GIS-Based Assessment of Photovoltaic and Green Roof Potential in Iași, Romania

With rapid growth of population and the increasing demands for higher living standards, the development of urban infrastructures and buildings are likely to increase the impervious surfaces in the river basin. Green roofs have a famous strategy in the sustainable urban development strategies in recent decades. Green roof is a viable means of increasing the amount of vegetation in urban cities, where the open space at ground level is limited but roof tops are largely unused yet remain impervious and contribute to storm water runoff. This paper is aimed to review comprehensively the types, components, and environmental benefits of green roofs to the sustainable urban development. Generally, green roofs provide a lot of advantages for example decreasing consumption of energy by reducing heating and cooling loads, increase building standards, provide aesthetic value and amenity, improves urban air quality, increase storm water runoff mitigation, decrease air temperatures, decrease noise in urban environments, support in urban storm water pollutant removal, and mitigate urban heat island effects. This paper also reviewed the development and application of green roofs in different countries. In conclusion, more implementation of green roofs in the urban city should be promoted in order to ensure the sustainability of the urban development.

Towards a green sustainable strategy for Mediterranean cities: Assessing the benefits of large-scale green roofs implementation in Thessaloniki, Northern Greece, using environmental modelling, GIS and very high spatial resolution remote sensing data

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.

<p>Concerns about the cooling requirements of buildings and negative health effects from heat exposure are increasing with the public’s awareness of climate change. Green roofs have been considered a powerful mitigative and/or adaptive tool to reduce negative impacts of heat. In fact, they can reduce summer indoor-temperatures, as evapotranspiration increases latent heat-flux from a building’s roof. The cooling effect seems to be small on outdoor air temperatures, according to past studies, although green roofs have other benefits in terms of biodiversity, carbon storage, improved building thermal performance and flood management. As the need for sustainable and climate resilient building designs becomes the norm in cities, it is important to assess the status of green roofs coverage and explore potential for future implementation. Accurate information on the prevalence and characteristics of existing green roofs is indeed required to estimate any effect of green roofs on outdoor and indoor temperatures, although this information is often lacking.</p><p>Surveying Greater London, we identified existing green roofs and estimated the potential for buildings to be retrofitted with green roofs. Existing green roofs were identified using automated classification of aerial and satellite imagery. Potential for retrofit is assessed using a geospatial database of building characteristics, together with a digital surface model.</p><p>The current total green roof area in Greater London is around 1.5 square kilometres (around 0.5% of built area). We estimate that retrofitting existing suitable buildings could add another 3 square kilometres, corresponding to around 2% to the built area in Central London, and around 1% outside Central London. Existing green roofs appear mainly on new buildings rather than being retrofitted, and mainly occur on office and commercial buildings in Central London and residential blocks in redeveloped areas. Potential for retrofit may be highest in the borough of Tower Hamlets, largely on residential blocks with flat roofs.</p><p> This work has direct relevance to sustainable planning policy, especially the <em>London Plan Overheating and cooling policy</em>, and will enable modelling of the building-stock and city-scale effects of green roofs.</p>

Green roofs provide a wide range of co-benefits, including reducing stormwater runoff, improving air and water quality, supporting biodiversity and decreasing energy consumption for heating and cooling. These features make green roofs essential for the sustainable development of smart, resilient cities. Despite extensive research on their benefits, adoption remains limited, largely due to unclear public perceptions and limited understanding of citizens' willingness to pay (WTP) for green roof installation and maintenance. Gaining insights into public interest and WTP is crucial for urban planners and policymakers to incorporate green roofs into future urban development plans.This study examines public perceptions of green roofs and other nature-based solutions (NbS) in Edinburgh, Scotland, and assesses residents' WTP for their adoption. A survey disseminated through social media platforms and in-person flyers yielded over 300 responses. The data were analysed to identify trends in awareness, interest and WTP, associated with different socio-economic and demographic indicators.Key findings reveal a high level of awareness about NBS and recognition of green roofs as effective solutions to major environmental challenges, such as high energy consumption, air quality issues, water retention and biodiversity loss. Many respondents expressed WTP for green roofs, particularly through council tax contributions for public infrastructure, though only 25% showed interest in installing a green roof on their own property. Barriers to adoption include unsuitable building conditions, high installation and maintenance costs, and limited knowledge about green roof implementation. More than half of respondents indicated that they felt as though their buildings were unsuitable for green roof installation or they were not in a place to make this decision (i.e. not the property owner or living in a shared block of flats where external features are managed by an external company). However, if these barriers were not present, there would be a preference for supporting green roofs on public and private spaces in cities.Additionally, a comparative analysis with findings from an affiliated study conducted within Mediterranean regions was conducted to identify potential cultural and economic factors influencing regional variations in WTP for green infrastructure in cities. Preliminary analysis demonstrates that the perceptions on the benefits of green roofs differ, driven by differing priorities and challenges associated with regional climatic conditions (i.e. passive cooling in Mediterranean regions versus heat retention and rainfall management in Edinburgh’s temperate oceanic climate).This study has implications for the adoption of green roofs within the UK and Europe, highlighting several barriers which need to be overcome before widespread adoption can be achieved.

