Daiki Mabuchi - Reverse

Reverse Transformation of Urban River Public Space in Tokyo

Daiki Mabuchi Master Landscape

Daiki Mabuchi

daikimabuchi89@gmail.com

Master Landscape Architecture Academy of Architecture Amsterdam

November 2023

Committee

Marieke Timmermans (mentor)

Yttje Feddes

Hiroki Matsuura

Expert Yuka Yoshida

Exam Committee

Jana Crepon

Philippe Allignet

Introduction

Motivation

Japan, where I came from, is an island country, and therefore, Japan has a rich water landscape. Even though there are many water surfaces in the country, many waterfront spaces are not designed for people to use.

In general, most waterfronts in Japan are covered by concrete walls to protect the land from water disasters, and I do not see many places that consider people’s use. This is because civil engineering still prioritises designing and making a waterfront space, and landscape designers do not involve it so much. The seawalls along the coastline of the Tohoku region (northern part of Japan) are recent examples.

The concrete wall in the picture was made after the 2011 Tohoku earthquake and tsunami in Kesennuma city Miyagi prefecture, near my hometown. Also, my father is a civil engineer who was involved in this project, and my father and I went to see those huge flood wall / dike projects when I went back to my hometown. At this time, I was a landscape architecture student at a university around Tokyo, and every time I went to that area, I saw the coastline was replaced by a massive concrete wall or dike.

If landscape architecture had been more involved, the situation would have improved. As a landscape architecture student, I have wondered about this conventional Japanese way of water protection. I wanted to create a waterfront space where people can appreciate the water in Japan. This was the big motivation why I came to the Netherlands to learn how people live with the water. As a final project for the academy, I tackled how the waterfront in Tokyo could be improved in the future.

Seawall in Kesennuma city, 9.8m + ( date: 29 December 2020 )

Water disasters and Concrete Walls

On March 11, 2011, Japan experienced the strongest earthquake in its recorded history. The Tohoku earthquake caused a tsunami. The Tohoku tsunami produced waves over 10 meters high, it braked dikes and many towns along the coastline were damaged by the tsunami. More than 450,000 people became homeless, and over 22000 people died as a result of the tsunami.

After the disaster, massive concrete walls or dikes were created as tsunami protection walls along the coastline of the Tohoku region. However, those seawalls block not only the tsunami but also a view of the sea. The relationship between the sea and the mountains was disconnected, and many residents moved elsewhere.

Earthquake and Tsunami in 11 March 2011 (22200 people dead)

Tsunami on March 11, 2011

Ofunato city seawall 7.5m+ high

Koizumi Beach costal levee 14.7m+ high, 90 m width

Rikuzentakata seawall, 12.5m+ high

Sumida River in Tokyo

The situation of the waterfront in Tokyo is the same. The Sumida River, one of the huge rivers that flow next to the city centre, is covered by a flood wall, and water cannot be seen from a street. Of course, protecting people from a flood is the most important thing, but improving the quality of the waterfront public space is also important to increase the liveness and quality of life in the city. I believe the balance between flood protection and public space quality is important to make a well-used waterfront space in Tokyo. This project aims to reconnect people to the water in the capital of Tokyo by changing the river public space and its network.

Research

Location: The Sumida River in Tokyo

Tokyo is situated in the delta of Kanto Plein. Because of this topological situation, Tokyo has many rivers, canals and harbours. The Sumida River, one of the huge rivers in Tokyo, flows next to the metropolitan area of Tokyo. For my graduation project, I would focus on the Sumida River because it has played an essential role for a long time, both culturally and functionally, and the river represents Tokyo as a city river.

Topographic situation

The Sumida River is a part of the Arakawa River system, which is 173 km long and has a height difference of 1,500 m. The Arakawa River system has a 3,000 km2 water basin covering Tokyo and Saitama prefecture. At the lower part of the river, it splits into two parts: the Sumida River and the Arakawa River. Due to the fact that the Sumida River flows through the delta area, its water level is constantly changing with the tides.

Also, the ground level of the eastern part of Tokyo is lower than that of the west side because it was originally a floodplain of the river. Furthermore, the ground sank below sea level because of pumping a large amount of groundwater for industrial use in history. Therefore, the eastern part of the Sumida River has a significant flood risk if the water overflows.

