• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.73.2-73.2
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• 2009

• Structural Monitoring and Maintenance
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• v.6 no.1
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• pp.1-17
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• 2019

Preserving reservoir safety has recognized to be important for the public where a vast majority of dams are located upstream of greatly populated cities and industrialized areas. Buckling, floatation and cavitation have caused failure in the spillway gates and conveyance features during past catastrophic events; showed their vulnerability and need for regular inspection along with reviewing design calculations to ensure the spillway meet current design standards. This paper investigates the hydraulic and structural consideration of dam's spillway by evaluating the data of Karkheh Dam's. Discharge capacity, flood routings and cavitation damage risk were main features for hydraulic considerations where hydrostatic and hydrodynamic forces and stability conditions were considered in structural considerations.

• Water for future
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• v.29 no.2
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• pp.209-219
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• 1996

The existing gate operation rule of Paldang hydroelectric plant has been used since the construction of the dam in 1973 except partial modification due to the construction of Chungju multipurpose dam in 1985. The water level near the downstream of Paldang dam has been lowered about 3 m because of the channel maintenance of Han River development project. Thus, the discharge estimation formula based on the submerged orifice type spillway has to be re-evaluated by considering various patterns of the gate operation rules and lowered channel bed. In this study, three types of gate openings were tested to select the proper gate operation rules through the hydraulic model test for various discharges and opening heights. Also, the numerical analysis has been performed to simulate the flow patterns of downstream. As a result, the gate operation rule, which opens 5 gates each time from the left side, was selected as the proper gate operation rule of Paldang dam.

• Journal of Korea Water Resources Association
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• v.45 no.9
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• pp.959-968
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• 2012

HEC-RAS has been applied to simulate water level variation in the Ara waterway during the flood season. To support decision making necessary for operation of the hydraulic structures especially during the flood season, it is important to consider various factors such as water level of the Han River, Gulpo River, and tidal level of the west sea in conjunction with operation of the hydraulic structures such as the Gyulhyun Weir, the West sea gate, and pumping stations. Especially for operation of the west sea gate, the Rule-script option was employed to determine the opening height considering the variation of the water level in the waterway and the west sea simultaneously. For model verification, comparison of water level computed at the upstream and downstream of the regulation weir shows a good agreement with observed data measured during the flood event in September 2010. The HEC-RAS model developed in this study will contribute to support operation of the waterway during the flood season.

• Journal of Korea Water Resources Association
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• v.33 no.2
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• pp.237-245
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• 2000

Sihwa seadike is originally designed to control the water level In lake Sihwa. However the sluice gate is being operated everyday to preserve the water quality of lake. Due to the frequent operation of gates the bottom of drainage canal which is composed of weathered rock and soft rock is being scoured. Recently the bottom in the front area of apron was protected by putting underwater concrete. This study is carried out to understand the hydraulic situation for protection, and to estimate the trend of scouring by comparing between energy dissipation and registance of bottom rock. Annandale(1995) introduced the erodibility index theory, and suggested a criteria to judge the erodibility of rock through the relation between the erodibility index and energy dissipation. Determenation of erodibility index of rock is based on the results of sample core analysis, and the energy dissipation of flow is calculated from the estimation of total head on the scale model. These two values are plotted on the criteria, and the erodibility of rock is determined.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.4
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• pp.269-279
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• 2005

Numerical simulations were done using depth integrated ADCIRC model in order to evaluate dynamic response on the inner Saemankeum reservoir due to flood flow and gate operation for the both situations of dike construction and inner development. According to 2-dimensional dynamic flood routing, temporal variation of hydrographs shows sensitive at upstream riverine region while it becomes stable from the center part of the reservoir due to sudden expansion of physical changes. Dynamic response of hydraulic changes such as water surface elevation and velocity on the inner region arises suddenly by gate operation and more rapidly after the inner development than dike construction. Temporal surface fluctuation arises during inflowging of outer sea water and propagates upstream up to 10km to 16km in accordance with inner development status.

• Ecology and Resilient Infrastructure
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• v.5 no.4
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• pp.276-284
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• 2018

In order to analyze sediment transport characteristics of knickpoint migration, sediment transport length, and sediment transport weight through the under-flow type vertical lift gate, the hydraulic model experiment and dimensional analysis were performed. The correlations between Froude number and sediment transport characteristics were schematized. The multiple regression formulae for sediment transport characteristics with non-dimensional parameters were suggested. The determination coefficients of multiple regression equations appeared high as 0.618 for knickpoint migration, 0.632 for sediment transport length, and 0.866 for sediment transport weight. In order to evaluate the applicability of the developed hydraulic characteristic equations, 95% prediction interval analysis was conducted on the measured and the calculated by multiple regression equations, and it was determined that NSE (Nash-Sutcliffe Efficiency), RMSE (root mean square), and MAPE (mean absolute percentage error) are appropriate, for the accuracy analysis related to the prediction on sediment transport characteristics of kickpoint migration, sediment transport length and weight.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.89-98
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• 2006

In this study, a method for flood runoff analysis in main channel connected with interior floodplain, is applied for evaluation of hydraulics of Sapgyo lake for the purpose of flood protection by considering tidal effect of West Sea and runoff from the watershed. Especially, operational condition of sluice gate was explicitly modeled in conjunction with various runoff scenarios from watershed. The change in hydraulics of main channel and interior floodplain was found to be predominantly affected by tidal effect, and explicit modeling of gate operation made possible the evaluation of hydraulic characteristics of different alternatives. Until now, such an analysis was not made due to the lack of models with such capability, however, with the proposed method, it is possible to perform such an analysis and is thought that the proposed method can be a valuable tool for flood protection planning.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2460-2468
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• 2014

A local rain that is concentrated in specific area in a short time frequently occurs due to recent abnormal weather. To prevent potential flood disasters, therefore, it is necessary to be established to the flood control system. Checking the river design standard, however, hydrologic design frequency of water gate is only marked as over 20 years, so this fact shows that the standard is unclear. The inland inundation modeling considering the stage in a river and quantitative assessment are required to reduce flood damage. The simulation for internal inundation is very complex and is time-consuming due to considering hydraulic hydrology characteristics at the same time. Using the already established river master plan, consequently, this study proposed the simple and convenient method for assessment of the internal inundation simulation. Using the proposed method in the upper and middle regions of a river, influences for design frequency or water gate location were assessed by applying the nine probability precipitation with design frequency and by targeting the water gates which are installed in five inlands.

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.971-984
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• 2003

This paper presents the hydraulic analysis of the air entrainment by the weir types. For the weir types, the stepped weir, the labyrinth weir and the gate underflow weir were selected, and the oxygen transfer efficiency was estimated by the site investigation and the hydraulic model tests. The most effective type for the oxygen transfer was stepped weir The more steps the stepped weir had, the higher efficiency it revealed. Oxygen transfer was proportional to the flow velocity, the Froude number, and the flow discharge in order. Hydraulic model tests showed that a nappe flow occurred at small flow rates. The concurrent condition of a nappe flow and a skimming flow occurred as flow rate increases, nappe flow at the upper part and skimming flow at the lower part. In the region of nappe flow, air inception occurred from the step edges due to flow separation, and air entrainment was made through a free-falling nappe, an air pocket, a nappe impact and a subsequent hydraulic jump. In the region of skimming flow, air entrainment occurred by the variation of water surface over the steps, but it was relatively small compared with nappe flow.