• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.124-124
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• 2018

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.619-626
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• 2014

In this paper, it was constructed the halophyte Mesocosm experimental which was used tidal flat and dredged sediment as a substrate material. Depending on the vegetation and substrate material of Mesocosm, Mesocosm A(tidal flat sediment + Salicornia herbacea), Mesocosm B (only dredged sediment), Mesocosm C(dredged sediment + Salicornia herbacea). Monitoring was carried out of Warter quality factots(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P), water temperature, salinity), Sediment factors(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P)) and growth of Salricornia herbacea. Habitat Stability Index of vegetation was calculating by using the monitoring results. HSI of Mesocosm C was calculated from 0.87 to 0.95 as compared to the relatively high HSI in Mesocosm A, it was evaluated to be able to be used in the restoration and construction of the coastal salt marsh with dredged sediment.

• Journal of Korean Society on Water Environment
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• v.37 no.1
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• pp.1-9
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• 2021

The depletion of dissolved oxygen (DO) in urban streams has a profound effect on the aquatic ecosystem; however, the change in DO by resuspension of sediments and the cause have not been sufficiently investigated. In this study, the physicochemical properties (particle size, and the content of organic and heavy metals) of the sediments of an urban stream (Anyang Stream) and the characteristics of water quality changes (DO, dissolved organic carbon (DOC), dissolved nitrogen (DN), sediment oxygen demand (SOD), and adenosine triphosphate (ATP)) by sediment resuspension were investigated. The sediment content of fine particles (< 0.2 mm) increased from 36.7% to 52.7% from the upstream to the downstream, and the contents of heavy metals and organic matter of the sediment were also higher towards the downstream. The depletion of DO by resuspension was observed in the sediment at the downstream sites (P8, P9), where the fine particle content was high, and biological SOD (BSOD) was more than 88% compared to the total SOD. The increase in BSOD coincided with the increase in ATP. It was also confirmed that the depletion of DO could increase the amount of heavy metals (such as Fe, Mn, and Pb) released from the sediment. Based on the above results, it can be concluded that resuspension of sediments induces rapid water quality changes and may cause accidents, such as fish mortality, during rainfall, and such a water quality effect can be more pronounced in sediments with a high content of fine particles and organic matter and high biological activity.

• Journal of Soil and Groundwater Environment
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• v.28 no.5
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• pp.1-11
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• 2023

The phenomenon of sediment resuspension in rivers and lakes causes contaminants (heavy metals and nutrients) accumulated in the sediment to leach into the overlying water. As a result, it can lead to changes in toxic effects and eutrophication in the aquatic ecosystem. In this regard, it is important to quantitatively determine the amount of contaminants leached during sediment resuspension. In this study, methods for assessing the amount of released contaminants and the types of contaminants potentially released due to sediment resuspension were studied and summarized. Methods for assessing leaching can be divided into three groups based on the principle of causing resuspension: (i) the oscillating grid chamber method, (ii) the mechanical stirrer method, and (iii) the shaker method. It was confirmed that the types of contaminants that can potentially be released include heavy metals bound to sulfides, as well as exchangeable and labile forms of heavy metals and nutrients. To effectively manage stable aquatic ecosystems in the future, a simplified leaching test method is needed to assess in advance the risks (i.e., changes in toxic effects and eutrophication) that sediment resuspension may pose to aquatic ecosystems.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.690-700
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• 2008

The Soil and Water Assessment Tool (SWAT) model users tend to use the readily available input dataset, such as the Ministry of Environment (MOE) land cover data ignoring temporal and spatial changes in land cover. The SWAT model was calibrated and validated with this land cover data. The EI values were 0.79 and 0.85 for streamflow calibration and validation, respectively. The EI were 0.79 and 0.86 for sediment calibration and validation, respectively. With newly prepared landcover dataset for the Doam-dam watershed, the SWAT model better predicts hydrologic and sediment behaviors. The number of HRUs with new land cover data increased by 70.2% compared with that with the MOE land cover, indicating better representation of small-sized agricultural field boundaries. The SWAT estimated annual average sediment yield with the MOE land cover data was 61.8 ton/ha/year for the Doam-dam watershed, while 36.2 ton/ha/year (70.7% difference) of annual sediment yield with new land cover data. Especially the most significant difference in estimated sediment yield was 548.0% for the subwatershed #2. Therefore it is recommended that one needs to carefully validate land cover for the study watershed for accurate hydrologic and sediment simulation with the SWAT model.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.85-85
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• 2020