River Basins area : 2,940km2

River Length : 173.0km

Sumida river

Arakawa river

Edogawa river

Topographic map around Tokyo

Topographic map around the Arakawa River systrem

Flood risk of the Sumida River

The Sumida River has been facing two significant flood risks. One is flooding after heavy rain in an upper stream from Kanto Plein, and the other is high tides from Tokyo Bay when a typhoon comes.

For floods from the upper rain stream, the water level of the Sumida River is controlled by the Iwabuchi watergate. When the water level from the upstream rises, the watergate is closed, and the river water flows into the Arakawa River, which is an artificial river created for a flood bypass. Since these water protection systems were created, the flooding due to heavy rain from the upper stream has decreased.

On the other hand, the downstream areas are still in danger of flooding due to a storm surge caused by a typhoon. Since there is no watergate at the mouth of the Sumida River, the river’s water level is directly affected by storm surges. In typhoons in history, water was sometimes recorded above more than 4 meters. The floodwall of the Sumida River is still 6.3 meters high, but the frequency of massive typhoons is gradually increasing due to climate change, and a significant storm surge may occur in the future.

History of major Sumida River flood water levels and damage

Flood upper rain stream

High tide

Edogawa river

Tokyo station

Sumida river

Arakawa river

Worst case high tide flood risk (if the floodwall break)

Iwabuchi water gate

Tyhoon in 2019

The Tokyo Great Flood of 1910

The Tokyo Great Flood of 1910

The Tokyo Great Flood of 1910

Tokyo’s largest storm surge inundation assumption map (flood depth)

Future flood Risk in Tokyo

Those maps show the flooding area when the sea water levels will increase in the future (flood protection is not included). Because of most of the low land, most of the eastern area of the Sumida River will be flooded. To protect the land, Tokyo needs to continue to have robust flood protections.

Sumida river

Tokyo station

Arakawa river

1.0 meter rise

1.5 meter rise

2.0 meter rise

2.5 meter rise

Transition of the Sumida River and Arakawa river

The Sumida River used to be a single river. However, between 1868 and 1910, more than ten floods occurred, especially the flood of 1910 caused enormous damage around the area. After this huge flood, The Arakawa Flood Bypass project that created an extra artificial river started to prevent the Sumida River from overflowing, and it was completed in 1930. At the same time, the Iwabuchi Watergate was created where the river divides, and it contributed to controlling the water level of the down part of the Sumida River.

1880 1924

The Arakawa River flood bypass was constructed in 1913 to 1930.

The Sumida River flowed next to the capital

Arakawa River (22 km length, 500m width)

Since the Arakawa River was created, flooding in Tokyo has decreased.

The urban area of Tokyo has expanded significantly, becoming filled with buildings

Sumida River and Arakawa river

Arakawa River

Sumida River

Iwabughi water gate

Arakwa river

Sumida river

Iwabuchi watergate

The Arakawa River (Flood Bypass)

The Sumdia River

History of the Sumida River

Over history, the role of the Sumida River and the relationship between the river and people have changed. When Tokyo was known as Edo in the 17th century, the Sumida River played an essential role as a water transport supporting Edo city’s construction (present-day Tokyo), such as being used to transport timber cut from a lumber yard. The area around the Sumida River developed as an agricultural area, and at this time, floods occurred frequently. In the 1860s, many agricultural areas around the Sumida River were replaced by factories with modernisation.

With the completion of the Arakawa River (Flood Bypass), the flood damage on the Sumida River has been reduced. However, the Catherine Typhoon in 1947 and the Isewan Typhoon in 1959 caused heavy rainfall and significant damage around the Sumida River. After that, the government constructed a flood protection wall along the Sumida River. Because it was impossible to build a large dike along the river due to a lack of sufficient space and budget, the high concrete floodwall, 6.3 meters above the average water level, was created outside the existing low revetment in a rush between 1960 and 1980. As a result, it hides the Sumida River view from inland and separates people’s lives from the water.

Around the Edo period (1600-1860)

People used to live with the river. The Sumida River has been a major transportation route for the people of Edo. At the same time, the river has been deeply appreciated and familiar to the people of Edo as a famous landmark. For this reason, the Sumida River and the many famous places along the river have been depicted in countless paintings throughout the Edo period.

Before the rapid economic growth (1880-1950)

Until 1950, the Sumida River was part of people’s daily lives. The water quality was good enough to swim, and children swam in the river in a school swimming class. The river was a valuable space, especially on the festival day, like a fireworks festival. Sidewalks were also made along the river, so the Sumida River was part of Tokyo’s common scenery of people’s hearts.

