Urban Sprawl and Rural Landscapes: Perceptions of landscape as amenity in Portland,Oregon

In the Portland, Oregon, metropolitan region, an urban growth boundary (UGB) was established in 1979 to protect farm and forest lands from urban encroachment. Most of the literature on the impact of Oregon's land-use legislation has been on the urban side of the issue—primarily the relative success Portland has had in containing urban sprawl. The landscape component of this rural transformation is typically considered only as a passive backdrop to urban expansion. Portland provides an excellent site to examine the relationship city-dwellers have to nearby agricultural areas. Rapid urban growth in the 1990s pushed suburban development to the edge of the UGB creating stark contrasts between urban and rural land uses in parts of the metropolitan area. This study examines the impact of the UGB on rural landscape change in Portland. We combine findings from land-use analysis and surveys of urban and rural residents to suggest ways to merge the amenity values of landscape with planning policy regarding the UGB.     

Using nighttime light data to estimate water evaporation inside buildings in China's urban areas

Urbanization has a great impact on urban evapotranspiration. Water evaporation inside buildings is an important part of urban water vapor resources and a crucial core of urban hydrological processes. The systematic studies on building water evaporation (BWE) are mostly the method of experimental monitoring. This study proposed a new method to simulate and estimate water evaporation flux inside buildings in urban areas. Based on the nighttime light data and urban per capita gross domestic product (GDP), a new modeling system was built to simulate the total BWE. Building area was calculated using the nighttime light data. And the BWE coefficient D_f was estimated according to the important indicator of economic development per capita GDP value. Then the water evaporation inside urban buildings and the spatial distribution of water evaporation inside buildings in typical cities could be obtained. The results showed that the total amount of water evaporation inside buildings in China's urban areas was 24.5 billion m³. Among the 31 provincial capitals in China, Shanghai had the largest BWE of 1.08 billion m³. The minimum water evaporation of buildings in Lhasa was 20.0 million m³. Studies of BWE can assess urban water budgets, support on-demand allocation of water resources, and provide a fundamental understanding of the relationship between water resources and energy heat island effects in urban areas.     

The urban growth machine goes South: Conditions and capacities for more sustainable place-building

Abstract

The prospects for global sustainable development are thoroughly tied to the future of cities. Our goal is to better understand how cities actually get built and with what substantive consequences. Beyond designing and implementing public policy tools, this requires a better understanding of the underlying political economy of urban place-building. Beginning with the ideal type of the urban growth machine, we outline frameworks for analysing both the ‘conditions for urban place-building’ and the ‘capacities for sustainable urban place-building’. We apply these in the Chilean context by examining general features of the urban political economy and then specific development exemplars from the urban region of Valparaíso. We outline frameworks for further comparative work.     

Characteristics of Urban Natural Areas Influencing Winter Bird Use in Southern Ontario,Canada

Characteristics of urban natural areas and surrounding landscapes were identified that best explain winter bird use for 28 urban natural areas in southern Ontario, Canada. The research confirms for winter birds the importance of area (size) and natural vegetation, rather than managed, horticultural parkland, within urban natural areas as well as percent urban land use and natural habitat in surrounding landscapes. Alien bird density and percent ground feeding species increased with percent surrounding urban land use. Higher percent forest cover was associated with higher percentages of forest, bark feeding, small (<20 g) and insectivorous species. Natural area size (ha) was related to higher species richness, lower evenness and higher percentages of insectivorous, forest interior, area-sensitive, upper canopy, bark feeding, and non-resident species. Higher number of habitat types within natural areas and percent natural habitat in surrounding landscapes were also associated with higher species richness. Common, resident bird species dominated small areas (<6.5 ha), while less common non-residents increased with area, indicative of a nested distribution. Areas at least 6.5 ha and more generally >20 ha start to support some area-sensitive species. Areas similar to rural forests had >25% insectivores, >25% forest interior species, >25% small species, and <5% alien species. Indicator species separated urban natural areas from rural habitats and ordination placed urban natural areas along a gradient between urban development and undisturbed, rural forests. More attention is needed on issues of winter bird conservation in urban landscapes.     

