• Water for future
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• v.27 no.4
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• pp.115-121
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• 1994

In tidal rivers, the water level is affected by a tidal wave. The latter creates higher flood stages that enlarge the flood plain areas and increase potential damages. In such rivers, the water level is not solely a function of the flow discharge but rather a joint function of both the discharge and tidal phenomena. This paper attempts at formulating a relation between tital water level and river flow discharge that can be used for the predictions of water level in coastal rivers. Numerical applications were performed on the HaDong and the SongJung Station in Sumjin river with satisfactory results. The correlation coefficients between the tide(M) and the water stage(Z) at the HaDong Station is 0.558, and SongJung is 0.016. From this result, the water level at HaDong Station is greatly affected by a tide, whereas songJung is not.

• Water for future
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• v.22 no.1
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• pp.99-107
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• 1989

KEUM River downstream has some characteristics in which the dowunstream is affected with tidal motion, the several tributaries are forming a dendritic river system, and the channel cross-sections are irregular. The flood in this downstream can now be analyzed by the hydrological flood routing methods and under the assumption regarding the dendritic river system as a single reach. In this study the river system was used for the flood routing. The flood records which were measured in 1978 and 1987 were applied for calibration and verification of the unsteady flow model respectively. The results show that the flood at KANG-KYONG station was not affected with the tidal motion when the discharge at KONG-JU station exceeded about 5, 000$m^3$/sec, and that the bottle neck at IP-PO station intercepted the tidal influences.

• Journal of Korea Water Resources Association
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• v.31 no.3
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• pp.235-242
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• 1998

The objective of this study is to develope a predictive model for flood forecasting in the tidal reaches of the Nakdong river and to analyze the tidal effects of major flood forecasting station of the Nakdong river by using the hydraulic flood routing. In the calibration process the optimum roughness coefficients as functions of channel reach and discharge were determined and the calibration results suggest that the unsteady hydraulic flood routing model simulated with the optimum roughness coefficients showed close agreement between the calculated and observed stage.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1138-1142
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• 2005

The tidal river is a river affected by tide, which causes the water level to rise and fall two times everyday periodically. The local velocity across the river could be very fast because of the cross-sectional characteristics of the river even though it's not a rainy season. Therefore extreme local scour could take place around hydraulic structures such as piers and caissons due to backward flow velocity. For the construction of pier foundation of Ilsan-bridge In the Han River, the field observations were performed to get the velocity and water level. The numerical analysis was performed by HEC-RAS(UNET). The relationship between measured maximum velocity and calculated mean velocity is achieved, which is used to estimate the velocity and water level as the construction is proceeding. Countermeasures for scour were designed with the results of the hydraulic analysis to avoid potential damage during construction work. According to the results of monitoring, the velocity increase after temporary road embankment was negligible, from which it is considered that the degradation of main channel compensated for the constriction of cross-section by embankment.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.318-321
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• 2004

The damage scale and damage area in the coast have been increased dramatically because of calamities such as typhoon. tidal wave. flood and storm. Especially. 409 cases. which reach to about $40.9\%$ of natural disasters of 1,000 cases for the recent 15 years have happened on coast area. More than $40\%$ of natural disasters also occurred every year is happening in coastland. Therefore, there is a great need to construct all related GIS database such as atmospheric phenomena (typhoon. tidal wave, flood and storm). harbor facility, harbor traffic and ebb and flow. Furthermore. the certain system should be developed and integrated with NDMS (National Disaster Management System) by using 3D web GIS technology. In this study. the coast disaster area management system was designed and developed by using 3D web GIS technique so that the coast disaster area could be monitored and managed in real time and in visual. Finally. the future disaster in coast area could be predicted scientifically.

