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1
Torfs, Hilde, Marc Huygens, and Limbaya Tito. "Influence of the Cross-Section on the Erosion Criteria for Partly Cohesive Sediments." Water Science and Technology 29, no. 1-2 (January 1, 1994): 103–11. http://dx.doi.org/10.2166/wst.1994.0656.
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Erosion of sediment mixtures, comprising cohesive as well as non-cohesive sediments, has been studied in straight laboratory flumes of circular and rectangular cross-sections. Erosion of mixed sediments depended on the mixture composition (cohesive material content), the type of cohesive sediment, and the shape of the flume cross-section. By increasing the cohesive material content, the erosion resistance of the sediment mixture also increased and the erosion pattern changed from ripples and dunes (noncohesive) to a groove or wavy surface (cohesive). In circular channels, the influence of the “side” walls on sediment transport is important, but the criteria for incipient motion seem to be the same as in the rectangular channels. Hence, sediment transport models developed for rectangular channels cannot be readily applied to circular channels.
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Milburn, David, and B. G. Krishnappan. "Modelling Erosion and Deposition of Cohesive Sediments from Hay River, Northwest Territories, Canada." Hydrology Research 34, no. 1-2 (February 1, 2003): 125–38. http://dx.doi.org/10.2166/nh.2003.0032.
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A large volume sample of river-bed cohesive sediment and water from Hay River, Northwest Territories, Canada was collected during a spring field program in 2000 as part of a study on under-ice movement of sediment just before breakup. Controlled laboratory experiments were subsequently conducted on the Hay River water/sediments in a rotating annular flume at Burlington, Ontario, Canada to better understand the deposition and erosion processes of cohesive sediment transport. The deposition experiments in the rotating flume confirmed that the Hay River sediment is cohesive and the critical shear stress for deposition and the rates of deposition are a function of bed shear stress and the initial concentration of the sediment in suspension. The erosion experiments provided quantitative data on the critical shear stress for erosion and the rates of erosion as a function of bed shear stress and the age of the sediment deposit. The erosion experiments also indicated that the growth of the biofilm had an influence on the erosion characteristics of the Hay River sediment. Based on the data from the rotating circular flume experiments, a modelling strategy is proposed for calculating the under-ice transport of the cohesive sediments in the Hay River.
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Krishnappan, Bommanna G. "Recent advances in basic and applied research in cohesive sediment transport in aquatic systems." Canadian Journal of Civil Engineering 34, no. 6 (June 1, 2007): 731–43. http://dx.doi.org/10.1139/l06-043.
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An overview of cohesive sediment transport processes is given in this paper, and a mass-balance equation that is commonly used to treat cohesive sediment transport is reviewed. The equation highlights transport parameters and processes that are important for modelling the transport of cohesive sediment. The flocculation mechanism that distinguishes cohesive sediment from its noncohesive counterpart is elaborated using a laboratory study that was carried out in a rotating circular flume using sediments from Hay River, Northwest Territories, Canada. A mathematical model of flocculation suitable for predicting flocculation of sediment in rotating circular flumes is reviewed. Other cohesive sediment transport processes such as erosion and deposition processes at the sediment-water interface, entrapment of fines in gravel beds, consolidation, fluid mud, and fluidization due to wave action are reviewed. Additional challenges and knowledge gaps that exist in the area of cohesive sediment transport are identified. Key words: cohesive sediment, flocculation, mathematical modelling of flocculation, rotating circular flume, erosion, deposition, fine sediment entrapment, fluid mud, consolidation, fluidization, waves.
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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.
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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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Guarnieri, A., A. J. Souza, N. Pinardi, and P. Traykovski. "Numerical modelling of sediment transport in the Adriatic Sea." Ocean Science Discussions 11, no. 3 (June 6, 2014): 1391–433. http://dx.doi.org/10.5194/osd-11-1391-2014.
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Abstract. A new sediment transport model, considering currents, tides and waves is presented for the Adriatic Sea basin. The simulations concentrate on the winter of 2002–2003 because of field data availability and interesting intermittent processes occurrence. A process oriented analysis is performed to investigate the impact that Sirocco and Bora wind regimes have on sediment transport. The comparisons of the simulations with the observed data show that the model is capable to capture the main dynamics of sediment transport along the Italian coasts and the sediment concentration within the water column. This latter can reach values up to several g L−1, especially within the first centimetres above the bottom. The sediments are transported mainly southwards along the Italian coasts, consistently with the known literature results, except during Sirocco wind events, which can be responsible for reversing the coastal circulation in the northern area of the basin, and consequently the sediment transport. The resuspension of sediments is also related to the specific wave regimes induced by Bora and Sirocco, the former inducing resuspension events near the coasts while the latter causing a more diffused resuspension regime in the Northern Adriatic basin. Beside the realistic representation of short timescales resuspension/deposition events due to storms, the model was also used to investigate persistent erosion or deposition areas in the Adriatic Sea. Two main depocenters were identified: one, very pronounced, in the surroundings of the Po river delta, and another one a few kilometres off the coast in front of the Ancona promontory. A third region of accumulation, even if less intense, was found to be offshore the southernmost limit of the Gargano region. On the contrary the whole western coast within a distance of a few kilometres from the shore was found to be subject to prevailing erosion. The comparison with observed accumulation and erosion data shows that the model captures well the main depocenters in the domain and the erosion within the very coastal belt of the western side of the basin, but seems to be too erosive in a few areas, in particular those where the contribution of sediment inflow to the sea of some minor but intermittently important rivers is not considered in a realistic way as input to the model.
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Tait, Simon J., Peter J. Rushforth, and Adrian J. Saul. "A laboratory study of the erosion and transport of cohesive-like sediment mixtures in sewers." Water Science and Technology 37, no. 1 (January 1, 1998): 163–70. http://dx.doi.org/10.2166/wst.1998.0040.
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Surveys of sewers in the UK have indicated that many sewer systems have significant in-sewer deposits. Many of these existing combined sewers have been constructed at such a gradient and experience such a range of hydraulic conditions that over a period of time they experience repeated phases of sediment deposition, erosion and transport. Deposition of sediment in sewers with its consequent loss of discharge capacity can lead to the surcharging of sewerage systems and the premature operation of combined sewer overflows. The sudden erosion and transport of large quantities of deposited in-sewer sediments during periods of increased flow can significantly contribute to the pollution load imposed on receiving water courses and sewerage treatment plants. It is therefore important not only to be able to estimate the hydraulic performance of sewers but also the conditions under which significant erosion of deposited sediments occur. This paper reports on the rationale behind and the initial results from a laboratory study which aims to investigate the erosion and transport of “cohesive-like” sediment mixtures in controlled laboratory conditions. The choice of the sediments used was aimed at representing the characteristics of sewer sediment mixtures found in the field. These deposits have been found to exhibit a significant degree of cohesion not found in previously studied granular sediment beds.
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Lisle, I. G., C. W. Rose, W. L. Hogarth, P. B. Hairsine, G. C. Sander, and J. Y. Parlange. "Stochastic sediment transport in soil erosion." Journal of Hydrology 204, no. 1-4 (January 1998): 217–30. http://dx.doi.org/10.1016/s0022-1694(97)00123-6.
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Kusuda, T., and T. Futawatari. "Simulation of Suspended Sediment Transport in a Tidal River." Water Science and Technology 26, no. 5-6 (September 1, 1992): 1421–30. http://dx.doi.org/10.2166/wst.1992.0585.
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Based on the results of field observation in a tidal river, modeling of sediment transport processes is performed and the suspended sediment transport over a long term is simulated with a newly developed procedure, in which the Lagrangian reference frame is used in order to reduce numerical dispersion. The suspended sediment transport in the tidal river is calculated with erosion and deposition of sediments, consolidation of fluid mud to bed mud, and transport by turbidity current. Sediment transport processes concerned with formation and maintenance of turbidity maxima are sufficiently simulated for a fortnightly cycle with the Lagrangian sediment transport model (LSTM).
