable areas in Tokyo. Within the 0-Meter Zone, several areas along the Arakawa, can be considered unsafe due to insufficient conditions.

Three areas are assessed to be more vulnerable than others; The area of Komatsugawa Hirai, Yahiro and Matsushima.

The combined map shows where the implementation of the vision of Tokyo ShotĹ? should be initiated. The highlighted vulnerable areas need to be addressed to ensure the safety of the citizens.

The transformation of these districts is a potential for upgrading the areas which expectedly will have to change anyway, due to the general condition.

Combined risk analysis 56

0-Meter Zone

DEVELOPMENT APPROACH

Development will be initiated in the defined high risk areas, from where the development can spread to the rest of the 0-Meter Zone.

Development will focus on the core problem, ensuring mitigation of the immediate threats of flooding will made.

2 1

To meet the issues of the declining population, development of the western part of 0-Meter Zone will be carried out before the east, ensuring a coherent city despite potential changes in demand of space.

Of the three identified areas, Komatsugawa Hirai has been chosen as a case for further work.

57

Vision of

TOKYO SHOTŌ The threatening future awaits. Rising sea levels, more frequent typhoons, more powerful rain storms and predictions of an upcoming earthquake of historical magnitude; all will have unimaginable consequences for neighbourhoods such as the 0-Meter Zone; the low-lying area of Tokyo, which in some places is as low as 5 meter below daily water level. Rather than waiting for the catastrophe to occur, it is time to rethink the future of Tokyo’s 0-Meter Zone. A brighter future where water and living is intertwined: A transformation from an impermeable cityscape to an urban archipelago of small islands – ‘The Archipelago of Tokyo’ or Tokyo Shotō.

Tokyo Shotō is a modern interpretation of the historical water city Tokyo used to be. Tokyo Shotō is introducing a more equal and safe relationship between water and city, where life can unfold along with the water.

Tokyo Shotō will be the place where water and city interact and where buildings are based on the ever-changing conditions of the water. Citizens of Tokyo Shotō will be living side-by-side with the water, experience the seasonal and daily changes; they will learn to understand the water and appreciate the recreational as well as the aesthetic value of it.

Taking the steps towards a more resilient future will recognize Tokyo as a foresighted city, which understands the importance of taking the necessary measures to ensure the safety and liveability of its residents; thinking integration rather than separation.

58

Tokyo Shotō

Tokyo Bay

N 0

1

1,5

3

Km 59

60

Arrival to Shin-Hirai by water bus

61

Introducing

KOMATSUGAWA HIRAI Komatsugawa Hirai is the name of an area in the eastern part of Tokyo in the ward of Edogawa, the boundaries are defined by the two rivers of Arakawa and Old Nakagawa to the west. Due to a water level difference in the two rivers, the Old Nakagawa is connected to the Arakawa by a water gate in the south and a pumping station in the north, resulting in a water flow running south to north, opposite of the Arakawa.

Several levees, protects the area against flooding from the rivers.

They function as recreational spaces for promenading, cycling or ball games. The area used to be dominated by industrial structures mixed with low quality housing for the working class, but in recent years undergone a transformation, which has changed the area into a more attractive place for families. Several nurseries, kinder gardens and schools serve the families living here, along with hospitals and daily shopping facilities. two train stations, a variety of bus routes and multiple highways and larger roads are connecting the area to the rest of Tokyo.

Komatsugawa Hirai and the rest of Edogawa have some of the lowest residential land prices in all of Tokyo, which could explain the high number of families living here. In fact, the percentage of families living in Edogawa is well above the average of the rest of Tokyo.

The area consists of two districts - Komatsugawa and Hirai.

A large portion of Komatsugawa has undergone a redevelopment to make room for the construction of the super levee which was completed in 2007. This redeveloped super levee area stands out from the rest of the 0-Meter Zone. Tall fourteen floor apartment buildings dominates the area together with large elevated green spaces doubling as local evacuation areas in case of natural disasters.

Hirai is mostly characterized by low-dense housing, with minor areas of tall slender buildings concentrated near the station.

Most of the major industry has moved, but there are still some factories located near the river and smaller independent companies scattered around northern Hirai.

For the sake of convenience, the two areas will from now on, collectively be mentioned as Hirai.

62

0-Meter-Zone

Hirai

Komatsugawa

3,28 of land

km2

27.750 households

56 600

N 0

1

1,5

3

Km 63

Hirai

HISTORY The area of Hirai consists of several layers of historical functions.

From dense areas of tin plate housing to large scale industry.

It was partially destroyed during WW2, but quickly rebuilt with a focus of industry.

Today parts of the area have undergone large scale development projects, but large areas are still at risk of fire and collapse due to the heritage of the old dense districts.