面向城市管理的城市建筑存量研究综述

城市建筑存量研究是为适应当前城市管理的需要而出现的理论研究,与国家制定的城市可持续发展战略具有内在一致性。本文对城市建筑存量的概念进行解析,全面阐述了城市建筑存量研究的意义,概述了城市建筑存量研究的系统边界、内涵和研究方法等,总结了城市建筑存量研究的三大领域：城市建筑存量时空演变及影响因素研究、城市建筑废弃物资源化开发潜力分析研究和城市可持续管理决策支持系统开发的研究现状。目前城市建筑存量理论体系尚不够完善、定量工具和基础数据库严重缺乏,对于城市决策支持不足,未来应在城市建筑存量时空演变及环境影响分析、开发融合多学科交叉及新技术应用的分析方法和辅助城市可持续管理决策三个领域加强和深化研究。     

Civic modes of greening the city? Urban natures in-between familiar engagement and green critique

ABSTRACT

In this article, we deploy the loosely bounded phenomenon of “urban green communities” – in the shape of urban gardening, beekeeping, food collectives, biodiversity enhancement, tree planting and kindred citizen-based group practices towards urban greening – in order to probe the wide variations in modes of civic engagement with urban sustainability politics. As such, we explore the conceptual gaps opened up in-between everyday lifestyle politics, green social movements and critiques of neoliberal urban political economies, by leveraging a novel and fine-grained conceptualization of civic and place-based material participation built from pragmatic sociology. The work of Laurent Thévenot on regimes of engagement, in particular, allow us to trace translations in-between the familiar attachments and the public critiques undertaken by urban green communities in ways that expand the frame on socio-material politics relative to current research conversations. Empirically, we leverage this re-conceptualization as part of a comprehensive digital mapping exercise set in Denmark, in which we trace core patterns and differences in modes of urban-green politics at the level of everyday citizen practices and group interaction styles across a diversity of urban green communities. Having identified six such civic modes of urban greening and specified their group styles of engagement, we end by discussing the implications of our findings for questions of care, justice and democracy in sustainable city-making.     

城市群的生态研究方向:城市群落学解析

城市群落是若干城市在共同的生境条件下通过竞争、共生等生态行为所形成,并与环境相互作用的城市群体,是具有协同进化、演替等生态功能的有机体.运用群落生态学的理论、方法对群落中城市种群间的关系、城市群落的结构特征及城市群落演替等方面进行研究,试图探求促进城市群落持续发展的规律.首先界定城市群落、城市群落学等相关概念,构建城市群落学理论框架;其次对比分析了生物群落与城市群落的特征和生态功能上的相似性和差异性;最后阐述了有关城市群落的种群组成、种间关联、群落结构及群落演替的研究内容,并提出了相应的城市群落研究方法.从生态学角度来看城市问题,借鉴群落生态学的原理和研究方法来认识城市群的发展,是"回归自然"的城市发展观点,有利于促进城市群落功能的发挥,推动城市群落向特定的方向演替.     

论体育与城市的整体发展

体育作为社会的一个重要组成部分,在现代城市的发展中起着自己特殊的作用,体育与城市文化、城市人口素质、城市环境建设、城市经济存在共融和协调发展的关系.     

城市蔓延、私人交通与雾霾污染

本文选取中国280个地级市2009—2018年的面板数据为研究样本,探究城市蔓延与雾霾污染之间的作用机制。以私人交通为门槛变量,考察城市蔓延对雾霾污染的门槛效应。研究结果表明：(1)城市蔓延对雾霾污染的影响呈现出先降后升的U形曲线特点;(2)私人交通对雾霾污染的影响表现为倒U形的曲线特征,即随着私人交通发展水平的提高,雾霾污染呈现先增后减的趋势;(3)城市蔓延对雾霾污染的影响存在双重门槛效应,当私人交通的门槛值小于第一个门槛值(e^11.6130=110 525辆)时,城市蔓延会加剧雾霾污染;当私人交通的门槛值介于第一个门槛值和第二个门槛值(e^12.2473=208 417辆)之间时,城市蔓延对雾霾污染的影响系数为正,但未通过显著性检验;当私人交通跨过第二个门槛值时,城市蔓延水平的提高有助于抑制雾霾污染。研究城市蔓延、私人交通与雾霾污染这三者之间的关系对于促进城市的健康可持续发展具有重要的意义。     

Urban sharing in smart cities: the cases of Berlin and London

ABSTRACT

Addressing urban sustainability challenges requires changes in the way systems of provision and services are designed, organised and delivered. In this context, two promising phenomena have gained interest from the academia, the public sector and the media: “smart cities” and “urban sharing”. Smart cities rely on the extensive use of information and communications technology (ICT) to increase efficiencies in urban areas, while urban sharing builds on the collaborative use of idling resources enabled by ICT in densely populated cities. The concepts have many similar features and share common goals, yet cities with smart city agendas often fail to take a stance on urban sharing. Thus, its potentials are going largely unnoticed by local governments. This article addresses this issue by exploring cases of London and Berlin – two ICT-dense cities with clearly articulated smart city agendas and an abundance of sharing platforms. Drawing on urban governance literature, we develop a conceptual framework that specifies the roles that cities assume when governing urban sharing: city as regulator, city as provider, city as enabler and city as consumer. We find that both cities indirectly support urban sharing through smart agenda programmes, which aim to facilitate ICT-enabled technical innovation and emergence of start-ups. However, programmes, strategies, support schemes and regulations aimed directly at urban sharing initiatives are few. We also find that Berlin is sceptical towards urban sharing organisations, while London took more of a collaborative approach. Implications for policy-makers are discussed in the end.     

