• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.759-762
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• 2008

A wastewater treatment plant located in coastal areas should be built considering the discharge of rainwater and treated water into the sea. The current Hagik Wastewater Treatment Plant in Incheon City was designed in the surface discharge method, which refers to discharging treated water directly into the sea. This method may cause hydrodynamic issues in a wastewater treatment plant because seawater enters an outfall riser when the level of discharged water is lower than the tidal level on a shore with high tidal range. In this study, a method for installing a weir in the discharge manhole was proposed in order to prevent seawater from entering the outfall riser of a wastewater treatment plant. Its feasibility was reviewed by calculating the hydrodynamic that had occurred due to the installation of the weir. As a result, seawater did not enter in the discharge manhole. Thus, even if the coast of Incheon City reaches the highest tidal level, treated water will be able to be properly discharged.

• Journal of Ocean Engineering and Technology
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• v.14 no.3
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• pp.11-19
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• 2000

This study aims to examine the characteristics of the water quality variation in relation to the change of water exchange rate with respect to the development phases of the Pusan port. To clarify the characteristics, water exchange caused by the variations of coastline shape and water surface area was examined by the numerical experiments using the Lagrangian particle tracking model based on 2-D shallow water equation. As the results of numerical experiments, it was proved that the water exchange in the Pusan port was decreased mainly due to the port development and the breakwaters construction. During the port development phases from 1875 to 1998, 35% of the sea-space in the port had decreased to make hinterland spaces. This resulted in the loss of wet-land and coastline change as well as decrease of the water exchange rate at the sea side. The city population in that period had rapidly increased from several thousands to 4 millions, resulting in the large discharge of sewages into the port area. Under the these environmental conditions, it can be clearly said that the water quality in the Pusan port is sensitively affected by the discharge of urban sewages decrease of the water exchange rate in relation to port and urban developments. In the study, the temporal changes of water quality were discussed with respect to the port development phases. It was clear that the water quality wad controlled by the exchange rate change under the port development as well as the input impact into the port from the urbanized city area. To make clean sea of the Pusan port, it is suggested that the sewage control, the water exchange and coastline control should be systematically checked under the concept of eco-friendly development and environmental management.

• Proceedings of the KSRS Conference
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• v.1
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• pp.118-121
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• 2006

Variations in the extent and dispersal of river plume are important in the study of coastal environment. The objectives of this study are to examine relationship between satellite detected plume area and river discharge and to clarify the temporal and spatial dynamic of plume from Tokachi River, Hokaido, Japan. We used 1.1 km spatial resolution of SeaWiFS normalized water-leaving radiance (nLw) images from 1998 to 2002. Supervised maximum likelihood classification was implemented to define classes of surface water optical properties. Satellite observed plume area was correlated to the amount of river discharge from April to October. First mode (44% of variance) of EOF analysis shows the turbid plume distribution resulting from re-suspension by strong wind mixing along the coast during winter. This mode also shows plume distribution along-shelf direction in spring and late summer. Second mode (17% of variance) shows spring pattern across-shelf direction due to strong discharge of snow melting water.

• The KSFM Journal of Fluid Machinery
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• v.16 no.5
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• pp.11-17
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• 2013

This study is aimed to construct a marine small hydro power plant using discharge water of fish farm in Jeju Haengwon-ri. The difference of design methods between marine small hydro power plant and land small hydro power plant is to consider the tides. Moreover, ground condition should be examined because gushout sea water comes out from the ground at high tide in Jeju as the ground of Jeju beach consists of basalt stone. From the field test of the turbine generator after construction of the power plant, output power and efficiency of the turbine generator shows good conformance to the required conditions.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.4
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• pp.453-462
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• 2011

This study was analyzed to determine the cause of red tide at 10 and 30 days antecedental rainfall, stage and discharge in the Taehwa River, tidal data of Ulsan port, also, it was analyzed variation of red tide population, salinity, BOD, COD, T-N, T-P at S1, S2 each point. Most of the red tide in the Taehwa River occurred by provision of proper nutrients with antecedent, the proximity between discharge and low-flow capacity, and stage and discharge of stabilized condition after the sea water was inflowed by maximum tide difference. Red tide population is not nearly related to the change of salinity, the Taehwa River seems specific features of Non-coastal rivers downstream, because red tide was occurred when salinity quite low-end condition.

• Proceedings of KOSOMES biannual meeting
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• 2009.06a
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• pp.89-94
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• 2009

This study aims to examine the the characteristics if the sea water circulation in related to the change of the water exchange rate according to the the development phases of Busan Port. To clarify the characteristics, the water exchange caused by construction if new-port and river discharge conditions was examined by the numerical experiments using the Lagrangian particle tracking model based on 2-D shallow water equation. This study deals with the charge of flow field and water exchange after redevelopment using numerical simulation technique, based on the field observation and 4 rivers discharge flow. As a result if numerical simulation, Variation if current velocity in Busan North Port is almost nothing before and after construction. Water exchange of channel in area of redevelopment is a little. Futhermore, the tidal exchange had a tendency to be small both before and after redevelopment by 60%.