Several attempts have been made to mitigate the, like creating better access for emergency vehicles or replacing old housing with large fire resistant buildings.

The southern part has undergone a major redevelopment as a part of the super levee project. This has removed all prior housing and replaced it with high rise buildings and apartment blocks on elevated ground.

Industrial activity dominating the southern part of Hirai, 1968

64

Levee and factories, 1976

1979

1963

1936

1947

1992

N

65

Hirai

HISTORY 1930 River adjacent area unbuilt Scarcely built

1936 Narrow levee Industrial activity along river Area of high density housing

1948 Industry intensified Empty lots after WW2 bombings

1963 Increasing industrial concentration Land fill of harbour area General densification

66

1979 River lock replaced by pumping station Removal of industry Housing on reclaimed land Expansion of levee Establishment of recreational areas

1984 Establishment of park and fire cisterns Densification of existing housing

1992 Establishment of river park Transformation of industry to housing

2015 Improvement of infrastructure and disaster access Housing renewal Transformation of industry to housing Improvement of green areas 67 along waterfront

Hirai

HISTORIC WATER Wetland

Loading or drainage channels

Loading or drainage channels

Loading or drainage channels

Present water areas Historical water areas as of 1936

68

0

125 250

500

Meters

Arakawa - May rain, Kawase Hasui (1932)

69

Hirai

PRESENT

Arakawa Old Nakagawa

N 0 70

125 250

500

Meters

Pumping station

Hirai

TERRAIN

Railway

Super levee

Evacuation area

N 0 Water lock

125 250

500

Meters 71

Hirai

CHARACTER

Densities

Narrow streets

Water relationship

Functions 72

Current state

Levee living

73

Hirai

ROAD STRUCTURES

t)

0 74

125 250

500

Meters

Road structure affected by old river course.

Dense old structure

Restructured neighbourhood in strict grid structure

Large scale structure old industrial grounds

75

Hirai

INFRASTRUCTURE T

T

Towards Edogawa

Towards Central Tokyo

M

M

Metro and trainline Connecting roads Elevated highway 76

0

125 250

500

Meters

Elevated railway tracks cutting though the city

Elevated highway with few exits in Hirai

Elevated highway without exits in Hirai

Elevated metro tracks connecting Hirai to Tokyo.

77

Hirai

CULTURAL VALUES

2

1

3

4

6

5

11 9 7

12 13

8 10

14

15 Buddist temple Shinto shrine Preservable structures 78

0

125 250

500

Meters

1

4

7

10

13

2

3

5

6

8

9

11

12

14

15

79

Hirai

LAND USE

Industry Residential Commercial district Residential and commercial Residential and light industry

0 80

125 250

500

Meters

Heavy industry in the center of the city

Densely built residential area with recently constructed firebreak road

Shopping district in around Hirai station

Small shops and housing side by side in an adjacent to the commercial area

Area of mixed use Residential and industry

81

Introducing

SHIN-HIRAI Shin-Hirai (‘New Hirai’) is the first step towards the realization of Tokyo Shotō. It will consist of multiple islands designed to activate the water surface as an equal urban element with the rest of the urban fabric. The water will be used for both, living, transportation, sports or a tranquil moment in the hectic megacity.

The city will be organized in two main centres located around the existing stations with multiple local centres. The island forms will be based on existing physical structures such as landscape, religious locations and infrastructure.

To ensure a resilient community terrain and city are going to be integrated, meaning different housing typologies will be required depending on the elevation of a specific area.

Between the islands the water will be flowing freely, framing each island with a variety of functions and experiences. The whole area will be tied together by a recreational belt giving equal access to both green and blue qualities across the area.

Water is a vital element of Japanese culture. Adding it to the city will not only have a disarming effect on the risk of flooding, but also activate the water on both a functional, aesthetic and spiritual level.

Living with water is both a more safe and beautiful way to live.

82

Floating houses

Temporary levee

Commercial Station

Floating houses

Recreational island

To Central Tokyo

Industrial/business

Recreational island Temporary levee

Temporary housing

Commercial Station

N

Water bus

0

125

250 Meters

83

Shin-Hirai

WATER & LIVING Main design objective In order to achieve a stronger integration between the water and the city, it is important to activate this otherwise unused surface. The water surface will become a strong asset in Shin-Hirai functioning as a multifunctional medium for flood risk mitigation along with recreational, residential and for transportation purposes.

Activating Water Other design objectives In addition to the main objective of activating the water, three other objectives have been identified, which should be included in the considerations of a future design for Tokyo.

Creating a robust future city adaptable to the declining population requires an attention to how to utilize the decreasing demand of space. By reducing the existing habitable area of the city, it is possible to maintain a dense urban character in the areas concentrated around the functional centres.

