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1.
40年来长江九江河段河道演变及其趋势预测 总被引：8，自引：4，他引：4
利用地理信息系统(GIS)与数字高程模型(DEM)技术定量模拟40年来九江河段冲淤演变过程,结果表明: 1963~1972年总体表现为淤积,淤积量为6.505 hm3,平均淤积速率为0.65 hm3/a。1972~2002年总体表现为冲刷,冲刷量为20.720 hm3,平均年冲刷率为1.036 hm3/a。1963~2002年九江河床总体表现为冲刷,冲刷量为14.977 hm3。2003年与1963年比较,河床淤积区域主要分布在九江河道上段近南岸区域,中下段河道的中间区域;冲刷区域主要分布在九江河道上段的中间及近北岸区域,中下段河道两岸的近岸区域。中下段南岸的不断刷深和南偏对九江的防洪带来更大的压力。 相似文献
2.
三峡水库运行下洞庭湖盆冲淤过程响应与水沙调控阈值 总被引：4，自引：0，他引：4
以1951-2011 年洞庭湖区及荆江段干流主要控制站实测径流输沙量资料为依据,分析三峡水库不同蓄水阶段及不同调度方式下洞庭湖盆冲/淤响应,并提出上游来水来沙调控阈值。结果表明：① 荆南三（四）口流量与枝城站流量、荆南三（四）口输沙率存在极显著正相关（p < 0.0001）,决定系数r2分别为0.859 及0.895。② 与三峡水库蓄水运用前（1999-2002）相比,一、二期蓄水阶段及全面试验性蓄水阶段（2008.10-2011.12）洞庭湖盆年均冲淤量由+4796.4×104 t 依次递减为+684.1×104 t、+449.8×104 t 及-559.6×104 t,湖盆冲淤率由+70.25%分别降至+31.13%、+23.56%及-42.64%。③ 预泄调度及蓄水调度期,湖盆泥沙均由以淤积为主转变为以冲刷为主,防洪补偿调度期湖盆泥沙表现为淤积,而在补水调度运用期则表现为冲刷。④ 洞庭湖盆处于冲/淤临界平衡状态时的荆南三口平均流量、输沙率及含沙量分别为970.81 m3/s、466.82 kg/s 及0.481 kg/m3。并认为,为增强湖泊调蓄功能,必须进一步优化三峡水库调度方式,合理调控下泄水沙量。 相似文献
3.
不同流路时期黄河下游河道的冲淤变化过程 总被引：4，自引：2，他引：2
运用统计学方法对1950-2007年的水沙数据以及不同流路各水文站同流量(3000m3/s)水位变化进行了分析,结果表明:黄河下游河道表现出淤积-冲刷交替出现的变化过程,当进入下游的含沙量为18.6kg/m3时,河道冲淤表现为动态平衡。艾山以下河道的冲淤变化过程除受水沙条件控制外,还受到流路变迁的影响。流路变迁初期河道发生溯源冲刷作用,中后期河道发生溯源淤积作用。各站同流量水位变化,神仙沟流路主要为下降,河道以冲刷为主;刁口河流路主要为升高,河道以淤积为主;清水沟流路有升有降,河道冲淤互有,总体表现为淤积。流路变迁对河道横断面形态的影响主要在利津以下。 相似文献
4.
对黄河内蒙古段河道大断面进行了连续4 a的测量,分析了断面泥沙冲淤与形态调整的变化过程;通过对河床形态指标变化与水沙条件的相关分析,揭示了河床调整主要的影响因素。结果显示：近4 a内不存在河槽萎缩的现象,整个河段河道存在总的冲刷降低的趋势,继承了自2004年以来该段河道以深度加大为主,河槽逐渐缓慢扩大的变化方向。整个河段平均从2011年汛后至2014年汛后,全断面冲刷了64 m2,河槽河底降低了0.16 m,河槽断面面积增加了4.4%,平均深度增加了4.9%,河槽宽度只增加了0.88%,河槽宽深比减小了4.8%。河槽冲刷和形态调整主要发生在2011年汛后至2012年汛后期间,与2012年较大的洪峰有关。分析河槽冲淤和断面形态变化与水沙条件的关系,结果显示滩唇高度、河槽过水面积、平均深度及宽深比变率与流量大小关系密切。滩唇高度、河槽过水面积、平均深度随着流量的增大而增加,宽深比随着流量的增大而减小。相反,河床断面面积和主槽宽度的变化与水沙条件的关系不显著。除了滩唇高度与平均含沙量有关外,平均含沙量和来沙系数与河床冲淤以及河槽形态变化之间关系都不显著。揭示出近年来内蒙河道主槽以垂向冲淤为主,并且流量变化控制着河槽冲淤与形态调整过程。 相似文献
5.
