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为揭示黄河口清水沟河道长时段的冲淤演变规律并建立其冲淤计算方法,分析了清水沟1976—2015年的时空冲淤演变过程,采用河床演变的滞后响应模型,考虑河口来水来沙及河道延伸与蚀退的影响,建立了清水沟累计冲淤量的计算方法。结果表明:1976—1980年改道初期清水沟改道点上游先冲后淤,改道点下游淤滩塑槽,淤积量随着下游河道展宽而增加,1980年后改道点上、下游河道冲淤过程趋于一致;受水沙条件等因素影响,1980—1986年清水沟主槽冲刷展宽,之后主槽淤积萎缩;1996年清八改汊和2002年小浪底水库"调水调沙"原型试验以来,河道转淤为冲,2002年后河道冲刷速率随时间指数衰减;河床演变的滞后响应模型可计算清水沟长时段的冲淤过程,该方法可为预测未来清水沟冲淤演变趋势提供科学参考。 相似文献
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黄河口清水沟流路先后经历了游荡型,顺直型和弯曲型和河床演变阶段。与此同时,河流的冲淤变化经历了摆动淤积,造床冲刷和延伸淤积三个阶段,这些变化对河床纵剖面,水位和险情带来了某些较深刻的影响。 相似文献
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在南祁连清水沟一带,盐池湾组呈北西西-南东东向展布．为一套深灰绿色细碎屑浊积岩系夹深海泥岩。主要岩性有变泥质粉砂岩、长石石英杂砂岩、细砂质长石石英粉砂岩、长石杂砂岩、绢云石英千枚岩等。岩石中粒序层理、交错层理不太发育,指示该组岩层层序是倒转的．即北老南新。该组发育不完整鲍玛层序,有3种类型．即ABCD型、韵律型和均一型。综合研究盐池湾组的宏观岩性特征、基本层序、沉积构造、浊流沉积岩石学特征、粒度曲线特征、微量元素、稀土元素指数等蕴藏在沉积岩中的各种地质信息,指示该组形成于次深海至深海相浊流沉积中端相和远端相区。浊积岩与深海泥岩以不同比例重复组合,构成复理石沉积建造。 相似文献
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该论文对箐水沟稀土矿区域地质背景,矿区含矿地层、控矿构造、岩浆岩、变质作用、矿体特征、矿石矿物组成、矿石化学成分及伴生元素、稀土元素的赋存状态,找矿标志等进行了研究。总结了区内氟碳铈矿型稀土矿的控矿因素主要有地层、构造、岩浆岩、围岩蚀变等。矿区及其外围成矿地质条件良好,通过进一步工作可望找到较大的稀土矿。 相似文献
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黄河清水沟流路河口三角洲增长面积预测 总被引：5，自引：0，他引：5
根据历年卫片解译和海区实测水深资料,结合利津站水沙系列,建立了河口三角洲面积增长与水沙关系的模拟模型,经过效果检验,选择出理想的预测模型,然后,根据未来河口地区水沙变化特点,预测了河口三角洲面积的增长。 相似文献
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Delta channels are important landforms at the interface of sediment transfer from terrestrial to oceanic realms and affect large, and often vulnerable, human populations. Understanding these dynamics is pressing because delta processes are sensitive to climate change and human activity via adjustments in, for example, mean sea level and water/sediment regimes. Data collected over a 40-year period along a 110-km distributary channel of the Yellow River Delta offer an ideal opportunity to investigate morphological responses to changing water and sediment regimes and intensive human activity. Complementary data from the delta front provide an opportunity to explore the interaction between delta channel geomorphology and delta-front erosion–accretion patterns. Cross-section dimensions and shape, longitudinal gradation and a sediment budget are used to quantify spatial and temporal morphological change along the Qingshuigou channel. Distinctive periods of channel change are identified, and analysis provides a detailed understanding of the temporal and spatial adjustments of the channel to specific human interventions, including two artificial channel diversions and changes in water and sediment supply driven by river management, and downstream delta-front development. Adjustments to the diversions included a short-lived period of erosion upstream and significant erosion in the newly activated channel, which progressed downstream. Channel geomorphology widened and deepened during periods when management increased water yield and decreased sediment supply, and narrowed and shallowed during periods when management reduced water yield and the sediment load. Changes along the channel are driven by both upstream and downstream forcing. Finally, there is some evidence that changing delta-front erosion–accretion patterns played an important role in the geomorphic evolution of the deltaic channel; an area that requires further investigation. © 2020 John Wiley & Sons, Ltd. 相似文献
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黄河入海流路自1976年5月改道至清水沟流路以来,其地貌形态一直处于剧烈的变化当中,以往的研究虽然关注了典型断面主槽的形态特征及过流能力的变化,但对于清水沟流路范围界限内河道断面整体形态及其沿程变化等地貌特征还缺乏系统研究.本文以2019年10月黄河口现行清水沟流路范围渔洼以下河段加测横断面为研究对象,辨识现状地貌分布特点和横断面沿程形态特征,并分析其成因.结果表明:黄河口地貌形成受自然演变和人类活动的影响,既具有主槽、滩地、堤防等河流地貌要素,又具有滩涂、潮沟、拦门沙等海洋地貌要素.在有堤防河段,主槽形态窄深,过流能力较强;在无堤防河段,主槽形态宽浅,过流能力较差;从滩槽高差、唇滩高差、滩地横比降三个指标来看,无堤防河段的"自然悬河"程度大于有堤防河段的"二级悬河"程度.黄河口悬河程度小于黄河下游大部分河段,但黄河口尾闾河道的滩地横比降依然远大于河道纵比降,若发生漫滩洪水将极易引起顺堤行洪,会对黄河口堤防安全造成极大威胁. 相似文献