Declining population

Future Tokyo is looking old. The increasing amount of elderly people requires new structural and functional demands for the city, such as age friendly housing, retirement homes and a high level of accessibility. A compact city with short distances and a pleasant recreational environment is not only beneficial for elderly people, but will increase the overall liveability of the city.

Ageing population

The changing climate requires an alternative focus of the city.

Increasing sea levels will change how to live in low-lying areas.

Increased precipitation demands a softer city with less sealed surfaces. Additionally, to mitigate the effect of urban heat island more areas of water and vegetation is required.

Climate Change

84

A morning commute by water bus in Tokyo ShotĹ?

85

Shin-Hirai

ISLAND FOUNDATION For the basis of the design of the islands, 3 principles were applied.

First, a wish to give to release the water to flow freely in the area.

Second, a protection of undeveloped hinterland is necessary to be able to keep the neighbouring areas safe in the process of realizing Tokyo ShotĹ?. Finally, spatial analyses are applied to root the design to the specific location.

The existing levee along the Arakawa will be transformed into islands, still providing an efficient flow in the river, while allowing the water to flow freely between the islands. The islands have been formed to prevent still-standing water, keeping the fresh water environment healthy.

Vision design principle

+

Free flowing water 86

Protection of hinterland

For the protection of the hinterland, a series of continuous islands is formed along the existing river. This continuous stretch of terrain will be broken down into smaller islands, once the neighbouring areas are fully developed.

To root the island design to the specific site, a series of analyses were made, mapping out the historical and cultural values of the area. The locations of existing temples, shrines as well as stations have been the basis for where to form the solid surfaces, while the analysis of both terrain and historical water bodies have defined the basis of the liquid structure.

Road structures from the existing Hirai have defined the islands’ forms as well as future road structures.

Analysis conclusion

+

Island foundation

=

Important structures to consider in the formation of the islands

Final island design 87

Shin-Hirai

LAYERS The development of Shin-Hirai builds on the overall structure of Tokyo focusing on multiple centres concentrated around infrastructural nodes. This will support local development and a strong sense of local mobility securing a highly accessible and friendly environment for elderly citizens as well as people relying on public transport or bicycles. By carefully structuring the area, the residents are offered a high-quality city with plenty of areas for activity and recreation.

The following diagrams presents an overview and will be elaborated further.

Gradient Housing

88

Land use

Local center structure

Waterscapes

Recreational

Transport

Terrain

89

Shin-Hirai

GRADIENT HOUSING Gradient housing is an expression for an approach to context specific building typologies and could be a way of living in coexistence with the water. Gradient housing consists of 2 overall categories: dynamic and static housing.

Dynamic housing is a typology where the individual house follows the water level as it rises and falls. It can either float or be placed on solid ground in everyday situations and float when the water exceeds a certain level.

This way, the water surface will be included as an integrated urban surface, to be enjoyed by the citizens.

Static housing is built in a predefined safety level. It may consist of both regular houses built directly on the ground and houses built on pillars in water or in areas at risk of being flooded. The important thing about static housing is that they are only allowed to be built with a minimum floor level consistent with the safety level.

By building the future water cities following these principles, there would be no need for large constructions separating the water and the cities instead the security is incorporated as a part of the individual building. Inhabitants will be able to regain the lost relationship with the water. Their houses will rise and fall with water and recreational access to the water will be an integrated part of everyday life.

Regular

Amphibious

Elevated

Floating

90

Dynamic

Static

Dynamic

Static

Water levels Safety Level Expected max. level Daily fluctuation Static and dynamic housing - Everyday situation

Safety Level Expected max. level Daily fluctuation Static and dynamic housing - High water

91

Shin-Hirai

GRADIENT HOUSING

Floating Houses In floating neighbourhoods, the water acts both as the surface for transportation and for recreation. One will have direct access to the water and learning about the dynamics by living side by side with it.

The focus in Shin-Hirai will primarily be on residential functions, including smaller everyday services such as convenience stores, izakayas (Japanese pub) and restaurants. It could also be used for commercial and business functions in other areas.

Floating houses are always levelled with the water. They can be singular or attached to each other. They are moored to large posts which allow the houses to rise and fall with the changing water levels but holding them in place.

The houses are attached to shore and each other by floating walkways which act as lines for utilities as well.

In case of earthquakes the water surface is the safest place to be.

The water will absorb the vibrations a the only places to include earthquake measure are for the mooring posts and connection points to the shore.

Floating neighbourhoods are placed in areas of calm water sheltered from intense water flows. Micro islands will function as attachment points for the neighbourhoods as well as shelter from the stream and offer a variation of natural views from the houses.

