Quantifying the impact of urban area expansion on groundwater recharge and surface runoff

ABSTRACT

In this surface water modelling study, a new spatial evaluation for assessing the impact of urbanization was applied for the semi-arid watersheds intersecting with the Gaza coastal aquifer. The SWAT model was calibrated and validated in a semi-automated approach for streamflow in the main watersheds. The results show that the model could simulate water budget components adequately within the complex semi-arid watersheds. Linear relationships between the change in urban area and the corresponding change in surface runoff or percolation were concluded for the urbanized sub-basins. The urban-surface runoff index (USI) and the urban-percolation index (UPI) were developed to represent a micro-level evaluation of different urban change scenarios in the sub-basins. The global urban-surface runoff index (GUSI) and the global urban-percolation index (GUPI) were derived as macro-level factors reflecting the influence on the overall Gaza coastal aquifer due to urban area expansion.

Editor D. Koutsoyiannis Associate editor E. Rozos     

Statistical interpretation of the daily variation of urban water consumption in Beijing,China

Abstract

The efficient planning and design of water networks, as well as the management and strategies of existing water supply systems, require accurate short-term water demand forecasts. In this study, a statistical model for the estimation of daily urban water consumption was developed. The model was applied to analyse and forecast the daily water consumption in the main district of Beijing, China, from 2006 to 2010. The model exhibited good performance with a coefficient of determination, R², greater than 0.9 in both the calibration and validation periods. The results indicate that: (a) the 7-day moving average temperature is an efficient variable that can be used to depict water-use variation in a year; (b) a daily maximum temperature of 31.1°C and the occurrence of precipitation are two thresholds of water-use behaviour; and (c) the current day’s water consumption has a strong correlation with the consumption of one, two and seven days ago.

Editor Z.W. Kundzewicz; Associate editor D. Yang

Citation Zhang, D.W., et al., 2013. Statistical interpretation of the daily variation of urban water consumption in Beijing, China. Hydrological Sciences Journal, 59 (1), 181–192.     

Social Mix and the Problematisation of Social Housing

Social housing in Australia is at a significant juncture. High levels of housing stress, increasing levels of socio-spatial polarisation and reduced government funding are posing complex policy challenges. Social mix policies are one response to these challenges, arising from the problematisation of social housing estates as socially excluded. This problematisation is examined through case studies of two Sydney social housing renewal projects: Telopea and Riverwood North. Drawing on interviews with government, private-sector and not-for-profit housing practitioners, the paper identifies two distinct discourses of social exclusion within this problematisation—culture of poverty discourse and equity discourse—that shape the implementation of social mix. These discourses reveal that implementing social mix is more complex than simply managing the cohabitation of residents in different tenures. Rather, the practice of social mix is embedded within discourses about the nature and causes of social exclusion. These discourses, in their turn, inform the multiple and sometimes conflicting aspirations pursued through social mix policies.     

Voronoi图和实景影像在城市POI选址中的应用

以北京西城区为例,通过Voronoi图将兴趣点划分成多个区域;在部件集中且兴趣点少的区域,通过建立基于Voronoi分区的minisum选址模型,得到理论上的新增兴趣点的坐标;然后通过移动道路测量车采集实景影像定位到理论的兴趣点点位上;并在其附近一定范围内寻找最近的有标志意义的地物作为实际位置的兴趣点,达到对兴趣点快速更新的目的,极大提高了城市管理者在日常工作和应对突发事件时的实时性和高效性。     

区域规划空间信息系统建设与应用研究——以江苏省城乡规划信息系统为例

区域性城乡规划信息系统建设开展较晚,与城市级规划信息系统不同,其应用需求、数据构成、技术架构具有其独特性。结合新一轮江苏省城镇体系规划修编工作,开展全省城乡规划信息数据建库和应用平台的开发工作,系统根据区域规划的编制和研究应用需求,制定了面向未来区域规划工作需求的数据标准,集成了全省多源、多尺度、多时态的空间数据,实现了跨专业、跨平台空间信息的整合与共享。为江苏省城镇体系规划以及其他相关编制提供数据分析、规划决策支撑等服务,并预留未来与其他各类地理信息系统的应用接口。     