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Bernard, Maxime, Philippe Steer, Kerry Gallagher, and David Lundbek Egholm. "Modelling the effects of ice transport and sediment sources on the form of detrital thermochronological age probability distributions from glacial settings." Earth Surface Dynamics 8, no. 4 (November 10, 2020): 931–53. http://dx.doi.org/10.5194/esurf-8-931-2020.
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Abstract. The impact of glaciers on the Quaternary evolution of mountainous landscapes remains controversial. Although in situ or bedrock low-temperature thermochronology offers insights on past rock exhumation and landscape erosion, the method also suffers from potential biases due to the difficulty of sampling bedrock buried under glaciers. Detrital thermochronology attempts to overcome this issue by sampling sediments at e.g. the catchment outlet, a component of which may originate from beneath the ice. However, detrital age distributions not only reflect the catchment exhumation, but also spatially variable patterns and rates of surface erosion and sediment transport. In this study, we use a new version of a glacial landscape evolution model, iSOSIA, to address the effect of erosion and sediment transport by ice on the form of synthetic detrital age distributions. Sediments are tracked as Lagrangian particles formed by bedrock erosion, and their transport is restricted to ice or hillslope processes, neglecting subglacial hydrology, until they are deposited. We base our model on the Tiedemann Glacier (British Columbia, Canada), which has simple morphological characteristics, such as a linear form and no connectivity to large tributary glaciers. Synthetic detrital age distributions are generated by specifying an erosion history, then sampling sediment particles at the frontal moraine of the modelled glacier. Results show that sediment sources, reflecting different processes such as glacier and hillslope erosion, can have distinct bedrock age distribution signatures, and estimating such distributions should help to identify predominant sources in the sampling site. However, discrepancies between the detrital and bedrock age distributions occur due to (i) the selective storage of a large proportion of sediments in small tributary glaciers and in lateral moraines, (ii) the large range of particle transport times due to varying transport lengths and strong variability of glacier ice velocity, (iii) the heterogeneous pattern of erosion, and (iv) the advective nature of glacier sediment transport along ice streamlines. This last factor leads to a poor lateral mixing of particle detrital signatures inside the frontal moraine, and then local sampling of the frontal moraine is likely to reflect local sources upstream. Therefore, sampling randomly across the moraine is preferred for a more representative view of the catchment age distribution. Finally, systematic comparisons between synthetic (U-Th)/He and fission track detrital ages, with different bedrock age-elevation profiles and different relative age uncertainties, show that the nature of the age-elevation relationship and age uncertainties largely control the ability to track sediment sources in the detrital record. However, depending on the erosion pattern spatially, qualitative first-order information may still be extracted from a thermochronological system with high uncertainties (>30 %). Overall, our results demonstrate that detrital age distributions in glaciated catchments are strongly impacted not only by erosion and exhumation but also by sediment transport processes and their spatial variability. However, when combined with bedrock age distributions, detrital thermochronology offers a novel means to constrain the transport pattern and time of sediment particles.
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Fox, G. A., G. V. Wilson, R. K. Periketi, and R. F. Cullum. "Sediment Transport Model for Seepage Erosion of Streambank Sediment." Journal of Hydrologic Engineering 11, no. 6 (November 2006): 603–11. http://dx.doi.org/10.1061/(asce)1084-0699(2006)11:6(603).
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Subardjo, Petrus, Agus Anugroho Dwi Suryoputro, and Ibnu Praktikto. "Sebaran Sedimen Tersuspensi di Perairan Teluk Awur Jepara menggunakan Citra Landsat 8." Buletin Oseanografi Marina 9, no. 1 (April 24, 2020): 77–82. http://dx.doi.org/10.14710/buloma.v9i1.29111.
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Sedimen tersuspensi dianggap sebagai sedimen yang didistribusikan oleh arus laut. Arus sepanjang pantai (longshore current) berperan besar terhadap proses perpindahan sedimen di perairan. Gelombang laut yang yang membentuk sudut terhadap garis pantai menyebabkan arus sepanjang pantai Transpor sedimen yang disebabkan oleh arus sepanjang panti sering menimbulkan permasalahan erosi pantai dan pendangkalan perairan. Perairan Teluk Awur memiliki bentuk teluk dan tanjung yang memungkinkan terjadinya arus sepanjang pantai. Potensi adanya proses erosi dan sedimentasi di perairan Teluk Awur membuat pentingnya kajian mengenai pola sebaran sedimen tersuspensi. Penelitian ini mampu menjelaskan tentang pola sebaran sedimen tersuspensi di perairan Teluk Awur, Kecamatan Tahunan, Kabupaten Jepara. Metode yang digunakan untuk penentuan sedimen tersuspensi menggunakan pengindraan jauh dan data yang digunakan yaitu citra satelit landsat-8. Kandungan sedimen tersuspensi tertinggi berada di Desa Teluk Awur dan Desa Demaan. Kandungan tertinggi sebesar ± 67,54 mg/L dan semakin menjauhi pantai konsentrasi menurun. Tingginya kadungan sedimen tersuspensi dipengaruhi oleh proses mixing dan intensitas curah hujan. Suspended sediments are considered as sediments distributed by ocean currents. Current along the coast (longshore current) plays a major role in the process of transfer of sediment in the waters. Sea waves that form angles to the coastline cause currents along the coast Sediment transport caused by currents along the orphanage often cause erosion and coastal silting problems. The waters of Teluk Awur have the shape of bays and headlands which allow currents along the coast. The potential for erosion and sedimentation in the Awur Bay waters makes it important to study the pattern of suspended sediment distribution. This research is able to explain the pattern of suspended sediment distribution in Awur Bay waters, Annual District, Jepara Regency. The method used to determine suspended sediment uses remote sensing and the data used are Landsat-8 satellite imagery. The highest suspended sediment content was in Teluk Awur Village and Demaan Village. The highest content of ± 67.54 mg / L and increasingly away from the beach decreased concentration. The high suspended sediment content is influenced by the mixing process and the intensity of rainfall.
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Futawatari, Tohru, Tetsuya Kusuda, Kenichi Koga, Hiroyuki Araki, Teruyuki Umita, and Katsuhiro Furumoto. "Development of a New Simulation Method for Suspended Sediment Transport in a Tidal River." Water Science and Technology 20, no. 6-7 (June 1, 1988): 103–12. http://dx.doi.org/10.2166/wst.1988.0194.
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A one dimensional simulation model of suspended sediment transport in a tidal river was developed with erosion, deposition, and thickening processes of sediments, and inflow from tributaries. This model uses the explicit leapfrog method and its lower end boundary of the river is extended into the sea to close the boundary for calculation. Laboratory experiments were performed to determine erosional and depositional rates of sediments and to study the sediment thickening process in the river under various concentrations of chlorinity and suspended solids. Numerical simulation results with the parameter values obtained experimentally did not show good agreement with observed data. Modifying the parameter values according to physical phenomena was necessary to obtain good agreement in between. After the modification, computation results during a fortnightly cycle explain satisfactorily the sediment transport phenomena in this river.
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PRITCHARD, DAVID, and ANDREW J. HOGG. "On sediment transport under dam-break flow." Journal of Fluid Mechanics 473 (December 10, 2002): 265–74. http://dx.doi.org/10.1017/s0022112002002550.
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We present exact solutions for suspended sediment transport under one-dimensional dam-break flow, both over a dry bed and into a small depth of tail water. We explicitly calculate the suspended sediment concentration, including erosion and deposition, and investigate the effect of varying the erosional and depositional models employed. These solutions order insight into sediment transport processes under floods or sheet flow events, and we also discuss their application as test-bed solutions for the validation of numerical models.
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Seco, I., M. Gómez Valentín, A. Schellart, and S. Tait. "Erosion resistance and behaviour of highly organic in-sewer sediment." Water Science and Technology 69, no. 3 (November 26, 2013): 672–79. http://dx.doi.org/10.2166/wst.2013.761.
