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ZHANG Yuxin FENG Shangyou Wuhan University of Hydraulic Electric Engineering The English text is edited by Dr Ding Lianzhen 《国际泥沙研究》1993,(1)
I. INTRODUCTIONReservoir operation study in planning stage is an important task for the water resourcesdevelopment design. In the past. much attention has been paid to making the most ot' floodcontol. power generation, navigation. and water supply, but less to the unfavorable effectsdue to reservoir sedimentation. According to the survey of 425 reservoirs in Japan with a total storage capacity of 13.2 billion mJ a volume of 825 million m3 of sediment was depositedby the end of 1979. This… 相似文献
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"5·12"汶川地震房屋建筑震害分析与对策研究报告 总被引:2,自引:0,他引:2
"·"汶川地震房屋震害研究专家组 《四川地震》2009,(2)
2008年5月12日14时28分,四川省汶川县境内发生了里氏8.0级特大地震,地震造成重大人员伤亡和经济损失.地震发生后,在国家建设部等有关部委支持下,在四川省委、省政府的统一部署下,四川省建设系统和地震系统等迅速组织相关专家和工程技术人员前后共计2500余人次,持续时间达2个多月,深入灾区开展地震震害调查、房屋安全应急评估、专项房屋结构技术鉴定和技术人员培训等工作,掌握了较丰富的房屋震害第一手调查评估资料. 相似文献
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NIU ZhenGuo GONG Peng CHENG Xiao GUO JianHong WANG Lin HUANG HuaBing SHEN ShaoQing WU YunZhao WANG XiaoFeng WANG XianWei YING Qing LIANG Lu ZHANG LiNa WANG Lei YAO Qian YANG ZhenZhong GUO ZiQi & DAI YongJiu State Key Laboratory of Remote Sensing Science Jointly Sponsored by Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing Normal University Beijing China School of Geography Beijing Normal University Beijing 《中国科学D辑(英文版)》2009,52(6):723-738
In this paper, we report the first wetland mapping of the entire China using Landsat enhanced thematic mapper plus (ETM+) data. These data were obtained from the Global Land Cover Facility at the University of Maryland spanning from 1999 to 2002. A total of 597 scenes of Landsat images were georeferenced and mosaiced. Manual image interpretation of satellite images was aided with elevation data, soil data, land cover/land use data and Google Earth. The minimum mapping unit is 10 pixel × 10 pixel, equivalent... 相似文献
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Energy Optimization of Well Fields 总被引:1,自引:0,他引:1
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Cross-correlation analyses on field data collected in karst aquifer systems can be used to develop a conceptual understanding of the aquifer. This includes the use of many data sets from the same aquifer to develop an understanding of how properties vary spatially. We focus on a method for characterizing the distribution of recharge, which is becoming increasingly important in regions where urban development encroaches on these important sources of water. Spatially varying precipitation data and cross-correlation analysis provide a means of spatially characterizing recharge locations on a karst aquifer. Our work expands on the numerical experiments conducted by Padilla and Pulido-Bosch (1995) using the numerical ground water model MODFLOW to introduce spatially varying parameters. The numerical experiments include conduit-controlled, matrix-controlled, and mixed karst systems with more than one precipitation time series input. The results show that spatially varying parameters can be inferred based on the cross-correlation of precipitation data and spring discharge. Simulations were completed using aquifer parameters derived from studies of the Barton Springs segment of the Edwards Aquifer. The simulations indicate that spatial variability within an aquifer can be inferred using cross-correlation analysis. A field study using these methods is summarized for Barton Springs near Austin, Texas. 相似文献
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Distinguishing Iron-Reducing from Sulfate-Reducing Conditions 总被引:2,自引:0,他引:2
by Francis H. Chapelle Paul M. Bradley Mary Ann Thomas and Peter B. McMahon 《Ground water》2009,47(2):300-305
Ground water systems dominated by iron‐ or sulfate‐reducing conditions may be distinguished by observing concentrations of dissolved iron (Fe2+) and sulfide (sum of H2S, HS?, and S= species and denoted here as “H2S”). This approach is based on the observation that concentrations of Fe2+ and H2S in ground water systems tend to be inversely related according to a hyperbolic function. That is, when Fe2+ concentrations are high, H2S concentrations tend to be low and vice versa. This relation partly reflects the rapid reaction kinetics of Fe2+ with H2S to produce relatively insoluble ferrous sulfides (FeS). This relation also reflects competition for organic substrates between the iron‐ and the sulfate‐reducing microorganisms that catalyze the production of Fe2+ and H2S. These solubility and microbial constraints operate in tandem, resulting in the observed hyperbolic relation between Fe2+ and H2S concentrations. Concentrations of redox indicators, including dissolved hydrogen (H2) measured in a shallow aquifer in Hanahan, South Carolina, suggest that if the Fe2+/H2S mass ratio (units of mg/L) exceeded 10, the screened interval being tapped was consistently iron reducing (H2~0.2 to 0.8 nM). Conversely, if the Fe2+/H2S ratio was less than 0.30, consistent sulfate‐reducing (H2~1 to 5 nM) conditions were observed over time. Concomitantly high Fe2+ and H2S concentrations were associated with H2 concentrations that varied between 0.2 and 5.0 nM over time, suggesting mixing of water from adjacent iron‐ and sulfate‐reducing zones or concomitant iron and sulfate reduction under nonelectron donor–limited conditions. These observations suggest that Fe2+/H2S mass ratios may provide useful information concerning the occurrence and distribution of iron and sulfate reduction in ground water systems. 相似文献