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Статті в журналах з теми "Sediment transport direction":
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Abrantes, João R. C. B., Nuno E. Simões, João L. M. P. de Lima, and Abelardo A. A. Montenegro. "Two-dimensional (2D) numerical modelling of rainfall induced overland flow, infiltration and soil erosion: comparison with laboratory rainfall-runoff simulations on a two-directional slope soil flume." Journal of Hydrology and Hydromechanics 69, no. 2 (May 21, 2021): 140–50. http://dx.doi.org/10.2478/johh-2021-0003.
Анотація:
Abstract This paper presents a two-dimensional (2D) numerical model of soil erosion and sediment transport resulting from rainfall induced overland flow. It is a spatial and temporal dynamic model combining physical and empirical laws and comprises: i) An overland flow module that solves the two-dimensional unsteady water flow equations on an infiltrating surface; ii) A soil infiltration module that uses a combined Horton-SCS scheme; and iii) A soil erosion and sediment transport module that solves the two-dimensional sediment transport equation, distinguishing between rill erosion, interrill erosion and sediment deposition. The performance of the model was evaluated by comparing its results with observed data from laboratory rainfall-runoff experiments on a two-directional 2.00 × 2.00 m2 soil flume set at 1% and 10% slopes in the x- and y-directions, respectively. The x-direction produced remarkably lower runoff and transported sediments than the y-direction. The numerical model significantly underestimated x-direction lower values of runoff and transported sediments. However, in the y-direction the model presented very good performance. Overall, in total terms (x- plus y-direction), the numerically simulated graphs of runoff and sediment transport were in very good agreement with corresponding experimental measurements, demonstrating the laboratory proof-of-concept of the model.
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Al-Salem, K., and A. Al-Rashed. "Modeling of Sediment Transport Using Wave Height action in Fialaka Marina." IOP Conference Series: Earth and Environmental Science 958, no. 1 (December 1, 2021): 012023. http://dx.doi.org/10.1088/1755-1315/958/1/012023.
Анотація:
Abstract Failaka Island is the second-largest and one of the most important islands of Kuwait from the point of view of tourism located in the north Arabian Gulf. It has a marina constructed in 1979 and managed by the Ministry of Communication (MOC) and a tourism enterprise, and is widely used for its ferry landing facility. The coastal waters around Failaka are turbid and current velocities tend to be as high as ~0.5 m/s during spring tide. The marina basin, with axial plan view dimensions of about 285 m by 260 m experiences shoaling of naturally flocculated fine (cohesive) sediment and coarse sand in the entrance channel and more generally in the southern half of the basin. A particularly noteworthy zone of heavy and visible shoaling is along the inner side of the south breakwater close to the entrance. The marina at Failaka Island is suffering from siltation and sediment deposing issues. This study was carried out numerically to assess the annual sedimentation, sediment direction, and longshore current from locations around the existing marina to help in a suggestion of the solutions to reduce the siltation and sediment deposing based on sediments transport direction on marina entrance. A newly developed numerical solution for annual longshore sediments transport was used to estimate the total sediment transport and its direction. The study shows that the annual sediment transport directions which affect the Fialaka marina entrance are coming from the south to north due to wave action.
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Cheng, Wufeng, Shenliang Chen, Jun Zhu, Xiaojing Zhong, Jin Hu, and Junli Guo. "Identification of the Sediment Movement Mechanism via Grain Size and Shape: A Case Study of a Beach in Eastern Hainan Island in South China." Water 15, no. 20 (October 17, 2023): 3637. http://dx.doi.org/10.3390/w15203637.
Анотація:
This paper used dynamic image analysis (DIA) to analyze the grain size and shape data of beach surface sediments in Bao’ding Bay, eastern Hainan Island, China, and explored the effects of sediment transport modes and beach morphology on the grain size–shape trend curves. This paper adopted a method of combining grain size cumulative frequency curves and grain size–shape trend curves to identify three sediment transport modes: suspension, saltation, and traction, and analyzed the characteristics of the grain size–shape trend curves under different beach morphologies (reflective, intermediate, and dissipative). This paper found that the grain size–shape trend curves can effectively indicate the sediment transport modes and improve the accuracy of subpopulation division; the grain size–shape trend curves showed different distribution characteristics in the cross-shore and longshore directions, which are closely related to the beach’s morphology and sediment transport direction. This paper provides a new method and idea for studying beach sediment transport and sedimentary environment using sediment grain size and shape data.
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ABO ZED, ABO BAKER I. "Effects of waves and currents on the siltation problem of Damietta harbour, Nile Delta coast, Egypt." Mediterranean Marine Science 8, no. 2 (December 3, 2007): 33. http://dx.doi.org/10.12681/mms.152.
Анотація:
This study evaluates the effect of prevailing dynamic factors on the sedimentation process in Damietta Harbour along the Nile delta coast of Egypt. The monitoring program spanned the period between 1978 and 1999 and included measurements of waves, currents and bathymetric profiles. The evaluation was based on determination of erosion and accretion rates, current regime, sediment transport, wave characteristics and wave refraction. Results revealed that the predominant wave direction from N-NW sector (86 %) throughout the year is responsible for generation of a longshore eastward current. Less frequent waves from the N-NE sector generate an opposing longshore westward current. The refraction pattern for the prevailing wave direction indicates that the harbour and its navigation channel are located within a divergence of wave orthogonal and in an accretion sediment sink area. The annual net rate of littoral drift on the western side of the harbour is about 1.43 * 105 m3 (accretion), while the annual net rate of littoral drift on the eastern side is about 2.54 * 105 m3 (erosion). Currents fluctuate tremendously in speed and direction, especially during the winter months. Hence, sediment transport takes place in offshore, eastward, and onshore directions. Progressive vector diagrams show that the largest near bottom offshore, onshore and easterly net drift occurs during summer, spring and winter respectively. The onshore sediment transport generated during spring and summer plays an important role in the redistribution of eroded sediments during the winter. The overall study of dynamic factors indicated that the harbour site is characterized by eastern, western, offshore and onshore sediment movements. Therefore, the north-south orientation of the navigation channel, with its depth greater than the surrounding area, interrupts sediment drift from different directions and reduces the current speed. Consequently, the sediments sink within the navigation channel from different directions. The sources of sediments contributing to the siltation process of the harbour and its navigation channels are mainly derived from the Rosetta promontory, Burullus beaches, Damietta promontory and from offshore and the dumping area.
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Shen, Jian, Dianci Chi, and Bingrou Xi. "Sediment distributions and transport patterns in the Pearl River Estuary and its adjacent coastal ocean." Advances in Engineering Technology Research 8, no. 1 (October 19, 2023): 398. http://dx.doi.org/10.56028/aetr.8.1.398.2023.
Анотація:
Coastal sediment is important for the development of river deltas and for carrying both nutrients and pollutants into estuaries and coasts. Totally 265 surficial sediments collected from the Pearl River Estuary and its adjacent coastal ocean were analyzed by using Gao-Collins method to study the sediment transport path and deposition center. The Pearl River Estuary was an area of sandy mud sediment and showed some muddy patches. There were 5 distinguishable sediment convergence centers, which represent 3 types of sediment transport patterns and hydrodynamic environments. The net sediment transport pathways in the estuary and shelf sea were mainly in the offshore and landward direction, respectively. The analyzed results indicated that the main part of muddy sediment was confined to the mouth of the estuary due to the combined effects of the expansion and salinity intrusion.
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Adel, Mnaf, and Ali N. Hilo. "The Effects of submerged vanes inclination angle on sediment transport into sub-channel." Wasit Journal of Engineering Sciences 11, no. 1 (April 1, 2023): 105–15. http://dx.doi.org/10.31185/ejuow.vol11.iss1.414.
Анотація:
The sub-channels that branch from the larger rivers may be manmade or natural. From the major channels, these sub-channels transfer sediments and water. The deposition of sediments at the entrance, sub-channel is a significant research challenge because it threatens the sub-facilities channel's and reduces the sub-carrying channel's capacity. Therefore, submerged vanes were used to reduce the amount of sediment entering the sub-channel. The goal of the vanes is to reduce the amount of sediment entering the sub-channel, hence redistributing sediment at the sub-entry channel's . They are vertically aligned with the flow direction and tilted at a certain angle. A physical model of the main channel, a sub-channel at a right angle, and a sediment feeder mechanism were developed. 51 tests were undertaken, 3 with submerged vanes and 48 without, with a varying number of submerged vanes (7, 5, 3 and 1). And angling it at various angles (10˚, 20˚, 30˚, and 40˚) in the discharge direction and with three sub-discharges of (19.1, 27 and 30.5 l/s), the sediment concentration flow was (6 kg/h). The weights of the sediments in sub-channel were calculated, and it was found that there is an effective use of these vanes and that the least amount of sediments is achieved when the angle is (20ᵓ). It was observed that the performance of the submerged vanes was significantly improved when there was a decrease in the discharge of the sub-channel.
