• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.1
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• pp.47-55
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• 2004

A SS prediction system using GUI in coastal region has been developed to predict the dispersion of the suspended sediments occurred by dredging. The prediction system uses a finite element hydrodynamic model to calculate water level and velocities and a random-walk particle tracking model to simulate SS dispersion. The system was applied to hindcast the tidal currents and SS concentrations in the Kunsan coastal waters. The simulated tidal currents showed good agreements with the observed currents. The transport model was verified for analytic solutions and field observation showing good agreements.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.4
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• pp.14-30
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• 2015

This paper attempted to analyze the hydraulic effects that the dredging can take as an alternative to reduce possible damages of flooding due to the overflow of river levee in meandering rivers, where riverbed aggradation, seepage and erosion may occur. In order to make a hydraulic analysis in a section of meandering rivers, a two-dimensional hydraulic analysis model, RMA-2, was selected. The GIS was applied to construct two-dimensional finite element grids to consider the hydraulic conditions before and after dredging. The water surface elevations, depths, velocities, and tractive forces were compared before and after the dredging. The difference of water surface elevation between the inside and outside of river was turned out to be the maximum value of 0.58m under the design flood condition. It could be evaluated that the tractive force at the bank decreased about 42 to 67% on average for all the sections. These results could give valuable information that the dredging of the stream channel at the meandering sections decreased the risk of overflow, seepage and erosion of the banks. The methodologies given in this study will contribute to mitigating the flood damages in the surrounding farmlands.

• Water Engineering Research
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• v.6 no.1
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• pp.17-30
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• 2005

The bed evolution of the stretch of the River Rhine between km-812.5 and km-821.5 is characterised by general bed degradation as a result of the river training works and dredging activities of the last two centuries. The degradation of the river bed affects the water levels, and so the navigation conditions. To combat the erosion of the river bed with the aim to keep up the shipping traffic and to avoid the ecological system damages due to water level reductions, sand-gravel-mixtures were added to the river (so called artificial grain feeding activities). This paper presents the results of an application of a graded sediment transport model in order to study morpholodynamical characteristics due to artificial grain feeding activities in the river stretch. The finite element code TELEMAC2D was used for flow calculation by solving the 2D shallow water equation on non-structured grids. The sediment transport module SISYPHE has been developed for graded sediment transport using a multiple layer model. The needs to apply such graded sediment transport approaches to study morphological processes in the domain are discussed. The calculations have been carried out for the case of middle water flow and different size-fraction distributions. The results show that the grain feeding process could be well simulated by the model.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.83-91
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• 2018

Land reclamation, coastal construction, coastline extension and port construction, all of which involve dredging, are increasingly required to meet the growing economic and societal demands in the coastal zone. During the land reclamation, a portion of landfills are lost from the desired location due to a variety of causes, and therefore prediction of sediment transport is very important for economical and efficient land reclamation management. In this study, laboratory disposal tests were performed using an open channel, and suspended sediment transport was analyzed according to flow velocity and grain size. The relationships between the average and standard deviation of the deposition distance and the flow velocity were almost linear, and the relationships between the average and standard deviation of deposition distance and the grain size were found to have high non-linearity in the form of power law. The deposition distribution of sediments was demonstrated to have log-normal distributions regardless of the flow velocity. Based on the experimental results, modeling of suspended sediment transport was performed using deep neural network, one of deep learning techniques, and the deposition distribution was reproduced through log-normal distribution.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.48-51
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• 1998

This paper presents the transport and removal of organic substances from the contaminated soft soils and sludges such as marine dredging waste, marine sediments, mine tailing waste, and sewage sludge by electroosmosis. A series of laboratory experiments including variable conditions such as contamination levels, solid contents, and applied voltage rates were peformed with the contaminated soft clay specimen mixed with organic substance. Investigated are specimen density, dewatering rate, outflow rate, and outflow concentration. The test results showed that organic substances in the soils were removed by applied voltages. The results indicated that this process can be used efficiently to clean up the contaminated soil.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.179-183
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• 2006

As there are many human activities in the coastal regions, various facilities and coastal engineering structures for protecting beach have been built. Dredging work, reclamation and harbor construction have caused the topography of sea floor to change rapidly. So sedimentation in the vicinity of the groins has get dull and the serious aspects sometimes turn up. Analyzing the surface sediments with transport vector model is one of the good methods to understand the sedimentation in the vicinity of the groins. I analyzed the transport vector of the surface sediments in the vicinity of the groins at the region where serious beach erosion happens near Pohang harbor.