Entrance

Mooring post

Platform

Connecting board-walk

Connecting to land. Life in between the houses

92

Massbommel, Holland Directly on the water, with own boat parking space

Ijburg, Holland Neighbourhood of floating houses with different architecturetural expressions

Boat parking

Ijburg, Holland Small spaces in between the houses Principle section 1:300

93

Shin-Hirai

GRADIENT HOUSING

Elevated housing Elevated housing consists of regular buildings extended on pillars, they can either be built on water or on land. The elevated ground floor will have a minimum level similar to the overall safety level, making it on par with the regular parts of the city. When the regular housing typology is extended onto the water, a gap between house and water will emerge and create new opportunities. This space can be designed with jetties, and thereby used as recreational areas or just kept as a blank water surface creating a semi private area for activities or mooring of commuter boats.

Elevated housing can be placed anywhere with low rate of water flow. Ideally, this typology is used in areas with an abrupt transition from land to water, like in areas with quay edges; continuing the urban character onto the water surface.

Entrance

Floating board-walk

Connection to land. Life in between the houses.

94

Itsukushima, Japan Elevated temple preserved for varying water levels

Copenhagen, Denmark Elevated houses with semi-private static platforms

Ine no Funaya, Japan Elevated houses with boat garages Principle section 1:300

95

Shin-Hirai

GRADIENT HOUSING

Amphibious housing Amphibious housing is a typology of houses built on land but instead of being permanently fixed to the ground they are built on a buoyant foundation resting on the ground, making them flexible towards varying water levels. When the water rises, the building will float. It is attached to mooring posts like the floating houses to keep it in place.

Built with buoyant foundation means it will either be resting on the ground or be integrated in the terrain. This makes it most suitable for sloping terrain; utilizing the terrain to absorb the gap between entry level and the bottom of the foundation. Being built as a waterfront typology gives direct access from the house to the water.

Amphibious housing is placed on shorelines without direct water flow. Occupancy of the shoreline means it is most suitable for mainly residential areas, where the prioritization of public access to the shoreline is low.

Mooring post Buoyant foundation Changing water level

Amphibious housing with a water view

96

Massbommel, Holland Situated on land, reaching out over the water

Massbommel, Holland High water level situation

Recreational path

Marlow, United Kingdom Integrated in the terrain, with a close proximity to the water Principle section 1:300

97

Shin-Hirai

LAND USE To ensure a functional city of high-quality, the area is categorized into different classifications of land use inspired by the Japanese classifications along with the aim to comply with the overall design objectives.

98

Residential Primary residential area. Small local shops and restaurants allowed.

100% Residential

Nature

100% Nature/Recreational

The areas provide various natural experiences within the city. On the bigger nature islands, large scale sports facilities such as baseball, football and driving ranges for golf is allowed.

The micro islands are preserved for unspoilt habitats, and are only accessible from water or through the floating neighbourhoods connected to them.

Commercial Centralized functions focused around the two stations. The commercial areas include both businesses and residential and have a dense urban character.

50% Residential 50% Commercial

Neighbourhood Commercial

75% Residential 25% Commercial/Service Functions

Local centre with everyday functions; local transport hubs, grocery stores, schools and institutions, health care facilities as well as recreational hot spots. To minimize traveling distance for the elderly citizens, especially senior friendly housing and functions will be in proximity of areas classified as neighbourhood commercial.

Industrial

Area for large scale purposes such as and company domiciles, storage and non-polluting production facilities.

100% Business/Industrial 99

Shin-Hirai

CENTER STRUCTURE The functional hierarchy of the area is structured in two levels.

Two main centers concentrated around the stations to ensure the general availability of functions, and several local centres for everyday necessities.

100

Clothing Store

Apartment Office

Bank Train Station

Restaurant Office

Supermarket

Major Centre The major centres are structured as mixed use; with the availability of commercial, residential and service functions. They function as the main gateway to and from the area by train or metro; creating easy access to jobs internally and externally.

Retirement Home Convenience Store

Restaurant

Apartment

Community Center Apartment

Water Bus

Local Centre The local centres function as local gathering points for the citizens and offer the basic everyday necessities and recreational possibilities at the hot spots. To accommodate the increasing amount of elderly people most functions addressed to them is concentrated in these areas, such as grocery shopping, public services or social activities.

The local centres also function as transportation hubs connecting to major or other local centres by either water based or land based public transportation.

101

Shin-Hirai

RECREATIONAL Recreational areas on land and water alike are important parts of Shin-Hirai. They add quality to the neighbourhoods and encourage activity, connects the islands and activate locations internally. Two main subjects define the framework; the recreational corridor and the recreational hot spots.

The recreational corridor ties the northern and southern part of Shin-Hirai together and make it accessible from most islands.

Through its landscape, the corridor connects neighbourhood roads, city park and the recreational islands, ensuring a variety of benefits such as lowering the urban heat island effect and adding to the overall aesthetics. A continuous path through the corridor, will function as a guide through a variety of different landscapes, while creating a safe path for everyone to use for daily activities or leisure.

