Examining the evolution of tidal creeks in the Huanghe River delta using multi-temporal Landsat images

Coastal tidal creeks are important channels for exchanges of material and energy between sea and land,and play an important role in the ecological protection of tidal flats.Although tidal creeks have evolved differently in various regions,the evolutionary process of tidal creeks in the Huanghe(Yellow)River delta of China,one of the most active deltas worldwide,is not entirely clear.Therefore,the evolution of tidal creeks in the delta from 1981 to 2021 was investigated by quantitatively analysing the tidal creeks and developing a standard for dividing their evolution periods.Visual interpretation and supervised classification methods were applied to the Landsat images to extract the tidal creek network,and 17 groups of tidal creek systems were selected.Results indicate that Creek S 1 was the most developed creek for having 113 tidal creeks totaling 65.8 km in length,while Creek E 3 had the fastest growth rate for having average annual increase of 1.9 km.Meanwhile,the level of tidal creeks increased,the average and median lengths of tidal creeks increased,and the number of tidal creeks decreased since 1981.The evolution of the tidal creek system could be divided into four stages,namely,rising,developing,stabilizing,and degrading.Analyses of a representative tidal creek show that there was no degenerated tidal creek during the rising period,with an increase in the number of 50 and a length increase of 57.9 km between 1981 and 1989.The proportion of new tidal creeks in the developing period was more than 50%and the new tidal creeks in the stabilizing period were equal to the degraded tidal creeks.Extinct tidal creeks were greater than 50%during the degrading period.There was no fixed order of tidal creek evolution in each period,and there may be a skip in evolution.Our findings provided a reference for studying the evolution of tidal creeks.

MODERN SEDIMENTATION RATES AND SEDIMENTATION FEATURE IN THE HUANGHE RIVER ESTUARY BASED ON ^(210)Pb TECHNIQUE

Based on Pb technique, sedimentation rates of 11 cores collected from the Huanghe River estuary were determined. CaCO3 distribution of 4 cores chosen from among these was measured. Profiles of 210Pb in the cores showed that the distribution of 210Pb activity decayed with depth, appeared in stages and in more than one segment. The sedimentation rates,210Pb and CaCO3 data have similar distribution trend in the 4 cores. Jhe profiles of Pb and CaCO3 were used to study sedimentation in -tensity, transportation trend of material and sedimentation features in the coring area.

CHEMICAL WEATHERING PROCESSES AND ATMOSPHERIC CO_2 CONSUMPTION OF HUANGHE RIVER AND CHANGJIANG RIVER BASINS

Rock weathering plays an important role in studying the long-term carbon cycles and global climatic change. According to the statistics analysis, the Huanghe (Yellow) River water chemistry was mainly controlled by evaporite and carbonate weathering, which were responsible for over 90% of total dissolved ions. As compared with the Huanghe River basin, dissolved load of the Changjiang (Yangtze) River was mainly originated from the carbonate dissolution. The chemical weathering rates were estimated to be 39.29t/(km(2).a) and 61.58t/(km(2).a) by deducting the HCO3- derived from atmosphere in the Huanghe River and Changjiang River watersheds, respectively. The CO2 consumption rates by rock weathering were calculated to be 120.84 x 10(3)mol/km(2) and 452.46 x 10(3)mol/km(2) annually in the two basins, respectively. The total CO2 consumption of the two basins amounted to 918.51 x 10(9)mol/a, accounting for 3.83% of the world gross. In contrast to other world watersheds, the stronger evaporite reaction and infirm silicate weathering can explain such feature that CO2 consumption rates were lower than a global average, suggesting that the sequential weathering may be go on in the two Chinese drainage basins.

The fractal characteristic change in the Huanghe River Estuary due to the hydrodynamic conditions’variation