The flood wall was constructed (1950- now)

After repeated damages from flooding, the government made the 6.3m high flood wall along the river in a rush between 1960 and 1980. It hides the Sumida River view from inland and separates people’s lives from the water. Due to polluted industrial wastewater, the river smelled bad and became a place where most fish could not live. The bad smell and the invisible river triggered people’s minds away from the river.

Transition of the water edge of the Sumida River

The Sumida River edge has changed over time. Initially, it was a green river bank, but as boat transportation became more popular, small quay walls were built along the river next to houses.

During the rapid economic growth, factories and warehouses lined the river, and a 6.3 m concrete wall was built to protect the land from flooding. After 1980, the Sumida River Terrace was built to reinforce the concrete wall and open up the river space for people, and people can walk along the riverside.

River bank

quay wall

House

1980- curernt

factory

1960ground sinking

Terrace

concrete wall

Site Visit

To find out what the situation is right now around the Sumida River, I went on a site visit to Tokyo twice, in May 2022 and January 2023. The first visit is mainly to see and experience the whole Sumida River from top to bottom by bicycle. During the visits, I took photos and sketched around the river. Based on this, profiles of the whole river were created. The second visit was to see the design site in more detail after deciding on the direction of the design.

During the two visits, I also had a chance to have an interview with people in the Tokyo Metropolitan Government River Department and a flood protection expert. Also, I stayed at the hotel next to the river to experience the river like a citizen of Tokyo. This offered me time to run along the river in the morning, have lunch at the river space, and go night walks with friends. This experience deeply connected me to the river, even during these short visits.

Views of the Sumida River

The variation of the flood walls’s facade

Sketches during the site visits in Tokyo

Sumida River section research

Before visiting Tokyo, I created preliminary profiles of the entire river using Google Maps. During my stay in Tokyo, I cycled around all of the river space (23km for both sides) to check and correct the spatial profiles.

Once all the profiles were completed, I was able to capture the overall characteristics of the river from the individual sections: observing the continuity of the same profile along the river, assessing the accessibility to the river space, and extracting the visibility of the river from the space next to the floodwall.

Through analysing these elements, the profiles can be divided 5 different groups: A) Flood wall with river pedestrian space, B) space with floodwall under the elevated highway, C) space integrated with the floodwall, D) No pedestrian space next to the floodwall, E) Super Levee (new dike type protection)

Furthermore, the profiles of the Sumida River can be broadly can be divided into two main types: the flood wall type and the Super Levee type.

Bicycle borrowed from a friend in Tokyo

Locations of the photo I took on the first visit

Analysis

Using the river sections and photos created based on the field survey, as well as new information and map dates, I analysed the actual river space problems.

I also received detailed GIS information data from the Tokyo Metropolitan Government, which allowed me to visualise detailed data, such as green spaces, road, rail networks, and building types, that can be applied to an urban scale analysis in Tokyo.

The Sumida River is 23 km long, but the half upstream flows mostly through residential areas. In contrast, the downstream half flows through the centre of Tokyo, with offices, tourist spots, and amusement centres around. Compared to the upper stream, transforming the downstream near the city centre is expected to impact the huge area and wide range of people. Therefore, the project’s design will focus on the development of the downstream region.

The current situation of the Sumida River space

While these 6.3 m flood walls significantly contributed to the protection of the citizens of Tokyo, they separated the river from the city. As a result, people’s interest in the Sumida River gradually diminished. The Tokyo government created two solutions in the 1980s to improve this situation and reinforce flood protection.

The first solution was to make a river terrace next to the existing flood wall. This creates pedestrian space along the river and reinforces the flood wall construction, especially for earthquakes. The second solution is to make the Super levee a huge dike and combine it with building plots, combined with the terrace.

The section research shows that the river edge can be divided mainly into those two solutions.

70%

Super levee

Super levee

30%

Sumida river terrace

Flood wall

Super levee

Current location of the flood wall and super levee

Flood wall + river terrace : spatial problems

Despite the Tokyo government’s efforts to create the river terrace, I couldn’t see the space was utilised. Site visits and research have revealed the following issues in the river space.

1). Monotonous design of the terrace: Most of the terraces are made of hard pavement and flat surfaces with 8 m width. Some parts have green benches or water features, but the same design continues along the river and doesn’t motivate people to stay.

2). Dead space behind the flood wall : A pedestrian path is made behind the wall. In many parts of the path, people can’t see the river. Moreover, some parts are closed and cannot be accessed.