• Ocean and Polar Research
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• v.29 no.2
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• pp.135-153
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• 2007

Temporal (seasonal) and spatial distributions and variations of various physico-chemical factors (salinity, temperature, pH, DO, COD, SPM, POC, silicate, DIP, DIN) in surface and bottom waters were studied in the coastal environment with typical macro-tidal range and monsoonal weather condition, Gyeonggi Bay, west coast of Korea. Spacial distribution patterns of these factors were generally similar to each other, and appeared to be inversely related to the distribution pattern of salinity, suggesting that water quality of the study area was primarily controlled by the physical mixing process of Han-River freshwater with nearby coastal seawater. During flooding season, silicate- and nitrogen-rich Han River water directly flowed into offshore as far as $20\sim30\;km$ from the river mouth, probably causing serious environmental problems such as eutrophication and unusual and/or noxious algal bloom, etc. Except the surface water during summer flooding season, high concentrations of nutrients appeared generally in dry season, whereas low values in spring, possibly because of the occurrence of spring phytoplankton bloom. On the other hand, nutrient flux through the estuary seems to be primarily depending on river discharge, sewage discharge and agricultural activities, especially during the rainy season. Also, nutrients in this coastal waters are considered to be supplied from the sediments of tidal-flats, which developed extensively around the Han-River mouth, especially during fall and winter of dry and low discharge seasons, possibly due to the stirring of tidal flat sediments with highly enriched pore-water nutrients by storm. And also, COD and DIN concentrations in the study area consistently increased during the last 20 years, probably because of agricultural activities and increasing discharge of industrial and domestic wastes.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.4
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• pp.219-235
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• 2013

In order to investigate the changes in sea water characteristics and stratification due to operation of Shihwa tidal power plant, three dimensional numerical model is used. In summer, the density of inner part of Shihwa Lake is more affected by salinity than water temperature due to fresh water discharge. Before tidal power plant operation, the sea water characteristics in Shihwa Lake shows relatively high temperature and low salinity. After tidal power plant operation, water temperature decreases slightly and salinity tends to increase in Shihwa Lake. Also, density increases and stratification tends to weaken by mixing with sea water.

• Journal of Environmental Science International
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• v.15 no.11
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• pp.1017-1025
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• 2006

This study was conducted to evaluate characteristic of water duality in coastal sea of Incheon using a multivariate analysis. The analysis data in coastal sea of Incheon was aquired by the NFRDI data which was surveyed from March 1997 to November 2003. Eleven water quality parameters were determined on each survey The results were summarized as follow : Water quality in Incheon coastal sea could be explained up to 64.62% by three factors which were included in loading of fresh water and nutrients by the land(36.98%), seasonal variation(16.19%), and internal metabolism (11.24%). The results of time series analysis by factor score, in case of factor 1, station 1 influenced by Han river was shown to high factor score and station 3 located by outer sea was shown to low factor score. In case of factor 2, station 1 was appeared to high variation and station 3 was appeared to low variation. The result of cluster analysis by station was classified into three group that has different water quality characteristics. Especially, station 1 which affected by Han river and station 4 which affected by sewage treatment plant was appeared to considerable water quality characteristics against other station. In yearly cluster analysis, three group was classified and water quality in 2003 years due to high precipitation was different to another year. It could be suggested from these results that it is important to control discharge of fresh water by Han rivet and sewage treatment plant for water quality management of coastal sea of Incheon.

• Ocean and Polar Research
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• v.31 no.2
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• pp.177-187
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• 2009

This study examined the multi-scale variabilities of sea surface temperature (SST) and salinity in the Japan/East Sea (JES) based on statistical analyses of observational data, with a focus on the northwestern part of the sea. The regionality of JES SST variability was estimated for different frequency ranges on semimonthly (11-17 days), monthly to seasonal (30-90 days), quasi-semiannual (157-220 days), and quasi-biennial (1.5-3 years) time scales using cluster analyses of daily gridded SST data for 1996 to 2007 from the Japan Meteorological Agency (JMA). Several significant peaks and regional cores were found in each frequency range of the SST anomaly (SSTA) oscillations. Quasi-semiannual SSTA oscillations with high amplitude were found in the south-southwestern part of the Japan Basin ($41-43^{\circ}N$) and were amplified in the area adjacent to Peter the Great Bay. Oscillations with periods of 79 and 55 days also prevailed over the southwest Japan Basin between the Yamato Rise and the continental slope. A similar method was applied to classify SST and the annual cycle of surface salinity using Generalized Digital Environmental Model (GDEM) gridded data. The Tatarskii Strait and adjacent area showed the most specific annual cycles and variability in salinity on interannual to interdecadal time scales. The most significant inverse relationship between surface salinity in the Tatarskii Strait and southern JES areas was found on the interdecadal time scale. Linkages of sea water salinity in the Tatarskii Strait with Amur River discharge and wind velocity over Amurskii Liman were also revealed.