A forecast analysis on world population and urbanization process

The continuous growth of world population and the intensification of urbanization process create a challenge to environment quality and sustainable development around the world. In this paper I tried to conduct a forecast analysis of near-future urbanization related population growth worldwide, based on recent demographic trends. Such an analysis can provide important insights into the prospects for changes in the size and composition of world population and in urbanization process. Optimal polynomial functions were used to fit historical trajectories of population dynamics, and the detailed forecasts of the population mainly over the period 2010–2030 were conducted and analyzed. If the past pattern continues, world total population would increase to 7.94–8.33 billion in 2030 and the annual growth is expected to continually decline in the forecast period. Global total population would stop increasing during the period 2050–2060 and would not exceed 9.5 billion in the future. The total population of Africa, Asia, Oceania, South America, North & Central America would separately increase to 1.35–1.41, 4.86–5.65, 0.04–0.05, 0.44–0.45, and 0.71–0.72 billion in 2030. Europe’s total population is forecast to decline to 0.64–0.67 billion in 2030. World’s rural population is expected to grow to the maximum during the period 2015–2020 and would greatly decline after that period. Global rural population would reach 3.12–3.41 billion in 2030. Rural population in Asia and Africa is estimated to increase and achieve the maximum around 2025 and decline thereafter. For other regions, the rural population would continually decline in the forecast period. Urban population in the world would continually grow and reach 4.72–5.00 billion in 2030, an increase of 48.6–57.8%. However the annual growth of urban population is expected to increase to the maximum (6.86 million/year) during the period 2020–2025 and then decline in the following years. Urban population is projected to continually grow in all regions excepting Europe. Europe’s urban population is expected to decline in the period 2010–2030. Urbanization process worldwide, represented by the ratio urban population versus total population (RUT) and the ratio rural population versus urban population, is expected to continue during the period 2010–2030. The RUT of the world is projected to reach 0.5 before 2010 and would continue to increase in the forecast period. Global RUT is estimated to reach 0.56 in 2030. However, the regional patterns of urbanization process would be diverse. Europe’s RUT is estimated to continually decline in the forecast period and reach 0.68 in 2030. The RUT for Africa and Caribbean would continually increase before 2030, while the RUTs for Asia and South America are estimated to achieve their maximums around 2025 and decline in the following years. Oceania and North & Central America would thoroughly realize urbanization (≈1) during the periods 2020–2025 and 2025–2030. The expansion of world population and urbanization will continually exert a stronger stress to environment quality and sustainable development in a near future. However we may expect this situation would start to change from mid-21st century after total population has achieved its maximum. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.     

城市边界土地增值收益之经济学分析——兼论土地征收中的农民利益保护

经济发展使得城市增长具有必然性。而城市增长又会带来城市内外特定区位土地价格的增加。城市边界区土地价格具有自身的特点。从动态的城市地价模型分析来看．其增值不仅来自于外部性作用，还得益于城市的扩张。城市的扩张有两种方式：一是由于城市化和收入的增加导致城市地租曲线整体向外平移；二是即使人口保持不变，但由于交通的改善使得城市地租曲线逆时针旋转。不能以农业地价来定量边界区土地价格。因为该区土地增值不仅仅来自于外部性，农民具有参与增值分割的权利。应该重新建立土地征收补偿的价格体系．保护农民的合法权利。     

OFF-LINE STORMWATER DETENTION SYSTEMS1

ABSTRACT: This paper looks at the use of off-line detention systems as a means of stormwater management. Conventional detention basins are typically designed and built as in-line systems in which all runoff is directed to the basin. Off-line systems are designed so that only a portion of the runoff is directed to the basin. Several simulation experiments were run to examine the behavior of in-line and off-line systems designed to reduce the peak flow from a developed area to the pre-development level. The results demonstrate that off-line systems require considerably less storage than in-line systems to achieve the same management goal. The results also show that off-line and in-line systems have significantly different flow-duration characteristics with the off-line system generally producing lower flows over longer periods. Unfortunately, off-line systems may exacerbate downstream flooding problems, especially when used in the upper portions of a watershed. Nevertheless, an off-line system can be an alternative to in-line detention in many cases.     

