• 한국해양공학회지
• /
• 제31권1호
• /
• pp.47-59
• /
• 2017

This study conducted numerical simulations using LES-WASS-3D ver. 2.0 to analyze the seawater intrusion characteristics of the incident waves in a coastal aquifer. LES-WASS-3D directly analyzed the nonlinear interaction between the seawater and freshwater in a coastal aquifer, as well as the wave-current interaction in the coastal area. First, the LES-WASS-3D results were compared with the existing experimental results for the mean water level under wave action in the coastal aquifer and seawater penetration into the coastal aquifer. The mean water level, shape and position of the seawater-freshwater interface, and intrusion distance were well implemented in the results. This confirmed the validity and effectiveness of LES-WASS-3D. The overall seawater penetration distance increases in the coastal aquifer as a result of wave set-up and run-up in the swash zone caused by continuous wave actions, and it increases with the wave height and period. Furthermore, a numerical verification was performed by comparing the suggested existing structure and newly suggested curtain wall as a measure against seawater penetration. An existing underground dam showed a better effect with increased height. Additionally, the suggested curtain wall had a better effect when the embedded depth was increased.

• 수산해양기술연구
• /
• 제58권1호
• /
• pp.59-67
• /
• 2022

This study assessed the levels of water qualities and microbials contamination of inland olive flounder farms in Jeju in the summers from 2015 to 2017. Three farms (A-C) located in a concentrated area using mixing coastal seawater and underground seawater and one farm (D) located in an independent area using only coastal seawater were selected. Total ammonia nitrogen (TAN) reached a maximum of 0.898 ± 1.024 mg/L as N in the coastal seawater of A-C, which was close to the limit of the water quality management goal of the fish farm. TAN in the influent from A-C was up to three times higher than that of D, so that the discharged water did not spread to a wide range area along the coast and continued to affect the influent. TAN of the effluent in A-C increased by 2.7-4.6 times compared to the influent, resulting in serious self-pollution in the flounder farm. Heterotrophic marine bacteria in the influent of A-C was about 600 times higher than D, and the discharge of A-C was increased by about 30 times compared to the influent.

• 한국수자원학회논문집
• /
• 제48권12호
• /
• pp.1023-1035
• /
• 2015

본 연구에서는 해수-담수-해안대수층의 비선형 상호작용을 직접 해석할 있는 PBM(Porous Body Model) 기반의 3차원 N-S Solver인 LES-WASS-3D ver 2.0을 적용하며, 해안대수층의 해수침투모의를 수행하였다. 이와 같은 N-S Solver를 적용한 해안대수층의 해수침투모의는 국내 최초 수행되는 것일 뿐만 아니라, 국외적으로도 찾아보기 어려운 새로운 수치해석방법이라고 할 수 있다. 먼저 적용하는 수치모델을 검증하기 위하여 해안대수층의 해수-담수 경계면에 관한 수리모형실험결과와 비교 검토하여 수치모델의 타당성 및 유효성을 확인하였다. 그리고 해수위 및 지하수위 변화를 고려한 해안대수층 내의 해수침투모의를 수행하여 해수위-지하수위 차와 해수위의 비(${\Delta}h/h$)의 증가에 따른 해안대수층 내의 유동장 그리고 해수-담수 경계면 분포 특성에 관하여 논의하였다. 또한 기존의 비확산 수치모델에서 도출할 수 없었던, ${\Delta}h/h$에 따른 해안대수층 내의 연직 염분농도로 부터 해수침투 특성을 파악하였으며, 최종적으로 지표화 할 수 있는 ${\Delta}h/h$가 해안대수층 내의 해수침투거리에 미치는 영향에 대하여 분석하였다. 이 결과로부터 ${\Delta}h/h$가 작을수록 해안대수층 내의 해수침투가 약해지는 메커니즘을 이해할 수 있었다.

• 터널과지하공간
• /
• 제14권3호
• /
• pp.229-240
• /
• 2004

연안대수층은 주요한 지하수 공급원으로서 이용될 수 있다. 그러나 연안대수층의 개발은 해수침투에 의한 대수층 오염을 야기할 수도 있다. 이에 따라 개발과정에서는 적절한 양수량과 양수정의 배치가 매우 중요하고, 이 들의 영향은 용질이동과 유동해석이 가능한 수치해석적 기법들을 적용하여 평가할 수 있다. 이 연구에서는 연안 자유면 대수층 모델에 대해 양수량 및 수리지질학적 변수들이 해수침투 특성에 미치는 영향을 SWICHA 코드를 이용하여 수치해석적으로 검토하였다. 수치해석과정에서는 유동 및 용질의 상호작용이 고려되었다. 경계 조건, 수리지질변수 등의 변화에 따른 해수담수 경계부에서의 염수 확산대 분포, 양수정 부근에서의 수두변화 등이 분석되었다.

