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181.
阐述了在降雨时金矿渣场浸渣中残留的氰化物及泥沙淋溶于雨水中,形成地表径流进入地面水,对地面水环境造成的污染影响。具体介绍了在降雨时,渣场地表径流量、径流中污染物排放量、地面水(湖泊)允许纳污量的预测模式的应用。可为一般工矿企业露天渣场废水预测及环境影响评价提供借鉴。 相似文献
182.
中国第三代地震烈度区划图发布施行,标志着我国地震设防法规进入了一个新的阶段。尤其是地震设防标准与抗震设计规范的统一和有机结合,使地震烈度区划能更好地直接服务于我国的国民经济建设。本文简要回顾了地震烈度区划图编制的发展过程,并着重说明了第三代地震烈度区划图的使用规定。最后还表述了对新编制区划图中江苏省部分的有关认识。 相似文献
183.
时洪清 《防灾减灾工程学报》1993,(3)
本文在简述金湖县地震地质构造背景和地震活动的基础上,依据多年的工程地质勘察成果,着重对城区影响震害的地质因素和场地土的物理力学指标进行分析,并对场地土抗震进行了评价。 相似文献
184.
Mark H. Eisenbies James A. Burger W. Michael Aust Steve C. Patterson 《Water, Air, & Soil Pollution: Focus》2004,4(1):217-233
The timing of forestry operations relative to weather conditions is a consideration in applying Forestry Best Management Practices (BMPs). Harvesting during different seasons can result in degrees of soil disturbance, the distribution of logging debris, and potentially future stand productivity. The purpose of this study is to examine the response of loblolly pine (Pinus taeda L.) stands after wet- and dry-weather harvesting combined with three site preparation treatments. A 20 × 20 meter grid was established in fifteen 20-year-old, 3.3-ha loblolly pine plantations in South Carolina. A census of soil physical disturbance and slash distribution was made after harvesting. Growth was measured on 1/125th-ha plots at ages two and five. Dry-weather harvested (DWH) sites were 91% undisturbed, and 9% compressed. Wet-weather harvested (WWH) sites were 41% undisturbed, and 59% disturbed. WWH sites averaged 9% bare soil, while DWH sites averaged 16% with 1 kg m-2 less logging residue; primarily in the form of heavy and light slash. At age five, the green-weight biomass of flat-planted DWH and WWH sites were 13.3 and 12.6 kg tree-1 respectively, and on the bedded DWH and WWH sites were 18.6 and 22.8 kg tree-1. Wet weather harvesting did not seem to adversely affect stand growth, and may have improved it. Due to a prolonged drought, bedding had a larger effect on WWH sites than DWH harvested sites. The effects of droughty conditions may be influencing treatment response on these highly productive sites; however, the long-term effects of harvesting on stand growth remain to be seen. 相似文献
185.
Furimsky E 《Environmental management》2002,30(6):0872-0879
Information on the type and amount of hazardous and toxic waste is required to develop a meaningful strategy and estimate
a realistic cost for clean up of the Sydney Tar Pond site which is located on Cape Breton, in the province of Nova Scotia,
Canada. The site covers the area of the decommissioned Sysco (Sydney Steel Corporation) plant. The materials of concern include
BTEX (benzene, toluene, ethylbenzene, and xylenes), PAH (polycyclic aromatic hydrocarbons), PCB (polychlorinated biphenyl),
and particulates laden with toxic metals, such as arsenic, lead, and others. The originally nontoxic materials such as soil,
blast furnace slag, and vegetation, as well as surface and ground waters, which were subsequently contaminated, must also
be included if they fail tests prescribed by environmental regulations. An extensive sampling program must be undertaken to
obtain data for an accurate estimate of the waste to be cleaned and disposed of. Apparently, 700,000 tons of toxic waste,
which is believed to be present on the site, may represent only a fraction of the actual amount. The clean-up of the site
is only part of the solution. Toxic waste has to be disposed of in accordance with environmental regulations. 相似文献
186.
187.
Biodiversity surveys are often hampered by the inability tocontrol extraneous sources of variability introduced intocomparisons of populations across a heterogenous landscape. If not specifically accounted for a priori, this noisecan weaken comparisons between sites, and can make itdifficult to draw inferences about specific ecologicalprocesses. We developed a terrain-based, paired-sitesampling design to analyze differences in aquaticbiodiversity between streams draining eastern hemlock (Tsuga canadensis) forests, and those draining mixedhardwood forests in Delaware Water Gap National RecreationArea (USA). The goal of this design was to minimize variancedue to terrain influences on stream communities, whilerepresenting the range of hemlock dominated streamenvironments present in the park. We used geographicinformation systems (GIS) and cluster analysis to define andpartition hemlock dominated streams into terrain types basedon topographic variables and stream order. We computedsimilarity of forest stands within terrain types and usedthis information to pair hemlock-dominated streams withhardwood counterparts prior to sampling. We evaluated theeffectiveness of the design through power analysis and foundthat power to detect differences in aquatic invertebratetaxa richness was highest when sites were paired and terraintype was included as a factor in the analysis. Precision ofthe estimated difference in mean richness was nearly doubledusing the terrain-based, paired site design in comparison toother evaluated designs. Use of this method allowed us tosample stream communities representative of park-wide forestconditions while effectively controlling for landscapevariability. 相似文献
188.
Jeffrey L. Arthur Robert G. Haight Claire A. Montgomery Stephen Polasky 《Environmental Modeling and Assessment》2002,7(2):81-89
Two approaches to formulating the reserve site selection problem when species occurrence data is probabilistic were solved for terrestrial vertebrates in a small set of potential reserve sites in Oregon. The expected coverage approach, which maximizes the sum of the occurrence probabilities, yielded solutions that covered more species on average in Monte Carlo simulations than the threshold approach, which maximizes the number of species for which the occurrence probability exceeds some threshold. 相似文献
189.
Daniel L. Tufford William D. Marshall 《Journal of the American Water Resources Association》2002,38(6):1625-1635
ABSTRACT: This study presents the results of fecal coliform (FC) sampling in the Rawls Creek, South Carolina, watershed during 1999 and 2000. The work was undertaken because the watershed is listed on the 303(d) list for South Carolina due to FC excursions. The watershed is 43.8 percent residential, 35 percent forest, 5.7 percent mixed urban, 4.9 percent commercial, and 4.8 percent agriculture. Samples were taken at 15 stations during eight field trips divided into two phases to characterize FC inputs from subbasins and to integrate results from upstream sampling. FC concentrations ranged from 135 to 730 colonies/100 ml. Results suggest that retention ponds in the area are a significant factor in attenuation of FC concentrations. Catchments with the largest contiguous impervious areas are the greatest source of FC. The highest concentrations of FC were observed at stations just downstream from a large detention basin that intercepts storm runoff from a large commercial area. Further analysis of the design and performance of that structure is suggested. The Koon Branch tributary is less than 20 percent of the land area in the watershed but may contribute 40 percent of the fecal loading. The results of this study confirm the importance of site assessments to aid understanding of nonpoint source pollution in complex watersheds. 相似文献
190.