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121.
River channel network design for drought and flood control: A case study of Xiaoqinghe River basin, Jinan City, China 总被引:2,自引:0,他引:2
Baoshan Cui Chongfang Wang Wendong Tao Zheyuan You 《Journal of environmental management》2009,90(11):3675-3686
Vulnerability of river channels to urbanization has been lessened by the extensive construction of artificial water control improvements. The challenge, however, is that traditional engineering practices on isolated parts of a river may disturb the hydrologic continuity and interrupt the natural state of ecosystems. Taking the Xiaoqinghe River basin as a whole, we developed a river channel network design to mitigate river risks while sustaining the river in a state as natural as possible. The river channel risk from drought during low-flow periods and flood during high-flow periods as well as the potential for water diversion were articulated in detail. On the basis of the above investigation, a network with “nodes” and “edges” could be designed to relieve drought hazard and flood risk respectively. Subsequently, the shortest path algorithm in the graph theory was applied to optimize the low-flow network by searching for the shortest path. The effectiveness assessment was then performed for the low-flow and high-flow networks, respectively. For the former, the network connectedness was evaluated by calculating the “gamma index of connectivity” and “alpha index of circuitry”; for the latter, the ratio of flood-control capacity to projected flood level was devised and calculated. Results show that the design boosted network connectivity and circuitry during the low-flow periods, indicating a more fluent flow pathway, and reduced the flood risk during the high-flow periods. 相似文献
122.
伊犁河伊宁市段水质污染特征分析 总被引:3,自引:1,他引:2
在对伊犁河伊宁市段历年水质状况进行综合评价的基础上,探讨了城市河段水质的变化规律、污染特征和成因。 相似文献
123.
Monitoring urban growth and detecting land-cover changes on the Istanbul metropolitan area 总被引:1,自引:0,他引:1
Istanbul is the most populated city of Turkey with a population of around 10.58 M (2000) living on around 5,750 km2. In 1980, the population was only 4.7 M and then it has been more than doubled in only two decades. The population has been
increasing as a result of mass immigration. An urbanization process continues and it causes serious increases in urban areas
while decreasing the amount of green areas. This rapid, uncontrolled, and illegal urbanization accompanied by insufficient
infrastructure has caused degradation of forest and barren lands in the metropolitan area, especially through the last two
decades. The watershed basins inside the metropolitan area and the transportation network have accelerated the land-cover
changes, which have negative impacts on water quality of the basins. Monitoring urban growth and land cover change will enable
better management of this complex urban area by the Greater Istanbul Metropolitan Municipality (GIMM). A temporal assessment
of land-cover changes of Istanbul has been documented in this study. The study mainly focuses on the acquisition and analysis
of Landsat TM and Landsat GeoCover LC satellite images reflecting the significant land-cover changes between the years of
1990 and 2005. Raster data were converted to vector data and used in Geographic Information Systems (GIS). A database was
created for Istanbul metropolitan area to plan, manage, and utilize statistical attribute data covering population, water,
forest, industry, and topographic position. Consequently an overlay analysis was carried out and land use/cover changes through
years have been detected for the case study area. The capability of Landsat images in determining the alterations in the macro
form of the city are also discussed. 相似文献
124.
Klopchin JL Stewart JR Webster LF Sandifer PA 《Environmental monitoring and assessment》2008,137(1-3):301-313
Morgan Island, located within the ACE Basin National Estuarine Research Reserve in South Carolina, is home to the only free-ranging
colony of rhesus monkeys (Macca mulatta) in the continental United States. The purpose of this study was to assess environmental impacts of the monkey colony on
water quality in adjacent tidal creeks and on island vegetation. Three tidal creeks were sampled: Morgan Creek, adjacent to
the monkey colony; Back Creek, on Morgan Island not adjacent to the colony; and Rock Creek, on a nearby island unoccupied
by monkeys. Temperature, salinity, pH, dissolved oxygen, nutrients and fecal coliform bacteria were measured six times at
three sites in each of these creeks, and vegetation change analysis was conducted in a geographic information system using
satellite imagery. Results showed elevated fecal coliform concentrations in the Morgan Creek site immediately adjacent to
the colony, though no samples exceeded the standard set for recreational water use. Ribotyping reconnaissance matched four
Escherichia coli isolates from Morgan and Back Creeks to the monkeys, identifying the colony as one source of fecal coliform bacteria, though
relative source loadings could not be quantified. Significant differences were not observed between ammonia or orthophosphate
levels in Morgan Creek relative to the other creeks tested; and vegetation change analysis showed a 35% increase in canopy
cover between 1979 and 1999. Overall, these results suggest that the rhesus colony’s environmental impacts are localized and
minimal. Results from this study provide baseline data on Morgan Island and may be useful in management decisions regarding
the future of the monkey colony. 相似文献
125.
