• Korean Journal of Ecology and Environment
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• v.34 no.3 s.95
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• pp.141-152
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• 2001

Abundance of autotrophic picoplankton (APP) and their contribution to phytoplankton biomass were assessed in seven brackish lagoons and five freshwater reservoirs in the summer season. Phycocyanin-rich picocyanobacteria dominated APP in lagoons, while phycoerythrin-rich picocyanobacteria dominated APP in freshwater reservoirs. The cell density of APP ranged from $3.6{\times}10^3$ to $5.0{\times}10^6\;cells/ml$ (median $2.5{\times}10^5$) in brackish lagoons and from $3.8{\times}10^4$ to $3.6{\times}10^5\;cells/ml$ (mdian $1.3{\times}10^5$) in reservoirs. Carbon biomass ranged from 1.0 to $1,385.0\;{\mu}gC/L$ in lagoons and from 15.3 to $128.2\;{\mu}gC/L$ in reservoirs. APP cell density in Lake Kyungpo was over $10^6\;cells/ml$in all three surveys, which is one of the highest values recorded in all over the world. During the thermal stratification in Lake Soyang, the maximum abundance of APP and their maximum contribution to phytoplankton biomass were observed near the thermocline. This study showed that APP sometimes can contribute significantly to phytoplankton biomass both in lagoons and reservoirs with the range from 0.1 to 85.0%. APP which have been overlooked in the past studies appears to be important primary producers in Korean lake ecosystem.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.37-46
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• 2005

From 2000 to 2004, the research was carried out at Naerin-cheon and Inbook-cheon, the upper streams of Soyang Lake, to study the relationship between precipitation and eutrophication-causing water pollutants, BOD, T-N and T-P. During the five years, the amount of flowing water was measured, and the water quantity was examined under different precipitation levels. From the observation, outflow patterns of the water pollutants and changes in the water quality factors at the time of rainfall were clarified. In addition, estimation of the unit load was made for each stream; for Naerin-cheon at the time of rainfall, we estimated BOD to be $1,112kg/km^2/year$, T-N to be $2,077kg/km^2/year$, and T-P to be $223kg/km^2/year$; for Inbook-cheon at the time of rainfall, we estimated BOD to be $1,229kg/km^2/year$, T-N to be $1,565kg/km^2/year$, and T-P to be $255kg/km^2/year$. For the time of no rainfall different estimation was made; for Naerin-cheon, we estimated BOD to be $2,403g/km^2/day$, T-N to be $5,004g/km^2/day$, and T-P to be $53g/km^2/day$; and for Inbook-cheon, we estimated BOD to be $1,550g/km^2/day$, T-N to be $2,283g/km^2/day$, and T-P to be $42g/km^2/day$.

• Journal of the Korean Geophysical Society
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• v.9 no.1
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• pp.1-6
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• 2006

To remove ringing and increase vertical resolution of GRP data, signature deconvolution was applied to GPR data obtained using a 100 MHz antenna in the Soyang Lake. The signature was extracted through stacking reflection signals from the lake bottom. Results of this deterministic deconvolution was compared with those from the conventional Wienner method. Due to increased vertical resolution, both deconvolution methods are able to resolve three or more layers in an apparent single layer on the input data. However, identification of reflection boundaries from ringing is not easy due to poor definition in the output data of the Wienner filter. On the contrary, the signature deconvolution greatly enhances both vertical resolution and definition of reflection boundaries, showing detailed internal stratigraphic features of the three sedimentary layers. Since extraction of signature at various depths is possible, this deconvolution method can be appled effectively to unstationary GPR data.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.502-502
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• 2023

