• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.2
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• pp.121-129
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• 1992

A two-dimensional numerical tidal model is formulated to reproduce tides in the northeastern Yellow-Sea, Seohan Bay. The model was formulated on spherical grid system with mesh resolution of 1' latitude by 4/3' longitude. As a first step, tidal distribution of four major tidal constituents are computed and compared with coastal observation. Independent tidal charts for the M$_2$, S$_2$, $K_1$, and $O_1$ tides were presented. Residual tidal currents and tidal energy flux were also computed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.168-173
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• 2014

The effect of critical minimum depth in the coastal region on storm surges was examined using a three-dimensional primitive equation model (POM). Case studies using numerical experiments in a small coastal bay in the southern sea of Korea (Hanam Bay) have examined the 'critical depth' (CD) that stabilizes the numerical calculations. Dependence of the CD of typhoon tracks and tidal components such as M2, S2, O1, and K1 were examined. The model results clearly demonstrated that the numerically unstable state of the calculation was caused by the coarse resolution of sea surface elevation.

• Journal of Environmental Science International
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• v.21 no.10
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• pp.1275-1286
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• 2012

Coastal marine ecosystem plays important role of spawning and nursery grounds for fisheries resources. Yongil Bay is one of major coastal marine ecosystems, which is located in the southwestern East Sea of Korea. Species composition and abundance of marine organism in the Yongil Bay were investigated by season from March to November 2009. Gill net and pot fisheries were used for survey of pelagic and demersal species composition, and collected 106 species, 67 families, and 7 taxa of fisheries resources from the coastal ecosystem. Species were included 2 species in Ascidiacea, 2 species in Bivalvia, 6 in Cephalopoda, 22 in Crustacea, 5 in Echinodermata, 12 in Gastropoda, and 57 in Pisces. Diversity indices (Shannon index, H') showed seasonal variation with low value of 2.11 in winter, and high value of 2.63 in autumn. Main dominant species were Asterias amurensis, Pleuronectes yokohamae, Siphonalia spadicea fuscolineata, Trachurus japonicas, Sillago japonica, Conger myriaster, Volutharpa ampullaceal, Engraulis japonicus, Asterina pectinifera, and Portunus (Portunus) sanguinolentus that were occupied over 71.5% of total individuals, and 52.9% of wet weight. Seasonal variations of fisheries resources composition were discussed on correlationships with those of environmental factors in the coastal ecosystem of the Yongil Bay in Korea. Those results from this study will provide scientific data and information to develop the ecosystem-based coastal fisheries assessment and management system in Korea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.1
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• pp.1-10
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• 2000

A three-dimensional hydrodynamic-ecosystem model was developed and applied to Chinhae Bay which is located in the southeastern sea of Korea. The model includes a three-dimensional hydrodynamic model and an eutrophication model, and the model operates on the same grid system. The agreement between predicted and measured results is reasonably encouraging. The concentrations of the calculated COD, DIN and DIP are appeared to be very high due to the phytoplankton production and the wastewater input in the northern part of Chinhae Bay. Anoxic and hypoxic water masses in the bottom layer occur in the northern part of the bay due to the excess loading of wastewater and strong stratification, and in the western inner part of the bay due to high oxygen consumption in densely populated aquaculturing facilities. DO concentration contours show parallel to the bay entrance line, which means the importance of supplying DO by physical process from the mouth of the bay. Although both the hydrodynamic and biochemical processes play important role to form the hypoxic waters in the bottom of the inner bay, it is suggested that the hydrodynamic conditions such as the vertical and the horizontal eddy diffusivity are primarily important factors.

• Journal of Ocean Engineering and Technology
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• v.34 no.6
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• pp.436-441
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• 2020

Wave field changes resulting from artificial coastal structures constructed in coastal zones have emerged as a major cause of beach erosion, among other factors. The rates of erosion along the eastern coast of Korea have varied mainly owing to the construction of various ports and coastal structures; however, impact assessments of these structures on beach erosion have not been appropriately conducted. Thus, in this study, a methodology to assess the impact of erosion owing to the construction of artificial structures has been proposed, for which a parabolic bay shape equation is used in determining the shoreline angle deformation caused by the structures. Assuming that the conditions of sediment or waves have similar values in most coastal areas, a primary variable impacting coastal sediment transport is the deformation of an equilibrium shoreline relative to the existing beach. Therefore, the angle rotation deforming the equilibrium of a shoreline can be the criterion for evaluating beach erosion incurred through the construction of artificial structures. The evaluation criteria are classified into three levels: safety, caution, and danger. If the angle rotation of the equilibrium shoreline is 0.1° or less, the beach distance was considered to be safe in the present study; however, if this angle is 0.35° or higher, the beach distance is considered to be in a state of danger. Furthermore, in this study, the distance affected by beach erosion is calculated in areas of the eastern coast where artificial structures, mainly including ports and power plants, were constructed; thereafter, an impact assessment of the beach erosion around these areas was conducted. Using a proposed methodology, Gungchon Port was evaluated with caution, whereas Donghae Port, Sokcho Port, and Samcheok LNG were evaluated as being in a state of danger.

• Journal of Environmental Science International
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• v.13 no.11
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• pp.993-1000
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• 2004

As an effort to clarify the ecosystem of Osaka Bay, a semi-enclosed coastal area under the influence of stratification, a three-dimensional water quality model with combination of the baroclinic flow model and primitive eco-system model was constructed. The proposed model succeeded in simulating the time-depending flow and density structure and the baroclinic residual currents in Osaka Bay. In present study, we tried to improve the model by taking account of the benthic-pelagic interaction and exchange of nutrients between sea bottom sediments and overlaying water. On vertical structure, the model consists of 13 layers of water and eight layers of sediments. Long-term prediction of water quality was conducted from 1964 to 1985. This period is characterized by rapid water pollution and its decrease by the cutoff reduction of COD and P flowed into Osaka Bay. By combining the sediment model into original model, the numerical model was confirmed to shows more reasonable results in simulating the water quality in Osaka Bay.

