Impact of Urban Sprawl on Water Quality in Eastern Massachusetts,USA

A study of water quality, land use, and population variations over the past three decades was conducted in eastern Massachusetts to examine the impact of urban sprawl on water quality using geographic information system and statistical analyses. Since 1970, eastern Massachusetts has experienced pronounced urban sprawl, which has a substantial impact on water quality. High spatial correlations are found between water quality indicators (especially specific conductance, dissolved ions, including Ca, Mg, Na, and Cl, and dissolved solid) and urban sprawl indicators. Urbanized watersheds with high population density, high percentage of developed land use, and low per capita developed land use tended to have high concentrations of water pollutants. The impact of urban sprawl also shows clear spatial difference between suburban areas and central cities: The central cities experienced lower increases over time in specific conductance concentration, compared to suburban and rural areas. The impact of urban sprawl on water quality is attributed to the combined effects of population and land-use change. Per capita developed land use is a very important indicator for studying the impact of urban sprawl and improving land use and watershed management, because inclusion of this indicator can better explain the temporal and spatial variations of more water quality parameters than using individual land use or/and population density.     

The emergence of 'smart growth' intensification in Toronto: environment and economy in the new official plan

There has been a recent popularization of 'Smart Growth' planning in North American cities. Based upon the aim to decrease the impacts of sprawled regional development on the natural environment, a focus of Smart Growth planning is the intensification of both population and physical development in existing urban areas. Faced with the creation of a new Official Plan for the City of Toronto, municipal planners have chosen urban intensification as the vision for planning in Toronto over the next thirty years. This paper examines the nature of intensification planning in Toronto through an analysis of the language of urban intensification found in the Official Plan vision report. Within this report, emphasis is placed upon the role of intensified development and compact population growth as a solution to the environmental problems of urban sprawl. This paper argues that the environmental aspects of intensification provide a more acceptable public rationale for future intensification processes in Toronto; moreover, that the main rationale for intensification in Toronto is not to solve regional sprawl but to create compact urban districts in order to enhance the economic and physical revitalization of the city. The language of intensification in the Official Plan vision report suggests that urban intensification, particularly in Toronto's downtown core, is a strategy for the development of more 'livable' and vibrant residential and commercial areas. The emphasis on intensified development is geared towards the attraction and maintenance of private investment and skilled labour and is a central part of the City of Toronto's vision of economic growth.     

Impact of land use and land cover changes on the ambient temperature in a middle scale city, Takamatsu, in Southwest Japan

There is a lack of information on urban heat island impact on the thermal environment due to low populated urban sprawl, although densely populated urban sprawl impact has been identified by several researchers. The Takamatsu area has recently developed in a low populated urban sprawl style without any increase in population. This paper examined the impact of a low populated urban sprawl on the thermal environment through an analysis of the last 30 years data set and investigated the contribution of vegetation fraction and population density to the temperature trend. As a consequence, it was shown that one of the most significant causative factors of temperature increase is an expansion of non-vegetated area even without population growth. This result implied that vegetated zones should be maintained in urban areas in order to realize sustainable urbanization.     

Growth Management in the Vancouver Region

The Vancouver Region is widely recognised as one North American jurisdiction where strong growth management plans and policies have been put in place in order to control urban sprawl. While many authors have lauded the region for its good planning intentions, there has been little in the way of assessment of actual performance. This paper attempts to identify some quantitative growth management goals that have been (officially and unofficially) espoused by planning authorities in the region, and to measure these against actual trends. The results are mixed: on the one hand, some key growth management goals adopted by the region are not ambitious compared with existing trends and even these goals are not being met. For instance, the supposedly compact scenario adopted by the region deviates hardly at all from existing growth trends, which regional planners had clearly identified as untenable and requiring drastic change. On the other hand, the region's goal of preserving extensive green areas has been achieved without being watered down during goal formulation or implementation. Whereas these findings may appear contradictory, they are not: conservation in the region has not compromised the potential for growth in the region--at least for the time being. The real test of regional growth management efforts will come in the near future when further expansion meets the 'green wall' on the periphery and NIMBY resistance against densification within existing urban areas. The study suggests that the current structure of regional planning, relying on a partnership between municipal and regional governments, has served the region fairly well in building support for the need for growth management and in elaborating growth management vision. However, there is serious doubt about the ability of this system to set ambitious growth management objectives and to see through the implementation of those objectives in the face of social forces attempting to preserve business-as-usual trends in the region.     

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.     

