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1.
黄河内蒙古河段冲淤演变及其影响因素 总被引：6，自引：1，他引：5
冲淤平衡的河流具有调整河床变形使之趋向不变形的特性,这种特性必然反映在河床横断面冲淤演变的趋势之中。据此,采用横断面冲淤指标跟踪计算法生成黄河上游巴彦高勒、三湖河口站1976-2006 年的横断面冲淤演变时间序列,对该长期序列的趋势变化和突变特点进行分析后发现：内蒙古河床演变明显存在3 个阶段,即演变相对稳定阶段、河床快速萎缩变形阶段和新的相对稳定阶段,以及孔兑来沙大的年份是横断面冲淤面积趋势改变的时间。大型水库修建后,孔兑来沙对河道横断面冲淤趋势变化的影响更加显著,表明近年来大洪水缺失和孔兑来沙的共同作用是导致河床萎缩的重要根源。90 年代中后期横断面冲淤演变再次发生突变之后,内蒙河段进入到一个新的相对稳定期,河床边界条件已经和来水来沙条件相适应,因此在新的稳定条件下,如何治理内蒙河道的淤积萎缩值得探讨。 相似文献
2.
黄河小北干流汛期和非汛期冲淤过程模拟 总被引：1，自引：1，他引：0
滞后性是河流系统自动调整的重要特征之一。根据河道演变的滞后响应机制,在考虑上游来水来沙和下游侵蚀基准面（潼关高程）共同影响的基础上,建立了能够模拟河道汛期和非汛期冲淤过程的滞后响应模型,并采用黄河小北干流1960-2015年的冲淤资料进行参数率定（1960-2001年）和模型验证（2002-2015年）。结果表明该模型能较好地模拟小北干流汛期和非汛期的冲淤过程。汛期和非汛期累计冲淤量的模拟效果优于单个冲淤量;累计冲淤量和单个冲淤量的模拟效果汛期要优于非汛期。三门峡水库修建后,1960-2015年间小北干流汛期和非汛期的冲淤过程表现出时段差异。根据建立的滞后响应模型,本文分析了来水来沙和潼关高程对小北干流汛期和非汛期各个特征时段冲淤的贡献率,汛期和非汛期的第一时段（1960-1970年,1960-1968年）主要受到潼关高程的影响,但是后续时段主要受到来水来沙的影响。 相似文献
3.
近30 年来长江口岸滩沉积物与地貌演变特征 总被引：4，自引：2，他引：2
通过对长江口潮间带宽度、表层和浅地层柱状样沉积物、典型水下岸坡剖面的现场测量,以及对潮间带宽度及水下岸坡剖面的多幅历史海图分析,研究近30 年长江口岸滩演变特征及岸滩演变的主要原因。结果表明:(1) 岸滩沉积物整体上呈“北细南粗”的变化特征,横沙东滩北岸、长江和东海大桥下等主要大型工程附近潮间带柱状样粒序向上显著变粗;(2) 长江口部分潮间带宽度减少90%以上;水下岸坡由1980 年的“S”形向凹形、斜坡形等侵蚀型形态转变,岸坡明显变陡,侵蚀型岸滩特征凸显;南汇嘴至芦潮港岸段水下岸坡闭合水深1978-2004 年为-8 m,近10 年来滩底发生侵蚀,刷深约1 m;(3) 流域来沙量锐减导致长江口侵蚀型水下岸滩格局的形成;河口大面积围垦、青草沙水库和长江与东海大桥等大型工程建设是造成潮间带大面积损失和局部沉积物粗化的主要原因;沙体变迁是狭长型河槽局部岸滩演变的主要影响因素。 相似文献
4.
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
5.
浙南淤泥质海岸冲淤变化和泥沙运动 总被引：3，自引：1，他引：3
本文研究了浙南北起瓯江口,南至平阳咀淤泥质海岸的冲淤演变过程,指出,岸滩每年以10—20米的速度向海淤涨。为该地区海涂的开发提供了依据。 相似文献
6.