3). No connection to the city fabric : The access points to the river are also limited. Many streets hitting the river are dead ends, and no stairs or slopes can access the river.

Dead space

Dead space behind the wall

No connection to the city fabric

Dead end from the street

Monotonous design

Monotonous paved surface

Design not well-thought

Hard edge

Flood wall

Path overlooking the river

River invisible path

The Super levees

Tokyo’s government also developed the concept of a super levee in late 1980. The super levee is constructed to strengthen the safety against a potential strong earthquake and flood and improve the riverside environment for people instead of the flood wall. Construction is integrated with redevelopment and other community development projects along the rivers. Even 40 years after its introduction, the super levee concept has completed only about 30% of the riverside because the super levee project has high costs, long construction times, and displacement issues. However, the government still aims to make the super levee the whole riverside in the future.

Green slope super levee

Super levee

Steps design super levee

Issues of the Super Levee

There are some issues with the further realisation of the super levee.

The first issue is ownership of the building property. Most of the building plots in Japan are owned by private owners. The super levee construction requires extra space from their private property, so the super levee’s feasibility depends on the property owner’s agreement.

The second issue is the size and phase. The Super levee is a project in adjacent building units, many of which are only applied to larger buildings. In fact, super levees cannot be seen on buildings as small as 15 meters in width. In addition, the feasibility of super levees depends entirely on the building and its owner, as they can only be planned when the building is redeveloped.

Because of those reasons, the completion rate remains at 30%. I think this super levee solution will not be suitable for the high-density urban context in Tokyo in the future. A new way of flood protection adapted to Tokyo’s complex context will be needed.

Large Buidling with the super levee

110m

No super levee with middle or small buidldings

15m

What is the river for the city?

The city of Tokyo is constantly busy. People are always on the move. Shops or information are overflowing. People are overwhelmed with speed and density. Many people work long hours and spend their days going back and forth between work and home. How can public spaces contribute to busy people’s lives in this situation?

During the site visits, I saw people spend their time with the river occasionally. I also found a small inner peace that made me forget the fatigue of being in the city.

The river provides fresh air, panoramic views, a vast sky, and quietness with the sound of birds. Through my field research, the Sumida River has the potential to become an essential public space for the people in Tokyo to take refuge from their hectic daily lives.

wider view of water and sky

wind and cool air

slow temp with the water

Goal of the project

The main goal of this proposal is to reconnect people to the river by enhancing the accessibility and quality of the river space.To achieve that goal, the design solution is to revitalise the river space and connect the river space with surrounding public space or inner city fabrics. By forming a new continuous public spaces network based on the river space, the Sumida River, which has become the city’s backside, could be a main public space axis. So, in the end, this project aims to reverse the Sumida River into a new focal point of the city.

This graduation project consists of three different approaches. The first approach is connecting the city fabric to the river through walkable streets, allowing people to reach the river space from the inner city more recognisable. The second approach is integrating important public spaces into the river space, such as parks or major spots around the river. The third approach is creating new river spaces as continuous public spaces along the river with identities considering the surrounding urban context and the river landscape.

Design methods

1. Connecting the city fabric to the river through pedestrian streets

2. Integrating important public

spaces into the river space

3. Creating new river spaces as a continuous public space along the river.

Design

Goal 1 - Connecting the city fabric to the river space

Approach : Transform traffic road to pedestrian friendly street

When visiting the site, I found that there is no direct connection between the rivers and the inland city. People’s movement in Tokyo mainly relies on trains or buses, which prevents them from having a practical sense of distance through walking or cycling. During my stay in Tokyo, I mostly used a bicycle for transportation. I found that I could reach most of the major destinations by bike and also that the Sumida River and the main areas were within walking distance.

Even if the river space is developed, if there is no clear accessibility from the city, the space will not be activated. Therefore, as Goal 1, I propose people-oriented streets that connect the rivers and major areas of Tokyo. These walkable streets, with green and tree shade, connect schools, stations, and parks, and they will be a main route not only for local residents but also for visitors exploring Tokyo.

Road network and street conditions

Tokyo has a grit structure road network. Many of these streets still prioritize cars and there are many small streets with no sidewalks. Children in the city use this narrow pedestrian path to go to school.

In addition, most of the small streets are not planted with trees due to the electrical wires and utility poles, and there is only asphalt. Therefore, the streets lack a unique identity, and many people choose a route as the shortest route.

