Modern Yellow River Delta Research Articles

Records of Compaction Subsidence of Argillaceous Sediments in the Modern Yellow River Delta

The distributary lobe of the modern Yellow River Delta formed after 1855 was 15 m in thickness before it was abandoned, where the compaction subsidence has reached as high as 2.28∼3.87 m in the past 30 years. The compaction ratio of clayey silty sand (25.8%) is 1.7 times greater than that of silty sand (15.2%). It means that the compaction process has basically terminated. On the other hand, the compaction subsidence of underlying sediment is quite limited and shows an insignificant difference. For example, for the underlying sediment of 20∼30 m in thickness, the subsidence varies between 0.2 and 0.28 m. The average compaction ratio of clayey silty sand is 0.91%, while that of silty sand is 1.19%, and the average compaction ratio of all sediment is 1%. There's a negative exponential function relationship between porosity and burial depth of the sediment, and the higher the clay content, the more difficult it is for pore water to drain. The superficial sediments contribute more to the compaction subsidence than the underlying strata.

Editorial Note "Effects of water discharge and sediment load on evolution of modern Yellow River Delta, China, over the period from 1976 to 2009" published in Biogeosciences, 8, 2427–2435, 2011

E. Boss1, J. Kesselmeier2, S. W. A. Naqvi3, and A. Neftel4 1University of Maine, 5706 Aubert Hall, Orono ME 04469-570, USA 2Max Planck Institute for Chemistry, Biogeochemistry, Joh.-J.-Becher Weg 27, 55128 Mainz, Germany 3National Institute of Oceanography, Chemical Oceanography Division, 403004 Dona Paula, Goa, India 4Agroscope Reckenholz Tanikon Research Station, Air Pollution and Climate Group, Reckenholzstrasse 191, 8046 Zurich, Switzerland

The Sedimentary Environment of Current Estuary and Abandoned Estuary at the Modern Yellow River Delta

Based upon statistics of sediment parameters and sediment moving modes from probability cumulative distribution curves, and combined with topography and hydrodynamics, the sedimentary environment at the intertidal flats of Qing 8 estuary (1996-now) and Diaokou estuary (1964-1976) at the Yellow River Delta was discussed in depth in present study. The results demonstrated that sediment grain size parameters can clearly reveal hydrodynamic condition of the sedimentary environment. Core C1 at current estuary was divided into four layers. The corresponding hydrodynamic conditions from top to bottom varied from strong to fluctuating between strong and weak, and finally to weak. Meanwhile, Core A1 at abandoned estuary can be divided into three layers and corresponding hydrodynamics from top to bottom changed from fairly strong to rather strong. Furthermore, the sedimentary facies of two cores were identified and they depended on water and sediment discharge from the Yellow River.

Effects of water discharge and sediment load on evolution of modern Yellow River Delta, China, over the period from 1976 to 2009

Abstract. The Yellow River, which is the second largest river in China, is regarded as the world's largest contributor of fluvial sediment load to the ocean. In recent decades, the dramatic reduction in water discharge and sediment load due to climate change and human activities in the drainage basin has greatly constrained the evolution process of Yellow River delta. We highlight how runoff and sediment load discharged into sea affected extension of shoreline length and area of modern Yellow River delta during 1976–2009 based on remote sensing interpretation and long-term monitoring data in hydrological station. Average runoff of 207.47 × 108 m3 yr−1 and average sediment load of 4.63 × 108 m3 yr−1 were discharged into the sea from 1976 to 2008. The annual runoff reduced by ~59.7 % in 1990–2002 and annual sediment load reduction up to ~72.1 % in 2003–2008. Both shoreline length and area of Yellow River Delta extended overall in the studied period, but with decreasing rates in accordance with changes of runoff and sediment load. High increasing rate of shoreline length of ~3.63 km yr−1 and quick area extension of ~16.26 km2 yr−1 were observed in 1976–1985. Since 1996 however, the average increase rate of shoreline length and area decreased to ~0.80 km yr−1 and ~3.94 km2 yr−1, respectively. In addition, the fluctuated changes of shoreline and area were great and the net negative increase of land area was occurred during this period. There exist significant exponential relationships between the accumulated sediment load and extensions of shoreline length and the area during the evolution of the modern Yellow River Delta. Our results indicate that the evolution of shoreline and change of area of the Yellow River Delta are directly affected by the dramatic reduction of runoff and sediment load, which are much close related human being activities in Yellow River drainage basin in recent decades.

