• 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 Environmental Biology
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• v.35 no.4
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• pp.549-556
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• 2017

Rivers continuously transport terrestrial organic carbon matter to the estuary and the ocean, and they play a critical role in productivity and biodiversity in the marine ecosystem as well as the global carbon cycle. The amount of terrestrial organic carbon transporting from the rivers to ocean is an essential piece of information, not only for the marine ecosystem management but also the carbon budget within catchment. However, this phenomenon is still not well understood. Most large rivers in Korea have a well-established national monitoring system of the river flow and the TOC (Total Organic Carbon) concentration from the mountain to the river mouth, which are fundamental for estimating the amount of the TOC flux. We estimated the flux of the total terrestrial organic carbon of five large rivers which flow out to the Yellow Sea, using the data of the national monitoring system (the monthly mean TOC concentration and the monthly runoff of river flow). We quantified the annual TOC flux of the five rivers, showing their results in the following order: the Han River ($18.0{\times}10^9gC\;yr^{-1}$)>>Geum River ($5.9{\times}10^9gC\;yr^{-1}$)>Yeongsan River ($2.6{\times}10^9gC\;yr^{-1}$)>Sumjin River ($2.0{\times}10^9gC\;yr^{-1}$)>>Tamjin River ($0.2{\times}10^9gC\;yr^{-1}$). The amount of the Han River, which is the highest in the Korean rivers, corresponds to be 4% of the annual total TOC flux of in the Yellow River, and moreover, to be 0.6% of Yangtze River.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.113-122
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• 2014

This study was conducted to clarify the community characteristics of wintering waterbirds in Geum River from September, 2011 to March, 2012 (1st) and from September, 2012 to March, 2013 (2nd). 63 species of waterbirds including raptors were observed during the survey. 50 species of 188,673 individuals recorded during the first survey, and 56 species of 116,611 individuals were recorded during the second survey. The dominant species was high dominance dabbling ducks by Baikal Teals, Mallards, Spot-billed Ducks, Greater White-fronted Geese, Black-tailed Gulls and Common Shelducks. We classified the wintering waterbirds into 9 taxa based on the similar ecological characteristics and analyzed the correlation with temperature. As a result, dabbling ducks, diving ducks and raptors showed positive correlation and herons and waders showed negative correlation. Geese, swans and dabbling ducks were high habitat utilization ratio at the Geumgang estuary barrage upstream area, and diving ducks, herons, waders and gulls were high habitat utilization ratio at the Geumgang estuary barrage downstream area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.382-388
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• 2014

This study selected five observational stations in the normal direction of Jinu-do(island) shoreline and observed water temperature, electrical conductivity and pressure from March, 2012 to January, 2013(about 11 months) and attempted to see the variation characteristics of ground watertable. This study wants to know : 1) External environment force factors(tide, climate, wave etc.) affecting ground watertable variation through time series and correlation analysis. 2) Spatial variations of ground watertable and electrical conductivity change by storm event. First, we found that the station at the intertidal zone was strongly affected by wave and tide level and the stations at sand dune and vegetation zone was affected by precipitation and tide level through time series data and correlation analysis. Second, during the storm event, we found that ground watertable and electrical conductivity are stabilized at the start line of sand dune and vegetation zone and transition zone between freshwater layer and seawater layer exists in the experiment area and is about 50~70 m from coastline of the south side of Jinu-do(island).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.1
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• pp.45-56
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• 2007

Direct estimation of the pollutant load(PL) should be carried out by the data filling in the missing intervals using an appropriate method because it is impossible in which the flow discharge(water quantity) or water quality(WQ) time-series data set have the missing intervals. In this study, the several methods estimating the water quality in the missing periods are suggested and the WQ and pollutants load change patterns are compared and evaluated based on the reproducible degree of the available data change patterns. The most appropriate method is finally suggested and the contribution factor deciding the influence degree and the PL characteristics of the river estuary is also suggested. Based on the PL estimation results using the several methods, the interpolation method considering the fluctuation of the available WQ data is shown to be most efficient. The PL patterns of the Han river estuary is classified as the discharge-dominated type. The data filling process is inevitable and the WQ estimation using the efficient and effective method should be carried out in order to estimate reasonable PL.

• Journal of Environmental Impact Assessment
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• v.16 no.6
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• pp.421-432
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• 2007

To investigate temporal and spatial variations of hydrodynamics and environmental conditions in Gyeonggi Bay, including Han River estuary, numerical experiments were performed using 3-dimensional fine grid numerical ocean model. The model successfully reproduced the physical phenomena already known in Gyeonggi Bay where tide and fresh water discharge are dominant forcings. The calculated harmonic constants of tide and tidal current agreed well with those of observations at nine tide stations and two tidal current stations. Tidal asymmetries along the Yeomha Waterway, mainly caused by non-linear effect, were well reproduced and agreed well with observations. Time series of salinity at four stations(A, B, C and D) and horizontal distributions of monthly averaged salinity show that Gyodong and Seokmo Waterways play an important role in fresh water discharge into the Gyeonggi Bay rather than Yeomha Waterway.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.206-209
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• 2010

A specimen of Redigobius bikolanus (29.0 mm SL) belonging to the family Gobiidae was collected by a hand net from the estuary of Changgo-cheon (river) in Andeok-myeon, Jeju Island, Korea. This specimen was characterized by having 26 lateral line scales, 7 predorsal scales, 7 transverse scales, anterior oculoscapular canal, preopercular canal, and four black spots between origin of anal fin and lower origin of caudal fin. The morphological characteristics of the specimen well matched those of Redigobius bikolanus previously reported. Thus, we newly add this species to the list of Korean fish fauna and propose its new Korean name, "Jeom-bak-i-mang-duk".