三峡水库蓄水后荆江洲滩变化特征 总被引：4，自引：0，他引：4
目前对三峡水库蓄水后荆江河段的洲滩演变还缺乏完整认识。基于三峡水库蓄水前后枯水期遥感影像,分析了荆江洲滩的冲淤变化与分布及形态演变。结果表明,蓄水后荆江洲滩总面积持续冲刷减小,累计冲刷4.56 km2,大部分发生在蓄水后前6年（冲刷速率0.55 km2/a）。上、下荆江洲滩的冲淤演变存在差异性。上荆江洲滩总面积一直处于冲刷萎缩中,且其强度明显大于下荆江,累计冲刷6.46 km2;下荆江前期（2002-2009年）冲刷、后期（2009-2015年）淤增,累计淤1.90 km2。在冲淤分布上,上荆江凸岸滩持续冲刷萎缩,凹岸滩前期冲刷、后期略有淤增,心滩（洲）前期淤积增长而后期冲刷萎缩;下荆江主要是凸岸滩冲刷,凹岸滩和心滩（洲）有所发展。根据滩体位置活动和冲淤动态性,荆江心滩（洲）演变被划分为8种典型类型。在形态演变上,上荆江以凸岸突出滩体和边滩发育的凹岸滩冲刷显著,形态变化不大。下荆江凸岸滩上游弯侧冲蚀后退、湾顶退缩、下游弯侧淤积伸长,形态趋向低弯扁平化,在高弯曲特定河湾平面形态格局下凸岸冲刷—淤积过程延伸到相邻河湾凹岸,成为下荆江凹岸滩和心滩淤积发展的重要因素,但淤积一般不越过凹岸湾顶。 相似文献
7.
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
8.
《中国地理与资源文摘》2007,(3)
TV1482007032002三角洲前缘岸滩对河流来沙减少响应的敏感性探讨:以长江口门区崇明岛向海侧岸滩为例=Sensibility of delta for-ward coastal response to decrease in riverine sedi ment supply:acase study fromthe seaward coast of the Chongming Island inthe Changjiang 相似文献
9.
杭州湾北岸的侵蚀／淤积波及其形成机制 总被引：8，自引：0，他引：8
杭州湾北岸岸滩冲淤变化频繁,侵蚀作用和淤积作用在时间和空间上交互更迭,形成了侵蚀波和淤积波。本文通过不同年代地形图的对比,结合自然条件的分析,探讨杭州湾北岸岸滩冲淤变化的特征和趋势,揭示该岸段慢／淤积波的形成机制,为杭湾北岩的开发利用和海岸防护提供科学依据。 相似文献
10.
中国河流地貌研究进展——纪念沈玉昌先生100年诞辰 总被引：1，自引：0，他引：1
2016年是中国现代河流地貌研究的开拓者和奠基人沈玉昌先生100年诞辰,本文对中国河流地貌研究进展进行综述,以资纪念。研究涉及4个方面：① 水系发育与河谷地貌演变,包括大江大河水系历史发育和山区河流地貌;② 侵蚀与产沙过程,包括有物理成因基础的侵蚀产沙模型、侵蚀产沙过程的尺度效应、植被对侵蚀的影响及临界现象、坡面细沟发育过程模拟等;③ 河床过程与河型,包括河道冲淤过程、河床演变、河型成因与演变等;④ 河流地貌系统研究,包括流域系统不同子系统的耦合关系、河流地貌系统中的高含沙水流和多营力地貌过程、河流地貌系统对于自然因素变化和人类活动的响应、河流地貌系统中的泥沙灾害和河流地貌系统的实验研究等。50年前沈玉昌先生与钱宁先生提出在地貌学与河流动力学相结合的基础上发展中国河流学科。文中对此方面的进展进行了综述,并提出了需要深化和解决的问题。 相似文献
11.
Modeling the growth limit of the Changjiang Delta 总被引：6，自引：0，他引：6
River deltas grow in response to sediment discharge from the land. It is not clear, however, whether or not there is a limit for such growth. Conceptual geometric models are used in this paper, in association with the principle of mass conservation, in an attempt to answer this question. Preliminary analyses of the Changjiang Delta indicate that delta growth is constrained by a number of factors: the original topography/bathymetry, sediment supply, sediment retention in the estuary, sea-level rise, ground subsidence. The quantity of sediment supply per unit area and the Sediment Retention Index for the subaqueous delta decrease as the delta progrades towards deeper water, resulting in a decreasing rate of growth. The limit of growth is reached when the index approaches zero, i.e. the shoreline reaches the shelf edge. If the combined effect of sea-level rise and ground subsidence is considered together with decrease in the sediment discharge from land, the limit is reached at an earlier stage. For the Changjiang Delta, the model output (using hypothesized Sediment Retention Index estimates) implies that the delta growth will reach its limit in the near future. This will occur sooner if the sediment output of the river is reduced to 60% of its original level, in response to the upstream basin changes. Further knowledge, however, is required of the Retention Index, together with the information on future changes in river input and the character of the sediments in order to improve the accuracy of the simulations. 相似文献
12.