Popular Districts around the river

There are many famous spots around the Sumida River. From famous historical sightseeing areas, museums, shopping areas, and Japanese gardens. Even though they are located within walking distance of the river, there is no clear connection between them. And many people, from locals to tourists, visit those areas by train or bus. Connecting those areas to the Sumida River by walkable streets can be one strategy to create a chance for people to meet the river.

Ueno

Akihabara

Asakusa

Tokyo station

imperial palace

Nihonbashi

Ginza

Tsukiji Fish market

Hama-rikyu Japanese garden

Restaurant street

Sky tree

Ryogoku

Kiyosumi japanese garden

Contemporary Art museum

Ueno shopping street

Asakusa Sensoji Temple

Ginza shopping are

Tsukiji Fish market

Sky tree landmark tower

Ryogoku Sumo Arena

Kiyosumi Japanse garden Hamarikyu Japanese garden

Schools and Stations

There are many schools around the Sumida River, from kindergarten to university. To select walkable streets, I consider the routes that connect railways, schools, and parks to ensure that the streets will be functional for both locals and visitors.

Legenda

Famous District

Rail lines

Stations

Park

School Plot

Kinder garden

Elementary school

Middle school

High school

Universities/Technical College

Selected walkable streets

I selected routes from major spots toward the river and made two street design principles: residential streets (medium and small) and office area streets. Each street has a 500m to 700m interval each other and stretches from the river to the inner city. So, from many points in the city, people can reach the pedestrian street. During the 2nd field survey, I visited all the streets and checked for alternative routes if the traffic was limited for each street.

case study 2

case study 1

Residential

Case study 1: Small Residential street

Case Study 1 focuses on the Asakusa area, a well-known tourist destination. This area is rich in historical temples and shrines, providing an opportunity for experiencing Japanese culture for tourists.

Also in this area, small residential houses are clustered together with a few elementary and middle schools around. Therefore, I selected the route extending from Ueno Station, which is one of the main stations, towards the Sumida River in the Asakusa area, connecting with elementary and middle schools, parks, and shopping streets.

Temples Shopping arcade

Ueno station

Sensoji temple

Asakusa area

Asakusa station

Elementary school

Sumida river

Section transformation : Small Residential street

Currently, the street lacks pedestrian space, providing only a narrow walking space of 1.75 meters, and there are no street trees due to the utility poles. Taking advantage of one of the Tokyo government’s initiatives: making an earthquakeresistant city with zero utility poles and underground electricity pipes, this street will be transformed by putting power lines underground and will be redesigned with trees and a low planting area.

Due to limited property space, many residents in this area do not have their own gardens. Instead, they place potted plants on the street. By designing the street’s planters as semi-private green spaces, residents can utilize them as their own gardens. Residents’ awareness of the plant management will also be an eye for safety for children on their way to school on the street.

Case study 2 : Office and Shopping area

Case Study 2 focuses on connecting Ginza, a famous shopping area in Tokyo, to the Sumida River. The area also consists mainly of a shopping district and an office area, but the Tsukiji Fish Food Market, Hamarikyu Japanese Gardens, and Tsukiji Honganji Buddhist Temple are located in the neighbourhood, attracting many domestic and foreign tourists.

In order to connect these major spots to the river, the street lined with cafes and restaurants was selected for this area. The design aims to create a square like street which has a space where restaurants can set up their terrace seating on the street.

Tsukiji Honganji Buddhist temple

Hamarikyu Japanese garden

Section transformation : Office area street

The current street is divided into a roadway and a promenade, with middle trees on both sides of the street. However, the street functions only as a traffic line, with no space or features for people to stay.

The design minimises the entry of cars, for example, only essential functions such as transporting, and transforms the street into a pedestrian-friendly environment where pedestrians can walk in the middle of the street surrounded by greens. The main walking space in the centre of the street has a large rhythm of space that allows the surrounding restaurants to create terrace seating. This creates a lively atmosphere on the street where tourists or local workers gather to take breaks. and also guides people to the Sumida River side.

Goal 2 - Integrating important public spaces to the river space

Approach : Expand the river space into the famous place

Goal 2 focuses on the significant area along the river space, aiming to create interconnected river spaces between the riverside and the inland areas. The main method is to expand the river space to the space owned by the metropolitan government, such as roads or parks, and to connect the seamless flood protection space that will replace the floodwall to the main tourist spots around the levee.

