Urban Porosity Research Articles

How urban form impacts flooding

Urbanization and climate change are contributing to severe flooding globally, damaging infrastructure, disrupting economies, and undermining human well-being. Approaches to make cities more resilient to floods are emerging, notably with the design of flood-resilient structures, but relatively little is known about the role of urban form and its complexity in the concentration of flooding. We leverage statistical mechanics to reduce the complexity of urban flooding and develop a mean-flow theory that relates flood hazards to urban form characterized by the ground slope, urban porosity, and the Mermin order parameter which measures symmetry in building arrangements. The mean-flow theory presents a dimensionless flood depth that scales linearly with the urban porosity and the order parameter, with different scaling for disordered square- and hexagon-like forms. A universal scaling is obtained by introducing an effective mean chord length representative of the unobstructed downslope travel distance for flood water, yielding an analytical model for neighborhood-scale flood hazards globally. The proposed mean-flow theory is applied to probe city-to-city variations in flood hazards, and shows promising results linking recorded flood losses to urban form and observed rainfall extremes.

Built environment influences on urban climate resilience: Evidence from extreme heat events in Macau

Systematic understanding of climate resilience in the urban context is essential to improve the adaptive capacity in response to extreme weather events. Although the urban built environment affects climate resilience, empirical evidence on the associations between the built environment and urban climate resilience is rare in the literature. In this study, urban heat resilience (HR) is measured as the land surface temperature (LST) difference in a given urban area between normal and extreme heat event, and it further explores the impact of two-dimensional (2D) and three-dimensional (3D) urban built environment features on HR. Using spatial regression, we find that solar insolation and water density are the dominant factors in determining land surface temperature. However, they do not appear to influence HR significantly. Results indicate that vegetation and urban porosity are crucial both in reducing LST and improving HR during extreme heat events. This study highlights the importance of 2D and 3D urban built environment features in improving HR to extreme heat events.

Porous Kirkenes: Crumbling Mining Town or Dynamic Port Cityscape?

The great number of actors in port city regions, such as port authorities, municipalities, national governments, private companies, societal groups, and flora and fauna, need to develop shared visions. Collaborative approaches that focus on combined values can help achieve long-term resilience and enable a sustainable and just coexistence of port and city actors within the same territory. However, the sheer focus on economic profit generated by port activities overshadows and ignores equally essential cultural, societal, and environmental values and needs. The lack of pluralities in planning and decision-making processes creates challenges for the cohabitation of the many actors and their interests within port-city regions. On the one hand, contemporary spaces in port cities cannot be classified and defined by traditional dichotomies anymore. On the other hand, the perception of spatial and institutional boundaries between port and city leads to a positivistic-driven definition of a rigid and inflexible, line-like interface physically and mentally separating the port from the urban activities and stakeholders, neglecting the inseparable character of many parts of our society. By investigating and re-imagining the future port-development plans within the historic mining town of Kirkenes, located around 400 km above the Arctic Circle in Northern Norway, the aim of this article is to explore and combine the concepts of negative and positive porosity and liminality and arrive at a renewed perception of the port cityscape, which can function as dynamic thresholds inbetween the multiple dualities and realities of various port and city actors. The article bridges the theoretical/conceptual sphere of urban porosity and the practical approaches of liminal design. By using Design Fiction as a tool for creating new, innovative, and pluralistic port city narratives, the article contributes to contemporary research that aims for imaginary, value-based, and history-informed approaches to designing future-proof, resilient, just, and sustainable port cities.

Urban porosity: a chronicle of spatial inclusion in Matonge, Brussels

ABSTRACT This article explores the concept of porosity as a metaphorical device to investigate the interplay between urban space and urban inclusion. It develops a diachronic case study of Brussels’ so-called “Congolese” or “African” neighbourhood of Matonge, drawing from urban analysis and fieldwork observations. Different historical and current modalities of city-making (including formal plans, urban projects and more “spontaneous” forms of urbanization) are examined in their respective impact on social exclusion and inclusion. This way, the aim is to reflect on the peculiar role of the built environment vis-à-vis socio-cultural diversity and inclusion. It will be argued that the notion of urban porosity allows to shed light on the intricate interplay between the formation of urban form and its subsequent capacity to “include” diverse forms of urban life. The case study of Brussels’ neighbourhood of Matonge thus advances porosity as a qualifier of space in view of urban inclusion.

Urban Porosity and Material Contamination: From Cholera to COVID-19 in Copenhagen

As a way of approaching the multiple ways a pandemic affects urban life, the authors suggest the notion of porosity. Through this, the article revisits the Danish capital during the cholera an typhus attacks, noticing how porosity is mobilized around contagious materials and bodies. Relating this to the COVID-19 outbreak, the article goes on to note how the porosity also can be seen in a temporal sense, stretching out from the fragile present to the promise of a new normality for the city and its metabolism.

Explaining Spatial Variations in Residential Energy Usage Intensity in Chicago: The Role of Urban Form and Geomorphometry

Understanding the spatial pattern of energy consumption within buildings is essential to urban energy planning and management. This study explores the spatial complexity of residential energy usage intensity, with a focus on urban form and geomorphometry attributes. Using spatial regression models, we find that while vegetation and isolation have more local impact on energy intensity, urban porosity and roughness length have consistent spillover effects on building electricity usage intensity in Chicago. In addition, these relationships are seasonally varied. The results highlight the importance of spatially explicit policies and clear urban design and form frameworks for improving urban energy efficiency.