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Walstra, Dirk-Jan, J. De Vroeg, J. Van Thiel de Vries, C. Swinkels, A. Luijendijk, W. De Boer, R. Hoekstra, et al. "A COMPREHENSIVE SEDIMENT BUDGET FOR THE MISSISSIPPI BARRIER ISLANDS." Coastal Engineering Proceedings 1, no. 33 (October 25, 2012): 81. http://dx.doi.org/10.9753/icce.v33.sediment.81.
Анотація:
In order to conceive any realistic plan for post-Katrina island restoration, it is necessary to understand the physical processes that move sand along the littoral drift zone off the coast of Mississippi. This littoral zone influences the character of the Mississippi barrier islands as they exist in an ever changing cycle. To help in this understanding, a sediment transport model was conducted to establish a current sediment budget for the islands. This study evaluated the existing regional sediment transport magnitudes and directions for the Mississippi and Alabama barrier islands fronting Mississippi Sound including daily conditions and hurricanes. A method was developed to incorporate all relevant hurricanes from 1917 to 2010 in the analysis. For the long term average net longshore transport along the southern shorelines of the barriers (i.e. exposed to the Gulf of Mexico), the contribution of year-averaged conditions and hurricanes are of similar order of magnitude, although the mean annual percentage occurrence of hurricanes is no more than about 3%. Along the northern shores (Mississippi Sound side) the transport is considerably smaller and the contributions of cold fronts and hurricanes to the sediment transports are more or less equal. For the year-averaged conditions (excluding hurricanes) a westward directed net transport is found. The net effect of the historic hurricanes is also westward in direction. However, for individual hurricanes (e.g. Camille and Katrina) the net transport along Ship Island can be directed eastward due to the dominance of ebb flows after the eye of the hurricane had passed.
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Wang, Hongbing, Yuxi Wu, Xiaoming Wan, Lu Xia, and Si Wang. "Grain Size Characteristics of Surface Sediments and Their Migration Trends in the Nearshore Waters of East Guangdong." Sustainability 15, no. 14 (July 15, 2023): 11069. http://dx.doi.org/10.3390/su151411069.
Анотація:
By collecting surface sediment samples from 158 stations in the near-shore waters of eastern Guangdong, grain size analysis and grain size parameter calculations were performed to explore the characteristics and migration trends of surface sediments in the area. The analysis of the grain size results showed that the surface sediments in the nearshore waters of east Guangdong could be classified into nine sediment types, mainly including seven types of gravel sand ((g)S), gravel muddy sand ((g)mS), gravelly mud ((g)M), sand (S), silty sand (zS), sandy silt (sZ) and silt (Z). The relative percentages of gravel, sand, silt and mud were 0.7%, 40.56%, 46.7% and 12.04%, respectively. The average grain size varied from −2φ to 8φ, with an average of 4.94φ. The selection coefficient ranged from 0.44 to 3.78, with an average value of 1.8. The skewness distribution ranged from −0.34 to 0.67, with an average value of 0.07. By extracting and analyzing the spatial distribution information of grain size in the study area, using the Gao–Collins migration trend analysis method and incorporating dynamic factors such as tidal currents and waves, the transport direction and trend of surface sediments in the study area could be analyzed and inferred. The results show that the surface sediment migration trend was significant, migration on the north side of Nan’ao Island was in an east-to-west direction, and the sediment of Yifeng River was mainly deposited to the sand spout at the mouth of Lianyang River. After southward transport from the Houjiang waterway, the migration was mainly southeastward and the trend was quite significant until the 20 m isobath, where the trend gradually decreased. The sediments of the Rongjiang River were mainly deposited outside the mouth of Niutian Yang and Rongjiang River, and the surface sediments of Guang’ao Bay and Haimen Bay migrated in the northwest–southeast direction. After the 30 m isobath, the southeast corner of the study area migrated in the southeast–south direction. This sediment transport pattern revealed by the grain size migration trend is in good agreement with the physical and hydrodynamic conditions of the study area and provides an important reference for decisions regarding port dredging and waterway management in the area.
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Anokhin, V. M., O. M. Vinogradova, I. M. Pyatov, and D. S. Dudakova. "Longshore Sediment Transport in Lake Ladoga Based on Analyses of the Heavy Mineral Fraction of Sand in Coastal Sediments." Известия Русского географического общества 155, no. 3-4 (December 1, 2023): 3–16. http://dx.doi.org/10.31857/s0869607123030023.
Анотація:
Abstract—In order to identify the directions of transport of coastal sediments of Lake Ladoga, heavy mineral fraction was extracted from sand samples collected on all types of its shores. The mineral composition, size and roundness of particles − features characterising the degree of reworking of coastal sediments − were assessed under a microscopic analysis. We identified 4 clusters with similar degrees of reworking of the source material, which, based on the results of the factor analysis, were ranked by relative transport distance from insignificant to very significant. The maximum number of samples with small transport distances was found on the northern shores of the lake, which can be explained by the location of bedrock shores − the main sources of clastic material in the lake. Samples with maximum transport distances are relatively evenly distributed along all shores of the lake. The analysis of the results showed that on all shore reaches there is a transport of heavy fraction of bottom sediments in a certain direction: on the southern shore – to the west, on the western shore – to the north, on the northern shore – to the east and on the eastern shore – to the south-east. This allows us to conclude that there is a long-term trend of coastal sediment transport along the shores of Lake Ladoga in a clockwise direction.
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Rachman, Cyril, and Yuyun Qomariyah. "INVESTIGATING THE LITTORAL TRANSPORT OF SEDIMENT ALONG THE NASESE COASTLINE, SUVA, FIJI ISLANDS." Coastal Engineering Proceedings, no. 36v (December 28, 2020): 48. http://dx.doi.org/10.9753/icce.v36v.sediment.48.
Анотація:
The research investigated the current Nasese Coastline area from the impact of Littoral transport, a term used for the transport of non-cohesive sediments, i.e. mainly sand, along the foreshore and the shoreface of Nasese due to the action of the breaking waves and the longshore current. The littoral transport is also called the longshore transport or the littoral drift. The theoretical concept coastal sediment properties can be used to evaluate properties of sediment on site to avoid serve impacts towards the Suva Port in the future. The method used was on-site measurement by surveying to generate coastal profiles. Along with this, 1464 hours of wind data for the months of November and December 2019 were used to generate the frequency of the magnitude of Wind and the Direction using Wind Rose Plots for Meteorological Data. The movement of the sediments through the Beach Profiles agrees with the output generated Wind Directions. Therefore, Suva Port, may consider this situation in terms of the routine maintenance of dredging in order to sustain the acceptable depth of the Sea Port.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/vW05xoiNa_w
Дисертації з теми "Sediment transport direction":
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Baville, Paul. "Stratigraphic correlation uncertainty : On the impact of the sediment transport direction in computer-assisted multi-well correlation." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0111.
