• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.4
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• pp.158-177
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• 2023

An estuary is a transitional water area that links the land and sea through rivers and streams, transporting various components from the land to the sea, which plays an important role in determining primary productivity in the coastal environment, and this coastal ecosystem captures a huge amount of carbon into biomass, known as blue carbon, which mitigates climate change as a potential carbon reservoir. This study examined the variation of mean grain size and organic carbon content of the surface sediments for 6 years and analyzed their relationship in the western and southern estuarine areas (Han River Estuary, Geum River Estuary, Yeongsan River Estuary, Seomjin River Estuary, and Nakdong River Estuary) and the East Sea upwelling area. During the sampling period (2015 to 2020), seasonal variation of both properties was not observed, because their variations might be controlled by diverse oceanographic environments and hydrographic conditions within each survey area. However, despite the synoptic problem of all samples, the positive relationship was obtained between the averages of mean grain size and organic carbon content, which clearly distinguishes each survey area. The unique positive relationship in all estuarine areas implies that the same process by sediment clay particles is important in the organic carbon accumulation. However, additional important factor may be expected in the organic carbon accumulation in the East Sea upwelling area. Further necessary data (sedimentation rate, dry bulk density etc) should be required for the estimation of carbon stock to evaluate the major estuaries in Korea as potential carbon reservoirs in the coastal environment.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.205-214
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• 2013

In Yeongsan River estuary, located in the southern West Coast, a dike was constructed in December 1981. After the construction of a dike, discharge mechanism of fresh water has been changed, the water quality and chlorophyll-a are expected to be influenced by fresh water discharge. We investigated temporal and spatial variations and long-term trend of phytoplankton biomass (chlorophyll-a) and environmental factors. The concentrations of nutrient and chlorophyll-a were generally high in summer and the concentrations were increased toward downstream. Surface/bottom salinity difference was negatively correlated with salinity in surface water but positively with nutrient and chlorophyll-a. TN, TP and DIN concentrations were generally increased over 10 years. This study can provide information for better management of water quality for Youngsan River estuary.

• Environmental and Resource Economics Review
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• v.21 no.4
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• pp.981-998
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• 2012

In this paper, several count data model of travel cost recreation demand with Poisson and negative binominal specification are applied to estimate the value of access to the estuary area of Yeongsan river from visitor survey data. The results show that the negative binomial model that accounts for truncation and overdispersion provides the better goodness-of-fit, and therefore the value per visit(i.e. consumer surplus) is 89,350 won for resident of Jeolla province and 432,526 won for that of other provinces. If don't correct overdispersion by relying on Poisson estimates, the consumer surplus will be underestimated. Whereas the consumer surplus will be overestimated unless correct truncation by using estimates of untruncated models. As a result, the truncated negative binomial model should be applied to estimate the travel demand and the consumer surplus per visit by using survey data from single site visitors.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.376-389
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• 2022

Despite the consumption of disinfectants have been increased by COVID-19 pandemic, the fate of the chemicals in aquatic food webs are still unclear. In order to understand the trophic transfer of the chemicals, the concentration of disinfectants including six benzalkonium chloride (BACs) and five didecyldimethylammonium chlorides(DDACs) were measured at the Geum (2020), Han (2021), and Yeongsan River (2021), before and after rainfall. The highest concentration of ∑BACs (mainly C12 and C14) and ∑DDACs (mainly C10 and C14) were observed in the Han River, followed by Yeongsan River, Geum River Estuary, and Gapcheon. After rainfalls, both concentration and detection frequency were decreased in all sites. Although the BAC and DDAC seems to be accumulated in organisms, they were bio-diluted rather than magnified in the aquatic food web with the biomagnification factor(BMF) of less than 1, trophic magnification slope (TMS) from -0.236 to 0.001, and trophic magnification factor(TMF) from 0.85 to 1.01.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.285-292
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• 2019

Our study was based on the long-term surveys with respect to the major reservoirs located in the Yeongsan and Seomjin river basins. A total of 45 survey sites have been surveyed four times a year from 2008 to 2017. We identified 166 zooplankton species, including 127 rotifers, 26 cladocerans, and 13 copepods. Mean population density and species number of small reservoirs were higher than those of mid and large reservoirs. Considering outliers exceeding the 90th percentile between species occupancy and mean abundance, 10 of 11 habitat generalists were rotifers, and Bosmina longirostris was the only cladoceran. Habitat specialist consisted of three species of rotifers and emerged from one to three survey sites. According to the modularity results, it was found that the survey sites covering the entire river basins were characterized into five groups, which was similar to the classification by maximum water surface areas(MWSA). The result of the eigenvector centrality showed that the size of MWSA had a greater impact on the similarity of zooplankton community structure between reservoirs than the difference in distance between reservoirs. In the case of survey points in near dam or estuary bank of Juam and Youngsan reservoirs, modularity class were separated from other internal survey points of those. Given that the zooplankton interactions may contribute to freshwater functions more than species diversity. These topological features provide new insight into studying zooplankton distribution patterns, their organization and impacts on freshwater-associated function.

