Prevention versus Treatment under Precautionary Regulation: A Case Study of Groundwater Contamination under Uncertainty

Policy discussions on agricultural pollution problems characterize prevention as more cost effective and precautionary than ex post treatment. We derive conditions under which treatment alone is more cost effective in situations involving multiple sources of emissions, multiple sites affected, and a commonly used precautionary approach to uncertainty. We also show that a greater degree of precaution can result in less reliance on prevention. An empirical case study indicates that treatment alone is the most cost-effective means of dealing with nitrate in most Maryland community water system wells. The use of leaching prevention measures is restricted to the most intensive poultry producing areas. The incremental cost of precaution is substantial.     

Estimating Willingness to Pay for Improved Water Quality in the Presence of Item Nonresponse Bias

This article deals with the problem of item nonresponse in contingent valuation surveys using a payment-card method, by applying a grouped-data sample-selection estimation technique that is capable of imputing the missing values conditional upon a respondent's decision to answer a willingness-to-pay question. The advantage of the technique lies in its ability to utilize all of the information in the sample, permitting a more efficient estimation in the presence of item nonresponse bias. The major determinants of willingness to pay appear to be household income, number of children, education, perception of existing water quality, and identification with environmental issues.     

小氮肥清洁生产实践

文章介绍了沅江市氮肥厂废水闭路循环、尾气回收、废渣综合利用等工程,并介绍了该厂的生产工艺、污染源分布及排污特点。     

Provision of Human Resources for Water Resources and Hydropower Projects——A case of CGGC

1.Management of Human Resources in ChinaGezhouba Construction Group Corporation1.1Brief Introduction of CGGCChina GeZhouBa Construction Group Corporation(hereinafterreferred to as CGGC)is a super huge enterprise subordinatedto StateAssets Supervision and Administration Commission of PRC.It main-ly conducts water conservancy project,hydropower project,thermalelectric power project,nuclear electric power station,industrial andcivil works,as well as other works state-ratified.It is fa…     

工程建设项目战略灵活性的实物期权评价

为了进一步提高项目价值,项目经理必须认识项目规划和管理的不确定性。传统的工程项目规划、预算和管理往往认为不确定性降低了项目的价值,并没有从中充分地挖掘增加项目价值的机会。实物期权方法就是利用战略灵活性来识别和把握在动态不确定中所隐蔽的项目价值。通过一个高速公路项目的案例来展示实物期权方法所带来的管理灵活性对评价和选择战略的重要意义。还讨论了实物期权应用中的一些问题,指出了今后研究的方向。     

钢板桩围堰在水位变动区和软弱地基中的应用

利用钢板桩作围堰,在水位变动区和软弱地基条件下,采取一定刚度的围护设施来满足深基坑的施工需要;成功地运用了一种既施工简便、节约材料又确保安全的围护结构。根据软土的特点和钢板桩的柔性特征,通过采用模拟基坑开挖过程,按照板桩墙围护结构的设计计算方法进行围堰设计,并通过实际施工中一定的控制措施和对围堰内力、变形监测,确保相邻建筑物和自身结构施工的安全。根据实际运用的效果监测表明,采用的钢板桩围堰,是可行而又较优的一种方案。     

公共投资建设项目决策建立听证制度探讨

公共投资建设项目的投入源自公共资源，项目的建设与公众利益息息相关，在项目决策中建立听证制度来广泛征求社会公众的意见具有重大的现实意义。本文分析了在公共投资建设项目决策中建立听证制度的作用，并从制定依据、制度形式、制订主体等八个方面对听证制度做了详细的探讨。     

河北省水利工程正效益分析

分析了河北省建国以来水利工程总体正效益，包括城市供水效益、农业灌溉效益、节水灌溉效益、治理盐碱土地效益、防止水土流失效益、防汛抗旱效益等。     

浅谈城市污水回用的主要途径

本文对城市污水经处理后回用的主要途径进行了综述，其中重点介绍了回用到工业上的用途及其可行性。