The delta evolution and erosion process of the abandoned Yellow River Delta (AYRD) have been extensively studied. However, the variation of sediment at a large littoral scale along the north coast of Jiangsu is less understood. In this study, the data of surface sediment samples obtained in the littoral area of the Yellow River Delta in 2006 and 2012 is used to study the sediment variability and sediment transport trends by using the geostatistics analysis tool and the grain size trend analysis model. In order to ensure the applicability of the model, the geostatistics method is used to determine the characteristic distance (Dc) with the average range value (Ao) of grain size parameter. Filtering method (removing data that not at a sampling station) is used to improve accuracy of data selection. The results show that sedimentary spatial correlation in Lianyun Port area and southern part of the abandoned Yellow River Delta (AS) is better than that in the northern part of the abandoned Yellow River Delta (AN). Sediment in the area is found to be anisotropy at the northeast-southeast direction. The grain size trend analysis reveals that the sediment trend is towards bayhead and southerly in the Haizhou Bay, southeasterly along the shoreline in the south Lianyun Port, northwesterly in AN and easterly-southeasterly in AS respectively. The investigation of possible relationships between Dc, Ao, sediment transport and delta evolution shows a close link between Dc and Ao of one sediment combination. It is also found that sediment transport trends could reasonably represent the delta evolution to a certain degree. 相似文献
13.
Sediment variability and transport in the littoral area of the abandoned Yellow River Delta,northern Jiangsu 总被引：1，自引：0，他引：1
The delta evolution and erosion process of the abandoned Yellow River Delta (AYRD) have been extensively studied. However, the variation of sediment at a large littoral scale along the north coast of Jiangsu is less understood. In this study, the data of surface sediment samples obtained in the littoral area of the Yellow River Delta in 2006 and 2012 is used to study the sediment variability and sediment transport trends by using the geostatistics analysis tool and the grain size trend analysis model. In order to ensure the applicability of the model, the geostatistics method is used to determine the characteristic distance (D c) with the average range value (Ao) of grain size parameter. Filtering method (removing data that not at a sampling station) is used to improve accuracy of data selection. The results show that sedimentary spatial correlation in Lianyun Port area and southern part of the abandoned Yellow River Delta (AS) is better than that in the northern part of the abandoned Yellow River Delta (AN). Sediment in the area is found to be anisotropy at the northeast-southeast direction. The grain size trend analysis reveals that the sediment trend is towards bayhead and southerly in the Haizhou Bay, southeasterly along the shoreline in the south Lianyun Port, northwesterly in AN and easterly-southeasterly in AS respectively. The investigation of possible relationships between D c, Ao, sediment transport and delta evolution shows a close link between D c and Ao of one sediment combination. It is also found that sediment transport trends could reasonably represent the delta evolution to a certain degree. 相似文献
14.
都市圈旅游空间结构演变研究——以长三角都市圈为例 总被引：5，自引：2，他引：3
旅游空间结构演变研究,对优化都市圈旅游空间结构、促进都市圈整体旅游地形成和发挥都市圈旅游空间效应与功能有重要意义。以旅游人数和旅游收入为指标,利用赫芬达尔指数和位序—规模模型进行分析,并结合长三角都市圈旅游发展实际考察其旅游空间结构演变态势。结果表明,长三角都市圈旅游者和旅游收入空间分布趋向分散,各城市旅游发展相对差异不断缩小,其旅游发展趋向均衡化。长三角都市圈旅游发展实际也显示,其旅游空间结构呈现多中心、网络化和一体化特点。从长期来看,长三角都市圈旅游空间结构演变趋向高水平均衡。借鉴空间相互作用理论,认为以可达性、互补性和替代性为必要条件,以集聚和扩散作用为主要形式,以资金、技术、人员、信息和经验等的流动为主要内容,各城市旅游空间相互作用推动了都市圈旅游空间结构不断由低水平均衡向高水平均衡演变。旅游企业扩张和旅游客流流动带动了旅游资金、技术、人员、信息和经验等的集聚和扩散,推动了都市圈旅游空间结构演变。 相似文献
15.