The recreational hot spots are collections of land and water activities, placed to support the local centre structure. They are placed in proximity to shrines and temples with access to public transport.

The hot spots are where people are naturally concentrated, where neighbours meet randomly or by appointment. These anchor points strengthen the sense of local enthusiasm and community feeling.

The recreational hot spots can be realized as plazas, harbour baths, or various public sports facilities They can either exist as single elements or in combination, depending on the specific needs and location.

Recreational corridor Recreational hot spots

102

SPORTS Outdoor sports are, as in other countries, very popular. Providing outdoor sports facilities encourage an active and healthy lifestyle. Implementing outdoor sports areas to be used by schools and residents is vital for a high-quality neighbourhood.

The most popular sports in Japan include baseball, tennis, golf, football and swimming. Some of them can be implemented in the recreational corridor, others in the recreational hot spots depending on the spatial requirements.

NATURE The recreational nature is for activities taking place in green, less programmed surroundings – a vital element of ShinHirai. The soft sloping edges allow people to access the water for activities such as fishing, rowing or swimming.

EVENTS Celebrating events is an important part of the Japanese culture, which the recreational landscapes of Shin-Hirai must be able to support.

One of several important events is the annual fireworks festival, which requires large open spaces along the waterfront. Another important event is the flower viewing festivals, primarily during the cherry blossom season, accompanied with picnic in the parks along with friends and family. Matsuri are the festivals arranged by local shrines in open public spaces such as parks, streets or plazas. They are all contributing to bringing together the community of Shin-Hirai.

URBAN Recreational urban areas are for informal activities, mainly in the urban environment.

These areas provide promenades along the water front combined with green areas of an urban character. Wooden decks allow people to access the water, whether it’s for relaxation or for a swim.

103

Shin-Hirai

WATERSCAPES Having spaces of different scales in a city is important to how one experiences it. Small scale spaces provide different programming and atmospheres than large scale spaces. Integrating the water surface as an element on par with urban spaces creates the possibility to look at the waterscape in a similar way as one would with the urban landscape.

By classifying the waterscape with the well-known S, M, L and XL classifications, it is juxtaposed along with urban space.

The layout of the solid landscape of Shin-Hirai is designed in a way that all 4 classifications are at play and individuals will be able to move through spaces of different sizes, depending on their means of transport. The experience of the 4 is different and can vary from being by the shore to be out on the open water.

104

S Small is defined as waterscapes moving through the solid landscape of the islands. They could be small channels along roads or open water features between houses acting as a common space similar to historical backyards centred around the well.

M Medium is characterized by intimate waterscapes between buildings along or on water.

They can be compared to a small residential road, a space to greet your neighbour, informal water activities or a quiet moment on your private jetty.

L Large waterscapes are defined by open water surfaces where water transport as well as water sports along the shores are possible. They offer a wide view and are primarily found between the islands.

XL

XL is the large open surface areas.

They provide space for “large scale� transport and a high water flow rate. XL waterscapes are spaces such as the Arakawa and large harbour areas.

105

Shin-Hirai

TRANSPORT The transportation layout is designed with the focus on soft traffic users; pedestrians and bicyclists. The recreational belt functions as the connective backbone for these users. Car traffic is linked to existing through-going roads.

106

Water transport Water transport in the form of public river buses and small private boats will contribute to the overall activation of the water surface. Water bus stops will be placed in the local center areas for convenient access and to ensure coherence with other means of public transport.

Pedestrian and bike paths Shin-Hirai is designed with a focus on pedestrians and bicyclists. All islands will be connected, by bridges for either all types of traffic or with the priority of only pedestrians and bicyclists. Access to the recreational islands is restricted to pedestrians, bicyclists and emergency vehicles. The existing continuous path along the river is rerouted as the soft traffic backbone in the area giving seamless access to the two major centres.

Existing car roads The existing main roads connecting the area to the rest of Tokyo are kept, and linked with new road systems matching the new situation. The road connection crossing the area from east to west will thereby be preserved and integrated.

Existing connections The layout of the metro and train is already elevated above 0 meter, it is therefore not necessary to reconstruct these, ensuring an unchanged situation on the existing lines. The area of Shin-Hirai will be well connected both internally and externally by roads and several forms of public transport.

107

Shin-Hirai

TERRAIN The realization of a future archipelago requires considerations of how to; prevent local flooding within the islands, principles for how the islands will be constructed most efficiently and to make sure the design is prepared for the future of changing climate.

108

Integrated safety level

Daily level fluctuation +/- 11 cm

Expected max level* +73 cm

Proposed safety level* +150 cm

The everyday water level of Tokyo Shotō will be fluctuating with the natural cycle of high tides and low tides in Tokyo Bay along with the influences of seasonal changes.

