• Journal of the Korean Society for Marine Environment & Energy
• /
• v.6 no.4
• /
• pp.37-44
• /
• 2003

In order to evaluate the contribution of MMSTP operation to the improvement of marine water quality of Mokpo harbour and to estimate the change of pollution loads flowing into Mokpo harbour after the operation of Mokpo Municipal Sewage Treatment Plant (MMSTP), the pollution loads flowing into Mokpo harbour from land in dry weather were surveyed and estimated on the bases of the seasonal flow rates and the seasonal water qualities of streams and effluents located around Mokpo harbour from summer, 1997 to spring, 1998 before the operation of MMSTP, and the pollution loads of the inflow and the effluent of MMSTP were also surveyed and estimated from winter, 1998 to spring, 1999 after the operation of MMSTP. The treatment rates of MMSTP were shown to be about 49% in COD, 76% in TSS, 79% in VSS, 3% in T-N, 7% in DIP, 29% In T-P and -32% in DIN. The change rates of pollution loads flowing into the inner harbour of Mokpo due to the operation of MMSTP were shown to be about 56% in COD, 78% in TSS, 84% in VSS, 45% in DIN, 22% in T-N, 34% in T-P and -14% in DIP The contribution rates of MMSTP operation to the reduction of total pollution loads flowing into the entire Mokpo harbour were found to be about 3% in COD, 3% in TSS, 5% in VSS, 1% in DIP, 3% in T-P and -1% in DIN.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.8
• /
• pp.579-592
• /
• 2020

This study was designed to assess the water quality and phytoplankton community including chlorophyll a in blood cockle (Tegillarca granosa) farms in May, August and November of 2017 in the northwestern Yeoja Bay, Korea. As a result, the seasonal characteristics of water types by water temperature and salinity were clear. Nutrients were abundant in silicate throughout the season, but phosphate was scarce in spring and summer, and nitrogen sources were scarce in autumn. The species composition of phytoplankton community was a very simple distribution, and the standing crop was also very low. The annual dominant species is dominated by the diatoms, with Skeletonema costatum-ls, Nitzschia longissima in spring, Pleurrosigma normanii, Coscinodiscus gigas in summer, and N. longissima, Pseudonitschia pungens, Chaetoceros curvisetus, Eucampia zodiacus in autumn. In summer the results were different from other coastal waters of Korea. The principal component analysis(PCA) and correlation analysis showed that the characteristics of water quality and biological environments differed according to the season. Furthermore, it was determined by the supply of materials through fresh water on land, seawater congestion caused by the refueling of surface sediments with lower depth, and the balance of biological production and mineralization of organic matters in blood cockle farms.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.9 no.2
• /
• pp.86-96
• /
• 1997

In order to investigate the formation of a shallow water front and its relation to water quality distributions, oceanographic measurements were made, and the numerical computations of the Simpson-Hunter stratification parameter log(H/U$^3$) were performed. It is shown from satellite image and hydrographic data that the shallow water front is formed near the northern Kaduk channel, and the stratification parameter log(H/U$^3$) near the front is in a range of 2.0-2.5. Measured COD (Chemical Oxygen Demand) concentrations in offshore region of the front and in the western part of the bay are below 2.0 mg/1. whereas the concentrations in Masan Bay located in the northern inside of the frontal zone are high as 3.0-5.5 mg/1. COD concentrations decrease gradually from Masan Bay toward the offshore due to the dilution by strong water mixing. Anoxic and hypoxic water masses at the bottom layer in summcr occur in the western part of Chinhae Bay and in Masan Bay, and DO (Dissolved Oxygen) concentrations become low with increasing the stratification parameter. DO concentrations outside the front are more than about 4.0 mg/1, whereas the concentrations inside the front are low. The shallow water front plays a significant role for material transport from coastal area to oceanic area, and the frontal region seems to be important physical and chemical boundaries.

• Journal of Fisheries and Marine Sciences Education
• /
• v.24 no.4
• /
• pp.507-515
• /
• 2012

Jungmun beach was confirmed only one beach as a nesting place of seaturtles in Jeju of South Korea. We investigated the environment conditions for nesting of seaturtles (sites 1, 2) to target as the spawning grounds of accidental nesting place. Sand temperatures of beaches at 5 cm above and 10, 30 and 50 cm below the surface of beach were measured at intervals of approximately 10 days during June to December. These data indicated that the optimum (over $25^{\circ}C$) sand temperature for spawning and hatching of seaturtles in the sites 1 and 2 from June 23 to September 29, 2008 and from June 23 to October 17, 2008, respectively. Also, maintained the optimum coastal water temperature (above $20^{\circ}C$) for seaturtles maintained from June 23 to November 17, 2008. Therefore, Jungmun beach could be the possible spawning grounds of accidental nesting place, where the landed seaturtles and hatched young seaturtles could be survived successfully.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.6
• /
• pp.562-575
• /
• 2023

In an effort to improve water quality, the South Korean government has implemented measures to increase seawater circulation in Saemangeum Lake. We analyzed the effect of increasing the frequency of seawater circulation based on salinity levels and bottom water exchange in the lake, using an environmental fluid dynamics code model. When the sluice gate opening and shutting frequency increased from once to twice per day, the internal water level of Saemangeum Lake increased by up to ~0.7 m. The salinity increased by 2.12 psu near the western breakwater and decreased by 1.18 psu near the freshwater inlet. We analyzed the extent of bottom water exchange using a particle tracing method and observed that the residual rate of particles shallower than 5 m in water depth decreased by 2.52% in Case 2 (opening and shutting twice per day) compared to Case 1 (opening and shutting once per day). This indicates that increasing the frequency of sluice gate opening and shutting would promote enhanced bottom water exchange. Consequently, the increased salinity and bottom water exchange associated with increased seawater circulation are expected to improve water quality in Saemangeum Lake.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.11 no.2
• /
• pp.82-91
• /
• 2006