Monitoring the built-up environment of Shanghai on the street-block level using SAR and volunteered geographic information

ABSTRACT

In this geo-statistical analysis of change detection, we illustrate the evolution of the built-up environment in Shanghai at the street-block level. Based on two TerraSAR-X image stacks with 36 and 15 images, covering the city centre of Shanghai for the time period from 2008 to 2015, a set of coherence images was created using a small baseline approach. The road network from Open Street Map, a volunteered geographic information product, serves as the input dataset to create street-blocks. A street-block is surrounded by roads and resembles a ground parcel, a real estate property – a cadastral unit. The coherence information is aggregated to these street-blocks for each observation and the variation is analysed over time. An analysis of spatial autocorrelation reveals clusters of similar behaviours. The result is a detailed map of Shanghai highlighting areas of change. We argue that the aggregation and grouping of synthetic aperture radar coherence image information to real-world entities (street-blocks) is comprehensible and relevant to the urban planning process. Therefore, this research is a contribution to the community of urban planners, designers, and government agencies who want to monitor the development of the urban landscape.     

Web-based visualization of large 3D urban building models

Adaptive rendering of large urban building models has become an important research issue in three-dimensional (3D) geographic information system (GIS) applications. This study explores a way for rendering web-based 3D urban building models. A client–server hybrid rendering approach is presented for large 3D city models, stored on a remote server through a network. The approach combines an efficient multi-hierarchical building representation with a novel image-based method, 3D image impostor generated on demand by a remote server. This approach allows transferring complex scenes progressively while keeping high visualization quality. We also evaluated the rendering and data transferring performance of the proposed approach.     

Compact,concurrent, and contiguous: smart growth and 50 years of residential planning in the Toronto region

In this article, we use parcel-based land-use data to analyze 50 years of residential development in the Toronto region. We test two hypotheses: (1) Toronto’s form does not conform to conventional definitions of suburban sprawl and (2) Toronto’s suburban development shows high levels of continuity over time with relatively high densities and mixed housing types. Contrary to recent research suggesting a convergence of urban forms among North American metropolitan regions, Ontario’s robust planning system has created a distinctive, highly consistent pattern of residential development that has, for half a century, achieved many of the core goals of smart growth including relatively compact, contiguous, and concurrent development. This form continues to be automobile dependent, however, and is not producing many of the benefits ascribed to smart growth. Rather than continuing to adopt United States-inspired smart growth policies, a more ambitious set of initiatives will be required to address current regional challenges.     

“Building glass refrigerators in the desert”: discourses of urban sustainability and nation building in Qatar

Planners around the Arab Gulf states are increasingly drawing on narratives about “urban sustainability,” despite the fact that the explosive growth of urban centers in the Arabian desert largely defies the logic of sustainability. In this article, I consider how and with what effect these narratives have been deployed by various actors in Doha, Qatar. Eschewing a simple economistic reading, I highlight political geographic context and analyze how actors mobilize and rework these discourses. Drawing on mixed-methods fieldwork in Fall 2013, I illustrate how sustainability narratives are mobilized together with nationalist tropes about modernizing Qatar and building up the country’s international prestige, while preserving local traditions and culture through the built environment. With a focus on recent efforts to green Doha, this analysis sheds light on the disciplining function of nationalist discourses in the production and constitution of what it means to label development practices “green” in contemporary Qatar.     

Planning for growth in a natural resource boomtown: challenges for urban planners in Fort McMurray,Alberta

Between 2000 and 2010, the population of the city of Fort McMurray, Alberta increased by 80%, mainly due to the expansion of oil extraction projects and subsidiary industries. Population growth of this magnitude has significant consequences for city planning. While Fort McMurray struggles to keep up with enormous numbers of in-migrants, the cost of living in the city has skyrocketed. Using interviews with city planners and field experience in the city, in this paper I examine the current challenges faced by urban planners in Fort McMurray against the backdrop of global economic decision-making, corporate influence, and commodity dynamics. While the recession of 2008 gave city planners some breathing room, they still struggle with gathering accurate census information and predicting population growth, providing affordable housing, and balancing short-range planning with their long-term goals. Attempts by city planners to address these challenges could provide a contemporary model for urban planning in rapidly growing, resource-dependent communities.