• Journal of Korea Water Resources Association
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• v.53 no.1
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• pp.57-70
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• 2020

This study is to establish the situation of inter-basin transfer from Seomjin river basin to Yeongsan river basin using SWAT (Soil and Water Assessment Tool). Firstly, the SWAT modeling was conducted for each river basin. After, the inter-basin transfer was established using SWAT reservoir operating parameters WURESN (Water Use Reservoir Withdrawn) and inlet function from Juam dam of Seomjin river basin to Gwangju stream of Yeongsan river basin respectively. Each river basin was calibrated and validated using 13 years (2005~2017) data of Seomjin- Juam dam reservoir storage (JAD), release, transfer and Yeongsan-Mareuk (MR) stream gauge station. The results of root mean square error RMSE, Nash-Sutcliffe efficiency NSE, and determination coefficient R² of JAD were 2.22 mm/day, 0.62 and 0.86 respectively. The RMSE, NSE, and R² of MR were 1.38 mm/day, 0.69 and 0.84 respectively. To evaluate the downstream effects by the transferred water, the water levels of 2 multi-function weirs (SCW, JSW) in Yeongsan river basin and the Gokseong (GS) and Gurye (GR) stream gauge stations in Seomjin river basin were also calibrated. The RMSE, NSE, and R² of SCW, JSW, GS and GR were 1.49~2.49 mm/day, 0.45~0.76, 0.81~0.90 respectively.

• Korean Journal of Environmental Biology
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• v.22
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• pp.47-53
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• 2004

Among the phthalic esters, di-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP), which are categorized endocrine disrupting chemicals, account toy up to 80％ of the world production. Nine phthalic esters were quantitatively determined in water and in sediment samples from Gawngyang Bay and Seomjin River estuary. This might be the first report in contamination of phthalates in the marine environment of Korea. DBP and DEHP were detected with the high concentration and high frequency, while the other phthnlic compounds were below the detection limits. The aveyage concentyations of DBP and DEBP in sediment from Gawngyang Bay were 33.8 ng g$\^$-1/ and 67.4 ng g$\^$-1/ on a dry weight basis, respectively. The concentrations in surface watey from Seomjin River estuary were in the range of 62.7∼333.8 ng L$\^$-1/ for DBP and 25.6 ng L$\^$-/∼116.1 ng L$\^$-1/ for DBHP. In sediments from Seomjin River estuary, DBP ranged 9.1∼149.3 ng g$\^$-1/, and DEHP 46.3∼156.3 ng g$\^$-1/. Phthalic esters concentrations found in Seomjin River estuary were much less than those in other rivers in Korea. Distribution pattern of DBP and DEHP concentrations in Seonliin River estuary indicates that both compounds aye introduced to Gwangyang Bay through run-off.

• Korean Journal of Environmental Biology
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• v.30 no.4
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• pp.319-327
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• 2012

This paper was the result of investigation on fish fauna of natural estuary at Seomjin River, Korea. The total number of fish species collected in this study was 68 species belonging to 26 families. Dominant species in number was Acheilognathus majusculus (relative abundance: 37.4%), subdominant was Tribolodon hakonensis (10.5%). There were seven migrating fishes including Anguilla japonica and T. hakonensis. There were twenty Korean endemic species including Acheilognathus koreensis and Acheilognathus somjinensis. Thirty five species belonging to eight families were collected in upper part of river that dominant species was A. majusculus (38.2%). Thirty seven species were collected in lower part of river that dominant species was A. majusculus (48.5%). Thirty four species were collected in near estuary that dominant species was T. hakonensis (42.6%). In the comparison result of condition factor for several main species populations of Seomjin River were better than Nagdong River populations having estuary barrage. It was considered that almost fish populations of mid-to lower Seomjin River without estuary bank have stable life with natural environment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.199-206
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• 2001

Behavior of nutrients along the salinity gradients in the Seomjin River estuary was investigated in March July, September and November, 1999. Sampling sites were set based on the surface salinity during each cruise rather than geographic locations. The results suggest that source of nitrate and silicate was the Seomjin River discharge, while that of nitrite and phosphate was waste disposal from the Gwangynng Bay near the mouth of Seomjin River estuary. Ammonia was supplied inside the estuary at the region about $6\~8$ km far from Nancho Island. Strong removal behavior of some nutrient such as ammonia, phosphate and silicate was observed at $5\~15$ psu salinity area in November, where high concentrations of $chlorophyll\;a\;(>8{\mu}g/L$) occurred. High N : P ratios and entirely removal of phosphate at chlorophyll a peak region suggest that phosphate is the limiting factor for phytoplankton growth. Relatively high ratios of Rb to Ra (Rb: Fluorescence before acidification, Ra: Fluorescence after acidification) at $5\~15$ psu salinity region in November indicate that phytoplankton were in good physiological condition.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.402-410
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• 2013

In this study, to identify ichthyofauna of the Seomjin River, which has no barrage at estuary, and to estimate effect of estuary barrage, fish sampling was conducted at 16 study sites in mainstream of the Seomjin River from 2010 to 2012. A total of 54 species classified into 17 families were collected. Cyprinidae was the dominant family and Zacco platypus (relative abundance, RA: 47.8%) was identified as the dominant species. In total, 17 Korean endemic species (31.5%) were collected, and it is higher than the average endemic rate of Korean peninsula (22.5~25.9%). Although the relative abundance of exotic species (1.1%) was low, it is higher than the past studies (2002: 0.0%, 2009: 0.4%). Dominance index of freshwater region (St.4~St.16) was relatively higher than estuary (St.1~St.3), because Z. platypus showed high relative abundance at freshwater region. But diversity and evenness index showed contradictory results, as estuary was higher than freshwater region. The ratios of sea fish, peripheral freshwater fish and economic fish, and diversity index are higher than the Nakdong River, the Yeongsan River and the Geum River. In conclusion, to conserve the value of the Seomjin River ichthyofauna, continuous monitoring is necessary.

• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.212-220
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• 2022

An estuary is a water ecosystem with a high abundance of the species diversity, due to a variety of complex physicochemical factors of the area where freshwater and ocean mixed. The identification of Corbicula species in the estuary environments is difficult because of various morphological characteristics. In this study, we provide taxonomic information on Corbicula species with taxonomic difficulties using morphological and genetic analysis. This study was conducted on clams from the Seomjin River-Gwangyang Bay, one of the major production area of marsh clam in Korea. As a result, we characterized Cytocrome C Oxidase subunit I (COI) sequences of the Corbicula. The 636 bp nucleotide sequences of COI have 98% homology among Corbicula species collected from 2 sites of Seomjin River-Gwangyang Bay. The phylogenetic analysis with 17 species of Corbicula indicated that most of the species collected from Seomjin River-Gwangyang Bay were brackish water clam (Corbicula japonica), and only one Asian clam (Corbicula fluminea). The evolutionary distance between C. japonica and C. fluminea was less than 0.003. Therefore, it was confirmed that C. japonica is phylogenetically closely related to C. fluminea. In 9 species of Cyrenidae, phylogenetic tree was classified into three lineages. These results will be used as an important data for an identification of clam species by providing genetic information for Corbicula species with a morphological diversity.

• The Korean Journal of Zoology
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• v.19 no.4
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• pp.171-178
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• 1976

A new species of Cobitid fish, Cobitis longicorpus is described, based upon many specimens from several tributaries of the Seomjin River situated in the south western part in Korea. Cobitis longicorpus was previously reported as the crossband type of C. taenia by all ichthyologists in Korea. This is distributed in the Seomjin River and characterized by the distinctive cross-band color pattern, the black spots at the back of its opercula, and the structure of lamina circularis in male.

• Journal of Ecology and Environment
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• v.37 no.4
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• pp.209-216
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• 2014

This study was undertaken to suggest an effective fisheries resources management system by using stock assessment and potential yield analyses of crucian carp population in the mid-upper system of the Seomjin River. Fieldwork was conducted seasonally from 2008 to 2009 in the mid-upper system of the Seomjin River. The stock assessment was carried out by the swept area method and the potential yield was estimated by improved fisheries resource potential estimation system based on the Allowable Biological Catch. Also, the yield-per-recruit analysis was used to review the efficient management implication of the resource, Carassius auratus. As a result, the age at first capture ($t_c$) was estimated as 1.468 year, converted body length (BL) was 10.8 cm. Meaning the current fishing intensities, the instantaneous coefficient of fishing mortality (F) was $0.067year^{-1}$, and the yield-per-recruit analysis showed that the current yield per recruit was estimated to be 15.999 g with F and $t_c$. The instantaneous rate of fishing mortality that provides for Allowable Biological Catch ($F_{ABC}$) based on the current $t_c$ and F was estimated as $0.618year^{-1}$. Therefore, the optimum fishing intensities could be achieved at the higher fishing intensity for Carassius auratus. The calculated annual stock of C. auratus was estimated as 7,608 kg, and the potential yield was estimated as 343 kg with $t_c$ and F at the fixed current level. Using yield-per-recruit analysis, if F and $t_c$ were set at $0.618year^{-1}$ and 2 year, the yield per recruit and total allowable catch would be predicted to increase to 62 g and 2,531 kg by about 3.9 times and 7.3 times, respectively.

• Korean Journal of Environmental Biology
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• v.20 no.2
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• pp.152-157
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• 2002

The fauna of freshwater fish and the structure of fish community were investigated from March to October in 2001 at six stations in the middle reach of the Seomjin River, Gokseong-gun. The collected fishes (1,786 individuals) were identified into 30 species of 22 genera belonging to S families. Of them, cyprinid fish occupied 26 species, only one species (Rhinogobius brunneus) was secondary freshwater fish. Dominant species was Zacco platypus (dominance index: 24.2%) and subdominant species was Pungtungia herzi (10.7%). The endemic species of Korea were 11 species including Rhodeus uyekii (36.7%) about the ichthyofauna. In estimation of water quality by diversity indices, the general conditions of water quality of all survey times and all stations were relatively fine $(\beta$-mesosaprobic, diversity index: 2.70). But four survey sites except St. 2 and St. 3 showed severe water pollution with one or move times in total survey periods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2B
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• pp.93-101
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• 2012

HEC-ResSim, reservoir operation model, is applied to Seomjin river dam in order to establish a rational method for water supply and flood control by dam operation. In order to minimize downstream flood damage for Seomjin river basin and adjacent regions, reservoir routing is applied to several frequency flood events within the framework of rainy seasonal operation rule and then the characteristics change of hydrological behavior for the downstream of study area is investigated in depth. Its quantitative efficiency and estimation method is evaluated on the basis of the adjustment scheme of conservation water surface elevation for flood control and water secure; reservoir routing considering preliminary release and variable restricted water level; and its effect to water supply; and downstream flood-duration analysis.