Анотація:
La modélisation du sous-sol est un moyen de prédire la structure et la connectivité des unités stratigraphiques en honorant les observations de subsurface. Ces observations sont en général échantillonées le long de puits à grande échelle horizontale (kilomètre) mais à petite échelle verticale (mètre). Il y a deux types de données de puits : (1) les diagraphies, qui correspondent à des acquisitions géophysiques quasi-continus (échatillonage régulier) le long du puits (e.g., gamma ray, sonic, porosité neutron), et (2) les régions, qui correspondent à des propriétés réservoir discrètes définies par des profondeurs maximales et minimales le long du puits (e.g., biozones, zones structurales, faciès sédimentaires). Des marqueurs sont interprétés le long des puits et peuvent être associés pour générer un ensemble d'associations de marqueurs conformes, appelé des corrélations de puits. Ces corrélations de puits peuvent être réalisées manuellement (approche déterministe) par des experts, mais cela peut être sujet à des biais et ne garantit pas la reproductibilité. Les corrélations de puits peuvent également être générées automatiquement (approche déterministe ou probabiliste) en calculant à l'aide d'un algorithme un grand nombre de corrélations de puits conformes et en classant ces réalisations en fonction de leurs vraisemblances. La vraisemblance de ces corrélations de puits assistées par ordinateur est directement liée au principe de corrélation utilisé pour associer les marqueurs. Ces travaux de thèse introduisent deux principes de corrélation, qui tendent à reproduire la chronostratigraphie et les processus de dépôts à l'échelle de la paraséquence : (1) "un marqueur (décrit par un faciès et une distalité pris au centre d'un intervalle ayant un faciès constant et une distalité constante) ne peut pas être associé avec un autre marqueur décrit par un faciès plus profond à une position plus proximale, ou un faciès moins profond à une position plus distale", et (2) "plus la différence entre une interpolation chronostratigraphique (entre les marqueurs) et un profil de dépôt conceptuel est faible, plus la probabilité d'association des marqueurs est élevée". Ces deux principes de corrélation sont d'abord validés avec des solutions analytiques et appliqués sur des cas synthétiques. Ils ont ensuite été utilisés (1) pour prédire la connectivité des unités stratigraphiques à partir de données de puits sans connaissances solides sur les environnements de dépôt en inférant les paramètres de corrélation, ou (2) pour évaluer la probabilité d'un environnement de dépôt hypothétique en générant des réalisations stochastiques et en évaluant les incertitudes. Les methodes sont appliquées sur un système silicoclastique de dépôts deltaïques côtiers ciblant un réservoir du Jurassique Moyen dans le South Viking Graben en Mer du Nord. Ces travaux de thèse permettent (1) de définir deux principes de corrélation spécifiques définis par quelques paramètres qui peuvent être utilisés pour générer des corrélations de puits stochastiques dans les systèmes deltaïques côtiers, et (2) d'ouvrir la voie vers une combinaison simple de principes de corrélation spécifiques pour obtenir une meilleure caractérisation des systèmes deltaïques côtiers en évaluant les incertitudesSubsurface modeling is a way to predict the structure and the connectivity of stratigraphic units by honoring subsurface observations. These observations are commonly be sampled along wells at a large and sparse horizontal scale (kilometer-scale) but at a fine vertical scale (meter-scale). There are two types of well data: (1) well logs, corresponding to quasi-continuous (regular sampling) geophysical measurements along the well path (e.g., gamma ray, sonic, neutron porosity), and (2) regions, corresponding to categorical reservoir properties and defined by their top and bottom depths along the well path (e.g., biozones, structural zones, sedimentary facies). Markers are interpreted along the well path and can be associated in order to generate a consistent set of marker associations called well correlations. These well correlations may be generated manually (deterministic approach) by experts, but this may be prone to biases and does not ensure reproducibility. Well correlations may also be generated automatically (deterministic or probabilistic approach) by computing with an algorithm a large number of consistent well correlations and by ranking these realizations according to their likelihood. The likelihood of these computer-assisted well correlations are directly linked to the principle of correlation used to associate markers. This work introduces two principles of correlation, which tend to reproduce the chronostratigraphy and the depositional processes at the parasequence scale: (1) "a marker (described by facies and distality taken at the center of an interval having a constant facies and a constant distality) cannot be associated with another marker described by a depositionally deeper facies at a more proximal position, or a depositionally shallower facies at a more distal position", and (2) "the lower the difference between a chronostratigraphic interpolation (in between markers) and a conceptual depositional profile, the higher the likelihood of the marker association". These two principles of correlation are first benchmarked with analytical solutions and applied on synthetic cases. They have then been used (1) to predict the connectivity of stratigraphic units from well data without strong knowledge on depositional environments by inferring the correlation parameters, or (2) to evaluate the likelihood of a hypothetical depositional environment by generating stochastic realizations and assessing the uncertainties. The methods are applied on a siliciclastic coastal deltaic system targeting a Middle Jurassic reservoir in the South Viking Graben in the North Sea.This work enables (1) to define two specific principles of correlation defined by a few parameters that can be used to generate stochastically well correlations within coastal deltaic systems, and (2) to open the path towards a simple combination of specific principles of correlation to obtain a better characterization of coastal deltaic systems by assessing the uncertainties
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van, Gaalen Joseph F. "Longshore Sediment Transport From Northern Maine To Tampa Bay, Florida: A Comparison Of Longshore Field Studies To Relative Potential Sediment Transport Rates Derived From Wave Information Study Hindcast Data." Scholar Commons, 2004. https://scholarcommons.usf.edu/etd/1280.
Анотація:
This paper examines the regional longshore sediment transport pattern of the seaward coast of the United States and Gulf of Mexico from northern Maine to Tampa Bay, Florida. From previous studies it is known that along the coast there are variations in direction of sediment transport known as nodal zones as well as variations in sediment transport rate. Wave Information Study (WIS) hindcast data for the interval 1976 through 1995 (United States Army Corps of Engineers, 2003) provide a spatially continuous model of the regional longshore current directions in the study area.
In chapter one, all available published field studies of longshore current direction and sediment transport directions and rates are compiled to create a description of the direction and, whenever possible, magnitude of longshore transport. A detailed compilation of regional and local published studies are provided in tables. An interpretation of sediment transport rates and directions is provided in eight regional maps of the study area.
In chapter two the results of the literature compilations are compared with gross and net potential sediment transport directions and rates modeled using WIS hindcast data. The WIS deep-water wave characteristics are used to predict the directions and rate of longshore sediment transport at local outer coast positions using the method of Ashton et al. (2003a). The WIS-derived transport directions, including nodal zones, generally agree with the published field studies, although there are a few local inconsistencies particularly near inlets, shoals and irregular bathymetry. Trends in longshore transport rates, such as increases and decreases in gross transport rates are well represented by the WIS-derived potential transport rates. The discrepencies between the published field studies and WIS results are apparently primarily due to assumptions in the WIS model, such as assuming shore-parallel bathymetric contours.
3
Xu, Tongtong. "Wave transformation and alongshore sediment transport due to obliquely oriented shoreface-connected ridges." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54466.
Анотація:
The inner continental shelf off the western half of the barrier island Fire Island, NY, is characterized by a series of obliquely oriented shoreface-connected ridges. The long-term historic shoreline record shows persistent undulations in shoreline shape at an alongshore scale similar to the alongshore scale of the ridges. This suggests that the ridges affect the wave transformation, alongshore sediment transport and corresponding shoreline change. These processes are investigated by utilizing the SWAN (Simulating WAves Nearshore) model, forced with realistic wave parameters, on a simplified, synthetic bathymetry replicating the scales of the shoreface-connected ridges. Results indicate that the relative magnitude of alongshore variations of modeled waves, alongshore transport, and the corresponding shoreline change are highly correlated with the relative orientation of the incoming waves to the ridges. Alongshore variations in both wave height and direction along the breaker line are much stronger when the predominant wave direction is along the main axis of the ridges rather than perpendicular to the ridge crests. This pattern of wave height variation is further explained by evaluating the directional energy spectrum and using a reverse ray-tracing technique. The gradients of the alongshore sediment transport, which lead to shoreline change, also appear to be stronger for waves with an angle of incidence similar to the ridge orientation. These results help explain the relationship between the oblique shoreface-connected ridges and the corresponding shoreline changes and shed light on the connection between the inner-shelf ridges and persistent shoreline undulations for the Western portion of Fire Island.
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Vilches, Thanira Thammy Bastos. "Relação entre reflectâncias de imagens orbitais e transporte de sedimentos em suspensão no Rio Doce." Universidade Federal do Espírito Santo, 2013. http://repositorio.ufes.br/handle/10/6134.
Анотація:
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Previous issue date: 2013-03-11Suspended solids transport excess, caused by erosion, may limit water use and cause rivers siltation. Suspended solids concentration may be assessed by remote sensing because the reflectance of the scenes, in the visible and infrared ranges, is positively influenced. This work aims at the understanding of the variability of suspended sediments concentrations in a Doce river stretch located in Espírito Santo state, Brazil, through spectral analysis of satellite images data and analysis of field measurements results. There were analyzed suspended solids concentrations for samples collected in Regência and Colatina Doce river sections and images captured by LANDSAT 5 TM satellite. To obtain reflectance values, the following operations were performed: geometric correction, conversion of DN values to apparent FRB values, atmospheric correction, using the 6S model (FRB surface), and transformation of NCs values.The results showed that, for the images corrected from atmospheric effects, the values of the ND curve related to the apparent FRB are higher than the values of the surface s FRB curve in the visible region, due to the electromagnetic radiation scattering phenomenon. In the near-infrared regions, the reverse was observed, because of the absorption of electromagnetic radiation by the atmosphere. It was observed positive correlation between reflectance and suspended solids concentration, despite the difficulties in obtaining data from same satellite images and field sample collection dates. For Regência data, the best correlation was obtained for band 1, located in the visible range of the surface s FRB curve, suggesting less suspended sediment transport. For Colatina, the best correlation occurred for band 4, located in the near-infrared range of the same surface s FRB curve, indicating greater sediment transport in this part of the Doce river during the sampling dates. It was concluded that the surface reflectance best represents the water spectral curve and that the correlated data showed the following pattern: smaller reflectance corresponds to lower water suspended solids concentration
O transporte de sólidos em suspensão, causado por erosão, é um dos problemas que limitam o uso da água, podendo causar assoreamento nos rios. A concentração de sólidos suspensos pode ser avaliada através do sensoriamento remoto, pois a reflectância da cena, na faixa do visível e do infravermelho, é positivamente influenciada. Desta forma, este trabalho visa o conhecimento da variabilidade das concentrações de sedimentos em suspensão no trecho do rio Doce localizada no ES, através de análises de dados espectrais contidos nas imagens orbitais e de resultados de medições em campo. Para tanto, foram avaliados dados concentrações de sólidos suspensos em amostras coletadas em Regência e Colatina, e imagens TM do satélite LANDSAT 5. Para obtenção dos valores de reflectância, foram realizadas as seguintes operações: correção geométrica, conversão dos NDs para valores de FRB aparente, correção atmosférica com uso do modelo 6S (FRB superfície), e transformação de NCs em valores de reflectância. Os resultados mostraram que nas imagens corrigidas dos efeitos atmosféricos, os valores da curva de ND referentes aos FRBs aparentes são superiores aos valores da curva FRB de superfície na região do visível, devido ao fenômeno de espalhamento da radiação eletromagnética. Nas regiões do infravermelho próximo, ocorreu o inverso, uma vez que há absorção da radiação eletromagnética pela atmosfera. Quanto aos sólidos suspensos, foram encontradas correlações positivas entre a reflectância e a concentração dos sólidos suspensos, apesar das dificuldades de obtenção de dados concomitantes das datas de imagens orbitais com datas da coleta de campo. Para os dados de Regência, a melhor correlação ocorreu para banda 1, que se localiza na faixa do visível, da curva dos FRB de superfície, sugerindo menor transporte de sedimentos suspensos. Para Colatina, ocorreu para banda 4, que se encontra na faixa do infravermelho próximo, também para curva dos FRB de superfície, sugerindo maior transporte de sedimentos nesse trecho do rio Doce, para as datas de amostragem. Conclui-se que a reflectância que melhor representa a curva espectral da água é de superfície e os dados correlacionados seguiram o padrão de quanto menores as reflectâncias, menores as concentrações de sólidos suspensos na água
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Heald, J., I. K. McEwan, and Simon J. Tait. "Sediment transport over a flat bed in a uni-directional flow: simulations and validation." 2004. http://hdl.handle.net/10454/3619.
