• Journal of Environmental Impact Assessment
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• v.18 no.3
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• pp.185-193
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• 2009

This study documented and diagnosed the status and problems of coastal dredging and offshore disposal of dredged sediments in South Korea to improve assessment procedures for marine environmental impacts and develop effective management systems. A total of $729({\times}10^6)m^3$ of coastal sediment was dredged in the harbors during the period of 2001-2008. Most of dredged sediment was disposed to the land dumping sites whereas ocean disposal accounted for less than 5%. Ocean disposal areas were especially concentrated to the exclusive economic zone (EEZ) in the southeast of Busan, which is not only an important fishing area for fishermen, but also considered to be spawning and nursery ground for some commercial fish species. To minimize negative impacts of dredging and ocean disposal of coastal sediment on marine ecosystem and potential strife among coastal users, we suggest 1) in development projects involving ocean disposal, it should be mandatory to propose careful reuse plans in the land, and 2) guidelines of environmental assessment and consequence management programs should be developed and implemented.

• Journal of Environmental Impact Assessment
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• v.18 no.3
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• pp.131-141
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• 2009

We studied improvement in marine environmental impact assessment and related management systems of coastal sediments that are dredged inshore but disposed offshore. After reviewing and diagnosing the existing assessment procedures and problems, we recommend to design the core assessment items and improve the reliability of assessment byenhancing the quality assurance/quality control (QA/QC) and verification processes. We proposed eco-friendly disposal plan for dredging sediment such as reuse system in land development was explored. A marine environmental database system was established to support the assessment processes. Guidelines for marine research and modelling were proposed for improving assessment of dredging and disposal of coastal sediment. Also, applying of screening and scoping for marine environmental assessment was reviewed.

• Journal of Environmental Impact Assessment
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• v.24 no.5
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• pp.444-455
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• 2015

In relation to the utilization and disposal of dredged sediment caused by coastal dredging project, we diagnosed the status of legal standard and system, and proposed the improvement plan. Dredging costal sediment distinguished the usage and the disposal by the Standard for the Beneficial Usage of Dredged Sediment. The site where disposal has been completed could be used as a site for developmental project. In case of the usage of dredged sediment for reclamation, we found that the adaptation of the Standard for Beneficial Usage of Dredged Sediment is appropriate for reclamation considering the characteristic of soil, the differences of variables, and the distinction of standard analysis methods. The current the Standard for Beneficial Usage of Dredged Sediment requires the improvement with the usage of dredging coastal sediment in the following. First, the Standard needs to include the standard of the discrimination for reclamation. Second, the current Standard is necessary to be divided by two levels, it needs to be mitigated considering human health risk. Third, it is necessary to consider both the marine environmental impact assessment and mitigation plan near coastal dredging area.

• Journal of Korean Port Research
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• v.11 no.2
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• pp.203-214
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• 1997

Hydraulic dredgers(Hopper dredger) are the most important piece of equipment in the entire harbor engineering field, and most suitable for the removal of sand and weakly consloidated sediment such as silt. In maintenance dredging, specially confined harbor or congested passage area, Hopper dredger is user most popularly because less obstruction and danger to navigation than other mostly stationary dredgers. Investigation of the physical behave of dredged material disposal in coastal water from the Hopper dredger includes estimations of pattern as well as thickness of material on the bottom. Calculation based on vertical settling and horizontal advection of single particles ignore the effects of bulk properties of the disposed marterial, vertical and horizontal diffusion. and material dilution due to the entrainment of ambient water during descent. This paper focuses on the analysis of dredging and dumping characteristics and the spatial and temporal changes in the dumping fields for the water column and bottom at a hypothetically confined coastal water. This model accounts the behavior of material after release from the hopper dredger. It is shown that the model describes the qualitative feature of prototype dumping process and its response.

