Influence of Blue-Green and Grey Infrastructure Combinations on Natural and Human-Derived Capital in Urban Drainage Planning

Opportunities for Nature-based Solutions to contribute to Climate-Resilient Development Pathways

There is potential for Nature-based Solutions (NbS) to contribute to Climate Resilient Development (CRD) due to their integrated approach to mitigation, adaptation, and sustainable development. However, despite alignment between NbS and CRD's objectives, realization of this potential is not guaranteed. A CRD Pathways (CRDP) approach helps to analyze the complexities of the relationship between CRD and NbS, and a climate justice lens enables the identification of the multiple ways that NbS can support or undermine CRD by foregrounding the politics inherent in deciding between NbS trade-offs. We use stylized vignettes of potential NbS to examine how the dimensions of climate justice reveal the potential of NbS to contribute to CRDP. We consider tensions in NbS projects between local and global climate objectives, and the potential for NbS framing to reinforce inequalities or unsustainable practices. Ultimately, we present a framework that combines climate justice and CRDP in an analytical tool for understanding the potential for a NbS to support CRD in specific places.

Effects of perceived physical and aesthetic quality of urban blue spaces on user preferences–A case study of three urban blue spaces in Japan

Blue spaces, especially as important urban natural environments, provide various benefits. Despite the increasing number of relevant papers, most recent studies have focused on the association between blue space environmental quality and health, with limited research assessing the environmental quality and user preferences of urban blue spaces. This study establishes a relationship between preference and environmental quality by investigating visitors' perception of the environmental quality of urban blue spaces (physical and aesthetic). For this purpose, 296 questionnaires were collected from three urban blue spaces and a multiple linear regression analysis was executed. Model results indicated that six of nine environmental quality components had a significant effect on preference scores, with "harmony" demonstrating the highest and "visual spaciousness & diversity" the lowest effect. The current study shown that two scales provided were used to measure users' perceived levels of the physical and aesthetic quality of the Urban Blue Spaces were acceptable. These results can help in the effective use of these natural capitals in cities and provide guidance for the environmental design of blue spaces.

Studying the Effect of Blue-Green Infrastructure on Microclimate and Human Thermal Comfort in Melbourne’s Central Business District

Blue-green infrastructure (BGI) is defined as a strategically planned network of natural and semi-natural areas with other environmental features designed and managed to deliver a wide range of ecosystem services, which include microclimate regulation and enhanced human thermal comfort. While green infrastructure is widely known to be capable of mitigating the adverse effects of urban heat island, the effect of blue infrastructure to regulate thermal comfort is still poorly understood. This study investigates several blue-green-infrastructure (BGI) scenarios in the central business district (CBD) of Melbourne, Australia to assess their effects on microclimate and human thermal comfort. Three-dimensional microclimatic modelling software, ENVI-met, was used to simulate the microclimate and human thermal comfort. Physiological equivalent temperature (PET) was used to quantify the level of thermal comfort in selected research areas. Ten different scenarios were simulated, which included those based on green roofs, green walls, trees, ponds and fountains. The simulations suggest that green roofs and green walls in the high-rise building environment have a small temperature reduction in its surrounding area by up to 0.47 °C and 0.27 °C, respectively, and there is no noticeable improvement in the level of thermal perception. The tree-based scenarios decrease temperature by up to 0.93 °C and improve the thermal perception from hot to warm. Scenarios based on water bodies and fountains decrease the temperature by up to 0.51 °C and 1.48 °C, respectively, yet they cannot improve the thermal perception of the area. A deeper water body has a better microclimate improvement as compared to a shallow one. The temperature reduction in the fountain scenario tends to be local and the effect could only be felt within a certain radius from the fountain.

A SUDS Planning Decision Support Tool to Maximize Ecosystem Services

In the past years, alternative drainage approaches have emerged, such as Sustainable Urban Drainage Systems (SUDS), to prevent run-off and flooding impacts on the most vulnerable zones of the cities. These systems not only provide the benefit of water regulation but also promote other types of ecosystem services. Several studies have developed optimization tools to assist SUDS selection, location, and design. However, they do not consider a comprehensive set of ecosystem services (e.g., provision, regulation, cultural, and support services). This research proposes a flexible and adaptable methodology to incorporate SUDS in different stages of urban projects using a multi-objective optimization technique to minimize run-off, maximize ecosystem services and minimize cost. The methodology comprises four phases: (1) the preliminary analysis of ecosystem services potentially generated by each SUDS type, (2) the priority and opportunity index quantification, (3) the physical feasibility analysis, and (4) the multi-objective optimization tool implementation. The methodology was successfully applied to three different urban areas of Bogotá city (Colombia). Results evidence that the interaction of the budget constraints and the available area restrict the potential benefits of SUDS implementation. These results are helpful to support different urban planning stages.

Assessment of Blue and Green Infrastructure Solutions in Shaping Urban Public Spaces—Spatial and Functional, Environmental, and Social Aspects

Blue and Green Infrastructure (BGI) provide one of the key Nature Based Solution (NBS) approaches for sustainable stormwater management in cities, in conjunction with extending the scope of Ecosystem Services (ES). In both the process of planning and designing highly urbanized areas, the implementation of BGI is important for the improvement of living conditions and counteracting the negative effects of climate change. Based on the literature review, 19 BGI solutions were identified and then valorized in relation to the following three key aspects: spatial and functional, environmental, and social. The results of the assessment were derived using the scoring method and allowed for the identification of BGI solutions with a high, medium or low value for shaping sustainable urban public spaces. Using the potential of analyzed BGI solutions to improve the functioning and attractiveness of urban areas requires a comprehensive approach. Conscious planning and designing should use the knowledge presented to make the implementation of BGI solutions as effective as possible in relation to the above-mentioned aspects of shaping urban public spaces.