黄河河口延伸与下游淤积关系研究中的问题分析

阐明了黄河河口延伸与下游淤积关系问题的实质,指出了黄河河口延伸与下游淤积关系对时间尺度的依赖性,进而深入探讨了以前研究这一问题所用论据的合理性题。分析结果揭示,那种认为黄河下游淤积由河口延伸控制和河口延伸作用局限于近口河段的说法都缺乏令人信服的证据。     

汉江丹江口水库下游河床演变

丹江口水库建库20多年来,下游河道由堆积性河道变成了冲刷性的河道,河床物质沿程粗化,比降得以调平。水深增加幅度大于河宽,流速并不随着水深增加而加快。深槽、浅滩分布明显化,宽深比不断在减少。整个库下游变化可分为三段:1)近库段,游荡河道向单一限制性曲流转化;2)大支流影响段,河道仍保持着游荡特性;3)下游段,游荡段游荡特性减弱,弯曲段则深蚀作用加强。     

水库修建后黄河下游的河床演变（英文）

Evolution of the river channel downstream of reservoirs is a complex process that is closely related to the operational mode of the reservoirs and the channel boundary conditions. Numerous studies have been carried out on the fluvial processes of downstream reservoirs. However, only a few of them have focused on the relationship between runoff-sediment conditions and channel pattern indicators. Also, the impacts of river training works on fluvial processes are seldom dealt with. In this paper, the evolutionary processes of three sections in the Lower Yellow River, including Tiexie-Yiluo River mouth reach, Huayuankou-Heigangkou reach and Jiahetan-Gaocun reach, were analyzed for variations in the channel boundary line and the mainstream between 1960 and 2015. Channel pattern indicators such as sinuosity, mainstream wandering range and width/depth ratio were analyzed based on field measurements obtained by the Hydrological Department of the Yellow River Conservancy Commission. The effects of river training works on the channel evolution are then described. Since 1960, numerous medium- and large-sized reservoirs have been built on the Yellow River, including Longyangxia Reservoir, Liujiaxia Reservoir and Xiaolangdi Reservoir. These reservoirs impound the runoff from upstream and retain the sediment, which changes the runoff and sediment conditions in the downstream reach. As a consequence, annual runoff and the frequency and peak of flooding have all decreased. As a result, the flow dynamics and their action on the river channel are also reduced, which changes the dynamic state of the river course. The discrimination results obtained using the single parameter discrimination rule and the discrimination equation show that the degree of wandering is weakened in the reaches studied. The variations in the channel pattern indicators show that the sinuosity increases and the wandering range decreases with a reduction in the total annual volume of water. However, the degree of wandering has little relationship to the sediment concentration. In addition, river training works play an important role in controlling the river course. Due to improvements in the river training works, the river course has become more stable under the same runoff and sediment conditions. A new discrimination rule that takes into account the impacts of the river training works is proposed. The discrimination results were found to fit well with the actual river pattern, which shows that the discrimination rule is applicable to the Lower Yellow River. The results show that the runoff and sediment conditions are the most important factors in the evolution of the river course. The river training works have at the same time limited the wandering range of the mainstream and played an important role in the fluvial processes. Both factors combined lead to the stabilization of the river.     

黄河下游河床纵剖面的调整

该文在分析了黄河下游纵剖面及其横断面的长期变化后,提出了河口延伸情况下河道溯源淤积模型,用比降分析,相关分析及河床质粒度分析等方法,探讨了沿程与溯源两种淤积方式对黄河下游纵剖面调整的影响.用最低能量原理和平衡的概念,分析黄河下游平衡纵剖面的形式,说明黄河下游不能达到平衡的原因及现在黄河达到平衡的条件. 经分析作者提出以下论点:黄河下游主要是沿程淤积,溯源淤积居次要地位,其影响范围在艾山以下.横断面形态变化对纵剖面调整影响不大.     

小浪底工程修建对黄河河口淤积影响

本文在整理、分析黄河小浪底工程建成后 ,坝下游来水来沙条件变化的基础上 ,利用若干经验关系式 ,就小浪底工程修建后对黄河河口区清水沟流路的淤积特征和变化趋势进行了研究 ,得到了 :在小浪底水库初期蓄水拦沙运用阶段 ,淤积减少、河口砂嘴发展速度变缓 ;在后期正常调水调沙运用阶段 ,淤积又有所恢复 ,河口砂嘴发展加快的认识。     

水库下游水沙变化与河床演变研究综述

水库建设以满足人类日益增长的水资源及其利用的要求仍是当今世界,特别是发展中国家在水利建设中的一项重要任务。建坝改变了上下游水流边界条件,导致水沙输移变化,同时也触发了河床形态发生相应的调整。自从20 世纪30 年代全球大规模修坝后,关于此课题的研究就层出不穷。本文就此研究主题对国内外研究成果进行梳理与总结,简要综述水库下游水流挟沙变异以及河床形态演变的研究历史与现状,旨在对该领域的研究进展进行全面的归纳与总结。     

黄河下游泥沙淤积的经验统计关系

以黄河下游历年实测水文泥沙资料为基础,运用多元回归分析方法,建立了下游河道淤积量与淤积强度的经验统计关系。揭示了不同粒径组泥沙的来量和它们在全沙中所占的比率对下游河道淤积特征的影响。同时,研究了高含沙洪水及清水基流对下游河道淤积的影响。     

黄河下游河床纵剖面形态及其地文学意义

本文通过河床比降和凹度两个指标,研究黄河下游河床纵剖面形态的自动调整作用,结果发现比降和下凹度多年平均值分别为1.28和1.35,偏离均值为1～2%,变化很小,说明黄河下游河床纵剖面以近于平行抬升的形态调整,标志着河道已进入了老年期发育阶段。对于研究河道发育史和老年期河道的特点,以及在治河上均有重要的理论和现实意义     