基于实际粮食产量与抛荒耕地种植粮食作物条件下粮食总产量关系的分析方法有助于促进耕地红线制度改进。依据全国粮食总产量、种植面积与耕地面积数据,构造2016-2033 年粮食产量与耕地面积红线耦合的基本、法定、过渡、新型与理想耦合红线标准;分析阶段性耦合与可持续耦合两种升级路径。研究表明：2001-2015 年,全国耕地面积与粮食产量耦合不足。据此,提出以新增建设用地指标与抛荒治理面积挂钩的政策建议;在抛荒比例11.12%的条件下,新增单位面积建设用地,治理28.85 倍抛荒耕地;2017、2021、2025、2029、2033 年分别实现有效利用1.200×108 hm2、1.243×108 hm2、1.279×108 hm2、1.314×108 hm2、1.349×108 hm2 耕地,粮食总产量分别比基期增加4.838×106、2.4190×107、4.354 2×107、5.321 8×107、8.824 6×107 t;红线耦合系数分别达到0.882 471、0.909 740、0.937 008、0.950 643与1;有效利用耕地增加12.5%,粮食总产量提升14.2%。 相似文献
6.
长江干流河道对流域输沙的调节作用 总被引：1，自引：0，他引：1
利用长江干流和主要支流上测站1956~2004年的输沙量资料,对干流未测区域的来沙进行了估计。根据泥沙平衡 (Sediment budget) 概念,对长江干流河道的冲淤对来水来沙的响应以及对入海泥沙的影响进行研究发现,长江干流屏山至大通河道平均淤积速率为88.58×106 t/a,河道淤积占总的来沙量及大通站输沙量比例分别为14%与21%。由于河道淤积,大通站输沙量减少了17.5%。总体来说上游淤积较轻,宜昌至汉口区间淤积严重,汉口至大通区间为微冲。长江干流的河道冲淤与流域总的来沙具有显著的相关关系,但各段河道的冲淤对流域来沙的响应各不一样。上游的冲淤与流域的径流量和来沙量均没有很好的相关性,宜昌-汉口段河道冲淤的变化与宜昌站的来沙具有显著的相关性;影响汉口-大通间河道的冲淤变化的主要因素是流域的来水量,河道的冲淤与大通站径流量的存在显著的负相关关系。三峡水库蓄水后整个长江干流的冲淤形势发生了根本的变化。三峡水库的蓄水运用有效地减轻了洞庭湖的泥沙淤积,同时也降低了洞庭湖的对长江干流泥沙的调节作用;长江上游干流河道淤积增强,中下游河道出现冲刷,但不同的河段表现不一;中下游河道冲刷量小于预测值,三峡水库的蓄水运用直接导致了长江入海泥沙的减少。 相似文献
7.
近10 年来长江口水下三角洲的冲淤变化 ——-兼论三峡工程蓄水的影响 总被引：4，自引：0，他引：4
根据对近10 年来长江入海泥沙量和河口冲淤的对比分析, 探讨水下三角洲冲淤对长江入海泥沙锐减以及三峡工程运行的响应。结果表明: (1) 三峡水库蓄水导致长江入海泥沙减少1×108 t/a 量级; (2) 1995-2000 年、2000-2004 年和2004-2005 年研究区淤积(冲刷) 面积分别占75.5% (24.5%)、30.5% (69.5%) 和14% (86%), 垂向冲淤速率(负为冲刷) 分别为6.4 cm/a、-3.8 cm/a 和-21 cm/a。(3) 由于地形和水动力的变化以及工程的影响, 研究区内冲淤对河流来沙减少的响应存在显著空间差异。结论包括: 三峡水库蓄水加剧了长江入海泥沙的减少; 入海泥沙的锐减是水下三角洲从淤积为主向侵蚀为主转变的主要原因。随着水库拦沙能力的增强等流域人类活动的影响, 长江入海泥沙将进一步下降, 河口口门区的冲刷可能加剧, 值得有关部门重视。 相似文献
8.
