• Journal of Environmental Impact Assessment
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• v.16 no.6
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• pp.421-432
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• 2007

To investigate temporal and spatial variations of hydrodynamics and environmental conditions in Gyeonggi Bay, including Han River estuary, numerical experiments were performed using 3-dimensional fine grid numerical ocean model. The model successfully reproduced the physical phenomena already known in Gyeonggi Bay where tide and fresh water discharge are dominant forcings. The calculated harmonic constants of tide and tidal current agreed well with those of observations at nine tide stations and two tidal current stations. Tidal asymmetries along the Yeomha Waterway, mainly caused by non-linear effect, were well reproduced and agreed well with observations. Time series of salinity at four stations(A, B, C and D) and horizontal distributions of monthly averaged salinity show that Gyodong and Seokmo Waterways play an important role in fresh water discharge into the Gyeonggi Bay rather than Yeomha Waterway.

• Ocean and Polar Research
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• v.25 no.4
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• pp.593-601
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• 2003

The purpose of this paper is to investigate economic feasibility of creating artificial tidal flats using cost-benefit analyses. We assumed that the cost factors are associated with designing, construction and monitoring, and the benefit factors are associated with fisheries production, habitation, prevention of disasters, water purification, aesthetic value and existence value. First, for analyzing economic feasibility, the scenario suggests that a design can be made in a year, construction can be completed in three years and monitoring must be made for 20 years. Assuming the discount rate of 7.5%, economic feasibility analyses showed that B/C was 2.26 and IRR was 14.50. This study indicated there is economic validity of implementing creation of artificial tidal flat. In addition, we carried out a sensitivity analysis at the change of discount rate and restoration rate. The result of sensitivity analysis clearly showed that economic validity is low when discount rate is over 15%, and changes in restoration rate did not significantly effect on the economic validity.

• PNF and Movement
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• v.12 no.3
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• pp.181-188
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• 2014

Purpose: The purpose of this current study is to compare the effectiveness of respiratory circulation function and tidal volume according to two different types of practice methods, in terms of breathing training program and abdominis muscle strengthening using a swiss ball. Methods: The subjects were consist 18 college students, were randomly and evenly assigned to either breathing training program group (BTG) or swiss-ball exercise group (SEG). Exercise program was applied for 60 minutes, 3 times a week, for 6 weeks. Before, after 3 weeks and after 6 weeks of exercises, the subjects were tested using the bruce protocol. The significance of differences between the BTG and the SEG was evaluated by analysis of two-way repeated measures ANOVA. Results: There was an increase in respiratory circulation function after both of exercise. Especially, there was significant difference between the before and after 6 weeks in the BTG. Also, change of respiratory circulation function in BTG was significantly greater than SEG. Tidal volume was no significant differences between the before and after 6 weeks in both groups. In addition, there was significant difference between BTG and SEG. Conclusion: These results suggest that direct breathing training program were more useful to improve of respiratory circulation function.

• Journal of Ocean Engineering and Technology
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• v.23 no.2
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• pp.18-27
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• 2009

This study was conducted to examine the effect of wind on the circulation of seawater in Gamak Bay, which contains numerous farms for fish and shellfish but suffers a significant loss by fisheries nearly annually from harmful algal blooms. In numerical experiments with a simplified bathymetry for Gamak Bay, the wind in summer appeared to more strongly influence the east-westward flow than the south-northward flow. In winter, this trend was nearly similar to the summer but seemed to have a greater effect on the flow at the north-west of the bay than the flow at the south mouth of the bay. On the other hand, in numerical experiments with a realistic bathymetry for Gamak Bay, the wind in summer appeared to more strongly influence the east-westward flow than the south-northward flow. Furthermore, the effect of the wind was stronger at the south mouth of the bay than at the north-west of the bay. In contrast, the wind in winter affected the east-westward flow more strongly and its effect appeared stronger at the north-west of the bay than at the south mouth of the bay. In addition, the effect of the wind tended to increase with distance from the east to the west. Therefore, the tidal currents in Gamak Bay proved to be strongly influenced by the wind, in particular east-westward. However, some measures are urgently required to improve the water quality of the bay, since the south-northward flow turned out to be obstructed by an east-westward shoal located in the middle of the bay.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.41-51
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• 2013

The tidal creek dependent mass transport characteristic in Gyeong-Gi Bay (west coast of Korea) was studied using field measured data and numerical model. Gyeong-Gi Bay consists of 3 main tidal channels and contains a well-developed vast tidal flat. This region is famous for its large tidal difference and strong current. We aim to study the effect of tidal creek in the tidal flat on the mass exchange between the estuary and the ocean. For numerical application, the application of unstructured grid feature is essential, since the tidal creek has complicated shape and form. For this purpose, the FVCOM is applied to the study area and simulation is performed for 2 different cases. In case A, geographic characteristics of the tidal creek is ignored in the numerical grid and in case B, the tidal creek are constructed using unstructured grid. And these 2 cases are compared with the field measured cross-channel mass transport data. The cross-channel mass transport at the Yeomha waterway mouth and Incheon harbor was measured in June, 9~10 (Spring tide) and 17~18 (Neap tide), 2009. CTD casting and ADCP cross-channel transect was conducted 13 times in one tidal cycle. The observation data analysis results showed that mass transport has characteristic of the ebb dominance Line 1 (Yeomha waterway mouth), on the other hand, a flood dominant characteristic is shown in Line 2 (Incheon harbor front). By comparing the numerical model (case A & B) with observation data, we found that the case B results show much better agreement with measurement data than case A. It is showed that the geographic feature of tidal creek should be considered in grid design of numerical model in order to understand the mass transport characteristics over large tidal flat area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.1
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• pp.27-34
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• 2001