Urban Physical Environments and the Duration of High Air Temperature: Focusing on Solar Radiation Trapping Effects

Urban heat island effects, which are the phenomenon wherein higher ambient air temperatures are measured in cities than in rural areas, have worsened urban thermal environments over the past decades. This study aims to analyze the effects of urban physical environments on the duration of high air temperature, using climate data collected from 217 Automatic Weather Stations in Seoul, Korea. In order to specify radiation trapping effects, interaction effects between sky view factors (SVF) and albedo values were analyzed using multiple regression analysis. The results indicate that increases in commercial and traffic areas lead to longer durations of high air temperature and that high urban porosity shortens the duration of high air temperature by improving urban ventilation. This study also indicates that the duration of high air temperature has a negative association with SVF; however, an analysis of interaction effects indicates that high-albedo materials diminish the positive effects of high SVF largely because of radiation trapping effects. These findings suggest that urban ventilation paths, high SVF, and materials with an appropriate albedo value play important roles in improving thermal comfort conditions, such as the duration of high air temperature.

An indicator of urban morphology for landscape planning in Lombardy (Italy)

PurposeThe spatial development of urban areas affects the characteristics of landscape as well as people’s aesthetic perception of it. Specifically, sprawl results in an urban morphology which is diametrically opposed to the compact city model and which assumes several kinds of patterns: for example “striped”, “ribbon” or “leapfrogged” urban development. Assessing urban morphology in spatial terms is crucial to urban policy, while landscape metrics are the key to a comprehensive understanding of different urban development patterns. The purpose of this paper to design and test an urban morphology indicator (UMI) for the Lombardy Regional Landscape Plan.Design/methodology/approachThe paper describes an UMI that can be used to identify the heterogeneity of built-up patterns according to urban porosity, fragmentation and patch shape. This UMI is a result of Esri ArcGIS 10.3 “grouping analysis” which works by applying a spatial statistical metric for clustering geometries in a given geographical area.FindingsMorphological analysis was used in regional urban development policies with a view to minimising impact on surrounding ecosystems and preserving the natural environment and landscape. It defines 28 different urban morphology patterns in the region, which are divided into systems, polarities and urbanised units.Originality/valueThe proposed methodology differs from those traditionally used in qualitative/descriptive landscape planning and supports the identification of morphological features with quantitative statistical and spatial data, allowing a fine-scale assessment of complex metrics.

The third space between land and water

The essay concentrates on the topic of water as a significant presence of natural and urban landscapes starting from its “mutable” and “dynamic” characteristic assumed as a crucial moment in the search for technological solutions regarding the “resilient vision” that conceptually and operationally is changing the consolidated defensive approaches. Going over the idea of the project as a post-catastrophe “restoration”, new hazard-specific site-specific strategies are tracing their way, characterized by the idea of a border as an “interactive edge”, like a third space , defining open and flexible bonds that shape new “Urban porosity”. Waterfronts and quays become resilient spaces capable to adapt and maintain a “dynamic stability” in relation to the natural actions.

Brazilian urban porosity: treat or threat?

Urban areas have spatial discontinuities, such as disconnected neighbourhoods, brownfield areas and leftover places. They can be captured by the metaphor of urban porosity. This paper aims to highlight the potential social consequences of urban porosity by creating a ‘porosity index’. The authors argue that these areas can provide capacity for flexibility, fluidity and absorption in major cities, but that they can also be a source of fragmentation, disconnection and isolation between different social groups, eroding the adaptive capacity of metropolitan systems. Porosity may thus have both positive and negative influences on the resilience of urban systems. Brazil's rapid process of urbanisation over the last 50 years shows both these sides of porosity, which create treats and threats for its urban systems. This paper develops an analytical framework within which to study how porosity manifests itself in Brazilian metropolises, which helps to identify porosity in the context of urban growth and decline. It uses statistical data from Brazilian Institute of Geography and Statistics relating to 12 Brazilian metropolises to generate the proposed porosity index. Additionally, the paper discusses the added value of the concept of urban porosity in addressing urban resilience and briefly elucidates the issues and opportunities caused by discontinuities in the urban fabric in Brazil's metropolises.

스티븐 홀의 복합 프로젝트에 나타난 도시 다공성(多孔性:porosity) 접근 방식과 계획적 특성

In the recent complex projects of Steven Holl, it tends to appear that phenomenological approaches in Holl's architecture are extended to the urban scale and urban porosity has been represented. This could be led by long period's experiments about porosity and architectural application of Menger's Sponge theory. Along with this, multi complex projects in Steven Holl's architecture were successfully accomplished representing various characteristics of urban porosity. Therefore, this study aims to find out Steven Holl's approaches and planning characteristics based on urban porosity and with this, to review architectural and urban values. The results are as follows. Firstly, in the formal approaches, they showed that typological analysis referenced from the city with variously presenting urban porosity. Secondly, in the connecting way among the masses, connecting bridges with porosity were represented. Thirdly, phenomenological spaces were converged to the realm of urban environmental publicity connecting with the urban environmental issues.