Plant distribution can be reflected by physiological responses to salinity of three submerged macrophytes from the Modern Yellow River Delta

With 4 figures Abstract: Patterns of distribution vary greatly among species in the Modern Yellow River Delta, the largest es- tuarine wetland in China. Although salinity has been considered as the key factor determining plant distribution patterns in this delta, the intrinsic mechanisms accounting for distribution patterns are far from clear. To this end, three submerged macrophytes (Ceratophyllum demersum L., Potamogeton perfoliatus L. and Myriophyllum spica- tum L.) were grown in 0.2 (control), 1.2, 2.4 and 3.6 psu salinity waters. The relative growth rate (RGR), content of MDA (malondialdehyde) and activities of the enzymes (SOD - superoxide; POD - peroxidase; CAT - catalase; APX - ascorbate peroxidase) in leaves were investigated. The RGR of M. spicatum decreased only in the 3.6 psu treatment, while those of C. demersum and P. perfoliatus declined significantly with increasing salinity. Compared to the control, RGR of M. spicatum, C. demersum and P. perfoliatus decreased by 31.8 %, 78.5 % and 71.0 % while the MDA content increased by 12.0 %, 35.9 % and 28.3 % in the 3.6 psu treatment, respectively, indicating that M. spicatum had a higher salinity tolerance ability than the other two species. The activities of four antioxidative enzymes increased with increasing salinity in M. spicatum. However, for C. demersum and P. perfoliatus, the four antioxidative enzymes increased in the 0.2 to 2.4 psu treatments, but decreased subsequently in the 3.6 psu treat- ment except for the activities of SOD and APX in C. demersum. It is concluded that antioxidative enzymes can protect M. spicatum from oxidative stress under higher salinity, but that this mechanism is absent in C. demersum and P. perfoliatus.

A PRELIMINARY DISCUSSION ON STATISTICAL DISTRIBUTION CHARACTISTICS OF THE NEOTERIC AND MODERN YELLOW RIVER DELTA

Being one of the three biggest bayou deltas of China, the neoteric and modern Yellow River Delta, raised since 1855, is composed of seven sub-deltas. Due to the lack of laboratory data, this paper has to use Landsat TM remotely-sensed data to analyse band ratios and principal components. The authors enhanced the spectral information of ferruginous oxides and analysed frequency histograms and statistical values of the second principal component of seven sub-deltas. On such a basis, the surface environmental differences of the neoteric and modern Yellow River Delta are discussed tentatively and briefly, which provides a useful train of thought for applying the remote sensing technology to solving geographical problems.

Coastal environmental monitoring using remotely sensed data and GIS techniques in the Modern Yellow River delta, China

On the basis of remote sensing and GIS techniques, the Landsat data obtained in 1987, 1996, and 2008 were used to examine coastline changes in the Modern Yellow River (MYR) delta in China. The coastal land lost and gained illustrations were derived, the rates of coastal change were estimated, and the coastal parts that experienced severe changes were identified. The results revealed that the accretion rates in the MYR delta coast has been decelerating while the accretion effect remained. Taken the artificial coast from the south of ShenXianGou (SXG) to Gudong Oil Field (GOF) as the landmark, the coast in the south of the landmark showed an accretion pattern, while the coast in the west of the landmark showed an erosion pattern. Wherein, the coast from Chao River Estuary (CRE) to Zhuang 106 (Z106) showed an erosion pattern with the transition from erosion to accretion and the accelerated rates from east to west. The coast from Z106 to the south border of GOF also showed erosion pattern but significant differences existed among the internal coastal parts. The coast from the south border of GOF to XiaoDao River Estuary (XDRE) showed a pattern from rapid accretion to dynamic balance of accretion/erosion, and the trend towards erosion. The coast from XDRE to XiaoQing River Estuary (XQRE) showed slow accretion pattern. Human activities have heavily influenced the natural evolution of the MYR delta coast.