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Reliable prediction of time-varying pollutant loads in combined sewer systems during storm periods can aid better management of the release of pollution into natural environments as well as enhancing storage tank design. Better understanding of the behaviour of sewer sediments is crucial for the development of models that adequately describe the transport of in-sewer solids and accurately predict the changes in pollutant concentration within combined sewers during storm events. This paper reports on the results of a test programme to examine the erosion of highly organic sewer sediment under the application of time-varying shear stress. The tests were carried out with and without supplying oxygen, and varying simulated dry-weather periods. The aim was to investigate the behaviour of real in-sewer sediment with a high organic content (around 80%) in an attempt to improve prediction of the transport rates under the particular Mediterranean conditions of long dry-period/build-up and intense rainfall/wash-off, and understand how this environment affects the erosional resistance and subsequent sediment release. Results have been compared with previous work on lower organic content sewer sediments and artificial organic sediment.
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Tait, S. J., R. M. Ashley, R. Verhoeven, F. Clemens, and L. Aanen. "Sewer sediment transport studies using an environmentally controlled annular flume." Water Science and Technology 47, no. 4 (February 1, 2003): 51–60. http://dx.doi.org/10.2166/wst.2003.0219.
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This paper provides an overview and some preliminary results of a collaborative project recently completed at WL Delft Hydraulics. It describes tests in an annular flume, in which sediment deposits were formed under carefully controlled and monitored environmental conditions. The deposits were then subjected to a series of time steps in which the rotational speed of the flume’s top and bottom plates was increased, progressively increasing the bed shear stress. The sediment deposits were formed using three different types of sediment. An artificial organic sediment, together with a uniformly sized sand were selected as surrogate sewer sediments. The deposits in the remaining experiments were real in-sewer sediments, from catchments in the UK (Dundee) and The Netherlands (Loenen). During the erosion tests, total and volatile suspended solids concentration, particle size distribution of the eroded sediment, and COD and DO levels were recorded. The bed surface topography was also measured so that the influence of the deposit formation condition on bedforms could also be examined. Where bed consolidation times were least 24 hours a biologically active surficial layer was observed to develop at the sediment/water interface. The initial deposit conditions (temperature and deposit duration) were both found to have a significant impact on the subsequent erosion of the deposit.
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Liu, Yan, Christiane Zarfl, Nandita B. Basu, Marc Schwientek, and Olaf A. Cirpka. "Contributions of catchment and in-stream processes to suspended sediment transport in a dominantly groundwater-fed catchment." Hydrology and Earth System Sciences 22, no. 7 (July 19, 2018): 3903–21. http://dx.doi.org/10.5194/hess-22-3903-2018.
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Abstract. Suspended sediments impact stream water quality by increasing the turbidity and acting as a vector for strongly sorbing pollutants. Understanding their sources is of great importance to developing appropriate river management strategies. In this study, we present an integrated sediment transport model composed of a catchment-scale hydrological model to predict river discharge, a river-hydraulics model to obtain shear stresses in the channel, a sediment-generating model, and a river sediment-transport model. We use this framework to investigate the sediment contributions from catchment and in-stream processes in the Ammer catchment close to Tübingen in southwestern Germany. The model is calibrated to stream flow and suspended-sediment concentrations. We use the monthly mean suspended-sediment load to analyze seasonal variations of different processes. The contributions of catchment and in-stream processes to the total loads are demonstrated by model simulations under different flow conditions. The evaluation of shear stresses by the river-hydraulics model allows the identification of hotspots and hot moments of bed erosion for the main stem of the Ammer River. The results suggest that the contributions of suspended-sediment loads from urban areas and in-stream processes are higher in the summer months, while deposition has small variations with a slight increase in summer months. The sediment input from agricultural land and urban areas as well as bed and bank erosion increase with an increase in flow rates. Bed and bank erosion are negligible when flow is smaller than the corresponding thresholds of 1.5 and 2.5 times the mean discharge, respectively. The bed-erosion rate is higher during the summer months and varies along the main stem. Over the simulated time period, net sediment trapping is observed in the Ammer River. The present work is the basis to study particle-facilitated transport of pollutants in the system, helping to understand the fate and transport of sediments and sediment-bound pollutants.
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Boukhanef, Issam, Anna Khadzhidi, Lyudmila Kravchenko, Zeroual Ayoub, and Kastali Abdennour. "Modeling of solid sediment transport in mountain rivers." E3S Web of Conferences 175 (2020): 12002. http://dx.doi.org/10.1051/e3sconf/202017512002.
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In Algeria, the problems of erosion and sediment transport are critical, since they have the most dramatic consequences of the degradation of agricultural soils on the one hand and the siltation of the dam on the other .The sediment transport in the Algerian basins is very important especially during the periods of floods, It is in this sense that this study, which consists of estimating the sediment transport in suspension and determining the models of relation linking the liquid discharge and the sediment discharge in order to estimate the solid transport in the absence of suspended sediments concentration data at the Sidi Akkacha station at the outlet of the basin of Oued Allala which is subject to a high water erosion, it degrades from one year to the other under the effect of this phenomenon especially during the floods which drain high amounts of fine particles exceeding in general, the concentration of 150 g/l, the results obtained from the application of the models are very encouraging since the correlation between liquid and solid discharge exceeds 80 %.
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Thomaz, Edivaldo Lopes. "Runoff and sediment transport in a degraded area." Revista Brasileira de Ciência do Solo 36, no. 1 (February 2012): 243–52. http://dx.doi.org/10.1590/s0100-06832012000100025.
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Gully erosion occurs by the combined action of splash, sheetwash and rill-wash (interrill and rill erosion). These erosion processes have a great capacity for both sediment production and sediment transport. The objectives of this experiment were to evaluate hydrological and sediment transport in a degraded area, severely dissected by gullies; to assess the hydraulic flow characteristics and their aggregate transport capacity; and to measure the initial splash erosion rate. In the study area in Guarapuava, State of Paraná, Brazil (lat 25º 24' S; long 51º24' W; 1034 m asl), the soil was classified as Cambissolo Húmico alumínico, with the following particle-size composition: sand 0.116 kg kg-1; silt 0.180 kg kg-1; and clay 0.704 kg kg-1. The approach of this research was based on microcatchments formed in the ground, to study the hydrological response and sediment transport. A total of eight rill systems were simulated with dry and wet soil. An average rainfall of 33.7 ± 4.0 mm was produced for 35 to 54 min by a rainfall simulator. The equipment was installed, and a trough was placed at the end of the rill to collect sediments and water. During the simulation, the following variables were measured: time to runoff, time to ponding, time of recession, flow velocity, depth, ratio of the initial splash and grain size. The rainsplash of dry topsoil was more than twice as high as under moist conditions (5 g m-2 min-1 and 2 g m-2 min-1, respectively). The characteristics of the flow hydraulics indicate transition from laminar to turbulent flow [Re (Reynolds number) 1000-2000]. In addition, it was observed that a flow velocity of 0.12 m s-1 was the threshold for turbulent flow (Re > 2000), especially at the end of the rainfall simulation. The rill flow tended to be subcritical [Fr (Froude Number) < 1.0]. The variation in hydrological attributes (infiltration and runoff) was lower, while the sediment yield was variable. The erosion in the rill systems was characterized as limited transport, although the degraded area generated an average of 394 g m-2 of sediment in each simulation.
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Lira-Pantoja, María Alejandra, Alec Torres-Freyermuth, Christian Mario Appendini, Diana Carolina Fernández, Paulo Salles, Ernesto Tonatiuh Mendoza, José López, and Adrián Pedrozo-Acuña. "CHRONIC BEACH EROSION INDUCED BY COASTAL STRUCTURES IN CHELEM, YUCATÁN." Coastal Engineering Proceedings 1, no. 33 (December 28, 2012): 125. http://dx.doi.org/10.9753/icce.v33.sediment.125.