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.208-208
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• 2011

하구는 하천의 담수와 염수가 교차되고 혼합되는 기 수역으로서 수생 생태계의 중요한 서식처이며 바다와 하천의 중요한 생태통로가 되고 있다. 국내에서는 4대 하천 중에서 한강하구가 유일하게 하구 둑이 없는 자연하구이며 나머지 대하천은 둑으로 인해 담수와 해수의 자연스러운 흐름이 제한되고 생태적인 연결이 단절된 형태이다. 한강하구에는 대규모 습지가 분포하고 있으며 특히 장항습지는 종단길이 약 7.5km, 폭 최대 500m에 달하는 대규모 습지로서 고라니를 비롯한 동물과 줄, 선버들을 비롯한 식물의 대규모 군락이 분포하는 등 생태적 가치가 높은 지역이다. 본 연구에서는 한강하구의 장항습지와 산남습지를 대상으로 특정구간의 물리적 특성, 식생의 분포특성을 파악하고 연관성을 분석하고자 하였다. 이를 위해 1차적으로 포괄적인 현장조사를 통해 전체 식생군락과 분포를 파악하고 특징적인 식생군락을 선정하였다. 2차적으로는 선정된 줄 및 선버들 군락지를 대상으로 토양단면, 토양입경을 분석하고, 새섬매자기 군락지를 대상으로 측량을 실시하였다. 3차적으로는 대상 군락의 지하수위를 측정하여 상호관계를 분석하였다. 이 결과는 우선 한강하구의 지역적 특징에 국한되지만 향후 타 지역과의 비교연구가 수행된다면 대상 식생과 물리적 생장조건과의 정량적인 관계가 도출될 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1770-1774
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• 2010

하구는 담수와 해수가 만나 넓은 갯벌과 기수역을 형성하여 각종 생물의 서식지이자 어류의 산란지로 이용되는 생태학적으로 중요한 지역이다. 특히 한강 하구는 국내 4 대강 가운데 유일하게 하구둑이 설치되어 있지 않아 조수의 출입이 자유롭고 민간인 접근이 통제되어 있어 자연적인 하천지형과 기수역 생태계가 비교적 잘 보전된 구역이다. 본 연구의 모의영역은 한강 하류부로 상류 경계단은 행주대교, 하류 경계단은 전류단 수위표가 위치한 경기도 연천군 전곡읍 전곡 사랑교 부근으로 설정하였다. 지형자료는 한국건설기술연구원에서 2009년 8월 홍수사상 전 후에 대해 측량한 자료를 사용하였다. 한강 하구역에 대한 지형 격자를 구성하기 위하여 RAMS 전후 처리기인 RAMS-GUI를 사용하였으며, 구성된 지형 격자의 절점 수는 2,354개, 요소 수는 2,145개로 삼각요소와 사각요소가 혼용되어 있다. 구성된 격자망을 이용하여 2차원 하상변동 해석 모형인 SED-2D 모의를 통해 홍수사상에 의한 한강 하구부의 하상변동을 살펴보았다. SED-2D 모형은 미국 육군 공변단의 WES와 미 연방 도로국이 연계하여 개발되어 현재 국내외 2차원 하천해석에서 가장 널리 사용되고 있는 모형 중 하나이다. 하상변동 해석모형인 SED-2D를 통해 모의된 하상 변동량을 실제 측량된 홍수 전 후의 지형자료와 비교함으로써 모형의 성능을 분석하였다. 분석결과 SED-2D 모형의 경우 침식에 의한 하상변동이 모의되지 않았지만, 전반적인 하상변동 경향을 살펴볼 수 있음을 알 수 있었다.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.99-104
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• 2003

This study investigated the yearly variation of pollutant loads outflowing from six watershed of Yeong-il Bay and compared the relationship of pollutant load and water quality, and estimated the Inner productivity of Yeong-Il Bay by using ${\Delta}COD$ method which analysis nonlinear process of water quality. As the estimated results for the pollutant loads of Yeong-Il Bay, total COD load outflowing from Hyeong-san river in flood season(summer) of 2001 year was 2275.0 kg/hr and in dry(low water) season(winter) 852.8 kg/hr, respectively. Load quantity in flood season was about 2.67 times than that in dry season. And as the calculated results of the net-flux of water for seven divisions, it showed that the net-flux of water increased for the divisions of the north coast and inner sea of Yeong-Il Bay but decreased for the south coast. On the contrary, for the cases which water quantity increase from land, the net-flux of water in estuary front of Hyeong-san river decreased but outflowing quantity of that though division of the south coast of Homi-got increased. Finally, this study compared the Inner productions for flood and dry season of Yeong-il Bay by using ${\Delta}COD$ method.