• 한국물환경학회지
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• 제27권4호
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• pp.413-424
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• 2011

The study was aimed to evaluate the applicability of a three-dimensional (3D) hydrodynamic and water quality model, ELCOM-CAEDYM for Yongdam Reservoir, Korea. The model was applied for the simulations of hydrodynamics, thermal stratification processes, stream density flow propagation, and water quality parameters including dissolved oxygen, nutrients, organic materials, and algal biomass (chl-a) for the period of June to December, 2006. The field data observed at four monitoring stations (ST1~ST4) within the reservoir were used to validate the models performance. The model showed reasonable performance nevertheless low frequency boundary forcing data were provided, and well replicated the physical, chemical, and biological processes of the system. Simulated spatial and temporal variations of water temperature, nutrients, and chl-a concentrations were moderately consistent with the field observations. In particular, the model rationally reproduced the succession of different algal species; i.e., diatom dominant during spring and early summer, after then cyanobacteria dominant under warm and stratified conditions. ELCOM-CAEDYM is recommendable as a suitable coupled 3D hydrodynamic and water quality model that can be effectively used for the advanced water quality management of large stratified reservoirs in Korea.

• 한국물환경학회지
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• 제27권4호
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• pp.445-460
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• 2011

The objective of this study was to construct and assess the applicability of the EFDC model for Saemangeum Reservoir as a 3D hydrodynamic and water quality modeling tool that is necessary for the effective management of water quality and establishment of conservation measures. The model grids for both reservoir system only and reservoir-ocean system were created using the most recent survey data to compare the effects of different downstream boundary conditions. The model was applied for the simulations of temperature, salinity, water quality variables including chemical oxygen demand (COD), chlorophyll-a (Chl-a), phosphorus and nitrogen species and algal biomass, and validated using the field data obtained in 2008. Although the model reasonably represented the temporal and spatial variations of the state variables in the reservoir with limited boundary forcing data, the salinity level was underestimated in the middle and upstream of the reservoir when the flow data were used at downstream boundaries; Sinsi and Garyuk Gates. In turn, the error caused to increase the bias of water quality simulations, and inaccurate simulation of density flow regime of river inflow during flood events. It is likely because of the loss of momentum of sea water intrusion at downstream boundaries. In contrast to flow boundary conditions, the mixing between sea water and freshwater was well reproduced when open water boundary condition was applied. Thus, it is required to improve the downstream boundary conditions that can accommodate the real operations of the sluice gates.

• 한국수자원학회논문집
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• 제45권3호
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• pp.331-347
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• 2012

남강댐 하류는 부산 경남의 수자원 장기 계획에 중요한 지역이므로 지속가능한 지표수 관리 및 오염원 제어를 위해 흐름 및 수질 해석이 필요하다. 따라서 본 연구에서는 2차원 수질모형인 RAM4와 3차원 수질모형인 WASP을 각각 수리모형인 RAM2 및 EFDC모형과 연계하여 2 3차원 준연계 모형을 이용한 남강댐 하류에서의 수리 및 수질을 해석하였다. 2차원 흐름해석 모형인 RAM2 적용 결과 만곡부 5개 횡단 측선에서의 유속의 증감경향이 ADCP 실측값과 잘 일치하였으며, 3차원 모형인 EFDC와 유속 분포 및 보 월류 유속이 유사하였다. 또한 정상상태 도달 후의 RAM2-RAM4 연계모의에 의한 BOD 농도와 EFDC-WASP 연계모의에 의한 BOD 농도장이 모의영역 전반에 걸쳐 유사하게 나타났다. 남강댐 하류부의 경우 수리 및 수질이 남강댐 방류량에 크게 좌우되며 남강댐의 수량은 하류부의 수질 및 연안 어업환경에 큰 영향을 미치므로 향후 이에 대한 정량적 분석 시 계산의 효율성 및 모형의 적용성 측면에서 2차원 준연계 모형을 적용하는 것이 바람직한 것으로 판단된다.

