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1.
This paper assesses the various factors contributing to climate change in the region of the Kashafroud G-WADI Basin in Iran; quantifies the local impacts of climate change, especially local water scarcity; and simulates and discusses several proposed methods to combat these impacts. Hydrologic and climatic data are statistically analyzed and VENSIM modeling is used for various simulations of water resources in the basin. Results show that the natural climate changes affecting Kashafroud Basin include increased temperature, less rainfall, more frequent droughts, and changes in rainfall patterns, all of which are local symptoms of climate change in recent years. However, the most important challenge in the basin is the overexploitation of surface and groundwater resources to meet the growing water demands, especially domestic needs. Changes in land use, reallocation of water uses, groundwater depletion, and degradation of the quality of surface waters have all contributed to significant changes in the environmental features of this basin, and are the main reason why water demands now exceed the renewal capacity of the basin. Proposed response measures include reallocation of resources among different uses, inter-basin water transfers, drawing water from six small dams on the Kashafroud River, reducing groundwater extraction, and replacing groundwater extraction for agriculture by reuse of urban wastewater. This study concludes that although changes in global climatic parameters have altered environmental features in the basin, local factors, such as water utilization beyond the renewable capacity of the basin, are more significant in worsening the impacts of climate change.  相似文献   

2.
This paper examines the interrelationship between urbanization and water supply privatization in cities in the global South. The purpose of the paper is not to evaluate the impacts of privatization; rather, the paper analyses the differences in pathways and modes of water supply privatization, focusing on urban and contrasting with rural areas. A distinction is drawn between privatization (organizational change) and commercialization (institutional change) of water supply. Emphasis is placed upon the interrelationship between regulatory change (a shift from public to private management of water supply systems), human use of and access to water, and urban waterscapes. In contrast to metaphors of 'networks' so often applied in analyses of water management, the 'archipelago' is posited as a metaphor which better captures the complex overlapping strategies of water supply provision in urban areas in the South. Building on this metaphor, and in response to the 'public–private' dualism often invoked in studies of privatization, the paper outlines an alternative typology of water management in urban areas in the South. This typology foregrounds the concepts of the territorialization of corporate power as a means of understanding the articulation between privatization and urbanization processes in the South.  相似文献   

3.
In this article, we analyze the production of inequalities within the centralized water supply network of Lilongwe. We use a process-based analysis to understand how urban infrastructure is made to work and explain the disparity in levels of service by tracing the everyday practices of those who operate the infrastructure. This extends existing analyses of everyday practices in relation to urban water inequalities in African cities by focusing on formal operators, rather than water users, and looking within the networked system, rather than outside it. Our findings show that these practices work to exacerbate existing water stress in poor areas of the city. We conclude with a reflection on how understanding these practices as the product of the perceptions, rationalizations, and interpretations of utility staff who seek to manage the city’s (limited) water as best they can offers insight into what is required for a more progressive urban water politics.  相似文献   

4.
中国大城市病典型症状诱发因素的实证分析   总被引：5，自引：0，他引：5  
论文基于已有研究将大城市病细分为交通拥堵、资源短缺、环境污染3种典型症状,采用2013年全国204个地级市横截面数据,根据夜间灯光数据构建人口空间分布指标,首先运用OLS回归探讨城市规模、空间失衡、建设滞后、产业转型、体制弊病等5种主要致病因素对大城市病的影响;其次,建立门槛效应模型进一步考察不同因素与大城市病之间是否存在非线性关系。实证研究结果表明,大城市病作为一种“综合病”,具体到不同层面对应的主要致病因素也大相径庭。其中,城市总体规模较大、城区人口过度集中分布、交通基础设施不够完善等是造成交通拥堵的主要原因;大城市中并不普遍存在资源匮乏的问题,相反地,产业结构的改善、公共服务的增加、行政权力的集中均有助于吸引和调动资源;此外,不论是城区人口总量的增加,还是分布结构的集中化,均显著不利于消除环境污染,并且非农产业比重的上升和城市道路面积的扩张也会对城市生态环境系统造成破坏。  相似文献   

