A NOTE ON AREAL RAINFALL DEFINITION

A discussion is presented of the likely sources of error in defining areal rainfall on a storm basis. These include the instrumental error, sampling fluctuations over the area, and network density. The analysis of dense raingage data provides some perspective of the magnitude of the errors that might be encountered from the natural variability of rainfall. Except for one watershed in Arizona, the coefficient of variation, based on a sample of storm totals from the individual gages in various size areas, remains relatively constant with increasing area for a particular storm. The error due to rainfall variability over the area is probably the most important and must be considered in experiments which attempt to resolve small-area hydrologic problems.     

Evaluating water quality investments using cost utility analysis

This study borrows concepts from healthcare economics and uses cost utility analysis (CUA) to select an optimum portfolio of water quality enhancement projects in Perth, Western Australia. In CUA, costs are handled via standard discounted cash flow analysis, but the benefits, being intangible, are measured with a utility score. Our novel methodology combines CUA with a binary combinatorial optimisation solver, known as a 'knapsack algorithm', to identify the optimum portfolio of projects. We show how water quality projects can be selected to maximise an aggregate utility score while not exceeding a budget constraint. Our CUA model applies compromise programming (CP) to measure utility over multiple attributes in different units. CUA is shown to provide a transparent and analytically robust method to maximise benefits from water quality remediation investments under a constrained budget.     

基于GIS的城市土地利用与交通网络一体化模型

在蓬勃发展的城市化进程中,一方面,城市交通需求迅速增长,交通运输供给能力不足成为制约区域经济快速发展的瓶颈;另一方面,在城市化进程中突出的景观标志--土地利用的变化包含着城市极其丰富的信息量,城市交通网络设计必然要求将城市土地利用与交通网络设计整合考虑.概述了土地利用与交通网络设计的关系,构建了一个基于GIS的城市土地利用与交通网络设计一体化模型 (LTGIS) ,同时对模型中的系统设计进行了论述,表明城市土地利用与交通网络设计是密切相关的.基于GIS的城市土地利用与交通网络设计一体化模型(LTGIS)的提出具有理论与实践的双重意义.     

RIVER BASIN SIMULATION MODELS: GUIDELINES FOR THEIR USE IN WATER RESOURCES PLANNING1

ABSTRACT: Simulation models constructed to estimate the physical and economic performance of alternative river basin development configurations have been widely used since the start of the Harvard Water Program in the early 1960's. These models have proved useful in choosing from among several potential river basin configurations, since they can rapidly evaluate each configuration's expected performance. However, when dealing with large scale river basin development projects, in which over 50 or 100 alternative reservoirs, irrigation areas, and other components must be considered, it is sometimes quite difficult to effectively use a simulation model to rapidly identify those combinations of projects which best satisfy the development objectives. The purpose of this paper is to describe how a simulation model was used in the analysis of a complex river basin development project in Eastern Europe, and how the problems of scale were confronted and solved. The author's experience on this projet is used to derive a set of general guidelines which may be helpful in other simulation studies.     

THE CENTRAL ARIZONA WATER CONTROL STUDY: A COMPARISON OF ALTERNATE PLANS USING CONCORDANCE ANALYSIS AND MULTI-DIMENSION SCALING1

ABSTRACT The Central Arizona Water Control Study (CAWCS) was initiated by the Bureau of Reclamation in 1978. The study attempted to identify and evaluate alternate water management schemes for Central Arizona. By 1981 a set of seven plans had been developed and for each an assessment on a number of economic, environmental, and social factors had been undertaken. This paper offers a formal procedure, using concordance analysis and multi-dimension scaling, to compare alternate plans using multiple factors in order to produce a classification of the attractiveness of the alternatives. Empirical data for the CAWCS are used to clarify the procedure. The results of the formal analysis are compared to those produced by the CAWCS. A critique of the formal procedure is offered, and it is suggested that it may have utility to assist in the collection of data as well as in the search for a best plan. The procedure allows a number of different types of sensitivity tests to be conducted.     

