• Ocean and Polar Research
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• v.27 no.4
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• pp.433-441
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• 2005

To investigate the characteristics of tidal currents and water circulation in the coastal waters off the Taean Peninsula, tidal currents and sea levels were measured at the study area from 1998 to 2004. In the central waterway to the south of Changan Sand Ridge, mean speed of tidal currents and residual currents were 74.0cm/s, 17.8cm/s respectively; the dominant residual currents flowed northeastward, and the amplitudes of semi-diurnal components $(M_2,\;S_2)$ were larger than diurnal components $(O_1,\;K_1)$. The flood and ebb tidal currents were northeastward and southwestward, respectively, and each period was about 6 hours for them, which was consistent with the period of sea levels at the study area. In the coastal region near Hakampo, Taean, mean velocities of tidal currents and residual currents were 46.1cm/s, 30.8cm/s respectively, and the dominant residual currents flowed southwestward. The amplitudes of shallow water constituents $(M_4,\;MS_4)$ were relatively laige, which were weaker to the northeastern coastal region off Mineodo. The northeastward flow continued for about $2{\sim}3$ hours, while the southwestward flow continued for about $9{\sim}10$ hours near Hakampo during the tidal period. Tidal currents flowed northeastward in the central area of the waterway during the period from the Low Water Level (LWL) to the High Water Level (HWL). While the currents in the coastal region flowed northeastward for the first 3 hours after the LWL, southwestward counter-currents flowed between 3 and 6 hours after the LWL. During the period from the HWL to the LWL, the dominant currents flowed southwestward in the study area except to the northeastern coastal region off Mineodo. Along the shorelines, the counter-currents flowed northward between 4 and 6 hours after the HWL. It seems that the counter-currents near the coastal region are caused by the topography and the geography of the shorelines at the study area.

• Journal of Korea Water Resources Association
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• v.45 no.11
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• pp.1093-1105
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• 2012

In this study, the simulations and analyses of flood flow due to a river inundation in a coastal urban area are carried out using a two-dimensional finite volume model with well-balanced HLLC scheme. The target area is a coastal urban area around Gohyun river which is located at Geoje city in Kyungnam province and was extremely damaged due to the heavy rainfall during the period of the typhoon "Maemi" in September 2003. For the purpose of the verification of the numerical model applied in this study, the simulated results are compared and analyzed with the inundation traces. In addition, the flood flow in an urban area is simulated and analyzed according to the scenarios of inflow variation due to the increase and decrease of the intensity of the heavy rainfall, which.

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2021.10a
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• pp.141-143
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• 2021

• Journal of Environmental Science International
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• v.20 no.9
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• pp.1141-1149
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• 2011

The three-dimensional hydrodynamic model was simulated to understand coastal sea front of formation and seasonal variation in the Southern Sea of Korea. In this study, we used to concept of stratification factor, to realize seasonal distribution of stratification coefficient which of seasonal residual flow, considered with, tide, wind and density effect. Tidal current tends to flow westward during the flood and eastward during ebb. The current by the wind stress showed to be much stronger the coastal than the offshore area in the surface layer. And the current by the horizontal gradient of water density showed to be relatively weak in the coastal area, with little seasonal differences. On the other hand, the flow in the offshore area showed results similar to that of the Tsushima Warm Current. The stratification factor (SHv) was calculated by taking into account the total flow of tide, wind and density effect. In summer, the calculated SHv distribution ranged from 2.0 to 2.5, similar to that of the coastal sea front. The horizontal temperature gradient showed to be strong during the winter, when the vertical stratification is weak. On the other hand, the horizontal gradient became weak in summer, during which vertical stratification is strong. Therefore, it is presume that the strength of vertical stratification and the horizontal temperature gradient affect the position of the coastal sea front.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.97-106
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• 2016

Since public facilities have high property values and are directly exposed to the flood hazard, they account for the highest share of disaster damages compared to other assets such as housing, industry, vehicle and agriculture in case of floods. Therefore, this study was conducted to develop and suggest the potential flood damage index for public facilities to evaluate potential flood damage of specific local government directly or indirectly as a tool for decision-making related to flood prevention, maintenance, management, and budget allocation. The flood damage assessment system proposed in this study was evaluated in 231 local governments nationwide. Evaluation results showed that higher values were obtained in Seoul metropolitan government, Gyeonggi-do (province), coastal areas in Gyeongsangnam-do (province), and Jeju island.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.151-162
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• 1980

