城市化对地下水流系统的影响

随着世界经济的飞速发展和人口增长,城市的规模和数量也在急剧增加,城市化的趋势变得日益明显,尤其在发展中国家。在这一过程中,地下水所扮演的角色越来越重要,揭示城市化与地下水各方面之间的相互影响规律以实现其可持续发展,成为一个全球性的重要研究课题。本文在分析世界城市人口增长规律和地下水对城市供水的重要性基础上;以三个典型示范城市为例,进一步具体探讨了城市化对地下水补给与地下水流系统的影响。最后认为,城市化会引起地下水补给量的增加;但城市大规模和经常性毫无节制地开采地下水可产生明显的地下水位下降、地面沉降和盐水入侵而导致地下水流系统的剧烈改变。     

Global extent and distribution of artificial, residential waterways in estuaries

Artificial residential waterways are now widespread in the world’s estuaries. We used the global mapping tool, Google Earth, to determine that there are nearly 4000 linear km of artificial waterways globally, covering an area of 270 km². Residential waterways constructed as open, flow-through canal estates are at their greatest extent in North America (77% of global linear extent), where systems are typically longer and narrower, with more openings and dead-ends than systems elsewhere. The remaining canal estates are spread across all other continents except Antarctica: Asia (7%), Europe (7%), Oceania (7%), South America (0.9%), and Africa (0.6%). A relatively recent design change from open canals to artificial estuarine lakes with tidal barriers has occurred on all continents except Africa, most extensively in Australia (14 km² area, 57 independent systems). The extremely large expansion in artificial residential waterways aimed at increasing opportunities for waterfront living by humans has also modified and expanded estuarine habitat available to aquatic biota. Research can best underpin planning and management of these types of waterways by focussing on their value as habitat and their provision of other goods and services.     

BOOK REVIEWS

Book Reviewed in this article: Unfairly Structured Cities . Blair Badcock Religion and Rural Revolt . Janos M. Bak and Gerhard Benecke The Industrial Geography of Canada . Anthony Blackbourn and Robert G. Putnam The Cuban-American Experience, Culture, Images, and Perspectives. Thomas D. Boswell and James R. Curtis Quaternary Paleoclimatology . R. S. Bradley Development and Crisis in Brazil, 1930–1983 . Luiz Bresser Pereiras Centres of Origin in Biogeography . John C. Briggs Analytical Urban Geography . Martin Cadwallader Geomorphology . Richard J. Chorley , Stanley A. Schumm, and David E. Sugden South Africa: The Impact of Past Geographies . A. J. Christopher The Geography of Underdevelopment. A Critical Survey . D. K. Forbes Health Care in Developing Countries . Wilbert M. Gesler Place to Grow Old: The Meaning of Environment in Old Age . Stephen M. Golant The Emerging Marine Economy of the Pacific . Chennat Gopalakrishnan An Introduction to Agricultural Geography . David B. Grigg The Soviet Union: A Geographical Study . G. Melvyn Howe Geographical Aspects of Health: Essays in Honour of Andrew Learmonth . N. D. Mc Glashan and J. R. Blunden Physical Geography: A Landscape Appreciation . Tom L. Mc Knight Mountain Experience. The Psychology and Sociology of Adventure. Richard G. Mitchell Jr . Systematic and Regional Biogeography. Stanley A. Morain The Economic Transformation of American Cities. T. J. Noyelle and T. M. Stanback , Jr . Normal Accidents: Living With High-Risk Technologies. Charles Perrow Vanishing Farmland: A Legal Solution for the States. Sarah E. Redfield Applied Methods of Regional Analysis: The Spatial Dimensions of Development Policy. Dennis A. Rondinelli Urbanization in Romania. A Geography of Social and Economic Change Since Independence. Per Ronnas Statistical Techniques in Geographical Analysis. Gareth Shaw and Dennis Wheeler The Granite Garden: Urban Nature and Human Design. Anne Whiston Spirn Political Geography: Recent Advances and Future Directions. Peter Taylor and John House Geographia y Medio Ambiente. Manuel Valenzuela -Rubío Nãgara and Commandery: Origins of the Southeast Asian Urban Traditions. Paul Wheatley The Common Fisheries Policy of the European Community. Mark Wise Geography and Gender. Women and Geography Study Group of the IBG Technological Hazards. D. J. Zeigler , J. H. Johnson , S. D. Brunn     

Are all cities with similar urban form or not? Redefining cities with ubiquitous points of interest and evaluating them with indicators at city and block levels in China

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.     