Growth Management in the Vancouver Region

The Vancouver Region is widely recognised as one North American jurisdiction where strong growth management plans and policies have been put in place in order to control urban sprawl. While many authors have lauded the region for its good planning intentions, there has been little in the way of assessment of actual performance. This paper attempts to identify some quantitative growth management goals that have been (officially and unofficially) espoused by planning authorities in the region, and to measure these against actual trends. The results are mixed: on the one hand, some key growth management goals adopted by the region are not ambitious compared with existing trends and even these goals are not being met. For instance, the supposedly compact scenario adopted by the region deviates hardly at all from existing growth trends, which regional planners had clearly identified as untenable and requiring drastic change. On the other hand, the region's goal of preserving extensive green areas has been achieved without being watered down during goal formulation or implementation. Whereas these findings may appear contradictory, they are not: conservation in the region has not compromised the potential for growth in the region—at least for the time being. The real test of regional growth management efforts will come in the near future when further expansion meets the 'green wall' on the periphery and NIMBY resistance against densification within existing urban areas. The study suggests that the current structure of regional planning, relying on a partnership between municipal and regional governments, has served the region fairly well in building support for the need for growth management and in elaborating growth management vision. However, there is serious doubt about the ability of this system to set ambitious growth management objectives and to see through the implementation of those objectives in the face of social forces attempting to preserve business-as-usual trends in the region.     

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.     

If not here,then perhaps not anywhere: urban growth management as a tool for sustainability planning in British Columbia's capital regional district

In 1995 the provincial government of British Columbia, Canada, passed new legislation encouraging regional districts to prepare Regional Growth Strategies. The strategies were to be means of coordinating municipal action on regional issues. They were also meant to facilitate pursuit of sustainability objectives, including reducing urban sprawl, protecting environmentally sensitive areas, providing affordable housing and decreasing pollution. This paper examines the experience so far in one region that chose to prepare a growth strategy: the Capital Regional District (CRD) at the south end of Vancouver Island. Growth‐management planning in the CRD has been and remains both critical and difficult. The region expects a substantial population increase over the next couple of decades and has a limited land base for urban expansion. Many citizens recognise that their quality of life is high, but vulnerable and, as a result, public support for effective growth management is stronger in the CRD than in many other provincial growth areas. However, BC does not have a tradition of strong regional governance and the CRD as a regional authority is the creature of sixteen municipalities and electoral areas. Seven years into the process, effective growth management still faces substantial challenges, including the persistent jurisdictional protectionism of CRD municipalities. Nevertheless, there have been positive achievements and an admirable diversity of individuals, organisations and initiatives continue to push municipal and regional officials towards a more sustainable future.     

If not here, then perhaps not anywhere: urban growth management as a tool for sustainability planning in British Columbia's capital regional district

In 1995 the provincial government of British Columbia, Canada, passed new legislation encouraging regional districts to prepare Regional Growth Strategies. The strategies were to be means of coordinating municipal action on regional issues. They were also meant to facilitate pursuit of sustainability objectives, including reducing urban sprawl, protecting environmentally sensitive areas, providing affordable housing and decreasing pollution. This paper examines the experience so far in one region that chose to prepare a growth strategy: the Capital Regional District (CRD) at the south end of Vancouver Island. Growth-management planning in the CRD has been and remains both critical and difficult. The region expects a substantial population increase over the next couple of decades and has a limited land base for urban expansion. Many citizens recognise that their quality of life is high, but vulnerable and, as a result, public support for effective growth management is stronger in the CRD than in many other provincial growth areas. However, BC does not have a tradition of strong regional governance and the CRD as a regional authority is the creature of sixteen municipalities and electoral areas. Seven years into the process, effective growth management still faces substantial challenges, including the persistent jurisdictional protectionism of CRD municipalities. Nevertheless, there have been positive achievements and an admirable diversity of individuals, organisations and initiatives continue to push municipal and regional officials towards a more sustainable future.     

Performance and dilemmas of urban containment strategies in the transformation context of Beijing

The implementation of urban containment policies is increasingly attracting attention in environment management. Rapid urban growth and the coexistence of decentralisation and marketisation challenge containment strategies that are implemented to control urban sprawl. This challenge is likely to be greater in a transformation country than in developed countries. This paper evaluates the performance of containment strategies in Beijing. The analysis shows that, to a large extent, containment strategies perform well; however, the decreased compactness of the fringes of the inter-suburban areas, caused by dispersed and illegal development, suggest that municipal containment strategies are being challenged by new trends towards local autonomy. Two similar dilemmas to those faced by developed countries are confronting those involved in the implementation of containment strategies in the current transformation process in Beijing: first, the municipal environmental goal might not be achieved by all local jurisdictions when local economic motivations are involved; and second, macro-scale containment policies are unlikely to control an urban sprawl fuelled by the growing power of market forces.     