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The Yucatan coastline has been experiencing beach erosion during the past few decades; the erosion has reached critical points at some locations such as the Chelem beach, located near the Progreso Pier. Despite this problem, only few studies have been devoted in order to investigate the role of coastal structures on explaining the high erosion rates reported at this location. Therefore, the aim of this work is to evaluate the effects of the Progreso Pier on the wave transformation and alongshore sediment transport in the study area. Field surveys were conducted in a monthly basis in order to estimate the erosion rates and wave conditions with an ADCP installed at 8 m water depth. The field information confirmed the high erosional trends (O(1)m/year) that explain coastal infrastructure damage and property losses. The wave measurements were employed as the forcing of a wind-wave numerical model (MIKE 21 SW). The numerical model is implemented in the study area for two different scenarios, with and without the pier; this was to estimate nearshore wave conditions. Subsequently, the nearshore wave climate at 5 m water depth is employed for the calculation of alongshore sediment transport rates in 5 points that are representative of the littoral drift along the study area. The modeling results show that the pier acts as a large scale wave-sheltering structure that induces important alongshore sediment transport gradients under mean wave conditions, decreasing the capacity of the waves to recover the beach. On the other hand, during winter storms, when the direction of the waves is from the NNW, the structure does not seem to play an important role on wave transformation into the study. As a result, the Progreso Pier enhances beach erosion in the Chelem area by inducing algonshore gradients in sediment transport and decreasing the beach recovery capability
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Skipworth, Peter J., Simon J. Tait, and Adrian J. Saul. "Laboratory investigations into cohesive sediment transport in pipes." Water Science and Technology 33, no. 9 (April 1, 1996): 187–93. http://dx.doi.org/10.2166/wst.1996.0208.
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In the UK many sewers are laid to shallow gradients and as a consequence, suffer from recurrent sediment deposition. The loss in conveyance due to these deposits may contribute to hydraulic overloading problems and the wash-out of in-sewer sediment deposits may result in a rain induced “foul flush” of pollution which may subsequently be discharged via a CSO to the receiving water course. This paper reports the results of a series of controlled experiments in the laboratory in an attempt to better understand the factors which influence the erosion of cohesive sediment beds. Apparatus, formerly used for fixed bed work, was modified to assess the erosion characteristics of movable beds. Samples were taken from the flow during computer generated hydrographs and these were later assessed for the concentration of suspended sediment using a spectrophotometer. Whilst other studies have been concerned with the erodability of different sediments, this study has been limited to one cohesive sediment type and has concentrated on two aspects of the relationship between the properties of the flow hydrograph and the erosion and transport of cohesive sediment beds. Specifically, the effect of the rate of increase of the rising limb of the hydrograph and of the ultimate flowrate on the pollutograph have been examined. This series of experiments has produced evidence that the measured suspended sediment transport rate of cohesive-like materials exposed to a variable flowrate, is dependent both on the values of the final flowrate and on the rate of the initial temporal change of the flowrate, and is not solely dependent on the “steady state” flow variables.
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Carroll, C., R. D. Connolly, D. M. Freebairn, J. Francis, D. M. Silburn, and B. Simpson. "A simulation study of erosion in the Emerald Irrigation Area." Soil Research 37, no. 3 (1999): 479. http://dx.doi.org/10.1071/s98096.
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Sedimentation in the drainage network of the Emerald Irrigation Area (near Emerald, Queensland), as a result of erosion from irrigated farms, is a serious problem. Deposited sediment changes the hydraulic characteristics of the drains causing flooding and is difficult and expensive to remove. We used the GLEAMS erosion model to simulate a range of management strategies aimed at reducing sedimentation in the drains by reducing erosion at the bay/field scale or retaining eroded sediment on-farm. GLEAMS was set up and tested using data measured at the rainfall simulator (12 m2), furrow (0·2–0·3 ha), and bay (20–30 ha) scales. Comparisons of measured with predicted sediment transport indicated the model accurately reproduced effects of several management treatments on sediment transport and the size distribution of eroded sediment at the bay scale. To reproduce accurately size distribution of eroded sediment, though, an important parameter, clay content of surface soil, had to be substantially distorted from measured values. GLEAMS was used to simulate sediment transport from a typical farm producing irrigated cotton. Management strategies simulated included conventional (bare), stubble retained, cover in the tail-drain, drip irrigation, and addition of a silt-trap and storage. The most effective management strategies for reducing erosion and sediment transport at the bay scale were stubble retained and drip irrigation. Stubble retained+drip irrigation almost eliminated sediment transport. Addition of a silt-trap and storage with conventional management reduced sediment transport off-farm by 45%. Use of a silt-trap with improved field management further reduced sediment transport. Erosion and sediment transport at the bay scale was sensitive to changes in the furrow/tail-drain layout. Changes in the furrow/tail-drain layout from the original design should be undertaken carefully so as not to increase sediment transport off-farm.
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Ashley, R. M., and M. A. Verbanck. "Mechanics of sewer sediment erosion and transport." Journal of Hydraulic Research 34, no. 6 (November 1996): 753–70. http://dx.doi.org/10.1080/00221689609498448.
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Pavlík, František, Miroslav Dumbrovský, Jana Podhrázská, and Jana Konečná. "The influence of water erosion processes on sediment and nutriet transport from a small agricultural catchment area." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 60, no. 3 (2012): 155–64. http://dx.doi.org/10.11118/actaun201260030155.
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Erosion processes in catchment areas cause serious ecologic and economic problems because of their negative consequences in terms of soil and water deterioration as well as for the environment as a whole. The soil particles washed down by water erosion are the biggest pollution factor due to their amount and volume. Sediments are the product of a selective process in which smaller and lighter particles are separated from eroded soil and taken away by water first. This means that the sediments contain a higher amount of organic, clay, and silt particles than the the original soils. Washed down sediments consist mainly of particles smaller than 0.05 mm (40–90% of the mixture). Other studies in the Czech Republic have focused on the assessment of soil erosion, based upon principles and parameters defined in the Universal Soil Loss Equation, but none of them has dealt with nutrient transport assessment as a consequence of water erosion. This paper presents a summary concerning the nutrient content in erosion sediment in a selected catchment area. Research work was conducted to identify and quantify the sediment load associated with nutrient transport especially from arable land on different soil types.
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Hu, Peng, Junyu Tao, Aofei Ji, Wei Li, and Zhiguo He. "A Computationally Efficient Shallow Water Model for Mixed Cohesive and Non-Cohesive Sediment Transport in the Yangtze Estuary." Water 13, no. 10 (May 20, 2021): 1435. http://dx.doi.org/10.3390/w13101435.
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In this paper, a computationally efficient shallow water model is developed for sediment transport in the Yangtze Estuary by considering mixed cohesive and non-cohesive sediment transport. It is firstly shown that the model is capable of reproducing tidal-hydrodynamics in the estuarine region. Secondly, it is demonstrated that the observed temporal variation of suspended sediment concentration (SSC) for mixed cohesive and non-cohesive sediments can be well-captured by the model with calibrated parameters (i.e., critical shear stresses for erosion/deposition, erosion coefficient). Numerical comparative studies indicate that: (1) consideration of multiple sediment fraction (both cohesive and non-cohesive sediments) is important for accurate modeling of SSC in the Yangtze Estuary; (2) the critical shear stress and the erosion coefficient is shown to be site-dependent, for which intensive calibration may be required; and (3) the Deepwater Navigation Channel (DNC) project may lead to enhanced current velocity and thus reduced sediment deposition in the North Passage of the Yangtze Estuary. Finally, the implementation of the hybrid local time step/global maximum time step (LTS/GMaTS) (using LTS to update the hydro-sediment module but using GMaTS to update the morphodynamic module) can lead to a reduction of as high as 90% in the computational cost for the Yangtze Estuary. This advantage, along with its well-demonstrated quantitative accuracy, indicates that the present model should find wide applications in estuarine regions.
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Haralampides, Katy, and Andres Rodriguez. "Erosional properties of the sediments in the Petitcodiac River estuary at Moncton, New Brunswick." Canadian Journal of Civil Engineering 33, no. 9 (September 1, 2006): 1209–16. http://dx.doi.org/10.1139/l06-066.
