• Journal of the korean society of oceanography
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• 제38권2호
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• pp.80-86
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• 2003

The horizontal distributions of $^{224}Ra$ (half life=3.4 days) and $^{223}Ra$ (half life=11.3 days) were measured in surface seawaters of the Nakdong River estuary and the South Sea of Korea in April and October 2002. In order to determine these short-lived Ra isotopes, we used a delayed coincidence counter which is much more rapid and accurate than traditional methods. In an estuarine mixing zone (salinity, ~l6 ppt), the activities of $^{224}Ra\;and\;^{223}Ra$ were much greater than what would be expected from a mixture of freshwater and seawater in the Nakdong River estuary. This excess Ra may be a result of Ra desorption from fresh sediments originating from the river upstream. However, in the more open areas of the Nakdong River estuary (salinity>30 ppt) and the South Sea of Korea, $^{224}Ra\;and\;^{^{223}Ra$ activities decreased exponentially as a function of distance offshore. Using the decrease of $^{223}Ra$ with distance offshore in the South Sea of Korea, we estimated the apparent horizontal eddy diffusivities. The apparent eddy diffusion coefficients in South Sea of Korea are calculated to be approximately $3500-8000\;\textrm{m}^2/sec$.

• 한국어류학회지
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• 제17권2호
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• pp.131-141
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• 2005

본 연구는 2004년 5월부터 2005년 2월까지 합천호를 중심으로 댐 내부에서 4곳, 댐 상 하류 하천에서 각각 1곳씩 모두 6개 지점을 중심으로 어류상을 조사 분석하였다. 그 결과 모두 12과 31속 36종으로 확인되었다. 본 조사 기간동안에 출현한 어류 가운데 우점종으로는 H. eigenmanni로 전체 어류의 28.4%의 출현률을 나타내었고, 아우점종으로는 H. labeo가 24.1%였다. 또한 출현한 어류 중 생산량이 가장 높은 어종은 H. labeo로서 전체의 36.5%의 비중을 차지하였고, 다음으로는 H. eigenmanni 22.3%, C. carpio 7.5%, H. nipponensis 6.9%의 순이었다. 합천댐 일대에서 종별 출현빈도가 가장 높은 분류군은 Cyprinidae 어류가 24종으로 전체의 66.7%였고, 그 다음으로는 Cobitidae와 Centropomidae가 각각 2종씩이고, 나머지는 1종씩이었다. 본 조사 구역에서 출현하는 우리나라의 특산어종은 모두 10종, A. koreensis, C. splendidus, S. gracilis majimae, S. chankaensis tsuchigae, M. yaluensis, H. eigenmanni, N. multifasciata, L. mediadiposalis, C. herzi, O. platycephala 등이며, 이 중 H. eigenmanni와 C. herzi는 출현 개체수가 많았으나, 그 외의 종은 비교적 희소하였다. 본 합천댐에서 출현하는 어류 중에서 외래어종은 C. carpio (Israeli), C. cuvieri, L. macrochirus이었고, 우리나라의 다른 하천에서 유입된 P. fulviraco가 확인되었다.

• 한국환경과학회지
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• 제22권2호
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• pp.251-257
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• 2013

Discharge data examine the process of hydrologic cycle and used significantly in water resource planning and irrigation and flood control planning. It makes high quality discharge data, they carry out research on standard and method of discharge measurement, and equipment improvement. Now various flow meters are utilized to make discharge data in Korea. However, accuracy of equipment and exprerimental research data from measurement are not enough. ADCP(Acoustic Doppler Current Profiler) have been introduced and utilized for flow measurements since the end of 1980's. ADCP flow method is a formal method for flow measurement can easily applyd to relatively large rivers gradually recognized. This equipment can measure the non-contact three-dimensional velocity and water depth data very quickly and efficiently. Also, spatial and temporal resolution of the data is more accurate than any other flow measurement methods which measure flow rate by velocity - area measurement method. In this paper, the velocity is measured using various flow meter and verified the effectiveness by applying from the ADCP in Geum-river. Various flow meters which are med for discharge measurements are VALEPORT002, FLOW TRACKER, PRICE AA and ADCP. The average of five times flow measurement result by ADCP was $10.412m^3/s$, with a standard deviation of 0.68. The repeat test by ADCP and comparison between ADCP and other flow devices to verify the most import factor, flow measurement accuracy. In the result, repeat test of the ADCP showed similar values, flow values were similar to other velocity device results and the average error is 7.7%.

