Formation of Equilibrium Beach Profile of the Abandoned Yellow River Delta Coast in North Jiangsu

The abandoned Yellow River Delta coast is a typical erodible silty and muddy coast in China. The paper analyses the marine dynamic characteristics and the mechanism of beach erosion of this area. Analysis and calculation show that in this sea area wave and tidal current action should be considered. Based on the above analysis, an equilibrium beach profile calculation model is developed, in which the wave-current interaction is considered while sediment supply and sediment re-deposition are neglected. The model consists of four parts: (1) calculation of wave parameters, (2) calculation of velocity due to wave-current interaction at different water depth, (3) calculation of friction velocity and shear stress at different water depths, and (4) calculation of the amount of sediment erosion, erosion intensity and variation of beach profile. Calculated results are in good agreement with observed data. Finally, the evolution tendency is discussed and the equilibrium beach profile of this coast is calculated. B

A flume test on erosion mechanism for an abandoned section of the Huanghe(Yellow)River Delta

The erosion mechanisms of abandoned coastal section are understood detailedly by flume experiment, which play an important role to the offshore engineering facilities. A movable-bed physical model has been used to investigate the coastal erosion of an abandoned section of the Huanghe （Yellow） River Delta. The theory of physical scale models is discussed and a method for constructing the representative seabed section is developed. The results indicate that during the period initially after the abandonment of the delta the entire bed experienced rapid erosion because the seabed was steep and prone to liquefaction that resulted from storm wave action. After this initial period, a balance of erosion and accretion was established, and the beach profllc equilibrated with a point of balance present on the profile. The experimental results indicate that the volume of deposition was about half that of the erosion. Wave action may also induce significant stratal changes through its interaction with the soft seabed. The major morphological features developed in the model delta section were found to be qualitatively comparable with those observed in the prototype. A distorted modeling law that maintains the similarity of the modeled and prototype equilibrium beach profiles is proposed. Experimental results show that the distorted modeling is able to reproduce the beach-face slope in nature, and the model also successfully reproduced three historical evolutionary stages of erosion.

Inversion and Prediction of Consolidation Settlement Characteristics of the Fluvial Sediments Based on Void Ratio Variation in the Northern Modern Yellow River Subaqueous Delta, China

The modern Yellow River delta is formed near the estuary of the Yellow River with the characteristics of short formation time, efficient sedimentation rate and loose structure which make sediments prone to be compacted and consolidate under the geostatic stress and overburden stress. It is one of the key areas with land subsidence disasters in China, bringing a series of safety hazards to production and living. Based on the data of massive surface cores and ten drill holes ranging from 12 to 40 m obtained from the northern modern Yellow River subaqueous delta, the inversion method suitable for the calculation of consolidation settlement characteristics of the modern Yellow River subaqueous delta is discussed, and the consolidation settlement characteristics of the delta sediments are inversed and predicted in this paper. The actual void ratio of the delta sediments at the depth from 3 to 15 m shows a significant power function relationship with the depth, while the void ratio of the sediments below 15 m changes little with depth. The pre-consolidation settlement(from deposition to sampling) of the delta sediments is between 0.91 and 1.96 m, while the consolidation settlement of unit depth is between 9.6 and 14.0 cm m^(-1). The post-consolidation settlement(from sampling to stable) of the subaqueous delta sediments is between 0.65 and 1.56 m in the later stage, and the consolidation settlement of unit depth is between 7.6 and 13.1 cm m^(-1) under the overburden stress. The delta sediments with a buried depth of 3 to 7 m contribute the most to the possible consolidation settlement in the later stage.