Анотація:
NoA discrete particle model is described which simulates bedload transport over a flat bed of a unimodal mixed-sized distribution of particles. Simple physical rules are applied to large numbers of discrete sediment grains moving within a unidirectional flow. The modelling assumptions and main algorithms of the bedload transport model are presented and discussed. Sediment particles are represented by smooth spheres, which move under the drag forces of a simulated fluid flow. Bedload mass-transport rates calculated by the model exhibit a low sensitivity to chosen model parameters. Comparisons of the calculated mass-transport rates with well-established empirical relationships are good, strongly suggesting that the discrete particle model has captured the essential elements of the system physics. This performance provides strong justification for future interrogation of the model to investigate details of the small-scale constituent processes which have hitherto been outside the reach of previous experimental and modelling investigations.
Книги з теми "Sediment transport direction":
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Passchier, Sandra. Sediment supply and transport directions in the Gulf of Gdańsk as observed from SEM analysis of quartz grain surface textures =: Geneza osadów dennych i źródła materiału osadowego w Zatoce Gdańskiej w świetle analizy SEM powierzchni ziarn kwarcu. Warszawa: Polish Geological Institute, 1997.
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Mofjeld, Harold O. Formulas for velocity, sediment concentration and suspended sediment flux for steady uni-directional pressure-driven flow. Seattle, Wash: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Pacific Marine Environmental Laboratory, 1988.
Частини книг з теми "Sediment transport direction":
1
Kawamura, Kiichiro, Kazumasa Oguri, Mutsuo Inoue, Kan-Hsi Hsiung, Taishi Kudaka, and Ken Takai. "Ongoing Persistent Slope Failures at the Toe of a Giant Submarine Slide in the Ryukyu Trench that Generated the AD 1771 Meiwa Tsunami." In Progress in Landslide Research and Technology, Volume 1 Issue 2, 2022, 63–74. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-18471-0_5.
Анотація:
AbstractThis study investigates sedimentation processes and associated submarine sliding on the floor of the Ryukyu Trench. Three dive surveys were conducted using the manned submersible Shinkai 6500 (hereafter 6K) in the trench. The AD 1771 Meiwa tsunami was generated by a giant submarine slide on the landward trench slope in this region. Dive survey site 6K#1469 was located on a mouth of the submarine canyon in the forearc basin. Dive survey site 6K#1468 was located on the uppermost part of the submarine slide, where steps and fissures were observed. Dive survey site 6K#1467 was located at the toe of the submarine slide, which is covered by a muddy sediment layer. Core sample 6K#1467 measured 36.3 cm long and comprised muddy sediments interlayered with silt and/or sand laminations. The paleocurrent direction of the laminated sediments is mostly from north to south, indicating that they were not transported along with the trench but were from the landward slope, probably via repeated small submarine slides. The sedimentation rate for sample 6K#1467 was estimated at 2.42 mm/year using a depth profile of 210Pbex concentration within 10 cm deep and a date for the sediment of ~ 50 year ago. Based on the sedimentation rate and the number of laminae, the typical recurrence interval of the silt/sand layers is calculated to be ~ 6 year. We interpret these results as indicating that repeated small submarine slides have occurred persistently (recurrence interval of ~ 6 year) at the toe of the investigated giant submarine slide in the Ryukyu Trench over the last 50 year.
2
Yang, Shu-Qing. "Formulae of Sediment Transport in Unsteady Flows (Part 2)." In Sediment Transport - Recent Advances [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94761.
Анотація:
Sediment transport (ST) in unsteady flows is a complex phenomenon that the existing formulae are often invalid to predict. Almost all existing ST formulae assume that sediment transport can be fully determined by parameters in streamwise direction without parameters in vertical direction. Different from this assumption, this paper highlights the importance of vertical motion and the vertical velocity is suggested to represent the vertical motion. A connection between unsteadiness and vertical velocity is established. New formulae in unsteady flows have been developed from inception of sediment motion, sediment discharge to suspension’s Rouse number. It is found that upward vertical velocity plays an important role for sediment transport, its temporal and spatial alternations are responsible for the phase lag phenomenon and bedform formation. Reasonable agreement between the measured and the proposed conceptual model was achieved.
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Bianchi, Thomas S. "Sources and Distribution of Sediments." In Biogeochemistry of Estuaries. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195160826.003.0014.
Анотація:
The uplift of rocks above sea level on the Earth’s surface over geological time, produces rock material that can be altered into soils and sediments by weathering processes. Over geological time, a fraction of sediments can be sequestered for storage in the ocean basins—with most of it stored in the coastal margin. However, much of this material is modified via processing in large river estuarine systems which can ultimately affect the long-term fate of these terrigenous materials. Sediments produced from weathering of igneous, metamorphic, and sedimentary rocks are principally transported to the oceans through river systems of the world. The major routes of sediment transport from land to the open ocean can simply be illustrated through the following sequence: streams, rivers, estuaries, shallow coastal waters, canyons, and the abyssal ocean. It should be noted that significant and long-term storage occurs in river valleys and floodplains (Meade, 1996). Submarine canyons are also thought to be temporary storage sites for land-derived sediments; however, episodic events such as turbidity currents and mud slides can move these sediments from canyons to the abyssal ocean (more details on coastal margin transport to the deep ocean are provided in chapter 16). The annual sediment flux from rivers to the global ocean is estimated to range from 18 to 24 × 109 metric tonnes (Milliman and Syvitski, 1992). Conversely, estuaries will eventually fill-in with fluvial inputs of sediments over time, and ultimately reach an equilibrium whereby export and import of sediment supply are balanced (Meade, 1969). For example, recent studies have shown that sediment accumulation in the Hudson River estuary, both short (Olsen et al., 1978) and long term (Peteet and Wong, 2000), is in equilibrium with sea level rise. More specifically, it is believed that river flow controls the direction of sediment flux in the Hudson, while variations in spring-neap tidal amplitude control the magnitude (Geyer et al., 2001). Weathering is typically separated into two categories: physical and chemical. Physical weathering involves the fragmentation of parent rock materials and minerals through processes such as freezing, thawing, heating, cooling, and bioturbation (e.g., endolithic algae, fungi, plant roots, and earthworms).
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Uda, Takaaki, Susumu Onaka, and Tomohiro Mori. "Beach Changes Triggered by Ground Subsidence and Waves Generated by Easterly Trade Wind near Pekalongan on North Shore of Java Island." In Sediment Transport Research - Further Recent Advances [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1004907.
Анотація:
The shoreline recession caused by ground subsidence due to the excessive pumping of underground water and that caused by wind waves incident from the easterly direction under the tropical monsoon weather was investigated, taking the Pekalongan area on Java Island as a study area. The study area was divided into nine subareas on both sides of the Comal River delta, and the shoreline changes in each subarea were investigated using satellite images. Field observation was also carried out on August 10, 2022, in the Pekalongan area, and the height of ground subsidence was measured together with the observation of the inundated area using a UAV. It was found that, in this area, the height of ground subsidence reached approximately 1.6 m, and the sinking area has been rapidly expanding. In this area, predominant waves are constantly incident from the easterly direction under the tropical trade wind condition, and in some cases, waves are obliquely incident at a significantly large angle relative to the direction normal to the shoreline. Along the east coast of the Comal River mouth, the mean wave incidence angle was as large as 22° clockwise, whereas on the west side, the angle increased up to 42°, causing marked shoreline changes due to high-angle wave instability.
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Kroon, Aart. "Marine and Coastal Environments." In The Physical Geography of Western Europe. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780199277759.003.0016.