洞庭湖区城镇体系建设研究

洞庭湖区是国内重要的商品粮猪基地。从城市地理学和区域地理学的角度探讨洞庭湖区城镇体系的建设问题,就湖区城镇的规模体系,职能体系和空间体系３个方面展开了专门分析。在城镇等级体系建设方面,应着重加强其中心化趋势和有序性。强调中心城市对于中小城镇的带动作用,科学地确定在不同阶段较大城市的发展规模,形成大中小相结合,结构合理的城镇等级系统。在城市职能体系建设方面,应扬长避短,突出特色,强调产业结构的趋异和     

长江流域城市生态环境问题与跨世纪持续发展战略

综合分析评价了长江流域城市的生态环境态势与问题,城市水环境依然恶化,特别是城市内河道,湖泊水质多污染严重。城市大气污染仍是加重趋向,一些特大城市汽车尾气污染上升,城市酸雨依然严重。城市生态问题沉重,绿地不足,热岛加重,地面沉降,水土流失等。沉重的生态环境赤字已深刻影响到城市经济社会的发展。面对二十一世纪,论证了长江流域城市发展战略,走城市可持续发展之路是唯一战略选择,而建设现代化的山水园林生态城市     

Urban contractual agreements as an adaptive governance strategy: under what conditions do they work in multi-level cooperation?

ABSTRACT

The Norwegian urban growth agreement (UGA) is a governance platform combining transport-infrastructure development with land-use and transport policy. It is a policy package of measures involving network cooperation between national, regional and local government levels established to coordinate transport and land-use development. Shared responsibility for goal achievement, autonomy and learning and adaptation as new knowledge and experience arise are clear prerequisites for the UGAs. This makes it relevant to investigate the conditions for the UGAs to work as an adaptive governance strategy because their central features are in line with the attributes of adaptive governance. Further, adaptive governance is an approach to handle complex problems like transport development issues. The study shows that UGAs have several strengths in terms of autonomy and learning. However, the multi-level cooperation in the UGAs is framed by complex underlying structures of roles and powers, which challenge the working and legitimacy of the governance structures. Multi-level adaptive governance processes like the UGAs require attention to issues of power and legitimacy. Securing transparency and democratic anchorage is paramount in bringing such processes in line with the intended benefits of adaptive governance.     

三峡库区中小城镇城市降雨径流污染特征及现状研究

本研究采用从微观到宏观，在库区沿岸城镇诸多相关因素相似前提下，选择涪陵市为典型试验区；从水文因素，街道地表物累积冲刷规律研究着手，建立累积、冲刷计算模式，计算出涪陵市年降雨径流污染负荷和库区污染荷载因子，同时选择具有代表性的集水闭合小区进行水质、水量同步观测试验进行验证；确定外推因子，计算三峡库区城市降雨径流年冲刷入长江的总固体，ＳＳ，ＢＯＤ５，ＣＯＤ，Ｔ－Ｎ，Ｔ－Ｐ３量分别为５３９６８吨，３８０     

江苏省城乡结合部土地资源利用状况与对策

城乡结合部是城市向农村的过渡带。由于其独特的经济地理位置,使这一地带的土地资源呈现出协同效应活跃、恢复原状机会少、抗干扰能力低、边界变化速度快等生态脆弱性特征。由于人们长期不合理的开发活动,导致了结合部内土地资源数量锐减、质量下降、污染严重、投入减少、地面沉降等生态环境变异。迫使我们采取切实有效的措施,解决日趋严重的城乡结合部土地资源危机。     

A MODELING APPROACH FOR STORM WATER QUANTITY AND QUALITY CONTROL VIA DETENTION BASINS1

ABSTRACT: Storm water detention basins have historically been employed for quantity (i.e., flooding) control only. However, recently it has been suggested that these basins may also provide a practical means of storm water quality control. This paper presents the formulation of a mathematical modeling approach which may be used by professionals to simultaneously design detention basins for the dual purpose of storm water quantity and quality control. Model simulations demonstrate that for a given basin, pollutant removal increases as storm frequency increases. The importance of particle size distribution and settling velocity for net pollutant removal is illustrated, The design procedure is demonstrated, and pollutant loading diagrams for estimating pollutant removal as a function of storm size are developed.     

AN OVERVIEW OF POROUS PAVEMENT RESEARCH1

ABSTRACT: This paper discusses the economics, advantages, potential applications, and status and future research needs of porous pavements. Porous pavements are an available storm water management technique which can be used on parking lots and low volume roadways in order to reduce both storm water runoff volume and pollution. In addition, ground water recharge is enhanced. Also, cost reductions result due to elimination of curbs, drains, and small sized storm sewers. Porous asphalt pavements consist of a relatively thin course of open graded asphalt mix over a deep base of large size crushed stones. Water can be stored in the crushed stone base until it can percolate into the subbase or drain laterally. Other porous pavement types include concrete lattice blocks and a porous concrete mix.