• Journal of Korean Society of Coastal and Ocean Engineers
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• v.2 no.1
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• pp.34-42
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• 1990

The tides in the Saemanguem Area, the western coast of Korea have been examined based on simulations with barotropic depth-integrated model. As a first step tidal computations were performed with open-boundary sea level forcing from four major constitutents ($M_2$, $S_2$, $K_1$, and $O_1$). Subsequently the established model was utilized to investigate the effect of construction of tidal barriers for Saemanguem development plan on the existing tidal regime. It has been shown that tide of semi-diurnal constituents may be reduced to 2-7 cm in amplitude along the frontal area of proposed barrier. In connection with above changes the tidal current regime may be subjected to significant reduction in intensity. thus suggesting the high possibility of sedimentation along the frontal region of tidal barrier.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.4
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• pp.231-242
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• 1992

This study uses a numerical model to investigate the circulation patterns of the tidal and wind driven current components. The model is vertically averaged 2-D transient using explicit nume-rical scheme, based on equation of motion and continuity. forced by water elevation at open boundaries and wind stress. The model domain extends from 35$^{\circ}$N to 36$^{\circ}$40'N lat., and 125$^{\circ}$E to 126$^{\circ}$40'E long. with x, y grid spacing of 5 km. The model reproduces the tide and tidal currents by 4 major constituents successfully with more than 90% accuracy when compared to two offshore tidal records and currents at one offshore measurements for 22 days. Responses of coastal waters to six schematic wind events are analyzed in terms of current distribution patterns and local features. Regardless of wind directions. strong coastal currents were produced. Bottom topography plays a critical role in producing a local eddy Held whose center is located offshore Pu An with its major radius of 40 km.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.5
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• pp.319-325
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• 2012

A new formulae for the estimation of the exposure duration in the inter-tidal zone are developed. The exposure duration is one of the most important factors influencing the habitat distribution of the benthic organisms. The formulae can estimate the exposure duration only using the four major tidal harmonic constants available in almost coastal areas. It is easier than the existing method using the frequency analysis of the hourly tidal elevation data. The estimation results by using the formulae suggested in this study are compared with the value by using the observed tidal elevation data analysis in the west coast, Korea. The mean RMS (root-mean squared) errors ranged form 0.8 to 1.4%. It can be used to simply estimate the accurate exposure duration in the region not having the longterm hourly tidal elevation data.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.4
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• pp.27-40
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• 2002

The circulation of sea water was simulated by two dimensional tide model using the main four tidal components and permanent current driven by inflow/outflow across open boundaries. According to the residt of tide model, the maximum speed of eastward flow on the Cheju Strait is twice higher than that of westward flow. According to the result of permanent current, the flow of permanent current showing semi-circle pattern in the southern part of Kojedo was due to variation of topography. According to the result of circulation model in the Cheju Strait, eastward flow entering in the southern waters from the Yellow Sea of Korea were dominant, but outflows westward were weak. These results suggest that it was difficult to move for suspended particulate matter into the Yellow sea from the southern waters through Cheju Strait.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.4
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• pp.495-508
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• 2019