Анотація:
The present coastline of western Europe is shaped by physical processes such as wind, waves, and tidal currents, which cause the marine and coastal sediment transport. Spatial gradients in sediment transport rates induce the morphological adaptation, reflected by either an accumulation or erosion of material. All mutual interactions between these physical processes, and the resultant gradients in sediment transport together with the morphological adaptations, constitute the coastal morphodynamics. The specific initial stage of the morphology and the availability of sediment influence the direction of the morphological adaptation, whereas the rate of the morphological adaptation mostly depends on the energy input into the system. Chemical processes are of less importance in coastal environments of the high to mid-latitudes. Here most geochemical reactions are far too slow to influence the coastal morphology. However, biological processes sometimes play an important role. For example, flocculation of fine sediments by algae in estuaries (Ten Brinke 1993) or filtering by salt-marsh vegetation (Houwing 2000a, b) both positively influence the sediment accumulation rates. The long-term boundary conditions upon which the physical processes act are often determined by geology. The nature of the drainage basin that delivers fresh water and sediments into coastal waters and the nature of the shoreline can be considered as static boundary conditions for short-term morphodynamics. Tectonic forces and global sea-level rise are typical long-term geophysical forces. They will slowly change these boundary conditions, but they hardly influence the short-term adaptations of the morphology. The western European shelf fringes a series of integrated coastal environments that vary from coastal dunes and sandy beaches to estuaries and tidal basins and to sea cliffs and shore platforms. In this chapter a general description of the location and dimensions of the shores of western Europe is presented, followed by a brief summary of its geological history. The geology is focused on present-day deposits, the local lithology with sinks and sources of sediments, and with reference to some geophysical processes such as the relative sea-level rise. Thereafter, the actual coastal processes are discussed.
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Sakhvadze, David, Gigo Jandieri, Besik Saralidze, and Giorgi Sakhvadze. "A novel method of hydro-vacuum dispersion of metallurgical melts: research and implementation." In Sediment Transport Research - Further Recent Advances [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1004129.
Анотація:
In parallel with the gradual expansion of the consumption of powder materials and the increasing demands placed on them, the competition between the producers of powders is continually intensifying. There is no doubt that the future belongs to technologies that provide high productivity and low-cost powders. Consequently, the technology and techniques of powder production need constant revision and modernization. For this goal we have developed and proposed a new method and installation for hydro-vacuum dispersion of melts, the essence of innovation and advantage of which lies in sucking and dispersing the melt in the direction opposite to the action of the force of gravity, under gravity overload 150-200g conditions, where the main work is performed by hydraulic rarefaction resulting from a sharp refraction of direction (on 162-degree angle) and rapid expansion (х10) of a high-pressure water annular flow, with the superimposition of spatial shock- pulsating waves generated in the outer shell of the formed cone-shaped vortex. The device is characterized by high production and low energy costs, while powders - by increased specific surface, improved purity and high activity. The enhanced activity of our powders is due to the formation of non-equilibrium mechanoactivation structural-deformation stresses in them, which leads to the accumulation of excess chemical energy in them. It is justified that the application of the method is also highly effective for dispersing slag melts and obtaining amorphous hardened powdery raw materials with high hydraulic activity, suitable for the production of construction cement. Appropriate recommendations for the industrial implementation of the developed innovative technology have been proposed.
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"Anadromous Sturgeons: Habitats, Threats, and Management." In Anadromous Sturgeons: Habitats, Threats, and Management, edited by Pierre Nellis, Simon Senneville, Jean Munro, Georges Drapeau, Daniel Hatin, Gaston Desrosiers, and François J. Saucier. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569919.ch12.
Анотація:
<em>Abstract.</em>—The short- and long-term impacts of the annual disposal of dredged sediment within Atlantic sturgeon <em>Acipenser oxyrinchus</em> habitat in the St. Lawrence estuary were assessed by simulating sediment transport over 10 years and by sampling sediment and macrobenthos on impacted and control radials. The model applied bed load transport functions embedded in a baroclinic hydrodynamic model. The path predicted by the model was validated at its half-way point (5 years) using multibeam sonar images of the seabed as well as qualitative and quantitative sediment analyses. Sediment took more than 1 year to completely clear the disposal site, indicating continuous sand drift along the predicted path. In the first 2 years, the sediment path increased rapidly in length (10 km), bypassing a field of sand dunes and following the deepest depressions (10 m) in the downstream direction. In the middle of its 10-year course (ca 12 km), the sediment track crossed the most important core area used by early juvenile Atlantic sturgeon. Afterward, sediment progression slowed and accumulated in a 15-mdeep channel between islands in the middle of the estuarine transition zone. The impact stations showed a significant reduction in the average biomass of tubificids, the most important food item of juvenile Atlantic sturgeon in the St. Lawrence. Conversely, the number and abundance of epi- and suprabenthic taxa increased. Model and field results suggest that sand drift generated from disposal operations reduces benthic productivity along the modeled path, including critical habitats of early juvenile Atlantic sturgeon. Sand accumulation from dredged spoil that drift in dead current areas are also likely to reduce juvenile sturgeon habitat quality.
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Armentrout, John M. "Tectonics and paleogeography of a post-accretionary forearc basin, Coos Bay area, SW Oregon, USA." In From Terranes to Terrains: Geologic Field Guides on the Construction and Destruction of the Pacific Northwest, 187–243. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.0062(06).
Анотація:
ABSTRACT This field guide reviews 19 sites providing insight to four Cenozoic deformational phases of the Cascadia forearc basin that onlaps Siletzia, an oceanic basaltic terrane accreted onto the North American plate at 51–49 Ma. The field stops visit disrupted slope facies, prodelta-slope channel complexes, shoreface successions, and highly fossiliferous estuarine sandstones. New detrital zircon U-Pb age calibration of the Cenozoic formations in the Coos Bay area and the Tyee basin at-large, affirm most previous biostratigraphic correlations and support that some of the upper-middle Eocene to Oligocene strata of the Coos Bay stratigraphic record represents what was differentially eroded off the Coast Range crest during ca. 30–25 Ma and younger deformations. This suggests that the strata along Cape Arago are a western “remnant” of the Paleogene Tyee basin. Zircon ages and biostratigraphic data encourages the extension of the Paleogene Coos Bay and Tyee forearc basin westward beyond the Fulmar fault and offshore Pan American and Fulmar wells. Integration of outcrop paleocurrents with anisotropy of magnetic susceptibility data from the middle Eocene Coaledo Formation affirms south-southeast to north-northwest sediment transport in current geographic orientation. Preliminary detrital remanent magnetism data show antipodal directions that are rotated clockwise with respect to the expected Eocene field direction. The data suggest the Eocene paleo-shoreline was relatively north-south similar to the modern shoreline, and that middle Eocene sediment transport was to the west in the area of present-day Coos Bay. A new hypothesis is reviewed that links the geographic isolation of the Coos Bay area from rivers draining the ancestral Cascades arc to the onset of uplift of the southern Oregon Coast Range during the late Oligocene to early Miocene.
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Trenhaile, A. S. "Tide-Dominated Environments." In Coastal Dynamics and Landforms, 190–211. Oxford University PressOxford, 1997. http://dx.doi.org/10.1093/oso/9780198233534.003.0008.
Анотація:
Abstract Tidal currents transport large amounts of sediment within the shallow water regions of the world. Ebb and flood currents move in opposing directions, but they often travel along different paths, and because shallow water tides are asymmetrical, there are marked differences in their duration and in the magnitude and occurrence of their peak flows (Chapter 7). Net sediment transport also occurs when tidal currents combine with local, wind-driven currents, flow from rivers, and normal oceanic circulation. In some areas, rotation of the tides adds a longshore component to the simple onshore-offshore movement of sediment.
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Welch, J. L., B. Z. Foreman, D. Malone, and J. Craddock. "Provenance of early Paleogene strata in the Bighorn Basin (Wyoming, USA): Implications for Laramide tectonism and basin-scale stratigraphic patterns." In Tectonic Evolution of the Sevier-Laramide Hinterland, Thrust Belt, and Foreland, and Postorogenic Slab Rollback (180–20 Ma). Geological Society of America, 2022. http://dx.doi.org/10.1130/2022.2555(09).