The proposed safety level for the islands in Tokyo Shotō will protect the citizens from future sea level rises, storm surge and other changes in the water level. This level is based on the design standards of MLIT which is grounded in previous storm surge and flood events. Due to MLIT’s retrospective approach the proposed level is designed with a large safety buffer to ensure the safety of the generations to come. *These numbers may be redefined based on future changes in major predictions for climate changes or technology improvements.

Flood repellent The islands are designed with an inclining terrain, with the highest elevation on the middle sloping slightly towards the water. This makes water run off the islands and into the river during heavy rain thus avoiding accumulation of water in landscape depressions.

Island construction Current ground level

+ Shotō

The islands will be created by redistributing soil from areas that will be covered by water in the future.

The construction method will vary from site to site depending on geology, future water flow and the desired transition from land to water. Reforming the land will take place before the water is let into the area, to enable for a more convenient construction phase. Excavated soil from adjacent river improvement projects could be used as fill for the island bodies.

109

110

Everyday situation in a floating neighbourhood bordering a commercial area

111

Shin-Hirai

STAKEHOLDERS

Public transport companies Sports clubs Local commercial interests Businesses Religious communities 112

0

125 250

500

Meters

Shin-Hirai

STAKEHOLDERS The government will be carrying out the project in close cooperation with local governments as well as other public bodies of relevance.

To ensure a high quality and successful realization of the vision, it is important to include non-public bodies as well, such as the affected citizens and stakeholders of the area. Generally, for the area of Tokyo Shotō the group of stakeholders consists of individual people, businesses, organizations and others who may be affected by the changes happening in the area. It is very important that the project is carried out with a great sense of transparency and cooperation since a lot of people will be affected.

The process of involvement should first of all focus on clarifying to the stakeholder, why the changes are necessary and then on the needs and wishes of the stakeholders.

The local knowledge should be collected and applied in the process.

The cooperation with the listed groups of stakeholders is key to ensure a smooth implementation of the future city. For a more detailed level, further studies are needed to lay out the organizational structure for the project.

anie s ses

pan i

m s Co gou i l e R

Tokyo Shotō

NG O’s

lubs

Res

ide n

ts

Shin-Hirai

ities

mun

rts C Spo

ce mer om C f o ncil Cou

Uti lity Co m

mp t co por ine s

es

ans

r lic T Pub Bus

Examples of non-public stakeholders

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Shin-Hirai

WATER The water level of Arakawa fluctuates a lot, depending on time a day and season. A large volume of water passing through a smaller space causes a lot of pressure on the levees, resulting in risky situations. Due to the increased overall capacity of Tokyo Shotō, the suggested water level will be more stable, mitigating future flood risk.

The proposed water levels are based on a general assumption, of which the existing volume of water will be distributed to the future area of Tokyo Shotō. Further calculations are necessary for future concretization of the project, to ensure reliable information about water flow, levels etc.

Due to a variety of factors such as unsecure climate forecasts, general calculations etc. it is hard to determine the accurate event the area is designed for. However, the proposed safety level is suggested to cover a doubling of the expected maximum level already defined by MLIT. Should these factors change during the concretization of Tokyo Shotō, the water levels can be adapted to the new scenario.

0-Meter Zone

Tokyo Shotō

Water area: 600 ha

Water area: 5400 ha

Expected max level

7 6

6

5

5

4

4

3

3

2

Proposed safety level Expected max level

1

Daily water fluctuation

0

+/-1,25m

Daily water fluctuation

2 1 0

-1

-1

-2

-2

Current water level situation

114

7

6,5m

1,5m 0,73m +/- 0,11m

Tokyo Shotō water level situation

Shin-Hirai

NUMBERS OF LIVING Focus will be on transforming the landscape of Hirai to the future waterscape of Shin-Hirai. To meet the overall decrease of the population in Tokyo, Shin-Hirai will be designed for a lower concentration of people giving space to the water. With the increase of water surface and the decrease of population number it is possible to ensure a higher amount of square meters for the future citizens.

The calculations assume each citizen takes up 50 m2 including residence and necessary square meters adjacent to it; parking, pavement and street.

3,28 of land

km2

0

km2 of water

Shin-Hirai

2,14 of islands

km2

1,14 of water

km2

58

m2 /capita

56.600

Hirai

on land

68

m2 /capita

31.500 on land and water

115

Shin-Hirai

DEVELOPMENT PHASING The overall phasing concept of Shin-Hirai will serve as inspiration for the overall development of Tokyo Shotō, though it is still important to look at the specific local context of each area.

A During the construction of the resident’s new homes, newly established housing in the southern part of Shin-Hirai will serve as their temporary homes. These temporary homes will initially be built on land as regular housing, but as the area expands, there will be room for floating housing as well.