Modeling Urban Growth Effects on Surface Runoff with the Integration of Remote Sensing and GIS

A methodology is developed to relate urban growth studies to distributed hydrological modeling using an integrated approach of remote sensing and GIS. This linkage is possible because both studies share land-use and land-cover data. Landsat Thematic Mapper data are utilized to detect urban land-cover changes. GIS analyses are then conducted to examine the changing spatial patterns of urban growth. The integration of remote sensing and GIS is applied to automate the estimation of surface runoff based on the Soil Conservation Service model. Impacts of urban growth on surface runoff and the rainfall–runoff relationship are examined by linking the two modeling results with spatial analysis techniques. This methodology is applied to the Zhujiang Delta of southern China, where dramatic urban growth has occurred over the past two decades, and the rampant urban growth has created severe problems in water resources management. The results revealed a notably uneven spatial pattern of urban growth and an increase of 8.10 mm in annual runoff depth during the 1989–1997 period. An area that experienced more urban growth had a greater potential for increasing annual surface runoff. Highly urbanized areas were more prone to flooding. Urbanization lowered potential maximum storage, and thus increased runoff coefficient values.     

Applying the methods of image evaluation and spatial analysis to study the sound environment of urban street areas

One important aspect of the urban environment is its sound environment, in which the sound environment of street areas plays a significant role. In this research, we employed methods of subjective image evaluation and spatial analysis of soundscape formation, in studying the sound environments of urban street areas. In Saga City, Japan, we analysed the structure and main sound components of urban street areas, as well as the sound pressure levels through on-site investigation. Through image evaluation, we obtained people's ratings of each sound component in terms of “preference” and “congruence”. Simultaneously, we interviewed people on site for their evaluation of the sound environment using semantic differential profiles. Lastly, we performed a spatial analysis of the site, identifying the different types of street sound environment and their characteristics using cluster analysis, as well as noting the interaction of auditory image and visual factors. The methods presented by this research can help us understand the sound environment of urban street areas more comprehensively and vividly, and to point out a unique direction in the research of urban sound environment as well as the planning of urban street areas.     

From Rio to Johannesburg and Beyond: A long and winding road

This paper analyses the evolution of urban form in two North American metropolitan regions (Portland and Toronto) and asks how more sustainable regional form might come about in the future in these and other urban areas. In the past, dominant patterns of urban form have emerged in such regions at different historical periods. These morphological phases include mid 19th-century grids, streetcar suburb grids, garden suburbs, automobile suburbs and New Urbanist neighbourhoods (which have only recently made an appearance and may or may not become widespread). Judging by the performance of past types of urban morphology, five design values appear particularly important for more sustainable urban form in the future: compactness, contiguity, connectivity, diversity and ecological integration. Although these principles were not well supported by 20th-century development, contemporary movements such as the New Urbanism and Smart Growth re-emphasise them. The example of these two regions indicates that, in the absence of new technological, economic or geographical forces, public sector institutions and urban social movements represent the most likely means to bring about new, more sustainable types of urban form.     

URBANIZATION INFLUENCES ON AQUATIC COMMUNITIES IN NORTHEASTERN ILLINOIS STREAMS1

ABSTRACT: Biotic indices and sediment trace element concentrations for 43 streams in northeastern Illinois (Chicago area) from the 1980s and 1990s were examined along an agricultural to urban land cover gradient to explore the relations among biotic integrity, sediment chemistry, and urbanization. The Illinois fish Alternative Index of Biotic Integrity (AIBI) ranged from poor to excellent in agricultural/rural streams, but streams with more than 10 percent watershed urban land (about 500 people/mi²) had fair or poor index scores. A macroinvertebrate index (MBI) showed similar trends. A qualitative habitat index (PIBI) did not correlate to either urban indicator. The AIBI and MBI correlated with urban associated sediment trace element concentrations. Elevated copper concentrations in sediment occurred in streams with greater than 40 percent watershed urban land. The number of intolerant fish species and modified index of biotic integrity scores increased in some rural, urbanizing, and urban streams from the 1980s to 1990s, with the largest increases occurring in rural streams with loamy/sandy surficial deposits. However, smaller increases also occurred in urban streams with clayey surficial deposits and over 50 percent watershed urban land. These data illustrate the potentially complex spatial and temporal relations among biotic integrity, sediment chemistry, watershed urban land, population density, and regional and local geologic setting.     