Анотація:
ABSTRACT The Bighorn Basin (Wyoming, USA) contains some of the most extensively exposed and studied nonmarine early Paleogene strata in the world. Over a century of research has produced a highly resolved record of early Paleogene terrestrial climatic and biotic change as well as extensive documentation of spatiotemporal variability in basin-scale stratigraphy. The basin also offers the opportunity to integrate these data with the uplift and erosional history of the adjacent Laramide ranges. Herein, we provide a comprehensive provenance analysis of the early Paleogene Fort Union and Willwood Formations in the Bighorn Basin from paleocurrent measurements (n > 550 measurements), sandstone compositions (n = 76 thin sections), and U-Pb detrital zircon geochronology (n = 2631 new and compiled age determinations) obtained from fluvial sand bodies distributed widely across the basin. Broadly, we observed data consistent with (1) erosion of Mesozoic strata from the Bighorn and Owl Creek Mountains and transport into the eastern and southern basin; (2) erosion of Paleozoic sedimentary cover and crystalline basement from the Beartooth Mountains eastward into the northern Bighorn Basin; (3) conglomeratic fluxes of sediment from the Teton Range or Sevier fold-and-thrust belt to the southwestern Bighorn Basin; and (4) potential sediment provision to the basin via the Absaroka Basin that was ultimately derived from more distal sources in the Tobacco Root Mountains and Madison Range. Similar to previous studies, we found evidence for a system of transverse rivers contributing water and sediment to an axial river system that drained north into southern Montana during both the Paleocene and Eocene. Within our paleodrainage and provenance reconstruction, the basin-scale patterns in stratigraphy within the Fort Union and Willwood Formations appear to have been largely driven by catchment size and the lithologies eroded from the associated highlands. Mudrock-dominated strata in the eastern and southeastern Bighorn Basin were caused by comparably smaller catchment areas and the finer-grained siliciclastic strata eroded from nearby ranges. The conglomeratic and sand-dominated strata of the southwestern area of the Bighorn Basin were caused by large, braided fluvial systems with catchments that extended into the Sevier thrust belt, where more resistant source lithologies, including Neoproterozoic quartzites, were eroded. The northernmost early Paleogene strata represent the coalescence of these fluvial systems as well as rivers and catchments that extended into southwestern Montana that contained more resistant, crystalline lithologies. These factors generated the thick, laterally extensive fluvial sand bodies common in that area of the basin. When combined with provenance patterns in adjacent Laramide basins, our data indicate asymmetric unroofing histories on either side of the Bighorn and Owl Creek Mountains. The Powder River Basin to the east of the Bighorn Mountains displays a clear Precambrian crystalline provenance, and the Wind River Basin to the south of the Owl Creek Mountains displays provenance similarities to Lower Paleozoic strata, in contrast to provenance in the Bighorn Basin, which indicates less substantial unroofing. We infer that the differing unroofing histories are due to the dominant vergence direction of the underlying basement reverse faults. Overall, this provenance pattern persisted until ca. 50 Ma, when more proximal igneous and volcaniclastic units associated with the Absaroka and Challis volcanics became major sediment sources and the Idaho River system became the dominant transport system in the area.
Тези доповідей конференцій з теми "Sediment transport direction":
1
Dorokhova, Evgenia, Evgenia Dorokhova, Dmitry Dorokhov, and Dmitry Dorokhov. "SEDIMENT MAPPING AND TRANSPORT PATHWAYS IN THE NEARSHORE ZONE OF THE RUSSIAN PART OF THE SOUTH-EASTERN BALTIC SEA." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b9489e8deb2.41910928.
Анотація:
To achieve a more robust interpretation of sediment conditions and transport, our study combines the two different interpretation techniques. A side-scan sonar survey was used as a basis for detail sedimentological investigation. Grain-size analyses of grab samples provided sediment transport direction and decoding of sonar data. The new detail lithological map of the underwater shore slope of the northern Sambian peninsula and the Russian part of the Curonian spit in 1:50 000 scale is created. For the first time, the stretched zone of very fine sands is outlined at depths of 25-30 m of the Curonian spit underwater slope. These sands are relicts, and their formation is connected with accumulative processes on the ancient shores of the Baltic Sea. Separate morpho-lithodynamic cells are distinguished on the submarine slope of the northern Sambian peninsula coast up to a depth of 20 m. The cape areas of the Sambian peninsula serve as cell boundaries where a divergence of sediment trend and seabed erosion are observed. The convergence of sediment transport directions is confined to the bight’s central parts. Fine and very fine-grained sand accumulation prevails here.
2
Dorokhova, Evgenia, Evgenia Dorokhova, Dmitry Dorokhov, and Dmitry Dorokhov. "SEDIMENT MAPPING AND TRANSPORT PATHWAYS IN THE NEARSHORE ZONE OF THE RUSSIAN PART OF THE SOUTH-EASTERN BALTIC SEA." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b43152071d3.
Анотація:
To achieve a more robust interpretation of sediment conditions and transport, our study combines the two different interpretation techniques. A side-scan sonar survey was used as a basis for detail sedimentological investigation. Grain-size analyses of grab samples provided sediment transport direction and decoding of sonar data. The new detail lithological map of the underwater shore slope of the northern Sambian peninsula and the Russian part of the Curonian spit in 1:50 000 scale is created. For the first time, the stretched zone of very fine sands is outlined at depths of 25-30 m of the Curonian spit underwater slope. These sands are relicts, and their formation is connected with accumulative processes on the ancient shores of the Baltic Sea. Separate morpho-lithodynamic cells are distinguished on the submarine slope of the northern Sambian peninsula coast up to a depth of 20 m. The cape areas of the Sambian peninsula serve as cell boundaries where a divergence of sediment trend and seabed erosion are observed. The convergence of sediment transport directions is confined to the bight’s central parts. Fine and very fine-grained sand accumulation prevails here.
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Babakov, Alexander, Alexander Babakov, Boris Chubarenko, and Boris Chubarenko. "SEDIMENT TRANSPORT NEAR THE VISTULA SPIT (BALTIC SEA)." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b93751e4b25.42106675.
Анотація:
The Vistula Spit is a sandy elongated barrier form which borders the Vistula Lagoon from the Baltic Sea. The evolution of the spit as well as nowadays sediment transport along the marine shore of it are still under discussion, especially due to existing of entrance jetties bordered the Strait of Baltiysk, the single inlet to the Vistula Lagoon, and advanced up to 10 m depth seaward. Different hypothesizes about ether uniform transport from north to south or contrary directed fluxes with convergence at various points at the spit shore are discussed. Most of them are based on fact of accumulation of sandy material just to north from the northern entrance jetty as in incoming corner. Basing on statistics of near-surface wind, direct measurements of currents and analysis of direction of the scour hole located between jetties the paper confirms the existence of two opposite fluxes - one brings alluvium from the Vistula River mouth to north as main winds blow from south-west and west, and, in contrast, another one brings material obtained by erosion of the western shore of the Sambian Peninsula to south. Dynamic equilibrium between these fluxes through hundreds of years resulted in formation of present shape of the coastline, and it is expected that the area of the equilibrium in alongshore migrations is in the top of the Yantarny- Baltiysk concave. Appearance of entrance jetties of the Vistula Lagoon inlet, in the area where opposite alongshore migration of material are nearly equalised, leaded to the accretion-erosion pattern, which is pseudo equal to sediment transport from north to south. In fact the accumulation of sand just to north from the northern entrance jetty and erosion to south from southern jetty may be explained by mechanism, when the sand transported in the incoming corner just near the northern mole by southward migrations is excluded from migratory movement and deposited in the zone shadowed by jetties (from northward migrations). Erosion to south of jetties is explained by wind surges in incoming corner for prevailing western winds.
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Babakov, Alexander, Alexander Babakov, Boris Chubarenko, and Boris Chubarenko. "SEDIMENT TRANSPORT NEAR THE VISTULA SPIT (BALTIC SEA)." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b4315e36e45.
Анотація:
The Vistula Spit is a sandy elongated barrier form which borders the Vistula Lagoon from the Baltic Sea. The evolution of the spit as well as nowadays sediment transport along the marine shore of it are still under discussion, especially due to existing of entrance jetties bordered the Strait of Baltiysk, the single inlet to the Vistula Lagoon, and advanced up to 10 m depth seaward. Different hypothesizes about ether uniform transport from north to south or contrary directed fluxes with convergence at various points at the spit shore are discussed. Most of them are based on fact of accumulation of sandy material just to north from the northern entrance jetty as in incoming corner. Basing on statistics of near-surface wind, direct measurements of currents and analysis of direction of the scour hole located between jetties the paper confirms the existence of two opposite fluxes - one brings alluvium from the Vistula River mouth to north as main winds blow from south-west and west, and, in contrast, another one brings material obtained by erosion of the western shore of the Sambian Peninsula to south. Dynamic equilibrium between these fluxes through hundreds of years resulted in formation of present shape of the coastline, and it is expected that the area of the equilibrium in alongshore migrations is in the top of the Yantarny- Baltiysk concave. Appearance of entrance jetties of the Vistula Lagoon inlet, in the area where opposite alongshore migration of material are nearly equalised, leaded to the accretion-erosion pattern, which is pseudo equal to sediment transport from north to south. In fact the accumulation of sand just to north from the northern entrance jetty and erosion to south from southern jetty may be explained by mechanism, when the sand transported in the incoming corner just near the northern mole by southward migrations is excluded from migratory movement and deposited in the zone shadowed by jetties (from northward migrations). Erosion to south of jetties is explained by wind surges in incoming corner for prevailing western winds.
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Hao, Jialing, Xiaoxin Jiang, and Juan Yang. "Three-Dimensional Numerical Model of Wind-Driven Current in a Lake Based on POM Model." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79898.
Анотація:
Lake current is the cause for the transport of many matters such as suspended sediment, algae, contaminant, therefore, it must be estimated fairly accurately. Generally speaking, the flow in many lakes is weak and the flow direction is follows dominated mainly by the wind direction on lake surface. Correct simulation of the wind-driven current in a lake requires using a three-dimensional hydrodynamic numerical model. The main factor affecting the lake hydrodynamic processes is wind. Because wind-driven current have important influence for the matter exchange and energy transform in a lake, and field observations are comparatively difficult, numerical modeling is the main method to estimate the wind-driven current nowadays. The numerical modeling of 3D tidal flow and mass transportation in this study was performed using the Princeton Ocean Model (POM). The model is validated by calculating wind-driven current in a rectangular flume [1][2]. The contaminant transport modeling in the Yangchenghu Lake is performed with POM using an orthogonal curvilinear grid in horizontal direction and sigma coordinate variation in vertical direction. An analysis of model results is presented.
