Sponge Cities - China’s Green-Blue Approach to Urban Water Management
Conventional city design has allowed society to thrive and grow in a range of challenging and often uninhabitable environments. However, as global populations increase and shift from rural to urban areas, the scale of urbanised regions is causing increased stress on the natural environment and its supporting systems; one importantly being the water cycle.
The natural water cycle is disrupted in urban areas because buildings, concrete and other sealed surfaces prevent water from soaking into the ground. As a result, natural water flows are altered, and excess stormwater is created, which is traditionally directed into local waterways via drainage networks. This disruption to the natural water cycle causes many problems, including:
- Polluting waterways, bays and oceans
- Waterway erosion and degradation
- Urban flooding
- Decreased soil moisture
- Reduced groundwater levels
These problems have become significant issues for China and its rapidly urbanising cities. Between 2011 and 2013 alone, China used more cement than the United States did over the entire 20th century (USGS, International Cement Review).
Areas which were once rural farmlands are becoming impermeable cityscapes that generate vast amounts of stormwater. Due to the scale of development, piped drainage systems can suddenly become overwhelmed and flooding is now a regular occurrence for many Chinese communities.
To address this, Beijing is piloting a new permeable city concept called ‘Sponge Cities’. A Sponge City is designed to locally absorb, treat, and slowly release captured rainwater to mitigate the impacts of flooding and stormwater pollution. This is achieved via implementing a network of permeable surfaces and ‘green-blue’ infrastructure options to help restore the natural water cycle within heavy urbanised areas. These infrastructure options typically include vegetated rooftops, raingardens, wetlands, and stormwater re-use systems.
Green-blue infrastructure options perform many of the same functions as their traditional “grey” infrastructure alternatives, and are often more cost-effective as they offer a variety of measurable environmental, social, and economic benefits. Conventional grey infrastructure —concrete channels, piped drainage systems, and treatment plants— tend to be single purpose, whereas green-blue infrastructure are multifunctional and offer a resilient, decentralised stormwater network.
Yanweizhou Park in Jinhua (eastern China), completed in 2014, serves as an example how city spaces can ‘absorb’ water and serve as engines for tourism, city greening and urban wellbeing.
The importance of the natural water cycle within urban environments is being recognized in many countries around the world. In Australia the practice is known as water sensitive urban design (WSUD), low impact development (LID) in the US, and sustainable drainage systems (SuDS) in the UK.
Through a partnership with the CRC for Water Sensitive Cities, the E2Designlab team has been assisting the City of Kunshan in Jiangsu Province to transform it into a world leading sponge city, demonstrating enhanced ecology, liveability, and resilience.
Selected projects include:
Kunshan Tinglin Park Sponge Design
Tinglin Park project addresses three of the park’s main environmental issues - waterway deterioration, mountain erosion, and static lake water quality deterioration. Integrating green infrastructure responses with traditional Chinese Garden landscape design, E2Designlab offered a systematic solution that was scalable from a local to regional level.
Kunshan Integrated Water Management (IWM) Strategy
E2Designlab developed a systematic water management framework for Kunshan through a IWM approach to reduce the water consumption, wastewater generation and stormwater pollution for both domestic and industrial activities, minimising the basin’s water footprint.
Kunshan Forest Park Water Management and Eco-restoration
This project aims to improve the water quality of five large park lakes by transforming traditional green space into multi-functional green infrastructure which provides water treatment, water recirculation, and extra flooding storage, within a versatile landscape. In addition, an ecological restoration zone is planned to protect and remediate the local aquatic and terrestrial habitat, restoring the ecological values and encouraging flora and fauna back to the area.
Interested in transitioning to a resilient, water sensitive city?
Contact E2Designlab at: [email protected]
- CRC Water Sensitive Cities: https://watersensitivecities.org.au/wp-content/uploads/2016/12/CRCWSC_TradeMissiontoKunshan_R2.pdf
- BBC News: http://www.bbc.com/news/world-asia-china-33802777
- Business Insider: https://www.businessinsider.com.au/china-is-building-sponge-cities-that-absorb-water-2017-11?utm_content=buffer5d4cb&utm_medium=social&utm_source=facebook.com&utm_campaign=buffer-bi&r=US&IR=T