Master Thesis: Water Urbanism

WATER URBANISM

The Jiangnan Wetland & Water Village Corridor Suzhou, Yangtze River Delta metropolis, China

VOLUME 1_EXPLORATIONS VOLUME 2_DESIGN INVESTIGATIONS Spring Studio 2017, Suzhou, China 2017 K.U.Leuven, Master of Human Settlements, Master of Urbanism and Strategic Planning.

Suzhou

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RE-PROFILING THE GRID CITY Framing development through stormwater mitigation

Suzhou is one of China’s oldest cities renowned for its distinct gardens, silk weaving history, and the network of canals, which the latter have brought upon the city being labelled to as ‘the Venice of China’. Due to its highly water influenced landscape and located along major waterways, with many canals connecting into a regional network of waterways that linked to the Grand Canal, the city was once a major commercial centre of China until the twelfth century. Due to the city and the environment’s close relationship with water, the area has a strong ecological significance to the region. Thus, development and lifestyle of the people within the Suzhou region was highly tied to the canals and waterbodies present. Fast forward to 1992, the Yangtze River Delta region experienced industrialisation rather rapidly compared to the rest of China, in response to the promotion of economic development in the country. The drastic growth in industrialisation brought upon a high inflow of migrants into the region, contributing further to the rapid urbanisation and hence, the change in landscape. The effects of such swift development of urban areas can also be seen in the Wujiang District, formerly known as Wujiang City, one of the five urban districts in Suzhou. This urbanisation process have forgo the once significant role of the large water system present, leading to the mistreatment of water as a valuable entity. The average yearly precipitation in the Wujiang region is approximately 1100mm, with the highest average monthly rainfall recorded in the month of June in 2016 at 277.43mm and 296.53mm in 2015.

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evolution of wujiang- from soft to hard

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Wujiang has evolved to become a rapidly growing city of high rise towers and has a strong industrial influence. It is one of the major cities in the region with a population of 1.275 million. It is a city built next to Taihu Lake and along the Grand Canal. It used to be a water-based city, sensitive to water, but has transformed into a rigid grid-based urban area. The city is expanding into unbuilt territory towards the south and west. The speculative nature of this urbanization resulted in more built areas in the city thus, adding pressure to the already problematic water network. The development, which is mostly residential, disregards water. The logic of development, followed the development of the industrial zone. Infrastructure is laid in the sponge landscape and development occurs in a grid of 400x400m making these ‘islands’ more impervious and a threat to the ecological value of the area.

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existing urban condition

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legend Industrial

Highrise

Slabs

VL in Urban

VL in Industrial area

Villages

Canal

Old town

Mixed use building

Detached houses

Lake/ pond

Agriculture

public amenities

corridor pollution impact

Water pollution in the corridor is caused by the urbanization, heavy industrial presence in the city, and aquacultural and agricultural activity. While aquacultural and agricultural activity play a big role in contributing to the water pollution problem, their presence within the urban limits are limited. Moreover, hard engineered and controlled water systems, and flood gates control the issue in certain parts, but add stress on other areas, further increasing pollution level. Due to this, the corridor’s sponge territory and water network has different qualities and levels of pollution. Many parts of the corridor are polluted with levels above three. Taihu Lake, a significant fresh water body is at a pollution level of three; the Grand Canal has the highest water pollution level within the

corridor. This is incredibly significant as the Grand Canal is connected to the Taipu River which is the main source of drinking water supply for the Shanghai region. The flow of water in the Grand Canal coming from the north is both influenced by a ‘plate-like’ topography and also by engineered gates and canals that further introduces flow from the west to East. The water pollution level of the Grand Canal which is out of scale is one of the primary sources of pollution to the corridor while also a receiver of pollution from the city. This makes Wujiang city and the area linking to the Grand Canal an ideal location for an intervention that mitigates water pollution levels throughout the region.

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reprofiling the grid city: local and regional stormwater infrastructure as framework for future development

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Strategies

Strategies

Densification in the existing city While the three strategies work simultaneously to provide one coherent system, the design of the strategy of densification through new tissue typology is largely influenced by the objective of localizing stormwater management through blue-green infrastructure. The available land for further development and densification is then limited by the creation of a Mega Park system, requiring a shift in building rights, (due to the consumption of available semi-developed land) primarily towards the south of the city.