Biogenic Sedimentary Structures of the Yellow River Delta in China and Their Composition and Distribution Characters

The biogenic sedimentary structures （i.e., the morphology and trace makers of burrows, tracks, trails and traces made by extant organisms） and their composition and distribution characters in different micro environments and sub environments of the Yellow River delta in China are described. Three ichnocoenosis can be recognized： （1） Steinichnus-like ichnocoenosis, includes F, Y-shaped traces, birds＇ footprints on bedding plane, and Y, U-shaped burrows in intrastratal bedding, produced by Coleoptera （Heteroceridae）, Orthoptera （Gryllotalpidae） and birds. It is majorly found at the delta plain point bar deposits, denoting the fresh water-related terrestrial environments. （2） Steinichnus-Psilonichnus-like ichnocoenosis, consitsis of Steinichnus-like traces on the bedding plane and Psilonichnus-like burrow which a vertical, irregularly J-, Y-, or U-shaped burrows, some of them with bulbous basal cells burrows in the intrastratal bedding, created by Coleoptera （Heteroceridae）, Orthoptera （Gryllotalpidae） and crabs. It is observed in the delta plain abandoned distributary channels, and the delta front tidal creek and subaquous distributary channels, indicating the brackish water environment. （3） Palaeophycus-like ichnocoenosis, includes the round entrance burrows or with craters-shaped loop-protrusionsand and the parallel forked trails on the bedding plane, and the U, J or vertical shaped feeding burrows are in the intrastratal bedding, majorly produced by the clam （bivalve molluscs）, gastropods and Nereis. It is present in the subaqueous interdistributary bay, reflecting the intertidal related environment.

Estimation on wetland loss and its restoration potential in Modern Yellow River Delta,Shandong Province of China

Wetland is one of the most important ecosystems with varied functions and structures,and its loss has been a major issue.Wetland loss in Modem Yellow River Delta(MYRD) becomes a serious environmental problem,so its restoration attracts a great deal of attention from academia and governments.This article proposes a GIS-based multi-criteria comprehensive evaluation methodology for potential estimation of wetland restoration,using MYRD as an example.The model uses four kinds of data(hydrology,terrain,soil,and land use) and could be adapted by planners for use in identifying the suitability of locations as wetland mitigation sites at any site or region.In the application of the model in the MYRD,the research developed a lost wetland distributed map taking the better wetland situation of 1995 as the reference,and elevated the overall distribution trends of wetland restoration potential based on wetland polygon.The results indicated that the total area of wetland loss from 1995 to 2014 was 568.12 km^2,which includes 188.83 km^2 natural wetland and 21.80 km^2 artificial wetland,respectively.The areas of lost wetland with low,middle,and high resilience ability are 126.82 km^2,259.92 km^2,and 119.59 km^2,occupying 25.05%,51.33%,and 23.62%,respectively.The high-restoration-potential wetland included98.47 km^2 of natural wetland and 21.12 km^2 of artificial wetland,which are mainly bush,reed,and ponds.The highrestoration-potential wetland is mainly distributed in the vicinity of Gudong oil field,the Yellow River Delta protected areas,and the eastern sides of Kenli county and Dongying city.

Evolution of Modern Yellow River Delta Coast

This paper deals with the development and evolution of modern Yellow River delta and the erosion or deposition rates of its different sections. In June, 1996, Yellow Rivers terminal course was artificially turned eastwards to empty into the sea and then the 11th lobe of the modern Yellow River delta began to form. This course change may mark the beginning of the 3rd subdelta formation. As a result of that, the Yellow River delta advances towards east by north with the 1st, 2nd and 3rd subdeltas arranged in succession. Coast zone in the deltaic area is divided into 7 different sections according to their different erosion or deposition rates: the relatively stable section from Dakou River to Shunjiang Stream, the weakly retreating section from Shunjiang Stream to the Tiaohe River mouth, the strongly retreating section from the Tiaohe River mouth to the station 106, the artificially stable section due to stone dam protection from the station 106 to Gudong Oilfield, the strong deposition section from Gudong Oilfield to Dawenliu Haipu, the weakly deposition section from Dawenliu Haipu to the Zimai Stream mouth, and the stable section from the Zimai Stream mouth to the Jiaolai River mouth. It is predicted that the erosion and deposition situations of the sections will nearly remain the same in 10 years, but the retreating and silting-up rates will tend to become slower gradually. Human activities have an evident influence on the changes of the coastline.

