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21.
22.
公路建设加速了区域的原有侵蚀,为了摸清公路边坡的侵蚀特征,寻找有效的防治措施,在青藏公路边坡布设不同水土保持措施的径流观测小区,进行了两年的观测(2003年和2004年),结果表明:(1)工程措施具有较好的水土保持效益,其减流(减沙)效益在第一年和第二年分别达到3883%(8189%)和48.72%(9581%),其中截排水措施的水土保持效益一方面说明公路路面来水也是边坡侵蚀的重要动力,有效拦截路面来水将会极大地减少径流和泥沙,另一方面也说明要提高公路边坡土壤侵蚀的预测能力,应该将路面来水作为重要的驱动力之一;(2)植被措施可以起到一定的减流减沙效果,其中人工植被措施有很大的潜力,其减蚀效益都在50%以上;(3)综合措施表现出了极好的水土保持效益(减流在40%以上,减沙在97%以上),尤其土工格室+植被措施,兼具水土保持与景观双重效益。该研究可以为青藏高原地区的水土保持设计和生态环境保护规划提供数据支持。〖 相似文献
23.
Modelling vegetation greenness responses to climate variability in a Mediterranean terrestrial ecosystem 总被引:2,自引:0,他引:2
Accurate knowledge of the quality and environmental impact of the highway runoff in Pear River Delta, South China is required
to assess this important non-point pollution source. This paper presents the quality characterization and environmental impact
assessment of rainfall runoff from highways in urban and rural area of Guangzhou, the largest city of Pear River Delta over
1 year’s investigation. Multiple regression and Pearson correlation analysis were used to determine influence of the rainfall
characteristics on water quality and correlations among the constituents in highway runoff. The results and analysis indicates
that the runoff water is nearly neutral with low biodegradability. Oil and grease (O&G), suspended solids (SS) and heavy metals
are the dominant pollutants in contrast to the low level of nutrient constituents in runoff. Quality of highway runoff at
rural site is better than that of at urban site for most constituents. Depth and antecedent dry period are the main rainfall
factors influencing quality of highway runoff. The correlation patterns among constituents in highway runoff at urban site
are consistent with their dominant phases in water. Strong correlations (r ≥ 0.80) are found among chemical oxygen demand (COD), total phosphorus, Cu and Zn as well as conductivity, nitrate nitrogen
and total nitrogen. O&G, COD, SS and Pb in highway runoff at urban site substantially exceed their concentrations in receiving
water of Pear River. The soil directly discharged by highway runoff at rural site has contaminated seriously by heavy metals
in surface layer accompanying with pH conversion from original acidic to alkaline at present. 相似文献
24.
Kenneth G. Maxey Norman H. Starler 《Journal of the American Water Resources Association》1987,23(5):749-759
ABSTRACT: In the past, development of Federal water resource projects depended heavily or exclusively on Federal financing of construction costs. However, pressures on the Federal budget, environmental issues, and the notion that there are economic efficiency gains when beneficiaries of Federal water resource projects increase their cost share are causing changes. The case of the Central Arizona Project Plan 6 is a noteworthy example of the transition to more non-Federal participation in water resource development. This is because the non-Federal financing is to be provided for a project already under construction. The negotiation and terms of the Plan 6 financing agreement between the Department of the Interior and multiple interests in Arizona are used as an example of how Federal water project cost sharing is in a state of transition. The negotiation process is described, a financial analysis is provided, and the terms of the agreement and policy issues that were deliberated in the Executive Branch of the Federal Government are discussed. 相似文献
25.
青龙满族自治县被列为河北省桃林口水库上游重点治理区,境内大量“四荒”资源闲置浪费。该县立足县情,制定优惠政策,强化管理,因地制宜地开发这些资源,取得显著成效,其做法值得推广和借鉴。 相似文献
26.
Current political conditions, primarily budgetary uncertainty, and the related reluctance to make funding commitments for
future generations, have raised questions about the costs of conservation and environmental protection that have not previously
been asked. As Federal investments are scrutinized and budgets become ever more constrained, the costs associated with environmental
requirements could begin to be of greater importance and to influence decisions on Federal projects. In response to concerns
about the U.S. Army Corps of Engineers (Corps) spending under the Endangered Species Act (P.L. 93-205) (ESA), a limited investigation
was performed to determine the accuracy of reported Corps expenditures. The investigation showed that, for particular groups
of species, actual conservation costs for threatened and endangered species may be twice the amounts previously reported in
the annual ESA expenditure reporting to the U.S. Fish and Wildlife Service. In light of this finding, the Corps has sought
a means to provide more accurate and consistent reporting of expenditures for addressing threatened and endangered species.
A Species Costs Template (template) has been developed to identify the types and magnitude of costs related to the ESA and
to counteract the impediments (legal, institutional, and practical) to underreporting costs. The template will be used by
the Corps for reporting ESA costs beginning with Fiscal Year 2005 (FY05) (reported in January 2006). Five broad categories
of expenditures (effects determination costs, ESA protection and conservation costs, equipment costs, opportunity costs, and
other species costs) are identified by the template. 相似文献
27.
Michael M. Reddy Kotra V. Krishnamurty Eugene Shpirt G. Anders Carlson Leo Hetling 《Environment international》1982,7(5):315-323
Total and particulate metal concentrations, measured during intensive synoptic studies of the Genesee River, NY, correlated with suspended-sediment concentration and river discharge. Dissolved metal concentrations, on the other hand, showed little systematic variation over the length of the river. Metal and sediment fluxes for two elevated-discharged periods peaked at a midbasin sampling site. For most metals at most sampling sties particulate materials comprised over one-half of the total material. Comparison of particulate material metal concentrations, normalized to the measured suspended-sediment concentrations had with basinwide average values shows that sites having low suspended-sediment concentrations had high particulate material metal contents relative to the basin averages, while sites with high suspended-sediment concentration had low metal contents. These results are consistent with a metal transport mechanism in the Genesee River involving (1) a nearly constant dissolved component, (2) a fine acid-soluble component, and (3) a coarse component that is effectively a neutral diluent in the sediment. Chemical factors, such as sediment organic content, also appear to affect metal transport in the Genesee River. 相似文献
28.
谢茂康 《湖南环境生物职业技术学院学报》2005,11(4):371-376
随着计算机网络技术的迅猛发展以及经济一体化和统一国际市场的逐渐形成,包括供应商在内供需链管理已经成为企业生产经营管理的重要组成部分.MRPⅡ系统已经无法满足企业对资源管理的要求.于是,充分利用和管理整体资源的企业资源计划:ERP随之产生.文章主要介绍了ERP的基本概念、基本原理和核心思想并分析了ERP实施的必要性以及应用现状.在此基础上,着重研究和探索我国企业实施ERP失败原因并针对客观实际,提出解决方案. 相似文献
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