共查询到20条相似文献，搜索用时 687 毫秒
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2014年南水北调中线工程正式通水,汉江中下游区水文情势发生显著变化。定量评估汉江中下游区水文情势变化特征,可为此区域水资源可持续开发利用提供科学依据。以黄家港、皇庄、仙桃站1987—2019年流量和水位数据,采用距平分析法、Mann-Kendall趋势检验法以及Yamamoto突变检验法对年、月尺度流量和水位序列进行分析,并采用水文变化指标法分析中线调水前后水文特征值变化。结果显示：调水后汉江中下游区典型站年径流量和年水位均较调水前呈下降趋势;各水文特征值均发生较为显著变化,各站点月平均流量和水位、年极端流量和水位总体低于调水前;调水后径流年内分配趋于均匀化。表明南水北调中线调水工程对汉江中下游流量和水位产生了显著影响。 相似文献
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为研究南水北调中线工程调水前,汉江中下游的水量和水质本底特性及变化趋势,选择汉江中下游6个水文站及4个水质观测断面,采用数理统计、Mann-Kendall检验和Spearman秩次检验法,分别从水量和水质两个方面进行了分析。研究结果表明:(1)对比分析历史长序列流量资料,1999~2013年间汉江中下游地区处于偏枯期;(2)汉江中下游水量的年际变化较大,极值比介于2.7~3.3之间。水量年内各月分配变化也较大,汛期径流量占全年的63%~66%,非汛期仅占全年的34%~37%;(3)汉江中下游地区各水文测站的年均流量序列,总体上随时间变化的趋势均不显著,但经历了1980~1990的偏丰期及1990~2013的偏枯期;(4)汉江中下游地区的水质达标情况较好,大部分年份的水质均优于III类水质标准,且水质无显著的变化趋势。 相似文献
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引江济太调水工程加快了太湖及其周边水体的置换,增加了太湖流域水资源有效供给,改善了太湖及引江济太沿线水体水质,但由于引水通道望虞河东西两岸支流较多,影响了引江济太入湖效率。采用2002～2017年太湖流域水文水资源监测中心在望虞河干支流的监测资料,对引江济太入湖效率进行统计计算,分析了影响入湖效率的因子,认为工程调度和望虞河东西两岸分流量是关键影响因子,在此基础上有针对性地提出了两点提高入湖效率的调度建议。 相似文献
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延安市富县引葫济富调水工程,充分调蓄利用葫芦河的引水量和大申号川的天然径流量,合理调配区域水资源,有效改善区域供水环境条件。通过对调水工程设计的分析,从工程设计引水流量、工程等别、洪水标准、输水管线布置、泵站设计等方面提出优化设计思路,以期为类似工程提供借鉴。 相似文献
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为探究重要国际河流湄公河支流NamLik河在NamLik1-2水库建设后下游的生态水文情势变化,基于水库下游Hinheup水文站1980—2018年日平均流量数据、流域ERA5再分析气象数据以及NamLik流域地理信息数据,采用IHA＿RVA法定量分析水库运行后河流水文情势改变;基于SWAT模型分析了气候变化和水库调度对水库下游径流年内分配变化的贡献率。结果表明：（1）NamLik1-2水库建库后下游水文情势发生较大改变,整体水文改变度达79%,属于高度改变;下游河道流量年内分配变化显著,月均流量指标的水文改变度达到70.4%。（2）基于SWAT模型对无水库情景的天然径流还原结果,计算得到水库对径流汛期减少和枯季增加的贡献率分别为142%和71%,而气候变化的相应贡献率分别为-42%和29%,水库运行是引起下游径流年内分配变化的主要原因。 相似文献
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引汉济渭工程是破解陕西省关中地区水资源短缺瓶颈的重大水利工程,输配水干线工程是实现汉江水进入关中各个城市供水系统"最后一公里"的重要组成部分。通过对关中地区2030年水资源供需平衡分析,确定引汉济渭工程受水区供水对象和水量配置,根据引汉济渭工程供水对象的地理位置分布、输水方式、高程及水头等,提出输配水干线工程四种布局方案,通过比较各方案主体干线供水量比重,工程规模及与现有工程结合等方面,确定输配水干线工程布局方案三一次过渭为最优方案。 相似文献
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Guzel A. Danukalova Anatoly G. Yakovlev Eugenya M. Morozova Liliana I. Alimbekova 《Quaternary International》2007,160(1):17
A summary of published and unpublished materials on the stratigraphy of the Late Middle Pleistocene (Middle Neopleistocene according to the Russian stratigraphic scheme) of the Southern Urals region is given. Deposits of different origin in the regional stratigraphic units are characterized. The results of mammalian investigations provide the basis for the stratigraphical subdivision. Mollusca and palynology are used for the reconstruction of the palaeoenvironments. The stratigraphical positions of the main Middle Neopleistocene localities and precise definitions of the stratigraphical scheme of the Southern Urals region are discussed. The Southern Urals subdivisions are correlated with the Western European stratigraphical schemes (Holsteinian–Saalian interval). 相似文献
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Yu. V. Rostovtseva 《Lithology and Mineral Resources》2009,44(4):367-378
The sequential accumulation of middle Sarmatian sediments in the Taman Trough in the terrigenous and carbonate settings is considered. Six facies of the shallow-water basin are identified. The first half of the middle Sarmatian was marked by the accumulation of dominant clayey sediments. The formation of small serpulid-microbial bioherms took place under relatively deep conditions (upper part of the lower sublittoral zone). The terminal middle Sarmatian was dominated by the deposition of carbonates with a wide development of bacterial-algal mats. Their formation in the upper sublittoral setting below the base level of ordinary waves was intermittently disturbed by the enhanced influx of terrigenous material and accumulation of clays, as well as by the storm-induced roiling and bioturbation. 相似文献
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Bandar I. Ghassal Haytham El Atfy Victoria Sachse Ralf Littke 《Arabian Journal of Geosciences》2016,9(20):744
