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841.
Serveiss VB 《Environmental management》2002,29(2):145-154
Considerable progress in addressing point source (end of pipe) pollution problems has been made, but it is now recognized
that further substantial environmental improvements depend on controlling nonpoint source pollution. A watershed approach
is being used more frequently to address these problems because traditional regulatory approaches do not focus on nonpoint
sources. The watershed approach is organized around the guiding principles of partnerships, geographic focus, and management
based on sound science and data. This helps to focus efforts on the highest priority problems within hydrologically-defined
geographic areas. Ecological risk assessment is a process to collect, organize, analyze, and present scientific information
to improve decision making. The U.S. Environmental Protection Agency (EPA) sponsored three watershed assessments and found
that integrating the watershed approach with ecological risk assessment increases the use of environmental monitoring and
assessment data in decision making. This paper describes the basics of the watershed approach, the ecological risk assessment
process, and how these two frameworks can be integrated. The three major principles of watershed ecological risk assessment
found to be most useful for increasing the use of science in decision making are (1) using assessment endpoints and conceptual
models, (2) holding regular interactions between scientists and managers, and (3) developing a focus for multiple stressor
analysis. Examples are provided illustrating how these principles were implemented in these assessments. 相似文献
842.
东川市土地退化(荒漠化)及其防治 总被引:5,自引:0,他引:5
分析了东川市土地退化现状:土地退化以水蚀为主,退化土地面积占总土地面积38.5%。土地退化类型主要有土壤退化、土地沙石化、土地石质化和侵蚀劣地。文章还探讨了东川市土地退化的原因,提出了土地退化防治对策。 相似文献
843.
/ A watershed-based approach for screening-level assessment of nonpoint source pollution from inactive and abandoned metal mines was developed and illustrated. The methodology was designed to use limited stream discharge and chemical data from synoptic surveys to derive key information required for targeting impaired waterbodies and critical source areas for detailed investigation and remediation. The approach was formulated based on the required attributes of an assessment methodology, information goals for targeting, attributes of data that are typical of basins with inactive mines, and data analysis methods that were useful for the case study. The methodology is presented as steps in a framework including evaluation of existing data/information and identification of data gaps; definition of assessment information goals for targeting and monitoring design; data collection, management, and analysis; and information reporting and use for targeting. Information generated includes the type and extent of and critical conditions for water-quality impairment, concentrations in and loadings to streams, differences between concentrations in and loadings to streams, and risks of exceeding target concentrations and loadings. Data from the Cement Creek Basin, located in the San Juan Mountains of southwestern Colorado, USA, were used to help develop and illustrate application of the methodology. The required information was derived for Cement Creek and used for preliminary targeting of locations for detailed investigation and remediation. Application of the approach to Cement Creek was successful in terms of cost-effective generation of information and use for targeting.KEY WORDS: Water quality assessment; Nonpoint source pollution; Inactive mines; Watershed 相似文献
844.
/ A study was conducted to determine the extent of nitrogenpollution in agricultural lands in the Lower Fraser River basin of BritishColumbia, Canada. The specific objectives were to determine the distributionof leachable nitrogenand estimate the nitrogen concentration in groundwaterrecharges. Nitrogen and water mass balances were conducted on the entirebasin and on each of the four districts comprising it over the period1971-1991 in intervals of five years. The results indicated that the averagenitrogen concentration in the groundwater recharge for the entire basin rosefrom nondetectable in 1971 to 6 mg/liter in 1991. Estimates for theindividual districts ranged from 4 to 14 mg/liter in Central Fraser and fromnondetectable to 7 mg/liter in Fraser-Cheam and 3 mg/liter in both GreaterVancouver and Dewdney-Alouette. So far, excessive levels of nitrogen areconfined to Central Fraser. Although they have remained within the acceptablerange, nitrogen concentrations in the other three districts have definitelyincreased over the 20-year study period. Sensitivity analyses indicated thatanimal manure and fertilizer had the largest contribution in groundwaterrecharge. Decreasing the rate of manure application to agricultural lands issuggested as the most practical way of reducing nitrogen pollution in CentralFraser.KEY WORDS: Nitrogen balance; Water balance; Sensitivity analysis 相似文献
845.
高压水射流技术在清洗领域的应用,因其具有一系列优势,越来越为社会所认同和欢迎。以何种模式运行才能使其发展的更快、更好,是在该领域的工作者所普遍关注的问题。在理论与实践相结合的基础上,再次讨论并提出高压水射流清洗技术应用的专业化、规模化与社会化,以期在更大的范围引起同行的参与,共同寻求发展我国高压水射流清洗技术应用的最佳战略、策略和实施的方式。实践证明,高压水射流清洗技术应用的专业化、规模化与社会化是可以实现的。坚持为国民经济建设服务,使其专业化、规模化与社会化并逐步充实、完善,定能使之有更大的发展 相似文献
846.
我国水污染现状及防治对策 总被引:2,自引:1,他引:2
我国是一个水资料严重匮乏和水污染十分严重的国家,加强水污染管理和控制刻不容缓。为此,本文结合发达国家立法现状,从组织,民众意识、水污染排放标准,监测方法等方面论述加强水污染控制的管理。 相似文献
847.
本文论述了水土水流失对生态环境的影响和对农业生产的危害,阐明增强环境意识,加强水土保持时防止生态恶化,是我国振兴农业的重要性与紧迫性的任务。 相似文献
848.
849.
850.
John B. Braden Noelwah R. Netusil Richard F Kosobud 《Journal of the American Water Resources Association》1994,30(5):781-791
ABSTRACT: This paper summarizes key provisions of the Clinton Administration's proposals for change in the Clean Water Act. Two of the important themes for change are tougher controls for non-point source pollution and the use of market-based instruments. A detailed analysis of market-based abatement suggests limited potential for reducing costs. The keys to nonpoint source pollution control are clearer definition of property rights combined with changes in government programs that encourage polluting activities. 相似文献