• Journal of Environmental Impact Assessment
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• v.20 no.1
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• pp.89-96
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• 2011

This study was carried out to assess the variations of water quality caused by the dam construction on the river. Six dams-Yongdam, Miryang, Hoengseong, Boryeong, Jangheung and Buan- constructed recently in Korea were selected for the study. Chemical oxygen demand(COD) was increased in the initial stage of water storage at dams compared to the lotic(river) environment, but after 3 years it was maintained lower and stabilized concentrations. Five dams except for Jangheung Dam were maintained Ia~Ib grade conditions under the water quality criteria of Korea. The concentrations of total nitrogen(T-N) were decreased under the lentic(reservoir) environment compared to the river status. Total phosphorus(T-P) was decreased 13~63% at the reservoir condition. We concluded that increase of COD concentration was due to the debris organic materials of the land, but temporary phenomenon. T-N and T-P concentrations were decreased at the lentic condition compared to the lotic.

• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.37-42
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• 2014

In Korea while the dam or reservoir is an important water resource, the value of this water resource is deteriorating by thermal-induced stratification. To ameliorate the water quality of reservoir by breaking stratification the use of air diffuser system is now widespread in Korea. According to the previous research, dynamics of bubble plume and destratification efficiency depended upon two dimensionless groupings; Mh and Pn suggested by Asaeda et al (1993). However, these two variables only include Q, N, H, g, u. and installed Boryeong reservior in appropriate width of water aeration, air dose and number of installations after calculating by applying these figures. This paper is performed to find out effect analysis about water aeration improvement to break thermal stratification.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.52-52
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• 2017

우리나라에서 2014년부터 2016년까지 중부지방을 중심으로 지속된 강우부족은 용수공급에 피해를 발생시키는 주요 원인이 되었다. 2014년부터 2016년까지 보령 기상관측소의 연강수량은 각각 1,010.6 m, 782.5 mm, 792.8 mm였으며 이는 보령 기상관측소 연강수량의 평년값인 1,244.3 mm의 81.2 %, 62.9 %, 63.7 %에 해당하는 양이었다. 이러한 강우부족으로 인하여 충청남도 서북부권에 용수공급을 담당하고 있는 보령댐의 저수율이 20 % 미만으로 감소하는 문제가 발생하였다(2015년 11월 6일 기준). 국토교통부는 보령댐의 저수율 감소가 지속될 경우 보령댐 용수공급 지역에 피해가 발생할 것으로 판단하였고 이러한 피해를 저감시키는 방안으로 금강 백제보 하류의 물을 보령댐 상류로 공급하기 위한 긴급용수공급 시설인 보령댐 도수로를 설치하였다. 보령댐 도수로 운영 시 지형 및 수질 문제를 해결하기 위하여 가압시설, 정수시설과 같은 부대시설이 함께 설치되었다. 이로 인해 도수로 운영 시 부대시설의 운영비용이 소요되므로 보령댐 도수로는 운영일수를 최소화하고 보령댐의 용수공급은 최대화하는 도수로의 운영방안이 필요하다. 본 연구에서는 보령댐 도수로의 효율적인 운영방안을 모색하기 위하여 다양한 보령댐 도수로 운영방안을 설정하고 각 운영방안 따른 저수지 모의운영을 실시하여 보령댐 도수로의 운영효과를 분석하고자 하였다. 도수로의 운영방안은 보령댐 유역의 유역평균강수량을 활용하여 산정한 SPI, 보령댐 실측유입량을 활용하여 산정한 월 평균유입량, 용수공급 조정기준의 단계별 저수량 등을 활용하여 설정하였다. 또한 저수지 모의운영 결과를 평가하기 위한 지표로 용도별 용수공급 신뢰도와 용수공급 조정기준의 각 단계별 도달일수, 도수로 운영일수, 무효방류량 등을 산정하고 그 결과를 비교 분석하였다.

