• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.44-47
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• 1995

연안 해역에 있어서 해양환경의 변화는 자연적인 요인과 인위적 요인으로 구분할 수 있다. 최근 산업발달과 더불어 진행되어진 연안역에서의 대규모 공사들은 해양환경변화의 인위적 요인으로 작용하여 인근해역에 부유사 및 소류사의 침전과 세굴을 초래하며 해수유동을 변화시켜 장기적인 퇴적환경의 변화를 초래하고 있다. 특히 본 연구의 대상지역인 금강하구역은 지난 십여년 동안 대규모의 공사들이 시행되어 왔으며, 최근 외항 부근에서 집중적인 공사가 진행중이고 금강하구둑의 수문이 ＇94년 8월 31일 부터 패쇄되어 해수유동 및 퇴적환경의 일대 변화가 예상된다. (중략)

• Magazine of the Korean Society of Agricultural Engineers
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• v.36 no.3
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• pp.67-73
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• 1994

This paper is to validate the proposed models for the real-time forecasting for the Keum river estuary dam such as tidal-level forecasting model, one-dimensional unsteady flood routing model, and Kalman filter models. The tidal-level forecasting model was based on semi-range and phase lag of four tidal constituents. The dynamic wave routing model was based on an implicit finite difference solution of the complete one-dimensional St. Venant equations of unsteady flow. The Kalman filter model was composed of a processing equation and adaptive filtering algorithm. The processng equations are second ordpr autoregressive model and autoregressive moving average model. Simulated results of the models were compared with field data and were reviewed.

• Journal of Korea Water Resources Association
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• v.34 no.1
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• pp.19-30
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• 2001

A laterally averaged 2-dimensional hydrodynamic model is newly developed. The coordinate system is first transformed to minimize the effects of irregularity of bottom and surface. The advection terms of the governing equations are then discretized by an upwind scheme. By employing an explicit scheme for longitudinal direction and an implicit scheme for vertical direction, the model is free from restriction of temporal step size caused by a relatively small grid ratio. To demonstrate the applicability of the model, calculated time histories of free surface displacements and distributions of velocity and salinity are compared with the field measurements of the Keum River Estuary before construction of the estuary dam. A reasonable agreement is observed between them.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.3
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• pp.154-163
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• 2005

Irregular discharges of freshwater through the water gates of the Keum River Estuarine Weir, Korea, whose construction had been completed in 1998 with its water gates being operated as late as August 1994, drastically modified the estuarine environment. Sharp decrease of salinity along with the altered concentrations of inorganic nutrients are accompanied with the irregular discharges of freshwater into the estuary under the influence of regular semi-diurnal tidal effect. Field sampling was carried out on the time of high tide at 2 fixed stations(St.1 near the Estuarine Weir and St.2 off Kunsan Ferry Station) every other day for 4 months from mid-February 2004 to investigate into the semi-weekly variation of spring phytoplankton community in relation to the freshwater discharges from Keum River Estuarine Weir. CV(coefficient of variation) of salinity measurements was roughly 2 times greater in St.1 than that in St.2, reflecting extreme salinity variation in St.1 Among inorganic nutrients, concentrations of N-nutrients($NO_3^-,\;NO_2^-$ and $NH_4^+$) were clearly higher in St.1, to imply the more drastic changes of the nutrient concentrations in St.1. than St.2 following the freshwater discharges. As a component of phytoplankton community, diatoms were among the top dominants in terms of species richness as well as biomass. Solitary centric diatom, Cyclotella meneghiniana, and chain-forming centric diatom, Skeletonema costatum, dominated over the phytoplankton community in order for S-6 weeks each (Succession Interval I and II), and the latter succeeded to the former from the time of <$10^{\circ}C$ of water temperature. Cyanobacterial species, Aphanizomenon Posaquae and Phormidium sp., which might be transported into the estuary along with the discharged freshwater, occupied high portion of total biomass during Succession Interval III(mid-April to late-May). During this period, freshwater species exclusively dominated over the phytoplankton community except the low concentrations of the co-occurring 2 estuarine diatoms, Cyclotella meneghiniana and Skeletonema costatum. During the 4th Succession Interval when the water temperature was over $18^{\circ}C$, the diatom, Guinardia delicatula, was predominant for a week with the highest dominance of $75\%$ in discrete samples. To summarize, during all the Succession Intervals other than Succession Interval III characterized by the extreme variation of salinity under cooler water temperature than $18^{\circ}C$, the diatoms were the most important dominants for species succession in spring. If the scale and frequency of the freshwater discharge could have been adjusted properly even during the Succession Interval III, the dominant species would quite possibly be replaced by other estuarine diatom species rather than the two freshwater cyanobacteria, Aphanizomenon flosaquae and Phormidium sp.. The scheme of field sampling every other day for the present study was concluded to be the minimal requirement in order to adequately explore the phytoplankton succession in such estuarine environment as in Keum River Estuary: which is stressed by the unpredictable and unavoidable discharges of freshwater under the regular semi-diurnal tide.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.6
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• pp.70-80
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• 2007

This study was surveyed from January to september, 2007 in order to evaluate the function of coastal wetland as a ecological axis in korea peninsula. Assessment was done by RAM (Rapid Assessment Method). RAM is consisted of total 8 contents and divided into high, moderate, low. The preservation grade of RAM is divided into 4 grades; absolute preservation, preservation, improvement and improvement or restoration. Throughout survey on total 14 wetlands of marine, estuary wetland and back marsh which are distributed in west coast in chung-nam province, their function was assessed. As result, total all the 14 wetlands were judged as preservation grade by assessment of 8 functional contents. The function of wetlands assessed as preservation grade showed high in water quality protection and improvement. Also, showed high in vegetation diversity, wildlife habitat and aesthetic recreation. Meanwhile, showed low in ground water recharge, Shoreline/Stream Bank Protection, Flood/Stormwater storage and Flood flow alteration. Of wetlands evaluated as preservation grade, Dae-ho, Sinduri, Bu-Nam lake, Sowhang dune and keum river estuary were assessed as absolute preservative area owing to habitation of international protection species and endangered species. These wetlands are essential to be managed continuously as a area having high ecological value. Farther, this wetlands will be done as a axis of ecological network related to land ecosystem.