Seed germination traits of two plant functional groups in the saline deltaic ecosystems

Aims Salt stress resulting from soil salinization is one of the driving forces of the land degradation throughout the world. The modern Yellow River delta is one of the most saline areas in China. Phytoremediation can be an effective way to restore the salinized ecosystems, which requires selecting appropriate plant species. This study explored the germination responses of common plant species from contrasting habitats in the Yellow River delta to varying salinity, offering experimental information for ecosystem restoration in the Yellow River delta. Methods In this study, 15 common plant species from the Yellow River delta were divided into two groups (high-salinity and low-salinity groups) by their natural habitats using Canonical Correlation Analysis. Seeds of each species were treated with five salinity levels (0, 5, 10, 20 and 30 ppt), using a randomized complete block design, and germinated seeds were counted and removed daily for 28 days to calculate the final germination proportion and mean time to germination. The germination responses of seeds to salinity treatments were compared between the two groups. Important Findings In relation to salinity, seed germination behavior of the test species was closely related to the salinity level of the habitats over which they were distributed. Species from the habitats with higher salinity had generally higher final germination proportion but shorter mean time to germination than those from the habitats with lower salinity in all of five salinity treatments used. The final germination proportion and mean time to germination of low-salinity group species were more sensitive to salinity than those of high-salinity group species. Selecting the species with high final germination proportion and short mean time to germination is important for restoration of salinized land.

Formation of Plant Communities of the Newly Created Wetland in Modern Yellow River Delta

To explore the cause of plant vegetation distributed on the newly created wetland in estuary of modern Yellow River Delta, we took field-based observation of the wetland plant diversity of the Yellow River Delta, Shandong, China. Based on the results of field investigation, we studied the effects of salinity on germination characteristics of four dominant species in wetland of Yellow River Delta, i.e. Suaeda salsa, Apocynum venetum, Phragmites australis and Typha orientalis.The germination conditions of the four dominant emerging plants at 0, 50, 100, 150, 200, 250 and 300mM NaCl were studied, the results indicated that all species had a trend of decreased germination percentage and rate of germination with the increase of salinity levels, but the inhibitory effect of salinity on the germination percentage of each was different. S. salsa and A. venetum had higher tolerance of salinity than P. australis and T. orientalis. Germination percentage and germination rate of seeds of the four species were significantly affected by salinity.In conclusion, the results of seeds germination of the four dominant species in the newly created wetland were accorded with the results of field investigation of plant community distribution along the gradients of environmental salinity, and salinity is one of the most pivotal factors limited the distribution of the plant vegetation in the newly created wetland of Yellow River Delta.

Dioxin-like Polychlorinated Biphenyls Contamination and Distribution in Soils from the Modern Yellow River Delta, China

The concentrations of 12 dioxin-like Polychlorinated Biphenyls (dl-PCBs) were determined from 37 soil samples collected from the modern Yellow River Delta (China) in March 2006. The PCB concentrations were determined by dual capillary GC-ECD. The total dl-PCBs concentrations were in the range of 108.7 to 2153 ng/kg with an average of 800.5 ng/kg. The toxic equivalency (TEQ) in this area varies from 2.3 × 10− 5 to 9.5 × 10− 5 ng-TEQ/kg, so the delta is slightly polluted by PCBs. PCB118, the main congener, accounted for 46.7% of the total dl-PCB. More than 60% dl-PCBs were penta-PCBs. The spatial distribution of the dl-PCBs is discussed in detail. The distribution of the PCBs suggests that water runoff is the main source of the total contaminant burden in the delta, and that atmospheric precipitation plays an important role.

Interspecies variability of Dioxin-like PCBs accumulation in five plants from the modern Yellow River delta

To investigate the interspecies variance of Dioxin-like polychlorinated biphenyls (DL-PCBs) in the plants from modern Yellow River delta, the concentrations of 12 DL-PCBs congeners were examined in five plant species and their associated soils. The DL-PCBs concentrations in plants (2.32–287.60 ng/kg dry weight) were low compared to most published literature, and the concentrations and ratios of DL-PCBs congeners in plants varied greatly among species. The properties of plants and PCBs were then studied to explore the factors affecting the interspecies variance of DL-PCBs accumulation. The plants with the smallest variance of morphological and physiological characteristics ( Imperata cylindrical var. Major and Phragmites australis (Cav.) Trin. ex Steud) had the most similar accumulation patterns of DL-PCBs among the species tested. As the octanol–air partitioning coefficient ( K oa) of the DL-PCBs increased, interspecies variance decreased on the whole plant level. Interestingly, the correlation between the DL-PCBs concentrations in plants and log K oa of congeners was found to be significant for annual plants, but for perennial plants it was not significant. Thus the patterns of uptake of DL-PCBs are different between annual and perennial plants.