• Environmental and Resource Economics Review
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• v.21 no.4
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• pp.921-945
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• 2012

Conditional Logit (CL) model is widely used since its model estimation and interpretation of results of the model is relatively easy, on the other hand, it has the limit of preference heterogeneity of respondents being not fully considered. In this study we used the two models, Mixed Logit (ML) Model and Latent Class Model (LCM) to explain preference heterogeneity of respondents for protection for Boryeong Dam wetland. As a result of the examination for heterogeneity in Boryeong city and six metropolitan areas, we found there was significant difference between two regions. While there was explicit preference heterogeneity within respondents in Boryeong city, we found little heterogeneity within respondents in six metropolitan areas. Thus in the case of six metropolitan areas, CL model can be used for parameter estimation while in the case of Boryeong city, WTP estimates are based on parameter estimates from ML model to reflect the heterogeneity within respondents. Additionally, ML model with interaction and 2-class LCM for respondents in Boryeong city were used to explain the sources of the heterogeneity. The ML model with interaction has advantage of explaining individual unobserved heterogeneity. However The comarison between these two models reflects the fact that LCM provided added information that was not conveyed in the ML model with interaction. Thus, Preference heterogeneity within respondents in this study may be better explained by class level through LCM rather than indiviual level through ML model.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.428-428
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• 2017

In this study, three optimization techniques efficiency is assessed for calibration of the GR4J model for streamflow simulation in Selmacheon, Boryeong Dam and Kyeongancheon watersheds located in South Korea. The Penman-Monteith equation is applied to estimate the potential evapotranspiration, model calibration, and validation is carried out using the readily available daily hydro-meteorological data. The Shuffled Complex Evolution-University of Arizona(SCE-UA), Uniform Adaptive Monte Carlo (UAMC), and Coupled Latin Hypercube and Rosenbrock (CLHR) optimization techniques has been used to evaluate the robustness, performance and optimized parameters of the three catchments. The result of the three algorithms performances and optimized parameters are within the recommended ranges in the tested watersheds. The SCE-UA and CLHR outputs are found to be similar both in efficiency and model parameters. However, the UAMC algorithms performances differently in the three tested watersheds.

• Geophysics and Geophysical Exploration
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• v.16 no.3
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• pp.109-118
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• 2013

On and near the 23-m high earthen Cheongcheon dam in Boryeong City, Korea, short seismic refraction and surface-wave profiles were conducted using a 5-kg sledgehammer. From vertical and horizontal components of the seismic waves, near-surface P-wave velocities (${\nu}_p$) and S-wave velocities (${\nu}_s$) were derived by inverting first-arrival refraction times and dispersion curves of Rayleigh waves. Average ${\nu}_p$ and ${\nu}_s$ for the Jurassic sedimentary basement were determined to be 1650 and 950 m/s at a depth of 30 m directly beneath the dam and 1650 m/s and 940 m/s at a depth of 10 m at the toe of the dam, respectively. The dynamic Poisson's ratio for these strata were therefore in the range of 0.24 to 0.25, which is consistent with ratios for consolidated sedimentary strata. Near a 45-m borehole 152 m downstream from the dam crest, an SH tomogram indicates a refraction boundary with an average ${\nu}_s$ of 870 m/s at depths of 10 ~ 12 m. At this site, the overburden comprises the upper layer with relatively constant ${\nu}_p$ and ${\nu}_s$ around 500 and 200 m/s, respectively, and the lower layer in which both ${\nu}_p$ and ${\nu}_s$ increase with depth almost linearly. The dynamic Poisson's ratios for the overburden were in the range of 0.30 to 0.43.

• Journal of Korean Society on Water Environment
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• v.28 no.1
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• pp.102-108
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• 2012

This study has performed comparative analysis on characteristics of reservoirs in their use through correlation analysis on seasonal variation of water quality factors in agricultural reservoirs and multipurpose dams. Agricultural reservoirs show the high relationship between Chl-a and other water quality factors while the correlation among COD, BOD, and SS is strong in multipurpose dams. Agricultural reservoirs have the high relationship between various water quality factors in season such as Chl-a and pH ($R^{2}=0.294$) in Spring, pH and water temperature ($R^{2}=0.246$) in Summer, and Chl-a and BOD ($R^{2}=0.435$) in Fall, and between COD and BOD ($R^{2}=0.370$) in Winter, respectively, for Sapgyo reservoir while Chl-a and T-P ($R^{2}=0.739$) in Spring, T-P and SS ($R^{2}=0.876$) in Summer, and Chl-a and SS ($R^{2}=0.600$) in Fall, and between COD and SS ($R^{2}=0.998$) in Winter, respectively, for Seokmun reservoir. Boryeong dam has the strong relationship between T-P and SS ($R^{2}=0.511$) in Spring while the relation between COD and SS is high in other seasons with the values of $R^{2}$ of 0.362, 0.665, and 0.500 in Summer, Fall, and winter, respectively. The first and second water quality factors in relationship are COD and BOD in Sapgyo and Seokmun reservoirs, which is similar to the characteristics in Winter for multipurpose dams. Chl-a has no relationship with other water quality factors in Boryeong dam in operation for both flood control and low water regulation purposes. The result of this research is expected to provide contributions to the seasonal water quality control and analysis on characteristics for each reservoir by monitoring.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.10
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• pp.1532-1539
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• 2017