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The Petitcodiac River estuary was modified after the construction of a causeway in 1968 at Moncton, New Brunswick. To address some of the sediment-related issues associated with recent proposed changes to the causeway, it is essential to characterize the sediment properties. Several samples were obtained in 2003 and 2004 at eight sites from the upper 5 km of the existing estuary to determine sediment properties including particle size, bulk density, in situ water content, and organic content. These properties were determined from cores extracted from the field and reconstituted cores prepared in the laboratory. Facilities to evaluate the erosion rates of relatively undisturbed sediment cores from the field were constructed; four box cores were tested in a 10 m flume to determine erosion rates with depth. In most cases, erosion rates increased with an increase in the applied boundary shear stress and were strongly dependent on sediment properties and the depositional history of the bed.Key words: cohesive sediments, sediment transport, local boundary shear stress, erosion rates.
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Nalluri, C., and E. M. Alvarez. "The Influence of Cohesion on Sediment Behaviour." Water Science and Technology 25, no. 8 (April 1, 1992): 151–64. http://dx.doi.org/10.2166/wst.1992.0189.
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This paper describes the results of a laboratory study financed by the Science and Engineering Research Council (SERC), UK. The work was carried out at the University of Newcastle upon Tyne in collaboration with the Water Research Centre's (WRc) River Basin Management Project during the period 1987-90. The present study has covered hydraulics, deposition, erosion and sediment transport, all with deposited bed. Noncohesive sands and sewer sediment analogues (with cohesive additives to sand) have been used and throughout the study comparisons between cohesive and noncohesive sediments were made. The noncohesive sediment studies suggested that the initiation of erosion and transport rates criteria in channels of circular cross-section using bed shear stress are comparable to those of wide channels. The sewer sediment analogues corresponding to type A needed a maximum mean shear stress of around 6-7 N/m2 whereas a weaker sediment (type C) needed only around 2.5 N/m2. The chosen cohesive analogues behaved as noncohesive sediments once they started moving, perhaps a phenomenon close to reality.
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Bussi, G., X. Rodríguez-Lloveras, F. Francés, G. Benito, Y. Sánchez-Moya, and A. Sopeña. "Sediment yield model implementation based on check dam infill stratigraphy in a semiarid Mediterranean catchment." Hydrology and Earth System Sciences 17, no. 8 (August 29, 2013): 3339–54. http://dx.doi.org/10.5194/hess-17-3339-2013.
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Abstract. Soil loss and sediment transport in Mediterranean areas are driven by complex non-linear processes which have been only partially understood. Distributed models can be very helpful tools for understanding the catchment-scale phenomena which lead to soil erosion and sediment transport. In this study, a modelling approach is proposed to reproduce and evaluate erosion and sediment yield processes in a Mediterranean catchment (Rambla del Poyo, Valencia, Spain). Due to the lack of sediment transport records for model calibration and validation, a detailed description of the alluvial stratigraphy infilling a check dam that drains a 12.9 km2 sub-catchment was used as indirect information of sediment yield data. These dam infill sediments showed evidences of at least 15 depositional events (floods) over the time period 1990–2009. The TETIS model, a distributed conceptual hydrological and sediment model, was coupled to the Sediment Trap Efficiency for Small Ponds (STEP) model for reproducing reservoir retention, and it was calibrated and validated using the sedimentation volume estimated for the depositional units associated with discrete runoff events. The results show relatively low net erosion rates compared to other Mediterranean catchments (0.136 Mg ha−1 yr−1), probably due to the extensive outcrops of limestone bedrock, thin soils and rather homogeneous vegetation cover. The simulated sediment production and transport rates offer model satisfactory results, further supported by in-site palaeohydrological evidences and spatial validation using additional check dams, showing the great potential of the presented data assimilation methodology for the quantitative analysis of sediment dynamics in ungauged Mediterranean basins.
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Cessna, A. J., F. J. Larney, L. A. Kerr, and M. S. Bullock. "Transport of trifluralin on wind-eroded sediment." Canadian Journal of Soil Science 86, no. 3 (May 1, 2006): 545–54. http://dx.doi.org/10.4141/s04-075.
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Wind erosion is one of the major forms of soil degradation on the Canadian prairies. Particulate matter emanating from agricultural soil can be transported long distances in the atmosphere and, if the soil has significant clay content, would contain particles less than 2 μm in diameter. Particles of this size range have been associated with respiratory health effects in humans and if they have pesticides associated with them the risk of health effects may be increased. A field experiment was conducted near Regina, Saskatchewan, to determine the trifluralin (2,6-dinitro-N,N-dipropyl-4-trifluoromethylaniline) content in wind-eroded sediment from a soil-incorporated application of the herbicide into Regina heavy (71%) clay soil. Three wind erosion events were monitored in which the total estimated soil loss was 62.4 Mg ha-1. The concentration of trifluralin in the winderoded sediment did not show a consistently significant increase with sampler height (10 to 100 cm) and, by implication, decreasing sediment particle size. The concentration of trifluralin in the wind-eroded sediment was lower than that in the incorporation layer and in the surface soil (upper 0.5 to 1 cm). The overall wind erosion loss of trifluralin, as a percent of the amount applied, during three erosion events was 1.4%. The results of this study indicate that human exposure to atmospheric particulate matter, especially in agricultural areas, may simultaneously involve exposure to pesticides. Key words: Trifluralin, wind erosion, wind-eroded sediment, heavy clay
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Murali, Madhu K., Matthew R. Hipsey, Anas Ghadouani, and Zhiguo Yuan. "SewerSedFoam: A Model for Free Surface Flow, Sediment Transport, and Deposited Bed Morphology in Sewers." Water 12, no. 1 (January 17, 2020): 270. http://dx.doi.org/10.3390/w12010270.
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This paper aims to bridge the gap in the detailed modelling of flow and sediment process interactions in sewers through the development of a computational fluid dynamics (CFD) model. It draws on previous models developed for surface water sediment transport in the OpenFOAM CFD framework and builds on them to improve their suitability for sewer sediment processes. Three distinct sediment processes, suspended sediment transport, bedload transport, and deposited bed morphology, are incorporated into a free surface flow solver, interFoam. This sewer sediment model, called SewerSedFoam, models the impacts of sediment deposition and erosion on flow velocity by using dynamic mesh deformation to capture the movement of the deposited bed and its morphology. Further, three sediment classes, two suspended and one bedload sediment, can be modelled along with some bed stabilization and consolidation effects during deposition and erosion, respectively. The functionality of the overall model in modelling sewer sediment deposition and erosion is promising, although the validation of a large magnitude sediment erosion event has been limited by the availability of granular data in existing case studies.
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Do, Kideok, Nobuhisa Kobayashi, and Kyung-Duck Suh. "EROSION AND ACCRETION ON CURVED BEACH." Coastal Engineering Proceedings 1, no. 33 (October 18, 2012): 11. http://dx.doi.org/10.9753/icce.v33.sediment.11.
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The performance of a large nourishment project on Bethany Beach, Delaware is evaluated using available beach profile, wave and tide data during September 2007 to September 2010. The volume of the placed sand with the median diameter of 0.31 mm was about 500 m3/m along the curved shoreline of 1.8 km length. The nourished beach was attacked by two severe storms in May 2008 and November 2009. The eroded sand volume above the mean sea level (MSL) was about 70 m3/m for each of the two storms and emergency repairs were necessary. The numerical cross-shore model with multiple cross-shore lines is used to compute the cross-shore and longshore sediment transport. The beach erosion above MSL is shown to be caused by the offshore sand transport and the alongshore gradient of the longshore sand transport rate. The performance of the nourished beach is predicted to be sensitive to the sand diameter in the range of 0.23 to 0.45 mm.
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Berlamont, Jean E., and Hilde M. Torfs. "Modeling (partly) cohesive sediment transport in sewer systems." Water Science and Technology 33, no. 9 (April 1, 1996): 171–78. http://dx.doi.org/10.2166/wst.1996.0204.
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Although the basic mechanisms of sediment transport in sewers are the same as in rivers, it is not necessarily appropriate to use the many models that have been developed for sediment transport in rivers also in sewers. Different reasons are: 1) sewer sediments are often mixtures of cohesive and non cohesive material, and the bed is often stratified; 2) due to consolidation of the (partly cohesive) bed material, the erosion resistance of the bed may vary with time; 3) the flow conditions in sewers are usually unsteady, which is not accounted for in the classical sediment transport models; 4) existing models have been derived from experiments in rectangular flumes: the results are not directly applicable to sewers with circular cross section where the distribution of bed shear stress may be completely different from a rectangular section; 5) the limited availability of erodible material and the varying supply of sediments add additional difficulty to the modelling of sediment transport in sewers.