지난 140여년(1880~2022)간 지구의 연평균 기온은 약 1.5℃ 상승하였다. 이에 따라 폭염, 홍수, 가뭄 등 이상기후 발생이 급증하고 있으며, 생태계가 급격히 변화하여 담수호의 산소량 또한 급속히 감소하고 있다. 소양호는 총길이 60 km, 유역면적 2.703 km², 최대저수량 29억톤으로, 유역면적은 북한강 유역의 25%에 달하며 북한강 상류에 위치하고 있는 국내 최대의 인공호이다. 따라서 소양호 유역의 관리는 북한강 유역의 수질 관리와 수도권 수자원 공급의 핵심 중 하나라고 볼 수 있다. 그러나 기후변화에 따라 소양호의 성층현상에도 변동이 생겼을 것으로 판단되고 있다. 호소의 성층현상은 수심에 따른 온도의 변화로 발생하는 현상으로, 성층현상이 심하면 유체는 연직운동이 제한되고 상대적으로 수평방향 운동이 활발해진다. 소양호는 수심이 매우 깊으며, 열용량이 크기 때문에 여름에 성층이 형성되는 온대일순환호(warm monomictic lake)로 분리된다. 성층현상이 심하면 호소 하부의 저층에서는 용존산소가 거의 없어 혐기성 상태가 되고, 침전된 유기물이 혐기성 미생물에 의해 분해되기 때문에 수질은 크게 악화된다. 따라서 본 연구는 30년간의 소양호의 수온과 DO의 변동을 분석하여 성층현상의 변동성을 파악하고자 하였다. 이에 따라 약 30년간(1993년 1월~2022년 12월) 0~90 m까지 측정한 수온, DO 데이터를 이용하였다. 데이터는 매달 최소 1회~최대 5회 측정된 자료 중 가장 수심이 깊게 측정된 날의 자료를 이용하였다. 1월과 2월의 데이터는 동절기로 인해 소양호 조사를 실시할 수 없어 제외하였다. 수온의 경우 30년간 서서히 증가하는 경향을 보였으며 0~90m 전반에 걸쳐서도 대체로 증가하는 경향을 보였다. 또한 6월에 성층현상이 더 심해지고, 겨울에는 연직운동이 감소하는 모습을 보였다. DO의 경우 용존산소가 중층에서 최저를 보이는 Metalimnetic oxygen minimum을 보였으며, 2008년까지는 거의 매년 농도 2.0mg/L 이하인 달이 있었으나 그 이후에는 회복되어 대부분 2.0 mg/L 이상을 보였다. 그러나 심층의 경우에는 2014년부터 DO 농도 3 미만으로 떨어지는 경우가 증가하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1551-1555
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• 2006

효율적인 댐 운영 및 관리를 위하여 퇴사유입으로 인한 저수용량의 감소에 대한 정량적인 분석이 필수적이다. 본 연구의 대상지인 소양호는 소양강댐이 준공된 1973년을 기준으로 매 10년마다 세부측량을 통한 퇴사량 조사가 실시되고 있다. 기존의 조사에서는 장기적인 퇴사량 예측을 위해 U.S.B.R의 경험적 면적감소법과 90년대 초반부터는 1차원 모형인 HEC-6가 적용되어 왔다. 그러나 기존의 방법은 저수지 내 퇴사의 횡방향 분포는 고려할 수 없다는 단점이 있다. 이를 보완하기 위해 저수지 횡단방향으로의 퇴적과 세굴을 모의할 수 있는 2차원 이상의 모형이 적용되어야 한다. 본 연구에서는 소양호의 장래퇴사분포를 모의하였다. 현재 실무에서 주로 이용되고 있는 HEC-6 모형과 2차원 수치모형인 HSCTM2D(Hydordynamics, Sediment and Contaminant Transport Model)모형 및 SMS-SED2D 모형을 비교한 후 SMS-SED2D 모형을 소양강댐 유역에 적용하였다. 또한 모형의 매개변수 보정을 위하여 퇴사량 조사용역으로 수행된 1983년과 2005년의 실측횡단자료를 이용하였으며, 향후 소양강댐의 관리를 위한 기초자료로의 활용을 위하여 댐 축조후 50년, 100년후의 저수지내 퇴사분포를 모의하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.296-299
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• 2003

In this paper, an underwater acoustic digital transceiver is designed and implemented by a multiple DSPs system. We have designed a QPSK transmitter based on look-up table and 13-symbols Barker code is used for frame synchronization. Channel distortions are compensated by a wide-band beamformer based on FIR filter and an adaptive equalize. with RLS algorithm. Uniform linear array (ULA) with four elements is used for the spartial signal processing. 1/2 convolutional code and Viterbi decoder are implemented to overcome time-varying multi-path fading. Also, we show experimental results in the underwater anechoic basin at KRISO/KORDl and Goseong, Donghae and Soyang lake of Kangwon-do.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.199-203
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• 2011