发达国家城镇化形式的演变及其对中国的启示

对发达国家城镇化阶段性特征及发展趋势的全面分析发现,城镇化的本质在于社会整体生活质量的提高和区域可持续发展。发达国家城镇化从中心集中型城市化、郊区城市化、去城市化到再城镇化的进程及其伴生的社会和环境问题,是由于政府职能的缺位和过分依赖市场的力量所致,是一种历史的偶然或错误而非客观规律。城市区域作为一种新的城镇化模式在提高区域可持续发展方面的优势正在被发达国家近年来的实践所证明。在经济增长方式、社会以及环境条件均已发生了显著变化的前提下,中国的城镇化应当在全面研究和充分汲取发达国家城镇化过程中的经验和教训的基础上,通过积极主动和科学合理的政策干预城市区域的发展。     

Regional development and the impact of the public sector in Denmark: employment growth and human capital

This paper analyses the relationships between employment growth, human capital and regional development. To understand the spatial development of employment growth, we distinguish between the public and the private sector. The public sector has a major role in Denmark in the form of a large share of total employment and employment growth across space. We examine in particular the uneven geography of human capital and the relationships between the growth of human capital and total employment growth by Danish municipalities. It is moreover analysed, whether there is a concentration of human capital in the largest city-regions, and how such concentrations contribute to the uneven geography of employment growth. The paper concludes that both the public and private sectors are important regarding employment growth in Danish municipalities. Further, public and private human capital contributes to employment growth, and the public sector contributes, over time, to diminishing the uneven spatial distribution of human capital while the private sector increases the spatial inequality. Moreover, urbanisation has a significant effect on employment growth and human capital formation, both when it comes to the large city regions, and, in general, the distance to city centres.     

Economic reforms and the New Master Plan of Ho Chi Minh City, Vietnam: Implementation issues and policy recommendations

The economic reforms or `doi moi' introduced in 1986 have transformed Vietnam's planned economy to a more market-oriented one. Rise in international capital, market liberalisation and greater population mobility have contributed towards a greater concentration of squatters in the city centre, and extended metropolitan development in the fringes of Ho Chi Minh City. Rapid urbanisation and, to a lesser extent, industrialisation have converted large tracts of farmlands to urban use, and greater rural exodus. Such dramatic changes have drawn the city government's attention to face the new challenges. As a very important political and economic centre in the south, Ho Chi Minh City has prepared for itself a new Master Plan, approved in 1997, to provide a legitimate and institutional framework to guide its future spatial development. This paper introduces the background and explains the rationale behind the drafting of the Master Plan, and highlights the constraints that are expected in implementing it. The administrative framework in planning is also examined in terms of its advantages and disadvantages in a planning system with four levels: national, provincial, district and local. Land availability in the city centre, source of funding and technical expertise are all parts and parcels of the challenges in the process of modernising HCMC to accommodate the need of its residents and rapid global change. Ho Chi Minh City's strong relationships with its hinterlands have equally required the planners to look at the planning field using the whole national and regional scenarios. Policy recommendations aimed at improving the implementation capability are finally presented. This revised version was published online in July 2006 with corrections to the Cover Date.     

Russian cities at a crossroads

The research project `Changes in the Russian urban system after the dissolution of the Soviet Union' supported by the German Science and Research Society aims to reveal the impact of change in (1) the national and regional urban network, (2) the type and condition of Russian cities, and (3) the factors and actors affecting urban development. In this contribution the focus is made on the first task. The authors argue that visible stabilisation of the Russian urbanisation under crisis and/or under a new stage involves a good deal of restructuring and qualitative change. The hierarchy of the nation-wide functional centres is in flux. Within regions `alternative' foci attract industries, capital and people, and compete with regional capitals. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rural diversification and socio-economic transformation in Croatia

Rural diversification in Croatia is well advanced because many rural families have been able to find work in secondary and tertiary activities without the need to migrate to the towns. Many rural settlements have now attained an urban character although there are regional variations, including a contrast between the continental zone with a relatively high level of commitment to agriculture and the coastal areas, with pronounced ‘deagrarisation’ where the ports and tourist resorts are well developed and the natural resource conditions for agriculture are poor. These variations are examined at the municipality level with reference to two key indicators: the share of nonagricultural population and the share of workers in the total active population. Four categories of socio-economic transformation are recognised: more urbanised, urbanised, less urbanised and rural. The main regional differences between the continental and coastal areas are confirmed with the latter showing a relatively high level of socio-economic transformation through the prominence of more highly urbanised municipalities. This revised version was published online in July 2006 with corrections to the Cover Date.