Identifying enablers and barriers to the implementation of the Green Infrastructure for urban flood management: A comparative analysis of the UK and China

Abstract Climate change and urbanization are increasing the urban flood risk, which can cause adverse on socio-economic and environmental impacts. Green Infrastructure (GI) can reduce stormwater runoff and offer multiple benefits that have been initiated in the United Kingdom (UK) and China, namely Sustainable Urban Drainage Systems (SUDS) and Sponge Cities Program (SCP) respectively. Currently, the implementation of GI is restricted to small spatial (site specific) scale and facing several constraints such as financial investment and governance, that limited its fuller functions and potential. This study aims to identify the barriers and enablers for the adoption of GI by investigating SUDS and SCP in the UK and China, through twelve in-depth semi-structured interviews with stakeholders. Our results found that multiple benefits of the SUDS and SCP were identified, as the main enablers in both countries with reducing the stormwater runoff and alleviating peak discharge in the drainage system, also contributing to social well-being and climate adaptations. Some barriers found the current practices are facing challenges from financial, biophysical and socio-political circumstances in both cases. We conclude that it is beneficial to learn the comparative findings and experiences from both countries, which contributes to stakeholders for improving current GI practices, in prior to achieve more sustainable long-term deliverables.


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In recent years, the frequency, distribution and intensity of extreme weather 44 conditions, particularly short-term rainstorms, has been growing, leading to surface-   yet its recent use refers to a broader, conceptual approach to urban planning and 100 layout. Therefore, GI could also provide a range of other benefits in addition to flood 101 management.

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There is an increasing evidence that incorporating GI into urban designs can  Table 1 The identified multiple benefits of GI from various authors

Environmental benefits
The

Economic benefits
The provision of an 'enhanced environmental backdrop' to boost economic growth by attracting skilled workers and tourists to cities, and to boost products from the land and recreation and leisure ( for this study. 204 We attempted to alleviate the potential self-selection bias by selecting inter-

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Five nodes emerged through coding, summarising the raw data related to drivers, 252 barriers, strategies for overcoming barriers, stakeholders and comparisons. The de- and 7 were also able to discuss the UK issues as they had worked in both countries. mous words such as "driver", "enabler", "support" and "motivation". The frequency 260 of each enabler for the GI implementation mentioned by respondents from both coun-261 tries (see Table 3) found that multiple benefits are the main enablers for GI imple- Table 3 The frequency with which each enabler to the GI implementation was mentioned.

Multiple benefits
Surface water flooding control and management 12 Microclimate adaptation (environmental cooling, carbon emission reductions, improvements in water quality and biodiversity) mentation, as it was mentioned by 10 out of the 12 respondents.

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The primary barrier identified was the insufficient funding to support the GI 309 practices. It was mentioned frequently by ten of the respondents, and they empha-310 sised this issue using words such as "biggest" and "mainly". In fact, ten out of the respondents highlighted concerns about the lack of un-420 derstanding, knowledge, education, awareness, and expertise surrounding GI, which 421 is another key barrier to gaining support from local authorities and communities.

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The general public, industrial workers, engineers, contractors and designers were 423 mentioned as lacking the understanding of GI, which is also a barrier to its imple-424 mentation.     At a higher level, the political problems associated with changing legislation, 511 regulation, and planning guidelines were proposed by six of the respondents. For 512 instance, Respondent 1 mentioned that there was a need to: "improve a legal re-513 quirement to produce and deliver a GI strategy". Respondent 10 commented that 514 governments needed "to enable SUDS by improving our knowledge and make it manda-515 tory policy". Respondent 9 also suggested putting GI in the very early planning stage. Respondent 7 also believed that SCP projects are expected to generate a new 530 round of knowledge in the context of China, when given that, in the next two or 531 three years, but probably from 2020 onward, those experimental projects would be 532 evaluated, and then new policies and practices would be produced during this process.

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Another concern is to overcome financial problems, which was referred to by 534 all of the Chinese respondents as well as two of the UK ones. Adequate financial 535 resources and new financial mechanisms could help improve technical innovations. 536 Since maintenance has been one of the key barriers to GI implementation, any corresponding solution should include the design of low-maintenance GI in the early 538 planning stages.

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In addition, other ideas such as more transparent governance, stronger collab-540 oration, better early-stage planning and greater stakeholders involvement were also 541 suggested for improving the adoption of GI.  The planning process of projects is different as well. In China, it tends to be 562 top-down, with less public and stakeholder participation, meaning that projects tend 563 to get pushed through faster, though there is a corresponding lack of transparency.

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The UK, in contrast, tries to get more stakeholders involved in the project, which 565 helps to create more initiatives from the bottom up. However, the overall process is 566 slower.

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One UK respondent noted the governance system is different between the two 568 countries. The financial resources also vary between the two countries. One respondent 586 reflected that the tax system in the two countries is different in terms of generating 587 project funds from the taxpayers.

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"China has an advantage in that it is a heavy tax country compared to UK, In China, funding comes mainly from government grants, and PPP is an innova-602 tive financial mechanism for SCP that can attract more private investment. However, 603 this scheme is still at the pilot stage and is therefore not mature.   also be a limitation in ensuring the multiple benefits that can be achieved.

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In addition, the beneficiaries of GI need to be elucidated. The beneficiaries iden-630 tified in this study by the respondents (see Appendix A) are the public as the number 631 one priority, and others including the government/local authorities, local communi-632 ties, land developers and managers and the private sector such as water companies.

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The main beneficiaries of GI would be residential neighbourhoods, because GI would projects, which will then increase the confidence of decision-makers to take the the 732 initiative and their further potential engagement in the process more fully.

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The study also found that maintenance cost is a barrier to the implementation 734 of GI. This was particularly the case for the UK, which has a more decentralised 735 system than China. In some cases, confusion about who owns and maintains GI, or 736 poor coordination between those responsible for the work can also cause problems.  It is therefore imperative that the involved key stakeholders such as landowners, 743 developers and local authorities are educated as to the cost-benefits of GI in urban 744 cities, which is important for reinforcing funding support and for help in clarifying maintenance responsibility.

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In both countries, barriers to GI and sustainable water management extend be-   In both countries, multiple benefits were seen as the primary enablers of GI 816 rather than grey infrastructure. Stormwater runoff reduction and flood control were 817 the main functions, and the social effects and microclimate adaptation benefits that 818 GI can provide were also highlighted as important enablers. It is important that the 819 synergies between benefits provided by GI are well demonstrated and communicated 820 in both countries so that they are appreciated and not overlooked by decision-makers.

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This study also found that the most important barrier to increase the implemen-822 tation of GI was related to finance, both in upfront costs and maintenance. While the central Chinese government has ensured funding for GI, implementation is reliant on 824 public funding which may not be sustainable and could be holding back the delivery 825 of a number of SCPs. In the UK most funding must be found at local levels which 826 prevents large scale adoption of GI. Therefore, research into the monetisation of the 827 benefits of GI and identification of additional finance streams for GI implementation 828 is critical for both countries, and a shared research is also essential.

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In both countries, barriers to GI and sustainable water management span the  Finally, there have been many successful case studies and best practices about GI 848 in urban development. Thus, it is essential that international knowledge-sharing and UFUG126770 cooperation is increased through personnel training, technical consultation, expert 850 guidance to enhance more effective and wide-reaching joint partnerships.