• 상하수도학회지
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• 제23권1호
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• pp.15-22
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• 2009

This study reports the serial use of a 3-D hydrodynamic model, EFDC-Hydro and a dynamic water quality model WASP7.2 that are maintained by USEPA. The 48 km section of the Geum River downstream between Daechung Dam and Gongju was selected as a sample study site. Topographical information was used to accurately represent morphology of the study site and boundary conditions were derived from governmental databases including WAMIS by Ministry of Land and Ocean and WEIS by Ministry of Environment. EFDC-Hydro was successfully calibrated for observed water level and WASP was calibrated using monthly observed water quality data obtained from the above sources. It was found that the current water quality target of BOD for the Geum River-H point could not be met on monthly basis though every other tributary of the area would meet its own water quality target as assigned in Korean TMDL. This study proposed the new target BOD water quality for the Gabcheon and Mihocheon as 4.3 and 3.6 mg/l, respectively so that the Geum River-H point can meet the target. When Sejong City is constructed, it is estimated that effluent discharge limit of BOD must be less than 4.5 mg/l to meet water quality of the point. This study shows that it is possible to carry out more precise modeling considering both water movement and water kinetics by using EFDC and WASP simultaneously.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.1184-1188
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• 2005

The impacts of turbidity flow induced by summer rainfall events on water supply, aquatic ecosystems, and socioeconomics are significant and major concerns in most of reservoirs operations. As a decision support tool, the real-time turbidity flow monitoring and modeling system RTMMS is under development using a laterally integrated two-dimensional (2D) hydrodynamic and water quality model. The objectives of this paper is to present the preliminary field observation results on the characteristics of rainfall-induced turbidity flows and their density flow regimes, and the model performance in replicating the fate and transport of turbidity plume in a reservoir. The rainfall-induced turbidity flows caused significant drop of river water temperature by 5 to $10^{\circ}C$ and resulted in density differences of 1.2 to $2.6kg/m^3$ between inflow water and ambient reservoir water, which consequently led development of density flows such as plunge flow and interflow in the reservoir. The 2D model was set up for the reservoir. and applied to simulate the temperature stratification, density flow regimes, and temporal and spatial turbidity distributions during flood season of 2004 After intensive refinements on grid resolutions , the model showed efficient and satisfactory performance in simulating the observed reservoir thermal stratification and turbidity profiles that all are essentially required to enhance the performance of RTMMS.

• 한국환경과학회지
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• 제16권4호
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• pp.505-521
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• 2007

This study estimated response of water duality and pollutant behavior according to the discharge and reuse of treated wastewater by three-dimensional eco-hydrodynamic model, and suggest plan that water quality management and environmental restoration in the coastal area including urban stream of Yeosu, Korea. Dispersions of low-saline water and COD by treated wastewater loads (design facility capacity, about $110,000m^3/d$) were very limited in near of effluent site. Nutrients, however, increase compared to the other water quality factors, especially total nitrogen was very sensitive to input loads. When reuse some of treated wastewater to Yeondeung stream, nitrogen was big influence on estuarine water quality. Although current characteristics of treated wastewater such as discharge and water quality were negligible to the change of marine environment, effluent concentration of COD, TN and TP, especially 40% of TN, are reduced within the allowable pollutant loads for satisfy environmental capacity and recommended water duality criteria. Also, controls of input point/non-point sources to Yeondeung stream and base concentration of pollutants in coastal sea itself are very necessary.

• 한국농공학회논문집
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• 제58권6호
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• pp.9-21
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• 2016

Agricultural reservoirs in Korea have been recognized as an emerging resource for recreational and cultural activities for residents. However, most of the reservoirs are eutrophic and showing high level of contamination with nuisance algal bloom and offensive odor during the summer. For better management and restoration of the reservoirs' water quality, scientific modeling approaches could be used to diagnose the problems and evaluate the efficacy of alternative control measures. The objectives of this study were to validate the performance of a three-dimensional (3D) hydrodynamic and water quality model (Environmental Fluid Dynamics Code, EFDC) for a eutrophic agricultural reservoir and assess the effect of bypassing of the effluent from a wastewater treatment plant on the reservoir water quality. The 3D model successfully simulated the temporal variations of water temperature, DO, TOC, nitrogen and phosphorus species and Chl-a observed in 2014 and also captured their spatial heterogeneity in the reservoir. The simulation results indicated that the point source bypassing may reduce the T-N and T-P concentrations of the reservoir by 6.6 ~ 8.2 %, and 1.7 ~ 16.8 %, respectively. The bypassing, however, showed a marginal effect on the control of TOC due to the increased algal biomass associated with the increased water retention time after bypassing as well as the lower TOC level of the effluent compared to the ambient reservoir water.