5.
As a multifunctional activity and land use, urban agriculture supports a range of objectives, from urban greening to food security. However, it is often left out of urban policy. As a result of the highly contextual and cross-cutting nature of urban agriculture, there are relatively few comprehensive and formalized regulatory tools to draw from. Different cities around the world are now deciding how to fit urban agriculture into the urban agenda; however, in many places urban agriculture continues to operate in the absence of legitimization due to its relatively mobile and dynamic nature. This article looks at the importance of local and central governments in promoting sustainable urban agriculture. Through participatory action research, it examines the cases of Dar es Salaam, Tanzania and Copenhagen, Denmark to understand stakeholder interactions, as well as present and future barriers to the conservation of existing urban agriculture and future initiatives. The findings suggest that municipal recognition and institutional support for urban agriculture is an important component in increasing the sustainability of related initiatives. Local and central government plays a role in the legitimization and institutionalization of urban agriculture through the facilitation of multi-stakeholder processes, policy development and the conservation and allocation of land.  相似文献   

6.
The peri-urban area is the region where there is a more dynamic interaction between the urban and rural. The peri-urban area supplies natural resources, such as land for urban expansion and agricultural products to feed the urban population. In arid and semi-arid lands, such as northern Mexico, these areas may also be the source of water for the city's domestic demand. In addition, scholars argue that peri-urban residents may have a more advantageous geographical position for selling their labour and agricultural products in cities and, by doing so, sustaining their livelihoods. A considerable number of studies have examined the peri-urban to urban natural resources transfer in terms of land annexation, housing construction, and infrastructure issues; however, the study of the effects of the reallocation of peri-urban water resources to serve urban needs is critical as well because the livelihoods of peri-urban residents, such as those based on agriculture and livestock, depend on water availability. In the case of Hermosillo there is a tremendous pressure on the water resources of peri-urban small farm communities or ejidos because of urban demand. Based on interviews and structured surveys with producers and water managers, this paper examines how peri-urban livelihoods have been reshaped by the reallocation of the city's natural resources in many cases caused some ejido members or ejidatarios to lose livelihoods.  相似文献   

7.
辽中地区矿业城市水资源供需平衡动态分析   总被引：4，自引：0，他引：4  
顾康康  刘景双  陈昕 《地理学报》2008,63(5):473-481
辽中地区矿业城市是我国重要的能源生产和重工业基地,研究其水资源供需变化有利于实现水资源可持续化管理,促进经济、生态协调发展。分析了水资源供需平衡框架,可利用水资源和需水量的计算方法,以及水资源供需平衡的影响因子。结果表明:1997-2005年,辽中地区矿业城市水资源供需区域差异明显,鞍山市水资源供需失衡明显,但缺水量逐渐降低,2005年仅缺水0.32×108m3,水资源开发利用率平均达到65.56%,用水属于高度紧张;抚顺市水资源供需基本持平,近几年余水量逐渐增大,2005年余水5.25×108m3,水资源开发利用率平均达到35.11%,用水属于中高度紧张;本溪市水资源供需平衡,可利用水资源大于需水量,2005年余水8.65×108m3,水资源开发利用率平均达到27.96%,用水属于中高度紧张。鞍山的需水结构以农业需水和生态环境需水为主,两者达到总需水量的76%;抚顺以生态环境需水为主,达到60%,农业需水次之,达到23%;本溪生态环境需水达到67%,工业需水次之,为15%。自然条件的差异是水资源供需变化差异的基础,人类社会经济活动和政策法规是水资源供需变化的主要影响因子。  相似文献   

8.
Most scholarship on rural–urban migration in Sub-Saharan Africa demonstrates that migrants tend to move in a “circular” fashion and only spend short periods of time in cities before returning home to rural villages. However, some scholars working on the impacts of climate change on migration suggest that deteriorating environmental conditions may undermine rural livelihoods and lead people to move to cities for longer periods of time. If this is true, then climate change threatens to accelerate urbanisation and lead to renewed stress on urban infrastructure. The purpose of this paper is to explore these positions and we do so by collecting survey [n = 241], in-depth interview [n = 75] and focus group [n = 123 participants] data from rural and urban Malawi. Two key results stand out as significant. The first is that migrants in Malawi's capital city tend to stay in the urban environment for longer periods of time than conventional understandings of migration would predict. The second key result is that climate change may actually lead, in the case of Malawi, to reverse (i.e urban–rural) migration. This is because many of the people in Malawi's cities depend on products produced in rural environments (e.g. food and fuelwood). If climate change undermines rural livelihoods, then many urban residents will find the basis of their livelihoods removed and will likely respond by moving back to rural villages. Overall, our results, therefore, suggest that in at least one case the effect of climate change on migration may not be to increase migration towards cities but to stimulate an exodus from cities and back to the rural countryside.  相似文献   