Characteristics of landscape information Tupu of the Yellow River swings and its subdeltas during 1855–2000

Based on the theories and methods of cartography on spatial pattern and temporal evolution in Geo-information Tupu (Carto-methodology in Geo-information, CMGI) and the quantitative measurements of pattern and process in landscape ecology, the methodology of landscape information Tupu in studying the swing process of the Yellow River (YR) over the Yellow River Delta (YRD) during 1855–2000 has been demonstrated. The main content includes: (1) methodology of landscape information Tupu; (2) evolution process Tupu of YR rump channels; (3) evolution process Tupu of the 7 pieces of subdeltas in YRD during 1855–2000; (4) landscape information Tupu of the modern YRD and the current YRD; (5) landscape information Tupu of YR rump channels on the 7 pieces of subdeltas during 1855–2000; and (6) corridor-matrix landscape information Tupu by YR swings. The methodology of landscape information Tupu here is still primary but we hope that it could provide a new tool for exploring an integrated research on spatiotemporal approaches for landscape “pattern and process”.

Plant community succession in modern Yellow River Delta, China

Data were collected in different successional stages using a simultaneous sampling method and analyzed through quantitative classification method. Three large groups and 12 classes were made to represent the community patterns of three succession stages and 12 succession communities. The succession series of plant community in the study area was as follows: saline bare land-->community Suaeda salsa-->community Tamarix chinensis-->grassland. Succession degree and succession process of 12 succession communities were calculated. Most of these communities were in the lower succession stage, however, community Phragmites communis+Glycine soja and community Imperata cylindrica+G. soja were close to the succession stage of grassland climax. Five species diversity indices were used to study the changes in species richness, species evenness and diversity during succession of community. Heterogeneity index and richness index increased gradually during the community succession process, but species evenness tended to decrease with succession development. The relation between succession and environment was studied by ordination technique, and the results showed that the soil salt content was an important factor to halarch succession of the modern Yellow River Delta. It affected community structure, species composition and succession process.

An Experiment Study of Erosion Characteristics of Sediment Bed at the Yellow River Delta

The modern Yellow River Delta is formed by fine-grained sediments through fast transportation and accumulation. Its coast is characterized by partially consolidated bed structure, high water content and weak erosion resistance. Despite recent advances in numerical morphodynamic modeling techniques, the current ability to predict long-term coastal changes at the Yellow River Delta is hampered by the lack of reliable data on the erosion resistance of the sediments deep in the bed. This paper describes a laboratory-based erosion study using a 30 m sediment core collected from the tidal flat on the northern coast of the Yellow River Delta in April 2004. The influence of various sediment properties such as bed stratification, grain composition, wet bulk density and water content on the measured erosion resistance has been analyzed in detail. The results reveal that there exist a definite negative relationship between the critical erosion shear stress and water content or median diameter, and also a clear positive relationship between the critical erosion shear stress and clay content. For the sediments of the same type, there was a positive relationship between the critical erosion shear stress and wet bulk density. It was also found that the erosion resistance changes considerably through depth with the lowest being near the surface and the highest at a depth of 9.1-13.5 m. The relationship between erosion rate and shear stress for erosion was shown to be dependent in a complex way on the grain distribution, sedimentation structure, wet bulk density and water content of the sediments. A number of distinct erosion behavior have been identified and although in most cases the erosion rate (ε) can be related linearly to the net bed shear stress (τ – τc), further study is needed to establish the erosion-stress relationship for the case were the erosion seems to show undulating behavior.