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Jangir, Pramod Kumar, Kevin C. Ewans, and Ian R. Young. "Comparison of Ocean Wave Direction Spectra Estimated Using an Array of Three Optech Laser Sensors and a Directional Waverider Buoy." In ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/omae2023-101196.
Анотація:
Abstract Accurate measurement of the directional properties of waves is needed for a variety of applications, including the safe and economical operation of offshore and shipping industries, climate monitoring, air-sea interaction, and sediment transport. Recent studies have indicated differences in significant wave heights (Hm0) estimated from Eulerian and Lagrangian measurement types of approximately 10%. Similar differences might be expected in measurements of directional properties due to the different measurement principles. Spatial arrays of wave sensors and Directional Waverider (pitch/roll) buoys are commonly used to measure direction wave spectra. This paper compares directional spectra estimated from wave measurements made with a spatial array of three Optech Lasers and a Directional Waverider Buoy operating at North Rankin A platform located on the northwest coast of Australia, using the maximum likelihood method (MLM). This comparison reveals the following: (a) the mean wave directions from the spatial array and the Waverider differ by up to approximately 20°; (b) the Waverider directional spreading at the spectra peak is narrower compared to the spatial array; however, (c) at frequencies above 1.3 times the peak frequency (f = 1.3fp), the directional spreading from the Laser array is narrower compared to the Waverider. (d) The directional spreading estimates of the Waverider at the spectral peak is a weak function of inverse wave age (U10CP), particularly at higher sea states; however, the Laser array measurements do not show such a dependence.
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NOSHI, YASUHITO, TAKAAKI UDA, AKIO KOBAYASHI, and TAKAYUKI YOSHINO. "UPCOAST EXPANSION OF EROSION OPPOSITE TO DIRECTION OF PREDOMINANT LONGSHORE SAND TRANSPORT OBSERVED IN FUTTSU POINT." In Coastal Sediments 2015. WORLD SCIENTIFIC, 2015. http://dx.doi.org/10.1142/9789814689977_0038.
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Han, Xiao, and Ning Zhang. "Coastal Hydrodynamic and Sediment-Salinity Transport Simulations for Southwest Louisiana Using Measured Vegetation Data." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51571.
Анотація:
Storm-surge flood is a major thread to the inhabitants and the health of the marshes in Southwest Louisiana. The floods caused direct damages to the area, but also indirectly caused excessive sedimentations in the water system, especially in Calcasieu Ship Channel which is a vital industrial water way connecting the City of Lake Charles to the Gulf. It is well known that coastal wetlands and marshes have significant impacts on the prevention and reduction of coastal floods. The wetland vegetation creates larger frictions to the flooding water and acts as the first line of defense against any storm surge floods. In this study, we center Calcasieu Ship Channel, and hydrodynamic and sediment transport simulations were conducted for Calcasieu Ship Channel and surrounding areas. The target area ranges from the city of Lake Charles as the north end and the Gulf of Mexico as the south end, and includes three connected water systems, Calcaiseu Lake, Prien Lake and Lake Charles. The entire Calcasieu Ship Channel running from north to south is included in the domain along with the Gulf Intracoastal Waterway (GIWW) in east and west directions. In authors’ previous study, only the area of south portion of the ship channel, Calcasieu Lake and its surrounding wetlands was simulated and studied. This study is a major upgrade to the model, which provides more complete understanding of the flow and sediment transport in the entire area, as well as the interactions among all water systems surrounding the ship channel. There are wetlands (two National Wild Life Refuges, one in the west and one in the east) surrounding Calcaiseu Lake, while there are various of vegetated and non-vegetated areas surrounding Prien Lake and Lake Charles. The standard 2-D depth averaged shallow water solver was utilized for the simulation of the flow phase and a standard Eulerian scalar transport equation was solved for the sediment and salinity phases. In the sediment phase, the sediment deposition and re-suspension effects are included, while in the salinity phase, the precipitation and evaporation are included. A realistic vegetation model was implemented to represent various types of vegetation coverage in the target area, and appropriate friction values were assigned to different non-vegetated areas. Measured and observed vegetation data were utilized. A coastal storm surge flood was simulated, and effects of vegetation on flood reduction and sediment distribution were investigated. The total flooded area, the flood speed, and the distribution of the flooding water and sediments were compared between vegetated and non-vegetated areas to show the differences between different types of surfaces.
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Bobykina, Valentina, Valentina Bobykina, Boris Chubarenko, Boris Chubarenko, Konstantin Karmanov, and Konstantin Karmanov. "MORPHODYNAMICS OF THE SHORES OF THE VISTULA SPIT (THE BALTIC SEA) IN A PERIOD OF 2002-2015 BY RESULTS OF IN-SITU MEASUREMENTS." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b943e73f9e6.07698800.
Анотація:
For the first time, the quantitative characteristics of the Vistula Spit shore dynamics based on the ground-based monitoring data for 2002-2015 were presented. On the sea shore, 3 sections can be distinguished by the direction of coastal processes, i.e. the stable section to the north of the Strait of Baltiysk, the eroded 4-km section to the south of the Strait of Baltiysk, with maximum erosion rate up to 2 m/year; in the remaining area of the Spit (21 km) to the Polish border there is an alternation of stable, eroded and accumulative areas. Since 2011, a steady erosion (in the stable segments of the third section) and general weakening of the erosion rate (in the second section) have been recorded. 50% of the length of the lagoon shore was the subject to annual active erosion (0.2 - 1.4 m/year). The beaches of the sea and lagoon shores of the Vistula Spit were mainly composed of medium sands. The alongshore variability in particle size distribution on the sea and lagoon shores (according to the 2015 survey data) actually fail to correlate with long-term dynamic processes, with the exception of the steadily eroded 4-kilometer area on the sea coast to the south of the Strait of Baltiysk. Variations in the composition of sediment along the shore on the shoreline are most likely associated with the results of the latest wave processing (or storm processing and eolian transport in the case of an average beach sample).
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Bobykina, Valentina, Valentina Bobykina, Boris Chubarenko, Boris Chubarenko, Konstantin Karmanov, and Konstantin Karmanov. "MORPHODYNAMICS OF THE SHORES OF THE VISTULA SPIT (THE BALTIC SEA) IN A PERIOD OF 2002-2015 BY RESULTS OF IN-SITU MEASUREMENTS." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b4315ec153d.
Анотація:
For the first time, the quantitative characteristics of the Vistula Spit shore dynamics based on the ground-based monitoring data for 2002-2015 were presented. On the sea shore, 3 sections can be distinguished by the direction of coastal processes, i.e. the stable section to the north of the Strait of Baltiysk, the eroded 4-km section to the south of the Strait of Baltiysk, with maximum erosion rate up to 2 m/year; in the remaining area of the Spit (21 km) to the Polish border there is an alternation of stable, eroded and accumulative areas. Since 2011, a steady erosion (in the stable segments of the third section) and general weakening of the erosion rate (in the second section) have been recorded. 50% of the length of the lagoon shore was the subject to annual active erosion (0.2 - 1.4 m/year). The beaches of the sea and lagoon shores of the Vistula Spit were mainly composed of medium sands. The alongshore variability in particle size distribution on the sea and lagoon shores (according to the 2015 survey data) actually fail to correlate with long-term dynamic processes, with the exception of the steadily eroded 4-kilometer area on the sea coast to the south of the Strait of Baltiysk. Variations in the composition of sediment along the shore on the shoreline are most likely associated with the results of the latest wave processing (or storm processing and eolian transport in the case of an average beach sample).
Звіти організацій з теми "Sediment transport direction":
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Rice, J. M., M. Ross, H E Campbell, R. C. Paulen, and M. B. McClenaghan. Net evolution of subglacial sediment transport in the Quebec-Labrador Sector of the Laurentide Ice Sheet, Quebec and Newfoundland and Labrador. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/332151.
Анотація:
The interior of the Laurentide Ice Sheet (LIS) had a dynamic polythermal base. However, the subglacial thermal organization of the LIS and its evolution throughout glaciation are poorly constrained. Specifically, the net effect of ice divide migration on subglacial processes and the resulting landforms and sediments remains poorly understood. The results of a regional-scale till sampling program within the interior of the Quebec-Labrador sector of the LIS were used to explore dispersal patterns across a region known to have experienced ice divide migration. Indicator mineral and clast lithology analysis, coupled with multivariate analysis of the till matrix geochemistry, were used collectively, and evaluated within the context of the relative ice flow chronology and subglacial thermal evolution to augment our understanding of how ice divide migration impacts subglacial erosion and sedimentary processes. Indicator minerals (e.g., goethite and orthopyroxene) and clasts (e.g., iron formation clasts from the Labrador Trough) form glacial dispersal patterns that are consistent with the earliest northeast-trending ice-flow phase identified in the region. This early ice-flow phase produced and transported till across the entire study area (&gt; 175 km). However, till matrix geochemistry shows a strong relationship with the local underlying bedrock, especially the major oxides. This relationship is relatively common in areas of thin till cover and resistant bedrock lithologies. The results also indicate that following the northeast ice-flow phase, erosion and till production became more localized, without considerable transport in a single sustained direction. These results are consistent with a transition to more sporadic warm-based conditions and ice divide migration, as ice sheet reconstructions indicate, and are supported by targeted 10Be data from erratics and bedrock surfaces. There are also spatial relationships between the dispersal of fresh or re-entrained debris and paleo-ice streams identified in the landform record, as evidenced by the dispersal of indicator minerals. The reworking of previously dispersed material during subsequent ice-flow phases resulted in complex dispersal patterns across the study area. These results provide important insights for ice sheet modelling and future mineral exploration programs in inner ice sheet regions of the LIS and demonstrate the importance of a thorough understanding of ice-flow history.