• Water for future
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• v.24 no.2
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• pp.81-95
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• 1991

For investigation of the interaction of tide and river flow, the derived equations are solved analytically using the approximation method of perturbation. The convective inertia and nonlinear bottom friction terms are included in the derivations. The harmonic analysis is applied to decompose the complicated interaction of the freshwater discharge with various constituents of tide into its individual interaction with each constituent. In this study, four main constituents(M2, S2, Kl, 01) are included. The relations of dimensionless parameters of the tide, especially the dimensionless damping modulus, are then determined for each solution. The results show that analytical solution of dimensionless damping modulus underestimates the measured value obtained from harmonic analysis. Results of water level obtained by applying the analytical model to a tidal reach of the Keum River in the years 1981 and 1982 show very good agreement with those obtained from the harmonic analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.847-857
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• 1994

FESWMS-2DH developed by the U.S. Department of Transportation based on two-dimensional shallow water wave equation is used in this study to simulate the flow characteristecs of the river reach between Chamsil and Shingok submerged weirs, which acts as a tidal river under low flow conditions. The model uses Galerkin F.E.M and meshes are composed of triangular or quadrangular elements. The model shows accurate and stable results concerning mass conservation as well as velocity distribution and water surface elevation. The results obtained in the present study may provide useful informations on the planning of river pollution abatement measures and artificial structures.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1689-1693
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• 2008

서해안은 최대 조석 차 9 m 이상의 세계적으로 손꼽히는 반일조 지역이므로 염수가 신곡수중 보까지 치고 올라오는 것으로 알려져 있으나 한강 하구부에서의 흐름 및 염도분포 해석에 관한 연구는 지형적 군사적 특성 상 많이 진행되지 못했다. 본 연구에서는 2차원 하천해석 프로그램인 RAMS를 적용하여 신곡수중보 하류로부터 유도지점까지의 염도 분포 및 염수 길이를 해석하고 경험식을 이용해 수치모의 결과를 검증하였다. 염수가 최상류까지 치고 올라갈 수 있는 조건으로 최대조위와 최소유량을 가지는 시점을 택해 염도분포 농도를 계산하였으며 하류단인 유도지점의 염도를 인천검조소 실측값으로부터 전이하기 위해 이송분산방정식의 연속주입 해석해를 이용하였다. 염도분포의 최선단부는 장항 IC 부근으로 최대 역류 발생 위치와 같은 지점이었으며 정상염수 쐐기 경험식에 의해 염수의 길이를 해석한 결과와도 일치하였다.

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.135-146
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• 2007

FLDWAV model was modified such that it can adequately simulate the effect of Jamsil and Singok submerged weirs in the main reach of the Han River. The enhanced model combines weir-type discharge equations for overflow at fixed weir and Manning equation for fluvial-type flow at the movable weir. Equations for weir overflow include those for submerged weir flow and free overflow. Gates of the movable weir may be open or closed for the simulation. In order to test the simulation capabilities, the enhanced model was applied for various flow conditions at submerged weirs. Backwater effect due to Jamsil and Singok submerged weirs were well simulated. Simulations were carried out for spring and neap tides extracted from artificial tide generated by combining $M_2\;and\;S_2$ tidal constituents. Simulation results cleared indicated that tidal effect extends further upstream as the flood discharge decreases. Low flow simulation capabilities of the enhanced model was tested. Discontinuities of water surface elevation due to the submerged weirs were successively simulated.

• Korean Journal of Ecology and Environment
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• v.34 no.4 s.96
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• pp.267-276
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• 2001

The downstream reach of the Han River adjoining Seoul in Korea was the upper boundary of an estuary where tidal effect on the flow rate could be exerted. According to the comprehensive river regulation project, the river was channelize dand impounded by two overflow dams, which provided favorable condition for algal growth in this sewage polluted eutrophic reach. In this study primary productivity of phytoplankton was measured in the down reach and the autochthonous and allochthonous organic carbon loadings were estimated. Primary production of phytoplankton measured by C-14 uptake and P-I model method ranged from 140 to $4,890\;mgC\;m^{-2}\;d^{-1}$ (median value $1,865\;mgC\;m^{-2}\;d^{-1}$) showing the level of eutrophic lakes. Phytoplankton density that varied according to water flow rate was highest in spring. Allochthonous organic carbon loading was dominated by sewage input through tributaries in most of days except flood flow period. The average proportion of autochthonous carbon generation by phytoplankton was 40.9%, which is very high proportion for a lotic habitat.