从黄河下游的河床演变规律来看河道治理中的调水调沙问题

河流的演变主要决定于流域来水来沙条件及河道边界条件。在多沙河流的治理上,不应仅仅局限于改变河流的边界条件(如加高加固堤防,固定中水河槽等),而应发挥人的主观能动性,同时考虑如何利用上游的水库(或其他工程,如放淤工程),合理调节水沙过     

甬江河床演变及航道治理

本文分析甬江动力、泥沙、边界及河床演变的基本特征,提出甬江航道整治的原则和措施。     

黄河河口拦门沙发育动态

河口拦门沙发育主要取决于河口边界、径流、海洋动力、海面增减水以及河口疏浚等环境要素的相互作用。拦门沙在口门附近呈扇状分布隆起的沙坝,沉积结构为紧密的“铁板沙”.1984-1987年拦门沙自然发育时期,拦门沙长度为7km以上,年平均推进速度1.30km,沙顶高程为-0.1-0.5m;1988-1992年拦门沙人为疏浚发育时期,通过河口疏浚后,拦门沙增长有所减缓,其长度减为4-6km,年平均推进速度降为1.26km,沙顶平均高程下降到-0.7m,相应地减轻了河口地区的防洪压力。     

50年代以来黄河下游河道的萎缩及其原因*

根据黄河下游7个控制断面的深泓高程、平均河底高程、滩槽高差及过水断面面积的历年变化,可以看出黄河下游河道的萎缩过程,大型水利工程的运用及引黄灌溉加速了下游河道的淤积和萎缩。     

黄河口近期环境演变与河口治理

本文分析了近几年来尾闾河道及河口滨海区实测资料，认为尾闾河道河相关系趋向于转好，河口变化造成的溯源冲淤作用影响范围仅有２０几ｋｍ，并且只有在汛期水流强度较大时，才发生溯源调整作用，非汛期淤积严重。由于河口砂咀向海凸出，三角洲前缘形成强流带，加上波浪作用及异重流发育，河口砂咀延伸速度明显减缓。最后，作者对目前河口治理中存在问题的解决提出了建议，尤其指出不应轻易放弃目前良好的河口行水环境。     

黄河中下游水沙变化趋势

本文论述由于黄河上游清水区水资源的优先开发,中上游地区工农业用水的增长,而黄河中游地区的水土保持和支流治理的减沙作用不甚明显,龙羊峡水库投入运用后,汛期进入河口镇的水量大幅度减少,使汛期进入黄河下游的基流减小含沙量增加,高含沙洪水出现的机会增多.面临水少沙多的不利情况,应加强宽浅河道的改造及利用窄深河道输送高含沙水流的研究.     

黄河下游的河性

本文探讨了黄河一般特性的综合关系,讨论了河道演变中均衡与非均衡的问题、滩槽冲淤的利与害和主与从的问题,同时讨论了河道冲淤演变特性、与水沙条件的关系、河槽淤积率和淤积比等。     

黄河下游堤内滩地土地利用的GIS分析

应用航空彩红外土地利用解译图,以ARC INFO为支撑软件,建立了黄河下游河道滩地(花园口至孙口河段)土地利用现状数据库。通过空间拓朴叠加分析,得到不同类型滩地的土地利用状况。并以数字高程模型为基础,本文分析土地利用与河道滩地的空间分布规律。     

三门峡水库影响渭河下游河道横向演变的研究

多沙河流修建水库影响库区河道演变,建库前后河道遵循不同的演变规律,兴建三门峡水库后的15年间赤水河河口至陈村河段发生了7次自然裁弯,三门峡水库改建后20年间却没有发生一次自然裁弯,这是一个非常有趣的现象。文中利用渭河下游河道的实测资料,对比兴建三门峡水库前后以及三门峡改建前后渭河下游河道的横向演变,得到如下几点认识:(1)侵蚀基准面的变化是引起渭河下游河道横向摆动的主要因素;(2)洪水比降变平,相应河道弯曲系数变大,河道由稳定型向摆动型发展;洪水比降变陡,相应河道弯曲系数变小,河道由摆动型向稳定型发展;(3)滩地的泥沙组成代表河岸的可动性。河岸可动性增大,河道由稳定型向摆动型发展,河岸可动性变小,河道由摆动型向稳定型发展;(4)河道断面形态的调整是对基准面变化和来水来沙变化的复杂响应过程;(5)来水来沙影响渭河下游河道横向演变。     

SEDIMENT LOAD AND STORAGE IN THE LOWER YELLOW RIVER DURING THE LATE HOLOCENE

The Yellow River is one of the largest riverine sediment routing system in the world. Like many other rivers, the sediment load of the Yellow River can not be regarded as constant in its long history due to changes in climate and human activities. This study determined sediment storage on the floodplains of the lower Yellow River in five historical periods after the year 602 bc mainly based on data of 93 boreholes, 182 radiocarbon dates in the Huang‐Huai‐Hai Plain and maps of historical changes of the lower Yellow River channel. Furthermore, the mean annual sediment outputs from the upper and middle reaches of the Yellow River were calculated in the five periods through investigating the sediment delivery ratio of the lower Yellow River under different conditions of artificial levees. Our findings suggest that the sediment output from the upper and middle Yellow River increased slowly before the year around 1128, but was lower than half of the current value on average. It has been in the past about 1000 years that the sediment output from the upper and middle Yellow River escalated. The Loess Plateau is the principal sediment source of the Yellow River. The comparison of historical changes in sediment load of the lower Yellow River with those in the natural conditions and in human activities on the plateau reveals that the changes in sediment yield from the plateau could be attributed mainly to the variations of population, cultivating area, and climate changes on the plateau.