The study area lies in the subaqueous delta, which came into being in 1964 - 1976. Oneoil-field road has been built for exploring petroleum to form a wave barrier. The hydrodynarnic conditions on the north side of the road are relatively violent, on the contrary the hydrodynarnic conditions on the south side of the road are nearly placid. This makes the study area a natural laboratory for studying the influence of the hydrodynarnic conditions on the fractal characteristics of the tidal flat. Selecting an area is named Case Ⅰ on the side of stronger hydrodynarnic activities and an area is named Case Ⅱ on the other side. Measuring the topography and sampling and analyzing the granulometrical composition, it is found that the hydrodynarnic conditions have fatal influence on the surface fractal dimensions and the granulometrical fractal dimensions of the area. In Case Ⅰ , which has strong hydrodynarnic conditions, the surface fractal dimensions are obviously larger than those of Case Ⅱ , and the granulometrical fractal dimensions are relatively smaller than those of Case Ⅱ , the surface fractal dimensions of Case Ⅰ decrease quickly with the increase of grid size; the granulometrical fractal dimensions are disperse, while the hydrodynarnic conditions of Case Ⅱ are just reverse. A sampling line and a core sampling on each side of the road are selected. It is found that on the south side of the road the granulometrical fractal dimensions vary regularly in the line and with the depth, the farther apart from the road, the smaller the fractal dimensions, and the deeper the sampling position the larger the fractal dimensions, while granulometrical fractal dimensions on the north side of the road have no such regularity pattern. The mechanism of the influence of the hydrodynarnic conditions on the fractal characteristics is discussed.

Impacts of Climatic Factors on Runoff Coefficients in Source Regions of the Huanghe River

Runoff coefficients of the source regions of the Huanghe River in 1956-2000 were analyzed in this paper. In the 1990s runoff of Tangnaihai Hydrologic Station of the Huanghe River experienced a serious decrease, which had attracted considerable attention. Climate changes have important impact on the water resources availability. From the view of water cycling, runoff coefficients are important indexes of water resources in a particular catchment. Kalinin baseflow separation technique was improved based on the characteristics of precipitation and streamflow. After the separation of runoff coefficient （R/P）, baseflow coefficient （Br/P） and direct runoff coefficient （Dr/P） were estimated. Statistic analyses were applied to assessing the impact of precipitation and temperature on runoff coefficients （including Dr/P, Br/P and R/P）. The results show that in the source regions of the Huanghe River, mean annual baseflow coefficient was higher than mean annual direct runoff coefficient. Annual runoff coefficients were in direct proportion to annual precipitation and in inverse proportion to annual mean temperature. The decrease of runoff coefficients in the 1990s was closely related to the decrease in precipitation and increase in temperature in the same period. Over different sub-basins of the source regions of the Huanghe River, runoff coefficients responded differently to precipitation and temperature. In the area above Jimai Hydrologic Station where annual mean temperature is -3.9℃, temperature is the main factor influencing the runoff coefficients. Runoff coefficients were in inverse relation to temperature, and precipitation had nearly no impact on runoff coefficients. In subbasin between Jimai and Maqu Hydrologic Station Dr/P was mainly affected by precipitation while R/P and Br/P were both significantly influenced by precipitation and temperature. In the area between Maqu and Tangnaihai hydrologic stations all the three runoff coefficients increased with the rising of annual precipitation, while direct runoff coefficient was inversely proportional to temperature. In the source regions of the Huanghe River with the increase of average annual temperature, the impacts of temperature on runoff coefficients become insignificant.

Spatiotemporal distribution of fish eggs and larvae in the Huanghe(Yellow) River estuary, China in 2005–2016

Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in a fishery. As the fifth largest river estuary in the world, the Huanghe (Yellow) River estuary (HRE) is a typical estuary that has been seriously aff ected by human activities. Annual surveys on ichthyoplankton and environmental factors were conducted in the months of May of 2005 and 2009-2016 in the HRE to investigate the spatiotemporal distribution of fish eggs and larvae and the associated infl uencing factors. A total of 23 and 20 species of eggs and larvae, respectively, were collected. The dominant orders were Perciformes (51.2%) and Clupeiformes (25.6%). The average number of fish species eggs and larvae were 6.0 and 4.1 in average abundance of 0.91 and 0.13 ind./m^3 , respectively. The dominant species were mainly low-commercial-value small-sized fishes, such as Clupanodon punctatus , Harengula zunasi, and Acanthogobius, whereas certain traditional commercial fishes, such as Trichiurus lepturus , and Clupea pallasii, were not seen. Analysis of the fish egg and larval community revealed four temporal assemblages and two spatial assemblages. Salinity was the main factor on the spatial distribution of ichthyoplankton communities, the species number and Shannon-Weiner diversity index (H′) of the fish egg and larval community near the river mouth with lower salinity were signifi cantly lower than the community far away from the river mouth with higher salinity. In addition, increases of water temperature promoted the number and abundance of fish species eggs, and the areas of abundant prey tended to have a more diversified and abundant of ichthyoplankton species. In overall, overfishing, dam construction, and other human activities were the main drivers that led to the substantial decline in fishery resources in the HRE.