MERITS OF STATISTICAL CRITERIA FOR THE PERFORMANCE OF HYDROLOGICAL MODELS1

ABSTRACT: The performance of a hydrological model is usually assessed first by visual inspection of the measured and computed hydrographs. Numerous statistical criteria are available for numerical evaluations of model accuracy in each single year, in a particular season of the year, or in a sequence of years or seasons. In the last case, the problem of computing the overall result has to be considered. If too many criteria are used and the criteria are switched frequently, an assessment of a model's performance becomes difficult for a potential user. Therefore, this paper concentrates on just three criteria and their combined evaluation: The Nash-Sutcliffe coefficient, which compares the model computed discharge with the average measured discharge; the “coefficient of gain from daily means” in which a uniform average discharge is replaced by daily average discharges; and the volumetric difference between the total measured and computed runoff. The three criteria are combined in a three dimensional representation that allows intercomparisons of model performance in a single diagram.     

基于GIS的新疆库尔勒市耕地地力等级评价研究

以新疆库尔勒市为例,将利用测土配方施肥项目所取得的基础数据,筛选有机质、速效钾、有效磷、有效锌等可量化的指标作为评价指标。根据模糊数学理论和特尔斐法建立评价因子的隶属函数模型,利用层次分析法建立评价因子的层次分析模型。以ArcGIS统计分析模块和空间分析模块为平台,根据加法模型计算出耕地地力综合指数,划分耕地地力等级。评价结果基本符合当地实际。     

南通市大气降水中硫酸根的影响因素研究

随着环境空气污染的日益加重,研究硫酸根与降水中其他因子的相关关系对准确反映大气的质量状况具有重要意义.根据南通市2018年的降水监测数据,采用SPSS统计分析软件对降水中的硫酸根浓度与pH值、电导率以及常见阴、阳离子进行相关性分析,推断出离子的可能来源.通过多元线性回归模型可以对南通的硫酸根离子浓度进行预测.研究为南通...     

基于RS与GIS的规划用地生态适宜性评价

利用遥感影像获取研究区土地利用类型,并运用GIS空间分析功能,分析了影响开发区规划用地生态适宜性的7个因子,并以此对生态适宜性进行综合评价,得到了定量化的评价结果,为区域规划奠定了基础。     

NONPARAMETRIC STATISTICAL ANALYSIS OF ANNUAL PEAK FLOW DATA FROM A RECENTLY URBANIZED WATERSHED1

ABSTRACT. In order to demonstrate the feasibility of a nonparametric statistical application in investigating the hydrologic impact of the rapid land use change accompanying intense urbanization, annual maximum peak flow data from an actual example (the Northeast Branch Basin, a recently urbanized Washington, D.C., suburban watershed) were analyzed. Annual peak flow data from the Patuxent Basin above Unity, Maryland, a rural watershed in close proximity to the study area, were compared to data from the Northeast Branch for the Same period utilizing the Wilcoxon matched-pairs signed-ranks test. A change in central tendency of each series was noted at the 0.01 significance level; however, the change was negative in the rural basin and positive in the urbanized Northeast Branch Basin. This central tendency change was considered indicative of an average decrease in the size of rainstorms producing annual maximum peak discharges. Rainstorm data from the Northeast Branch Basin were divided into two equal periods (before urbanization and after) and the Wilcoxon test was applied. It was found that rainstorms producing maximum annual peak discharges in the urbanized period were indeed smaller than those in the prior period (0.01 level of significance); however, larger annual peaks were produced. It was concluded that nonparametric statistical methods can be used readily with conventional methods to isolate and clearly analyze the various problems in an actual urban hydrologic study.     

How to foster agroecological innovations? A comparison of participatory design methods

Facing contemporary environmental crisis implies fostering agroecological innovations that take into account local ecological regulations and rely on multiple stakeholders' innovation capacities. This paper draws on two fields of literature that remain unconnected so far: participatory approaches and design sciences. It proposes an analysis grid to support a reflexive analysis of cases of implementation of three participatory design methods: ComMod (Companion Modelling for concerted management of natural resources), Forage Rummy (simulation-based board game for designing farming systems) and KCP (collective design workshops to foster innovation). This analysis highlights key features of the methods in view of agroecological innovation challenges, focusing on knowledge management and organisation for exploration.     