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Al Sayah, Mario J., Rachid Nedjai, Konstantinos Kaffas, Chadi Abdallah, and Michel Khouri. "Assessing the Impact of Man–Made Ponds on Soil Erosion and Sediment Transport in Limnological Basins." Water 11, no. 12 (November 29, 2019): 2526. http://dx.doi.org/10.3390/w11122526.
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The impact of ponds on basins has recently started to receive its well-deserved scientific attention. In this study, pond-induced impacts on soil erosion and sediment transport were investigated at the scale of the French Claise basin. In order to determine erosion and sediment transport patterns of the Claise, the Coordination of Information on the Environment (CORINE) erosion and Soil and Water Assessment Tool (SWAT) models were used. The impact of ponds on the studied processes was revealed by means of land cover change scenarios, using ponded versus pondless inputs. Results show that under current conditions (pond presence), 12.48% of the basin corresponds to no-erosion risk zones (attributed to the dense pond network), while 65.66% corresponds to low-erosion risk, 21.68% to moderate-erosion risk, and only 0.18% to high-erosion risk zones. The SWAT model revealed that ponded sub-basins correspond to low sediment yields areas, in contrast to the pondless sub-basins, which yield appreciably higher erosion rates. Under the alternative pondless scenario, erosion risks shifted to 1.12%, 0.52%, 76.8%, and 21.56% for no, low, moderate, and high-erosion risks, respectively, while the sediment transport pattern completely shifted to higher sediment yield zones. This approach solidifies ponds as powerful human-induced modifications to hydro/sedimentary processes.
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Ristenpart, E., R. M. Ashley, and M. Uhl. "Organic near-bed fluid and particulate transport in combined sewers." Water Science and Technology 31, no. 7 (April 1, 1995): 61–68. http://dx.doi.org/10.2166/wst.1995.0201.
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Studies in Germany, Belgium, France and Scotland have revealed that there are significant solids transport gradients in the depth of foul and combined sewage flows. Continuous field observations of changes in depths of sediment deposits in combined sewers have also indicated that there is an interaction between the erosion and deposition processes and changes in the mass transport of solids in regions in the overlying flow. A fuller understanding of the interactive phenomena is essential for both sewer sediment management and the minimization of associated pollution from wash-out of solids via CSOs. The paper presents results from the detailed studies in Hildesheim, Germany and those carried out in Dundee, Scotland, investigating the heterogeneity of solids movement with regard to gross solids, erosion of sewer sediments and their interactions with the suspended transport phases and the layer of very dense fluid found to be transported under certain circumstances, near the sediment bed or sewer invert (traditionally called ‘bed-load’).
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Deasy, C., and J. N. Quinton. "Use of rare earth oxides as tracers to identify sediment source areas for agricultural hillslopes." Solid Earth Discussions 2, no. 2 (July 1, 2010): 195–212. http://dx.doi.org/10.5194/sed-2-195-2010.
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Abstract. Understanding sediment sources is essential to enable more effective targeting of in-field mitigation approaches to reduce diffuse pollution from agricultural land. In this paper we report on the application of rare earth element oxides to arable soils at hillslope scale in order to determine sediment source areas and their relative importance, using a non-intrusive method of surface spraying. Runoff, sediments and rare earth elements lost from four arable hillslope lengths at a site in the UK with clay soils were monitored from three rainfall events after tracer application. Measured erosion rates were low, reflecting the typical event conditions occurring at the site, and less than 1% of the applied REO tracers were recovered, which is consistent with the results of comparable studies. Tracer recovery at the base of the hillslope was able to indicate the relative importance of different hillslope sediment source areas, which were found to be consistent between events. The principal source of eroded sediments was the upslope area, implying that the wheel tracks were principally conduits for sediment transport, and not highly active sites of erosion. Mitigation treatments for sediment losses from arable hillslopes should therefore focus on methodologies for trapping mobile sediments within wheel track areas through increasing surface roughness or reducing the connectivity of sediment transport processes.
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Deasy, C., and J. N. Quinton. "Use of rare earth oxides as tracers to identify sediment source areas for agricultural hillslopes." Solid Earth 1, no. 1 (November 26, 2010): 111–18. http://dx.doi.org/10.5194/se-1-111-2010.
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Abstract. Understanding sediment sources is essential to enable more effective targeting of in-field mitigation approaches to reduce diffuse pollution from agricultural land. In this paper we report on the application of rare earth element oxides to arable soils at hillslope scale in order to determine sediment source areas and their relative importance, using a non-intrusive method of surface spraying. Runoff, sediments and rare earth elements lost from four arable hillslope lengths at a site in the UK with clay soils were monitored from three rainfall events after tracer application. Measured erosion rates were low, reflecting the typical event conditions occurring at the site, and less than 1% of the applied REO tracers were recovered, which is consistent with the results of comparable studies. Tracer recovery at the base of the hillslope was able to indicate the relative importance of different hillslope sediment source areas, which were found to be consistent between events. The principal source of eroded sediments was the upslope area, implying that the wheel tracks were principally conduits for sediment transport, and not highly active sites of erosion. Mitigation treatments for sediment losses from arable hillslopes should therefore focus on methodologies for trapping mobile sediments within wheel track areas through increasing surface roughness or reducing the connectivity of sediment transport processes.
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Ferreira, Ana Margarida, and Carlos Coelho. "Artificial Nourishments Effects on Longshore Sediments Transport." Journal of Marine Science and Engineering 9, no. 3 (February 24, 2021): 240. http://dx.doi.org/10.3390/jmse9030240.
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Serious erosion problems related to significant negative sediments budgets in the coastal systems are referred worldwide. Artificial nourishments are a coastal erosion mitigation strategy that allow for a decrease in those negative budgets by adding sediment to the coastal system. Thus, it is essential to understand and adequately model the shoreline response after a nourishment operation, in order to support the definition of the best intervention scenarios. The main goal of this work was to study the artificial nourishment effects on the longshore sediment transport and consequently on the morphological evolution at the intervention site and nearby areas, in a time horizon of 5 years. The longshore transport of the nourished sediments was evaluated, aiming to contribute to the evaluation of the sediment’s permanence at the deposition site and the frequency required for new nourishments. The shoreline evolution numerical long-term configuration (LTC) model was applied in order to evaluate the spatial and temporal distribution of the nourished sediments along the coast, considering different types of beaches and incident wave climates. The adopted approach is generic and supported by simple numerical models, which can be useful for preliminary site-specific evaluations. The results show that the nourishment impact is mainly observed nearby the intervention site. It is highlighted that higher longshore sediment transport rates are associated with more energetic wave climates, but not necessarily with incident waves more oblique to the shoreline.
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Blom, G., and C. Toet. "Modelling Sediment Transport and Sediment Quality in a Shallow Dutch Lake (Lake Ketel)." Water Science and Technology 28, no. 8-9 (October 1, 1993): 79–90. http://dx.doi.org/10.2166/wst.1993.0606.
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Lake Ketel is a shallow Dutch lake, part of the river Rhine delta, with a surface area of 38 km2. Between 1960 and 1980 15×106 m3 contaminated sediment accumulated in the lake. After 1980 the contaminant load started to decrease. A common hypothesis was that the relatively clean solids supplied now, would slowly cover the contaminated sediment layer. Research indicated however a serious erosion of old and polluted bottom sediments. To quantify resuspension and sedimentation fluxes the sediment transport model STRESS-2d has been applied. Simulation results show a net sedimentation of 300×l06 kg year−1, but an erosion of old and polluted sediment of 350×106 kg year−1. In large areas in the lake net sedimentation is only a few millimetres a year, while high resuspension and sedimentation fluxes lead to an intensive interaction between sediment and water. Spatial variability in resuspension and sedimentation fluxes will lead to spatial gradients in the response of the bottom sediment to the reduced contaminant load. Based on the simulated resuspension and sedimentation fluxes, a simple model for the Cd concentration in the bottom sediment has been developed. Simulation results show a relatively fast decrease of the Cd concentration in the upper sediment layer areas with high net sedimentation and/or (brute) resuspension and sedimentation fluxes.