Seasonal distributions of suspended matter and their sedimentary effect on the Changjiang Estuary mud area of the East China Sea were discussed, based on three cruise data of total suspended matter, temperature and salinity collected from the Changjiang Estuary and its adjacent area in summer and winter. The results show that the basic pattern of distributions of suspended matter in the study area is almost the same in winter and in summer. Sediments from Changjiang (Yangtze River) to the sea are chiefly trapped to the west of 123o15'E due to a strong obstruction of the Taiwan Warm Current. This suggests that these sediments are mainly transported and deposited in the inner shelf. The sediment supply, Taiwan Warm Current, and Zhejiang Coastal Current show a strong seasonal variation, which results in a strong seasonal variation of the sedimentary effect on this mud area. This mud area is a "sink" of the Changjiang's sediment discharge to the sea and its sedimentation is stronger in summer and weaker in winter. 相似文献
16.
长江口泥质区的季节性沉积效应 总被引：1，自引：0，他引：1
1IntroductionThe continental shelf of the East China Sea (ECS) is one of the widest shelves in the world. There are several mud areas distributing like patches on a background of widespread coarser ambient sediments of silt and sand on the continental shelf of the ECS. The coastal mud area can be divided into two parts, namely, the Changjiang Estuary mud area (CEMA) in the north and Zhejiang coastal mud area in the south. Between these two parts there is a silt area (Figure 1). The CE… 相似文献
17.
黄河三角洲岸线及现行河口区水下地形演变 总被引：2，自引：0，他引：2
根据实测的岸线和水深数据,利用Surfer 和Mapinfo 等软件进行数据处理,结合不同阶段利津站输沙量,分析了黄河三角洲岸线及现行河口区水下地形演变。结果表明:1953-2000年,68%左右的入海泥沙淤积在口门和滨海区。由于入海流路变迁,不同岸段的岸线变化具有各自的特征。刁口河流路以西岸线基本稳定;刁口河流路以东—孤东油田以北岸线经历先淤后冲,属于强侵蚀岸段,但在防潮大堤的保护下得到人为控制下的稳定;清水沟流路形成的岸线整体向海淤进,但清8 出汊后,清水沟老河口沙嘴南侧出现侵蚀。1976-1996 年,现行河口(清水沟流路) 水下地形总体上表现为淤积,顶坡段变缓,前坡段变陡。1996-2005 年,清水沟老河口水下地形顶坡段和前坡段发生侵蚀,底坡段呈现淤积;出汊新河口水下地形继续淤积,但程度和范围都比1976-1996 年的小。孤东油田近岸侵蚀加剧。 相似文献
18.
Knowledge of the sediment flux derived from different sources is critical for interpreting the sedimentary records associated with large river sedimentary systems. For the Changjiang River system, previous studies hardly focused on the sediment load from the adjacent Zhoushan Archipelago (ZA). Based on four prediction models, aiming to improve the understanding of the sediment load from the ZA during the Holocene, we show that the predicted sediment flux of the ZA ranges from ~0.7 to 26.5 Mt·yr-1, with an average value of 10.7 Mt·yr-1, and the islands with a relatively large area or high relief contribute greatly to the total flux. This sediment load is an order of magnitude lower than that of the Changjiang River, but it is similar to those of the local small rivers. Located in the core area of the southward dispersal path of the Changjiang River plume, the ZA also influences the sediment transport into Hangzhou Bay and over the Zhejiang-Fujian coastal seas. On the Holocene temporal scale, e.g., for the period from 6 ka BP to 2 ka BP, the sediments discharged from the ZA had a considerable effect on the shelf sedimentary system. This study provides evidence for an important role an archipelago can play in terms of sediment supply and transport in coastal and inner continental shelf regions. 相似文献
19.
黄河三角洲造陆过程中的陆域水沙临界条件研究 总被引：26，自引：5，他引：26
黄河三角洲发育是河口区河流动力及陆域物质通量与海洋动力及海域物质通量相互作用的产物 ,三角洲造陆速率取决于上述两方面的对比关系。当上述两方面处于平衡时 ,三角洲造陆处于临界状态 ,即净造陆速率为零 ,与之相联系的入海泥沙量和径流量可视为黄河三角洲造陆过程的临界水沙条件。运用经验统计方法估算出 :当入海年沙量Qs为 2 78亿t/a、入海年水量Qw为 76 7亿m3时 ,或者当关系式 3 1934Qs+ 0 0 85 6Qw=17 94得到满足时 ,黄河三角洲造陆过程处于临界平衡状态。在黄河流域的环境管理中 ,应将上述两项临界值作为约束条件。黄河流域生态用水量的内涵应予以扩展 ,维持三角洲造陆平衡所必须的入海径流量 ,应作为黄河流域的生态用水量。 相似文献