THE MEASUREMENT OF IMPACTS IN SMALL WATERSHEDS FOR FLOOD CONTROL1

ABSTRACT: An analogue method of ex post evaluation is proposed as a method of measuring the effectiveness of small watershed projects in obtaining flood control and economic benefits. Two watersheds were compared on a “with vs. without” project basis by both direct and indirect measurement of economic benefits. Direct measurements indicated that small watershed flood control projects did not generate the expected economic benefits. However, the indirect measurements of the same watersheds using land value enhancement as a surrogate suggested that the expected economic benefits were reflected in differential land values. The economic efficiency of small watershed projects should be measured ex ante and ex post on a “with vs. without” project basis rather than on a “before vs. after” basis whether using direct or surrogate variables.     

GIS网络服务区分析在重庆市主城区夜间施工噪声投诉处置中应用

通过对重庆市主城区夜间施工噪声投诉处置现状分析,以主城区道路交通网络、环境监察机构分布等数据专题建模,采用G IS的网络服务区功能的分析结果,提出车辆调度合理化建议方案,为环境监察部门的夜间施工噪声投诉处置车辆部署调度提供辅助技术支持。     

基于GIS的哈密地区旅游资源分析与评价

按国家标准(GB/T18972—2003)对哈密地区旅游资源进行普查,并结合前人所获得的资料,在地理信息系统(GIS)的支持下,从资源的丰度、品质、空间结构和空间分布等方面评价了哈密地区旅游资源,总结出哈密地区旅游资源具有类型较丰富、分布不均衡、资源品质一般、特品级旅游资源缺乏;人文旅游资源在数量上占有绝对优势且特色明显,但自然旅游资源仍有较大开发潜力等主要特征。该分析与评价结果可为该地区决策的制定提供战略参考。     

基于GIS的茂县水资源开发利用信息管理评价系统设计

为了实现对茂县水资源的高效利用,将水资源开发利用评价的知识与地理信息系统结合在一起,设计出一个基于GIS的水资源开发利用评价系统,从而对茂县的水资源合理利用和加大开发提供一个有力支持,以满足对茂县经济社会发展的要求。本文对该系统的需求分析、系统结构、数据、系统各功能、系统实现进行了说明。     

基于GIS的泗县开发区土地集约利用评价研究

以安徽省泗县开发区为例,从土地利用状况、用地效益、管理绩效和可持续发展状况4个方面构建开发区土地集约利用评价指标体系,运用GIS技术、特尔斐法,选择评价模型确定权重后对泗县开发区进行土地集约利用评价,研究泗县开发区土地集约利用状况.结果显示,泗县开发区土地集约利用总体水平为中等集约利用,土地利用状况和用地效益度方面存在着一定问题.基于反映的问题,提出相应的措施.     

复杂电磁环境中电磁威胁度评估仿真软件设计

主要针对复杂电磁环境中的电子设备进行电磁威胁度的评估预测,建立了威胁度评估模型,设定了威胁度等级判定,并利用计算机技术将复杂电磁环境预测仿真进行了软件方面的设计与实现。     

ON THE EVALUATION OF OPERATIONAL CLOUD SEEDING PROJECTS1

ABSTRACT Operational cloud seeding projects, those designed to produce a desired change in the weather and that are nonexperimental in nature, continue to be pursued widely in the United States. A recurring question by scientists, project sponsors, and cloud seeders has been, “was the weather altered and if so, by how much?” Evaluation of such projects is now recognized as having scientific benefits, and a four-year study has addressed various techniques and statistical methods to perform evaluations and to learn more about how to modify the weather. Most such evaluations hinge on some type of space-time comparisons, but valid comparisons can be obtained only avoiding biases in the project design and operation. Through simulated changes in weather conditions, it was determined that the principal component regression techniques were used to evaluate selected rain and hail modification projects, revealing modification in certain projects and none in others. Various relevant issues have been examined such as use of other weather variables (covariates) to increase detection power, the validity of using historical data as controls for discrete operational periods, possible randomization options during cloud seeding operations, and analyses of individual rain events versus that based on monthly or seasonal units.