**4. Results**

Results can be found in Table 6, which shows 14 elements whose average significance level is above 4 for Singapore, 13 elements for Hong Kong, and 14 elements for Hangzhou. For Singapore, the EP3 (*Noise Pollution*) is ranked as the lowest significance, while that for Hong Kong is EP1 (*Flood Risk Assessment & Management*) and for Hangzhou, it is EN2 (*On-site Energy Generation*).

Figure 1 demonstrates the differences in the significance level of each category for elements of attentions for enhancing urban resilience. *Innovation* is the highest priority for Singapore and Hangzhou, while *Material & Waste* is the highest priority for Hong Kong. This difference is echoed by socio-economic conditions. Singapore and Hangzhou placed a much higher priority on innovations for urban development and managemen<sup>t</sup> through their various governmental policies. Hangzhou is recently considered as a digital city, which takes innovative technologies, e.g., cloud computing and artificial intelligence, to advance urban governance and solve the serious problems of traffic jams. On the other side, Hong Kong is facing increasing problems related to the limited land for waste landfills; therefore, relevant elements in the *Material & Waste* category are prioritized. In addition, Singapore takes the highest priority in the categories of *Green Building & Green Transportation*, *Community* and *Innovation* among the three cities. Hong Kong takes the leading role in the categories of *Energy*, *Water*, *Material & Waste*, *Environmental Planning* and *Economy* among the three cities. Hangzhou takes the leading role only in the category of *Governance* among the three cities.

Figure 2 demonstrates the significance level of each element of attentions for enhancing urban resilience in the three cities. This research defines the elements with an average significantly higher than 4 as key elements of attentions for enhancing urban resilience in the case city. Among the 14 significant elements for Singapore, WA1 (*Water Strategy*), MW2 (*Resource Management*), GBT4 (*Public Transport Facilities*), and CO1 (*Stakeholder Engagement, Feedback, & Evaluation*) are the elements of the three highest significance. MW1 (*Waste Management and Segregation*), EP10 (*Land Use*) and GBT3 (*Green Transport within District*) are the elements ranked with the three lowest significance. Among the 13 significant elements for Hong Kong, MW2 (*Resource Management*), MW1 (*Waste Management and Segregation*), and CO2 (*Public Awareness & Education*) are the elements of the three highest significance. MW4 (*Sustainable Construction for Infrastructure & Public Amenities*), GBT2 (*Green Urban Design Guidelines*), and I1 (*Green Features & Innovations*) are the elements ranked with the

three lowest significance. Among the 14 significant elements for Hangzhou, EP2 (*Adapting to Climate Change*), WA1 (*Water Strategy*) and EN3 (*Energy Management Plan & System*) are the elements with the three highest levels of significance. EP7 (*Conservation & Integration of Existing Structure*), EP10 (*Land Use*), WA5 (*Water Efficient Fittings for Infrastructure & Public Amenities*), EP8 (*Green & Blue Spaces within District*) and GBT2 (*Green Urban Design Guidelines*) are the elements with the two lowest levels of significance.

**Table 6.** The average significance level of preliminary indicators in Singapore, Hong Kong and Hangzhou.


Note: the average value above 4 indicates key elements of attentions of the case city.