The hydrological behaviour of extensive and intensive green roofs in a dry climate

Increasing urbanization, impervious space, and the impact of climate change are threatening the future of cities. Nature-based solutions, specifically urban green infrastructures, are seen as a sustainable strategy to increase resilience against extreme weather events, including the escalating occurrence of stormwater runoff flooding. Consequently, urban planners and decision-makers have pushed their efforts toward implementing green infrastructure solutions to reduce the impact of stormwater floods. Among others, green roofs help store water and decrease stormwater runoff impacts on a local scale. This research aims to investigate the effect of surface permeability and green roof implementation on reducing stormwater flooding and subsequently provide urban planners with evidence-based geospatial planning recommendations to improve urban resilience in Helsinki. First, we modeled the current impact of stormwater flooding using the Arc-Malstrom model in Helsinki. The model was used to identify districts under high stormwater flood risk. Then, we zoomed in to a focus area and tested a combination of scenarios representing four levels of green roof implementation, two levels of green roof infiltration rates under 40-, 60-, 80-, 100 mm precipitation events on the available rooftops. We utilized open geographic data and geospatial data science principles implemented in the GIS environment to conduct this study. Our results showed that low-level implementation of green roofs with low retention rates reduces the average flood depth by only 1 %. In contrast, the maximum green roof scenario decreased most of the average flood depth (13 %) and reduced the number of vulnerable sites. The proposed methodology can be used for other cities to develop evidence-based plans for green roof implementations.

Green roof effects on urban building surface processes and energy budgets

Rapid urbanisation and climate change have intensified the expansion of impervious surfaces and extreme rainfall events, heightening the risk of Urban Pluvial Floods (UPF). Therefore, this study aims to analyse Green Roofs (GR) as a Nature-Based Solution for UPF in Milan, Italy. The study utilises a GR dataset, which contains 53,519 data points, to identify potential places for GR installation within the municipal area of Milan [1]. Each item contains geographic coordinates and roof area. Moreover, the dataset also classifies the roofs into the type of structure, i.e., residential, industrial, and commercial buildings, etc. The Curve Number (CN) methodology in the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) Urban Flood Risk Mitigation model is employed to compute the flood maps [2]. First, a baseline scenario is simulated without the intervention of GR to serve as a reference. Three intervention approaches are then devised to evaluate the efficacy of the GR in reducing the UPF hazard with varying percentages of the GR dataset implemented. Starting from 5% implementation and incrementally increasing up to 100%. Random iteration (ITE) approach is conducted initially. Second, iterations employ roofs with the highset area (AR). Finally, areas with the highest water depth (WD) are targeted first for the GR implementation. The model uses Copernicus Land Use/Land Cover data (LULC) [3] and NASA Soil Hydrological Group (SHG) data [4] as inputs. Moreover, the model also requires a CN table derived from a literature review. The baseline scenario without GR integration was compared to the scenarios to assess reductions in floodwater depth and affected area. The Probability Density Function (PDF) plot of the results indicated a randomised decrease in water depth across the ITE scenario. In contrast, the AR scenario demonstrated a more significant decrease in water depth during the initial stages. According to the PDF results, the WD scenario had better results. Therefore, to complete the risk assessment, the results from the WD scenario were integrated with exposure and vulnerability information. The JRC vulnerability function for residential buildings was used to complete the risk assessment. Although the analysis provided some useful insights, a comprehensive Cost-Benefit analysis is necessary to account for implementation and maintenance costs, with reduced risk and Average Annual Losses serving as the primary benefit for optimising the resource allocation. Finally, the study has some limitations, including the assumption of uniform rainfall across the municipal area and the model’s exclusion of water propagation effects.Keywords: Urban Flood Risk, Green Roofs, Nature-Based Solutions, Risk-based design, Curve Number method[1]        Unità Open Data, ‘Potential green roofs in Milan’, Comune di Milano, 2016 (updated 2021-11-10), accessed 2025-01-13, http://data.europa.eu/88u/dataset/ds1446[2]        Stanford University et al., “Natural Capital Project InVEST 3.14.2.” Accessed: Sep. 02, 2024. [Online]. Available: https://naturalcapitalproject.stanford.edu/software/invest[3]        Copernicus, “CORINE Land Cover 2018 ,” 2024. Accessed: Sep. 02, 2024. [Online]. Available: https://doi.org/10.2909/71c95a07-e296-44fc-b22b-415f42acfdf0[4]        NASA, “Global Hydrologic Soil Groups (HYSOGs250m) for Curve Number-Based Runoff Modeling,” 2020. Accessed: Sep. 02, 2024. [Online]. Available: https://cmr.earthdata.nasa.gov/search/concepts/C2216864285-ORNL_CLOUD.html 