• 한국습지학회지
• /
• 제3권2호
• /
• pp.107-118
• /
• 2001

The aim of this paper is to grasp eutrophication aspects in Namhae coastal seas, statistically analyzing existing data for their surface seawater and bottom mud. A pollution level(ignition loess) of bottom mud, on the whole, trended to increase as moving the coastal sea around Mokpo-Wando toward the east(Gyeongnam Namhae coastal seas). Especially, the pollution level(ignition loss=10.5%) of bottom mud for the coastal sea around Tongyeong-Keoje-Gosung was similar to that(10.3%) for the coastal sea around Masan-Jinhae, whose coastal marine pollution was the severest in Namhae coastal seas. It indicates that large amounts of pollutant from aqualculture facilities have been, thus far, accumulated on the coastal sea around Tongyeong-Keoje-Gosung, considering there was no significant inflow of sewage and industrial wastewater into this coastal sea. A COD, T-N, and T-P level of surface seawater, on the whole trended to increase as moving the coastal sea around Mokpo-Wando toward the east(Gyeongnam Namhae coastal seas). A COD level appeared to be the second grade of coastal water quality over the entire year throughout all Namhae coastal seas A T-N level exceeded the third grade of coastal water quality throughout all Namhae coastal seas except the coastal sea around Mokpo-Wando. Especially, a T-N level exceeded as many as three and six times over the third grade of coastal water quality in the coastal sea around Tongyeong-Keoje-Gosung and Masan-Jinhae, respectively. A T-P level appeared to be the second grade of coastal water quality in the coastal sea around Mokpo-Wando and the third grade of coastal water quality in the coastal sea around Yosu-Narnhae and Tongyeong-Keoje-Gosung, while it exceeded as many as two times over the third grade of coastal water quality. A degree of eutrophication of the surface seawater was 1.5 in the coastal sea around Mokpo-Wando and 11.9 In the coastal sea around Tongyeong-Keoje-Gosung, gradually increasing as moving toward the east(Gyeongnam Narnhae coastal seas). It sharply increased to 146.1 in the coastal sea around Masan-Jinhae. Because the degree of eutrophication throughout all Namhae coastal seas exceeded 1, a red tide organism could pose a possibility of proliferation at any place of Namhae coastal seas if other requirements were satisfied. It indicates that a red tide may move to another place once a red tide breaks out at a place of Namhae coastal seas.

• 대한토목학회논문집
• /
• 제44권4호
• /
• pp.465-482
• /
• 2024

The global use of groundwater in coastal areas has increased. Events such as seawater intrusion (SWI) are expected to increase along with the acceleration of natural disasters owing to environmental changes such as climate change, resulting in large-scale damage worldwide. Current trends in the research of coastal groundwater and related natural disasters include testing and verifying technologies using major case studies from individual countries. We identified global research trends in coastal groundwater, related these trends to changing environments and climate, and confirmed the qualitative and quantitative growth of these studies. This study describes the theoretical background and techniques for coastal groundwater analysis and details regional-scale SWI indicators based on analytical and numerical studies. This review highlights recent technologies that consider uncertainty and promotes discussions on field data obtained using new technologies. Finally, the research findings and trends for a regional coastal aquifer in Korea are discussed to describe recent SWI approaches for groundwater resources.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제7권1호
• /
• pp.63-77
• /
• 2002

