• 한국지반공학회논문집
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• 제26권4호
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• pp.47-58
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• 2010

불포화 흐름을 고려하지 않는 도해법 (Casagrande, 1961; Cedergren, 1997)과 근사식(Sakamoto, 1998)에 의한 중심코어형 사력댐 코어죤의 침투량은 실제 침투거동과는 차이가 있고, 저수위 변화에 대한 침투량 변화경향의 파악도 곤란하다. 본 연구에서는 소양강댐에 대한 2차원 정상상태 및 비정상상태 침투류해석으로 저수위, 포화투수계수, 불포화수리특성 변화에 대한 정상상태 침투량과 정상상태 도달시간에 미치는 영향요인을 분석하였다. 분석결과 침투량은 정규화된 선형 관계식으로 예측이 가능하고, 불포화 예측변수 n이 정상상태 침투량과 정상상태 도달시간에 가장 큰 영향을 주었다. 본 연구에서 제시한 예측기법은 복잡한 3차원 해석 및 여러 단면에 대한 2차원 해석을 수행하지 않고도 댐 설계자 및 안전관리 실무자가 중심코어형 사력댐의 침투량을 산정하여 실측치와의 정량적 분석에 손쉽게 이용할 수 있을 것으로 생각된다.

• 대한환경공학회지
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• 제30권10호
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• pp.975-983
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• 2008

다공매질을 이용한 여과에서 오염물은 바깥 부위에서 활발히 제거된다는 점을 고려하여, 새로운 여과장치인 폴리에스터 재질의 원통형 다공매질을 고안하여 이 장치가 호소수에서 오염을 제거할 수 있는지 경산시의 삼천지에서 실험하였다. 원수에 포함된 유기오염물은 여재에 포획된 후 시간을 두고 미생물에 의해 분해되는 것을 알 수 있었고, 오염물질 제거효율은 탁월하여 COD$_{Cr}$ 19$\sim$27%, COD$_{Mn}$ 37$\sim$43%, BOD$_5$ 67$\sim$81%, SS 99% 이상, 탁도 93% 등이었다. 본 연구로부터 이 장치가 호소의 수질개선책의 일환으로 활용될 수 있을 것으로 기대되었다.

• 한국물환경학회지
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• 제27권1호
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• pp.73-87
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• 2011

An abnormal mono-specific bloom of the cyanobacterium Microcystis aeruginosa had developed at a specific location (transitional zone, monitoring station of Hoenam) in Daecheong Reservoir from middle of July to early August, 2001. The maximum cell counts during the peak bloom reached 1,477,500 cells/mL, which was more than 6~10 times greater than those at other monitoring sites. The hypothesis of this study is that the timing and location of the algal bloom was highly correlated with the local environmental niche that was controled by physical processes such as hydrodynamic mixing and pollutant transport in the reservoir. A three-dimensional, coupled hydrodynamic and ecological model, ELCOM-CAEDYM, was applied to the period of development and subsequent decline of the bloom. The model was calibrated against observed water temperature profiles and water quality variables for different locations, and applied to reproduce the algal bloom event and justify the limiting factor that controled the Microcystis bloom at R3. The simulation results supported the hypothesis that the phosphorus loading induced from a contaminated tributary during several runoff events are closely related to the rapid growth of Microcystis during the period of bloom. Also the physical environments of the reservoir such as a strong thermal stratification and weak wind velocity conditions provided competitive advantage to Microcystis given its light adaptation capability. The results show how the ELCOM-CAEDYM captures the complex interactions between the hydrodynamic and biogeochemical processes, and the local environmental niche that is preferable for cyanobacterial species growth.

• 생태와환경
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• 제40권4호
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• pp.581-585
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• 2007

Swarm formation of Scapholeberis kingi Sars 1903 was observed in a shallow reservoir on 27 May 2007 (Dongpan Reservoir) for the first time. Dense swarms composed of asexual females, only occurred during daytime (13:00-17:00, local time) at the littoral zone. Correlation between density of S. kingi and environmental factors such as water temperature and density of juvenile fish were positively significant. Therefore, it is suggested that the swarming of S. kingi seems to be induced for predator avoidance than increase of mating chance, and water temperature may affect their swarming behavior.