Organic geochemical characterization of cutting samples from the Abu Hammad-1 and Matariya-1 wells elucidates the depositional environment and source rock potential of the Jurassic and Lower Cretaceous successions and the Middle Miocene to Pleistocene section in the southern and eastern Nile Delta Basin. The burial and thermal histories of the Mesozoic and Miocene sections were modeled using 1D basin modeling based on input data from the two wells. This study reveals fair to good gas-prone source rocks within the Upper Jurassic and Lower Cretaceous sections with total organic carbon (TOC) averaging 2.7% and hydrogen index (HI) up to 130 mg HC/g TOC. The pristane/n-C17 versus phytane/n-C18 correlation suggests mixed marine and terrestrial organic matter with predominant marine input. Burial and thermal history modeling reveals low thermal maturity due to low heat flow and thin overburden. These source rocks can generate gas in the western and northern parts of the basin where they are situated at deeper settings. In contrast, the thick Middle Miocene shows fair source rock quality (TOC averaging at 1.4%; HI maximizing at 183 mg HC/g TOC). The quality decreases towards the younger section where terrestrial organic matter is abundant. This section is similar to previously studied intervals in the eastern Nile Delta Basin but differs from equivalents in the central parts where the quality is better. Based on 1D modeling, the thick Middle Miocene source rocks just reached the oil generation stage, but microbial gas, however, is possible. 相似文献
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Specific features of the mineral composition, physicochemical parameters, and technological properties of analcime-bearing rocks developed in the Middle Timan region are discussed. Based on the study of dressability of these rocks, a technology for their concentrating is proposed. Possibility of the application of analcime-bearing rocks from the Middle Timan region in different fields of human activity is shown. 相似文献
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[摘 要] 中扬子中侏罗统主要散布于中扬子前陆盆地各次级盆地中,应用现代沉积学、高分辨率层序地层学理论,结合露头岩性、古生物、沉积相分析等手段,发现中侏罗统主要为辫状河、辫状河三角洲或扇三角洲以及滨浅湖沉积体系,在不同区域,分别以花家湖组、沙溪庙组和千佛崖组地层命名。不同区域层序特征既有差异,又存在相似性。根据高分辨率层序地层学理论,将花家湖组、沙溪庙组和千佛崖组分别划分为4 个、4个和2个三级层序,局部地区还可细划四级层序,整个中侏罗统大致相当于1个二级层序。此层序地层格架的形成主要是受构造因素控制,即印支期以来中扬子地区发生强烈的构造变形和运动而形成复杂的盆山耦合体系,层序横向展布和纵向叠加于前陆盆地中。 相似文献
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New processing of part of the Europrobe's Seismic Reflection Profiling in the Urals (ESRU) reflection seismic data in the Middle Urals shows a southwest‐dipping Moho imbrication and crustal underthrusting that was not previously imaged. The area of thickening associated with it roughly coincides with a deepening of the Moho imaged by the GRANIT refraction data. This feature does not fit with the currently known Palaeozoic crustal architecture of the Uralides or with its geodynamic history. Geological data suggest that it is not related to a relict southwest‐dipping subduction zone. Based on its lower crustal and Moho reflection seismic character it is presently interpreted to be a post‐Uralide feature, possibly related to Mesozoic intraplate shortening in the area. Its coincidence with a locus of mild earthquake activity further suggests that it might be active today. 相似文献
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《International Geology Review》2012,54(7):838-841
Karagandella kabanovii gen. et sp. nov. is described. It occurs, along with Pseudosporochnus nodosus and Lepidodendropsis kazachstanica, in sediments underlain by strata containing Stropheodonta sp., Schellwienella umbraculum, Atrypa sp.,Uncinulus grandis, and Mucrospirifer cf. mesacostalis. The overlying strata contain Stropheodonta sp., Schellwienella umbraculum, Longispina mucronata, Gypidula sp., Uncinulusdis, Elythyna sp., Spinocyrtia audacula, and Mucrospirifer cf.. mesacostalis. The occurrence is assigned to the lower part of the Akbastau suite, Givetian Stage, Middle Devonian, on the basis of the invertebrate fossils. Karagandella is questionably classed with the Protopteridiales or possibly with the Zygopteridales. It is a dorsiventrally flattened branching system in which the main rachis is straight, smooth, probably terete in cross-section, and monopodially branched. Secondary branches arise alternately or oppositely and almost at right-angles to the rachis. Ultimate segments are dichotomously branched and in some instances show circinnate vernation. Anatomy and reproductive structure are unknown. The plant is compared with Protocephalopteris and Rhacophyton on the basis of the similarity in branching and is differentiated from those genera by the absence of catadromic, sporangium-bearing, branching systems, pinnules (as in Rhacophyton), and its primitive appearance. The author suggests that Karagandella can be regarded as the prototype of the large fern frond. --F. M. Hueber. 相似文献