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Carter, Samantha C., Elizabeth M. Griffith, Peter D. Clift, Howie D. Scher, and Timothy M. Dellapenna. "Clay-fraction strontium and neodymium isotopes in the Indus Fan: implications for sediment transport and provenance." Geological Magazine 157, no. 6 (May 13, 2020): 879–94. http://dx.doi.org/10.1017/s0016756820000394.
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AbstractReconstructing the provenance of siliciclastic marine sediment is important for understanding sediment pathways and constraining palaeoclimate and erosion records. However, physical fractionation of different size fractions can occur during sediment transport, potentially biasing records derived from bulk sediment. In this study, records of radiogenic Sr and Nd isotopic composition and K/Al ratio of the separated clay fraction, as well as bulk grain size, are presented, measured from deep-sea sediments recovered from International Ocean Discovery Program (IODP) Sites U1456 and U1457 in the Arabian Sea. These new records are compared with published bulk sediment records to investigate the influence of sediment transport on these proxies and to constrain provenance evolution and its relationship to climate variability since middle Miocene time. Correlations between grain size and the bulk sediment isotopic composition confirm that transport processes are influencing the bulk sediment record. This relationship, although present, is not as strong in the clay-fraction isotopic records. Heterogeneity of bulk sediment likely drives differences between bulk and clay records, thought to be largely controlled by sediment transport processes. The isotopic records reveal variations in provenance that correlate with climatic change at 8–7 Ma, as well as an increase in overall provenance variability beginning at c. 3.5 Ma, likely linked to monsoon strength and glacial–interglacial cycles. The clay-fraction records highlight the potential value of measuring proxy records from multiple size fractions to help constrain provenance records as well as investigate sediment transport and/or weathering and erosion processes recorded in deep-sea sediment archives.
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Prestedge, Gordon K., and Christopher A. Fleming. "ANALYSIS OF A BEACH QUALITY PROBLEM." Coastal Engineering Proceedings 1, no. 20 (January 29, 1986): 108. http://dx.doi.org/10.9753/icce.v20.108.
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A study was recently undertaken to investigate sediment transport on a section of coastline where recreational beaches have experienced periodic erosion. Alongshore, onshore/offshore and aeolian sediment transport processes were investigated and quantitative transports predicted with the aid of calibration using surveys and aerial photographs. This paper describes the study and the recommendations proposed for beach quality improvements.
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Galofré, Jordi, Jordi Galofré, Dolores Ortiz, and Raúl Medina. "LONG TERM BEACH EROSION: MORPHODYNAMIC CASE STUDY IN MONT-ROIG BEACH, SPAIN." Coastal Engineering Proceedings 1, no. 33 (October 9, 2012): 68. http://dx.doi.org/10.9753/icce.v33.sediment.68.
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Long term coastal erosion in beaches induced by long-shore sediment transport is an important aspect to be taken account in beach behavior. If anthropogenic impacts in coastal stretch (harbor, detached breakwaters, lack of sediments from streams and gullies, and urban pressure) interrupting long-shore currents and transport and decreasing sediment supply, the coastal equilibrium disappears. In this paper a case study is shown in order to analyze long term beach behavior in a coastal stretch affected by erosion. After a brief description of morphological aspects, causes and effects that have incidence on the case study area will be shown. General background and coastal works are detailed. The ideas based on a classical analysis of beach behavior are exposed and results obtained from bathymetric analysis and numerical models are showed. Morphology, wave climate, morphodynamics and sediment budget are evaluated and morphodynamic beach behavior is proposed. A diagnosis is made and mitigation proposal for coastal erosion will be proposed.
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HRISSANTHOU, V., and A. PSILOVIKOS. "Distributed modeling of soil erosion and sediment transport." Bulletin of the Geological Society of Greece 34, no. 2 (August 1, 2018): 763. http://dx.doi.org/10.12681/bgsg.17354.
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A mathematical model is used for the estimation of the annual sediment yield resulting from rainfall and runoff at the outlet of Nestos River basin (Toxotes, Thrace, Greece), where the ecologically interesting Nestos delta exists. The model is applied to that part of Nestos River basin (838 km2) which lies downstream of three dams. Two dams (Thissavros and Platanovryssi) have been already constructed, while the third one (Temenos) is under construction. The model consists of three sub-models: a rainfall-runoff sub-model, a surface erosion sub-model and a sediment transport sub-model for streams. This model is also capable of computing the annual erosion amount and sediment yield in the individual sub-basins
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Shobe, Charles M., Gregory E. Tucker, and Katherine R. Barnhart. "The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution." Geoscientific Model Development 10, no. 12 (December 18, 2017): 4577–604. http://dx.doi.org/10.5194/gmd-10-4577-2017.
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Abstract. Models of landscape evolution by river erosion are often either transport-limited (sediment is always available but may or may not be transportable) or detachment-limited (sediment must be detached from the bed but is then always transportable). While several models incorporate elements of, or transition between, transport-limited and detachment-limited behavior, most require that either sediment or bedrock, but not both, are eroded at any given time. Modeling landscape evolution over large spatial and temporal scales requires a model that can (1) transition freely between transport-limited and detachment-limited behavior, (2) simultaneously treat sediment transport and bedrock erosion, and (3) run in 2-D over large grids and be coupled with other surface process models. We present SPACE (stream power with alluvium conservation and entrainment) 1.0, a new model for simultaneous evolution of an alluvium layer and a bedrock bed based on conservation of sediment mass both on the bed and in the water column. The model treats sediment transport and bedrock erosion simultaneously, embracing the reality that many rivers (even those commonly defined as bedrock rivers) flow over a partially alluviated bed. SPACE improves on previous models of bedrock–alluvial rivers by explicitly calculating sediment erosion and deposition rather than relying on a flux-divergence (Exner) approach. The SPACE model is a component of the Landlab modeling toolkit, a Python-language library used to create models of Earth surface processes. Landlab allows efficient coupling between the SPACE model and components simulating basin hydrology, hillslope evolution, weathering, lithospheric flexure, and other surface processes. Here, we first derive the governing equations of the SPACE model from existing sediment transport and bedrock erosion formulations and explore the behavior of local analytical solutions for sediment flux and alluvium thickness. We derive steady-state analytical solutions for channel slope, alluvium thickness, and sediment flux, and show that SPACE matches predicted behavior in detachment-limited, transport-limited, and mixed conditions. We provide an example of landscape evolution modeling in which SPACE is coupled with hillslope diffusion, and demonstrate that SPACE provides an effective framework for simultaneously modeling 2-D sediment transport and bedrock erosion.
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Balla, Faiza, Nabil Kabouche, Kamel Khanchoul, and Hamza Bouguerra. "Hydro-sedimentary flow modelling in some catchments Constantine highlands, case of Wadis Soultez and Reboa (Algeria)." Journal of Water and Land Development 34, no. 1 (September 26, 2017): 21–32. http://dx.doi.org/10.1515/jwld-2017-0035.
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Abstract Erosion is a major phenomenon that causes damage not only to soil and agriculture, but also to the quality of the water amounting to tonnes of matter annually transported on the earth's surface. This fact has attracted the interest of researchers to understand its mechanism and explain its causes and consequences. This work is a comparative study of water erosion in the two semi-arid catchments of Wadi Soultez and Wadi Reboa; located in the North-East of Algeria. The approach adopted for the quantification of sediment transport consists on researching the best regressive model to represent the statistical relation between the sediment yield and the measured water discharge at different scales: annual, seasonal and monthly. The available data cover 27 years from 1985-2012. The results show that the power model has given the best correlation coefficient. Results have indicated that Wadi Reboa transported an average of 14.66 hm3 of water and 0.25 million tonnes of sediments annually. While Wadi Soultez has transported 4.2 hm3 of water and 0.11 million tonnes of sediments annually. At a seasonal scale, sediment amounts have showed significant water erosion in autumn with around 44% and secondarily in the spring with 29% in Wadi Soultez. Unlike Wadi Reboa, sediment transport represents 32% and 46% in autumn and spring respectively. Based on the obtained sediment amounts; it is found that the physical factors: such as steep reliefs, vulnerable lithological nature of rocks and poor vegetal cover, have significantly contributed in accelerating soil erosion.