Water-sensitive Urban Planning: Protecting Groundwater

Sustainable development requires the promulgation of guidelines for urban planning which consider the effects of the built environment on water resources. In this context, our paper focuses on the effects of urban development on the quantity and quality of rainwater which infiltrates into the soil on its way to recharge the aquifer. The paper includes: identification of the state of knowledge regarding the effect of urban development on runoff and infiltration; a case study-estimation of the effect of certain patterns of urban development in an Israeli neighbourhood,together with an option for mitigating them by relatively simple and inexpensive means; presentation of the components of urban planning which influence runoff and infiltration; and proposals for continuing research in this area which has been relatively neglected until recently.     

The deep city: cultural heritage as a resource for sustainable local transformation

ABSTRACT

The sustainable city of the future is typically envisioned as smart, creative and disruptive, assuming that urban and local sustainability is achieved through new technology and innovation. However, considering that the built environments of our cities and surroundings are highly durable, there is also a need to focus on how resources brought from the past – histories, artefacts and places – may be used for promoting urban sustainability. We label this a “deep city” perspective on urban and local transformation. By looking at Røros, a World Heritage Site in central Norway with a dense and historic wooden urban centre, we investigate how its heritage protection facilitates the maintenance of a compact urban centre. We hold that a shared sense of place – the deepness– may serve as a resource against unsustainable sprawl and mall-oriented development.     

Resilience to heat in public space: a case study of Adelaide,South Australia

During summer heatwaves, heat load exacerbates in urban heat islands (especially in hot climates) and threatens public life in cities. This paper examines the links between urban microclimates, outdoor thermal discomfort and public life through an exploratory case study. Heat resilience is highlighted as the ability of the space to support its normal activities when experiencing out-of-comfort temperatures. It also reports on the correlations between heat sensitive outdoor activities and urban greenery in three disparate case studies in Adelaide. Results indicate that necessary and optional activities start to decline after the apparent temperature reaches the threshold of 28?°C–32 °C, while activities in public spaces with more urban greenery show higher resilience to heat stress. Research findings propose heat resilience as a quality indicator in public space and support the application of urban greenery to make urban settings more resilient to heat stress.     

URBAN IMPACTS ON PHYSICAL STREAM CONDITION: EFFECTS OF SPATIAL SCALE,CONNECTIVITY, AND LONGITUDINAL TRENDS1

ABSTRACT: An assessment of physical conditions in urban streams of the Puget Sound region, coupled with spatially explicit watershed characterizations, demonstrates the importance of spatial scale, drainage network connectivity, and longitudinal downstream trends when considering the effects of urbanization on streams. A rapid stream assessment technique and a multimetric index were used to describe the physical conditions of multiple reaches in four watersheds. Watersheds were characterized using geographic information system (GIS) derived landscape metrics that represent the magnitude of urbanization at three spatial scales and the connectivity of urban land. Physical conditions, as measured by the physical stream conditions index (PSCI), were best explained for the watersheds by two landscape metrics: quantity of intense and grassy urban land in the subwatershed and quantity of intense and grassy urban land within 500 m of the site (R²= 0.52, p > 0.0005). A multiple regression of PSCI with these metrics and an additional connectivity metric (proximity of a road crossing) provided the best model for the three urban watersheds (R²= 0.41, p > 0.0005). Analyses of longitudinal trends in PSCI within the three urban watersheds showed that conditions improved when a stream flowed through an intact riparian buffer with forest or wetland vegetation and without road crossings. Results demonstrate that information on spatial scale and patterns of urbanization is essential to understanding and successfully managing urban streams.     

Stability of self-reported favourite places and place attachment over a 10-month period

We investigated the reliability and stability of favourite place selections and evaluations of place attachment over a 10-month period. A simple random sample of 1273 respondents representative of the population of the two largest cities in Finland completed a mailed questionnaire. Reliability data was obtained in a second questionnaire (N = 427). We obtained five main favourite place types which were extensively managed natural settings (mainly urban woodlands), urban green spaces (mostly parks), waterside environments, exercise and activity/hobby areas, and indoor and outdoor urban areas. Sixty-four percent of the respondents in the second survey selected the same main favourite place type as 10 months earlier, which is more than what might be expected by chance. Extensively managed natural settings (mainly urban woodlands) and waterside environments were reselected most often. Indoor and outdoor urban favourite places had the lowest stability. We found evidence of people being more consistent in their attachment to natural favourite places than to urban favourite places. The findings lend further credence and credibility to earlier results concerning self-regulation and restorative experiences in favourite places.