BRINGING DOWN OUR DAMS: TRENDS IN AMERICAN DAM REMOVAL RATIONALES1

ABSTRACT: Over 76,000 dams have been constructed on American rivers to provide services such as flood protection, water storage, hydroelectric power, and navigation. Although most dams continue to provide sufficient benefits to retain the structure, dam removal is becoming increasingly common. This study involved the construction of a dam removal database to analyze spatial and temporal trends in dam removal. The data included information on 417 cases of dismantled American dams, 153 with known rationales for removal. Database analysis indicated that the leading purposes for dismantling structures are safety concerns and interest in environmental restoration. There is substantial geographic variability in dam removal rationales, with California leading in razing dams for environmental purposes, and Wisconsin leading in economic and safety rationales. States with substantial removals tend to have programs that support and fund dam razing. Although removals for safety reasons have been increasing steadily in the past three decades, environmental removals made a rather dramatic and sudden entry into the dam removal arena in the 1990s. Analysis of spatial and temporal trends in dam razing are of particular significance given the likely increase in dam removals in the 21st Century.     

THE STRUCTURE AND PRACTICE OF WATER QUALITY TRADING MARKETS1

ABSTRACT: The use of transferable discharge permits in water pollution, what we will call water quality trading (WQT), is rapidly growing in the U.S. This paper reviews the current status of WQT nationally and discusses the structures of the markets that have been formed. Four main structures are observed in such markets: exchanges, bilateral negotiations, clearinghouses, and sole source offsets. The goals of a WQT program are environmental quality and cost effectiveness. In designing a WQT market, policy makers are constrained by legal restrictions and the physical characteristics of the pollution problem. The choices that must be made include how trading will be authorized, monitored and enforced. How these questions are answered will help determine both the extent to which these goals are achieved, and the market structures that can arise. After discussing the characteristics of different market structures, we evaluate how this framework applies in the case of California's Grassland Drainage Area Tradable Loads Program.     

道路交通安全知识提取方法及其递进式模型的研究

道路交通数据资源日益膨胀和复杂化 ,已经远远超出了人脑的记忆和分析能力。面对道路交通的海量数据 ,传统运用的DBMS和OLTP技术 ,已无法发现隐藏在数据背后的关系、规则和发展趋势等新的内容、知识和信息。因此 ,建立基于DMKD的智能道路交通安全决策支持系统是相关部门急需解决的重大课题。笔者重点介绍了数据挖掘、知识发现的概念 ,提出了基于DW +OLAP +DMKD的道路交通安全决策支持系统 ,通过道路交通系统的要素分析 ,介绍了一种面向属性的粗糙集方法提取规则 ,并阐述了一种递进式规则评价提炼过程。     

从项目评价到战略评价

文章阐述了《环境影响评价法》立法的重大意义。     

USE OF THE DELPHI METHOD IN RESOLVING COMPLEX WATER RESOURCES ISSUES1

ABSTRACT: The tri‐state river basins, shared by Georgia, Alabama, and Florida, are being modeled by the U.S. Fish and Wildlife Service and the U.S. Army Corps of Engineers to help facilitate agreement in an acrimonious water dispute among these different state governments. Modeling of such basin reservoir operations requires parallel understanding of several river system components: hydropower production, flood control, municipal and industrial water use, navigation, and reservoir fisheries requirements. The Delphi method, using repetitive surveying of experts, was applied to determine fisheries' water and lake‐level requirements on 25 reservoirs in these interstate basins. The Delphi technique allowed the needs and requirements of fish populations to be brought into the modeling effort on equal footing with other water supply and demand components. When the subject matter is concisely defined and limited, this technique can rapidly assess expert opinion on any natural resource issue, and even move expert opinion toward greater agreement.     

模糊评价数学模型在企业安全评价中的应用

模糊评价是利用模糊数学的基本理论--隶属度将模糊信息定量化，再对其进行定量评价得出科学结论的一种方法。该方法运用较普遍。介绍了该方法的基本原理，通过实例论述了它在企业安全评价中的应用。     

RURAL HOUSEHOLD RESPONSE TO WATER CONTAMINATION IN WEST VIRGINIA1

ABSTRACT: About one-third of all West Virginians obtain domestic water from private water wells. In this research, mail and telephone surveys were used to investigate household responses to bacteria, mineral, and organic chemical contamination of domestic water supplies. Of households who were informed of contamination and acknowledged the problem, over 85 percent took action to avoid exposure to water contamination problems. The most common action was to clean and/or repair the water system (55.9 percent of valid surveys). Approximately 45 percent of households made investments of either a water treatment system, a new water source, or correction of contamination source. The average, annual economic cost of rural household actions was $320 for bacteria, $357 for minerals, and $1,090 for organic contamination. These economic costs represent a lower bound estimate for rural household willingness-to-pay (WTP) for a reduction in domestic water contamination from government action. On average, investment actions had lower annual economic costs than noninvestment actions of boiling and hauling water so that households who undertook investment actions in response to water contamination would have a lower WTP for government action to reduce water contamination. When effectiveness of water treatment systems was evaluated, treatment systems which require minimal household maintenance were found to reduce exposure to water contamination to safe levels as households intended when they installed the system. Treatment systems which were commonly ineffective included those which required continual maintenance (e.g., chiorinators) or were not designed to solve the contaminant problem for which they were purchased (e.g., filter systems for bacteria).     

唐山中厚板厂污水处理回用工程的财务分析

探讨了项目财务评价结果和项目敏感性分析技术的应用方法,为某公司唐山中厚板厂污水处理回用项目融资方案和运营方案的决策提供依据.介绍了唐山中厚板材有限公司废水回收利用工程项目概况;确定了该项目的基础数据,进行财务分析,这是进行后续敏感性分析的基础.对此项目进行敏感性分析,找出影响该项目收益的敏感性因素,为该项目执行时的风险管理提供一定依据.     

MULTICRITERION DECISION MAKING FOR FLOOD CONTROL OPERATIONS: THEORY AND APPLICATIONS1

ABSTRACT: Flood control operations are generally complex in nature, as they are often associated with a large quantity of uncertain factors in combination of noncommensurable criteria. It has been found that the use of fuzzy set theory coupled with multicriterion decision making (MCDM) methods is very promising. In this paper, a multicriterion fuzzy recognition model is established for flood control operations. A subjective preference and iterative weights method is proposed for weight assessment. First, an initial solution of criteria weights, which is directly analyzed from the selected alternatives, is obtained by using the proposed fuzzy recognition model. Then, according to their knowledge related to real time flood operations, operators may modify the initial weights if necessary. When the relative membership grades of alternatives belonging to all rankings are fixed, a defuzzification equation is used to calculate the rank feature value vector. Based on the rank feature value vector, one can evaluate the alternative set. Two flood operation cases are provided to illustrate the application of the proposed model. With the incorporation of the operator's knowledge related to flood operations, the proposed model is flexible in giving weights and realizes more practical flood control operations.     

基于FAHP-MODM的矿井通风系统可靠性综合评价

为了提高矿井通风系统可靠性评价的准确性,结合模糊层次分析法和多目标决策理论对矿井通风系统可靠性进行综合评价。基于人-机-环-管理系统构建评价指标并确定评价策略,确定各指标主观权重和客观权重,利用线性加权法确定综合评价值并通过实例分析矿井通风系统各观测点的可靠性,对其进行优劣排序并得出可靠性等级。评价结果表明,FAHP-MODM可对矿井通风系统可靠性做出准确的评价。