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Matmon, A., P. J. Haeussler, and ASTER Team. "Sediment sources and transport by the Kahiltna Glacier and other catchments along the south side of the Alaska Range, Alaska." Geosphere 16, no. 3 (March 10, 2020): 787–805. http://dx.doi.org/10.1130/ges02190.1.
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Abstract Erosion related to glacial activity produces enormous amounts of sediment. However, sediment mobilization in glacial systems is extremely complex. Sediment is derived from headwalls, slopes along the margins of glaciers, and basal erosion; however, the rates and relative contributions of each are unknown. To test and quantify conceptual models for sediment generation and transport in a simple valley glacier system, we collected samples for 10Be analysis from the Kahiltna Glacier, which flows off Denali, the tallest mountain in North America. We collected angular quartz clasts on bedrock ledges from a high mountainside above the equilibrium line altitude (ELA), amalgamated clast samples from medial moraines, and sand samples from the river below the glacier. We also collected sand from nine other rivers along the south flank of the Alaska Range. In the upper catchment of the Kahiltna drainage system, toppling, rockfall, and slab collapse are significant erosional processes. Erosion rates of hundreds of millimeters per thousand years were calculated from 10Be concentrations. The 10Be concentrations in amalgamated samples from medial moraines showed concentrations much lower than those measured from the high mountainside, a result of the incorporation of thick, and effectively unexposed, blocks into the moraine, as well as the incorporation of material from lower-elevation nearby slopes above the moraines. The 10Be sediment samples from downstream of the Kahiltna Glacier terminus showed decreasing concentrations with increasing distance from the moraine, indicating the incorporation of material that was less exposed to cosmic rays, most likely from the glacier base as well as from slopes downstream of the glacier. Taken together, 10Be concentrations in various samples from the Kahiltna drainage system indicated erosion rates of hundreds of millimeters per thousand years, which is typical of tectonically active terrains. We also measured 10Be concentrations from river sediment samples collected from across the south flank of the Alaska Range. Calculation of basinwide weighted erosion rates that incorporated hypsometric curves produced unrealistically high erosion rates, which indicates that the major source of sediment was not exposed to cosmic rays and was primarily derived from the base of glaciers. Moreover, the apparently high erosion rates suggest that parts of each drainage system are not in erosional steady state with respect to cosmogenic isotope accumulation.
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Aguilar, Germán, Albert Cabré, Victor Fredes, and Bruno Villela. "Erosion after an extreme storm event in an arid fluvial system of the southern Atacama Desert: an assessment of the magnitude, return time, and conditioning factors of erosion and debris flow generation." Natural Hazards and Earth System Sciences 20, no. 5 (May 11, 2020): 1247–65. http://dx.doi.org/10.5194/nhess-20-1247-2020.
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Abstract. The contribution of an individual extreme storm event to long-term erosion rates has been estimated for the first time in the Atacama Desert. A mean erosion of 1.3 mm has been calculated for the March 2015 event that impacted the southernmost part of the Atacama Desert. The estimated erosion is consistent with millennial erosion rates and the previously reported return times of high-sediment-discharge events in the study area. This is significant because erosion rates, related to events of high sediment discharge in arid fluvial systems, are difficult to measure with sediment loading due to destruction of gauges by devastating flash floods and therefore have not been directly measured yet. During the March 2015 storm, debris flows were reported as the main sediment transport process, while gullies and channels erosion were the main source of sediments that generated debris flows reaching the tributary junctions and the trunk valleys. Sediment yield at tributary outlets is highly dependent on the ability of catchments to store sediments in stream networks between storms. The largest tributary catchments, the high hydrological hierarchy, the low topographic gradient and the gentle slopes are the most determining factors in generating debris flows capable of reaching alluvial fans in any storm event from large sediment volumes stored in the stream networks. Our findings better assess the susceptibility to debris flow of arid catchments, which is significant for the southernmost valleys of the Atacama Desert because human settlements and industries are mostly established in alluvial fans.
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Beer, A. R., and J. M. Turowski. "Bedload transport controls bedrock erosion under sediment-starved conditions." Earth Surface Dynamics 3, no. 3 (July 13, 2015): 291–309. http://dx.doi.org/10.5194/esurf-3-291-2015.
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Abstract. Fluvial bedrock incision constrains the pace of mountainous landscape evolution. Bedrock erosion processes have been described with incision models that are widely applied in river-reach and catchment-scale studies. However, so far no linked field data set at the process scale had been published that permits the assessment of model plausibility and accuracy. Here, we evaluate the predictive power of various incision models using independent data on hydraulics, bedload transport and erosion recorded on an artificial bedrock slab installed in a steep bedrock stream section for a single bedload transport event. The influence of transported bedload on the erosion rate (the "tools effect") is shown to be dominant, while other sediment effects are of minor importance. Hence, a simple temporally distributed incision model, in which erosion rate is proportional to bedload transport rate, is proposed for transient local studies under detachment-limited conditions. This model can be site-calibrated with temporally lumped bedload and erosion data and its applicability can be assessed by visual inspection of the study site. For the event at hand, basic discharge-based models, such as derivatives of the stream power model family, are adequate to reproduce the overall trend of the observed erosion rate. This may be relevant for long-term studies of landscape evolution without specific interest in transient local behavior. However, it remains to be seen whether the same model calibration can reliably predict erosion in future events.
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Johnson, Bradley, and Jesse McNinch. "LONG-TERM MORPHOLOGICAL EVOLUTION MODEL." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 64. http://dx.doi.org/10.9753/icce.v36.sediment.64.
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Nearshore morphology models predicting storm-scale erosion have been in use for the past several decades. These empirical tools typically focus on a single time-scale, which limits the utilization. For example, models developed to predict cross-shore storm erosion are poorly suited for longer-term simulations that include the beach recovery between events and gradients in longshore transport. Herein, the one-dimensional model CSHORE is extended to include shoreline change associated with along- shore variation in transport. A comparison of model predictions with long-term shoreline data from South Carolina demonstrate reasonable agreement with both erosion and accretion.
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Preston, Nick. "Compiling records of Holocene erosion and sediment transport." PAGES news 17, no. 2 (June 2009): 85. http://dx.doi.org/10.22498/pages.17.2.85.
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Merritt, W. S., R. A. Letcher, and A. J. Jakeman. "A review of erosion and sediment transport models." Environmental Modelling & Software 18, no. 8-9 (October 2003): 761–99. http://dx.doi.org/10.1016/s1364-8152(03)00078-1.
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Aksoy, Hafzullah, Gil Mahe, and Mohamed Meddi. "Modeling and Practice of Erosion and Sediment Transport under Change." Water 11, no. 8 (August 12, 2019): 1665. http://dx.doi.org/10.3390/w11081665.
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Climate and anthropogenic changes impact on the erosion and sediment transport processes in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes from natural areas to cultivated areas, and then from degraded areas to desertification. Such areas, under the effect of anthropogenic activities, are more sensitive to erosion, and are therefore prone to erosion. On the other hand, with an increase in the number of dams in watersheds, a great portion of sediment fluxes is trapped in the reservoirs, which do not reach the sea in the same amount nor at the same quality, and thus have consequences for coastal geomorphodynamics. The Special Issue “Modeling and Practice of Erosion and Sediment Transport under Change” is focused on a number of keywords: erosion and sediment transport, model and practice, and change. The keywords are briefly discussed with respect to the relevant literature. The papers in this Special Issue address observations and models based on laboratory and field data, allowing researchers to make use of such resources in practice under changing conditions.