• 생태와환경
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• 제49권2호
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• pp.130-141
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• 2016

This study was conducted to elucidate the structure of river ecosystem in the watershed of the Seom River and Hoengseong Reservoir located in Hoengseong of Kangwon Province from February to October 2007. Topics of the survey were mainly rainfall, discharge, water quality in abiotic factors and attached algae, benthic macroinvertebrates, fish, birds and mammals of flora and fauna in a biotic factors, respectively. Specifically, the Seom River could be seen as a typical flow rate of the stream is controlled to the effect of the dam. Basic water qualities were great to seasonal effects, it was relatively clean. Diatom Achnanthes, Cymbella, Gomphonema, and Navicula were distributed predominantly in the periphytic algae. Benthic macroinvertebrates were mostly aquatic insects and freshwater shellfish, the aquatic insects were abundant Ephemeroptera and Trichoptera. Freshwater fish was the dominant Zacco platypus, fish species varied toward the downstream. Birds were mainly observed in four species, and species Egretta garzetta, which was distributed in a wide area of the Seom River. In mammals, Lutra lutra of Mustelidae was identified that the number of inhabit widely. In aspects of the ecological trophic level, the Seom River was maintained at a relatively stable state in the producer and the consumer relationship. The results of this study will expected to be utilized as a useful data for understanding the structure and function of the lotic and lentic ecosystems.

• 환경영향평가
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• 제9권2호
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• pp.143-153
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• 2000

This study was performed to investigate the heavy metal contents and distribution in soil, sediment, and rice from the downstream area of ManKyeong and DongJin River. Of the sites on Mankyeong river area, site M-1(Mokchon bridge) showed the highest average contents of Cd, Cr and Pb in paddy soil. In DongJin river area, site D-3(Munpo) and D-4(Gerjeonri) showed relatively high level of average contents of Cr, Pb and Zn in paddy soil. The average contents of heavy metals in brown rice from ManKyeong river area were 0.10mg/kg for Cd, 0.99mg/kg for Cr, 2.07mg/kg for Pb, 4.44mg/kg for Cu and 32.03mg/kg for Zn while those in brown rice from DongJin river area were 0.14mg/kg for Cd, 0.74mg/kg for Cr, 1.78mg/kg for Pb, 4.57mg/kg for Cu and 33.60mg/kg for Zn. Zn showed the highest transportation-rate from paddy soil to brown rice while Pb showed the lowest. From the results of heavy metal analysis in sediments, the average contents of Cd, Cr, Pb and Cu were generally high in site M-5(Euonri) and D-4(Gerjeonri), the most downstream sites in Mankyeong river and DongJin river, respectively.

• 환경영향평가
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• 제22권4호
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• pp.319-327
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• 2013

This study was conducted to identify runoff characteristics of pollutants using flow duration curve(FDC) and load duration curve(LDC) in Youngbon A watershed during 2009~2011. A flow rate and pollutant load in the study watershed were estimated by equation of stage-discharge and discharge-loads rating curve. From these methods, BOD, T-N, and T-P have evaluated whether water quality standards would have attained. Results showed that BOD loads of about 50% plotted above the LDC, while T-N and T-P loads of about 50% plotted below the curve. It means that BOD of about 50% have exceeded the water quality criteria, while T-N and T-P of about 50% have complied with the water quality standards. Meanwhile, BOD, TN and T-P loads plotted above the LDC of low flows, implying that they were more affected by point pollution sources than nonpoint pollution sources in the study watershed.

• Ecology and Resilient Infrastructure
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• 제6권1호
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• pp.12-22
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• 2019

본 연구에서는 팔당호 내 주요지점에서 수심별 연속 수리 및 수온 조사를 수행하여 팔당호의 시공간적 물순환 특성을 파악하고자 하였다. 이포보와 청평댐에서의 수온 및 방류 패턴의 차이로 인하여 팔당호 내 북한강 및 남한강 구간에서의 흐름 및 수온 변동특성이 상이하게 나타났다. 수직혼합기에는 북한강과 남한강 구간의 전 층에서 하류방향 흐름이 우세하게 나타났다. 성층형성기에 이포보 방류수의 수온이 청평댐 방류수의 수온보다 높았으며, 이로 인해 북한강 하류 구간에서 표층은 상대적으로 고온수가 위치하여 상류방향 흐름으로 배수 현상이 나타나고 수렴대가 형성되었다. 남한강 하류 구간은 중층과 저층에서 저온수가 분포하여 상류방향 흐름이 나타나고 표층과 혼합되기 어려운 이층류 구조를 나타내었다.