본 논문은 북한강 상류의 국내 최대 다목적댐인 소양호 유역을 대상으로 하였으며, 오염물질 항목에 대한 배수구역별 오염부하량을 산정하여 유황변화에 따른 오염부하량의 유달특성을 관찰하였으며, 배수구역별 유달오염부하량의 기여율을 산정하였다. 배수구역의 오염부하량 유달특성을 관찰한 결과 BOD, SS, T-P의 경우 인북천 유역에서 높은 유달률을 보였으며, T-N의 경우 내린천 유역과 합강 유역의 시가지에서 높은 유달률을 보여 배수구역별 오염총량관리를 위한 중점관리 수질항목을 제시할 수 있었다. 다음으로 배수구역별 유황변화 및 계절변화에 따른 오염부하량의 기여율을 산정한 결과, 전반적으로 BOD와 T-P의 경우 인북천 유역에서 높은 기여율을 보였으며, SS는 강우기간에는 내린천 유역, 비강우기간에는 인북천 유역에서 T-N은 내린천과 북천 유역에서 높은 기여율을 보였다. T-N과 T-P는 호소수 부영양화 조절을 위한 제한 영양소임을 고려할 때 본 유역에 대한 오염원의 집중적인 관리가 필요한 것을 알 수 있다.

• Journal of Korean Society on Water Environment
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• v.29 no.1
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• pp.81-87
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• 2013

Changes of organic carbon after the entrance into dam reservoirs were investigated using water samples collected in May, September, and October in 2010 from the inflow sites and the outlets of four selected dam reservoirs-Soyang, Chungju, Chungju regulation, and Uiam. Increase of refractory dissolved organic carbon (R-DOC) was observed only for large dam reservoirs with long residence times whereas the trend was not found for relatively small reservoirs. The effects of residence times on organic carbon changes were further confirmed by significant positive correlations between monthly residence times and the relative increase of either dissolved organic carbon (DOC) or R-DOC concentrations. Comparison of spectroscopic characteristics of DOC revealed that the changes in the large reservoirs in May might result from in-lake processes. The inflow of terrestrial sources of DOM during storms appears to largely affect the DOC quality of the large reservoirs for the rest of the sampling periods. The mechanism, however, did not fully explain the behaviors of DOC for the small sized reservoirs. Our combined results suggested that both residence time and the input of allochthonous carbon sources might substantially influence the quantity of DOC as well as its quality in dam reservoirs.

• Korean Journal of Ichthyology
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• v.24 no.4
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• pp.278-286
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• 2012

This study was examined for information of management of bluegill, Lepomis macrochirus which is disturbance species of underwater ecosystem in Korea. Research of bluegill population was investigated spring-summer and autumn periods in the Han river system from 2009 to 2012. Bluegill inhabited mostly lakes, and restrictedly lived at still area in downstream. The range of relative abundance were 0.2~18.2% in individual number and 0.2~40.0% in biomass and it was subdominant or superiority species for the most part of the lakes. Population structure were analyzed r-strategy in Lake Soyang and Paldang and K-strategy in Lake Uiam and Cheongpyeong. But Lake Chungju was estimated transition period from K-strategy to r-strategy. Condition factor and body weight-total length relations were presented favorable condition. For the nesting, bluegill was formatted the group. And the water depth and the distance from shore were mean 56.3 cm and 191.9 cm respectively in nesting ground. Diameter and depth of nests were mean 42.4 cm and 9.7 cm respectively. These results are available for research of population dynamics and reproductive ecology of bluegill.

• Journal of Microbiology and Biotechnology
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• v.30 no.10
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• pp.1516-1524
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• 2020

Climate change is expected to affect not only availability and quality of water, the valuable resource of human life on Earth, but also ultimately public health issue. A six-year monitoring (total 20 times) of Escherichia coli O157, Salmonella enterica, Legionella pneumophila, Shigella sonnei, Campylobacter jejuni, and Vibrio cholerae was conducted at five raw water sampling sites including two lakes, Hyundo region (Geum River) and two locations near Water Intake Plants of Han River (Guui region) and Nakdong River (Moolgeum region). A total 100 samples of 40 L water were tested. Most of the targeted bacteria were found in 77% of the samples and at least one of the target bacteria was detected (65%). Among all the detected bacteria, E. coli O157 were the most prevalent with a detection frequency of 22%, while S. sonnei was the least prevalent with a detection frequency of 2%. Nearly all the bacteria (except for S. sonnei) were present in samples from Lake Soyang, Lake Juam, and the Moolgeum region in Nakdong River, while C. jejuni was detected in those from the Guui region in Han River. During the six-year sampling period, individual targeted noxious bacteria in water samples exhibited seasonal patterns in their occurrence that were different from the indicator bacteria levels in the water samples. The fact that they were detected in the five Korea's representative water environments make it necessary to establish the chemical and biological analysis for noxious bacteria and sophisticated management systems in response to climate change.