Climate Resilient Sponge Cities – Concepts and Tools to Integrate Green-Blue and Grey Systems

Rau, Stefan (2024) Climate Resilient Sponge Cities – Concepts and Tools to Integrate Green-Blue and Grey Systems. KEEP ON PLANNING FOR THE REAL WORLD. Climate Change calls for Nature-based Solutions and Smart Technologies. Proceedings of REAL CORP 2024, 29th International Conference on Urban Development, Regional Planning and Information Society. pp. 123-135. ISSN 2521-3938

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Abstract

Climate hazards from increased frequency and severity of extreme weather events require urgent urban adaptation action to increase resilience against flooding, landslides and extreme urban heat, as some of the highest risks. Nature-based solutions (NbS) in the form of functional urban green can effectively reduce disaster risks (IUCN, 2020; L. Arjan et. al., 2021). Ideally such green-blue infrastructure would form networks and be systemically integrated with gray infrastructure like drainage pipes to optimize resilience against flood risk. This paper looks at the Sponge City program in the People’s Republic of China (PRC), which incorporates a range of water-related nature-based solutions to manage natural water cycles in cities and reduce urban runoff and flood risk, locally capturing, retaining infiltrating, and harnessing rain- and stormwater reused as water resources, increase local natural infiltration and threrby also cleaning stormwater. Technical guidelines were issued and 30 pilot cities were supported in 2015 and 2016, followed by 60 demonstration cities in 2021 and 2022 (Ministry of Housing and Urban–Rural Development, 2014). The key indicator set by the government has been to capture 70% of annual rainwater in the pilot areas. A recent study suggests that this has been achieved in the three cases used (J. Wu, 2022). While this concept is not new, it is now being applied by an increasing number of cities around the world using this name (for eaxample: Hamburger Stadtentwaessering, 2015). Sponge cities in the PRC and elsewhere should be mainstreamed and better integrate with gray infrastructure to be most effective and efficient resilience systems to reduce flooding and extreme heat while also delivering a whole range of other ecosystem services as co-benefits, including contributions to climate change mitigation (for example: G. Browder et al. 2019). Not least public health, recreational benefits and land value increase can be captured. Planning and implementing green-blue systems as retrofitting of existing urban areas is challenging and requires strong stakeholder and community participation. Mainstreaming NbS and sponge cities as part of risk-informed and integrated urban and regional planning of new urban areas in urbanizing Asia and Pacific and Africa is essential considering the reality of rapid temperature increase and increased climate variability. The Asian Development Bank (ADB) is committed to be the climate bank for the Asia and Pacific region. ADB supports, among others, green city development, climate risk assessment, resilience investments inclusive of NbS and sponge cities, and contributed with advancing methods and pilot projects (ADB, 2016a, 2016b and 2019). This paper offers an overview of sponge city in the PRC, technical and policy dimenions and initial observations on strengths and weaknesss of implementing the 30 plus 60 pilot and demonstration cities. A key conclusion is: it is essential for cities to establish effective green-blue NbS resilience systems. Effective gray engineeering infrastructure systems in cities are very much also needed. Systemically integrating both, green-blue and gray systems is essential to delivers best results. With the required urgent comprehensive transformation, all needs to be planned well across sectors, to ensure that investments in NbS contribute simultaneously to both, mitigation and adaptation. And it is critical that planning integrates with other objectives inclusive of compact city, healthy and age-friendly city, among others (N. Habib et.al., 2020) Because physical structures, industries, standards, governance, regulatory and educational institutions, and mindsets can’t change overnight, a holistic strategy and the collective will to fast forward implementation is most needed. Some of the below findings were described in a prior publication by the author (S. Rau, 2022) and updated with results from new literature and projects, especially on effectiveness evaluation and new methods applied.

Item Type:	Article
Uncontrolled Keywords:	risk-informed planning, advanced planning tools, sponge city, nature-based solutions, urban climate resilience
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences G Geography. Anthropology. Recreation > GF Human ecology. Anthropogeography H Social Sciences > HD Industries. Land use. Labor
Depositing User:	REAL CORP Administrator
Date Deposited:	25 Apr 2024 18:46
Last Modified:	25 Apr 2024 18:46
URI:	http://repository.corp.at/id/eprint/1080

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