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Ziegler, Nancy, Nicholas Webb, Adrian Chappell, and Sandra LeGrand. Scale invariance of albedo-based wind friction velocity. Engineer Research and Development Center (U.S.), May 2021. http://dx.doi.org/10.21079/11681/40499.
Анотація:
Obtaining reliable estimates of aerodynamic roughness is necessary to interpret and accurately predict aeolian sediment transport dynamics. However, inherent uncertainties in field measurements and models of surface aerodynamic properties continue to undermine aeolian research, monitoring, and dust modeling. A new relation between aerodynamic shelter and land surface shadow has been established at the wind tunnel scale, enabling the potential for estimates of wind erosion and dust emission to be obtained across scales from albedo data. Here, we compare estimates of wind friction velocity (u*) derived from traditional methods (wind speed profiles) with those derived from the albedo model at two separate scales using bare soil patch (via net radiometers) and landscape (via MODIS 500 m) datasets. Results show that profile-derived estimates of u* are highly variable in anisotropic surface roughness due to changes in wind direction and fetch. Wind speed profiles poorly estimate soil surface (bed) wind friction velocities necessary for aeolian sediment transport research and modeling. Albedo-based estimates of u* at both scales have small variability because the estimate is integrated over a defined, fixed area and resolves the partition of wind momentum be-tween roughness elements and the soil surface. We demonstrate that the wind tunnel-based calibration of albedo for predicting wind friction velocities at the soil surface (us*) is applicable across scales. The albedo-based approach enables consistent and reliable drag partition correction across scales for model and field estimates of us* necessary for wind erosion and dust emission modeling.
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Li, Honghai, Grace Maze, Kevin Conner, and John Hazelton. Sediment transport modeling at Stono Inlet and adjacent beaches, South Carolina. Engineer Research and Development Center (U.S.), December 2021. http://dx.doi.org/10.21079/11681/42501.
Анотація:
This report documents a numerical modeling investigation for dredged material from nearshore borrow areas and placed on Folly Beach adjacent to Stono Inlet, South Carolina. Historical and newly collected wave and hydrodynamic data around the inlet were assembled and analyzed. The datasets were used to calibrate and validate a coastal wave, hydrodynamic and sediment transport model, the Coastal Modeling System. Sediment transport and morphology changes within and around the immediate vicinity of the Stono Inlet estuarine system, including sand borrow areas and nearshore Folly Beach area, were evaluated. Results of model simulations show that sand removal in the borrow areas increases material backfilling, which is more significant in the nearshore than the offshore borrow areas. In the nearshore Folly Beach area, the dominant flow and sediment transport directions are from the northeast to the southwest. Net sediment gain occurs in the central and southwest sections while net sediment loss occurs in the northeast section of Folly Island. A storm and a 1-year simulation developed for the study produce a similar pattern of morphology changes, and erosion and deposition around the borrow areas and the nearshore Folly Beach area.
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Ptsuty, Norbert, Andrea Habeck, and Christopher Menke. Shoreline position and coastal topographical change monitoring at Gateway National Recreation Area: 2017–2022 and 2007–2022 trend report. National Park Service, August 2023. http://dx.doi.org/10.36967/2299536.
Анотація:
This trend report summarizes the results of shoreline position and coastal topography monitoring conducted at Gateway National Recreation Area (GATE) in 2007 through 2022. The data collection and report were completed by Rutgers University for the National Park Service, Northeast Coastal and Barrier Network, Inventory and Monitoring Program. Gateway National Recreation Area (GATE) is made up of three units: Sandy Hook Unit, Jamaica Bay Unit (Breezy Point, Plumb Beach), and Staten Island Unit (Great Kills, Miller Field, Fort Wadsworth). Shoreline position change results include a spatial depiction and statistical analysis of annual changes and 5-year changes in shoreline position as well as a longer-term trend analysis incorporating the full shoreline analysis of 2007 through 2022, all following the model presented in Psuty et al. (2022a). Coastal topography datasets include profiles of survey data collected annually, annual change metrics, net change metrics, as well as an alongshore depiction of net change, following the model presented in Psuty et al. (2012). This 2007–2022 trend report is the third GATE trend report to incorporate both shoreline position and coastal topographical change data. Due to the variable exposure to incident waves influencing inputs of sediment to the alongshore transport system in the various units from updrift sources, there was no common direction of shoreline displacement or profile change throughout the GATE park units. Engineering structures along the beach and adjacent to inlets altered the shoreline position and coastal topography responses in much of GATE. Generally, the largest vectors of shoreline position change and changes in coastal topography were produced by natural impacts such as storms and by anthropogenic impacts such as dredging or beach nourishment at an updrift location. All of the park units in GATE displayed the impacts of an absence of a source of sediment to counter the erosional impacts of the coastal storms. All of the units had a net inland displacement of shoreline position over the survey period, with some short term recovery associated with local pulses of sediment transfer. Sites with ocean exposure were more heavily eroded (Sandy Hook Oceanside, Breezy Point Oceanside, and Great Kills Oceanside), than sheltered sites (Sandy Hook Bayside, Breezy Point Bayside, Great Kills Bayside, Plumb Beach, Miller Field, Fort Wadsworth). A comparison of the shoreline position and profile data from this survey period with those from the previous trend reports highlights the impacts of Hurricane Sandy and the variety of recovery episodes throughout GATE (Psuty et al. 2018). The trend lines for the sites are often divided into pre-Hurricane Sandy (2012) and post- Hurricane Sandy because of the magnitude of the changes to the shoreline position (1D) and coastal topography (2D) metrics. There was considerable resilience in the system to re-establish the dune-beach system, although not in its original location. The continuing negative sediment budget and the increasing rate of relative sea-level rise will result in episodic inland migration of the dune-beach system and will necessitate a concomitant review of the allocation of space for visitor use and recreation.
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Psuty, Norbert, Christopher Menke, Katherine Ames, Andrea Aabeck, and Casey Jones. Shoreline position and coastal topographical change monitoring at Assateague Island National Seashore: 2005–2020 trend report. National Park Service, April 2022. http://dx.doi.org/10.36967/nrr-2293154.
Анотація:
This trend report summarizes the results of shoreline position and coastal topography surveys conducted semi-annually from the spring of 2005 through the fall of 2020. Shoreline position was collected in the Assateague Island National Seashore (ASIS), the Assateague State Park, and the Chincoteague National Wildlife Refuge, whereas coastal topography was collected only in the Assateague Island National Seashore and the Assateague State Park. The assembled datasets are processed to provide spatial depictions and statistical analyses of annual changes, 5-year changes, and the extended 15-year changes. Although there were considerable variations in the alongshore dimensions of change, the largest and most consistent vectors of annual shoreline position and coastal topography changes were produced by storm impacts, such as Hurricane Sandy and the winter storms in 2016, followed by the subsequent recovery. As a result of Hurricane Sandy (October 2012), the entire oceanside shoreline position of Assateague Island was displaced inland, and there was a loss of total cross-section area in the profiles. There was variable recovery post-Hurricane Sandy in both the shoreline position and coastal topography profiles. The winter of 2016 was also particularly stormy and had a higher mean net landward shoreline position displacement than post-Hurricane Sandy. Throughout the survey period, the termini of the island were exceptionally dynamic. The northern 2.5 km of Assateague Island National Seashore had a mean net seaward displacement, whereas the southern portion of the Chincoteague National Wildlife Refuge was the site of major inland displacement along the oceanside and as well as downdrift seaward extension of Toms Cove Hook. From 2005 through 2020, the only section of the oceanside shoreline position that had a positive trend of mean net displacement was the northernmost portion of Assateague Island, associated with local conditions created by the presence of the ebb tide delta and the Ocean City inlet jetty. All other parts of the ocean shoreline position had a negative trend of change; the highest rate of erosion occurred at the southern portion of Chincoteague National Wildlife Refuge. Contrary to the oceanside shoreline position, a portion of the Toms Cove Hook shoreline had a trend of seaward displacement as the spit extended in the direction of sediment transport. Other trends occurred in the areas where profiles were surveyed. Most of the dune area in ASIS gained in cross-section over time, except for portions of Assateague State Park. The dune elevation tended to gain in ASIS North and lower in ASIS South. Other than the profiles in Assateague State Park, the total cross-section area increased, with the highest rate of cross-section area gain in the northern portion of Assateague Island.