Nitrogen Biological Cycle Characteristics of Seepweed(Suaeda salsa) Wetland in Intertidal Zone of Huanghe(Yellow) River Estuary

From April 2008 to November 2009, the nitrogen （N） cycle of plant-soil system in seepweed （Suaeda salsa） wetland in the intertidal zone of the Huanghe （Yellow） River estuary was studied. Results showed that soil N had sig- nificant seasonal fluctuations and vertical distribution, and the net N mineralization rates in topsoil were significantly different in growing season （p 〈 0.01）. The N/P ratio （9.87 ±1.23） of S. salsa was less than 14, indicating that plant growth was limited by N. The N accumulated in S. salsa litter at all times during decomposition, which was ascribed to the N immobilization by microbes from the environment. Soil organic N was the main N stock of plant-soil system, accounting for 97.35% of the total N stock. The N absorption and utilization coefficients of S. salsa were very low （0.0145 and 0.3844, respectively）, while the N cycle coefficient was high （0.7108）. The results of the N turnovers among compartments of S. salsa wetland showed that the N uptake amount of aboveground part and root were 7.764 g/m2and 4.332 g/m2, respectively. The N translocation amounts from aboveground part to root and from root to soil were 3.881 g/m2 and 0.626 g/m2, respectively. The N translocation amount from aboveground living body to litter was 3.883 g/m2, the annual N return amount from litter to soil was more than 0.125（-） g/m2 （minus represented immobili- zation）, and the net N mineralization amount in topsoil （0-15 cm） in growing season was 1.190 g/m2. The assessment of N biological cycle status orS. salsa wetland indicated that N was a very important limiting factor and the ecosystem was situated in unstable and vulnerable status. The S. salsa was seemingly well adapted to the low-nutrient status and vulnerable habitat, and the N quantitative relationships determined in the compartment model might provide scientific base for us to reveal the special adaptive strategy orS. salsa to the vulnerable habitat in the following studies.

GEOCHEMICAL CHARACTERISTICS OF PHOSPHORUS NEAR THE HUANGHE RIVER ESTUARY

An improved sequential extraction method was used to extract and determine 7 forms of phosphorus exchangeable or loosely sorbed P (Ads P), aluminum bound P (Al P), iron bound P (Fe P), occluded P (Occ P), authigenic apatite plus biogenic apatite plus CaCO 3- associated P (CFAP P), detrital apatite P (FAP P), and organic bound P (Org P) in suspended matter and surface sediments of the Huanghe River (Yellow River), its estuary and nearby shelf. The concentrations of dissolved inorganic and organic P in river water were also determined. A dissolved P flux of 1.6 billion grams per year, solubilized P flux of 281 billion grams per year, and buried P flux of 588 billion grams per year from the Huanghe River to the Bohai Sea were calculated using the concentrations of P determined in the water column, suspended matter and sediments. Due to the high suspended load and low discharge of the Huanghe River, the direct contribution of dissolved P carried in solution by it to the Bohai Sea is minor compared to the solubilized P released from the suspended matter and sediments. More than two thirds of the total P transported by the Huanghe River is deposited and buried in marine sediments. Decomposition of riverine organic matter which releases organic bound P is an essential source of dissolved/solubilized P in the sea.

Studies on the regional feature of organic carbon in sediments off the Huanghe River Estuary waters

Organic carbon (OC) in definitely small area sediments(according to marine dimension)off the Huanghe River Estuary is investigated in order to evaluate the feature of regional difference of physical and chemical properties in marginal sea sediments.The distributions of OC in sediments with natural grain size and the relationship with the pH,Eh ,Es and Fe3+/Fe2+ are discussed.In addition,OC decomposition rates in surfacial/subsurfacial sediments are estimated.OC concentrations range from 0.26% to 1.8%(wt)in the study area. Significant differences in OC content and in horizontal distribution as well as various trends in surfacial /subsurfacial sediments exhibit the feature of regional difference remarkably in marginal sea sediments. The complicated distribution of OC in surface sediments is due to the influence of bacterial activity and abundance, bioturbation of benthos and physical disturbance. The OC decomposition rate constant in surfacial /subsurfacial sediments ranges from 0.009 7 to 0.076 a-1 and the relatively high values may be mainly related to bacteria that are mainly responsible for OC mineralization;meio-and macrofauna affect OC degradation both directly, through feeding on it, and indirectly through bioturbation and at the same time coarse sediments are also disadvantageous to OC preservation.In almost all the middle and bottom sediments the contents of OC decrease with the increase of deposition depth, which indicates that mineralization of OC in the middle and bottom sediments has occurred via processes like SO reduction and Fe-oxide reduction.

