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Computed M 2 tidal chart of the Yellow and East China Seas after the Saemankeum tidal barrage construction.
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A depth-averaged two-dimensional numerical model has been established in order to investigate tidal regime change by the large scale of reclamation in the west coast of Korean Peninsula. The fetched variable-grid system was used to discretize the complicated coastal region efficiently. Maximum six month integration of the model was carried to inves...
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... computation has been carried out with tidal barrage completed, as shown in Fig.3b. The M 2 computed tidal chart after tidal barrage is completed, is presented in Fig.5. The tidal chart does not look much different from the existing tidal pattern at a first glance, since the difference is relatively small. ...
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The tides in the Taiwan Strait (TS) feature large
semidiurnal lunar (M2) amplitudes. An extended Taylor method is
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depth, and the Coriolis force and bottom friction are retained in the
governing equations. Th...
Citations
... The simulated M2 decreased by approximately 4%, and M4 increased by 38%. Suh et al (2014) showed that several tidal reclamations increased the amplitude of M2 on the west coast of Korea, and the construction of the Saemangeum sea-wall decreased the amplitude of M2 around the Gunsan of South Korea (Kang et al 2013). Li et al (2018) also investigated the effect of accumulated reclamation on tides in the Xiangshan Bay, China, resulting in decrease in M2 amplitude by 6% and increase in M4 amplitude by 27%. ...
Because many coastal developments have been continuously occurred in the Yellow and the East China Sea, it is necessary to analyze the effect of persistent topographic change. This study simulated the tidal change in response to stepwise tidal flat reclamation in East China and the Yellow Sea using the MOdelo HIDrodinâmico (MOHID) ocean model. Based on previous studies and historical coastal information maps, we conducted several numerical experiments with reliable coastal topography changes around two areas (Jiangsu Shoalwater and Gyeonggi Bay) from 1990 to 1994 when the most active development took place. The results show that, unlike other components (S2, O1, and K1), the simulated amplitude of the M2 constituent significantly increased with the disappearance of the tidal flat in the Yellow Sea. At the same time, it decreased in the East China Sea. These results are consistent with the quantile regression analysis using observational data. We also found an accumulating effect of tidal energy flux when the reclamation continued, which does not appear in the previous studies. These results indicate persistent man-made tidal flat reclamation in a specific area can cause more remarkable regional tidal changes through tidal energy redistribution and modification.
... If the sediment plume is formed during flood tides, muddy sediments are highly likely to be transported northward to the tidal flats. Flood-dominant tidal asymmetry appears to facilitate mud deposition in the tidal flats (Kang et al., 2013;MOF, 2019b). Dredging activity inside the dike to build roads increased the SSCs of effluent water. ...
The morphodynamics of tidal flats responds mainly to the nonlinear interaction between tides and seasonal wave activity. Man-made activities such as reclamation further complicate the morphodynamics by disturbing physical processes acting on the tidal flats. Decoupling the anthropogenic influence from the natural forcing on the tidal-flat morphodynamics is crucial in assessing the adverse effects of man-made activities. Still, it remains a challenge due to inherent difficulties in characterizing spatiotemporal variability of the tidal-flat morphology. A three-year-long field survey using unmanned aviation vehicle (UAV)-assisted photogrammetry, sedimentological and benthic fauna data was conducted on the Shinsi tidal flats near the Saemangeum dike, west coast of Korea, to evaluate the relative significance between natural and anthropogenic influence on the morphologic changes of the tidal flats and benthic community structures. The Shinsi tidal flats exhibited non-seasonal sedimentation patterns and experienced overall erosion despite their sheltered location from the offshore waves. The Saemangeum dike contributed to the sustained erosion by reflecting offshore waves toward the tidal flats during winter to spring. Heavy rainfalls also promoted erosion of the tidal flats in summer. The small-scale embankments complicated the spatial sedimentation trend by protecting tidal flats from offshore waves or promoting erosion with shoaling waves. Notable mud deposition occurred during winter, incompatible with the general hydrodynamic condition, resulting from intensive dredging activity inside and outside the Saemanguem dike. The proliferation of the opportunistic species followed the mud deposition for several months until the enhanced wave activity removed the muddy sediments from the flats. Overall erosion dominance and the temporary occurrence of opportunistic species imply that the Shinsi tidal flats are subject to non-seasonal changes in sedimentology and morphology due to artificial structures and man-made activity, leading to the instability of the benthic communities in the tidal flats.