Evaluating the Environmental Performance of Urban Parks in Mediterranean Cities: An Example from the Barcelona Metropolitan Region

In a context of increasing urban sprawl and water scarcity common to other Mediterranean cities, this article focuses on the urban parks in the Region of Barcelona (Catalonia, Spain) to examine how these parks are distributed in this region and to assess whether their design and management follow criteria adapted to Mediterranean environmental conditions, especially in what concerns water use. In order to evaluate the environmental performance of these parks, we selected four factors possibly influencing the adoption of park management practices at the local scale: urban density, population size of the municipality, municipal income per capita, and political orientation of the city council. After determining the location and area of urban parks in the region, we correlated these four explanatory factors with several management tasks extracted from two different samples of parks (one of 315 parks and another of 125 parks) and a survey of 86 city councils. Results show that, in general, urban parks were more frequent in large, dense, and left/green municipalities but that environmentally sound practices were more common in small and low-density municipalities. We conclude that changes in certain practices (especially the substitution of high water demanding species) could improve significantly the environmental performance of public spaces in large urban areas with Mediterranean climates. Our observations may be pertinent for other cities interested in the provision of environmental public goods such as parks that necessitate water for irrigation.     

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。     

Barcelona and the delta: metropolitan infrastructure planning and socio‐ecological projects

The delta of the Llobregat river is a natural expansion area for the city of Barcelona. It has been used first for agricultural purposes and then in the twentieth century for urban and infrastructural development. The history of the delta is examined, in order to trace the changing interactions between economic and political forces and ecological processes. This includes the influence of urban planning from 1930 onwards. The paper describes the effort made by the Spanish government from 1991 to co‐ordinate investment planning in the delta with the Catalan administration and local authorities. One municipality, El Prat, has offered a partial environmentalist challenge to the dominant economic development model of other administrations. It is concluded that it would be valuable to consider this key zone in relation to alternative projects for the socio‐economic and ecological development of Catalonia and Spain as a whole.     

Urban sprawl and air quality in large US cities

This study presents the results of a paper of urban spatial structure and exceedances of the 8-h national ambient air quality standard for ozone in 45 large US metropolitan regions. Through the integration of a published index of sprawl with metropolitan level data on annual ozone exceedances, precursor emissions, and regional climate over a 13-year period, the association between the extent of urban decentralization and the average number of ozone exceedances per year, while controlling for precursor emissions and temperature, is measured. The results of this analysis support the hypothesis that large metropolitan regions ranking highly on a quantitative index of sprawl experience a greater number of ozone exceedances than more spatially compact metropolitan regions. Importantly, this relationship was found to hold when controlling for population size, average ozone season temperatures, and regional emissions of nitrogen oxides and volatile organic compounds, suggesting that urban spatial structure may have effects on ozone formation that are independent of its effects on precursor emissions from transportation, industry, and power generation facilities.     

Resident Involvement in Natural Resource Management: open space conservation design in practice

The open space conservation sub-division offers an alternative to large-lot residential sub-divisions often seen as the culprit when urban sprawl transforms rural landscapes. Homes are sited on somewhat smaller lots, preserving natural areas for the local residents who share ownership of these communal areas and assume responsibility for their management. The article focuses on the experiences of residents of 13 relatively new open space communities. The interviews revealed that most of the communities have already confronted conflicting values with respect to natural areas, low resident participation and challenges in accessing appropriate information. While the open space conservation design holds great promise as a tool for innovative approaches to managing residential growth, it also calls for ways to anticipate and assist communities in caring for their local environment. Recommendations are offered for planning professionals based upon the experience of these open space community residents.     

Resident Involvement in Natural Resource Management: Open space conservation design in practice

The open space conservation sub-division offers an alternative to large-lot residential sub-divisions often seen as the culprit when urban sprawl transforms rural landscapes. Homes are sited on somewhat smaller lots, preserving natural areas for the local residents who share ownership of these communal areas and assume responsibility for their management. The article focuses on the experiences of residents of 13 relatively new open space communities. The interviews revealed that most of the communities have already confronted conflicting values with respect to natural areas, low resident participation and challenges in accessing appropriate information. While the open space conservation design holds great promise as a tool for innovative approaches to managing residential growth, it also calls for ways to anticipate and assist communities in caring for their local environment. Recommendations are offered for planning professionals based upon the experience of these open space community residents.     

