Potential for Urban Greening With Green Roofs: A Way Towards Smart Cities

Abstract

Abstract. Cities are experiencing increased pressure on social, economic, and environmental sectors due to the rapid urbanisation and increasing risk owing to climate change affecting the urban environment. Solutions such as green roofs are often discussed in the context of smart and sustainable cities as they present a multi-functional and solution-oriented approach to address these challenges. Green roofs become extremely relevant in the context of highly urbanised and compact cities where impervious surfaces are abundant. Therefore, in this paper, we analyse the potential of green roofs at a city scale with the help of parameters such as area and slope of the roof and structure of the building. We also identify the priority zones based on environmental and socio-economic parameters. The study is carried out in the city of Liege, Belgium. The results suggest that around 20% (350 hectares) of the total buildings in the city have the potential for developing green roofs. Moreover, the potential of green roofs is quite significant in terms of roof area in the priority zone. Due to significant socio-economic deprivation in high priority zones, implementation of green roofs might not be affordable. Buildings with larger roof sizes are mostly owned by companies or commercial establishments, thus, making larger roofs more relevant for retrofitting green roof. Thus, our approach can act as a preliminary decision-making tool for urban planners to analyse the potential of green roofs and prioritize them in deprived areas.

An Extension of Cityjson to Support Point Clouds

“…These characteristics are mandatory to determine the potential of urban greening with green roofs. Urban green infrastructures impose a slope lesser than 5° and a minimum area of 10 square meters (the area can be obtained by projecting points and meshes on the horizontal plane and determining their minimal bounding box to within a factor of the slope) (Joshi et al, 2020). As a result, it provides preliminary results for the small part of miss-generated roofs (of the order of a few percent of the dataset).…”

A Green Roof Case Study in the Urban Context of Milan: Integrating the Residential and Cultivation Functions for Sustainable Development

“…According to the research conducted by Joshi M.Y. et al [4], around the 20% of the existing building roofs in Liege, Belgium, are capable of being turned into green roofs-the research considered the structural conditions, slopes, dimensions, and the necessity of green areas into specific compartments of the existing buildings of the city. From a more general view, it is possible to assume that the percentage of suitable roofs can be increased by diminishing the number of limits and considering major structural interventions to allow for the biggest number of roofs to this transformation.…”

“…This research and its highlighted results suggest the importance of investigating the topic. The buildings of the city of Milan that could be subjected to this kind of transformation should be further explored; following the research conducted by Joshi et al [4], future investigations could focus on the structural limitations applied to existing buildings while acknowledging that, as shown by this case study, all building roofs could be turned into green ones if subjected to the necessary structural adjustments. Consequently, the exact amount of CO 2 emissions that a green roof, like the case study one, would be able to absorb should further be investigated.…”

“…This transformation, encouraged by the city project "Milano Clever Cities", will contribute to a major program of achieving a rise of green coverage within the city of the 625% in the next 10 years. Given all the benefits [1,[3][4][5] that come from the transformation of existing buildings' roofs into green ones, this investigation concentrated on the analysis of a case study project that was applied in Milan: the analyzed master thesis proposal focused on the design of a compartmented supra-elevation that acted as a college for students and a green roof. The investigation considered all the steps that should be followed when designing a green roof and analyzed all the possible benefits and problems that can occur when adding an extra level to an existing building.…”

“…"Overall, vegetation is shown to be a significant, if not essential, component of the urban environment, [thanks to which] improvements in quality of life are also exhibited at the community level" [2] (p. 1): this study therefore aimed to prove the advantages that could come from the application of a green roof mixed with a students' college on top of an existing building, implying that these can be applied at both the individual and community levels, as well as at the building and urban scales. Given all the benefits [1,[3][4][5] that come from the transformation of existing buildings' roofs into green ones, this investigation concentrated on the analysis of a case study project that was applied in Milan: the analyzed master thesis proposal focused on the design of a compartmented supra-elevation that acted as a college for students and a green roof. The investigation considered all the steps that should be followed when designing a green roof and analyzed all the possible benefits and problems that can occur when adding an extra level to an existing building.…”