... Similarly, tidal prism and high tide level are also changed and tidal range of the M 2 tidal component is increased due to the dike building and reclamation in the Mokpo Bay in South Korea [6]. Some studies on tidal flat reclamation in the open coast have discussed tide variations through analysing the changes of [7][8][9][10]. Generally speaking, tidal component amplitudes in the nearshore area of seawalls will be increased or decreased, which will reflect the high tide level, but the reasons for these changes have not been fully explained. ...
Wenzhou Bay, which is located in the southern coast of China with rich tidal flat resources, is frequently influenced by human activities, leading coastline deformation and high tide level changes in estuary area. A two-dimensional tidal numerical model of high resolution including Wenzhou Bay and East China Sea was established based on the MIKE21 FM model. The model was calibrated with field data and then was employed to predict high tide level changes under the development plan of coastline deformation. According to the simulating results, high tide level and tidal range in the Ou River and the Feiyun River estuary area will decrease about 0.01~0.13 m and 0.01~0.18 m, whether in dry season or flood season. Further analysis from tide wave point illustrates that weaken of the tidal system outside estuary area will occur after the coastline deformation. The direction of tidal propagation will change from vertical to parallel to coastline, causing weaken reflection, leading to the decreases of tidal range and high tidal level.
... The increases are not monotonic, however; beyond a critical depth, it is possible for the tidal amplitudes to reduce as the progressive tidal wave transitions to a standing wave. Local anthropogenic effects (reclamation, shoreline changes, etc.) have also been shown to impact not only tidal currents (e.g., [46]), but also tidal amplitudes [43,63]. At a larger scale, the effect of continental shelf width (and depth) on tidal amplitudes has been considered (e.g., [2,3,5,15,17])). ...
Tidal range is one factor in determining the vertical location of local mean sea level, and it is also a contributor to total water levels and coastal flooding. It is therefore important to understand both the spatial distribution of tidal range and the temporal variation in tidal range, over a wide range of scales. Knowledge of historic tidal range is obtained both through observations and through modeling. This paper reviews numerous observational and modeling studies of historic tidal range variations on decadal to millennial timescales. It also discusses many of the physical processes that are responsible for these variations. Finally, this paper concludes with discussion of several modeling studies that seek to constrain future changes in tidal range in coastal environments.
... If all of the extreme surge values post-2001 were reduced by 5 cm (as the worst case scenario) it would not materially change the relative position of the 2001-10 surges as being extreme in terms of the rest of the series, nor in the periodicities identified. Tidal range and hence elevations of both MHWS and MLWS may shift as a function of: rising MSL (Pugh and Woodworth, 2014); coastal geomorphology of the site (Mawdsley et al., 2015); and anthropogenic alteration of the basin/channel in which tidal observations are taken (Kang et al., 2013;Pethick and Orford, 2013). Such changes if not recognised may add/subtract to atmospheric surge component. ...
... Many investigations have been conducted to ascertain the temporal-spatial distribution and variation of the tidal system in the "ridge-channel" offshore area. Several numerical studies using bathymetric data (Zhu and Chen, 2005;Wang et al., 2011a;Xing et al., 2011;Kang et al., 2013;Song et al., 2013;Zhang et al., 2013) confi rmed that there is a stable radial tidal current fi eld acting as the main dynamic factor in the formation and evolution of the radial sand ridges. Two large scale fi eld surveys (Ren, 1986;Zhang, 2013) also proved the existence of this radial tidal current fi eld. ...