• Journal of Korea Port Economic Association
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• v.31 no.3
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• pp.121-140
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• 2015

The present study examines how to construct a transport system for tourism in the marine city area of Yeosu. An effective tourism transport system is needed in Yeosu to promote ocean tourism in Korea's southern coastal region. The problems in Yeosu's transport system for ocean tourism were identified by comparing it with the Bay Area in the United States; future improvement methods were deduced accordingly. The transport support system for ocean tourism in Yeosu area was insufficient in many aspects compared with the Bay Area, such as intercity transportation, urban transport systems, and transport information systems. Thus, this study suggests various approaches to building a new ocean tourism transport support system in Yeosu. Connecting transport modes and ocean tourism resources, such as linking intercity and urban transport modes with ocean tourism transport modes, is suggested. It is also recommended that a cooperative transport support system be established for ocean tourism in the neighboring regions of Yeosu. Furthermore, an integrated transport information system for ocean tourism needs to be provided to connect the system efficiently with ocean tourists. This integrated transport support system could lead to a decrease in the cost and time needed for travel.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.6
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• pp.353-360
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• 2010

The Kyunggi Bay in mid-west of Korea is a relatively large estuarine system that connects the Han River system with Yellow Sea. Due to macro-tidal range of more than 8 m, the urban estuary shows deep tidal channels and wide tidal flats. Since last 30 years, the coastal development is undergoing, yielding noticeable change in environment. Particularly the tidal flat dynamics are generally accepted as being related with tidal residual flows in this area (Kim et al., 2009). We have estimated the annual variation and vertical structure of residual currents with one-year long observed flows in two major tidal channels of Kyunggi Bay. The moving average method and tidal current harmonic analysis yield nearly the same results on residual flow. The residual flow in Jangbong channel ranges from 20 cm/s in summer to 30 cm/s in winter. It is noticeable that the residual flow in Jangbong channel is flood dominant throughout the year, while the flow in Seokmo channel is ebb-dominant residual flow with current speed range of 20-40 cm/s. Due to the baroclinic response of relatively shallow estuary, significant reduction of energy in bottom layers have been observed, indicating the importance of residual circulation to the tidal flat behavior.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.151-156
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• 2003

Spatio-temporal distribution of dinoflagellate cysts was monthly investigated at 6 stations in Gamak Bay, the southern Korea from April 2000 to April 2001. A total of 37 species of dinoflagellate cysts belonging to 22 genera were identified. The temporal changes of species number fluctuated with an annual mean of 8 species, 1 species at Stn. 6 in July in the middle Gamak Bay and 17 species at Stn. 2 in June southern Gamak Bay, but 11 to 20 species occurred in the northwestern Gamak Bay all the year round. The major species were Brigantedinium cariacoense, Brigantedinium simpler, Brigantedinium spp., Protoperidinium americanum, Quinquecusphix concretum, Selenopemphix quanta, Scrippsiella trochoidea, Spiniferites bulloideus, Spiniferites spp., Stelladinium reidii, Votadinium carvum, and Polykrikos sp. of kofoidii. The dominant species of dinoflagellate cysts was not evident in the over-all study areas, but in the northwestern Gamak Bay Brigantedinium spp. and Protoperidinium americanum were dominant $(50.4-76.0\%)$ during the study periods. Abundance of dinoflagellate cysts on the surface sediment in the Gamak Bay ranged from 21 cysts/g dry at Stn. 6 in July to 4,322 cysts/g dry at Stn. 4 in August with an annual mean of 688 cysts/g dry. Especially, the highest value occurred in the northwestern Gamak Bay. Heterotrophic species was more abundant than autotrophic species on the surface sediment. In particular, the former occurred in $75-94\%$ in the northwestern Gamak Bay throughout the year. The northwestern area was very different from other area in species number, dominant species and abundance of dinoflagellate cysts. It is mainly due to water stagnation and eutrophication in the area. And the seasonal abundance of dinoflagellate cysts in Gamak Bay was inversly related to water temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.671-681
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• 2014

The distribution and abundance of coastal fish species in Asan Bay, Korea, were estimated from hydroacoustic survey and net catches. Acoustic data were collected with 38 and 200 kHz from July to October of 2012, and converted to the nautical area scattering coefficient (NASC, $m^2/mile^2$) for $0.25n{\cdot}mile$ along ten transects. Japanese anchovy Engraulis japonicus was the dominant specie in the net catches. The virtual echogram technique was used to distinguish E. japonicus from other species based on the differences in the mean volume backscattering strength (${\Delta}MVBS$) at 38 and 200 kHz. Engraulis japonicus and other fishes are mainly distributed in the center channel and outer part of Asan Bay. E. japonicus tends to move from inner to outer Asan Bay in summer and fall. From NASC data, the target strength and length-weight function of E. japonicus and other fishes were used to estimate the E. japonicus stock at 24.1-93.3 tons, and other fish at 40.6-88.4 tons from July to October 2012. The estimated anchovy biomass compared well with the cumulative catch weight from stow net catches. The hydroacoustic method offers an approach to understanding spatial/temporal structure and estimating the biomass of fish aggregations in coastal areas.