Changing pattern of accretion/erosion of the modern Yellow River (Huanghe) subaerial delta, China: Based on remote sensing images

The Yellow River shifted from the Diaokou course to the Qingshuigou course in 1976, and shifted again at the north bank of the Qingshuigou course in 1996. As a result, the entire modern Yellow River Delta has experienced complicated patterns of erosion and accretion. Multitemporal remote sensing data of Landsat MSS and TM from 1976 to 2000, totaling twenty scenes, were used to examine the changing pattern of accretion and erosion of the modern Yellow River subaerial delta with GIS tools. During the period 1976 to 2000, the maximum erosion occurred at the head of the last two abandoned promontories, Diaokou and Shenxiangou promontories, where the coastline retreated landward over − 7 and − 4.5 km, respectively, with mean net erosion rates of − 0.29 and − 0.19 km/a, respectively. In contrast, the maximum accretion occurred at the head of the Qingshuigou Promontory where the coastline advanced seaward over 20 km with a mean net accretion rate of 0.83 km/a. The coastline at the head of the Q 8 Promontory also advanced seaward 7 km with a mean net accretion rate of 0.29 km/a during the period 1996 to 2000. Total area of the Diaokou and Shenxiangou promontories was reduced by − 141.3 km 2 with a mean net erosion rate of − 6.03 km 2/a. Total area of the Qingshuigou and Q 8 promontories increased by 384.16 and 11.88 km 2, respectively, with mean net accretion rates of 16.4 and 3.03 km 2/a, respectively. Relative to the Diaokou, Shenxiangou and Qingshuigou promontories, the west area of the Diaokou Promontory and south area of the Qingshuigou Promontory were relatively stable, although minor erosion occurred. The general pattern of accretion and erosion of the modern Yellow River subaerial delta was divided into three stages: rapid accretion stage (1976–1984), accretion–erosion adjustment stage (1985–1995), and slow erosion stage (1996–present). The factors affecting the pattern of erosion and accretion over the Yellow River Delta, such as structural geology, the Yellow River sediment discharge, coastal processes, meteorological conditions, human activity, sea level rise and land subsidence were summarized. The cumulative area of increase over the entire subaerial delta is closely correlated with the cumulative Yellow River sediment discharge. Wave-induced longshore current is the major driving force to transport sediment from eroded areas along the last two abandoned promontories, Diaokou and Shenxiangou promontories, mostly westerly and partially easterly. Together with these coastal processes is the geographical shift of the Yellow River course associated with its discharge regime after 1976, leading to the accretion along the present Qingshuigou Promontory and then the Q 8 Promontory.

A sediment budget of the lower yellow river, china, over the period from 1855 to 1968

This study investigates the sediment fluxes through the Yellow River sediment routing system, which are among the largest in the world, by constructing a sediment budget of the system over the period from 1855 to 1968. The framework of the sediment budget includes four functional units with the upper and middle reaches of the river as the sediment source and its lower reaches, its delta, and the deep sea as the sediment sinks. Sediment yield from the source and amounts of deposition in the lower Yellow River and the modern Yellow River delta were estimated for completing the sediment budget. The sediment budget produced for the period from 1855 to 1968 was characterized by a sediment input of 1.837 × 1011 tonnes and a distribution of the sediment between the lower Yellow River, the delta, and the deep sea of 64%, 33%, and 3%, respectively. The details of the sediment budget show that the importance of sedimentation in the lower Yellow River changed greatly with variations in the condition of the dykes and other human activities. A comparison of the sediment budgets of the delta for different timescales shows that the proportion of sediment dispersed to the deep sea decreases as the timescale over which the sediment fluxes are investigated increases.

Sedimentation in the Yellow River delta. Part III. Seabed erosion and diapirism in the abandoned subaqueous delta lobe

Abstract Historical bathymetry, satellite remote sensing and river discharge data have been used to examine the evolution of an abandoned delta lobe in the northern area of the modern Yellow River delta. Results show three stages of evolution in the subaqueous delta slope after lobe abandonment: (1) rapid erosion stage; (2) slow erosion stage; and (3) erosion–accumulation adjustment stage. According to 1:10,000 bathymetry data and high-resolution seismic profiles, diapirism in the subaqueous abandoned delta lobe is closely related to seabed erosion, which mainly occurs in the middle part of subaqueous delta slope. Diapirism results from the deformation of soft, fine-grained prodeltaic sedimentary stratum when the accumulation body on the soft stratum is removed in rapid erosion stage. The maximum accumulation centre in the delta lobe during growth coincides with the maximum erosion centre in the delta lobe abandonment phase. The diapir body occurs there. Distinguishing from diapirism in the Mississippi delta, three stages of the soft stratum deformation and diapirism are established in the Yellow River delta. The mobile strata and its diapirism are destructive to the offshore engineering facilities.