Case study : Two design areas

Sensoji Temple

Tokyo sky tree tower

Ryogoku Sumo Arena

Calture museums

Highway

Asakusa area

Sumida park

Sumida park

Ryogoku area

Asakusa area

Ryogoku area

Pedestrian street

Sensoji temple area

Pedestrian street

Pedestrian bridge

Tokyo Sky tree

Sumida park Sports park

Sensoji temple

Pedestrian Bridge

Cherry blossom

Main Shopping street

Case study 1 : Asakusa area

Approach: Connecting two famous area by the riverside park

The Asakusa area and Tokyo Sky Tree are major tourist attractions in Tokyo. Between them, Sumida Park is located on both banks of the river. Currently, Sumida Park is obstructed by the flood wall and a two-lane road, and there is a lack of eastwest connection from the river.

Therefore, in this case study, in addition to the design of pedestrian streets outlined in Goal 1, the aim is to integrate the river and Sumida Park into a cohesive design, creating strong connections with the surrounding areas. The profile will be changed from the flood wall type to a slope flood protection that creates smooth access to/from the river. Sumida Park is also known for its cherry blossoms, so the transformation of the topography of this park creates a new scenic spot where visitors can view the cherry blossom valley from their boats.

View 1

View 2

Section transformation :Expand river space

Current situation

River space

Proposal

River space

boulevard

Sumida floodprotection Park

Japanese Sword Museum & Japanese garden

Tokyo Memorial Hall

Edo-Tokyo Historical Museum

Ryogoku station

Ryogoku sumo arena

Ryogoku sumo arena

Edo-Tokyo Historical Museum

Tokyo Memorial Hall

Japanese Sword Museum

Case study 2: Ryogoku area

Approach: expanding the river space as bridging to each facility

The Ryogoku area is Tokyo’s cultural district, with museums and cultural facilities. Surrounding the Ryogoku area, the Museum of History Tokyo, Yasuda Japanese Garden, and the WW2 Memorial Hall are located. In particular, the Ryogoku sumo arena is the site of official sumo matches, a traditional Japanese sport, and is visited by sumo fans from all over the country. However, this area is also poorly connected to the river. Not only the concrete flood walls but also the elevated Metropolitan Highway, the 2-lane road, and the parking lot create barriers between the riverside and this area. It is hard to access the Sumida River or even see the river from this area.

In this design, the 2-lane road is partially underground, and the above-ground space is designed as a walking space integrated with flood protection that allows easy access from the river to the major facilities. 6.8m high flood protection point is extended inland, and its gentle staircase or slope connects towards the facilities’ entrance.

view 1

View 2

Current situation: Major places disconnected by infra and buildings from the river

Approach : Connecting major places by flood protection path

Goal 3 - Designing new river spaces

Approach: Developing the flood wall profile, revitalising the river as the city’s public space

In Goal 3, the aim is to redesign current monotonous river spaces into new characterised river spaces. Currently, these spaces lack distinctive features or variation across different locations. This results in a lack of design coherence and a disconnect from the surrounding buildings or contexts.

Therefore, Goal 3 involves reinforcing ageing flood walls and incorporating new interventions as space for humans and nature. Also, the design will create a continuous walking space on both the front and back sides of the floodwall so that the entire Sumida River will be a continuous axis of public space where people can walk and stay without interruption. The design is based on integrating the characteristics of the surrounding context and the Sumida River landscape character, forming three major identities.

The danger of flood wall breach

The floodwall consists of several concrete partitions connected to form a long, continuous wall. Most of these walls were built in the 1960s and are ageing.

When I had an interview with the flood protection expert in Tokyo, he explained to me that this wall would be in danger of breaking at the joints part when flooding and earthquakes occur at the same time. When I visited the flood wall, I found that the rubber at the joints was deteriorating and did not appear to be well maintained.

joint part

joint part

The reinforcement at the connecting joints is not well-maintained

Reinforcement with Spatial Quality

As a design method, I propose a reinforcement design to cover this fragile joint part from the front and back. The new space will be designed to allow people, animals, and plants to intervene and improve not only the strength of the floodwall but also the spatial quality of the river space.

The base design approach is creating pedestrian pathways behind the wall, allowing people to walk while overlooking the river. On the river side of the walls, new features such as lookout places, planting spaces, wetlands, and steps are introduced to create a new character for the riverfront space.