• Journal of Environmental Science International
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• v.9 no.2
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• pp.125-129
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• 2000

As one of the fundamental survey to evaluate purification capacity of pollutants at the tidal flat sediments, we studied vertical environmental characteristics in three tidal flat sediments, Chunjangdae, Eueunri and Gyewhado. These are dissmilar to external feature in each other. The results of this study may be summarized as followed; As the results of particle analysis, Eueunri tidal flat fediment located in Keum river estuary consists of 98.98% as silt & clay, Chunjangdae tidal flat sediment located in SeocheonGun consists of 97.99% as sand. And Gyewhado tidal flat sediment located in Saemankeum in Saemankeum area consists area consists of 32.81% as silt & clay and 67.19% as sand. The concentration of organic pollutants(I.L., COD, POC, PON) in Eueunri tidal flat sediment which highly content of silt & clay were 3~4 times higher than others. The concentration of organic pollutants at each layer were slightly increase goes with deepen layer. The linear correlation between I.L. and COD, POC, PON were obtained. Correlation coefficients were in range of 0.821~0.940. Also the correlation between pH and COD, POC, PON were high(>r=0.9). Filteration rate in Chunjangdae tidal flat sediment was 0.01584cm/s as mean value, but the other were almost nothing filtered off.

• Journal of the Korean earth science society
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• v.22 no.3
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• pp.179-185
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• 2001

Borehole tests are commonly used as a tool to obtain the physical properties of soils and rocks. The results of borehole tests are, however, discontinuous. Interpolation methods are applied to interpret the data gap between the borehole test points. The interpolation is valid only if the horizontal variations of the ground between the test points are small enough to ignore. A surface wave inversion method was used to study the S wave velocity of the very soft soil to provide the continuous 2 dimensional S wave velocity structure. The resolution of the S wave velocity structure was used to interpret the inversion results.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.1 no.1
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• pp.44-49
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• 1989

Cohesive sedimentation mechanism is affected by various physico-chemical factors. Thus, the field observations and the laboratory experiments for cohesive sediment have been reported for decades. Erosion and deposition test was carried out with cohesive sediment material sampled in the Keum River Estuary in this study. The change of the suspended cohesive sediment concentration was measured for various flow conditions, which have the purpose to determine the critical shear stress and the coefficients for erosion and deposition . The critical shear stress and the coefficient for erosion were determined in the flume test. The equilibrium concentration was determined for each shear stress and the relationship between the normalized equilibrium cocentration with the initial cocentration (Ceq/co) and the equivalent shear stress was obtained. The experimental results were compared with the other results and showed fairly well agreements with them.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.247-258
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• 2016

Physical and acoustic properties of sediment on the southwestern Taean Penisula, the Yellow Sea, were studied using eight piston cores. The sediments in the study area are largely composed of sand which has been deposited with sea-level change after LGM(Last Glacial Maximum). After the sea-level rise, fine-grained sediments discharged from Keum River and neighboring coast area were deposited as muddy sand or sandy mud. Results of these sedimentary environment in this area, the texture of sediments are different from place to place with variable horizontal and vertical distribution of physical and acoustic properties. Correlations among the physical, geoacoustic properties, and mean grain size show slight deviations from those of the South Sea in spite of similar pattern. This is probably due to the differences in sedimentary environment, mineral composition, and measurement system.

• The Korean Journal of Quaternary Research
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• v.7 no.1
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• pp.69-91
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• 1993

A total of 76 surface sediment samples, collected from the Korean west coast and the eastern Yellow Sea areas, were analyzed for their elemental composition in order to understand the geochemical characteristics of these deposits. The analyzed elements included 9 major elements (Al, Fe, Na, K, Mg, Ca, Ti, P, Mn), 8 minor elements (Sr, Ba, V, Cr, Co, Ni, Cu, Zn), organic carbon and calcium carbonate. Contents of most analyzed elements, excluding K and Ba, were generally low compared to those of average crust. Contents of most elements, except K and Ca, also correlated with sediment grain size, though the degree of relationship varied widely from one element to another. For fine-grained sediments, a distinction could be made between those in the central Yellow Sea and those in the Keum Estuary based on their characteristic elemental composition: the former were rich in Fe, Na, K, Mg, Ca and V, and the latter in Mn, Co and Ni. The element/aluminium ratios, on the other hand, showed that the central Yellow Sea muds were enriched in Fe, Mg, V, Ni, Cu and Zn and depleted in K, Mn, Ba and Sr relative to the mud located near the Korean Peninsula. Based on the analysis of these results, as well as of the influences of particular mineral phases or pollution effects, we could suggest geochemical criteria which can be used in distinguishing muds from the two different sources, the Keum River and the Yellow River: the former by the higher Mn content and the latter by the higher Mg and V contents, relative to each other.