重庆主城区河段河道泥沙冲淤事关防洪、航运及码头作业等,是三峡水库泥沙问题的重点内容之一。本文依据原型观测资料,以三峡水库175 m试验性蓄水前后河段的泥沙冲淤规律为基础,结合河床组成分析和一维数学模型,计算提出河段悬移质泥沙走沙基本条件,并应用于减淤调度实践中。结果表明：① 三峡水库175 m试验性蓄水后至2012年重庆主城区河段河床冲刷强度下降,主走沙期推迟至汛前消落期,2013年后上游来沙减少使得河床冲刷强度再次增大;② 当寸滩站流量大于4000 m 3/s、坝前水位低于167 m时,河段开始走沙;当寸滩站流量增大至超过5000 m 3/s、坝前水位下降至163 m时,河段走沙能力增强;加大水库自163 m水位的消落速度,能够避免库尾河段产生累积性淤积。 相似文献
9.
塔里木河流域水资源变化的特点与趋势 总被引：30，自引：1，他引：29
通过时间序列分析了塔里木河流域山区1961~2002年的降水和温度变化, 源流干流水分的消耗, 并对这些指标进行了KENDALL秩次相关检验。结果显示: 塔里木河源流山区降水和温度均有增加,但是降水增加的趋势在?琢 = 0.05水平上不显著, 温度升高的趋势显著; 塔里木河流域几个源流水量增加, 特别是在1994~2002年,年平均径流量比多年平均增加了25.163×108 m3/a, 而上游三源流补给干流水量只增加0.9985×108 m3/a, 塔里木河干流沿程各站的径流量呈现显著的线性递减趋势, 表明连续十年的丰水期并没有改变干流生态环境恶化的局面; 如果三源流来水以正常年份计算 (1957~2003年平均来水量), 塔里木河干流来水量每年只有22.57×108 m3, 那样塔里木河流域的生态安全将更令人担忧。 相似文献
10.
2002年开始的黄河调水调沙改变了进入黄河口的水沙条件,必然引起尾闾河道地貌的显著调整。根据黄河尾闾河道利津以下的断面实测高程数据,建立基于正交曲线网格的河道DEM,结合河床形态与水沙条件变化,综合研究黄河尾闾河道冲淤的时空演变及其影响因素。结果表明,调水调沙以来尾闾河道冲刷明显,2002—2017年累计冲刷6240万m 3,根据冲淤速率可以分为3个阶段：快速冲刷阶段（2002—2005年）冲刷速率为1443万m 3/a;冲刷减慢阶段（2006—2014年）冲刷速率为139万m 3/a;以及淤积阶段（2015—2017年）,淤积速率为263万m 3/a。其中,调水调沙初始4年尾闾河道的冲刷量占总冲刷量的80%,2006年以后冲刷强度逐渐减弱,甚至转为淤积。从季节上看,主要表现为汛期冲刷,非汛期淤积;从空间上看,越往口门方向,冲刷强度越小。调水调沙改变了入海水沙的年内分配,造成了尾闾河道的持续冲刷,入海流路也发生多次调整。但经过多年冲刷,河床整体下切,加上河口淤积延伸影响,调水调沙对尾闾河道的冲刷效率在持续降低。受河口海域淤积影响,近口门段在经历冲刷后转为淤积,河道纵比降减缓,增加了尾闾的不稳定性。 相似文献
11.
长江中游马口-田家镇河段40年来河道演变 总被引：2，自引：1，他引：1
Quantitative analysis was performed on the filling-scouring process for the river reach within Makou and Tianjiazhen, the middle Yangtze River with the help of GIS and DEM techniques. The research results indicate that the river reach between Makou and Tianjiazhen was dominated by the scouring process, and the magnitude of scouring is increasing over time. The intensity of scouring process is more in the deep and narrower river reach than shallower and wider ones. The river reach in the Makou and Tianjiazhen river knot is in fre-quent scouring and filling process, however the river reach upper to the Makou and lower to the Tianjiazhen river knot is in moderate scouring and filling process. The river reach just upstream or downstream to the river knot (e.g. Makou and Tianjiazhen river knot in this research) is dominated by filling process and the river reach in the river knot is dominated by the scouring process. Research results indicate no changes in the boundary of the river but the scouring and the filling magnitude in specific river channel is strong. The filling and the scouring process of the study river reach is greatly impacted by the sediments and water from the upstream of the study river reach. The construction of the Three Gorges Dam just upstream to Yichang will cause further decrease of the release of the sediment load to the middle and the lower Yangtze River basin, which will further intensify the scouring process of the river channel in the study river reach. 相似文献
12.