Estimation of Ecological Water Requirements Based on Habitat Response to Water Level in Huanghe River Delta,China

In recent years,wetland ecological water requirements (EWRs) have been estimated by using hydrological and functional approaches,but those approaches have not yet been integrated for a whole ecosystem.This paper presents a new method for calculating wetland EWRs,which is based on the response of habitats to water level,and determines water level threshold through the functional integrity of habitats.Results show that in the Huanghe (Yellow) River Delta water levels between 5.0 m and 5.5 m are required to maintain the functional integrity of the wetland at a value higher than 0.7.One of the dominant plants in the delta,Phragmites australis,tolerates water level fluctuation of about ± 0.25 m without the change in wetland functional integrity.The minimum,optimum and maximum EWRs for the Huanghe River Delta are 9.42×106 m3,15.56×106 m3 and 24.12×106 m3 with water levels of 5.0 m,5.2 m and 5.5 m,corresponding to functional integrity indices of 0.70,0.84 and 0.72,respectively.A wetland restoration program has been performed,which aims to meet these EWRs in attempt to recover from losses of up to 98% in the delta's former wetland area.

RELATIONSHIP BETWEEN DEVELOPMENTS OF THE HUANGHE AND YONGDING RIVERS AND THE EVOLUTION OF THE FOSSIL LAKES OF THE CENOZOIC ERA IN THE DRAINAGE AREA

The Huanghe and Yongding rivers were formed before the early and middle Pliocene epoch. Then they became interior rivers because of the appearance of interior fault lake basins at the end of the Pliocene epoch. The interior flow period continued until the end of the early Pleistocene or the middle pf the Middle Pleistocene, and then they changed into the exterior rivers again till today.

Assessing the benthic habitat quality in the Huanghe(Yellow River) Estuary and its adjacent areas using AMBI and M-AMBI

The protection of the biological diversity and the maintenance of the regional ecological integrity for the Huanghe （Yellow River） Estuary and its adjacent areas are practically significant and valuable. However, frequent human activities and natural climate changes have caused vigorous disturbances on the ecosystem in these sea areas. An objective assessment on the benthic habitat quality （BHQ） of the Huanghe Estuary and its adjacent areas is conducted, using AZTI＇s Marine Biotic Index （AMBI） and multivariate AMBI （M-AMBI） based on the data of macrobenthos in May and August 2011. The results show that both the indices do not correlate significantly, and their assessment results are greatly different. All of the samples assessed using the AMBI were ＂high＂ or ＂good＂, because the ecological group I （EGI） and the ecological group II （EGII） were dominant macrobenthic ecological groups in the research area. Owing to a low species＇ richness and a high individual abundance in some samples, the BHQ levels using the M-AMBI were worse than those of the AMBI. Significant correlations are observed between the M-AMBI, water depth, bottom water salinity and dissolved inorganic nitrogen, thus the M-AMBI could sensitively respond to environmental changes and distinguish influences from uninfluenced stations, but the AMBI could not. The consistent results between the AMBI and the M-AMBI mainly appeared in the uninfluenced （undisturbed or slightly disturbed） sta- tions. Therefore, the M-AMBI is more effective than the AMBI in assessing the benthic habitat quality in the Huanghe Estuary and its adjacent areas. Using the M-AMBI to assess the BHQ of the Huanghe Estuary and its adjacent areas, the results show that 3% of the stations are undisturbed and the BHQs are ＂high＂, and 61% of the stations are slightly disturbed and those of the BHQ are ＂good＂, and the rest are meanly disturbed and those of the BHQ are ＂moderate＂.