The radial tidal current field accounts for the formation of the radial sand ridges in the South Yellow Sea. Understanding the formation and evolution of this radial tidal current field is vital to assessing the morphodynamic features in the area. A semi-enclosed rectangular basin with and without a coastal barrier was schematized from the topography of the Bohai Sea and Yellow Sea. The 2D tidal current field in this basin was simulated using the DELFT3D-FLOW model. The concept of tidal wave refraction, which highlights the effect of the sloped or stepped submarine topography on the propagation of the tidal waves, was introduced to explain the formation of the radial tidal current field. Under the effect of tidal wave refraction, co-phase lines of the counterclockwise rotating tidal wave and incident tidal wave are transformed into clockwise and counterclockwise deflections, respectively, leading to the convergence and divergence of the flow field. Regardless of whether a coastal barrier exists or not, the outer radial tidal current field might emerge over certain topography. The responses of the radial tidal current field in this basin to the environmental variations such as coastline changes and bottom erosions were discussed. Results show that local protrusion near the focal point of the radial tidal current field will have limited effects on the location of the tidal system. However, a remarkable shift of the amphidromic point toward the entrance and central axis of this basin and a movement of the focal point of the radial tidal current field toward the entrance could be caused by the significant seaward coastline advance and submarine slope erosion.
... Another case, case REC, in which a new coastline is adopted to represent the condition after the reclamation of the radial sand ridges (Fig. 9), is compared with case OM to investigate the near-field effect of reclamation on the tidal regime. The open boundaries are located sufficiently far away from the reclamation region, to inhibit the disturbance of open boundaries as Kang et al. [2013] suggested. ...
... Previous studies suggest that the SDP is important for the formation of the rotating tidal wave system and then the RTC field in the southern Yellow Sea [e.g. Choi, 1980;Zhang and Zhang, 1996;Wang et al., 1998;Zhang et al., 1998;Wang et al., 2012;Kang et al., 1998;Kang et al., 2013]. However, there has not yet a discussion or verification been made on this point of view. ...
To investigate the near-field and far-field hydrodynamic conditions along the Jiangsu Coast in large scale, a two-dimensional tidal wave model which covers the Bohai Sea, the Yellow Sea and the East China Sea is developed and validated. After a brief review of previous models, some influencing factors, such as tide generating force, river discharges as well as shoreline changes due to land reclamation, are examined in this study. We suggest that whether these factors should be considered in the model depends on the different purposes and geographical regions of interest. Then, a series of experiments are designed to further investigate the previously proposed important factors of influence [i.e. local bathymetry and the role of Shandong Peninsula (SDP)] on the tidal motions in the Yellow Sea. The numerical experimental results show that the interaction between the tidal wave system in the northern Yellow Sea and the incoming tidal wave plays a main role on the formation of the rotating tidal wave system in the southern Yellow Sea, whereas the role of geometric position of the SDP is secondary. With respect to the tidal current, it is found that the radial shape of it is independent of the local bathymetry, but may be generated by the convergent tidal wave formed by the meeting of the rotating tidal wave in the southern Yellow Sea and the incoming tidal wave from the East China Sea. Furthermore, a certain water depth is crucial for the intensity of current velocity to generate the special topography of radial sand ridges. © 2015 World Scientific Publishing Company and Japan Society of Civil Engineers.
... Verification of the cause of the changes of the tides along the German and Dutch coast is not possible with the GESLA dataset since no high-resolution sea level data are available before the start of the Deltaworks. A modeling study by Kang et al. [2013] of the Yellow Sea showed that the tidal regime there changed in response to large-scale land reclamation on the Korean coast. ...
