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821.
822.
我国城市周边规划建设用地利用探讨 总被引:2,自引:0,他引:2
随着我国城市面积的不断扩大,大量的郊区耕地成为或即将成为城市的建设用地,同时与城市建设相伴相随的建筑渣土的堆放已成为城市的一大问题,本文按照循环经济原则,提出利用规划期内即将建设的城市周边耕地资源建立供应城市建筑的制砖企业,同时利用取土坑填埋建筑渣土,建立城市物质的有效循环,实现城市建筑的循环经济。并对此物质循环方式做了生态经济的分析,也对此物质循环中存在的障碍提出了解决的方法。 相似文献
823.
Douglas S. Kenney Roberta A. Klein Martyn P. Clark 《Journal of the American Water Resources Association》2004,40(1):77-87
ABSTRACT: Drought conditions in the summer of 2002 prompted several cities along Colorado's Front Range to enact restrictions on outdoor water use, focusing primarily on limiting the frequency of lawn watering. The different approaches utilized by eight water providers were tracked to determine the level of water savings achieved, measured as a comparison of 2002 usage to 2000 to 2001 average usage, and also based on a statistical estimate of 2002 “expected use” that accounts for the impact of drought conditions on demand. Mandatory restrictions were shown to be an effective tool for drought coping. During periods of mandatory restrictions, savings measured in expected use per capita ranged from 18 to 56 percent, compared to just 4 to 12 percent savings during periods of voluntary restrictions. As anticipated, providers with the most stringent restrictions achieved the greatest savings. 相似文献
824.
Luanne Y. Steffy Angela L. McGinty Claire Welty Susan S. Kilham 《Journal of the American Water Resources Association》2004,40(5):1269-1275
ABSTRACT: Valley Creek watershed is a small stream system that feeds the Schuylkill River near Philadelphia, Pennsylvania. The watershed is highly urbanized, including over 17 percent impervious surface cover (ISC) by area. Imperviousness in a watershed has been linked to fish community structure and integrity. Generally, above 10 to 12 percent ISC there is marked decline in fish assemblages with fish being absent above 25 percent ISC. This study quantifies the importance of ground water in maintaining fish species diversity in subbasins with over 30 percent ISC. Valley Creek contains an atypical fish assemblage in that the majority of the fish are warm‐water species, and the stream supports naturally reproducing brown trout, which were introduced and stocked from the early 1900s to 1985. Fish communities were quantified at 13 stations throughout the watershed, and Simpson's species diversity index was calculated. One hundred and nine springs were located, and their flow rates measured. A cross covariance analysis between Simpson's species diversity index and spring flow rates upstream of fish stations was performed to quantify the spatial correlation between these two variables. The correlation was found to be highest at lag distances up to about 400 m and drop off significantly beyond lag distances of about 800 m. 相似文献
825.
Derek B. Booth James R. Karr Sally Schauman Christopher P. Konrad Sarah A. Morley Marit G. Larson Stephen J. Burges 《Journal of the American Water Resources Association》2004,40(5):1351-1364
ABSTRACT: Successful stream rehabilitation requires a shift from narrow analysis and management to integrated understanding of the links between human actions and changing river health. At study sites in the Puget Sound lowlands of western Washington State, landscape, hydrological, and biological conditions were evaluated for streams flowing through watersheds with varying levels of urban development. At all spatial scales, stream biological condition measured by the benthic index of biological integrity (B‐IBI) declined as impervious area increased. Impervious area alone, however, is a flawed surrogate of river health. Hydrologic metrics that reflect chronic altered streamflows, for example, provide a direct mechanistic link between the changes associated with urban development and declines in stream biological condition. These measures provide a more sensitive understanding of stream basin response to urban development than do treatment of each increment of impervious area equally. Land use in residential backyards adjacent to streams also heavily influences stream condition. Successful stream rehabilitation thus requires coordinated diagnosis of the causes of degradation and integrative management to treat the range of ecological stressors within each urban area, and it depends on remedies appropriate at scales from backyards to regional storm water systems. 相似文献
826.
刘旭阳 《中国环境管理干部学院学报》2004,14(1):17-19
为了使北京市城区基础建设与环境保护协调发展,将城市基础建设中的污染降低,具体分析了基础建设的特点和存在的环境问题,并提出对策,提倡在城区基础建设中发挥生态建设的作用。 相似文献
827.
In this paper we examine the reconstitution of the Emergency Operations Centre (EOC) after its destruction in the World Trade Center attack, using that event to highlight several features of resilience. The paper summarises basic EOC functions, and then presents conceptions of resilience as understood from several disciplinary perspectives, noting that work in these fields has sought to understand how a natural or social system that experiences disturbance sustains its functional processes. We observe that, although the physical EOC facility was destroyed, the organisation that had been established to manage crises in New York City continued, enabling a response that drew on the resources of New York City and neighbouring communities, states and the federal government. Availability of resources--which substituted for redundancy of personnel, equipment and space--pre-existing relationships that eased communication challenges as the emergency developed and the continuation of organisational patterns of response integration and role assignments were among the factors that contributed to resilience following the attack. 相似文献
828.
829.
中国城市综合减灾体系建设及其系统思考 总被引:3,自引:0,他引:3
从中国城市减灾现状分析入手,重点剖析城市减灾的可持续发展问题,并探讨了城市社会经济可持续发展中如何确立防灾减灾的地位.进而用系统科学思路研究城市综合减灾的体系建设问题,从一定意义上较为科学地解决了跨世纪的中国城市可持续发展的关键问题. 相似文献
830.
都市扩张与土地资源利用集约化:关于上海市城市发展模式的研究 总被引:11,自引:0,他引:11
随着我国经济的持续高速增长,人口向城市,尤其是大城市集中的趋势越来越明显,城市规模正在迅速膨胀。具体说来,主要体现在以下三个方面-城市占地面积的扩张;城市人口的膨胀;城市经济实力的增长。 相似文献