South Korea experiences few large scale erosion and sedimentation problems, however, there are numerous local sedimentation problems. A reliable and consistent approach to modelling and management for sediment processes are desirable in the country. In this study, field measurements of sediment concentration from 34 alluvial river basins in South Korea were used with the Modified Einstein Procedure (MEP) to determine the total sediment load at the sampling locations. And then the Flow Duration-Sediment Rating Curve (FD-SRC) method was used to estimate the specific degradation for all gauging stations. The specific degradation of most rivers were found to be typically 50-300 tons/㎢·yr. A model tree data mining technique was applied to develop a model for the specific degradation based on various watershed characteristics of each watershed from GIS analysis. The meaningful parameters are: 1) elevation at the middle relative area of the hypsometric curve [m], 2) percentage of wetland and water [%], 3) percentage of urbanized area [%], and 4) Main stream length [km]. The Root Mean Square Error (RMSE) of existing models is in excess of 1,250 tons/㎢·yr and the RMSE of the proposed model with 6 additional validations decreased to 65 tons/㎢·yr. Erosion loss maps from the Revised Universal Soil Loss Equation (RUSLE), satellite images, and aerial photographs were used to delineate the geospatial features affecting erosion and sedimentation. The results of the geospatial analysis clearly shows that the high risk erosion area (hill slopes and construction sites at urbanized area) and sedimentation features (wetlands and agricultural reservoirs). The result of physiographical analysis also indicates that the watershed morphometric characteristic well explain the sediment transport. Sustainable management with the data mining methodologies and geospatial analysis could be helpful to solve various erosion and sedimentation problems under different conditions.

• Ocean and Polar Research
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• v.28 no.4
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• pp.369-383
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• 2006

The Saemangeum project is one of the biggest reclamation efforts in Korea and may cause coastal ecosystem change due to altered environments and habitat loss. Since February 2002, benthic environment and community structure in the Saemangeum studied area were studied to assess the influence of the project on macrofaunal community. The result of seasonal study from February, 2002 to August 2005 is reported here. Overall, changes of species numbers and dominant species of benthic animals in the periods before (1988) and after $(2002{\sim}2005)$ the Saemangeum dike construction were not evident both inside and outside the dike. However, local environmental and community change were noted The partial completion of Saemangeum dike $(4^{th}\;dike)$ in June 2003 altered water circulation and sediment deposition patterns both inside and outside the dike. Fine sediment was accumulated inside and outside the $4^{th}$ dike while coarse sediment dominated near the main channel (Sinsi gate). Benthic community resl)ended to the altered sediment type in these areas. Species number and diversity in both site was low compared to other sites. The dominant species in these areas were composed of the benthos that had not commonly occurred in the Saemangeum subtidal area.

• Korean Journal of Ecology and Environment
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• v.34 no.4 s.96
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• pp.342-348
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• 2001

The present work is to introduce the preliminary experimental results for a primary hydrocyclones process in lake sediment thickening. A few cyclones based on the Rietema standard geometry were prepared. The test particles were sediments from a local lake and waste coal fly ash for a reference test. As a result of the chemical analysis, organic contaminants were abundantly found in smaller particles in overflow. Experimental results showed that the physical characteristics of particles, configuration of the cyclone and operating variables including feed solids concentration and volumetric flow rate could affect the separation efficiency. The limiting feeding velocity for the separation and enrichment of particles was 1.5 m/s, higher separation efficiency, in general, was obtained under the high velocity with the small cyclones.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.777-787
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• 2017

Organic enrichment and pollution was investigated in surface sediments from Jinhae Bay and Geoje-Hansan Bay of Korea, which contain the largest oyster farms in Korean coastal areas. Geochemical indicators (chemical oxygen demand, total organic carbon, ignition loss, and acid volatile sulfide) in sediments, ammonium and nitrate in pore water, and bioluminescence inhibition test for sediment extracts were analyzed. Temporal changes of organic enrichment were also investigated using sediment core samples from Geoje-Hansan Bay. The level of organic pollution in sediments from Jinhae Bay was significantly greater than that of sediments from Geoje-Hansan Bay. Compared with other sites, Jinhae Bay was one of the most polluted coastal areas of Korea. The levels of geochemical indicators in May were comparable to, or higher than, in August. Ammonium concentrations in pore water were two orders of magnitudes greater than the nitrate concentrations, suggesting that the bays are reducing environments. The concentrations of total organic carbon in core sediment samples from shellfish-farming areas increased significantly from 2000 to the present year, and it seems to be associated with increases in anthropogenic activities.

• Journal of Environmental Science International
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• v.28 no.12
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• pp.1085-1099
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• 2019

We investigated the spatial and temporal variation in characteristics and pollution assessment of sediments in the watersheds of Andong-Dam and Imha-Dam, in Korea. Surface sediments were collected from six sites once a year for three years (2015-2017), and analyzed for organic matter (water content, IL, COD, TOC, TN, and TP), grain size, and concentration of trace metals (Al, Li, Zn, Cr, Pb, Cu, Ni, and As). Organic matter generally tended to increase, and was higher in the Andong watershed compare to Imha watershed. Surface sediments were mainly composed of silt. Coarse sediments were mainly distributed at the site adjacent to Andong-Dam, and showed fining after coarsening. Fine sediment were mainly distributed at the site adjacent to Imha-Dam, and were gradually coarsening. Concentration of trace metals generally tended to increase, and was higher for sites in watershed of Andong watershed (PLI > 1) than for sites in Imha watershed (PLI < 1). Trace metals in the study area were considered to be affected by fine sediment (silt), and contamination of trace metals was somewhat affected by Pb, and greatly affected by Zn and As.