116

B Next, the making of islands may begin.

If there are buildings of cultural value, they are carefully taken down and stored before the construction. Excess soil from other adjacent projects, such as nearby river excavations, will be imported and used as basis for the first islands.

C

D

In the process of forming Tokyo Shotō it is important to keep the rest of the lowland safe; to do so, some of the islands will be created as temporary levees. Later, when the adjacent areas are developed these islands can be separated allowing water to flow freely to the next area.

When the construction of an area is finished, the residents can move back into their area of newly built housing.

In most cases, the residents will be compensated with a similar piece of land/water as they moved from, otherwise they will be economically compensated.

2

3

5

4

1

N

117

Shin-Hirai

DEVELOPMENT PHASING The first stage of construction includes two, mainly residential, islands; one industry island and one recreational island. The area already consists of an area of terrain meets the safety standard.

Here, the existing houses; station and functions will be preserved.

This is also where the temporary housing will be built in the existing open area. By establishing a place for industry and light production, existing companies in Shin-Hirai can move their business’ in the early stages, making the transformation of the next phases less cumbersome. The early establishing of the recreational island, will result in a more settled nature to enjoy, when Shin-Hirai is fully complete. The islands of phase one will be connected to the established car roads in the south with and bike/pedestrian paths on the temporary levees between the islands. In the end the existing levee is opened up and water is let into the area.

1

118

The second stage of construction includes two, mainly residential, islands. Floating houses are being establish in the area of the previous wetland. The regulating water lock is preserved until Shin-Hirai is finished and the hinterlands are raised to the safety level. The terrain of the small island in the north already meets the safety standard, which means that the existing houses can be preserved. The residents of the other areas will move to the temporary housing area and the existing industry will move to their new location on the industrial island. The residents will be able move back when the construction is finished. The temporary levee is established and connected via paths to the existing levee. The islands of phase two will be connected to the established car roads in the north with bike and pedestrian paths on the temporary and existing levees that will connect the north and south. In the end, the existing levee is opened up and water is let into the area.

2

119

Shin-Hirai

DEVELOPMENT PHASING The third state includes two, mainly residential, islands and one recreational island. The residents will move to the temporary housing area until the construction is finished. The creation of the recreational island will bind the area together with a recreational path whilst serving as a destination for outdoor activities. In addition, the islands of phase three will be connected to the established roads now joining the northern and southern islands. In the end, the existing levee is opened up and water is let into the area.

3

120

The fourth stage includes two residential islands. The residents will moved to the area of temporary housing until the construction is finished. The two islands latch onto existing bridges in the east; connecting them to the rest of Tokyo, as well as a north/south car road running through the area creating the possibility for the first time to circulate Shin-Hirai. In the end, the existing levee is opened and water is let into the area.

4

121

Shin-Hirai

DEVELOPMENT PHASING The fifth stage includes one residential island and one commercial island. The residents will move to the area of temporary housing until the construction is finished. The businesses will either move permanently or temporary to the local centre areas now established in Shin-Hirai. During construction, the station will be temporarily be out of function. The islands of phase five will be connected to the established bridges in the west, by bridges between the islands and with bike and pedestrian bridges to the recreational island. In the end, the existing levee is opened up and water is let into the area.

5

122

When the neighbouring areas are fully developed, the rest of the temporary levees can be removed, from which the soil can be used for islands outside Shin-Hirai. When ready, the northern and southern lock gate can be removed and the water will be able to flow freely.

6

123

Outro

DISCUSSION For many years, there has been a tendency to claim the right to live wherever we want. It seems that just because a piece of land is habitable we should occupy it.

With the rising issue of climate change and the challenges it brings, it is time to reassess how we build and rebuild our cities. Could this approach reflect the underlying landscape better, and could it be a way to mitigate the current and future threats from natural disasters?

All cities are characterized by a high degree of complexity. They consist of layers upon layers of changing demands and functions through times. New functions must be fitted in with the existing context, defined by previous use. The cities have become a matrix of compromises. To be able to transform these cities to the future it might be necessary to cut away layers of the past and partly start from a clean slate. Humans have traditionally been flexible and tried to adapt to the changing conditions of the natural landscape, but we have in modern time come to a point where civilization defines the conditions which nature is expected to adapt to.

Tokyo has been through natural disasters and WWII bombings and on several occasions, the citizens of Tokyo have been forced to start from scratch. Often, this caused an acute need for housing and resulted in large hurried developments. By restarting voluntarily and taking a more holistic approach, similar situations could be avoided, enabling the city to control the process and gradually grow into the robust, liveable and harmonious city Tokyo is supposed to be.

The proposed vision focuses on the threats of flooding, but considering the global challenges we are facing, like hyper urbanization caused by for example environmental migrations, the approach of how to integrate nature and city, could be converted to other situations to enable urban development with a landscape contextual awareness.