9.
Oases in arid northwestern China play a significant role in the region's economic stability and development. Overexploitation of the region's water resources has led to serious environmental consequences. In oases, irrigated agriculture is the primary consumer of water, but water shortages resulting from dramatically growing human needs have become a bottleneck for regional sustainable development, making effective management of the limited available water critical. Effective strategies must be formulated to increase agricultural productivity while reducing its environmental impacts. To support the development of such strategies, water use patterns were analyzed during the 2007 and 2008 growing seasons, from May to early October, to identify opportunities for improving water management using the Molden-Sakthivadivel water-accounting method, which combines groundwater and surface water into a single domain and can provide a good estimate of the uses, depletion, and productivity of water in a water basin context. The study area lies in Linze County, Gansu Province, China. In the study area, the inflow water resources consist of irrigation, precipitation, and soil water, which accounted for 89.3%, 8.9%, and 1.8% of the total in 2007, and 89.3%, 4.8%, and 5.9% in 2008, respectively. The irrigation depends heavily on groundwater, which accounted for 82.1% and 83.6% of the total irrigation water in 2007 and 2008, respectively. In 2007 and 2008, deep percolation accounted for 50.1% and 47.9% of the water outflow, respectively, with corresponding depleted fractions of 0.51 and 0.55, respectively. For the irrigation district as a whole, the water productivity was only 1.37 CNY/m3. To significantly increase crop water productivity and prevent depletion of the region's groundwater aquifer, it will be necessary to reduce the amount of water used for irrigation. Several water-saving agricultural practices are discussed and recommended.  相似文献   

10.
Urban appropriation is a key dimension of both Lefebvre's widely hailed ‘Right to the City’ and Bayat's concept of ‘quiet encroachment’. For Lefebvre, appropriation is a (generally unrealized) claim by those who do not ‘have’ the city of a right to ‘take’ it. Bayat, in contrast, characterizes actually existing appropriation as motivated by everyday needs, not aimed at wider social change. While both theorizations may be useful, we argue that a third mode of appropriation is apparent in South African urban contexts. Actors often act in ways that could be characterized as appropriative, yet do not work to consolidate an abrogated appropriative right or durable permission. Nor are they adequately explained as apolitical or individualistic; the logic used to justify them similarly is based neither on rights nor needs. We label such appropriation ‘agonistically transgressive’. We argue that agonistically transgressive appropriations are particularly evident in post‐apartheid South Africa, in part because of changing urban conditions and consequent renegotiations of spatial regulation. Using examples of urban land appropriation for housing in South Africa, we briefly illustrate how thinking pluralistically about urban appropriation might help better understand its actually existing forms in—and beyond—the global South.  相似文献   

11.
Urban forms reflect spatial structures of cities, which have been consciously and dramatically changing in China. Fast urbanisation may lead to similar urban forms due to similar habits and strategies of city planning. However, whether urban forms in China are identical or significantly different has not been empirically investigated. In this paper, urban forms are investigated based on two spatial units: city and block. The boundaries of natural cities in terms of the density of human settlements and activities are delineated with the concept of ‘redefined city’ using points of interests (POIs), and blocks are determined by road networks. Urban forms are characterised by city-block two-level spatial morphologies. Further, redefined cities are classified into four hierarchies to examine the effects of different city development stages on urban forms. The spatial morphology is explained by urbanisation variables to understand the effects. Results show that the urban forms are spatially clustered from the perspective of city-block two-level morphologies. Urban forms tend to be similar within the same hierarchies, but significantly varied among different hierarchies, which is closely related to the development stages. Additionally, the spatial dimensional indicators of urbanisation could explain 41% of the spatial morphology of redefined cities.  相似文献   