MINIMIZING THE IMPACT OF URBANIZATION ON LONG TERM RUNOFF1

Increasing concern about the problems caused by urban sprawl has encouraged development and implementation of smart growth approaches to land use management. One of the goals of smart growth is water resources protection, in particular minimizing the runoff impact of urbanization. To investigate the magnitude of the potential benefits of land use planning for water resources protection, possible runoff impacts of historical and projected urbanization were estimated for two watersheds in Indiana and Michigan using a long term hydrological impact analysis model. An optimization component allowed selection of land use change placements that minimize runoff increase. Optimizing land use change placement would have reduced runoff increase by as much as 4.9 percent from 1973 to 1997 in the Indiana study watershed. For nonsprawl and sprawl scenarios in the Michigan watershed for 1978 to 2040, optimizing land use change placement would have reduced runoff increase by 12.3 percent and 20.5 percent, respectively. The work presented here illustrates both an approach to assessing the magnitude of the impact of smart growth and the significant potential scale of smart growth in moderating runoff changes that result from urbanization. The results of this study have significant implications for urban planning.     

Measuring Patterns of Urban Development: New Intelligence for the War on Sprawl

In this article, we compute a variety of measures of urban form (or sprawl) for neighbourhoods of varying age in five study areas in the US to illustrate urban development patterns. Our analysis suggests that some characteristics of development patterns differ significantly within and across study areas and over time; this raises doubt about the utility of sprawl indexes for entire metropolitan areas. The findings suggest, for advocates of 'smart growth', that the good news is that single family lot sizes are falling, density is getting higher and neighbourhoods are becoming more internally accessible. For the same advocates, the bad news, however, is more extensive: houses are becoming larger, neighbourhoods are becoming more isolated, land uses remain separated and pedestrian accessibility to commercial uses is falling. If these trends continue, it is likely that housing will remain unaffordable, traffic congestion will only get worse and developments will be unsustainable.     

Analysis of Changes in Farm Pond Network Connectivity in the Peri-Urban Landscape of the Taoyuan Area,Taiwan

The farm pond system for irrigation is the most prominent feature in the Taoyuan area, Taiwan, giving the region a unique landscape and hydrological character. Although this area had more than 3,290 ponds in the 1970s, fewer than 1,800 now remain. This study analyzes changes in irrigation farm ponds and the canal network landscape in the Taoyuan area. The spatial and temporal changes to ponds and the canal network on the Taoyuan plain were examined graphically for each spatial unit (2,765 m × 2,525 m) using aerial photographs for 1979 and 2005. Landscape metrics were calculated to analyze landscape change associated with increased urbanization. Landscape indices of connectivity and circuitry were utilized to describe changes in the configuration of ponds and canal networks. The total length of canals and total number of ponds in the study area decreased significantly during 1979-2005. The average values of connectivity indices (γ- and α-index) also decreased during 1979-2005, reflecting degradation of canal networks due to urban sprawl. A multivariate technique was applied to portion the study area into three zones according to changes to land cover, ponds, and canal networks. The effects of urban sprawl on the spatial pattern of ponds and canal networks are discussed.     

Transportation energy in global cities: sustainable transportation comes in from the cold?

The energy, environmental and social benefits of sustainable transportation, i.e. public transit, biking and walking, have long been recognized but are now mainstream in global and local transportation policy debates. However, the economic value of sustainable transportation has always been seen as secondary, unless many external costs were included. The results of a new global study show that cities with significant sustainable transportation systems have reduced costs on road construction and maintenance; better operating cost recovery and fuel-efficiency; fewer road accidents and less air pollution. In overall terms, the percentage of city funds going to transportation is reduced. The data show that cities with the most roads have the highest transportation costs and the most rail-oriented cities have the lowest. Further, the most sprawling cities have the highest direct and indirect costs for transportation. Thus, strategies to contain sprawl, to reurbanize, to build new rail systems into car-dependent suburbs with focussed sub-centers, and to facilitate biking and walking, not only will improve energy efficiency but will reduce costs to the economy of a city. Strategies that build freeways and add to sprawl will do the opposite. Trends indicate that moves toward sustainable urban patterns are beginning. The need to operationalize sustainable transportation strategies in planning and engineering practice and in the politics of infrastructure funding remains a major challenge. Some cities are showing how this can be done.