Quantitative analysis was performed on the filling-scouring process for the river reach within Makou and Tianjiazhen, the middle Yangtze River with the help of GIS and DEM techniques. The research results indicate that the river reach between Makou and Tianjiaz-hen was dominated by the scouring process, and the magnitude of scouring is increasing over time. The intensity of scouring process is more in the deep and narrower river reach than shallower and wider ones. The river reach in the Makou and Tianjiazhen river knot is in fre-quent scouring and filling process, however the river reach upper to the Makou and lower to the Tianjiazhen river knot is in moderate scouring and filling process. The river reach just upstream or downstream to the river knot (e.g. Makou and Tianjiazhen river knot in this re-search) is dominated by filling process and the river reach in the river knot is dominated by the scouring process. Research results indicate no changes in the boundary of the river but the scouring and the filling magnitude in specific river channel is strong. The filling and the scouring process of the study river reach is greatly impacted by the sediments and water from the upstream of the study river reach. The construction of the Three Gorges Dam just up-stream to Yichang will cause further decrease of the release of the sediment load to the mid-dle and the lower Yangtze River basin, which will further intensify the scouring process of the river channel in the study river reach. 相似文献
13.
Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler (ADCP) instrument, we analyzed shapes of river cross sections of the middle Yangtze River basin (mainly focusing on Makou and Tianjiazhen river reach). Hydrodynamic properties of river channels were also discussed. The research results indicate that nonlinear relationships can be identified between river-width/river-depth ratio (W/D ratio), sizes of cross section and mean flow velocity. Positive relations are detected between W/D ratio and mean flow velocity when W/D<1; and negative relations are observed when W/D>1. Adverse relationships can be obtained between W/D ratio and cross-section area. Geomorphologic and geologic survey indicates different components of river banks in the wider and narrower river reaches respectively. These may be the main driving factors causing unique hydrological properties of river channels in the middle Yangtze River basin. Narrower river cross sections tend to raise water level in the upstream river reach near narrower river channel, giving rise to backwater effects. River knots can cause serious backwater effects, which is harmful for flood mitigation. However river knots will also stabilize river channel and this will be beneficial for river channel management. The results of this paper may be helpful for flood mitigation and river channel management in the middle Yangtze River basin. 相似文献
14.
Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler (ADCP) instrument, we analyzed
shapes of river cross sections of the middle Yangtze River basin (mainly focusing on Makou and Tianjiazhen river reach). Hydrodynamic
properties of river channels were also discussed. The research results indicate that nonlinear relationships can be identified
between river-width/river-depth ratio (W/D ratio), sizes of cross section and mean flow velocity. Positive relations are detected
between W/D ratio and mean flow velocity when W/D<1; and negative relations are observed when W/D>1. Adverse relationships
can be obtained between W/D ratio and cross-section area. Geomorphologic and geologic survey indicates different components
of river banks in the wider and narrower river reaches respectively. These may be the main driving factors causing unique
hydrological properties of river channels in the middle Yangtze River basin. Narrower river cross sections tend to raise water
level in the upstream river reach near narrower river channel, giving rise to backwater effects. River knots can cause serious
backwater effects, which is harmful for flood mitigation. However river knots will also stabilize river channel and this will
be beneficial for river channel management. The results of this paper may be helpful for flood mitigation and river channel
management in the middle Yangtze River basin.
Foundation: National Natural Science Foundation of China, No.40701015; Key Project of National Natural Science Foundation of China, No.40730635
Author: Zhang Qiang (1974–), Ph.D and Associate Professor, specialized in natural hazards and climatic changes, hydrologic statistics,
floods and fluvial geomorphology. 相似文献
15.