Sedimentation in the Yellow River delta, part II: suspended sediment dispersal and deposition on the subaqueous delta

Rapid deposition and suspended sediment dispersal off the modern Yellow River mouth has been examined from the data of topographic maps (1 : 25,000), suspension and bed sediments, current and salinity, which were measured in the field. The results show that the sedimentation rate of the mouth bar is the highest of all the environments of deposition in the modern Yellow River delta. About 30–40% of the sediment that the river transports into the sea has been deposited within the mouth bar area. Rapid deposition of the mouth bar results mainly from kinetic energy dissipation of the river under the influence of three ambient mechanisms. These three mechanisms occur simultaneously as shear front movement, which obstructs the river's jet-like flow, small-scale circulations where large velocity gradients occur and the `bulldozer' effect of the tide sensitive zone in the estuary at ebb. Based on the analysis of morphologic changes, the mouth bar can be divided into two morphologic types: one is the double-lobe and single-channel type and the other double-channel and single-lobe type. Weak hyperpycnal plumes with small density differences between the river flow and ambient water dissipate rapidly and deposit about 20% of the river sediments on the delta front slope, while hyperpycnal underflows from the river mouth can go through the steep delta front slope to form a rise apron along the upper part of the prodelta. Grain size analysis of suspended sediment shows that the flow can be divided into three layers: a tide layer in the upper part, and a hyperpycnal layer in the lower part, (these two layers are normally graded), and a transition layer with inverse grading in the mid-part. The fine suspended sediments have been transported in the hypopycnal plume layer into the prodelta and deep sea, such as the North Huanghai Sea (North Yellow Sea). This study indicates that the tidal current field has dominated the distribution of deposition of sediment on the subaqueous delta and the movements of the river effluent and hyperpycnal underflows.

Overbank and channelfill deposits of the modern Yellow River delta

The Huanghe is noted for its high transport rate of silt and clay, which may reach depth-averaged values of 200 kg m −3 during peak discharge. The sediment load transported through the river on entering the delta plain, amounts to 10 12 kg per year. In contrast to most other large deltas only one distributary channel is active at any one time. The high sediment load causes the rivermouth to prograde at a yearly rate of 1–4 km into the shallow (less than 20 m deep) Bohai gulf. The vertical aggradation of the channel belt and mouth bar complex is also rapid (decimetres per year on average), so that after a normal average of twelve years increasing channel instability and avulsion create the start of a new delta lobe. A series of satellite images covering the last fifteen years has provided insight in the evolution of the river pattern as well as the progradation of the delta front. A newly developed distributary passes from a multichannel to a single, straight channel system, and ends with the formation of meanders. The protruding mature delta lobe shows a radiating pattern of crevasse channels. Overbank/ crevasse deposits are made of vertically stacked dm-scale waning flow sequences, structurally characterized by (from bottom to top) small scour-and-fills, even (parallel) lamination, and climbing-ripple crosslamination. Accumulation rates on crevasse splays can be predicted on the basis of estimated river sediment discharge. It can be concluded that each sequence has been deposited within a few hours, and that tidal waterlevel fluctuations may have played a role in the generation of a single sequence.

Behavior of marine sediment under storm wave‐loading

The behaviors of marine sediment under storm wave loading are critical to the stability of the seafloor. This study analyzes measurements of seafloor motion obtained from the Modern Yellow River Delta, China, in a storm season of 1987. Using these field data, we examined the elastic behavior of seafloor sediment by calculating the variation of its shear modulus, and estimated the damage potential mobilized within the sediment. Results show that the shear modulus of sediment reduces under storm wave loading, and the reduction can be up to 77.7% of the original value during a 24‐hour storm. Moreover, the S‐N strength curve for sediments on the Yellow River Delta is determined for the first time in this article.