By deviating from the fixed conventions of the city and the status quo of perceiving them as permanent unities, we can face a future, where nature is better integrated in our lives, both in terms of quality of life and as a mitigation of climate threats.

Rather than fighting nature the future city could adapt to the conditions of nature.

May the end justify the means?

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Outro

REFLECTIONS The objective was to form a vision of how an alternative future of life in the 0-Meter Zone could unfold. We saw an existing approach of stop gap measures based on previous events, rather than a comprehensive foresighted vision and found it incredible that this many people live with the imminent threat from flooding every day.

The vision describes a transformation of an area of purely urban priorities to an area where both urban functions and leisure are combined while also prioritizing nature. Other priorities could have been made, like excluding all urban functions and letting the water reclaim the landscape, but considering the density and complexity of Tokyo this seemed unreasonable.

During the working process several challenges were identified, including that of project economics and soil redistribution. In order not to lose sight of the greater concept some of these challenges had to be toned down.

The focus has been to develop an overall vision for a specific location serving as an example of such a balanced structure. This has been done based on a set of design concepts, which can be used as a general approach. Given the choice of this approach, further detailed analyses would have to be made to breathe life into the vision.

We are aware, that the vision in its current form may raise just as many questions as answers, but our goal has been to express an entirely different perspective and hopefully ignite a discussion of how future cities can be structured to better balance the needs of the inhabitants against the physical natural context including changing climatic conditions.

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Project

REFERENCES Literature Brumann, C., Schulz, E., (2012) Urban Spaces In Japan, 1st ed. London: Routledge (Arakawa catchment area, length of Arakawa, number of people in catchment)

Bureau of Urban Development, Tokyo Metropolitan Government (2013) The Seventh Community Earthquake Risk Assessment Study FEMA (2006) Summary Report on Building Performance, FEMA 548 /April 2006 Gotoh, H., Oshiki, H., Maeno Y., Takezawa T. (2011) Measures and residents’ attitudes at flooding in Tokyo lowland of Japan, in F.C.B. Mascarenhas, Flood Prevention and Remediation, WITpress (m2 of 0-Meter Zone and accumulated subsidence)

Graaf, Rutger De and Fransje Hooimeijer (2008) Urban Water In Japan. 1st ed. London: Taylor & Francis Group, pp. 122 – 139 Japan Meteorological Agency, Ministry of Environment, Ministry of Education, Culture, Sports, Science and Technology (2012) Climate Change and Its Impact in Japan, Japan Weather Association (Climate Change; Sea level rise, Rising temperatures, disaster predictions)

Ministry of Land, Infrastructure and Transport (2003) Introduction of Urban Land Use Planning System in Japan, January 2003 Ministry of Land, Infrastructure, Transport and Tourism (2016) Arakawa River Improvements, Kanto Regional Development Bureau (River improvement area, area in m2 and population)

Muramatsu, M., Akiyama, H. (2011) Japan: Super-Aging Society Preparing for the Future, The Gerontologist, Vol. 51, No. 4, Oxford University Press, pp. 425–432 OECD (2015) Ageing in Cities - Policy Highlights, OECD report Proverbs D., Mambretti. S. (2016) Urban Water Systems & Floods, Volumen 165, WIT press Proverbs D., Mambretti. S., Brebbia, C., Ursino, N. (2016) Urban Water Systems & Floods, WIT Transactions on the Built Environment (Population in the lowlands)

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Image credits Unless stated otherwise, image copyrights belong to: © Mie Dehlsen © Andreas Faartoft P. 31 - © Utagawa Hiroshige P. 33 - Unknown, downloaded from: http:// www.automobiles-japonaises.com/HistoireAJ/ Hearthquakes/1923KantoEarthquake.php [16 Jan 2017] P. 35 – Unknown, downloaded from: http://www. japantimes.co.jp/wp-content/uploads/2013/01/ fl20120320a1a.jpg [12 Feb 2017] P. 41 – © dru/HinoMaple P. 47 – © Steve Sundberg P. 47 – © Justin Sullivan P. 47 – © Wikimedia Commons P. 47 – © Reuters P. 60 – © City of Edogawa P. 64 – © Kawase Hasui P. 68, 69, 71, 73, 75, 77, 103 – © Google Maps (Streetview) P. 68 – © MHS Planners P. 75 - Unknown, downloaded from: http://www.tesshow. jp/edogawa/temple_hirai_zentsu.shtml P. 91 – © Adam Mørk P. 91 – Unknown, downloaded from: http://static. panoramio.com/photos/original/121639709.jpg P. 93 – © Baca Homes P. 103 – © Dissing+Weitling P. 103 – © Tokyo Cruise

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