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Retention pon

CLEAN

CLEAN

Lakes Wetlands

STORE

Lakes Wetlands

FROM rooftop

DELAY

INFILTRATION

Permeable surfaces Bioswales

DELAY

INFILTRATION

Permeable surfaces Bioswales

STORE

Green islands: retain, restore, release

Cleansing park

Canal

DISCHARGE

Green spaces Local island stormwater management green infrastructure

DISCHARGE

Green spaces

Collaboration between different types of blue and green infrastructure

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Stormwater detention, retention and discharge mechanism

FROM rooftop TO ground Street DELAY

INFILTRATION

To deal with water pollution, the first strategy is to create a localized water treatment system within the ‘islands’ of the city. Water runoff from hard surfaces and streets will be collected and channelled through permeable pavements, surfaces bioswales, and rain gardens.Permeable A process to ‘retain, restore, and release’ will be Bioswales conducted through a series of blue-green infrastructural interventions, cleaning the runoff water, before they reach water sources, and restoring aquifers in the process.

Retention pond

CLEAN

STORE

Lakes Wetlands

Cleansing park

Retention lake

DISCHARGE

Green spaces

Canal

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Stormwater infrastructure through street re-profiling

Grand canal car way - Redefinition

The redefinition of the small car street along the Grand Canal softens the bank, manages runoff and provides recreational space

4 lanes- Rethinking a typical urban vein

Bioswales would be cut out of the existing street, managing runoff from the street and providing landscape for pedestrians.

Vast pavement- Incorporating variety

The mono-functional pavement is redesigned into linear landscape, using the fill from swales excavation, to host a variety of functions.

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2 lanes- Rethinking the local car access

The small street for local access is rethought as a neighbo hood linear park by introducing bioswales, and providing recreational space for the already vibrant street activities.

Small canals- Emphasizing the identity of Wujiang

Along the small canals, hard edge banks are transformed into soft and permeable landscape that deters and filters particles from street runoff, at the same time emphasizing the canals of Wujiang.

Under-used car roads are also transformed into bicycle lanes and pavements.

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the mega park

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SCENARIO OF MEGA PARK

Absorbing polluted water and preserving identity landscape: Mega Park as water cleansing corridor To make the stormwater infrastructure to act as a system, a series of park types connected through green-blue infrastructure are proposed, to make up a Mega Park.

Open-space around Taihu Lake will become an ecological park to restore the ecology and water quality of the lake surrounding the city. Wetland parks are ‘island’ focused, receiving runoff and grey water from the urban area before it gets to the Grand Canal. Cleansing parks lie in the south, together acting as a ‘cleansing machine’ to clean the polluted water directly from the Grand Canal. And industrial cleansing parks deal with runoff from industrial areas.

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cleansing park

urban area

Absorbing the flowing water- A mega task for a mega structure The Mega Park system encompasses the second layer of the water pollution mitigation system. Addressing the pollution from the canal network directly, large volumes of water are channelled through the various types of parks on multiple scales, to provide natural cleaning services on a much larger scale before re-joining the network. While the park serves as a large water cleansing mechanism, it also plays through the network of green spaces creating a corridor surrounding the city. The corridor hinders further unnecessary sprawling of the city, reducing the growth of the concrete jungle and protecting the agricultural land beyond its ‘borders’.

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Indust

trial area

cleansing park

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STRATEGY II-LOCAL CLEANSING THROUGH WATER INFRASTRUCTURE Existing

traidtional water town

intervention in the existing city situation

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intervention

SLABS

SLABS

RELOCATON

RELOCATON

OLD CENTRE

OLD CENTRE

INDUSTRY

INDUSTRY

Along the small canals, hard edge bank would be transformed into soft and permeable landscape that deters and filter particles from street runoffs. It also serves as an identity landscape that emphasize the canals of Wujiang.

The car roads that are underused would be transformed into bicycle lanes and pavements. The safe environment then could promote openings of the existing gates, utilising the new beautiful landscape.

2 lanes- Rethinking the local car access

The small street for local access could be rethought as neighborhood linear park by introducing swales, providing micro climates and recreational space for the already vibrant street activities.

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The Grand Canal new development - Land right exchange

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New development: scenarios of industrial convert and new town design In order to free up open space for productive landscape, alternative sites need to be selected in exchange for the undeveloped lands that are planned for development. And a third strategy is to identify a strategic area for dense development that is attractive to developers, so that they consist to the exchange. The locations of these developments are selected along the improved grand canal and close to existing infrastructure and the city center. The new developments bring in new models of urban development that are water sensitive and that improve the urban realm.

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New densification areas (through land right shuffling): Living with the new stormwater infrastructure

Commercial building Permeable Sloped Bank

Cyclist-friendly pedestrian path

ZOOM IN 1 40

Canal

Slow Speed Car Access

Grand Canal

Retention pond Wetland park

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New densification areas (through land right shuffling): Living with the new stormwater infrastructure

Car access pavement

Urban park

ZOOM IN 2

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Canal

Sport area

Semi-public spaces

Permeable Pedestrian path

Retention pond

Retention lake(wetland)

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