Tidal datums are key and basic information used in fields of navigation, coastal structures' design, maritime boundary delimitation and inundation warning. In Korea, the Approximate Lowest Low Water (ALLW) and the Approximate Highest High Water (AHHW) have been used as levels of tidal datums for depth, coastline and vertical clearances in hydrography and coastal engineering fields. However, recently the major maritime countries including USA, Australia and UK have adopted the Lowest Astronomical Tide (LAT) and the Highest Astronomical Tide (HAT) as the tidal datums. In this study, 1-hr interval 19-year sea level records (1999-2017) observed at 9 tidal observation stations along the west and south coasts of Korea were used to calculate LAT and HAT for each station using 1-minute interval 19-year tidal prediction data yielded through three tidal harmonic methods: 19 year vector average of tidal harmonic constants (Vector Average Method, VA), tidal harmonic analysis on 19 years of continuous data (19-year Method, 19Y) and tidal harmonic analysis on one year of data (1-year Method, 1Y). The calculated LAT and HAT values were quantitatively compared with the ALLW and AHHW values, respectively. The main causes of the difference between them were explored. In this study, we used the UTide, which is capable of conducting 19-year record tidal harmonic analysis and 19 year tidal prediction. Application of the three harmonic methods showed that there were relatively small differences (mostly less than ±1 cm) of the values of LAT and HAT calculated from the VA and 19Y methods, revealing that each method can be mutually and effectively used. In contrast, the standard deviations between LATs and HATs calculated from the 1Y and 19Y methods were 3~7 cm. The LAT (HAT) differences between the 1Y and 19Y methods range from -16.4 to 10.7 cm (-8.2 to 14.3 cm), which are relatively large compared to the LAT and HAT differences between the VA and 19Y methods. The LAT (HAT) values are, on average, 33.6 (46.2) cm lower (higher) than those of ALLW (AHHW) along the west and south coast of Korea. It was found that the S_a and N₂ tides significantly contribute to these differences. In the shallow water constituents dominated area, the M₄ and MS₄ tides also remarkably contribute to them. Differences between the LAT and the ALLW are larger than those between the HAT and the AHHW. The asymmetry occurs because the LAT and HAT are calculated from the amplitudes and phase-lags of 67 harmonic constituents whereas the ALLW and AHHW are based only on the amplitudes of the 4 major harmonic constituents.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.2
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• pp.93-100
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• 1999

Analyzing the tide data taken at Kunsan inner and Outer ports, non-tidal and mean sea level and harmonic constants of major constituents are investigated to examine the effects of the dyke gate operation on the sea level change in Keum River estuary. Non-tidal and annual mean sea levels decrease at Kunsan Inner and Outer ports after the dyke gate operation, especially showing an abrupt drop of non-tidal sea level at Kunsan Inner port. This non-tidal sea level drop results in the mean sea level gradient change between the inner and outer port, which can be mainly explained in terms of the decrease of river discharge from the dyke. Amplitudes of the $M_2$ and $S_2$ tides at the Inner port increase after the dyke gate operation, showing an abrupt jump, and phases of both tides slightly decrease. Amplitude and phase of the $K_1$ and $O_1$ tides show slight changes after the dyke gate operation. This significant change of semi diurnal tide amplitude is believed as a result of superposition of incident tidal wave and reflected tidal wave from the dyke.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.5
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• pp.393-400
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• 2011

The mass transport is very complicated at the area which has the macro tide and complex geometry such as Gyeonggi bay. Especially, the long period current has a strong influence on the estuarine ecosystem and the long-term distribution of substances. The long period current is caused by several external forcing, whose unique characteristic varies spatially and temporally. The variation characteristics of long period current is analysed and its generation mechanism is studied. The tidal nonlinear constituents such as overtide and compound tide are generated due to nonlinear interaction and it causes mean sea level setup. The tidal wave propagating up into estuary is transformed rapidly by decrease of cross-sectional area and depth. Therefore the mean sea level is getting rise toward upriver. The high and low tide level is similar between down-river(Incheon) and up-river(Ganghwa) during neap tide when the tidal deformation is decreased. The tidal phase difference between two tidal stations causes a periodic fluctuation of sea level difference. The low water level of Ganghwa station during spring tide does not descend under EL(-)2.5 m, but the low water level of Incheon fall down under EL(-)4.0 m. The variation of tidal range and its sea level are increased during spring tide. It is found that the long period current $M_{sf}$ is quite similar to that of sea level difference between the two tidal stations. It means that the sea surface inclination caused by the spatial difference of tidal deformation is important forcing for the generation of long period current.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.624-634
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• 1995

