• Journal of Korea Water Resources Association
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• v.42 no.1
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• pp.61-73
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• 2009

To efficiently carry out the flood management of a multipurpose dam, two flood forecasting models are developed, each of which has the capabilities of forecasting upstream inflows and flood discharges downstream of a dam, respectively. The models are calibrated, validated, and evaluated by comparison of the observed and the runoff forecasts upstream and downstream of Namgang Dam. The upstream inflow forecasting model is based on the Grey system theory and employs the sixth order differential equation. By comparing the inflows forecasted by the models calibrated using different data sets with the observed in validation, the most appropriate model is determined. To forecast flood discharges downstream of a dam, a Grey model is integrated with a modified Muskingum flow routing model. A comparison of the observed and the forecasted values in validation reveals that the model can provide good forecasts for the dam's flood management. The applications of the two models to forecasting floods in real situations show that they provide reasonable results. In addition, it is revealed that to enhance the prediction accuracy, the models are necessary to be calibrated and applied considering runoff stages; the rising, peak, and falling stages.

• 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.

• Journal of Korea Water Resources Association
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• v.42 no.1
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• pp.1-8
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• 2009

In this study, based on the major activities which might have affected the ecological system of the Geum River, a conceptual model was proposed to guide scenario development for the eco-hydrological river evaluation. Also, an analysis method employing a set of models consisting, with other supporting programs, of KModSim for watershed network analysis and RAP for ecosystem analysis was developed for eco-hydrological river assessment. Then, hydrological analyses with various scenarios were conducted to examine the flow regime changes expected from the construction and operation of the Youngdam Multipurpose Dam (YMD) and Daecheong Multipurpose Dam (DMD) in the Geum River basin. The results indicated that the "Percentile 10" values for 10% exceeding time were decreased by 20.5% and 8.0% at Sutong downstream of YMD and Gongju downstream of DMD, respectively, while "Percentile 90" values for 90% exceeding time were increased by 56.3% and 340.8% at Sutong and Gongju, respectively, resulting in the reduction of the high flow variability typical for unregulated rivers in Korea. The results of eco-hydrological analyses will be presented in the following papers.

• Journal of Environmental Science International
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• v.25 no.9
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• pp.1253-1267
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• 2016

After large-scale flooding damage occurred along the Imjin river in 1996, 1998, and 1999, the Hantan river flood control dam was planned, and it has since been under construction. Unlike existing dams in Korea, the Hantan river flood control dam will remain fully open except during high floods, when the dam will store flood water temporarily to reduce flood peaks and flood water volume downstream. During past flooding seasons, floating debris has caused difficulties in the management of large-scale dams. Most of the existing multipurpose dams in Korea have installed nets to collect floating debris based on many years of experience with and data about inflow and distribution of floating debris in the dams. For the Hantan river flood control dam, however, collection of data about inflow and distribution of floating debris is not possible as the dam is located near the border area between North and South Korea. In order to devise a preliminary plan to collect floating debris in the Hantan river flood control dam, an EFDC hydrodynamic model was used to analyze the behavior of floating debris during high floods. The Lagrangian particle tracking method was utilized to simulate the behavior of floating debris in the dam. Based on the analysis of paths and final destinations of the particles, seven collection points were selected where it seemed to be effective to collect floating debris, as debris is likely to accumulate there in high density.

• Water for future
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• v.28 no.3
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• pp.187-195
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• 1995

This study aims at suggesting an alternative to improve current capacity of flood control for the existing Soyanggang multi-purpose dam which was constructed 20 years ago as a largest dam in Korea. The newly estimated value of the probable maximum precipitation(PMP) is 760.0 mm which is based on the hydrometeorological method. The peak inflow of 1000 years return period at the time of construction was 13,500$m^3$/s. However, the newly estimated peak inflow of the PMF is 18,100$m^3$/s which is 1.34 times bigger than the original one. In order to adopt the newly estimated PMF as a design flood, following four alternatives were compared; (1) allocation of more flood control space by lowering the normal high water level, (2) construction of a new spillway in addition to the existing one, (3) raising the existing dam crest, (4) construction of a new dam which has relevant flood control storage at the upstream of the Soyanggang multipurpose dam. The preliminary evaluation of these alternatives resulted in that the second alternative is most economical and feasible. So as to stably cope with the newly estimated PMF by meeting all the current functions of the multi-purpose dam, a detailed study of an additional spillway tunnel has to be followed.

• Journal of Korean Society of Rural Planning
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• v.18 no.3
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• pp.175-186
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• 2012

This is a study of a residential area for displaced villagers planned for residents of Gyodo Village who must evacuate their hometown because of flooding due to the Hantan River Dam Project. The study aims to construct a plan for a new residential area for the villagers focusing on reflecting the existing characteristics of their former village and on ensuring sustainability for the new village. Departing from previous practice of focusing on merely physical aspects when planning, the current study is significant in that it presents a new planning process and method for a sustainability-focused plan. While the study has many limitations such as objectivity in the process of deriving the sustainability indicators and the appropriateness of the indicator questions, it is hoped that future studies on sustainability will serve to make up for these limitations and problems.

• Journal of Korea Water Resources Association
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• v.42 no.5
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• pp.407-414
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• 2009

A quantitative analysis was conducted to study the impacts of artificial flow alteration on fish habitate condition change in the Geum River downstream the Daechung Multi-purpose Dam (DMD). River Analysis Package (RAP) was employed for the analysis and three fish species of black shiner, long nose barbel and Korean shinner were selected as icon species. The results of the analysis showed enhaced fish habitat conditions during low flow seasons in spring and fall after DMD construction, while the impact of the Youngdam Multipurpose Dam located upstream the DMD was insignificant. This result could be attributed to the fact that the increased flow during dry seasons helped create preferable habitat conditions for the fish species tested in this study.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.705-711
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• 2008

In case of the domestic condition, as the initiating from Sumjin River Dam, total 14 units of multipurpose dams had been constructed in 1965 for the roles of flood control, waterpower generation, irrigation, water supply, industrial water supply. In the case of such multipurpose dam, it produces electric energy by converting the potential energy utilizing its head and quantity of the water into kinetic energy. However, in this process, since during the time when the turbine connected to the hydraulic turbine dynamo revolves and there occurs a loud noise, it brings the physical, mental bad influences to those people also a decline of an effective working efficiency. On such point of view, after selection of various 16 measurement points, this study has measured and analyzed the travelling characteristics of noise generated at the hydraulic turbine dynamo in Daechung Dam, and also has evaluated the degree of indoor noise using the evaluation index such as PSIL, NC. As the result of noise-evaluation, in case of Daechung Dam, since the noise damage grade appears very seriously at various spaces, it is considering that its soundproof measure would be necessitated keenly. Also, it is considered that such data could be utilized as the valuable material hereafter for establishment of an efficient noise-reduction countermeasure and a comfortable working environment for the hydraulic turbine dynamo plant.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.755-758
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• 2007

For a stable water supply, it is necessary to consider the present unusual change in the weather, seasonal variation of water use, and the frequency and duration of low flow. Therefore, in this study, a theoretical background of specific probability distribution type and the reliability of frequency analysis for the time series of low flow data was investigated and programmed to support the operation of multipurpose dam.

• 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.