We investigated the possibility of using effluents from a municipal sewage treatment plant (STP) as tracers a tracer for hydrologic studies of rivers. The possibility was checked in a 12-km long reach downstream of Jeonju Municipal Sewage Treatment Plant (JSTP). Time-series monitoring of the water chemistry reveals that chemical compositions of the effluent from the JSTP are fluctuating within a relatively wide range during the sampling period. In addition, the signals from the plant were observed at the downstream stations consecutively with increasing time lags, especially in concentrations of the conservative chemical parameters (concentrations f3r chloride and sulfate, total concentration of major cations, and electric conductivity). Based on this observation, we could estimate the stream flow (Q), velocity (v), and dispersion coefficient (D). A 1-D nonreactive solute-transport model with automated optimization schemes was used for this study. The values of Q, v, and D estimated from this study varied from 6.4 to $9.0m^3/sec$ (at the downstream end of the reach), from 0.06 to 0.10 m/sec, and from 0.7 to $6.4m^2/sec$, respectively. The results show that the effluent from a large-scaled municipal STP frequently provides good, multiple natural tracers far hydrologic studies.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.16 no.4
• /
• pp.196-205
• /
• 2004

Water qualities (WQ) were measured biweekly from April 2nd to October 29th, 2003 in Sillicheon flowing into the entrance of Jumunjin Harbour and daily water quantities (river discharges) were estimated by the TANK model which has been widely used to compute the runoff discharges in the ungauged watersheds. The spatial and temporal change patterns of the measured WQs were analysed in detail and the correlation between rainfall - WQ and river discharge - WQ were also analysed. From this results, it is found that the correlation coefficient between BOD concentration and rainfall is 0.75 and between the SS concentration and 2-days river discharge is 0.36. The correlation between the COD, TN, TP in the station of Silli Lower Bridge and rainfall runoff quantity was analysed as un-correlated items. As a consequence, the estimated BOD and SS pollutants loads are reliable and show good change patterns even though the accuracy of SS pollutants load is slightly low. The estimated COD, TN and TP pollutants loads, however, can be used only as the reference or averaged values. In order to analyse more accurately the temporal change patterns of these items, more-detailed researches considering the artificial effects and landuse patterns are highly required.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.15 no.4
• /
• pp.297-313
• /
• 2009

Long-term trends and distribution patterns of water quality were investigated in the Gunsan coastal areas of Yellow Sea, Korea from 1972 to 2006. Water samples were collected at 6 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids(SS), chemical oxygen demand(COD), dissolved oxygen(DO) and nutrients. Spatial distribution patterns of temperature, DO and SS were not clear among stations but the seasonal variations were distinct except COD and SS. The trend analysis by principal component analysis(PCA) during 24 years revealed the significant variations in water quality in the study area. Spatial water qualities were clearly classified into 3 clusters by PCA; station cluster 1, 2~4, and 5~6. Annual water qualities were clearly classified into 4 surface water clusters and 5 bottom water clusters by PCA. By this multi-variate analysis. The annual trends were summarized as follows; Salinity, pH and DO tended to increase since late 1970's, COD to increase since 1987, and SS to decrease and nutrients to increase in Gunsan coastal waters due to the input of fresh water from land same as in Kyoungin coastal area, Asan coastal area and Choensoo bay.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.30 no.5
• /
• pp.201-206
• /
• 2018

This study investigated the changes in pore water quality of polluted sediment by mixing ratio of granulated coal ash. The mesocosm experiments were carried out with 0%, 10%, 30% and 50%, respectively, of the material mixture ratio relative to the sediments. According to the results of the experiments, pH increased depending on the mixing ratio. Phosphate and ammonia concentrations were significantly decreased in the mixing ratio of 30% and 50% compared to the control (p < 0.05). The concentration of hydrogen sulfide was reduced by 72% at the mixing ratio of 10%, and it was not detected at the mixing ratio of 30% and 50%. This study was confirmed that granulated coal ash can change the pore water quality of polluted sediments in proportion to the amount of material. However, the effect of the mixing ratio between 30% and 50% was not significantly different, thus it is concluded that mixing of 30% of the volume of the sediment is economically feasible.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.14 no.1
• /
• pp.1-10
• /
• 2011

To understand characteristics of the water quality on the coastal boundary on tidal flat, field observations between 2008 and 2009 were undertaken twice a month at five coastal areas (Muan bay, Tando bay, Hampyeong bay, Shinan Jido and Yeongkwang coastal areas). Yearly water temperature difference was large with the range between $1.3^{\circ}C$ and $31.1^{\circ}C$. Salinity was about 32 but was the lower less than 20 for the heavy rainfall season. DO was high in winter and low in summer according to the variation of water temperature. pH represented the variation similar to DO. Suspended solid was averagely high over 100 mg/l in Yeongkwang coastal area, especially. COD did not revealed large variation with the value of about 1 mg/l. DIN and DIP concentration were high when freshwater was highly input in summer. DIN concentration was low for winter and early spring but DIP concentration did not show the seasonal variation with the continuous increase from July 2009 to December 2009. Chlorophyll a appeared high for spring with approximately $10\;{\mu}g/l$ and was higher for summer in Yeongkwang coastal area than other sites. The results of principal component analysis conducted to compare the characteristics of water quality observed in study areas showed the distinguishable features as follows. The freshwater input fluctuation appeared as the first factor in Muan and Tando bays, and the change of water temperature was the first factor in Shinan Jido and Yeongkwang coastal areas. The influence mixed with the variation of freshwater outflow and the change of water temperature in Hampyeong bay was to be the first factor.