Salinization is an important environmental problem encountered in coastal aquifers. In order to evaluate the salinization problem in the western coastal area of Korea, we have performed a regional hydrochemical study on shallow well groundwaters (N=229) collected within 10 km away from the coastline. The concentrations of analyzed solutes are very wide in range, suggesting that the hydrochemistry is controlled by several processes such as water-rock interaction, seawater mixing, and anthropogenic contamination. Based on the graphical interpretation of cumulative frequency curves for some hydrochemical parameters (esp., $Cl^{-}$ and ${NO_3}^-$), the collected water samples were grouped into two major populations (1) a background population whose chemistry is predominantly affected by water-rock interaction, and (2) an anomalous population which records the potential influences by either seawater mixing or anthropogenic pollution. The threshold values obtained are 34.7 mg/l for $Cl^{-}$ and 37.2 mg/l for ${NO_3}^-$, Using these two constituents, groundwaters were further grouped into four water types as follows (the numbers in parenthesis indicate the percentage of each type water) : (1) type 1 waters (38%) that are relatively poor in $Cl^{-}$ and ${NO_3}^-$, which may represent their relatively little contamination due to seawater mixing and anthropogenic pollution; (2) type 2 waters (21%) which are enriched in $Cl^{-}$, Indicating the considerable influence by seawater mixing; (3) ${NO_3}^-$-rich, type 3 waters (11%) which record significant anthropogenic pollution; and (4) type 4 waters (30%) enriched in both $Cl^{-}$ and ${NO_3}^-$, reflecting the effects of both seawater mixing and anthropogenic contamination. The results of the water type classification correspond well with the grouping on a Piper's diagram. On a Br x $10^4$versus Cl molar ratio diagram, most of type 2 waters are also plotted along or near the seawater mixing line. The discriminant analysis of hydrochemical data also shows that the classification of waters into four types are so realistic to adequately reflect the major process(es) proposed for the hydrochemical evolution of each water type. As a tool for evaluating the degree of seawater mixing, we propose a parameter called 'Seawater Mixing Index (S.M.I.)’ which is based on the concentrations of Na, Mg, Cl, and $SO_4$. All the type 1 and 3 waters have the S.M.I. values smaller than one, while type 2 and type 4 waters mostly have the values greater than 1. In the western coastal area of Korea, more than 21% of shallow groundwaters appear to be more or less affected by salinization process.

• 대한토목학회논문집
• /
• 제31권1B호
• /
• pp.71-85
• /
• 2011

한반도의 해안 지하수 및 해수면 수위, 수온, 그리고 전기전도도(Electrical Conductivity, EC) 관측 자료를 통해 경향성 분석을 실시하여, 한반도 대수층의 해수침투 영향을 연구하였다. 총 27개소의 지하수위 및 EC 자료를 분석한 결과 지하수위는 27개소 모두 안정된 경향을 보였으며, EC는 증가 9개소, 안정 10개소, 감소 8개소로서 안정 및 변동의 경향을 나타내고 있으며, 해수면 수온은 총 14개소의 관측소 중 증가 12개소, 안정 2개소로서 증가의 경향이 대부분인 것으로 나타났으며, 해수면 수위 또한 총 24개소의 관측소 중 증가 18개소, 안정 3개소, 감소 3개소로 대부분의 관측소가 증가의 경향을 보였다. 특히, 동해와 남해안보다 서해의 해수면수위, 수온 및 EC의 모든 연구 항목의 상승 경향성을 보이는 관측소 비율이 높은 것으로 분석되어, 서해안에서 해수침투 영향이 타 해안보다 심각한 것으로 판단되며, 이에 대한 연구 및 대책이 강구되어야 하겠다.

• 환경생물
• /
• 제26권4호
• /
• pp.303-310
• /
• 2008

Heavy metal concentration of Fe, Zn, Cu, Cd and Pb were analysed from seaweeds (Ulva pertusa, Sargassum thunbergii, Caulacanthus okamurae), sediments and seawater at the two experimental sites of Daebul and Sabjin industrial complex in Mokpo coastal area with a control site (Heugsando). Highest values of heavy metals were found at two experimental sites influencing by various pollution sources such as industrial drains, sewage and harbours. In contrast, the lowest concentrations was observed at the control site without any pollution source. The concentration levels of accumulated heavy metals were in the following order: seaweeds > sediments > seawater. Similar spatial distribution patterns were observed at the seaweeds, sediments and seawater for the highest mean values of the different heavy metals. This result show that seaweeds could be used as a biomonitors of heavy metals at coastal region.

• Environmental Engineering Research
• /
• 제15권1호
• /
• pp.15-21
• /
• 2010

This study was conducted to evaluated seawater bacteria and their seasonal characteristics in the arsenic contaminated coastal seawater of Yeosu Bay, the Republic of Korea. Arsenite-oxidizing bacteria play an important role in the seawater of the arsenic contaminated bay, with a variety of arsenic resistance system (ars) genotypes being present during summer. Specifically, Bacillus sp. strain SeaH-As22w (FJ607342), isolated from the bay, were found to contain the arsB, arrA and aoxR type operons, which are involved in arsenic resistance. The isolated bacteria showed relatively high tolerance to sodium arsenite (III; $NaAsO_2$) at concentrations as high as 50 mM. Additionally, batch seawater experiments showed that Bacillus sp. strain SeaH-As22w completely oxidized 1 mM of As (III) to As (V) within 10 days. Ecologically, the arsenic-oxidizing potential plays an important role in arsenic toxicity and mobility in As-contaminated coastal seawater of Yeosu Bay during all seasons because it facilitates the activity of Bacillus sp. groups.