• 한국농공학회지
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• 제37권3_4호
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• pp.48-60
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• 1995

A flood - flow forecasting system model of river basins has been developed in this study. The system model consists of the data management system(the observation and telemetering system, the rainfall forecasting and data-bank system), the flood runoff simulation system, the reservoir operation simulation system, the flood forecasting simulation system, the flood warning system and the user's menu system. The Multivariate Rainfall Forecasting model, Meteorological factor regression model and Zone expected rainfall model for rainfall forecasting and the Streamflow synthesis and reservoir regulation(SSARR) model for flood runoff simulation have been adopted for the development of a new system model for flood - flow forecasting. These models are calibrated to determine the optimal parameters on the basis of observed rainfall, 7 streamfiow and other hydrological data during the past flood periods.

• 한국농공학회논문집
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• 제56권1호
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• pp.71-79
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• 2014

In this study, an experiment with large-scale model was performed according to raising the embankment in order to investigate the behavior of failure for embankment and spillway transitional zone due to overtopping. The pore water pressure, earth pressure, settlement and failure pattern by a rapid drawdown and overtopping were compared and analyzed. The pore water pressure and earth pressure at spillway transitional zone by overtopping increased a rapidly with the expansion of seepage erosion, but the crest showed a smally change due to effect of the inclined core type. And it is considered an useful data that can accurately estimate the possibility of failure of the reservoirs. A settlement at overtopping decreased a rapidly due to failure of crest. The relative settlement difference due to change of the water level at the upstream and downstream slope cause increase largely crack of crest. The behavior of failure by overtopping was gradually enlarged towards reservoirs crest from the bottom of the spillway transition zone, the inclined core after the raising the embankment was influenced significantly to prevent the seepage erosion.

• Journal of Ecology and Environment
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• 제38권3호
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• pp.383-388
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• 2015

Reservoirs consist of two different environments, the littoral and the pelagic zone, and different fishing gear is commonly used in each zone-gill nets in the pelagic zone and electrofishing in the littoral zone. However, an active fishing gear, the cast net, is normally used instead of electrofishing for scientific studies in South Korea. In order to estimate cast net effectiveness for determining fish status in reservoirs, the study was conducted at 15 reservoirs with two different fishing gears: a cast net in the littoral zone and gill nets in the pelagic zone. When combining catches of both gears, species richness increased substantially compared to using one gear only. There was a size difference in fish caught by each net, and small fish were predominantly caught with the cast net due to its small mesh size (7 mm). The combined length of six species, used for length-weight relationship analysis, collected with the cast net was smaller than that collected with gill nets (independent t-test, P < 0.05). In this study, cast net sampling provided sufficient data for the littoral zone, but not enough to identify the overall fish assemblage in studied reservoirs. Utilization of only one gear can therefore lead to substantial underestimation of fish status, and a combination of both gears is recommended for determining more reliable estimates of fish status in reservoirs.

• Spatial Information Research
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• 제18권3호
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• pp.1-11
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• 2010

최근 댐 저수지 주변의 3차원 공간정보 구축은 퇴사량 조사와 같은 댐 관리 업무에 매우 중요한 부분이나 기존에는 지형측량을 위해 토탈스테이션과 단빔음향측심기(SBES)를 사용한 관계로 정밀한 지형자료 취득이 어려웠다. 본 연구에서는 LiDAR와 멀티빔음향측심기(MBES)를 이용하여 댐 저수지 주변의 정밀 지형자료를 구축하는 기법을 제시하였다. 먼저, 육상부에 대해 LiDAR 측량을 수행한 후 지상기준점을 이용한 캘리브레이션을 수행하였으며 건물이나 수목을 제거하는 알고리즘을 통해 육상부의 DEM 자료를 구축하였다. 구축된 LiDAR DEM을 GPS 지형측량과 검측한 결과 표준오차는 0.108m로 나타났으며, 따라서 LiDAR 허용오차를 만족하는 3차원 지형자료를 구축할 수 있었다. 또한 저수지에 대해서는 MBES를 수행한 후 지형측량과의 검측과정을 통해 IHO의 수심측량 허용오차 기준을 만족하는 지형정보를 구축할 수 있었다. 그리고 LiDAR와 MBES 측량자료를 통합한 후 고해상도 정사영상지도와의 연계를 통해 퇴사량 예측 및 지형변화 모니터링 등과 같은 댐 관리 업무에 활용 가능한 3차원 공간영상정보를 구축할 수 있었다.