• 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.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.345-354
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• 2009

The review of statements and coastal development characteristics in South Korea were diagnosed by the consultation on the coastal area utilization in Korea. The occupation and the use of public water were dominated by installation of coastal structure and seawater supply and drainage whereas the reclamation areas were predominantly utilized for developing industrial complex, harbor, fishing port and road. The occupation and the use were dominant in western coast, but reclamation was dominant in southern coast of Korea. The number of utilization cases was particularly greater in Jeonnam, Gyeongnam, and Gyeonggi Province including Incheon. The number of the statements reviews increased by more than 200 cases in 2008 compared with 2007, and most of them were the simple statements. The statements related to ocean disposal of dredged sediment, reclamation, dredging sediment, seawater supply and drainage, and marine sand mining were submitted for review. Coastal utilization was especially active in the regions of seawater quality criteria I and II. In particular, special management sea areas designated under the relevant marine regulations were utilized mostly by reclamation for developing harbor, fishing port and coastal structure. Development activities in national parks comprised primarily structure installation and coastal maintenance. In the fisheries resources protection areas, 40% of the total cases accounted for coastal maintenance, 31% for structure installation, and 16% for seawater supply and drainage. In addition, alternative plans for the improvement in policies and system of marine environmental impact assessment were suggested to enhance the function and confidence of the consultation on the coastal area utilization in Korea.

• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.466-476
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• 2016

Dredging is inevitably necessary for the management of water infrastructure such as waterways and polluted bottom sediment. Dredged material management options may be offshore dumping, wetland creation, beach nourishment and various other engineering uses depending on the given circumstances at the time of dredging. Among those options, wetland creation and beach nourishment are the preferred ones in Korea considering significant loss of wetland and beach erosion due to various development projects along the coastal region. In order to use dredged material beneficially, however, dredged material needs to be assessed its suitability with respect to its engineering purpose and environmental criteria. In this paper, we demonstrate that environmental risk of dredged material to be introduced into the marine environment can be easily assessed using biomarkers with relative low cost. Biomarkers can also compliment pollutant contents analysis that may not be specific to their impact on biological response. Biomarker information may be used to assist decision making process in selecting suitable treatment or beneficial use options for dredged materials.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.5
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• pp.423-432
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• 2004

In coastal area of Inchon, dredging and the disposal of dredged material for sea-wall construction and reclamation have increased in recent years. These activities may impact the benthic environment and result in changes in benthic communities, but little information is available on the extent and direction of these changes. We investigated whether there have been changes in the dominant macrobenthic species and benthic community over the last decade, and explored the relationship between environmental variables and spatial patterns of macrobenthic community structure. We sampled macrobenthos and recorded environmental variables in the coastal habitats of Inchon in March and June 2004. In total, 212 macrobenthic species were recorded during this study, predominately crustaceans $(34{\%})$, mollusks $(32{\%})$ and polychaetes $(21{\%})$. The mean density of macrobenthos was $1,393\;ind./m^{2}$.The most abundant species was Amphioplus japonicus $(20.5{\%})$, followed by Heteromastus filiformis $(14.4{\%})$, Theora fragilis $(8.2{\%})$ and Ampharete sp. $(4.0{\%})$. Over the past decade the dominant macrobenthic species in this area shifted. Multivariate analysis (multidimensional scaling) revealed significant differences in community structure among three regions: the middle part of the sampling area (B), site 8 (C) and other sites (A). Mean density varied significantly among the three regions, but no differences in the number of species and diversity (H') were observed. The distribution of the macrobenthic community was affected by environmental variables such as percentage sand content and sediment kurtosis. Species that were important in different areas included A. japonicus in region A, Raeta puchella in region B and T. fragilis in region C. The important species in regions B and C were filter-feeding bivalves, and the abundance of these species may be related to the increase in percentage sand content. We suggest that the sediment composition (percentage sand content) may be an important factor in determining the dominant species and structure of the macrobenthic communities in coastal Inchon. Long-term monitoring programs are necessary to understand ongoing changes in the benthic communities of this area.