Tides exert a major control on the coastal zone by influencing high sea levels and coastal flooding, navigation, sediment dynamics and ecology. Therefore, any changes to tides have wide ranging and important implications. In this paper, we uniquely assess secular changes in 15 regularly used tidal levels (five high water, five low water and five tidal ranges), which have direct practical applications. Using sea level data from 220 tide gauge sites, we found changes have occured in all analysed tidal levels in many parts of the world. For the tidal levels assessed, between 36% and 63% of sites had trends significantly different (at 95% confidence level) from zero. At certain locations, the magnitude of the trends in tidal levels were similar to trends in mean sea level over the last century, with observed changes in tidal range and high water levels of over 5mm/yr and 2mm/yr respectively. More positive than negative trends were observed in tidal ranges and high water levels, and vice versa for low water levels. However we found no significant correlation between trends in mean sea level and any tidal levels. Spatially coherent trends were observed in some regions, including the north-east Pacific, German Bight and Australasia, and we also found that differences in trends occur between different tidal levels. This implies that analysing different tidal levels is important. Because changes in the tide are widespread and of similar magnitude to mean sea level rise at a number sites, changes in tides should be considered in coastal risk assessments.
... Its impacts spread so wide that they reached the WCK. Suh (2009) and Kang et al. (2013) dealt with tidal regime variations caused by the Saemangeum reclamation project. Their results showed a reduction in semi-diurnal amplitudes in the near-field area but a slight amplification in the far-field area on the Shandong Peninsula. ...
... Although this grid had not quite sufficient to resolve present study, finer gridding developed. Since nodal distribution depend reproduction (Suh, 2011), 38% of and 14.5% to 10 to 20 m depths shallow coastal areas in NWP of interest associated with land reclamation were 420-1200 m, 310-1400 m were reduced to 290-1100 m 430 m), respectively, in NWP- Coastal ocean circulation models have been intensively applied to the YS from FDM with coarse grid resolution (Choi, 1980) was applied, while or Finite Volume Method (FVM) models have been applied to represent the complex geometry in recent years (Suh, 2009;Kang et al., 2013; the FEM model ADCIRC. ...
... Topological data were based on (Amante and Eakins, 2009) and the General Bathymetric Chart of the Ocean IOC, 2012). Forcing functions were prescribed in the whole inner domain tidal asymmetry at the 7 major tidal stations on the WCK amplitudes (solid line) and phases (dashed line), variation and relative phase intensively applied to the YS from the late 1970s ) was applied, while models have been applied to Kang et al., 2013; was applied, denoting an ly 57k nodes (Suh, n the shallow region, the resolution was especially on the WCK. Thus, in the G116k and NWP-G258k were tidal hydrodynamic less than 10 m deep, were used to represent around the major regions and Mokpo areas, G57k. ...
At least 19 remarkable dikes and land reclamations have been constructed since 1970 along the west coast of Korea, which resulted in a reduction in tidal flat area of almost 50%. Both the reduction in tidal flats and the artificially simplified coastal line have distorted the spatio-temporal tidal hydrodynamics; to quantify this, we analyzed and evaluated tidal asymmetry by phase differences of the principal semi-diurnal lunar constituent M2 and its first over-tide M4. Moreover, we applied the ADCIRC model to quantitatively investigate near- and far-field impacts on tidal variations using the gamma parameter, tidal energy flux, and dissipation rate. Through this study, we found that the tidal regime around the Incheon harbor area in Gyeonggi Bay has changed from ebb-to flood-dominant due to multiple nearby reclamations, in particular to the construction of the Siwha dike. The Saemangeum dike caused near-field de-amplification of M2 but far-field amplification in the Shandong area of China. In addition to allowing a traditional asymmetry approach using phase difference, analyses based on the gamma parameter and tidal energy variations could distinctly improve spatial understanding of anthropogenic impacts on coastal tidal hydrodynamics.
... The changes in tidal regime are mainly due to the extensive shoreline changes from land reclamation along both the Chinese and Korean coasts. The impact of these changes is not localized near the reclamation areas (Jang et al., 2012) but rather is present in the entire basin due to the redistribution of tidal energy (Song et al., 2013;Kang et al., 2013). ...