• 생태와환경
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• 제42권2호
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• pp.212-220
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• 2009

본 연구는 2008년 11월에 마산저수지를 대상으로 어류 종조성 및 섭식길드 및 오염내성길드에 따른 생태지표 특성을 분석하고, 이와 연관된 화학적 수질 특성 변화를 분석하였다. 채집된 어류는 총 12종(6과)으로 나타났고, 주요 우점종은 피라미, 치리, 참붕어 등으로 나타났다. 한국 고유종은 3종만이 출현하였으며, 외래도입종은 떡붕어 1종이 출현하였다. 생태지표 특성 분석에 따르면, 내성종 및 잡식종의 상대풍부도는 각각 98%로 단연 우점하는 것으로 나타나, 이화학적 질적저하 및 물리적 서식지 교란요인에 의한 영향을 반영하고 있었다. 호안에 따른 종분포 특성 분석 결과, 정수식물이 발달한 호안에서 대부분의 어류가 95% 이상이 채집된 것으로 나타났다. 또한 하상 기질 특성에 따른 분석 결과, 뻘(Silt)로 된 구간에서 가장 많은 종 (11종, 91.7%)이 채집되어, 하상기질에 따라 유의한 차이를 보이고 있었다. 화학적 수질자료 분석에 따르면, 호수 영양상태 지표인 총인(TP) 및 Chl-a의 농도는 모두 과영양상태인 것으로 나타났으며, 호수의 유기물오염의 지표로 사용되는 COD도 평균 10.9 mg $L^{-1}$로 나타났다. 마산저수지의 이러한 수질저하는 어류의 섭식구조(잡식종의 증가) 및 내성종의 증가 등을 통해 반영되었다. 향후 마산저수지의 어류상 및 어류 종조성이 향상을 위해서 수질 개선 및 서식지 복원이 펼요할 것으로 사료된다.

• 한국물환경학회지
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• 제18권3호
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• pp.261-270
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• 2002

The artificial aeration in the middle and the small scale reservoirs is widely used to destroy the stratified layer and algal boom. This study has been conducted at the Youncho reservoir located in Keoje island since Jan. 2000 to suggest the most suitable control strategy of the artificial aeration and reduce the side effect. The main results obtained from this research are as follows. The starting time of aeration for destratification was adjusted from the end of March to the beginning of April when the natural stratification is started. In order to prevent an anoxic condition the artificial mixing should be started by the middle of April when the DO in hypolimnion is dropped to less than $5mg/{\ell}$. The decrease DO, caused by the increase in water temperature, spreads rapidly from hypolimnion to themocline. Thermal stratification disappeared after the onset of artificial aeration within 7 days in the Yuncho reservoir. The air diffusers decrease water temperature in the layer of epilimnion and thermocline, but rise it in hypolimnion. The continuous operation of air diffuser prevent the stratification and anoxic condition in hypolimnion despite of the rising of water temperature and algal abundance. The algal abundance is not observed in effective zone by aeration. The turbidity rising problem induced from the aeration is avoided by keeping an air diffuser about 1.5m high from the bottom of lake. During the summer season, ceasing the aeration should be decided carefully. And also, it is necessary to operate the system it considering weather and temperature, and depending on the number and the position of aerators.