• Smart Structures and Systems
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• v.26 no.6
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• pp.781-796
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• 2020

Prediction of total sediment load is essential in an extensive range of problems such as the design of the dead volume of dams, design of stable channels, sediment transport in the rivers, calculation of bridge piers degradation, prediction of sand and gravel mining effects on river-bed equilibrium, determination of the environmental impacts and dredging necessities. This paper is aimed to investigate and predict the total sediment load of the Wadi Arbaat in Eastern Sudan. The study was estimated the sediment load by separate total sediment load into bedload and Suspended Load (SL), independently. Although the sediment records are not sufficient to construct the discharge-sediment yield relationship and Sediment Rating Curve (SRC), the total sediment loads were predicted based on the discharge and Suspended Sediment Concentration (SSC). The turbidity data NTU in water quality has been used for prediction of the SSC in the estimation of suspended Sediment Yield (SY) transport of Wadi Arbaat. The sediment curves can be used for the estimation of the suspended SYs from the watershed area. The amount of information available for Khor Arbaat case study on sediment is poor data. However, the total sediment load is essential for the optimal control of the sediment transport on Khor Arbaat sediment and the protection of the dams on the upper gate area. The results show that the proposed model is found to be considered adequate to predict the total sediment load.

• Ecology and Resilient Infrastructure
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• v.5 no.1
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• pp.25-34
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• 2018

This study presents prediction and historical analysis of the long-term bed elevation change in the Mankyung-gang River. The study area is a 25 km long reach including middle and lower courses of the Mankyung-gang River. HEC-RAS program was used for numerical predictions, and values of roughness coefficients were calibrated. Then, predictions were made in the two periods, seven years from 1986 to 1993 and twelve years from 1993 to 2005. Simulation results were compared with two sets of measured data for bed elevations. Four sediment transport formulas, namely MPM's, Toffaleti's, MPM-Toffaleti's, and Yang's formula, were tested. Simulation results showed that none of the four sediment transport formulas predicted the bed elevation change in the period of 1986 - 1993. This is related to the fact that dredging work was performed in the upstream reach in the period of 1986 - 1993, and sediment was deposited in this part severely later. However, it was found that MPM-Toffaleti's formula predicted properly the bed elevation change for the period of 1993 - 2005.

• Journal of the Korean Geosynthetics Society
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• v.15 no.1
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• pp.71-81
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• 2016

To evaluate the effects of magnetic force for transporting the dredged soil, magnetic energy inducing device was installed at the dredger. The whole length of transporting pipeline reaches more than 8.5km and the efficiency of the system and the characteristics of the flow are critical factors. The main parameters which govern the flow are flow-rate, velocity, concentration and slip-layer's condition, so in the field test monitoring system was applied to check the real time conditions of the closed circuit flow and the main parameters. From analyzing the relation between the dredged soil amounts and the pump power, it can be concluded that the magnetic forces effect on the transporting system, increase the transporting quantities of dredged soil and decrease power consumption of the pump.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.349-357
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• 2011

This study has an objective to estimate effect on water-quality enhancement by removal of contaminated river-bed material using a two-dimensional numerical modeling in the Seonakdong River, the Pyunggang River and the Maekdo River. RMA2 and RMA4 models were used for flow and contaminant transport simulation, respectively. After the analysis of the effects of flow restoration plan for the Seonakdong River system made by Lee et al (2008), simulation have been performed about scenarios which contains operations of the Daejeo Gate, the Noksan Gate, the Makdo Gate (on planning), and the Noksan Pumping Station. Because there is no option for elution from bed sediment in the RMA4 model, a simple technique has been used for initial condition modification for elution. The analyses revealed that the effect on water quality improvement due to dredging of bed sediment seemed to be less than 10 % of the total effect. The most efficient measure for the water quality improvement of the river system was the linked operation of water-gates and pumping station.