Towards green roof implementation: Drivers, motivations, barriers and recommendations

THE EFFECT OF SUBSTRATE DEPTH AND SUPPLEMENTARY WATERING ON THE GROWTH OF NINE HERBACEOUS PERENNIALS IN A SEMI-EXTENSIVE GREEN ROOF

Green roofs have gained attention as sustainable solutions to urban environmental challenges. This comprehensive study delves into the multifaceted aspects of green roofs, including their environmental, economic, and social impacts. The research design incorporated data collection from diverse sites and rigorous analysis to provide a holistic perspective. The study reveals that green roofs exhibit promising benefits in terms of temperature regulation, energy efficiency, stormwater management, and biodiversity promotion. Economic analysis indicates long-term cost savings and ecological advantages, while the social and cultural dimensions shed light on the positive influence on human well-being. This research also delves into policy and regulation aspects, highlighting the importance of supportive measures for wider green roof adoption. Through case studies, practical insights are shared, emphasizing the real-world potential of green roofs. In conclusion, this study recommends the integration of green roofs in urban planning, emphasizing the need for informed decision-making and policy frameworks to unlock the full potential of green roofs in creating sustainable and resilient cities Green roofs have been heralded as a “sustainable building practice” in cities throughout the world as one response to mounting environmental stresses. A range of stressors plus erosion of aesthet-ics and human well being in urban areas have initiated policies and practices often with incentives to develop green infrastructure such as green roofs. They provide a suite of public and private benefits most of which map onto services generally provided by the ecosys-tem. Green roof development imbeds in environmental design pro-cesses and is constrained by both human and environmental factors. As relatively small, simple, anthropogenic ecosystems, green roofs relate to several existing conceptual and applied ecological ideas. Understanding and applying from ecology and ecosystem studies, ecological engineering, managed ecosystems, construction ecology, urban ecology, landscape ecology, restoration ecology, reconcilia-tion ecology, soil ecology and community ecology show green roof ecosystems can be created to cycle energy and nutrients. Further-more, green roofs can be constructed to model an ecosystem and may provide a setting for testing ecological concepts. This book takes an ecosystems approach to describing a large number of inter-actions on green roofs placing them in the total human ecosystem.

This study aims to investigate the integration of renewable energy systems into urban planning, a crucial strategy for sustainable urban development. Employing a mixed-methods research design, the study combines quantitative analysis of data from ten cities and qualitative insights from semi-structured interviews and case studies of Copenhagen, Freiburg, and Masdar City. The quantitative analysis reveals a significant positive relationship between policy support and renewable energy adoption, indicating that cities with robust policy frameworks are more likely to achieve higher shares of renewable energy. Technological advancements and community engagement emerged as critical enablers, with innovative renewable energy technologies and active public participation contributing to the successful implementation of renewable energy projects. The case studies provide in-depth examples of best practices and innovative approaches to integrating renewable energy systems. Challenges such as high upfront costs, variability of renewable energy sources, and regulatory barriers are identified, alongside recommendations for addressing these issues through supportive policies, financial incentives, and technological innovations. The findings highlight the importance of coordinated efforts across technological, economic, policy, and social dimensions to promote renewable energy integration in urban areas. This study offers valuable insights for policymakers and urban planners, emphasizing the need for comprehensive strategies to achieve sustainable and resilient urban development through the integration of renewable energy systems.

Influence of urban morphology on potential of green roofs in regulating local microclimate: A case study of Liège, Belgium

Green roofs and green walls layouts for improved urban air quality by mitigating particulate matter