Tides at both of northern and southern entrances of Kamag Bay were compared by deploying tide gauges for 18 days during July-August 1994. To examine the response of the inner bay to the tidal waves through both entrances, a current meter was moored at the eastern pan of the inner bay. Current meter mooring failed at the northern entrance (Yosu) while the current data was collected for only 5 days at the southern site (Songdo). Maximum range was 357 and 352 cm at Yosu and Songdo, respectively. Respective amplitudes for M2, S2 Kl O1 tides of 95.5, 48.8, 20.5, 14.0cm at Yosu and 93.6, 47.2, 21.3, 13.1cm at Songdo yielded the form numbers of 0.23 and 0.24, respectively, both of which belong to the predominantly semidiurnal tide, Contributions from the overtides and compound tides were less than $4\%^ at both sites. Differences in Greenwich phase of major partial tides between two sites were negligible. Maximum speed of tidal current was about 100cm/sec at the southern entrance and about 40cm/sec at the inner bay. Residual current speed was 17cm/sec southwestward at the southern entrance and 0.9cm/sec southeastward at the inner bay. Temporal change in current at the inner bay showed that the wind had a significant influence upon the circulation in Kamag Bay.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.543-547
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• 2005

해수소통을 전제한 경우 새만금호 내측의 염분변화가 만경강의 평수량 및 홍수량 유입에 따라 혼합확산되는 것을 평가하고 배수갑문 방류시 담수가 외해에 미치는 영향범위를 평가하기 위한 수치모형실험이 실시되었다. 이때 새만금호 내부의 관리수위는 DL=-1.5m, DL=-0.5m, DL=-0.0m, DL=+0.5m가 고려되었다. 외해역의 평가는 새만금을 포함한 전체해역에 대해 외해경계에서 4개의 주요분조($M_2,S_2,K_1,O_1$)의 진폭과 위상각을 대입하고 2차원 ADCIRC 및 3차원 TIDE3D 모형을 적용하였다. 내부는 여기에 3개 연직층을 고려한 3차원 ICM 모델이 추가 적용되었다. 내부의 혼합확산 평가 결과는 시간이 지남에 따라 외해에서 유입되는 염수가 상대적으로 저염인 담수호 내부로 유입 확산되는 것이 평면적으로나 연직방향으로 변화되는 것을 매우 뚜렷하게 나타남을 알 수 있고, 최소 1개월 이상 경과되어야 만경호측에 외해수가 혼합되는 것으로 분석된다. 수문을 개방하지 않은 상태에서 새만금 방조제 외해의 최강창낙조시 조류속도는 0.5-0.6m/s 정도에 해당되는 것으로 분석되었다. 신시갑문을 개방하는 경우 관리수위가 DL=-1.5m와 DL=+0.5m로 변함에 따라 갑문 전면 10Km-l3Km에 이르는 해역까지 수문개방에 따라 0.5m/s의 유속이 형성된다. 가력갑문을 개방하는 경우는 신시갑문의 개방에 따른 영향보다는 작지만 갑문 전면 14Km까지 0.5m/s의 강한 유동이 관리수위별로 나타나고 있다. 이러한 결과는 담수 방류로 인한 영향이 주기적으로 낙조시에 발생되어 새만금 방조제 전면의 해수순환과 유동에 적지 않은 영향을 미칠 개연성을 제시하는 것으로 해석된다.$\cdot$유출에 의한 수질변화양상을 단계적으로 구분하여 수질변화에 중요한 영향을 미치는 인자에 대한 이론적인 분석을 수행하고, 배수갑문 개방에 의한 수질개선효과를 최대화하기 위한 환경관리 방안 제시에 중점을 두어 수행하였다.ncy), 환경성(environmental feasibility) 등을 정성적으로(qualitatively) 파악하여 실현가능한 대안을 선정하였다. 이렇게 선정된 대안들은 중유역별로 검토하여 효과가 있을 것으로 판단되는 대안들을 제시하는 예비타당성(Prefeasibility) 계획을 수립하였다. 이렇게 제시된 계획은 향후 과학적인 분석(세부평가방법)을 통해 대안을 평가하고 구체적인 타당성(feasibility) 계획을 수립하는데 토대가 될 것이다.{0.11R(mm)}(r^2=0.69)$로 나타났다. 이는 토양의 투수특성에 따라 강우량 증가에 비례하여 점증하는 침투수와 구분되는 현상이었다. 경사와 토양이 같은 조건에서 나지의 경우 역시 $Ro_{B10}(mm)=20.3e^{0.08R(mm)(r^2=0.84)$로 지수적으로 증가하는 경향을 나타내었다. 유거수량은 토성별로 양토를 1.0으로 기준할 때 사양토가 0.86으로 가장 작았고, 식양토 1.09, 식토 1.15로 평가되어 침투수에 비해 토성별 차이가 크게 나타났다. 이는 토성이 세립질일 수록 유거수의 저항이 작기 때문으로 생각된다. 경사에 따라서는 경사도가 증가할수록 증가하였으며 $10\% 경사일 때를 기준으로 $Ro(mm)=Ro_{10}{\times}0.797{\times}e^{-0.021s(\%)}$로 나타났다.천성 승모판 폐쇄 부전등을 초래하는 심

