DEVELOPMENT OF WATERSIIED MODELS FOR TWO SIERRA NEVADA BASINS USING A GEOGRAPHIC INFORMATION SYSTEM1

ABSTRACT: Techniques were developed using vector and raster data in a geographic information system (GIS) to define the spatial variability of watershed characteristics in the north-central Sierra Nevada of California and Nevada and to assist in computing model input parameters. The U.S. Geological Survey's Precipitation-Runoff Modeling System, a physically based, distributed-parameter watershed model, simulates runoff for a basin by partitioning a watershed into areas that each have a homogeneous hydrologic response to precipitation or snowmelt. These land units, known as hydrologic-response units (HRU's), are characterized according to physical properties, such as altitude, slope, aspect, land cover, soils, and geology, and climate patterns. Digital data were used to develop a GIS data base and HRIJ classification for the American River and Carson River basins. The following criteria are used in delineating HRU's: (1) Data layers are hydrologically significant and have a resolution appropriate to the watershed's natural spatial variability, (2) the technique for delineating HRU's accommodates different classification criteria and is reproducible, and (3) HRU's are not limited by hydrographic-subbasin boundaries. HRU's so defined are spatially noncontiguous. The result is an objective, efficient methodology for characterizing a watershed and for delineating HRU's. Also, digital data can be analyzed and transformed to assist in defining parameters and in calibrating the model.     

WATER SUPPLY AND WASTEWATER DISPOSAL IN RURAL AREAS OF INDIA1

ABSTRACT: Piped water supply and sewerage have been taken almost for granted in the developed countries. However, most people in the United States have little knowledge of the condition of public health amenities in the developing countries. The paper reviews the importance, background and current status of water and wastewater facilities in India. The relative situation in urban and rural areas, conventional practices in environmental hygiene, the programs for improvement and the problems involved with possible solutions are given. The case history of a town is also included for illustrative purposes.     

城市生活垃圾的生命周期管理

根据国际标准化组织１９９７ 年颁布的ＩＳＯ１４０００ 环境管理体系“生命周期评价—原则与框架”,本文对可持续城市生活垃圾生命周期管理进行研究,指出城市生活垃圾应在环境可持续性、经济可负担性及社会可接受性的原则基础上,通过垃圾的减量化、无害化、资源化和社会化管理,实现城市可持续发展的管理目标     

区域化变量理论在历史洪涝灾害空间格局重建中的应用──以长江流域1736-1911年洪涝灾害为例

通过构造一个例子,简介了区域化变量理论的基本原理、计算过程及其在洪涝灾害空间格局重建中的优点。依据区域化变量理论,以长江流域1736～1911年洪涝灾害为实例,重建了长江流域历史时期洪涝灾害的基本空间格局．     

Spatial Pattern of Ecosystem Function and Ecosystem Conservation

The spatial pattern of ecosystem function can affect ecosystem conservation. Ecosystem functions are often heterogeneous spatially due to physical and biological factors. We can influence ecosystem functions by changing the spatial patterns of the physical and biological elements of an ecosystem and regulating their combinations. The variation–position effect highlights a phenomenon resulting from the spatial pattern of ecosystem function. The effect shows that the identical variation of a factor may produce different effects on the overall situation when this variation occurs in a different spatial position. In a watershed of the Yangtze River, water retention is a primary ecosystem function. The variation–position effect for water retention capacity occurs in the watershed because of the spatial heterogeneity in vegetation, soil, and slope. The change of vegetation that occurs in a complex can affect the overall situation of water retention, and the effect can be different due to the change occurring in the position holding different vegetation-soil-slope complex. To improve the ecosystem in the watershed and to meet the social needs for the ecosystem function of water retention, a strategy called ecosystem function and spatial pattern-based forest extension was proposed to conserve forests. The implementation of the strategy enables the watershed to attain the maximum effective increase in water retention capacity.     

论城市创新的生态思维--推动城市可持续发展的新思维

城市化是人类生产和生活方式转型的必然结果,由于城市建设过程中依照的是传统思维模式,导致各大城市均不同程度存在一定的城市病。因此要加强可持续发展生态思维的观念,以期推动我国城市生态化与可持续城市建设工作的开展。     

公众参与市容环境规划与管理的方法设计--以南京市的实践为例

市容环境是与公众生活联系最为紧密的领域,也是公众参与最容易进行的领域。南京的城市建设要实现“经济发达、环境优美、融古都特色和现代文明于一体的现代化江滨城市”的目标,公众参与市容环境的规划与管理是关键内容之一。论文以“南京市市容环境卫生发展规划”项目工作为基础,分析和阐述公众参与的内涵,提出公众参与市容环境的五大步骤,并针对南京市容环境方面的具体案例,设计出符合南京特色的公众参与市容环境规划与管理的方法框架模型,包括决策模式、制度框架的共管体系。     

阜康市生态旅游规划研究

生态旅游规划是生态示范区规划的重要组成部分。本文以天池风景区规划为例阐述生态旅游规划应突破以风景区为主单一的旅游景观格局,应根据景观生态学原理、旅游地理学和旅游经济学理论,按照景观格局的梯度性变化为依据,以增长旅游线路、丰富景区类型、提高旅游收入为内容,以保护景区资源、开发景区资源为目标,开展基于发展“大旅游”思想的以沈域为单元的全面战略性规划,为实现阜康产业结构调整、增强区域经济实力提供依据。     

Numerical Prediction of Dispersion Characteristics in an Urban Area Based on Grid Refinement and Various Turbulence Models

A detailed simulation of the Goettinger Strasse pollutantdispersion problem is performed using the CFD code CFX-TASCflow for different wind directions. Two turbulencemodels, the k- and the RSM are adopted on three gridrefinement levels. Besides the typical reference gridimplemented by the TRAPOS group, two different gridresolutions are introduced. The first refinement is in thewhole street canyon region on the x-y level, while thesecond one is local in all three directions. Validation ofall involved computational schemes is performed based onrelative available experimental data. The computed velocityfields and concentration contours imply that the typicalreference grid is a suitable choice for the velocityfields, while local grid refinement in all three directionsin a small region containing the receptor is required toupgrade the pollutant concentration results with modestadditional computational effort. Finally the RSM modelresulted in smaller concentration levels. The k-model compared to the RSM seems a more appropriate choiceto solve this particular problem.     

Atmospheric Levels of Nitrogen Oxides at a Greek Oil Refinery Compared with the Urban Measurements in Athens

Oil refining is among the industrial activities that emit considerable amounts of air pollutants into the atmosphere. Nitrogen oxides are important air pollutants that are emitted by oil refineries as products of combustion processes. The ambient air concentrations of nitrogen oxide (NO) and nitrogen dioxide (NO₂) were monitored continuously at a site close to an oil refinery, near the city of Corinth in Greece, during autumn 1997 together with the main meteorological parameters. The contribution of the oil refinery to the measured atmospheric levels of nitrogen oxides was estimated. The ambient air concentration of nitrogen oxides in the area surrounding the oil refinery were generally lower than the ambient air concentrations in the urban area of Athens in Greece, and the NO₂ levels were always below the existing air quality standards. The influence of the refinery emitted NO_x in the photochemical production of ozone seems to be more important in terms of human and vegetation exposure given the high ozone backgrounds measured in the area.