Sediment variability and transport in the littoral area of the abandoned Yellow River Delta, northern Jiangsu

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 （De） 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 direc- tion. 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 Do, Ao, sediment transport and delta evolution shows a close link between Do and Ao of one sediment combination. It is also found that sediment transport trends could reasonably represent the delta evolution to a certain degree.

Effects of Coastline Changes on Tide System of Yellow Sea off Jiangsu Coast,China

On the basis of historical documents, this paper studies the evolutionary processes of the Jiangsu coast and re-estahhshes the positions of the shoreline in different periods. The East China Sea and the Yellow Sea mathematical models are applied to simulate and analyze the large-scale tidal waves changes under the influence of the coastal change in Jiangsu since 1855 when the Yellow River changed its lower course into the Bohai Sea. Results from this study can be summa- rized in the following aspects： （1） the coastline change strongly affects tidal waves in the region. Generally, the tidal amphtude decreases when the coastline changes in the north coast area of the abandoned Yellow River Delta, whilst increases in the south of this region. The maximum variation of tidal amphtude takes place near the Radial Sandbank. （2） Following the erosion of the abandoned Yellow River Delta in the past century, the non-tidal points of M2 and K1 partial tides move to southwest gradually. （3） During the early 20th century, with the coastline changing, tidal range decreased 30 - 60 cm. From the abandoned Yellow River mouth to the Lvsi Port, the maximum increase of tidal range can exceed nearly 150 cm. From the early 20th century to the early 21st century, the tidal range increases by 20- 50 cm outside the Radial Sandbank. Whereas, the tidal range reduced near the abandoned Yellow River mouth by 30 ~ 50 cm.

黄河三角洲浅地层扰动的空间差异及其主控机制

现代黄河水下三角洲是油气开采、海底管道铺设等基础设施建设的重要地区,随着黄河经历多次改道,不同河口海域的泥沙供应、海洋动力以及人类活动等条件发生显著变化,黄河三角洲不同河口地区沉积演化出现明显差异,其地层结构的变化备受工程人员及研究学者的关注。本文基于2023年浅地层剖面数据,以整个现代黄河三角洲及其分区(刁口-神仙沟河口、现行河口、清水沟河口)为研究对象,研究黄河三角洲浅地层扰动空间分布特征,对比3个河口区浅地层扰动的差异性,结合不同河口区的泥沙供应、海洋动力等资料,揭示地层扰动差异性的主控机制。研究结果表明:(1)从典型地层扰动区的基本特征来看,黄河三角洲地区的扰动地层的总体分布呈现出随水深的增加而逐渐减少的规律。不同河口区扰动地层差异显著,其中刁口-神仙沟河口的扰动地层主要表现为数量多、埋藏深度浅的特征;清水沟河口的扰动地层以聚集分布、埋藏浅、发育规模大等为特征;而现行河口海域扰动地层以埋藏深、数量少为主要特征;(2)黄河三角洲不同区域的地层结构受入海泥沙和海洋动力等因素的影响,具有明显的空间差异性。波浪的高底剪切应力分布与地层扰动高密度区分布高度一致,波致底剪切应力是影响3个河口区域以及不同水深地层结构差异的主要动力因素,而入海泥沙供应则导致不同河口区扰动地层埋深有所差异。

黄河废弃三角洲海底冲淤演变规律研究

1976年黄河改道清水沟流路后 ,钓口流路三角洲叶瓣废弃 ,由于大量陆源沉积物供应的断绝 ,原来形成的快速堆积地形变得极不稳定 ,水下三角洲岸坡受到海洋动力快速冲蚀作用。根据长期水深资料的对比研究 ,波浪侵蚀使水下岸坡整体变缓以适应新的沉积动力环境 ,正逐渐形成新的冲淤平衡剖面。对整个研究区的水深资料进行叠加 ,总结其海底冲淤演变规律。采用 2 0 6 6 0、2 0 6 5 6、2 0 6 5 2和 2 0 6 4 8剖面上的散点 (整数水深点 )水深变化 ,结果表明废弃三角洲海底由浅水区向深水区冲淤组合呈带状分布 ,且越向深水区周期性越明显。