12.
l introductionYucheng area is located in the downstream alluvial plain of the Yellow hiver in Shandong provillce,Nortll China. bouenced by the conhnenlal monsoon clllnate in wann tCmperate zone, fainfall isdistributed very unevenly in bine. AVerage annual precipitation amounts to 600 ~ with 70%concentrahng from June to September The mother material of soil is conStituted by river alluvium andmainly consistS of mealy sand and light loam. Vadose zone consistS of mealy san4 its dry bulk densi…  相似文献   

13.
基于GIS的西安市雨水收集潜力估算   总被引：1，自引：0，他引：1  
随着城市化进程的加快,城市地表水污染的加重,地下水超量开采引发的一系列问题,城市用水量严重不足,开发利用雨水资源已经成为解决城市缺水问题的一个重要的途径。定量研究城市雨水资源可供收集利用量可为开展城市雨水资源化利用提供理论基础。以西安市绕城高速以内为研究区域,把其汇水面划分为九类,以GIS为工作平台,计算出每种类型汇水面的面积,并确定了各自的径流系数。通过对西安市近45年降雨量的分析,结合降雨总量、理论可收集雨水量和实际可收集雨水量的计算公式,在降水保证率为50%和75%的条件下,估算出西安市绕城高速公路内1年可收集的雨水量分别为1.11×108m3和0.93×108m3,大约相当于西安市2005年用水量11.4×108m3的9.7%和8.1%。  相似文献   

14.
民勤绿洲50余年水利建设的生态经济影响   总被引：3，自引：1，他引：2  
民勤绿洲近50余年地表来水持续减少,为满足用水需求,兴修了一系列水利工程。以民勤县50余年的经济发展和生态环境数据为基础,从农业发展、产业结构调整以及生态环境要素的角度,运用图表对比分析研究区50余年内发生的生态和经济变化,进而研究了水利工程建设在这两方面所产生的影响。结论表明:在2012年来水量比水利工程建设前即1956年减少32.3%的背景下,水利工程建设支撑了民勤绿洲农业的发展;保证了3次产业结构向节水循环型方向调整,第一、二、三产业产值之比从1956年的14.9:3.2:1变成了2012年的1.2:1.1:1。但水利工程建设也对民勤的生态环境产生了负面影响,加剧了该区的地下水位下降及水质恶化、植被退化、土地沙漠化及盐碱化等生态问题。  相似文献   

15.
《Urban geography》2013,34(7):953-972
Although water demand theories identify price structures, technology, and individual behavior as determinants of water demand, limited theoretical or empirical evidence suggests a link between urban development patterns and water use. To assess the role of urban development patterns on water demand, we used GIS and statistical models to analyze single-family residential water consumption in the Portland, Oregon, metropolitan area. Our results show that residential water consumption per household at the census block group scale is best explained by average building size, followed by building density and building age, with low water consumption areas clustering together and typically located in high-density and older neighborhoods. Accounting for spatial dependence among residuals, explanatory variables explain up to 87% of variations in water consumption. Our results help to develop a water demand framework that incorporates existing factors with urban development policies to more effectively manage limited water and land resources.  相似文献   

16.
Hydrological Studies and Water Resource Concerns in Southeast Asia   总被引：1，自引：0，他引：1  
Water supply shortage has become a pressing issue in Southeast Asia in recent years. While on the one hand water demand is escalating with rapid economic development, urbanisation and related population concentrations, on the other, surface water supply sources are increasingly being threatened by the resultant land use changes. Therefore, any understanding of the region's water supply concerns necessarily takes into account the hydrological processes and changes consequent to human interference of the natural environment. Changes to the environment that curtail the quantity of water supply and affect its quality will in turn have implications for water resource issues in megacities and other urban areas. Equally critical to the supply of water are water resource and management issues, in particular, the adequate provision of safe water for human consumption, regarded as not only meeting a basic need but also a human right. This paper provides an overview of hydrological processes and water resource concerns and suggests the scope for further investigation, particularly by geographers.  相似文献   