Channel morphology and its impact on flood passage, the Tianjiazhen reach of the middle Yangtze River 总被引：1，自引：0，他引：1
The Tianjiazhen reach of the middle Yangtze is about 8 km long, and characterized by a narrow river width of 650 m and local water depth of > 90 m in deep inner troughs, of which about 60 m is below the mean sea level. The troughs in the channel of such a large river are associated with regional tectonics and local lithology. The channel configuration plays a critical role in modifying the height and duration of river floods and erosion of the riverbed. The formation of the troughs in the bed of the Yangtze is considered to be controlled by sets of NW–SE-oriented neotectonic fault zones, in which some segments consist of highly folded thick Triassic limestone crossed by the Yangtze River. Several limestone hills, currently located next to the river channel, serve as nodes that create large vortices in the river, thereby accelerating downcutting on the riverbed composed of limestone highly susceptible to physical corrosion and chemical dissolution. Hydrological records indicate that the nodal hills and channel configuration at Tianjiazhen do not impact on normal flow discharges but discharges > 50,000 m3s− 1 are slowed down for 2–3 days. Catastrophic floods are held up for even longer periods. These inevitably result in elevated flood stages upstream of prolonged duration, affecting large cities such as Wuhan and a very large number of people. 相似文献
16.
长江中游田家镇深槽的特征及其泄洪影响 总被引：4，自引：1，他引：3
长江中游田家镇附近江面最狭处仅650 m, 江底最深处低于黄海基准面以下-90 m, 是长江干流河床突出的最低所在, 距离长江口900 km。通过实地地质地貌调查揭示田家镇深槽形成及其对洪水的渲泄有何影响。 根据地质、水文、地形和直接考察资料, 卡口深槽段长8 km, 系长江自NW-SE斜切过一排强烈褶曲的三叠系厚层石灰岩山地而成, 3个临江石灰岩小山所成矶头导致江流方向变化与流速加速, 以至形成多处涡流, 向江底侵蚀, 而褶皱的石灰岩抗拒侵蚀、溶蚀能力很低, 因而导致远低于海平面深槽的形成, 估计卡口深槽是从中更新世红色风化壳发育的和缓起伏的地面上叠置下来, 已有以10万年年计的长远历史。近数十年多次实测资料比较, 侵蚀淤积有小量变化, 但河床基本稳定。对正常的中、枯水位江流运行没有影响, 但对超过50 000~60 000 m3/s洪水的排泄则有明显的壅阻作用。 相似文献
17.
长江中下游阻隔性河段作用机理 总被引：1，自引：0，他引：1
阻隔性河段能够阻隔上游河势调整向下游的传递,对稳定河势起到关键性作用。本文以长江中下游34个单一河段为研究对象,在系统总结长江中下游河道演变规律的基础上,归纳出阻隔性河段控制要素包括：单一微弯的河道平面形态、河段中上部无挑流节点;河相系数小于4;河道纵比降大于1.2?;凹岸黏粒含量高于9.5%;床沙中值粒径大于0.158 mm等。从Navier-Stokes方程出发,推导出河湾水流动力轴线弯曲半径的表达式,进而分析了各控制要素对水流动力轴线摆动及阻隔性河段形成的作用。阻隔性河段的判别条件为：不同流量级下水流动力轴线摆动力与河道边界条件约束力的比值始终小于1;阻隔性河段作用机理在于：即便上游河势发生调整,本河段的河道边界始终能约束主流摆动幅度,归顺上游不同河势条件下的主流平面位置,为下游河道提供了相对稳定的入流条件,从而阻隔上游河势调整向下游传递。 相似文献
18.