黄河三角洲废弃叶瓣海岸侵蚀与岸线演化

利用Landsat TM卫星遥感图像,对黄河1964～1976年间形成的三角洲叶瓣自1976年废弃以后的岸线进行了识别,选取了四个典型剖面,绘制了它们的岸线蚀退或淤进平均速率曲线.结果显示,不同剖面处天然岸线的蚀退或淤进速率很有规律.根据曲线特征将其分为蚀退期,转换过渡期和周期性波动期.现废弃叶瓣已进入周期性波动期.由于受大坝影响,不同位置岸线波动周期不同,两大坝之间约为4年,大坝西侧约为5年,岸线变化准平衡线位于1996年的海岸线附近.岸线变化速率波动幅值将随着时间的延长而减小.

波流共同作用下废黄河河口水下三角洲地形演变预测模式

通过对废黄河河口水下三角洲海域水文、泥沙、沉积和地形的调查分析 ,对组成水下三角洲 - 1 0— - 1 5m以深的平坦海床、- 5— - 1 0m间的水下斜坡、- 5m以浅的近岸浅滩三个地貌单元的水动力特征以及在波流和潮流作用下底部泥沙冲刷率的横向分布进行计算分析 ,并建立了水下三角洲地形横向剖面地形的演变预测模式。结果表明 ,在三角洲不同地貌单元内 ,由于所处不同的水动力条件和底部泥沙特性 ,出现了不同的侵蚀状态 ,其中在 - 1 0—- 1 5m以深的平坦海床 ,除了 3m以上的大浪外 ,水动力作用以强劲的潮流冲刷为主 ,目前已接近冲刷相对平衡的状态 ;在 - 5— - 1 0m间的水下斜坡 ,受波浪和潮流的共同作用 ,冲刷强度大 ,地形剖面呈继续平行后退状态 ;- 5m以浅的近岸浅滩 ,潮流作用相对较弱 ,以波浪对滩面的刷低为主 ,水深线不断向岸方向移动、滩宽变窄 ;0m以上的潮间带滩地 ,则波浪和潮流作用均较弱 ,近岸高滩接近相对稳定状态 ,有利于海岸线的工程防护。

废黄河沉积记录中来自不同河流物质的信息——基于重矿物与地球化学元素分析

在全新世时间尺度内,沉积记录主要受控于沉积物供给、输运和堆积过程等因素。对废黄河沉积记录的深入分析可以反演黄河南流夺淮过程中沉积物的"源"-"汇"关系。基于废黄河故道沉积记录中重矿物和地球化学元素特征,并结合与现代黄河沉积物的对比,揭示废黄河沉积记录中物质来源的信息。结果表明,废黄河故道沉积物中重矿物平均含量为0.19%,种类多达15余种,以稳定矿物为主,不同矿物的时空变化差异较大。废黄河故道泥质和砂质沉积物中,地球化学元素表现出明显的时空变化规律,随深度递增元素含量可分为降低、稳定和增加趋势。对比现代黄河沉积物,发现废黄河故道沉积物中稳定和极稳定矿物相对含量较高,泥质沉积物中更多地富集Zn,Ni,Al,Ba,Cu,Li,K等元素。这一差异性反映出其它不同河流物质补给而产生的影响,淮河沉积物中重矿物和地球化学元素的研究为该论断提供了佐证。