关于“四沿”化工安全的战略性思考与探索 总被引:3,自引:1,他引:2
以基本能浓缩中国化工概貌的江苏省沿江、沿河、沿湖、沿海化工企业为背景,依据其形成和发展及基本概况,结合重大化工事故灾难,以安全与环境相耦合,对"四沿"化工安全进行了战略性思考,试图勾画临水化工本质安全的模型,提出在"四沿"地区构建化工本质安全化科技支撑体系的宏观构架,即建设"江苏省四沿区域化工本质安全和化工事故防范及应急系统"的思路、探索与实践。还提出了立法深化研究和技术标准制定、严格区域规划设计与建设的监督、强化监管执法力度等急需关注的问题。以江苏省"四沿"区域的化工安全为背景所提出的思路与对策,应该对整个华东地区乃至全国临水性化工企业安全具有重要的现实和借鉴意义,对我国高危行业的安全生产和环境保护有重大的示范效应。 相似文献
126.
The measurement of the bed shear stress along vegetated river beds is essential for accurately predicting the water level, velocity and solute and sediment transport fluxes in computational hydroenvironmental models. Details are given herein of an experimental and theoretical study to determine the bed boundary shear stress along vegetated river beds introducing a novel field measuring method, namely the FliessWasserStammtisch (FST)-hemispheres. Although investigations have been conducted previously for sedimentary channels using the FST-hemispheres, this preliminary study is thought to be the first time that such hemispheres have been used to investigate the bed shear stresses in vegetated channels. FST-hemispheres were first developed by Statzner and Müller [1989. Standard hemispheres as indicators of flow characteristics in lotic benthos research. Freshwater Biology 21, 445-459] to act as an integrated indicator of the gross hydrodynamic stresses present near the bed. Test and validation data were found to be at least of the same order of magnitude for the stresses predicted from literature for sedimentary channels, with this study establishing the commencement of a database of calibrated FST-hemisphere laboratory data for vegetated channel beds. In a series of experiments, depths ranging from 0.1 to 0.28m were considered, equating directly to comparable conditions in small rivers or streams. The results of this study provide a basis for enabling the FST-hemispheres to be used to evaluate the boundary shear stress for a wider range of applications in the future, including vegetated river beds. 相似文献
127.
黄河水体沉积物对敌百虫和甲拌磷的吸附 总被引:8,自引:0,他引:8
对敌百虫和甲拌磷在黄河水体沉积物中的吸附特性进行了研究,观察了pH值和离子强度等因素对吸附的影响.结果表明,敌百虫的吸附过程为一级动力学规律;敌百虫的吸附符合Langmuir等温式,甲拌磷的吸附可用Freundich等温式较好地描述.ph值降低或离子强度增加使敌百虫和甲拌磷在沉积物中的吸附程度明显减小.敌百虫在黄河水体沉积物中的吸附以表面吸附为主,而甲拌磷则表现为表面吸附和在有机碳中的分配作用两种吸附方式. 相似文献
128.
129.
基于主成分分析-多元线性回归的松花江水体中多环芳烃源解析 总被引:2,自引:1,他引:1
对松花江全流域14个监测断面的16种美国环保局优先控制的多环芳烃(PAHs)的主要来源及其贡献率应用主成分因子分析-多元线性回归模型(PCA-MLR)进行了来源解析。结果表明:松花江全流域为化石和石油燃料的复合PAHs污染,水体环境中PAHs首要污染源为化石燃料燃烧和交通污染,合计贡献率为63.1%,第二大污染源为工业和民用燃煤污染,合计贡献率为36.9%,沿江的石化、石油基地、大型焦化厂、电厂都是PAHs的主要来源。 相似文献
130.