Spatial-temporal changes of tidal flats in the Huanghe River Delta using Landsat TM/ETM+ images

Integrating remote sensing, geographic information system (GIS) and fractal theory, change characteristics of tidal flats and tidal creeks in the Huanghe (Yellow) River Delta over the period of 1986-2001 were discussed. The results show that evolutions of tidal flats throughout the Huanghe River Delta are influenced by various factors, and that progressive succession and regression of tidal flats concur in different coastal segments of the delta. Human activities have played an increasingly important role in the succession process of tidal flats. Due to land reclamation in coastal zones of the delta in the last 15 years, lots of tidal flats were occupied, the artificial coastline migrated seaward (the maximum change rate was 0.8 kmyr-1) and tidal creeks became sparser (the highest decreasing rate of length of tidal creeks was 14.9 kmyr-1). Except for two coastal segments from the Tiaohe Estuary to the 106 Station and from the south of the Huanghe River mouth to the north of the Xiaodao River Estuary, fractal dimension values of tidal creeks in the remaining coastal segments of the delta decreased. In addition, the time dimension, sediment fluxes into the sea, waves and tidal-currents have profound influences on the evolution process of tidal flats. Four types of tidal flats-river-dominated tidal flats, tide-dominated tidal flats, wave-dominated tidal flats and man-dominated tidal flats can be identified. Owing to the intensification of human activities in coastal zones of the delta, man-dominated tidal flats have become the main kind of tidal flats.

A comparison of the applicability of the Shannon-Wiener index,AMBI and M-AMBI indices for assessing benthic habitat health in the Huanghe(Yellow River) Estuary and adjacent areas

From a dataset of macrobenthos obtained from 18 cruises from 2004 to 2013 in the Huanghe（Yellow River）Estuary and its adjacent areas,the composition and characteristics of macrobenthos were analyzed,and the applicability of the Shannon-Wiener Index（H′）,AZTI＇s Marine Biotic Index（AMBI） and multivariate AMBI（MAMBI） for assessing benthic habitat quality was compared.The results showed a total of 203 macrobenthos in the study area.The macrobenthos were dominated by polychaetes,followed by mollusks and crustaceans.The macrobenthic ecological groups were dominated by EGI,EGII and EGIII,which respectively accounted for 31.5%,36.0% and 21.2% of the total.There were significant differences between the evaluation results of the three indices.The ecological quality status（EQS） levels given by the AMBI were greater than those given by the H′ and M-AMBI.The AMBI could not reflect the differences between 11 sites but the H′ and M-AMBI could do.Moreover,the three indices responded well to the variations in salinity（S） and dissolved oxygen（DO） in the waters.The H′ and MAMBI also responded sensitively to the differences in physical parameters,such as water depth and sediment texture.The correlation between M-AMBI and environmental pressure gradient data was the strongest.The MAMBI could effectively distinguish degraded conditions from undegraded but the H′ and AMBI could not.Therefore,the M-AMBI reflected benthic habitat health well in the study areas.However,the objectivity of evaluation results of M-AMBI needs further verification by physical,chemical and biological methods.The thresholds also need further discussion.

Modeling of suspended sediment transport with wave-induced longshore current in Huanghe (Yellow) River Delta

A three-dimensional suspended sediment model （SED） developed by the present authors is coupled with the combinatorial model of COHERENS （Luyten et al., 1999） （the three-dimensional coupled hydrodynamical-ecological model for Regional and Shelf Seas） and SWAN （Holthuijsen et al., 2004） （the third generation wave model）. SWAN is regarded as a subroutine of COHERENS and gets time- and space-varying current velocity and surface elevation from COHERENS. COHERENS gets time- and space- varying wave relevant parameters provided by SWAN. Effects of wave on current are applied in bottom shear stress, wave-induced depth-dependent radiation stress and surface drag coefficient calculation. At the same time, the damping function of suspended sediment on turbulence is introduced into COHERENS. So the sediment model SED has feedback on circulation model COHERENS. The SED obtains current associated parameters from COHERENS. Then a coupled hydrodynamic-sediment model COHERENS-SED being able to account for interaction between wave and current is obtained. COHERENS-SED is adopted to simulate three-dimensional suspended sediment transport in the Huanghe River delta. In terms of simulation results, there is obvious difference between top and bottom layer of wave-induced longshore current. The values of time series of sediment concentration gotten by COHERENS-SED have, generally, an accepted agreement extent with measurement. Significant wave heights and wave periods obtained by COHERENS-SED show that wave simulation case with currentts effect can give better agreement extent with measurement than case without current＇s effect. In the meantime, suspended sediment concentration distributing rule obtained by COHERENS-SED is similar to former researches and measurement.