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1944-1947
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• 2008

강우기에 하천 유역에서의 탁수 발생은 대상 지역의 토양, 토지 이용형태와 식생 분포, 강우의 강도, 토지의 경사 등에 따라 큰 영향을 받게 된다. 본 연구에는 토지의 이용형태에 따른 강우 시 탁수 발생량을 평가하고자 용담댐 유역의 탁수 발생특성 조사를 실시하였다. 2005년의 조사지점은 유역면적이 가장 작은 주자천 유역과 구량천, 금강본류를 대상으로 하였다. 구량천과 금강본류는 용담댐 유역을 구성하는 가장 큰 두 소유역이며 다를 지역에 비해 오염원이 많아 용담댐수질에 많은 영향을 주는 하천이다. 현장조사는 6월 27일부터 7월 3일 까지 실시하였다. 2007년 조사 대상 지역은 주자천 유역의 주천교 지점과 금강본류 유역의 월곡교 지점을 선정하였다. 현장조사는 6월21${\sim}$22일, 9월14${\sim}$15일 2회에 걸쳐 실시하였으며 시간별 현장 탁도 측정 및 시료 채취를 통한 분석을 병행하였다. 2005년에 실시한 조사결과 오염원이 많고 유역이 넓은 천천은 7월 1일에 유입량이 최대로 348.16CMS였으며, 그날 탁도는 오후 2시 10분조사시에 최대 2060NTU를 나타냈다. 구량천은 같은날 조사를 실시하여 유량은 최대 200.33CMS였고, 최대 탁도는 763NTU를 나타냈다. 반면 주자천에서는 최대 탁도가 98.4NTU를 나타내 가장 탁도가 높은 금강본류와는 약 13배의 차이를 나타냈다. 2007년 1차 조사는 6월 21${\sim}$22일에 걸쳐 이루어 졌다. 주천교 지점은 시간최대 강우 17mm가 발생한 시점에 최대 92NTU의 탁도를 나타내었고 그 이후 감소하여 20NTU이하의 탁도를 유지하였다. 반면, 월곡교 지점은 시간최대 23mm의 강우가 발생하였고, 최대 탁도는 3,610NTU에 도달하였으며 1,000NTU이상의 고탁도가 6시간 이상 유지된 후, 시간이 지남에 따라 점차 감소하였다. 이러한 결과는 미개발지역인 주천교 지점의 경우 강우에 의한 탁수 발생이 상대적으로 적음을 보여주고 있으며 월곡교 지점과 같이 개발로 인해 노출된 토양의 경우 강우에 의해 쉽게 침식이 일어나 고탁도의 탁수를 발생시킴을 보여준다. 그러나 주천교지점에서 2005년에 조사한 자료와 비교해 보면 2007년이 적은 강우임에도 불구하고 탁도는 높게 나타난 결과를 나타내고 있으며 이는 토지이용의 고도화에 따른 영향으로 판단되었다. 연구 결과 유역내에서 탁수 발생은 같은 강도의 강우에 있어서 큰 차이를 보이고 있음을 확인할 수 있었다. 따라서 강우기에 저수지에서의 탁수 문제의 해결을 위해서는 상류 유역의 탁수 발생원 관리가 중요함을 보여주고 있으며, 토지 이용 형태에 따른 토양 침식 방지 대책이 강우기의 댐 내 탁도 문제를 개선할 수 있는 중요한 방안으로 판단된다.