**Figure 1.** Importance of each category of elements of attentions for enhancing urban resilience in the three cities.

## **5. Discussions**

The three cities have different key elements of attentions for enhancing urban resilience (see Figure 2). Although the elements EN1 (*Energy Efficiency for Infrastructure & Public Amenities*), WA1 (*Water Strategy*), MW2 (*Resource Management*), EP2 (*Adapting to Climate Change*), EP8 (*Green & Blue Spaces within District*), and I1 (*Green Features & Innovations*) have varying average significance, they are the common elements for all three cities. EN3 (*Energy Management Plan & System*), EP6 (*Self-sufficiency & Accessibility within District*), GBT3 (*Green Transport within District*), GBT4 (*Public Transport Facilities*), CO1 (*Stakeholder Engagement, Feedback, & Evaluation*), and CO3 (*Green Lease*) are the six significant elements emphasized by Singapore. By contrast, EN4 (*Site Planning & Building Orientation*) is the single significant element emphasized by Hong Kong, while WA5 (*Water Efficient Fittings for Infrastructure & Public Amenities*), EP7 (*Conservation & Integration of Existing Structure*), and GO2 (*Design Review*) are the three significant elements that Hangzhou emphasized. The following section will thoroughly discuss the identified key elements of attentions for enhancing urban resilience in the three cities.

In terms of *Energy*, *Energy Efficiency for Infrastructure & Public Amenities* is the common key element in the three cities. Previous studies determined that improving the energy efficiency of infrastructure and public amenities is useful for enhancing the ability of cities to cope with external disturbances, e.g., climate change and supply shortage. Energy efficiency is a huge concern of the three cities, which cannot produce sufficient energy by themselves. For example, Hangzhou proposed to replace existing buses in urban areas with new energy vehicles in the 2020 governmen<sup>t</sup> work report (A breakdown of key responsibilities in the 2020 governmen<sup>t</sup> work report). Singapore proposed integrated planning and sound governance to ensure secure, competitive and sustainable energy supply (Energising Singapore: Balancing Liveability and Growth). *Energy Management Plan & System* is the common element for Hong Kong and Hangzhou. An improved energy managemen<sup>t</sup> plan and systems can bring higher energy efficiency in the building operation and managemen<sup>t</sup> stage. This result reflects that Hong Kong and Hangzhou still have much room to improve the performance of their energy managemen<sup>t</sup> plans. Hong Kong also emphasizes *Site Planning & Building Orientation* in the *Energy* category. In a high-density city such as Hong Kong, the site planning and relevant building orientation affect whether natural resources, e.g., wind and light, may be sufficiently utilized, which further affects energy consumption in the construction and operation and managemen<sup>t</sup> stage. Hong Kong's building practices are regularly updated to fulfill international standards. For example, steel structures in Hong Kong are designed to be resilient to disasters. Therefore, Hong Kong should also pay due attention to optimizing site planning and building orientation to save energy.

With respect to the *Water* category, *Water Strategy* is the common key element in this category among the three cities. Singapore and Hong Kong are troubled by sufficient water for use because of their geographical constraints. Hangzhou is worried about the quality of water and formulates policies to cope with sewage water, flood and urban waterlogging, as well as further ensuring the water supply and saving water. Therefore, *Water Strategy*, or ensuring sufficient quality water, is important for the three cities. A series of measures were adopted to promote the water strategy. For example, Hangzhou implemented projects to ensure sufficient water resources (Hangzhou Disaster Prevention and Mitigation Action Plan). Hong Kong formulated Desalination-A Critical Element of Water Solution for the 21st Century. Singapore proposed to create a robust system to manage the impact of rising sea levels and changing weather with multi-functional water storage projects. Hangzhou also stresses the importance of *Water Efficient Fittings for Infrastructure & Public Amenities*, because its utilization efficiency of water for infrastructure and public amenities is still quite low compared to other cities. Hangzhou proposed to promote the construction of zero-direct sewage discharge areas and speed up the construction of flood control and drainage projects, such as the Bapu Pumping Station (A breakdown of key responsibilities in the 2020 governmen<sup>t</sup> work report).