南黄海辐射沙洲趋势性演变的动力机制分析

南黄海辐射沙洲区水道及其之间的沙洲普遍存在逐渐向南偏移的趋势,对这种趋势性演变机理及驱动力的认识成为辐射沙洲区海岸开发过程中亟待解决的问题。在恢复黄河北归以来苏北黄河三角洲海岸不同发育阶段的岸线位置和水下地形的基础之上,通过所建立的潮波数学模型,研究了在苏北黄河三角洲不同演变阶段南黄海潮波系统的特征及其变化。研究表明,随着岸线后退和水下三角洲的夷平,辐射沙洲地区潮差不断增大;水动力不断加强,而且加强的区域逐渐向南偏移,这种大范围区域性水动力主轴的向南偏移有可能是导致辐射沙洲整体南移的主导因素之一。

基于PSInSAR技术的现代黄河三角洲地面沉降监测与分析

地面沉降是现代黄河三角洲地区主要的地质灾害之一,利用PSInSAR技术对覆盖现代黄河三角洲部分地区的10景ERS1/2数据进行处理,获得该研究区的地面沉降范围、沉降速率和形变时间序列情况。选取3个地面沉降范围和速率相对较大的区域进行重点分析,同时将监测结果与相应时间段的居民区分布图和油田分布图进行叠加分析,结果表明,地面沉降与石油开采、地表载荷增加具有较强的相关性。利用水准观测数据对获得的监测结果进行精度验证,结果显示PSInSAR监测结果与水准观测数据吻合,中误差达到mm级。

三角洲废弃河道演化过程及受控机制——以黄河刁口废弃河道为例

废弃河道是河流系统的重要组成部分,其沉积记录蕴含了丰富的流域内构造活动、水文特征、海平面波动等环境变化的珍贵记录。然而相比内陆河废弃河道,三角洲废弃河道的演化过程及机制研究尚显不足。1976年黄河人工改道清水沟流路,切断了刁口流路的河流水沙供给,刁口流路逐渐废弃。通过1976—2016年的Landsat遥感影像、黄河水下三角洲测深资料和刁口流路河道高程测量数据,探讨了黄河刁口流路废弃河道演化过程及其受控机制。结果表明,刁口流路废弃40年来,河口不断向岸蚀退,河道长度逐渐萎缩,但废弃河道沉积过程并未完全中止,刁口流路L7—L11河段每年约有10×10^(4) t泥沙不断充填废弃河道,河道主槽高程抬升0.3~2.0 m。海洋动力是废弃河道演化的关键动力机制,波浪对刁口流路三角洲的冲刷为废弃河道充填提供了重要的物源,潮流携带悬浮泥沙回溯废弃河道,为其提供了直接泥沙供给。

内蒙古岱海现代辫状河三角洲沉积特征及沉积模式

古代辫状河三角洲沉积在我国含油气盆地中广泛发育,并成为油气成藏的有利条件之一,但现代湖泊辫状河三角洲却发育较少,内蒙古岱海辫状河三角洲是为数不多的、发育良好的现代实例之一。为此,实地考察、研究了该辫状河三角洲的沉积特征及沉积模式,并取得以下结论性认识:1三角洲前缘没有水下分流河道,分流河道一入湖即消失,在其前方形成朵状河口坝,沿岸流将河口坝砂再次沿湖岸搬运沉积,形成席状滩;河口坝与席状滩连片,沿湖岸连续展布,河口坝厚度比席状滩大,地形上常隆起,并垂直于湖岸延伸。2辫状河入湖可以形成2种三角洲,即分流河道呈辫状河的三角洲和分流河道呈曲流河的三角洲,前者发育于三角洲形成早期阶段,三角洲平原较小、坡度较大;后者发育于三角洲形成晚期阶段,三角洲平原变大、变平缓,皆呈朵状。3早期阶段的辫状河三角洲,分流河道两岸河岸砂发育,主要为细砂;而晚期阶段则以粉砂和泥为主。4三角洲前缘砂体比平原分流河道的细,前者以砂质沉积为主,后者以砾质沉积为主。