17.
Agriculture on the fringes of cities across the Global North is increasingly perceived as making an important contribution to urban sustainability. As Australian cities continue to expand and encroach on their peri-urban peripheries, there is rising concern about loss of farmland to housing. Such concerns are especially urgent in the Sydney Basin, due to population growth, and topographical and land-use constraints. Accounting for the Basin's farmlands, however, remains opaque, not unrelated to difficulties in acquiring reliable data on the area and value of Sydney's agricultural industries. The problem is not simply that there are no data available but rather that the nature of existing data is (often hotly) contested. Critical questions for urban planners therefore remain unanswered, including: is peri-urban agriculture as important as advocates suggest? Are metropolitan food supplies under threat? If peri-urban farmland is important, what should be done to preserve it? In collating and analysing existing Australian Bureau of Statistics (ABS) and non-ABS data on Sydney agriculture between 1992 and 2011, we outline the need for more reliable and consistent longitudinal data to enable better planning for Sydney's farmland into the future. Notwithstanding limitations of available data sources, our findings reveal trends in Sydney Basin agriculture that invite debate on many assumptions about the nature of peri-urban agriculture. These findings emphasise the importance of geographically specific, evidence-based analysis as a basis for planning for peri-urban agriculture.  相似文献   

18.
Cities and city regions are on the global agenda as key sites for contemporary societal development, in terms of agglomeration of economic activity, places of everyday life and dense networks. The majority of economic, political and social activities is today formed by urbanisation, and an increasing number of people are living and working in city regions. At the same time, many cities and peripheral regions are struggling with job losses, industrial restructuring and depopulation, and thus, many countries face new forms of spatially economic and social inequalities. This special issue is about the contemporary urbanisation processes and the transformation of cities and urban systems in the European context using Denmark as a particular case. Denmark provides a present-day example of urban transformation, and its urban system resembles that of many other European countries – Denmark having one large urban centre and a long tail of smaller cities and towns. Thus, the papers in this issue provide insights into contemporary urban changes.  相似文献   

19.
In Freetown, the capital city of Sierra Leone, rapid urbanisation combined with the lingering impacts of the devastating decade long civil war (1991–2002), has left large portions of the population without reliable work or income. One response to this has been an increase in urban and peri-urban agriculture (UPA) which provides participants with employment, income and food security. According to local government estimates, women comprise around 80% of Freetown’s UPA community, and many women rely totally on UPA as a livelihood strategy to feed and support their households. This article focuses on the experiences of these women farmers, and in doing so sheds new light on their vital contribution to Freetown’s growing UPA community who are not thus far represented in published literature. Globally, women are also underrepresented in UPA literature, and as a result their distinct challenges are not well understood. Reporting on field-based research, this article identifies challenges facing Freetown’s women farmers, including land tenure, access to clean water, limited capital for purchasing tools, fertilisers, and pesticides, and difficult relationships with government, NGOs, and other farmers. The manner in which these challenges manifest themselves in relation to women farmers, as distinct from their male counterparts, are identified, and opportunities for Freetown’s UPA community to support and empower women farmers will be highlighted.  相似文献   

20.
Abstract

This paper explores the dynamics behind the changing regimes of urban renewal and its social impacts in Taiwan. Before the 1980s, the state was willing to solely shoulder the job of urban renewal with a wholly supportive financial budget and land appropriation law, while in the 1990s it became financially overburdened due to its renewal policy. Around the year 2000, the state turned towards promoting urban regeneration as a key business model. Through this historical exposition, the Taiwanese story of state transformation in urban renewal policy brings two issues to the fore. The first issue is the learning process concerning the policy of public-private partnership (PPP) initiatives. Trans-border policy mobility connects and constitutes cities, such as Taipei, with other places, such as London, through visits and seminars attended by policy makers and experts. However, policy transferred from abroad is “localized” in the learning process and used to prioritize the regeneration of public lands in the urban area. The PPP model is transformed in the face of domestic political struggles. The second issue is the social exclusion as a result of property-led regeneration. Rather than playing the role of an impartial institutional moderator, the state privileged landowners and developers and sacrificed the rights of tenants to stay put. By doing so, the state secures political support from landowner-cum-citizens and initiates a political culture of property in which local citizenship is predicated on ownership.  相似文献   

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