Temporal Variations of Water Discharge and Sediment Load of Huanghe River,China

Based on the data from gauging stations, the changes in water discharge and sediment load of the Huanghe （Yellow） River were analyzed by using the empirical mode decomposition （EMD） method. The results show that the periodic oscillation of water discharge and sediment load of the Huanghe River occurs at the interannual, decadal, and multi-decadal scales, caused by the periodic oscillations of precipitation, and E1 Nifio/Southern Oscillation （ENSO） af- fects water discharge by influencing precipitation distribution and contributes to periodic varations in precipitation and water discharge at interannual timescale. The water discharge and sediment load of the Huanghe River have decreased since the 1960s under the influence of precipitation and huamn activities, and human activities attribute more than precipitation to the reduction in the water discharge and sediment load, furthermore, water abstraction and water-soil conservation practices are the main causes of the decrease in water discharge and sediment load, respectively. The reduction in sediment load has directly impacted on the lower reaches of the Huanghe River and the river delta, causing considerable erosion of the river channel in the lower reaches since the 1970s along with River Delta changing siltation into erosion around 2000.

STUDY ON THE ISOTHERMS OF THE INTERACTION BETWEEN SUSPENDED PARTICLES AND Cu (Ⅱ) IN THE HUANGHE RIVER

The isotherms of the interaction between the suspended particles and Cu 2+ ,and the effects of lysine and asparaginic acid on the isotherms in the Huanghe (Yellow) River were studied by applying the theory and method of interfacial stepwise ion/coordination particle exchange. We obtained a new stepped river isotherm, formed by two curves joined together with a “plateau” in the middle. The adsorption equilibrium constants K 1 and K 2 were calculated by using the isothermal equation of surface stepwise ion exchange. Amino acid in small amount promotes exchange adsorption of the suspended particles with Cu 2+ . The degree of promotive action relates to the isoelectric point of amino acid. The promotive effect of lysine is bigger than that of asparaginic acid.

Impact of the water-sediment regulation and a rainstorm on nutrient transport in the Huanghe River

Dissolved nutrient concentration in the Huanghe （Yellow） River at Lijin was monitored during a water-sediment regulation period and a subsequent rainstorm from 14 June to 19 July, 2005. This study provides detailed information on nutrient concentrations in the Huanghe River during the water-sediment regulation and rainstorm periods, and is of significance for the downstream area of the Huanghe River and the Bohai Sea. The average concentrations of nitrate, nitrite and ammonia were 304.7 μmol/L, 0.19 μmol/L, and 1.10 μmol/L, respectively, while the average concentrations of dissolved inorganic phosphorus （DIP） and dissolved silicate （DSi） were 0.23 gmol/L and 122.9 ktmol/L, respectively. Nutrient concentrations during the water-sediment regulation period were mainly influenced by the dilution effect, floodplain effect and sediment resuspension while dilution and erosion effects were the main factors during the rainstorm. The fluxes of dissolved inorganic nitrogen （DIN）, DIP and DSi during the water-sediment regulation and rainstorm periods accounted for 20.4%, 19.5%, 16.7% and 4.97%, 6.45%, 5.47% of the annual nutrient fluxes, respectively. Discharge was the main factor influencing the fluxes of nutrients during both the water- sediment regulation and the rainstorm periods.

TYPES AND DISTRIBUTION PATTERNS OF MODERN TIDAL CHANNELS ALONG THE HUANGHE RIVER DELTA COAST

There are three major types of tidal channels along the coast of the Huanghe (Yellow) River Delta: tidal inlets, tidal creeks, and tidal channels developed from abandoned river channels. The tidal inlets develop mainly in two areas with weak erosion and barrier islands. The tidal channels formed from abandoned river channels mainly developed in the area of the new delta lobes formed since 1934. Tidal creeks developed in the intertidal zone and distributed along almost all parts of the Huanghe River Delta coast, but their scales and features are different.

Numerical study of three-dimensional wave-induced longshore current's effects on sediment spreading of the Huanghe River mouth

A three-dimensional wave radiation stress is introduced into the hydrodynamic sediment coupled model COHERENS-SED, which has been developed through introducing wave-enhanced bottom shear stress, wave dependent surface drag coefficient, wave-induced surface mixing, SWAN, damping function of sediment on turbulence, sediment model and depth-dependent wave radiation stress to COHERENS. The COHERENS-SED is adopted to study the effects induced by wave-induced three-dimensional longshore current on suspended sediment spreading of the Huanghe River （Yellow River） mouth. Several different cases divided by setting different wave parameters of inputting boundary waves are carried out. The modeling results agree with measurement data. In terms of simulation results, it is easy to know that three-dimensional wave radiation stress plays an obvious role when inputting boundary wave height is stronger than 3 m. Moreover, wave direction also affects the sediment spreading rules of the mouth strongly too.