现代黄河三角洲海岸演化研究

通过不同年代海图或地形图对比、不同年代的卫片对比、野外地质调查、不同年代潮滩剖面测量及对比等，研究了现代黄河三角洲海岸带不同时期的冲淤速率及其发展演化趋势。黄河尾闾 1996 年 6 月进行人工改道向东流入海，开始堆积现代黄河三角洲的第11 个叶瓣，推测这次改道可能是第 3 个亚三角洲形成的开始，使黄河三角洲的发展呈第一、第二、第三亚三角洲逐次向东偏北方向推进之势。现代黄河三角洲及莱州湾海岸带可分成 7 个冲淤状态不同的岸段：大口河至顺江沟岸段为相对稳定海岸段；顺江沟至挑河口岸段为弱蚀退岸段；挑河口至 106 站岸段为强蚀退岸段；106 站至孤东油田段为石堤护岸强制稳定海岸段；孤东油田至大汶流海堡岸段为强淤进岸段；大汶流海堡至淄脉沟岸段为弱淤进海岸段；淄脉沟口至胶莱河口岸段为稳定海岸段。预测 10 a 内，各海岸段的冲淤状态基本保持不变，但各海岸段的蚀退或淤进速率有逐渐减缓之趋势。人类活动对岸线的变迁有明显影响。

现代黄河三角洲粉质类土承载力确定

现代黄河三角洲粉质类土,是指1855年黄河改道以来注入渤海快速堆积的细粒沉积物,目前覆盖面积约5000 km2,主要分布于山东省东营市胜利油田所在地。选定4个研究场区地基土,进行现场系列原位土工试验,即平板载荷试验、螺旋板载荷试验、扁铲侧胀试验、标准贯入试验、静力触探试验;结合室内土工试验,分析研究黄河口新近快速堆积的细粒沉积物承载力特征值;系统比较各种试验手段确定的承载力特征值差异;以载荷试验确定的承载力特征值为标准,建立比贯入阻力Ps、标准贯入击数N、含水量w和孔隙比e与承载力特征值fk间的回归方程,为现代黄河三角洲地区粉质类土地基承载力特征值确定提供科学依据。

近代黄河三角洲植被覆盖度时空变化分析

为了深化研究近代黄河三角洲植被演化规律与机理,指导该地区合理开发和保护植被资源,选用Landsat等卫星遥感数据结合野外调查数据,利用像元二分模型估算并分析了该地区1986—2015年长时间序列植被覆盖度时空变化过程及影响因素(水分条件、盐分条件、人类活动)。结果表明,该地区近30年植被覆盖度时空变化明显,(1)空间变化上,植被覆盖度呈现由西南向东北递减,由河流两岸向沿海递减的趋势,并且随着时间变化,这两种趋势越来越明显。随着人类活动加强,植被覆盖破碎化显著。(2)时间变化上,1986—2015年该地区植被覆盖度总体呈上升趋势,由1986年的36.77%上升为2015年的37.83%。中高、高植被覆盖面积增幅最大,达到314.96 km^2。低植被覆盖度区逐渐转为高植被覆盖度区,特别是2001—2015年,随着研究区生态环境逐渐变化,转化速度逐渐加快。(3)环境因子与植被覆盖度具有一定的相关性,采用基于像元的空间分析法分析不同时滞月降水量与近代黄河三角洲植被覆盖度相关性,发现月降水量与植被覆盖度有较大关系。通过遥感指数构建土壤反演模型,得到盐分空间分布,并进行相关性分析,发现土壤盐分与植被覆盖度相关性系数为-0.331(P<0.02),近代黄河三角洲盐碱化对植被生长有一定阻碍作用。人类活动对植被覆盖度的影响主要以农业为主,通过对植被覆盖度与耕地进行相关性分析,得相关性系数为0.452(P<0.02),近代黄河三角洲耕地的开发,在一定程度上促进了该地区植被覆盖度的恢复。