• Journal of Environmental Impact Assessment
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• v.21 no.4
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• pp.553-565
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• 2012

영산강 하구에서 담수유입에 따른 저염수의 거동을 파악하기 위하여 EFDC 모델을 수행하였다. 모델의 수행은 홍수기 배수갑문 확장 전 후로 나누어 수행하였으며, 모델의 마지막 담수유입시점으로부터 16일 후 해역이 준 정상상태에 도달하기까지 저염수의 확산양상을 시간 경과순으로 살펴보았다. 그 결과, 담수유입이 멈춘 후에 저염수는 방류시점으로부터 약 6시간 경과 후에 배수갑문 전면 해역으로부터 해측으로 최대의 확산을 보였으며, 약 2~7일 후 염분의 분포 양상은 담수가 유입되기 전으로 회복되는 경향을 보였다. 한편, 배수갑문을 확장하기 전보다 배수갑문을 확장한 후에 담수유입 후 해역이 준 정상상태에 도달하는 시간이 더욱 짧았는데, 이는 시간당 방류량의 증가가 난류혼합을 강하게 하고, 해측으로 더 멀리 확산된 저염수는 외해수에 의해 보다 쉽게 혼합되기 때문인 것으로 판단된다. 따라서, 본 해역에서 일정한 양의 담수가 유입되는 경우, 저염수의 확산은 시간당 방류량이 크고 방류지속시간이 짧을수록 해역이 준정상상태에 도달하는 시간이 더욱 짧아질 것으로 사료된다.

• Water for future
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• v.16 no.2
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• pp.111-122
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• 1983

The water demand has been rapidly increased by the growth of population, industrialization, unbanization, water pollution and so on. This study carried out the seasonal pre-reserved planning for the five zones, comparing the water demand with the available water resources up to the goal year, 2001. The results of this study are as follows; 1) It is principle that the monthly water demand is supplied by the surface and ground water as the increasing tendency of it, and the deficit of water is supplemented by the water supplying capacity of dam. And water demand should be completely reserved before supplying the deficit of water. 2) The monthly and seasonal maximum deficit of water demand take place in June and summer. 3) The periods when the deficit of water demand exceeds the water supplying capacity of dam are 1984-1990, 1994-2001 in zone III. 4) To reserve the deficit of water demand in zone III, we would like to pre-construct Masan-Keumbo estuary barrage from 2001 to 1991 in Seomjin river basin, the deficit of water demand is supplied by the diversion of water from Yeongsan river basin with the developments of the ground water and small reservoirs until 1986.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.593-602
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• 2011

The estuarine area of the ecological environment had been seriously damaged by reckless developments during the past half century. The demand for management in estuarine area increased but the efficient management system did not exist. Therefore the aim of this study is to develop a GIS-based integrated DB management system by integrating the ecological environmental data of each division in estuarine area. To achieve this, the system used integrated DB. It is classified into a surveyed monitoring DB in 2010 at estuarine area of Yeongsan and GIS DB to express the spatial data. The integrated DB management system was developed using VisualBasic.NET languages and Arcobjects component for Map-based spatial analysis. Also, to improve the utilization of data, the composition of GUI(Graphical User Interface) through user needs analysis, the expression of monitoring DB, the priority of layer and the function for modular unit were defined. Ultimately the system was developed based on the defined items. GIS-based integrated DB management system can support to understand the ecological environment in estuarine area of Yeongsan river. Also it will provide the users with effective sharing and environmental management of the data. In the future study, comprehensive diagnosis for ecological environment in estuarine area and the reliable prediction need to be made by connecting modeling system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.2
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• pp.105-115
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• 2004

Growth pattern of the soft clam (Mya arenaria oonogei) was estimated based on samples collected from the Yeongsan River estuary on the southwest coast of Korea between August 1996 and September 1997. Mean density of the clam during study period was $55\;ind./m^2$ and varied monthly from 281 to $8\;ind./m^2.$ The clams from the study area ranged in age from one year to seven years, with shell lengths between 40.4 mm and 104.1 mm and biomass between 8.4 and 152.3 g in total wet weight. The spawing season was estimated to occur between September and October based upon a reduced fatness index, an indication of spawning, during these months. Burial depths increased with growth of the clams and most were found buried between 10 and 20 cm in the sediments. Significant relationships were found between shell length and shell height (SH), total wet weight, (TWt), meat wet weight (MWt), meat dry weight (DWt), ash free dry weight (AFDW) and burial depth. The von Bertalanffy growth equations of the clams were $L_t(mm)=138.98(1-e^{-0.1325(t+0.8853)})\;and\;W_t\;(gTWt)=325.93\;(1-e^{0.1325(t+0.8853)})^{2.6982}.$ These equations suggest that in their first year the clams should reach 31 mm in length with a biomass of 5.7 g in total wet weight.

• Spatial Information Research
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• v.22 no.4
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• pp.39-47
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• 2014

The Yeongsan river estuary has a serious water quality problem due to the water stagnation and it is imperative to predict the changes of water quality for mitigating water pollution. EFDC(Environmental Fluid Dynamics Code) model was mainly utilized to predict the changes of water quality for the estuary. The EFDC modeling normally accompanies the large volume of modeling output. For checking the spatial distribution of the modeling results, post-processing for converting of the output is prerequisite and mainly post-processing program is EFDC_Explorer. However, EFDC_Explorer only shows the spatial distribution of the time series and this doesn't support overlay function with other thematic maps. This means the impossible to the connection analysis with a various GIS data and high dimensional analysis. Therefore, this study aims to develop a post-processing system of a EFDC output to use them as GIS layers. For achieving this purpose, a editing module for main input files, and a module for converting binary format into an ASCII format, and a module for converting it into a layer format to use in a GIS based environment, and a module for visualizing the reconfigured model result efficiently were developed. Using the developed system, result file is possible to automatically convert the GIS based layer and it is possible to utilize for water quality management.