To clarify the dispersion of pollutants introduced in the coastal region, a series of current measurements, the drogue and drift bottle experiments as well as the dye diffusion experiments were carried out in Onsan Bay and in the coastal waters of Ubong-ri near Ulsan. In the southeastern coastal region of Korean peninsula, that is, in the outside of Onsan Bay, the flood tidal current flows south-south-westward, and the ebb current flows north-north-eastward at a maximum speed of 1.0-1.1 knots at spring tide. In an inlet south of Cape Ubong, an anticyclonic eddy of 1 km in diameter is usually formed during both flood and ebb flows. The tidal current predominates in Onsan Bay at around spring tide. The maximum speed around spring tide was observed to be approximately 0.14 knot, while it was slower than 0.1 knot and variable at neap tide when the wind drift current played an important role. The flood tidal current flows westward while the ebb flow flows eastward in the northern region of the bay. The flood tidal current in the southern region of the bay flows west-north-westward, while the ebb current east-north-eastward. Wind drift currents in the coastal region of southern Korea are generally deduced to be southward in winter, the monthly mean speed being approximately 0.1 knot. Dye solution released at the northwestern corner in Onsan Bay was transported by eastward ebb tidal current toward the mouth of the bay dispersing by the wind. The apparent diffusion coefficient at 150 minutes after release in the bay was calculated to be $4.4\times10^4\;cm^2.sec^{-1}$, whereas that in the anticyclonic eddy was more or less smaller.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.2
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• pp.133-143
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• 1992

The water-quality control for coastal waters is continuously required in view point of the environmental protection. The purpose of this study is to simulate the hydrodynamic process and the dispersion phenomena of several pollutants in Suyeong Bay, Pusan. The present study employs the depth-averaged 2-dimensional model for nemerical simulation of the hydrodynamics and diffusion. The nemerical solution is obtained by ADI(Altenating Direction Implicit) scheme which is frequently used for tidal current and diffusion computations in the coastal zone. To verify the nunlerical results, the field observations of various water quality parameters such as COD, SS and nutrients were performed during the spring tide. In the results of this study, the computed tidal currents show the clockwise flows for ebb tide and counter-clockwise flows for flood tide. In comparison with the water-qualities in ebb tide and flood tide, there seems to be slightly deteriorated in ebb tide and especially near the estuary of Suyeong River. In flood tide, however, the water-quality near Kwangan Beach is deteriorated. The computed distributions of COD and SS are in god agreements with the observed ones, while those of $PO_4\;^{3-}-P\;and\;NO_3\;^--N$ show slight differences due to the complex transformation processes.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.187-187
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• 2016

High intensity of population distribution in deltaic setting especially in Asia tends to have increased and causes coastal flood risk due to lower elevations and significant subsidence. Maximum or peak discharge of flood always causes numerous deaths and huge economic losses. New technology of spatial satellite image has been applied to analyze flood damage. In this research, the relationship of nightlight intensity associated with flood damages has been determined during 1992-2013 with spatial resolution of 30 arc sec ($0.0083^{\circ}$) which is nearly one kilometer at the equator in whole six countries along the Mekong River (i.e., China, Myanmar, Lao PDR, Thailand, Cambodia and Vietnam). ArcGIS Hydrological Flow Length Tool has been used to determine the distance of each pixel areas from the rivers and streams. Statistical analysis results highlight the significant correlation R = 0.47 between nightlight digital number and economic damages per unit area (US$/km2) and R = 0.62 for number of affected people for unit area ($people/km^2$). The areas near by the Mekong River and its tributaries correspond to high flood damage. This spatial analysis result is going to be prestigious key information to the regions and all related stakeholders for decisions and mitigation strategies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.495-505
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• 2014

The retention basin is a river-facility for the flood mitigation by storing the river flow temporarily. The new 3 retention basins are installed in these regions YeoJu, NaJu, YoungWol by the Large River Management Project. In this study, 1D and 2D numerical flow simulation are conducted to evaluate the reduction effect of the peak flood stage for the YeoJu retention basin. HEC-RAS and FLDWAV models are used for 1D simulation with the option of retention basin. CCHE2D model is used for 2D simulation with the same hydrograph used in 1D simulation. It is verified that the peak flood stage is reduced very largely about 0.13 m near the overtopping section of the levee in 1D simulation. It is verified that the peak flood stage is reduced very largely about 0.20 m at the upstream-end of the simulated reach in 2D simulation. 2D simulation for the retention basin is more reasonable because physical characteristics of topography in the model, and also more advantageous for the evaluation of the flow characteristics of the in- and outside of the retention basin on the results of simulation of this study.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.447-452
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• 2001