• 한국지리정보학회지
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• 제16권1호
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• pp.15-25
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• 2013

국가하천에 대한 하천대장, 하천측량도 및 부도 등 관련 정보들을 표준화하여 구축함으로써 관련 업무 활용 및 대국민 서비스 등을 실시하기 위해 국토해양부에서는 지난 2000년도부터 하천관리지리정보시스템(RIMGIS; River Information Management GIS)을 구축하여 운영 중에 있다. RIMGIS는 그 동안 정보환경 변화에 능동적으로 대응하기 위해 여러 차례 개선되었으며, 최근 스마트 리버 하천정보 서비스 및 관련 자료가 방대해짐에 따라 빅데이터를 효율적으로 관리하기 위한 개선이 필요한 실정이다. 본 연구에서는 RIMGIS의 현황 파악, 개선방향 도출, 데이터베이스를 재설계, 배포프로그램 개발 및 하천종합정보시스템 제안을 통해 정보환경 변화에 대응해 향후 스마트 리버 하천정보 서비스를 제공하기 위한 방안을 제시하고자 한다. 따라서, RIMGIS의 활용성을 강화하기 위해 속성정보의 엔터티간 연관관계를 구분할 수 있는 유일키와 외부키 등과 하천표준 데이터베이스 관점에서 테이블간의 위상관계를 정립하여 속성정보 DB의 구성과 정보관리를 위하여 연관관계도도 새롭게 제시하였다. 아울러, 하천관리 패러다임 변화에 대응 가능한 하천관련 정보의 효율적인 관리와 이용 체계 수립을 통해 현재 공급자 중심의 시스템 운영을 수요자 중심으로 확대하기 위한 방안을 도출하였다.

• 상하수도학회지
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• 제21권1호
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• pp.113-122
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• 2007

Experimental studies were performed to investigate speciation and leaching potential of heavy metals(Cu, Cd, Pb Zn, Ni) in ten sediment samples collected from Nakdong River. Acid Volatile Sulfide (AVS) and Simultaneously Extractable Metals (SEM) measurements were used to estimate heavy metals that can be leached under anaerobic conditions. Sequential Extraction Procedure (SEP) and Toxicity Characteristic Leaching Procedure (TCLP) were used to characterize speciation and leaching potential of heavy metals under aerobic conditions. The results show that total concentrations of Cu, Zn and Ni were relatively high in the sediments from points Seongseo industrial complex stream (upper stream) (D), Seongseo industrial complex stream (midstream) (E), Dalseo stream (F), and Nakdong river estuary (J), and that Cd concentrations were higher in all sampling points except for Goriung Bridge (G) and Soosan Bridge (H). SEM and AVS analyses reveal that samples from points Ilsun Bridge (A), Namgumi Bridge (C), and Soosan Bridge (H) have potential of heavy metals leaching, although leachable concentrations are relatively low. The leaching potential of heavy metals in other points was low because of higher concentrations of AVS than SEM. SEP results show that more than 50% of Cu, Zn and Ni were present in residual fraction, which means these metals are less amenable to leaching in anaerobic conditions. On the other hand, more than 50% of Pb and Cd were extracted during the first through third step of the SEP, which means substantial fraction of these metals can be leached upon changing of redox conditions. TCLP tests predict that leaching potential of heavy metals was generally low, which is consistent with the results obtained by AVS and SEM measurements.

• 한국물환경학회지
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• 제31권2호
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• pp.110-119
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• 2015

The construction of the eight large weirs in the Nakdong River, the second largest river in Korea, caused big changes in the physical environment of the water system. Algal communities and their correlations with environmental factors, mainly nutrients were studied at five weir areas in the Nakdong River from 2010 to 2013. Water quality, hydrodynamics and algal composition were investigated. Results showed that flow velocities were reduced compared with that before weir construction near the areas where are located in the mid and upstreams of the Nakdong River. A seasonal algal community succession was observed and it was mainly correlated with temperature and phosphorus. Diatoms were dominated from winter to spring months and massive diatomic blooms of Stephanodiscus sp. occurred early in March during survey period. Cyanobacterial blooms of Microcystis sp. occurred from July to September 2013 and was preceded by the lower total phosphorus concentration of $0.05mg\;L^{-1}$. The correlations between total phosphorus concentrations and algal abundances were not significant during the survey periods. However, significant correlation with cyanobacteria was found in the period of weir construction after only at the GG survey site and blooms periods of 7 times in the survey sites, and its correlation coefficients were 0.53 (p<0.001) and 0.42 (p<0.01) respectively. When algal bloom was observed, partially low nutrient concentration was observed in the Nakdong River. In conclusion, partially low nutrient concentration which may result from algal bloom was observed, and we presume it caused the reduction of algal abundunces.