To investigate the processes governing the distribution of elements in the tidal flat, thirty-eight sediment samples collected from the Saemangeum tidal flat of the Korean west coast were analyzed for their contents of major (Al, Fe, Mg, Ca, Na, K, Ti) and trace (P, Mn, Ba, Sr, V, Cr, Co, Cu, Ni, Zn, Pb) elements. Most elements showed generally lower contents compared to data published for other tidal flats of Korea, and the effect of anthropogenic input could not be recognized in the sediments. The relative abundance and distribution of most of the elements varied significantly with the grain size of sediments. High contents of Al, Fe, Mg, Ti, P, Mn, V, Co, Cr, Cu, Ni and Zn were found in the finer sediments in the upper tidal flat of the study area, suggesting that tidal sedimentation processes play an important role in controlling the distribution of these elements. However, sediment grain size does not impose any significant effect on the abundance and distribution of Ca, Na, K, Ba, Sr and Pb. It appears that the clastic mineralogy in the coarse-grained fractions is the dominant factor determining the distribution of these elements in the study area.

• Journal of Korea Water Resources Association
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• v.38 no.2
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• pp.121-131
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• 2005

In this study, a flood routing model is used for analyzing change of flood stage induced by various factors. The results by using the past cross section measurement data showed the minimum error in case of accurate measurement of cross section as well as reasonable boundary condition of model. In analyzing the rise of flood stage of main stream considering Inflow magnitude of tributary, it showed that the larger the flow magnitude is, the smaller the variance of stage is. The results of analysis in the tidal effect at Wolgot are that the tidal effect influence the stage profile into upstream in case of normal discharge of main stream and tributary but doesn't influence it even with maximum flood tide in case of project flood. Finally, when the various hydraulic factors are considered in numerical analysis, more systematic and realistic flood forecast system is able to be performed.

• Journal of Environmental Science International
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• v.7 no.2
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• pp.223-232
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• 1998

The spatial characteristics of stratification In Deukryang Bay were studded using observed data and analytical models. From the description of the density structure and its the potential energy anomaly (PEA) from observed data along longitudinal direction (from the mouth to head of the bays, we found that the stratification Intensity could be changed strongly by density current effect during the spring-neap tidal cycle, and depth variation. To find out density current effect for the formation of the stratification In detail, we Implemented a diagnostic approach by using the modified analytical model including density current, tidal current, surface heating and wind stirring. The model allowed for the observed similarities for the whole domain in the bay and increased tidal mixing efficiency value s up to 0.006-0.007 as compared to the results without density current effect. We found that the density current effect was also an important key factor In determining the formation of the spatial distribution of stratification.

• The Korean Journal of Malacology
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• v.30 no.2
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• pp.117-126
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• 2014

To assess the effect of environmental factors on the sustainability of cultured production manila clam (Ruditapes philippinarum), we investigated the habitat characteristics of tidal flat (Hwangdo and Jeongsanpo in Taean). We measured the physiochemical parameters (temperature, salanity, pH, dissolved oxygen and nutrients) and the characteristics (mean size, chemical oxygen demand, ignition loss, C/N ratio and C/S ratio) of surface sediments. The C/N ratio of Hwangdo and Jeongsanpo were 9.0, 5.3 and the C/S ratio was 0.162, 0.159. The concentration of chlorophyll a at Hwangdo was higher than that of Jeongsanpo and species of micro algae were 102 and 100. The enrichment factor (Ef) and index of accumulation rate (Igeo) of the metals showed that those research areas can be classified as heavily polluted, heavily to moderately polluted, or more or less unpolluted, respectively. So two survey area of cultured clams in the tidal flat have been effected by the various environmental conditions, there are needed an improvement methods and continuous research for increasing the production of manila clam (Ruditapes philippinarum).

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.3
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• pp.22-35
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• 2011

Incheon Bay has a suitable condition for tidal power generation due to the high tidal range by topographical effect. Therefore a study on the technology development for tidal energy utilization has been promoted since 2006. It is needed to deduce optimal alternatives to determine the suitable location of facilities for tidal power generation and to reduce the environmental damage from development. In order to carry out efficiently this mission, spatial information system is essential to manage and use various spacial elements related to the development and conservation. In this study, for the development of tidal energy, spatial data could be defined as three kinds of dataset. Fundamental dataset is defined as spatial data such as tide, tidal current, wave, erosion and sedimentation. Framework dataset is composed of topographical map, facility map and bathymetry. The reference dataset is composed of marine ecology and environment having the characteristics of thematic map. This study is mainly aimed at establishing methodology of conceptual spatial data modeling classifying as essential data model and optional data model through the definition of the components of spatial data.