The floating photovoltaic system is a new concept in the renewable energy technology. That is similar to land based photovoltaic technology except floating system. So the system needs buoyant objects, mooring, ect, besides modules and supports, and that is able to withstand in water level changes and wind strength. Therefore the floating photovoltaic system is much different from land photovoltaic system. K-water (Korea Water Resources Corporation) has been operating two floating photovoltaic system that's capacity is 100 kW and 500 kW respectively since in summer 2011 for commercial generation, and have construction project for 2,000 kW in Boryeong multipurpose Dam and other areas. Furthermore K-water was developing a tracking-type floating photovoltaic system at Daecheong multipurpose Dam and developed and installed an ocean floating photovoltaic demonstration plant at Sihwa Lake in October 2013 for R&D. In this paper, we introduce that structure of floating photovoltaic system include buoyant structure, mooring system and auxiliary device. Especially the rope which is in part of mooring should be always maintain tension under any water level. Also we explain about structure design concept to wind load in an every loading condition and a kind of structure materials and PV structure types used in water environment. Especially ocean floating PV system is affected by tidal current and typhoon. So there are considering the elements in design. Finally we compare with floating and land photovoltaic on power amount. As a result of that we verified the floating photovoltaic system is more about 6.6~14.2 % efficiency than a general land photovoltaic system.

• Journal of Korean Society on Water Environment
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• v.28 no.1
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• pp.78-83
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• 2012

Man-made reservoirs over 95% in Korea are shallower than 10 meters in depth, which is apt to cause eutrophication. This study has characterized long-term trends in water quality factors for the selected six reservoir points in the Kum River watersheds, and then estimated the seasonal trophic state index for each reservoir. The reservoir trophic state was evaluated at four trophic levels using the Korean trophic state index, TSIKO. It is observed from seasonal results for six reservoirs that the highest value of the trophic state index is estimated in summer while the trophic state index value is low in spring and winter seasons. Especially, the Boryeong Lake has a relatively lower trophic state index since this reservoir has been managed properly for water withdrawal and irrigation. It is expected that the seasonal trophic state index resulted from this study can contribute toward long-term water quality improvement plans for reservoirs.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.20-20
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• 2018

다년동안 지속되는 가뭄현상이 빈번하게 발생하고 있지만, 우리나라에서는 지금까지 장기 가뭄보다 단기 가뭄에 초점을 맞춰 연구가 진행되어 왔다. 다년 가뭄을 반영하지 않고 댐의 저수용량을 평가할 경우, 저수용량이 과소평가될 수 있기 때문에 다년간의 가뭄을 반영한 시계열 모형을 통해 다양한 시나리오를 생성하고 분석해야 한다. 본 연구에서는 2015년부터 2017년까지 장기 가뭄이 발생한 보령댐의 1998년-2017년까지의 관측 월평균 유입량 자료를 바탕으로 Autoregressive Moving Average(ARMA)시계열 모형과 Hurst Coefficient를 추가하여 장기지속성을 반영하도록 개발된 시계열 모형인 Autoregressive Fractionally Integreated Moving Average(ARFIMA)를 사용하여 보령댐 500년 기간의 유입량 자료를 생성하였다. Hurst Coefficient는 Hurst가 제안한 Rescaled Range(R/S)방법 외에도 경험식, 이론식을 모두 사용하여 산정하였다. 생성된 자료가 관측 자료의 장기지속성을 잘 반영하는지에 대한 검증을 위해 관측자료의 누적유입량으로부터 선형 이동평균방법을 사용하여 가뭄기준을 산정하고, 생성한 유입량 자료가 장기가뭄을 반영하고 있는지 판단하였다. 그 결과 가뭄의 장기지속성을 잘 반영하는 시계열 모형을 선정하였으며, 향후 연구를 통해 미래 기후변화 시나리오를 반영한 장기가뭄 분석을 수행할 예정이다.