Lookout place

Playground

Theater

Wetland

Forest

Communal garden

Walking path

Walking bridge

Mix of apartment and small size office

High-rise office/apartments with business district

Tourist attractions with Japanese culture

Three different characters as the river space

To change the monotonous river spaces lacking variation across different locations, the design begins by establishing broad characters. By combining the characteristics of the area surrounding the river and the Sumida River’s landscape, three main identities are formed:

The upper part has many traditional and historic facilities, and the surrounding area will be given the ‘CULTURE’ character.

The middle part of the river meanders, and the sedimentation caused by the different flows of the river is a ‘NATURE’. The lower part of the river is an area lined with high-rise buildings and is characterized as ‘URBAN’.

Identites

Riverlandscape

Sedimentation

citycharacteristic Infrastructure

Three River identity

CULTURE

Straight river

Many bridges

Under highway

Tourist District: Historical Museum, Temple Cafe, Restaurant

NATURE

Curved river River dynamic Sedimentation

Green along the river Residential area

URBAN

Wider water

Transition to the sea

Ship traffic

Business District

Highrise building Tourist District

Existing situation

view 1

view 2

view 3

Sensoji Temple Sumida park

Tokyo sky tree tower

Ryogoku Sumo Arena Calture museums

Terrace walk Under

CULTURE area

The upstream area is surrounded by numerous cultural facilities. Historically, the Asakusa area has been lined with many dining and entertainment facilities, some existing along the river’s western banks. Tourists seek picturesque river views along these riverside restaurants or cafes. In this area, the design aims to integrate the terraces of these restaurants with the river space by walking a bridge walk.

Furthermore, The highway running over the river space on the east side will be utilized to design an under-highway park that can be used even in the rain or hot summer days.

bridge walk

Under higway park

Existing river terrace and balcony

The field survey discovered that restaurants with riverside terraces are clustered in the Asakusa area, the western riverbanks.

Most of them are either small balconies or terraces that extend above the flood wall. The Tokyo Metropolitan Government is promoting this type of terrace, allowing restaurants and cafes to install terraces as close to the flood wall, provided they obtain approval from the Tokyo Metropolitan Government.

This initiative began around 2018, and the Asakusa area has been actively moving toward the installation of terraces.

Current river view terrace

Terrace

Balcony

Plan: Terrace walk

The pedestrian bridge, which can be connected to the existing terrace, integrates flood wall reinforcement and a walking path. The bridge leads to the terraces of each café, providing a second entrance for visitors. It also functions as a public promenade, offering panoramic views of the river while walking. Underneath the bridge, benches and planters are incorporated to create a space where people can linger in the shade of trees.

Section: Terrace walk

Elevated highway and the river space

In the area east of the Sumida River, there are no buildings standing along the river because of the elevated highway, and a two-lane road runs north-south next to the floodwall. Here, the location of the floodwall is moved toward the road to expand the river space and make the space under the elevated highway function as an activity space for people.

Section: Under Highway park

Under the elevated highway, the expanded river space will be designed as Under highway park, serving as a venue for sports, theatre, and playground activities unaffected by rain or intense sunlight. Here, people can enjoy their own activities while overlooking the river.

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Existing park

Sedimentation wetland

River

Sedimentation

Japanese garden Commercial

Residential

Residential

River

Nature area

In the central area with a large meandering river, the design embraces the dynamic features of the river. It was found that there is sedimentation inside the curved river from the sedimentation map from the Tokyo government office. The aim is to create a small network of nature within the city by creating an ecotone tidal pocket on the inner side of the river and river forests as stepping stones for living creatures on the opposite outer curve.

ecological shore

Sedimentation

River forest

Sediment in the Sumida River

Due to the flow from the upstream, sediment accumulates at the bottom of the Sumida River. The Tokyo Metropolitan Government makes riverbed a cross-sectional survey every four years and uses those drawings as a guide for dredging operations to remove sediment.

Connecting the drawings provided by the Tokyo Metropolitan Government revealed that sediment accumulates more on the inside curves of the river, similar to natural river systems.

Once a few years, dredging work is performed.

Sedimentation sections received from the Tokyo Government office

Tidal land on the inner curve

During the field survey, it was confirmed that there is sedimentation tidal land in the inner large curves part, upper stream. Gobies and shellfish inhabit here, and birds that prey on them are also seen.

Encountering such natural features within Tokyo was a unique experience for me, and seeing the changing appearance of the tidal land made me realize that the Sumida River is still a living river, despite being reinforced with concrete quay,

Taking inspiration from this sediment-formed tidal land, the concept of this area is to leave the sediments on the inner river without dredging and to create a soft edge in the urban river where living creatures can habit.