• 환경영향평가
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• 제32권6호
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• pp.473-487
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• 2023

1970~1980년대 준공된 우리나라의 다목적댐 저수지에는 발전방류를 위한 고정식 취수구가 심층에 설치되어 있어 일부 댐 하류에서는 냉수 방류에 의한 농작물 냉해, 안개 일수 증가 등의 문제점이 제기된 바 있다. 본 연구에서는 고정식 취수구를 통해 심층 취수가 이루어지고 있는 합천호를 대상으로 취수 수심이 저수지의 수온 성층 구조와 방류 수온에 미치는 영향을 분석하였다. 3차원 수리수질모형인 AEM3D를 이용하여 합천호의 연직 수온 분포를 재현하고 계절별 수온성층 구조를 분석하였으며, 수문 조건에 따른 수온성층 변화를 비교 분석하기 위하여 풍수해와 갈수해를 대상으로 모델링 하였다. 또한 취수심 변경 시나리오를 적용함으로써 취수 수심이 수온성층 구조에 미치는 영향을 분석하였다. 모의 결과 심층 취수를 표층 취수로 변경할 경우 수온약층의 형성 위치가 풍수해 6.5 m, 갈수해 6.8 m 감소하여 더 얕은 수심에 형성될 것으로 분석되었다. 또한 수체 안정도 지수인 Schmidt Stability Index (SSI)와 Buoyancy frequency (N²)가 증가하여 수온성층 강도가 증가하는 것으로 나타났다. 표층 취수시 연평균 방류수온이 풍수해 3.5℃, 갈수해 5.0℃ 증가하여 하류하천의 영향은 감소하나, 호내의 저수온층 수체적과 수온성층 강도가 증가하므로 추후 수질관리를 위해 취수심을 댐 운영의 주요인자로 고려해야 할 것으로 판단된다.

• 한국물환경학회지
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• 제31권4호
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• pp.367-376
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• 2015

The momentum and kinetic turbulent energy carried by the wind to a stratified lake lead to basin-scale motions, which provide a major driving force for vertical and horizontal mixing. A three-dimensional (3D) hydrodynamic model was applied to Lake Tahoe, located between California and Nevada, USA, to simulate the dominant basin-scale internal waves in the deep lake. The results demonstrated that the model well represents the temporal and vertical variations of water temperature that allows the internal waves to be energized correctly at the basin scale. Both the model and thermistor chain (TC) data identified the presence of Kelvin modes and Poincare mode internal waves. The lake was weakly stratified during the study period, and produced large amplitude (up to 60 m) of internal oscillations after several wind events and partial upwelling near the southwestern lake. The partial upwelling and followed coastal jets could be an important feature of basin-scale internal waves because they can cause re-suspension and horizontal transport of fine particles from nearshore to offshore. The internal wave dynamics can be also associated with the distributions of water quality variables such as dissolved oxygen and nutrients in the lake. Thus, the basin-scale internal waves and horizontal circulation processes need to be accurately modeled for the correct simulation of the dissolved and particulate contaminants, and biogeochemical processes in the lake.

• 한국수자원학회논문집
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• 제41권12호
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• pp.1187-1198
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• 2008

국내 많은 저수지들과 그 하류하천은 높은 탁도를 가진 물의 장기적인 방류로 인해 수자원 이용과 수생태계 관리에 많은 어려움을 겪고 있다. 탁도($C_T$)는 물의 탁한 정도를 나타내는 척도로써, 수질과 수환경의 건강을 평가하는 매우 중요한 지표로써 광범위하게 사용되어 왔지만, 모형의 검증에 필요한 실험 자료의 부족으로 인해 탁도 모델링에 대한 연구는 지금까지 매우 부족하였다. 본 연구의 목적은 광범위한 현장 실측자료를 이용하여 성층화된 대청호로 유입한 탁수의 밀도류 거동 모의를 위한 3차원 수리-입자동력학 연동 수치모형인 ELCOM-CAEDYM의 적용성을 검증하는데 있다. 입자크기에 따라 구분된 3개 그룹의 부유물질 (SS) 농도가 모형의 모의변수로 사용되었으며, 모형 변수인 SS와 저수지내 실측값의 $C_T$의 변환을 위해 저수지 지점별로 측정한 SS-$C_T$ 상관관계를 사용하였다. 모의결과는 2004년에 대청호의 회남과 댐앞 지점에서 수심별로 실측한 수온과 탁도 자료와 비교함으로써 검증하였다. 모형은 저수지의 성층구조, 탁수를 포함한 하천 밀도류의 시간에 따른 진행과정을 잘 재현하였으며, 탁도의 수직분포와 크기도 실측값과 부합하였다. 본 연구에서 제시한 3차원 수치모형과 탁도 모델링 방법론은 유사한 탁도 문제를 가지고 있는 다른 저수지에서도 탁수의 최적관리를 위한 지원 도구로써 사용 가능하다고 사료된다.