Xingying You Jinwu Tang Xiaofeng Zhang Weiguo Hou Yunping Yang Zhaohua Sun Zhaohui Weng 《地理学报(英文版)》2017,27(10):1249-1267
Alluvial channel has always adjusted itself to the equilibrium state of sediment transport after it was artificially or naturally disturbed. How to maintain the equilibrium state of sediment transport and keep the river regime stable has always been the concerns of fluvial geomorphologists. The channel in the middle and lower reaches of the Yangtze River is characterized by the staggered distribution of the bifurcated river and the single-thread river. The change of river regime is more violently in the bifurcated river than in the single-thread river. Whether the adjustment of the river regime in the bifurcated river can pass through the single-thread river and propagate to the downstream reaches affects the stabilities of the overall river regime. Studies show that the barrier river reach can block the upstream channel adjustment from propagating to the downstream reaches; therefore, it plays a key role in stabilizing the river regime. This study investigates 34 single-thread river reaches in the middle and lower reaches of the Yangtze River. On the basis of the systematic summarization of the fluvial process of the middle and lower reaches of the Yangtze River, the control factors of barrier river reach are summarized and extracted: the planar morphology of single-thread and meandering; with no flow deflecting node distributed in the upper or middle part of the river reach; the hydraulic geometric coefficient is less than 4; the longitudinal gradient is greater than 12‰, the clay content of the concave bank is greater than 9.5%, and the median diameter of the bed sediment is greater than 0.158 mm. From the Navier-Stokes equation, the calculation formula of the bending radius of flow dynamic axis is deduced, and then the roles of these control factors on restricting the migration of the flow dynamic axis and the formation of the barrier river reach are analyzed. The barrier river reach is considered as such when the ratio of the migration force of the flow dynamic axis to the constraint force of the channel boundary is less than 1 under different flow levels. The mechanism of the barrier river reach is such that even when the upstream river regime adjusts, the channel boundary of this reach can always constrain the migration amplitude of the flow dynamic axis and centralize the planar position of the main stream line under different upstream river regime conditions, providing a relatively stable incoming flow conditions for the downstream reaches, thereby blocking the upstream river regime adjustment from propagating to the downstream reaches. 相似文献
19.
CHAI Yuanfang YANG Yunping DENG Jinyun SUN Zhaohua LI Yitian ZHU Lingling 《地理学报(英文版)》2020,30(10):1633-1648
The operation of large-scale reservoirs have modified water and sediment transport processes, resulting in adjustments to the river topography and water levels. The polynomial fitting method was applied to analyze the variation characteristics of water levels under different water discharge values in the Jingjiang reach of the Yangtze River from 1991–2016. The segregation variable method was used to estimate the contributions of the varied riverbed evaluation, the downstream-controlled water level, and the comprehensive roughness on the altered water level at an identical flow. We find that low water levels in the Jingjiang reach of the Yangtze River from 1991–2016 are characterized by a significant downward trend, which has intensified since 2009. Riverbed scouring has been the dominate factor causing the reduced low water level while increased roughness alleviated this reduction. From 1991–2016, there was first a decrease followed by an increase in the high water level. The variation characteristic in terms of the "high flood discharge at a high water level" before 2003 transformed into a "middle flood discharge at a high water level" since 2009. The increased comprehensive roughness was the main reason for the increased high water level, where river scouring alleviated this rise. For navigation conditions and flood control, intensified riverbed scouring of the sandy reaches downstream from dams enhanced the effects that the downstream water level has on the upstream water level. This has led to an insufficient water depth in the reaches below the dams, which should receive immediate attention. The alteredvariation characteristics of the high water level have also increased the flood pressure in the middle reaches of the Yangtze River. 相似文献
20.
水库运行改变了坝下游水沙输移条件,在河道冲刷的同时,引起水位过程出现适应性调整。本文以长江中游荆江河段为对象,采用多项式拟合法,对比分析1991—2016年间分级流量—水位变化特征,采用基于河流动力学原理的分离变量法,识别河道冲淤、下游控制水位及河床综合糙率等变化对分级流量—水位变化的影响程度。研究表明：1991—2016年间,长江中游荆江河段同流量—枯水位呈下降趋势,2009年以来降幅增大;河道冲刷是引起同流量—枯水位下降的主控因素,河床综合糙率增加抑制了同流量—枯水位下降起到积极作用。1991—2016年间,荆江河段同流量—洪水位经历了先减小后增大的“凹”线型变化,2003年以前洪水特征为“高洪水流量—高水位”,2009年以来逐渐演化为“中大洪水流量—高水位”,同流量—洪水位特性发生转变;河床综合糙率增大是同流量—洪水位抬升的主控因素,河道冲刷抑制了同流量—洪水位的抬升态势。在航道条件及防洪情势上,应重点防控近坝段沙质河段冲刷引起的水位下降溯源传递作用,其洪水流量—水位特性的转变,不利于减缓荆江河段的防洪压力。 相似文献