Current : Only hard edge

River dynamics into the river space in the urban river

Sedimentation as ecological shore

Sedimentation wetland ecotone

Here, the main characters are water creatures. At the inner curve of the river, a space is created to serve as an ecotone where water creatures can habit. The pavement of the river space and part of the quay wall will be broken up to create a tidal pool.

The sediments create a slope on the riverbed that extends to the tidal pool, with the appearance of the tidal land changing with the tide. The different depths of the tidal pool offer a habitat for diverse aquatic plants and creatures.

Little egret

Cormorant

Gudgeon

Mitten Crab lake prawn

Sea bass

Mullet Carp Eel

shallow water

Deeper water

Plan: River forest

Section: River forest

On the opposite bank, the outer curve of the river has fast-flowing currents, so the existing hard quay wall remains here. To introduce the flow of creatures from the Eco tone as stepping stones on the opposite bank, the river space aims to design a small natural area with forest elements.

The new reinforced wall keeps the green sloped, creating an oasis of greenery within the river with natural landscapes, deciduous trees, and shrubs, softening the hard-paved urban environment.

Mixed deciduous trees

- Maple - Hornbeam

- Zelkova

Possibility of the future building typology

Behind the flood wall, a new walkway integrated with reinforcement is designed. In the design, this new pedestrian path is made higher than the existing path, offering a view of the river.

Currently, most of the space between the flood wall and buildings is almost dead space. Introducing pedestrian flow in this space creates an opportunity for new cafes and shops with entrances facing the river. This design has the potential to inspire new typologies in future architectural designs with the connection of the pedestrian path along the river.

Existing situation

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URBAN area

Urban waterfront park

Ginza shopping area

Tsukiji honganji temple

Tsukiji fish food market

Tsukishima food street

New development area (Baseball stadium)

Japanse garden

Residential apartment

Residential house

Commercial building Warehouse

Park Office

Urban area

The mouth of the Sumida River was created by reclaiming the sea, so the river is wide and looks more like a harbor than a river.Many of the surrounding buildings are also skyscrapers, so here, the sense of the urban water landscape can be characterized by this area.

The design aims to create viewing points where visitors can enjoy the skyline of the cityscape with elevated buildings and iconic bridges, as well as the river view.In addition, due to being close to the ocean, the water has a large tidal range. Using this character, the water steps, which change according to the tidal range, are introduced.

High-rise building

High-rise building

Plan: Urban waterfront park

Section: Urban waterfront park

The reinforcement of the floodwall integrates with terraces, providing an elevated structure from which the urban landscape can be viewed. The river space is basically made of hard pavements for the walking area, and on the wall side, a green slope with grass or stairs offering a place to sit or lie down towards the water view. On the riverside, the water steps will be created that appear and disappear by the tidal. Visitors will perceive the natural cycle of the tide by seeing the different sizes of the steps.

current

Masterplan

When these three design approaches are realized over time and connected together, they will form a new urban public spaces network in Tokyo. Through this design, the Sumida River, hidden behind the flood walls and relegated to the city’s backside, will become the central axis of a new network of public spaces.

I hope this design encourages a reconnection between people and the river and transforms the river’s value into an essential place again for the people living in the city.

Model : River forest

Scale 1:100 , Size: 60 x 80 cm

Special thanks

This graduation project would not have been possible without the contributions of the following people. I’m deeply grateful for all your support and collaboration.

Marieke Timmermans (mentor)

Yttje Feddes (committee member)

Hiroki Matsuura (committee member)

Yuka Yoshida (expert)

Hanneke Kijne (Former head Landscape Architecture of the Academy)

Nobuyuki Tsuchiya (Flood protection expert/ Japan River Front research Cenrter)

Daichi Kosuge (Tokyo Metropolitan Government Construction Bureau River Department)

Hideaki Shimura (Professor Shibaura Institute of Technology)

Colleagues Gemeente Amsterdam

Maki Ryu

Reinier Gramsma

UNIT4 Collective

Yukio Mabuchi

Stichting NHBos

Topography

Residencial buildings

Legenda

House

Apartment

Office, Commercial, Factory buildings

Legenda

Commercial facility

Office Commercial + Residencial

Factory

House combined factory

Warehouse

Stairs

Slope

Super Levee

Sumida Park

Hamacho Park

kiyosumi japanese garden

Yasuda japanese garden

Ueno park

imperial palace

Hama Rikyu japanese garden

Public space around the river