With regard to the category of *Material & Waste*, *Resource Management* is the common key element among the three cities. Waste resource managemen<sup>t</sup> affects the material used and waste generated during the construction stage. All three cities are concerned with improving the managemen<sup>t</sup> of their resources to achieve more sustainability and resilience. Better waste resource managemen<sup>t</sup> enhances resourcefulness, redundancy and efficiency of the urban system, which can improve urban resilience. For example, Hong Kong proposed the "Hong Kong Blueprint for Sustainable Use of Resources 2013–2022" and "A Clean Air Plan for Hong Kong". *Waste Management and Segregation* and *Sustainable Construction for Infrastructure & Public Amenities* are two common key elements for Singapore and Hong Kong. Efficient waste managemen<sup>t</sup> can reduce the generation or increase the reuse of construction waste, which helps achieve sustainability. The *Sustainable Construction for Infrastructure & Public Amenities* is useful to provide critical support for resilient cities. For example, the Hong Kong governmen<sup>t</sup> ensures that the infrastructural environment is assessed and made disaster-resilient to a grea<sup>t</sup> extent [30]. Singapore proposed a new future city initiative which focused on advanced building methods, resilient infrastructure, new spaces and sustainable cities.

In terms of *Environmental Planning*, *Adapting to Climate Change* and *Green & Blue Spaces within District* are two common key elements in this category among the three cities. Hangzhou, which held the G20 meeting in 2016, actively promoted the "Paris Agreement" as soon as possible, to enhance the priority position of environmental sustainability in the structure and expedite the green financial development. China is promoting the implementation of the 2030 Sustainable Development Agenda program, and Hangzhou actively responds to the policy and strives to move forward. *Environmental Management System* is the common key element for Hong Kong and Hangzhou. This element emphasizes an improved environmental managemen<sup>t</sup> to achieve sustainability and resilience. *Land Use* is the common key element for Singapore and Hangzhou. Unlike the high-density utilization in Hong Kong, Singapore and Hangzhou still have room to improve their land use, to realize sustainability and resilience. *Self-sufficiency & Accessibility within District* is the distinctive key element for Singapore, a concern that is a natural response to the limited resources within the city. *Conservation & Integration of Existing Structures* is the distinctive key element for Hangzhou, which has many existing structures built throughout its long history. Therefore, the conservation and integration of existing structures are important to realize cultural sustainability and to better utilize existing resources. The conservation measures can further enhance the social cohesion with a common memory, improve social capital and further increase urban resilience.

Concerning the category of *Green Building & Green Transportation*, no common key element is found in the three cities. *Green Urban Design Guidelines* is the common key element for Hong Kong and Hangzhou. This result indicates a current lack of such guidelines. The respective governments should explore such issues and develop appropriate guidelines according to the local conditions. *Green Transport within District* and *Public Transport Facilities* are distinctive key elements for Singapore because of the dispersed distribution of housing in the city and the huge demand for transportation. Singapore made the "Land Transport Master Plan" and promoted a transit-oriented approach to development and planning, which aims to make public transport the preferred mode of transit, through improved connectivity and better services.

In the *Community* category, *Public Awareness & Education* is the common key element for Hong Kong and Hangzhou, thus reflecting the lack of direct guidelines to initiate resilient cities in these cities. Public education should be conducted to promote the public's awareness of resilient cities. For example, Hangzhou proposed to build a platform for urban safety publicity and education and promote the construction of a multi-functional base integrating urban disaster reduction and prevention, building fire safety, road traffic safety, occupational safety and health, and other real scene experiences, as well as practical operations to avoid disasters (Three-Year Action Plan of Hangzhou City to Create a National Demonstration City for Security Development (2018–2020)). *Stakeholder Engagement,*

*Feedback, & Evaluation* and *Green Lease* are distinctive key elements for Singapore. These concerns reflected the awareness of the importance of stakeholder managemen<sup>t</sup> and the green lease in Singapore.

The element of *Economic Impact* is not identified as a key element of attentions for enhancing urban resilience for the three cities. This meant that the economic issues are not that important compared with other indicators for the interviewees. The alternative interpretation is that the three cities have a sufficient budget to consider more than the economy in promoting resilient cities. In addition, *Design Review* is the distinctive key element in the *Governance* category in Hangzhou, a result indicating the comparatively low design quality and high concern for governmen<sup>t</sup> departments.
